Cardozo, J.

The defendant is a manufacturer of automobiles. It sold an automobile to a retail dealer. The retail dealer resold to the plaintiff. While the plaintiff was in the car, it suddenly collapsed. He was *385thrown out and injured. One of the wheels was made of defective wood, and its spokes crumbled into fragments. The wheel was not made by the defendant; it was bought from another manufacturer. There is evidence, however, that its defects could have been discovered by reasonable inspection, and that inspection was omitted. There is no claim that the defendant knew of the defect and willfully concealed it. The case, in other words, is not brought within the rule of Kuelling v. Lean Mfg. Co. (183 N. Y. 78). The charge is one, not of fraud, but of negligence. The question to be determined is whether the defendant owed a duty of care and vigilance to any one but the immediate purchaser.

The foundations of this branch of the law, at least in this state, were laid in Thomas v. Winchester (6 N. Y. 397). A poison was falsely labeled. The sale was made to a druggist, who in turn sold to a customer. The customer recovered damages from the seller who affixed the label. “The defendant’s negligence,” it was said, “put human life in imminent danger.” A poison falsely labeled is likely to injure any one who gets it. Because the danger is to be foreseen, there is a duty to avoid the injury. Cases were cited by way of illustration in which manufacturers were not subject to any duty irrespective of contract. The distinction was said to be that their conduct, though negligent, was not likely to result in injury to any one except the purchaser. We are not required to say whether the chance of injury was always as remote as the distinction assumes. Some of the illustrations might be rejected to-day. The principle of the distinction is for present purposes the important thing.

Thomas v. Winchester became quickly a landmark of the law. In the application of its principle there may at times have been uncertainty or even error. There has never in this state been doubt or disavowal of the principle itself. The chief cases are well known, yet to recall *386some of them will he helpful. Loop v. Litchfield (42 N. Y. 351) is the earliest. It was the case of a defect in a small balance wheel used on a circular saw. The manufacturer pointed out the defect to the buyer, who wished a cheap article and was ready to assume the risk. The risk can hardly have been an imminent one, for the wheel lasted five years before it broke. In the meanwhile the buyer had made a lease of the machinery. It was held that thti manufacturer was not answerable to the lessee. Loop v. Litchfield was followed in Losee v. Clute (51 N. Y. 494), the case of the explosion of a steam boiler. That decision has been criticised (Thompson on Negligence, 233; Shearman & Redfield on Negligence [6th ed.], § 117); but it must be confined to its special facts. It was put upon the ground that the risk of injury was too remote. The buyer in that case had not only accepted the boiler, hut had tested it. The manufacturer knew that his own test was not the final one. The finality of the test has a bearing on the measure of diligence owing to persons other than the purchaser (Beven, Negligence [3d ed.], pp. 50, 51, 54; Wharton, Negligence [2d ed.], § 134).

These early cases suggest a narrow construction of the rule. Later cases, however, evince a more liberal spirit. First in importance is Devlin v. Smith (89 N. Y. 470). The defendant, a contractor, built a scaffold for a painter. The painter’s servants were injured. The contractor was held liable: He knew that the scaffold, if improperly constructed, was a most dangerous trap. He knew that it was to he used by the workmen. He was building it for that very purpose. Building it for their use, he owed them a duty, irrespective of his contract with their master, to build it with care.

From Devlin v. Smith we pass over intermediate cases and turn to the latest case in this court in which Thomas v. Winchester was followed. That case is Statler v. Ray Mfg. Co. (195 N. Y. 478, 480). The defendant *387manufactured a large coffee urn. It was installed in a restaurant. When heated, the urn exploded and injured the plaintiff. W e held that the manufacturer was liable. We said that the urn “was of such a character inherently that, when applied to the purposes for which it was designed, it was liable to become a source of great danger to many people if not carefully and properly constructed.” It may be that Devlin v. Smith and Statler v. Ray Mfg. Co. have extended the rule of Thomas v. Winchester. If so, this court is committed to the extension. The defendant argues that things imminently dangerous to life are poisons, explosives, deadly weapons — things whose normal function it is to injure or destroy. But whatever the rule in Thomas v. Winchester may once have been, it has no longer that restricted meaning. A scaffold (Devlin v. Smith, supra) is not inherently a destructive instrument. It becomes destructive only if imperfectly constructed. A large coffee urn (Statler v. Ray Mfg. Co., supra) may have within itself, if negligently made, the potency of danger, yet no one thinks of it as an implement whose normal function is destruction. What is true of the coffee urn is equally true of bottles of aerated water (Torgeson v. Schultz, 192 N. Y. 156). We have mentioned only cases in this court. But the rule has received a like extension in our courts of intermediate appeal. In Burke v. Ireland (26 App. Div. 487), in an opinion by Cullen, J., it was applied to a builder who constructed a defective building; in Kahner v. Otis Elevator Co. (96 App. Div. 169) to the manufacturer of an elevator; in Davies v. Pelham Hod Elevating Co. (65 Hun, 573; affirmed in this court without opinion, 146 N. Y. 363) to a contractor who furnished a defective rope with knowledge of the purpose for which the rope was to be used. We are not required at this time either to approve or to disapprove the application of the rule that was made in these cases. It is enough that they help to characterize the trend of judicial thought.

*388 Devlin v. Smith was decided in 1882. A year later a very similar case came before the Court of Appeal in England (Heaven v. Pender, L. B. [11 Q. B. D.] 503). We find in the opinion of Brett, M. B., afterwards Lord Esher (p. 510), the same conception of a duty, irrespective of contract, imposed upon the manufacturer by the law itself: “Whenever one person supplies goods, or machinery, or the like, for the purpose of their being used by another person under such circumstances that every one of ordinary sense would, if he thought, recognize at once that unless he used ordinary care and skill with regard to the condition of the thing supplied or the mode of supplying it, there will be danger of injury to the person or property of him for whose use the thing is supplied, and who is to use it, a duty arises to use ordinary care and skill as to the condition or manner of supplying such thing.” He then points out that for a neglect of such ordinary care or skill whereby injury happens, the appropriate remedy is an action for negligence. The right to enforce this liability is not to be confined to the immediate buyer. The right, he says, extends to the persons or class of persons for whose use the thing is supplied. It is enough that the goods “would in all probability be used at once * * * before a reasonable opportunity for discovering any defect which might exist,” and that the thing supplied is of such a nature “that a neglect of ordinary care or skill as to its condition or the manner of supplying it would probably cause danger to the person or property of the person for whose use it was supplied, and who was about to use it.” On the other hand, he would exclude a case “in which the goods are supplied under circumstances in which it would be a chance by whom they would be used or whether they would be used or not; or whether they would be used before there would probably be means of observing any defect,” or where the goods are of such a nature that “a want of care or skill as to their condition or the manner 'of supplying them would not probably *389produce danger of injury to person or property.” What was said by Lord Esher in that case did not command the full assent of his associates. His opinion has been criticised “as requiring every man to take affirmative precautions to protect his neighbors as well as to refrain from injuring them” (Bohlen, Affirmative Obligations in the Law of Torts, 44 Am. Law Reg. [N. S.] 341). It may not be an accurate exposition of the law of England. Perhaps it may need some qualification even in our own state. Like most attempts at comprehensive definition, it may involve errors of inclusion and of exclusion. But its tests and standards, at least in their underlying principles, with whatever qualification may be called for as they are applied to varying conditions, are the tests and standards of our law.

We hold, then, that the principle of Thomas v. Winchester is not limited to poisons, explosives, and things of like nature, to things which in their normal operation are implements of destruction. If the nature of a thing is such that it is reasonably certain to place life and limb in peril when negligently made, it is then a thing of danger. Its nature gives warning of the consequences to be expected. If to the element of danger there is added knowledge that the thing will housed by persons other than the purchaser, and used without new tests, then, irrespective of contract, the manufacturer of this thing of danger is under a duty to make it carefully. That is as far as we are required to go for the decision of this case. There must be knowledge of a danger, not merely possible, but probable. It is possible to use almost anything in a way that will make it dangerous if defective. That is not enough to charge the manufacturer with a duty independent of his contract. Whether a given thing is dangerous may be sometimes a question for the court and sometimes a question for the jury. There must also be knowledge that in the usual course of events the danger will he shared by others than the buyer. Such knowledge may often be *390inferred from the nature of the transaction. But it is possible that even knowledge of the danger and of the use will not always be enough. The proximity or remoteness of the relation is a factor to be considered. We are dealing now with the liability of the manufacturer of the finished product, who puts it on the market to be used without inspection by his customers. If he is negligent, where danger is to be foreseen, a liability will follow. We are not required at this time to say that it is legitimate to go back of the manufacturer of the finished product and hold the manufacturers of the component parts. To make their negligence a cause of imminent danger, an independent cause must often intervene; the manufacturer of the finished product must also fail in his duty of inspection. It may be that in those circumstances the negligence of the earlier members of the series is too remote to constitute, as to the ultimate user, an actionable wrong (Beven on Negligence [3d ed.], 50, 51, 51; Wharton on Negligence [2d ed.], § 134; Leeds v. N. Y. Tel. Co., 178 N. Y. 118; Sweet v. Perkins, 196 N. Y. 482; Hayes v. Hyde Park, 153 Mass. 511, 516). We leave that question open. We shall have to deal with it when it arises. The difficulty which it suggests is not present in this case. There is here no break in the chain of cause and effect. In such circumstances, the presence of a known danger, attendant upon a known use, makes vigilance a duty. We have put aside the notion that the duty to safeguard life and limb, when the consequences of negligence may be foreseen, grows out of contract and nothing else. We have put the source of the obligation where it ought to be. We have put its source in the law.

From this survey of the decisions, there thus emerges a definition of the duty of a manufacturer which enables us to measure this defendant’s liability. Beyond all question, the nature of an automobile gives warning of probable danger if its construction is defective. This *391automobile was designed to go fifty miles an hour. Unless its wheels were sound and strong, injury was almost certain. It was as much a thing of danger as a defective engine for a railroad. The defendant knew the danger. It knew also that the car would be used by persons other than the buyer. This was apparent from its size; there were seats for three persons. It was apparent also from the fact that the buyer was a dealer in cars, who bought to resell. The maker of this car supplied it for the use of purchasers from the dealer just as plainly as the contractor in Devlin v. Smith supplied the scaffold for use by the servants of the owner. The dealer was indeed the one person of whom it might be said with some approach to certainty that by him the car would not be used. Yet the defendant would have us say that he was the one person whom it was under a legal duty to protect. The law does not lead us to so inconsequent a conclusion. Precedents drawn from the days of travel by stage coach do not fit the conditions of travel to-day. The principle that the danger must be imminent does not change, but the things subject to the principle do change. They are whatever the needs of life in a developing civilization require them to be.

In reaching this conclusion, we do not ignore the decisions to the contrary in other jurisdictions. It was held in Cadillac M. C. Co. v. Johnson (221 Fed. Rep. 801) that an automobile is not within the rule of Thomas v. Winchester. There was, however, a vigorous dissent. Opposed to that decision is one of the Court of Appeals of Kentucky (Olds Motor Works v. Shaffer, 145 Ky. 616). The earlier cases are summarized by Judge Sanborn in Huset v. J. I. Case Threshing Machine Co. (120 Fed. Rep. 865). Some of them, at first sight inconsistent with our conclusion, may be reconciled upon the ground that the negligence was too remote, and that another cause had intervened. But even when they cannot be reconciled, the difference is rather in the applica*392tion of the principle than in the principle itself. Judge Sanborn says, for example, that the contractor who builds a bridge, or the manufacturer who builds a car, cannot ordinarily foresee injury to other persons than the owner as the probable result (120 Fed. Rep. 865, at p. 867). We take a different view. We think that injury to others is to be foreseen not merely as a possible, but as an almost inevitable result. (See the trenchant criticism in Bohlen, supra, at p. 351). Indeed, Judge Sanborn concedes that his view is not to be reconciled with our decision in Devlin v. Smith (supra). The doctrine of that decision has now become the settled law of this state, and we have no desire to depart from it.

In England the limits of the rule are still unsettled. Winterbottom v. Wright (10 M. & W. 109) is often cited. The defendant undertook to provide a mail coach to carry the mail bags. The coach broke down from latent defects in its construction. The defendant, however, was not the manufacturer. The court held that he was not liable for injuries to a passenger. The case was decided on a demurrer to the declaration. Lord Esher points out in Heaven v. Pender (supra, at p. 513) that the form of the declaration was subject to criticism. It did not fairly suggest the existence of a duty aside from the special contract which was the plaintiff’s main reliance. (See the criticism of Winterbottom v. Wright, in Bohlen, supra, at pp. 281, 283). At all events, in Heaven v. Pender (supra) the defendant, a dock owner, who put up a staging outside a ship, was held liable to the servants of the shipowner. In Elliott v. Hall (15 Q. B. D. 315) the defendant sent out a defective truck laden with goods which he had sold. The buyer’s servants unloaded it, and were injured because of the defects. It was held that the defendant was under a duty “not to he guilty of negligence with regard to the state and condition of the truck.” There seems to have been a *393return to the doctrine of Winterbottom v. Wright in Earl v. Lubbock (L. B. [1905] 1 K. B. 253). In that case, however, as in the earlier one, the defendant was not the manufacturer. He had merely made a contract to keep the van in repair. A later case (White v. Steadman, L. R. [1913], 3 K. B. 340, 348) emphasizes that element. A livery stable keeper who sent out a vicious horse was held liable not merely to his customer but also to another occupant of the carriage, and Thomas v. Winchester was cited and followed (White v. Steadman, supra, at pp. 348, 349). It was again cited and followed in Dominion Natural Gas Co. v. Collins (L. R. [1909] A. C. 640, 646). From these cases a consistent principle is with difficulty extracted. The English courts, however, agree with ours in holding that one who invites another to make use of an appliance is bound to the exercise of reasonable care (Caledonian Ry. Co. v. Mulholland, L. R. [1898] A. C. 216, 227; Indermaurv. Dames, L. R. [1 C. P.] 274). That at bottom is the underlying principle of Devlin v. Smith. The contractor who builds the scaffold invites the owner’s workmen to use it. The manufacturer who sells the automobile to the retail dealer invites the dealer’s customers to use it. The invitation is addressed in the one case to determinate persons and in the other to an indeterminate class, but in each case it is equally plain, and in each its consequences must be the same.

There is nothing anomalous in a rule which imposes upon A, who has contracted with B, a duty to C and D and others according as he knows or does not know that the subject-matter of the contract is intended for their use. We may find an analogy in the law which measures the liability of landlords. If A leases to B a tumbledown house he is not liable, in the absence of fraud, to B’s guests who enter it and are injured. This is because B is then under the duty to repair it, the lessor has the right to suppose that he will fulfill that duty, and, if he *394omits to do so, his guests must look to him (Bohlen, supra, at p. 276). But if A leases a building to be used by the lessee at once as a place of public entertainment, the rule is different. There injury to persons other than the lessee is to be foreseen, and foresight of the consequences involves the creation of a duty (Junhermann v. Tilyou R. Co., 213 N. Y. 404, and cases there cited).

In this view of the defendant’s liability there is nothing inconsistent with the theory of liability on which the case was tried. It is true that the court told the jury that “an automobile is not an inherently dangerous vehicle.” The meaning, however, is made plain by the context. The meaning is that danger is not to be expected when the vehicle is well constructed. The court left it to the jury to say whether the defendant ought to have foreseen that the car, if negligently constructed, would become “imminently dangerous.” Subtle distinctions are drawn by the defendant between things inherently dangerous and things imminently dangerous, but the case does not turn upon these verbal niceties. If danger was to be expected as reasonably certain, there was a duty of vigilance, and this whether you call the danger inherent or imminent. In varying forms that thought was put before the jury. We do not say that “the court would not have been justified in ruling as a matter of law that the car was a dangerous thing. If there was any error, it was none of which the defendant can complain.

We think the defendant was not absolved from a duty of inspection because it bought the wheels from a reputable manufacturer. It was not merely a dealer in automobiles. It was a manufacturer of automobiles. It was responsible for the finished product. It was not at liberty to put the finished product on the market without subjecting the component parts to ordinary and simple tests (Richmond & Danville R. R. Co. v. Elliott, 149 U. S. 266, 272). Under the charge of the trial judge nothing more was *395required of it. The obligation to inspect must vary with the nature of the thing to be inspected. The more probable the danger, the greater the need of caution. There is little analogy between this case and Carlson v. Phoenix Bridge Co. (132 N. Y. 273), where the defendant bought a tool for a servant’s use. The making of tools was not the business in which the master was engaged. Reliance on the skill of the manufacturer was proper and almost inevitable. But that is not the defendant’s situation. Both by its relation to the work and by the nature of its business, it is charged with a stricter duty.

Other rulings complained of have been considered, but no error has been found in them.

The judgment should be affirmed with costs.

Willard Bartlett, Ch. J. (dissenting).

The plaintiff was injured in consequence of the collapse of a wheel of an automobile manufactured by the defendant corporation which sold it to a firm of automobile dealers in Schenectady, who in turn sold the car to the plaintiff. The wheel was purchased by the Buick Motor Company, ready made, from the Imperial Wheel Company of Flint, Michigan, a reputable manufacturer of automobile wheels which had furnished the defendant with eighty thousand wheels, none of which had proved to be made of defective wood prior to the accident in the present case. The defendant relied upon the wheel manufacturer to make all necessary tests as to the strength of the material therein and made no such tests itself. The present suit is an action for negligence brought by the subvendee of the motor car against the manufacturer as the original vendor. The evidence warranted a finding by the jury that the wheel which collapsed was defective when it left the hands of the defendant. The automobile was being prudently operated at the time of the accident and was moving at a speed of only eight miles an hour. There was *396no allegation or proof of any actual knowledge of the defect on the part of the defendant or any suggestion that any element of fraud or deceit or misrepresentation entered into the sale.

The theory upon which the case was submitted to the jury by the learned judge who presided at the trial was that, although an automobile is not an inherently dangerous vehicle, it may become such if equipped with a weak wheel; and "that if the motor car in question, when it was put upon the market was in itself inherently dangerous by reason of its being equipped with a weak wheel, the 'defendant was chargeable with a knowledge of the defect so far as it might be discovered by a reasom able inspection and the application of reasonable tests. This liability, it was further held, was not limited to the original vendee, but extended to a subvendee like the plaintiff, who was not a party to the original contract of sale.

I think that these rulings, which have been approved by the Appellate Division, extend the liability of the vendor of a manufactured article further than any case which has yet received the sanction of this court. It has heretofore been held in this state that the liability of the vendor of a manufactured article for negligence arising out of the existence of defects therein does not extend to strangers injured in consequence of such defects but is confined to the immediate vendee. The exceptions to this general rule which have thus far been recognized in New York are cases in which the article sold was of such a character that danger to life or limb was involved in the ordinary use thereof; in other words, where the article sold was inherently dangerous. As has already been pointed out, the learned trial judge instructed the jury that an automobile is not an inherently dangerous vehicle.

The late Chief Justice Cooley of Michigan, one of the most learned and accurate of American law writers, *397states the general rule thus: “The general rule is that a contractor, manufacturer, vendor or furnisher of an article is not liable to third parties who have no contractual relations with him for negligence in the construction, manufacture or sale of such article.” (2 Cooley on Torts [3d ed.], I486.)

The leading English authority in support of this rule, to which all the later cases on the same subject refer, is Winterbottom v. Wright (10 Meeson & Welsby, 109), which was an action by the driver of a stage coach against a contractor who had agreed with the postmaster-general to provide and keep the vehicle in repair for the purpose of conveying the royal mail over a prescribed route. The coach broke down and upset, injuring the driver, who sought to recover against the contractor on account of its defective construction. The Court of Exchequer denied him any right of recovery on the ground that there was no privity of contract between the parties, the agreement having been made with the postmaster-general alone. i£If the plaintiff can sue,” said Lord Abinger, the Chief Baron, “every passenger or even any person passing along the road, who was injured by the upsetting of the coach, might bring a similar action. Unless we confine the operation of such contracts as this to the parties who enter into them, the most absurd and outrageous consequences, to which I can see no limit, would ensue.”

The doctrine of that decision was recognized as the law of this state by the leading New York case of Thomas v. Winchester (6 N. Y. 397, 408), which, however, involved an exception to the general rule. There the defendant, who was a dealer in medicines, sold to a druggist a quantity of belladonna, which is a deadly poison, negligently labeled as extract of dandelion. The druggist in good faith used the poison in filling a prescription calling for the harmless dandelion extract and the plaintiff for whom the prescription was put up was poisoned by the *398belladonna. This court held that the original vendor was liable for the injuries suffered by the patient. Chief Judge Ruggles, who delivered the opinion of the court, distinguished between an act of negligence imminently dangerous to the lives of others and one that is not so, saying: “If A. build a wagon and sell it to B., who sells it to C. and C. hires it to D., who in consequence of the gross negligence of A. in building the wagon is overturned and injured, D. cannot recover damages against A., the builder. A.’s obligation to build the wagon faithfully, arises solely out of his contract with B. The public have nothing to do with it. * * * So, for the same reason, if a horse be defectively shod by a smith, and a person hiring the horse from the owner is thrown and injured in consequence of the smith’s negligence in shoeing; the smith is not liable for the injury. ”

In Torgeson v. Schultz (192 N. Y. 156, 159) the defendant was the vendor of bottles of aerated water which were charged under high pressure and likely to explode unless used with precaution when exposed to sudden changes of temperature. The plaintiff, who was a servant of the purchaser, was injured by the explosion of one of these bottles. There was evidence tending to show that it had not been properly tested in order to insure users against such accidents. We held that the defendant corporation was liable notwithstanding the absence of any contract relation between it and the plaintiff “under the doctrine of Thomas v. Winchester (supra), and similar cases based upon the duty of the vendor of an article dangerous in its nature, or likely to become so in the course of the ordinary usage to be contemplated by the vendor, either to exercise due care to warn users of the danger or to take reasonable care to present the article sold from proving dangerous when subjected only to customary usage.” The character of the exception to the general rule limiting liability for negligence to the original parties to the contract of sale, was still more clearly stated by Judge *399Hiscock, writing for the court in Statler v. Ray Manufacturing Co. (195 N. Y. 478, 482), where he said that “in the case of an article of an inherently dangerous nature, a manufacturer may become liable for a negligent construction which, when added to the inherent character of the appliance, makes it imminently dangerous, and causes or contributes to a resulting injury not necessarily incident to the use of such an article if properly constructed, but naturally following from a defective construction.” In that case the injuries were inflicted by the explosion of a battery of steam-driven coffee urns, constituting an appliance liable to become dangerous in the course of ordinary usage.

The case of Devlin v. Smith (89 N. Y. 470) is cited as an authority in conflict with the view that the liability of the manufacturer and vendor extends to third parties only when the article manufactured and sold is inherently dangerous. In that case the builder of a scaffold ninety feet high which was erected for the purpose of enabling painters to stand upon it, was held to be liable to the administratrix of a painter who fell therefrom and was killed, being at the time in the employ of the person for whom the scaffold was built. It is said that the scaffold if properly constructed was not inherently dangerous; and hence that this decision affirms the existence of liability in the case of an article not dangerous in itself but made so only in consequence of negligent construction. Whatever logical force there may be in this view it seems to me clear from the language of Judge Rapallo, who wrote the opinion of the court, that the scaffold was deemed to be an inherently dangerous structure; and that the case was decided as it was because the court entertained that view. Otherwise he would hardly have said, as he did, that the circumstances seemed to bring the case fairly within the principle of Thomas v. Winchester.

I do not see how we can uphold the judgment in the *400present case without overruling what has been so often said by this court and other courts of like authority in reference to the absence of any liability for negligence on the part of the original vendor of an ordinary carriage to any one except his immediate vendee. The absence of such liability was the very point actually decided in the English case of Winterbottom v. Wright (supra), and the illustration quoted from the opinion of Chief Judge Ruggles in Thomas v. Winchester (supra) assumes that the law on the subject was so plain that the statement would be accepted almost as a matter of course. In the case at bar the defective wheel on an automobile moving only eight iniles an hour was not any more dangerous to the occupants of the car than a similarly defective wheel would be to the occupants of a carriage drawn by a horse at the same speed; and yet unless the courts have been all wrong on this question up to the present time there would be no liability to strangers to the original sale in the case of the horse-drawn carriage.

The rule upon which, in my judgment, the determination of this case depends, and the recognized exceptions thereto, were discussed by Circuit Judge Sanborn of the United States Circuit Court of Appeals in the Eighth Circuit, in Huset v. J. I. Case Threshing Machine Co. (120 Fed. Rep. 865) in an opinion which reviews all the leading American and English decisions on the subject up to the time when it was rendered (1903). I have already discussed the leading New York cases, but as to the rest I feel that I can add nothing to the learning of that opinion or the cogency of its reasoning. I have examined the cases to which Judge Sanborn refers, but if I were to discuss them at length I should be forced merely to paraphrase his language, as a study of the authorities he cites has led me to the same conclusion; and the repetition of what has already been so well said would contribute nothing to the advantage of the bench, the bar or the individual litigants whose case is before us.

*401A few cases decided since his opinion was written, however, may he noticed. In Earl v. Lubbock (L. R. 1905 [1 K. B. Div.] 253) the Court of Appeal in 1904 considered and approved the propositions of law laid down by the Court of Exchequer in Winterbottom v. Wright (supra), declaring that the decision in that case, since the year 1842, had stood the test of repeated discussion. The master of the rolls approved the principles laid down by Lord Abinger as based upon sound reasoning; and all the members of the court agreed that his decision was a controlling authority which must he followed. That the Federal courts still adhere to the general rule, as I have stated it, appears by the decision of the Circuit Court of Appeals in the Second Circuit, in March, 1915, in the case of Cadillac Motor Car Co. v. Johnson (221 Fed. Rep. 801). That case, like this, was an action by a subvendee against a manufacturer of automobiles for negligence in failing to discover that one of its wheels was defective, the court holding that such an action could not be maintained. It is true there was a dissenting opinion in that case, but it was based chiefly upon the proposition that rules applicable to stage coaches are archaic when applied to automobiles and that if the law did not afford a remedy to strangers to the contract the law should he changed. It this be true, the change should he effected by the legislature and not by the courts. A perusal of the opinion in that case and in the Huset case will disclose how uniformly the courts throughout this country have adhered to the rule and how consistently they have refused to broaden the scope of the exceptions. I think we should adhere to it in the case at bar and, therefore, I vote for a reversal of this judgment.

Hiscock, Chase and Cuddeback, JJ., concur with Cardozo, J., and Hogan, J., concurs in result; Willard Bartlett, Ch. J., reads dissenting opinion; Pound, J., not voting.

Judgment affirmed.

*456GIBSON, C. J.

Plaintiff, a waitress in a restaurant, was injured when a bottle of Coca Cola broke in her hand. She alleged that defendant company, which had bottled and delivered the alleged defective bottle to her employer, was negligent in selling “bottles containing said beverage which on account of excessive pressure of gas or by reason of some defect in the bottle was dangerous . . . and likely to explode.” This appeal is from a judgment upon a jury verdict in favor of plaintiff.

Defendant’s driver delivered several cases of Coca Cola to the restaurant, placing them on the floor, one on top of the other, under and behind the counter, where they remained at least thirty-six hours. Immediately before the accident, plaintiff picked up the top case and set it upon a near-by ice cream cabinet in front of and about three feet from the refrigerator. She then proceeded to take the bottles from the case with her right hand, one at a time, and put them into the refrigerator. Plaintiff testified that after she had placed three bottles in the refrigerator and had moved the fourth bottle about eighteen inches from the ease “it exploded in my hand.” The bottle broke into two jagged pieces and inflicted a deep five-inch cut, severing blood vessels, nerves and muscles of the thumb and palm of the hand. Plaintiff further testified that when the bottle exploded, “It made a sound similar to an electric light bulb that would have dropped. It made a loud pop.” Plaintiff’s employer testified, “I was about twenty feet from where it actually happened and I heard the explosion.” A fellow employee, on the opposite side of the counter, testified that plaintiff “had the bottle, I should judge, waist high, and I know that it didn’t bang either the case or the door or another bottle . . . when it popped. It sounded just like a fruit jar would blow up. . . .” The witness further testified that the contents of the bottle “flew all over herself and myself and the walls and one thing and another.”

The top portion of the bottle, with the cap, remained in plaintiff’s hand, and the lower portion fell to the floor but did not break. The broken bottle was not produced at the trial, the pieces having been thrown away by an employee of the restaurant shortly after the accident. Plaintiff, however, described the broken pieces, and a diagram of the bottle was made showing the location of the “fracture line” where the bottle broke in two.

*457One of defendant’s drivers, called as a witness by plaintiff, testified that he had seen other bottles of Coca Cola in the past explode and had found broken bottles in the warehouse when he took the cases out, but that he did not know what made them blow up.

Plaintiff then rested her case, having announced to the court that being unable to show any specific acts of negligence she relied completely on the doctrine of res ipsa loquitur.

Defendant contends that the doctrine of res ipsa loquitur does not apply in this case, and that the evidence is insufficient to support the judgment.

Many jurisdictions have applied the doctrine in cases involving exploding bottles of carbonated beverages. (See Payne v. Rome Coca-Cola Bottling Co., 10 Ga.App. 762 [73 S.E. 1087] ; Stolle v. Anheuser-Busch, 307 Mo. 520 [271 S.W. 497, 39 A.L.R. 1001] ; Bradley v. Conway Springs Bottling Co., 154 Kan. 282 [118 P.2d 601] ; Ortego v. Nehi Bottling Works, 199 La. 599 [6 So.2d 677] ; MacPherson v. Canada Dry Ginger Ale, Inc., 129 N.J.L. 365 [29 A.2d 868]; Moeres v. Coca-Cola Bottling Co., 290 Mich. 567 [287 N.W. 922] ; Benkendorfer v. Garrett (Tex. Civ. App.), 143 S.W.2d 1020.) Other courts for varying reasons have refused to apply the doctrine in such cases. (See Gerber v. Faber, 54 Cal.App.2d 674 [129 P.2d 485] ; Loebig’s Guardian v. Coca-Cola Bottling Co., 259 Ky. 124 [81 S.W.2d 910]; Stewart v. Crystal Coca-Cola Bottling Co., 50 Ariz. 60 [68 P.2d 952]; Glaser v. Seitz, 35 Misc. 341 [71 N.Y.S. 942]; Luciano v. Morgan, 267 App. Div. 785 [45 N.Y.S.2d 502]; cf. Berkens v. Denver Coca-Cola Bottling Co., 109 Colo. 140 [122 P.2d 884]; Ruffin v. Coca Cola Bottling Co., 311 Mass. 514 [42 N.E.2d 259]; Slack v. Premier-Pabst Corporation, 40 Del. 97 [5 A.2d 516] ; Wheeler v. Laurel Bottling Works, 111 Miss. 442 [71 So. 743, L.R.A. 1916E 1074] ; Seven-Up Bottling Co. v. Gretes, _Va._[27 S.E.2d 925]; Dail v. Taylor, 151 N.C. 284 [66 S.E. 135, 28 L.R.A.N.S. 949].) It would serve no useful purpose to discuss the reasoning of the foregoing cases in detail, since the problem is whether under the facts shown in the instant case the conditions warranting application of the doctrine have been satisfied.

Res ipsa loquitur does not apply unless (1) defendant had exclusive control of the thing causing the injury and (2) the accident is of such a nature that it ordinarily *458would not occur in the absence of negligence by the defendant. (Honea v. City Dairy, Inc., 22 Cal.2d 614, 616-617 [140 P.2d 369], and authorities there cited; cf. Hinds v. Wheadon, 19 Cal.2d 458, 461 [121 P.2d 724]; Prosser on Torts [1941], 293-301.)

Many authorities state that the happening of the accident does not speak for itself where it took place some time after defendant had relinquished control of the instrumentality causing the injury. Under the more logical view, however, the doctrine may be applied upon the theory that defendant had control at the time of the alleged negligent act, although not at the time of the accident, provided plaintiff first proves that the condition of the instrumentality had not been changed after it left the defendant’s possession. (See cases collected in Honea v. City Dairy, Inc., 22 Cal.2d 614, 617-618 [140 P.2d 369].) As said in Dunn v. Hoffman Beverage Co., 126 N.J.L. 556 [20 A.2d 352, 354], “defendant is not charged with the duty of showing affirmatively that something happened to the bottle after it left its control or management; ... to get to the jury the plaintiff must show that there was due care during that period.” Plaintiff must also prove that she handled the bottle carefully. The reason for this prerequisite is set forth in Prosser on Torts, supra, at page 300, where the author states: “Allied to the condition of exclusive control in the defendant is that of absence of any action on the part of the plaintiff contributing to the accident. Its purpose, of course, is to eliminate the possibility that it was the plaintiff who was responsible. If the boiler of a locomotive explodes while the plaintiff engineer is operating it, the inference of his own negligence is at least as great as that of the defendant, and res ipsa loquitur will not apply until he has accounted for his own conduct.” (See, also, Olson v. Whitthorne (& Swan, 203 Cal. 206, 208-209 [263 P. 518, 58 A.L.R. 129].) It is not necessary, of course, that plaintiff eliminate every remote possibility of injury to the bottle after defendant lost control, and the requirement is satisfied if there is evidence permitting a reasonable inference that it was not accessible to extraneous harmful forces and that it was carefully handled by plaintiff or any third person who may have moved or touched it. (Cf. Prosser, supra, p. 300.) If such evidence is presented, the question becomes one for the trier of fact (see, e. g., *459 MacPherson v. Canada Dry Ginger Ale, Inc., 129 N.J.L. 365 [29 A.2d 868, 869]), and, accordingly, the issue should be submitted to the jury under proper instructions.

In the present case no instructions were requested or given on this phase of the case, although general instructions upon res ipsa loquitur were given. Defendant, however, has made no claim of error with reference thereto on this appeal. Upon an examination of the record, the evidence appears sufficient to support a reasonable inference that the bottle here involved was not damaged by any extraneous force after delivery to the restaurant by defendant. It follows, therefore, that the bottle was in some manner defective at the time defendant relinquished control, because sound and properly prepared bottles of carbonated liquids do not ordinarily explode when carefully handled.

The next question, then, is whether plaintiff may rely upon the doctrine of res ipsa loquitur to supply an inference that defendant’s negligence was responsible for the defective condition of the bottle at the time it was delivered to the restaurant. Under the general rules pertaining to the doctrine, as set forth above, it must appear that bottles of carbonated liquid are not ordinarily defective without negligence by the bottling company. In 1 Shearman and Redfield on Negligence (rev. ed. 1941), page 153, it is stated that: “The doctrine . . . requires evidence which shows at least the probability that a particular accident could not have occurred without legal wrong by the defendant.”

An explosion such as took place here might have been caused by an excessive internal pressure in a sound bottle, by a defect in the glass of a bottle containing a safe pressure, or by a combination of these two possible causes. The question is whether under the evidence there was a probability that defendant was negligent in any of these respects. If so, the doctrine of res ipsa loquitur applies.

The bottle was admittedly charged with gas under pressure, and the charging of the bottle was within the exclusive control of defendant. As it is a matter of common knowledge that an overcharge would not ordinarily result without negligence, it follows under the doctrine of res ipsa loquitur that if the bottle was in fact excessively charged an inference of defendant’s negligence would arise. If *460the explosion resulted from a defective bottle containing a safe pressure, the defendant would be liable if it negligently-failed to discover such flaw. If the defect were visible, an inference of negligence would arise from the failure of defendant to discover it. Where defects are discoverable, it may be assumed that they will not ordinarily escape detection if a reasonable inspection is made, and if such a defect is overlooked an inference arises that a proper inspection was not made. A difficult problem is presented where the defect is unknown and consequently might have been one not discoverable by a reasonable, practicable inspection. In the Honea case we refused to take judicial notice of the technical practices and information available to the bottling industry for finding defects which cannot be seen. In the present case, however, we are supplied with evidence of the standard methods used for testing bottles.

A chemical engineer for the Owens-Illinois Glass Company and its Pacific Coast subsidiary, maker of Coca Cola bottles, explained how glass is manufactured and the methods used in testing and inspecting bottles. He testified that his company is the largest manufacturer of glass containers in the United States, and that it uses the standard methods for testing bottles recommended by the glass containers association. A pressure test is made by taking a sample from each mold every three hours—approximately one out of every 600 bottles—and subjecting the sample to an internal pressure of 450 pounds per square inch, which is sustained for one minute. (The normal pressure in Coca Cola bottles is less than 50 pounds per square inch.) The sample bottles are also subjected to the standard thermal shock test. The witness stated that these tests are “pretty near” infallible.

It thus appears that there is available to the industry a commonly-used method of testing bottles for defects not apparent to the eye, which is almost infallible. Since Coca Cola bottles are subjected to these tests by the manufacturer, it is not likely that they contain defects when delivered to the bottler which are not discoverable by visual inspection. Both new and used bottles are filled and distributed by defendant. The used bottles are not again subjected to the tests referred to above, and it may be inferred that defects not discoverable by visual inspection do not develop in bottles after they are manufactured. Obviously, if such defects do *461occur in used bottles there is a duty upon the bottler to make appropriate tests before they are refilled, and if such tests are not commercially practicable the bottles should not be re-used. This would seem to be particularly true where a charged liquid is placed in the bottle. It follows that a defect which would make the bottle unsound could be discovered by reasonable and practicable tests.

Although it is not clear in this case whether the explosion was caused by an excessive charge or a defect in the glass, there is a sufficient showing that neither cause would ordinarily have been present if due care had been used. Further, defendant had exclusive control over both the charging and inspection of the bottles. Accordingly, all the requirements necessary to entitle plaintiff to rely on the doctrine of res ipsa loquitur to supply an inference of negligence are present.

It is true that defendant presented evidence tending to show that it exercised considerable precaution by carefully regulating and cheeking the pressure in the bottles and by making visual inspections for defects in the glass at several stages during the bottling process. It is well settled, however, that when a defendant produces evidence to rebut the inference of negligence which arises upon application of the doctrine of res ipsa loquitur, it is ordinarily a question of fact for the jury to determine whether the inference has been dispelled. (Druzanich v. Criley, 19 Cal.2d 439, 444 [122 P.2d 53]; Michener v. Hutton, 203 Cal. 604, 610 [265 P. 238, 59 A.L.R. 480].)

The judgment is affirmed.

Shenk, J., Curtis, J., Carter, J., and Sehauer, J., concurred.

TRAYNOR, J.

I concur in the judgment, but I believe the manufacturer’s negligence should no longer be singled out as the basis of a plaintiff’s right to recover in cases like the present one. In my opinion it should now be recognized that a manufacturer incurs an absolute liability when an article that he has placed on the market, knowing that it is to be used, without inspection, proves to have a defect that causes injury to human beings. McPherson v. Buick Motor Co., 217 382 [111 N.E. 1050], Ann.Cas. 1916C 440, L.R.A. 1916F, established the principle, recognized by this court, that irrespective of privity of contract, the manufacturer *462is responsible for an injury caused by such an article to any person who comes in lawful contact with it. (Sheward v. Virtue, 20 Cal.2d 410 [126 P.2d 345]; Kalash v. Los Angeles Ladder Co., 1 Cal.2d 229 [34 P.2d 481].) In these cases the source of the manufacturer’s liability was his negligence in the manufacturing process or in the inspection of component parts supplied by others. Even if there is no negligence, however, public policy demands that responsibility be fixed wherever it will most effectively reduce the hazards to life and health inherent in defective products that reach the market. It is evident that the manufacturer can anticipate some hazards not. Those who suffer injury from defective products are unprepared to meet its consequences. The cost of an injury and the loss of time or health may be an overwhelming misfortune to the person injured, and a needless one, for the risk of injury can be insured by the manufacturer and distributed among the public as a cost of doing business. It is to the public interest to discourage the marketing of products having defects that are a menace to the public. If such products nevertheless find their way into the market it is to the public interest to place the responsibility for whatever injury they may cause upon the manufacturer, who, even if he is not negligent in the manufacture of the product, is responsible for its reaching the market. However intermittently such injuries may occur and however haphazardly they may strike, the risk of their occurrence is a constant risk and a general one. Against such a risk there should be general and constant protection and the manufacturer is best situated to afford such protection.

The injury from a defective product does not become a matter of indifference because the defect arises from causes other than the negligence of the manufacturer, such as negligence of a submanufacturer of a component part whose defects could not be revealed by inspection (see Sheward v. Virtue, 20 Cal.2d 410 [126 P.2d 345]; O’Rourke v. Bay & Night Water Heater Co., Ltd., 31 Cal.App.2d 364 [88 P.2d 191]; Smith v. Peerless Glass Co., 259 N.Y. 292 [181 N.E. 576]), or unknown causes that even by the device of res ipsa loquitur cannot be classified as negligence of the manufacturer. The inference of negligence may be dispelled by an affirmative showing of proper care. If the evidence against the fact in*463ferred is “clear, positive, uncontradicted, and of such a nature that it cannot rationally be disbelieved, the court must instruct the jury that the nonexistence of the fact has bee established as a matter of law.” (Blank v. Coffin, 20 Cal.2 457, 461 [126 P.2d 868].) An injured person, however, is not ordinarily in a position to refute such evidence or identify the cause of the defect, for he can hardly be familiar with the manufacturing process as the manufacturer himself is. In leaving it to the jury to decide whether the inference has been dispelled, regardless of the evidence against it, the negligence rule approaches the rule of strict liability. It is needlessly circuitous to make negligence the basis of recovery and impose what is in reality liability without negligence. If public policy demands that a manufacturer of goods be responsible for their quality regardless of negligence there is no reason not to fix that responsibility openly.

In the case of foodstuffs, the public policy of the state is formulated in a criminal statute. Section 26510 of the Health and Safety Code prohibits the manufacturing, preparing, compounding, packing, selling, offering for sale, or keeping for sale, or advertising within the state, of any adulterated food. Section 26470 declares that food is adulterated when “it has been produced, prepared, packed, or held under insanitary conditions whereby it may have been rendered diseased, unwholesome or injurious to health.” The statute imposes criminal liability not only if the food is adulterated, but if its container, which may be a bottle (§ 26451), has any deleterious substance (§26470 (6)), or renders the product injurious to health. (§26470 (4)). The criminal liability under the statute attaches without proof of fault, so thaf the manufacturer is under the duty of ascertaining whether an article manufactured by him is safe. (People v. Schwartz, 28 Cal.App.2d Supp. 775 [70 P.2d 1017].) Statutes of this kind result in a strict liability of the manufacturer in tort to the member of the public injured. (See eases cited in Prosser, Torts, p. 693, note 69.)

The statute may well be applicable to a bottle whose defects cause it to explode. In any event it is significant that the statute imposes criminal liability without fault, reflecting the public policy of protecting the public from dangerous products placed on the market, irrespective of negligence in their manufacture. While the Legislature imposes criminal lia*464bility only with regard to food products and their containers, there are many other sources of danger. It is to the public interest to prevent injury to the public from any defective goods by the imposition of civil liability generally.

The retailer, even though not equipped to test a product, is under an absolute liability to his customer, for the implied warranties of fitness for proposed use and merchantable quality include a warranty of safety of the product. (Goetten Owl Drug Co., 6 Cal.2d 683 [59 P.2d 142] ; Mix v. Ingersoll Candy Co., 6 Cal.2d 674 [59 P.2d 144] ; Gindraux v. Maurice Mercantile Co., 4 Cal.2d 206 [47 P.2d 708]; Jensen v. Berris, Cal.App.2d 537 [88 P.2d 220]; Ryan v. Progressive Grocery Stores, 255 N.Y. 388 [175 N.E. 105; 74 A.L.R. 339] ; Race v. Krum, 222 N.Y. 410 [118 N.E. 853, L.R.A. 1918F 1172].) This warranty is not necessarily a contractual one (Chamberlain Co. v. Allis-Chalmers etc. Co., 51 Cal.App.2d 520, 524 [125 P.2d 113]; see 1 Williston on Sales, 2d ed., §§ 197-201), for public policy requires that the buyer be insured at the seller’s expense against injury. (Race v. Krum, supra; Ryan v. Progressive Grocery Stores, supra; Chapman v. Roggenkamp, 182 Ill.App. 117, 121; Ward v. Great Atlantic & Pacific Tea Co., 231 Mass. 90, 94 [120 N.E. 225, 5 A.L.R. 242]; see Prosser, The Implied Warranty of Merchantable Quality, 27 Minn.L.Rev. 117, 124; Brown, The Liability of Retail Dealers For Defective Food Products, 23 Minn.L.Rev. 585.) The courts recognize, however, that the retailer cannot bear the burden of this warranty, and allow him to recoup any losses by means of the warranty of safety attending the wholesaler’s or manufacturer’s sale to him. (Ward v. Great Atlantic & Pacific Tea Co., supra; see Waite, Retail Responsibility and Judicial Law Making, 34 Mich.L.Rev. 494, 509.) Such a procedure, however, is needlessly circuitous and engenders wasteful litigation. Much would be gained if the injured person could base his action directly on the manufacturer’s warranty.

The liability of the manufacturer to an immediate buyer injured by a defective product follows without proof of negligence from the implied warranty of safety attending the sale. Ordinarily, however, the immediate buyer is a dealer who does not intend to use the product himself, and if the warranty of safety is to serve the purpose of protecting health and safety it must give rights to others than the dealer. In the words *465of Judge Cardozo in the McPherson ease: “The dealer was indeed the one person of whom it might be said with some approach to certainty that by him the car would not be used.” Yet, the defendant would have us say that he was the one person whom it was under a legal duty to protect. The law does not lead us to so inconsequent a solution.” While the defendant’s negligence in the McPherson case made it unnecesssary for the court to base liability on warranty, Judge Cardozo’s reasoning recognized the injured person as the real party in interest and effectively disposed of the theory that the liability of the manufacturer incurred by his warranty should apply only to the immediate purchaser. It thus paves the way for a standard of liability that would make the manufacturer guarantee the safety of his product even when there is no negligence.

This court and many others have extended protection according to such a standard to consumers of food products, taking the view that the right of a consumer injured by unwholesome food does not depend “upon the intricacies law of sales” and that the warranty of the manufacturer to the consumer in absence of privity of contract rests on public policy. (Klein v. Duchess Sandwich Co., Ltd., 14 Cal.2d 282 [93 P.2d 799]; Ketterer v. Armour & Co., 200 F. 321, 322, 323 [160 C.C.A. 111, L.R.A. 1918D 798]; Decker & Sons v. Capps, 139 Tex. 609 [164 S.W.2d 828, 142 A.L.R. 1479]; see Perkins, Unwholesome Food As A Source of Liability, 5 Iowa L.Bull. 6, 86.) Dangers to life and health inhere in other consumers’ goods that are defective and there is no reason to differentiate them from the dangers of defective food products. (See Bohlen, Studies in Torts, Basis of Affirmative Obligations, American Cases Upon The Liability of Manufacturers and Vendors of Personal Property, 109, 135; Llewellyn, On Warranty of Quality and Society, 36 Col.L.Rev. 699, 704, note 14; Prosser, Torts, p. 692.)

In the food products cases the courts have resorted to various fictions to rationalize the extension of the manufacturer’s warranty to the consumer: that a warranty runs with the chattel; that the cause of action of the dealer is assigned to the consumer; that the consumer is a third party beneficiary of the manufacturer’s contract with the dealer. They have also held the manufacturer liable on a mere fiction of negli*466gence: “Practically he must know it [the product] is fit, or bear the consequences if it proves destructive.” (Parks v. C. C. Yost Pie Co., 93 Kan. 334 [144 P. 202, L.R.A. 1915C 179]; see Jeanblane, Manufacturer’s Liability to Persons Other Than Their Immediate Vendees, 24 Va.L.Rev. 134.) Such fictions are not necessary to fix the manufacturer’s liability under a warranty if the warranty is severed from the contract of sale between the dealer and the consumer and based on the law of torts (Decker & Sons v. Capps, supra; Prosser, Torts, p. 689) as a strict liability. (See Green v. General Petroleum Corp., 205 Cal. 328 [270 P. 952, 60 A.L.R. 475]; McGrath v. Basich Bros. Const. Co., 7 Cal.App.2d 573, 46 P.2d 981]; Prosser, Nuisance Without Fault, 20 Tex.L. Rev., 399, 403; Feezer, Capacity To Bear The Loss As A Factor In The Decision Of Certain Types of Tort Cases, 78 U. of Pa.L.Rev. 805, 79 U. of Pa.L.Rev. 742; Carpenter, The Doctrine of Green v. General Petroleum Corp., 5 So.Cal.L.Rev. 263, 271; Pound, The End of Law As Developed In Legal Rules And Doctrines, 27 Harv.L.Rev. 195, 233.) Warranties are not necessarily rights arising under a contract. An action on a warranty “was, in its origin, a pure action of tort,” and only late in the historical development of warranties was an action in assumpsit allowed. (Ames, The History of Assumpsit, 2 Harv.L.Rev. 1, 8; 4 Williston on Contracts (1936) § 970.) “And it is still generally possible where a distinction of procedure is observed between actions of tort and of contract to frame the declaration for breach of warranty in tort.” (Williston, loc. cit.; see Prosser, Warranty On Merchantable Quality, 27 Minn.L.Rev. 117, 118.) On the basis of the tort character of an action on a warranty, recovery has been allowed for wrongful death as it could not be in an action for breach of contract. (Greco v. S. S. Kresge Co., 277 N.Y. 26 [12 N.E.2d 577, 115 A.L.R. 1020]; see Schlick v. New York Dugan Bros., 175 Mise. 182 [22 N.Y.S.2d 238]; Prosser, op. cit., p. 119.) As the court said in Greco v. S. S. Kresge Co., supra, “Though the action may be brought solely for the breach of the implied warranty, the breach is a wrongful act, a default, and, in its essential nature, a tort.” Even a seller’s express warranty can arise from a noncontractual affirmation inducing a person to purchase the goods. (Chamberlain Co. v. Allis-Chalmers etc. Co., 51 Cal.App.2d 520 [125 P.2d 113].) “As an actual agreement to contract is not essential, the obli*467gation of a seller in such a case is one imposed by law as distinguished from one voluntarily assumed. It may be called an obligation either on a quasi-contract or quasi-tort, because remedies appropriate to contract and also to tort are applicable.” (1 Williston on Sales, 2d ed. §197; see Ballantine, Classification of Obligations, 15 Ill.L.Rev. 310, 325.)

As handicrafts have been replaced by mass production with its great markets and transportation facilities, the close relationship between the producer and consumer of a product has been altered. Manufacturing processes, frequently valuable secrets, are ordinarily either inaccessible to or beyond the ken of the general public. The consumer no longer has means or skill enough to investigate for himself the soundness of a product, even when it is not contained in a sealed package, and his erstwhile vigilance has been lulled by the steady efforts of manufacturers to build up confidence by advertising and marketing devices such as trade-marks. (See Thomas v. Winchester, 6 N.Y. 397 [57 Am.Dec. 455]; Baxter v. Ford Motor Co., 168 Wash; 456 [12 P.2d 409, 15 P.2d 1118, 88 A.L.R. 521]; Crist v. Art Metal Works, 230 App.Div. 114 [243 N.Y.S. 496], affirmed 255 N.Y. 624 [175 N.E. 341]; see also Handler, False and Misleading Advertising, 39 Yale L.J. 22; Rogers, Good Will, Trade-Marks and Unfair Trading (1914) ch. VI, A Study of The Consumer, p. 65 et seq.; Williston, Liability For Honest Misrepresentations As Deceit, Negligence Or Warranty, 42 Harv.L.Rev. 733; 18 Cornell L.Q. 445.) Consumers, no longer approach products warily but accept them on faith, relying on the reputation of the manufacturer or the trade mark. (See Max Factor & Co. v. Kunsman, 5 Cal.2d 446, 463 [55 P.2d 177]; Old Dearborn etc. Co. v. Seagram-Distillers Corp., 299 U.S, 183 [57 S.Ct. 139, 81 L.Ed. 109, 106 A.L.R. 1476]; Schechter, The Rational Basis of Trade Mark Protection, 40 Harv.L.Rev. 813, 818.) Manufacturers have sought to justify that faith by increasingly high standards of inspection and a readiness to make good on defective products by way of replacements and refunds. (See Bogert and Pink, Business Practices Regarding Warranties In The Sale Of Goods, 25 Ill.L.Rev. 400.) The manufacturer’s obligation to the consumer must keep pace with the changing relationship between them; it cannot be escaped because the marketing of a product has become so complicated as to require one or more *468intermediaries. Certainly there is greater reason to impose liability on the manufacturer than on the retailer who is but a conduit of a product that he is not himself able to test. (See Soule, Consumer Protection, 4 Encyclopedia of The Social Sciences, 282; Feezer, Manufacturer’s Liability For Injuries Caused By His Products: Defective Automobiles, 37 Mich.L. Rev. 1; Llewellyn, Cases And Materials on Sales, 340 et seq.)

The manufacturer’s liability should, of course, be defined in terms of the safety of the product in normal and proper use, and should not extend to injuries that cannot be traced to the product as it reached the market.

Appellant’s petition for a rehearing was denied August 3, 1944. Edmonds, J., voted for a rehearing.

*40OPINION OF THE COURT

Graffeo, J.

In this products liability case, defendants — a product manufacturer and retailer — were granted summary judgment dismissing plaintiffs’ complaint. Because we conclude that plaintiffs raised a triable issue of fact concerning whether a defective refrigerator caused the fire that resulted in plaintiffs’ injuries, we reverse and reinstate the complaint against these defendants.

Plaintiffs’ decedent Sandra Speller died in a house fire that also injured her seven-year-old son. It is undisputed that the fire originated in the kitchen. Plaintiffs commenced this action against Sears, Roebuck and Co., Whirlpool Corporation and the property owner alleging negligence, strict products liability and breach of warranty.* Relevant to this appeal, plaintiffs asserted that the fire was caused by defective wiring in the refrigerator, a product manufactured by Whirlpool and sold by Sears.

After discovery, defendants Sears and Whirlpool moved for summary judgment seeking dismissal of the complaint. Relying principally on a report issued by the New York City Fire Marshal, defendants rejected the refrigerator as the source of the fire, instead contending that a stovetop grease fire was the cause of the conflagration. Thus, they argued that their product was outside the chain of causation that resulted in plaintiffs’ damages.

In opposition to defendants’ motion for summary judgment, plaintiffs submitted excerpts from the depositions of two experts and an affidavit from a third, as well as other materials. Plaintiffs’ experts refuted the conclusions reached in the Fire Marshal’s report, opining that the fire started in the upper right quadrant of the refrigerator, an area with a concentration of electrical wiring. All three rejected the stove as the source of the fire. Plaintiffs also submitted portions of the deposition of a Whirlpool engineer retained as an expert by defendants. Although the engineer disputed that the fire originated in the refrigerator, he acknowledged that a fire would not occur in a refrigerator unless the product was defective.

*41Supreme Court denied defendants’ request for summary judgment, holding that plaintiffs’ submissions raised a triable issue of fact as to whether the fire was caused by a defect in the refrigerator. The Appellate Division reversed and granted the motion, dismissing the complaint as against Sears and Whirlpool. The Court reasoned that defendants’ evidence suggesting an alternative cause of the fire shifted the burden to plaintiffs to come forward with specific evidence of a defect. Characterizing the submissions of plaintiffs’ experts as “equivocal,” the Court concluded that plaintiffs failed to satisfy their burden of proof to withstand summary judgment. (294 AD2d 349, 350 [2002].) This Court granted plaintiffs leave to appeal.

A party injured as a result of a defective product may seek relief against the product manufacturer or others in the distribution chain if the defect was a substantial factor in causing the injury. “A product may be defective when it contains a manufacturing flaw, is defectively designed or is not accompanied by adequate warnings for the use of the product” (Liriano v Hobart Corp., 92 NY2d 232, 237 [1998]; Robinson v Reed-Prentice Div. of Package Mach. Co., 49 NY2d 471, 478 [1980]).

In this case, plaintiffs’ theory was that the wiring in the upper right quadrant of the refrigerator was faulty, causing an electrical fire which then spread to other areas of the kitchen and residence. Because that part of the refrigerator had been consumed in the fire, plaintiffs noted that it was impossible to examine or test the wiring to determine the precise nature of the defect. Thus, plaintiffs sought to prove their claim circumstantially by establishing that the refrigerator caused the house fire and therefore did not perform as intended.

New York has long recognized the viability of this circumstantial approach in products liability cases. Indeed its origins can be traced back to Codling v Paglia (32 NY2d 330, 337 [1973]), where this Court stated that a plaintiff “is not required to prove the specific defect” and that “[p]roof of necessary facts may be circumstantial.” In order to proceed in the absence of evidence identifying a specific flaw, a plaintiff must prove that the product did not perform as intended and exclude all other causes for the product’s failure that are not attributable to defendants (Halloran v Virginia Chems., 41 NY2d 386, 388 [1977]; see generally Kreindler, Rodriguez, Beekman and Cook, New York Law of Torts § 16.64, at 519-522 [15 West’s NY Prac Series 1997]). In this regard, New York law is consistent with the Restatement, which reads:

*42“It may be inferred that the harm sustained by the plaintiff was caused by a product defect existing at the time of sale or distribution, without proof of a specific defect, when the incident that harmed the plaintiff:

“(a) was of a kind that ordinarily occurs as a result of product defect; and

“(b) was not, in the particular case, solely the result of causes other than product defect existing at the time of sale or distribution” (Restatement [Third] of Torts: Products Liability § 3 [1998]).

Of course, if a plaintiffs proof is insufficient with respect to either prong of this circumstantial inquiry, a jury may not infer that the harm was caused by a defective product unless plaintiff offers competent evidence identifying a specific flaw (see Shelden v Hample Equip. Co., 59 NY2d 618 [1983], affg 89 AD2d 766 [3d Dept 1982]).

Here, in their motion for summary judgment, defendants focused on the second prong of the circumstantial inquiry, offering evidence that the injuries were not caused by their product but by an entirely different instrumentality — a grease fire that began on top of the stove. This was the conclusion of the Fire Marshal who stated during deposition testimony that his opinion was based on his interpretation of the burn patterns in the kitchen, his observation that one of the burner knobs on the stove was in the “on” position, and his conversation with a resident of the home who apparently advised him that the oven was on when the resident placed some food on the stovetop a few hours before the fire.

In order to withstand summary judgment, plaintiffs were required to come forward with competent evidence excluding the stove as the origin of the fire. To meet that burden, plaintiffs offered three expert opinions: the depositions of an electrical engineer and a fire investigator, and the affidavit of a former Deputy Chief of the New York City Fire Department. Each concluded that the fire originated in the refrigerator and not on the stove.

In his extensive deposition testimony, the electrical engineer opined that the fire started in the top-right-rear corner of the refrigerator, an area that housed the air balancing unit, thermostat, moisture control and light control. He stated that the wiring in this part of the appliance had been destroyed in the fire, making it impossible to identify the precise mechanical failure and, thus, he could only speculate as to the specific *43nature of the defect. He testified that the “most logical probability” was that a bad connection or bad splice to one of the components in that portion of the unit caused the wire to become “red hot” and to ignite the adjacent plastic. He tested the combustibility of the plastic and confirmed that the “plastic lights up very easily, with a single match” and continues to burn like candle wax. The engineer observed that the doors of the refrigerator were “slightly bellied out,” indicating they were blown out from the expanding hot gases inside the refrigerator. The wall behind the refrigerator was significantly damaged and the upper right quadrant was burned to such a degree that it was not likely to have been caused by an external fire. Interpreting the burn patterns differently from the Fire Marshal, the electrical engineer found that the cabinets above the stove, although damaged, were not destroyed to the extent he expected to find if there had been a stovetop grease fire.

Plaintiffs’ fire investigator similarly opined that the fire originated in the refrigerator’s upper right comer, in part basing his conclusion on his observations of the scene three days after the fire and his examination of the appliances. He also interviewed a witness to the fire. He testified that he eliminated the stove as the source of the fire after his examination of that appliance and the cabinets above it. Contrary to the testimony of the Fire Marshal, he observed that all of the burner knobs on the stove were in the same position, either all “off’ or all “on.” He further examined the burn patterns, noting that if the blaze had been caused by a grease fire on the stove, the cabinets directly above would have been consumed in the fire. Instead, they were merely damaged. He acknowledged that he did not know exactly how the fire started inside the refrigerator but indicated he suspected there had been a poor connection in the wiring that caused the wire to smolder until it ignited the highly combustible foam insulation inside the unit.

The former Deputy Chief of the New York City Fire Department asserted in his affidavit that the “fire damage to the area around the refrigerator when compared to that of the stove clearly shows the longer and heavier burn at the refrigerator,” indicating the fire originated there. He also stated that he had ruled out all other possible origins of the fire.

Upon review of these expert depositions and affidavit, we conclude that plaintiffs raised a triable question of fact by offering competent evidence which, if credited by the jury, was sufficient to rebut defendants’ alternative cause evidence. In other words, based on plaintiffs’ proof, a reasonable jury could conclude that plaintiffs excluded all other causes of the fire.

*44We therefore disagree with the Appellate Division’s characterization of plaintiffs’ submissions as equivocal. Plaintiffs’ experts consistently asserted that the fire originated in the upper right quadrant of the refrigerator and each contended the stove was not the source of the blaze. Both parties supported their positions with detailed, nonconclusory expert depositions and other submissions which explained the bases for the opinions.

Defendants contend that after they came forward with evidence suggesting an alternative cause of the fire, plaintiffs were foreclosed from establishing a product defect circumstantially but were then required to produce evidence of a specific defect to survive summary judgment. We reject this approach for two reasons. First, such an analysis would allow a defendant who offered minimally sufficient alternative cause evidence in a products liability case to foreclose a plaintiff from proceeding circumstantially without a jury having determined whether defendant’s evidence should be credited. Second, it misinterprets the court’s role in adjudicating a motion for summary judgment, which is issue identification, not issue resolution. Where causation is disputed, summary judgment is not appropriate unless “only one conclusion may be drawn from the established facts” (Kriz v Schum, 75 NY2d 25, 34 [1989]). That is not the case here where plaintiffs directly rebutted defendants’ submissions with competent proof specifically ruling out the stove as the source of the blaze. Because a reasonable jury could credit this proof and find that plaintiffs excluded all other causes of the fire not attributable to defendants, this case presents material issues of fact requiring a trial.

Accordingly, the order of the Appellate Division should be reversed, with costs, and the motion of defendants Sears, Roebuck and Co. and Whirlpool Corporation for summary judgment denied.

Chief Judge Kaye and Judges Smith, Ciparick, Wesley, Rosenblatt and Read concur.

Order reversed, etc.

TERNUS, Justice.

The United States District Court for the Northern District of Iowa has certified eight questions to this court arising out of a personal injury action filed by a smoker against several cigarette manufacturers. The certified questions address the nature and extent of the manufacturers’ liability under products liability, warranty and tort law. In general, our answers can be summarized as follows: (1) in a design defect products liability case, Iowa applies the test set forth in Restatement (Third) of Torts: Product Liability sections 1 and 2 (1998); (2) a civil conspiracy claim may be based on conduct that does not constitute an intentional tort; (3) a product manufacturer’s failure to warn or disclose material information will support a fraud claim by a customer only when disclosure is necessary to prevent a prior representation from being misleading; (4) a product manufacturer’s advertisements and statements do not constitute an undertaking so as to create a duty under Restatement (Second) of Torts section 323 (1965); and (5) a cigarette manufacturer has no warranty or tort liability to a smoker based on a manufacturing defect when the cigarettes smoked by the plaintiff were in the condition intended by the manufacturer.

I. Factual and Procedural Background.

The plaintiffs, Robert and DeAnn Wright, filed a petition against the defen*163dants, all cigarette manufacturers, alleging they had been damaged as a result of Robert’s cigarette smoking. (For the sake of simplicity, we will refer only to the plaintiff, Robert Wright, in the remainder of this opinion.) The specific claims made by the plaintiff include (1) negligence, (2) strict liability, (3) breach of implied warranty, (4) breach of express warranty, (5) breach of special assumed duty, (6) fraudulent misrepresentation, (7) fraudulent nondisclosure, and (8) civil conspiracy. The defendants filed a motion to dismiss that was largely overruled by the federal district court. See Wright v. Brooke Group Ltd., 114 F.Supp.2d 797, 838 (N.D.Iowa 2000).

Thereafter, the defendants asked the federal court to certify questions of law to the Iowa Supreme Court pursuant to Iowa Code section 684A.1 (2001). Concluding the case presented several questions of state law that are potentially determinative and as to which there is either no controlling precedent or the precedent is ambiguous, the district court certified eight questions to this court.

The questions certified are:

1. In a design defect products liability case, what test applies under Iowa law to determine whether cigarettes are unreasonably dangerous? What requirements must be met under the applicable test?

2. Under Iowa law, can Defendants rely on Comment i of § 402A of the Restatement (Second) of Torts to show that cigarettes are not unreasonably dangerous?

3. Under Iowa law, does the common knowledge of the health risks associated with smoking, including addiction, preclude tort and warranty liability of cigarette manufacturers to smokers because cigarettes are not unreasonably dangerous insofar as the risks are commonly known? If yes, then:

a. [During] what period of time would such knowledge be common?

b. Is there a duty to warn of the risks associated with smoking cigarettes in light of such common knowledge?

c. Is reliance on advertisements, statements or representations suggesting that there are no risks associated with smoking, including addiction, justifiable in light of such common knowledge?

4. Under Iowa law, can Plaintiffs bring a civil conspiracy claim arising out of alleged wrongful conduct that may or may not have been an intentional tort— i.e., strict liability for manufacturing a defective product or intentionally agreeing to. produce an unreasonably dangerous product?

5. Under Iowa law, can a manufacturer’s alleged failure to warn or to disclose material information give rise to a fraud claim when the relationship between a Plaintiff and a Defendant is solely that of a customer/buyer and manufacturer?

6. Does an “undertaking” arise under § 323 of the Restatement (Second) of Torts, as adopted in Iowa, by reason of a product manufacturer’s advertisements or statements directed to its customers?

7. Does Iowa law allow a Plaintiff to recover from a cigarette manufacturer under a manufacturing defect theory when the cigarettes smoked by Plaintiff were in the condition intended by the manufacturer?

8. Does Iowa law allow Plaintiff to recover from a cigarette manufacturer for breach of implied warranty of merchantability when the cigarettes smoked by Plaintiff were in the condition intended by the manufacturer and Plaintiff alleg*164es Defendants’ cigarettes are “substantially interchangeable”?

We will answer the questions in the order propounded.

II. In a Design Defect Products Liability Case, What Test Applies Under Iowa Law to Determine Whether Cigarettes Are Unreasonably Dangerous? What Requirements Must Be Met Under the Applicable Test?

A. Iowa law governing strict liability for defective products. The Iowa Supreme Court first applied strict liability in tort for a product defect in 1970, adopting Restatement (Second) of Torts section 402A (1965). Hawkeye-Sec. Ins. Co. v. Ford Motor Co., 174 N.W.2d 672, 684 (Iowa 1970). Section 402A provides:

Special Liability of Seller of Product for Physical Harm to User or Consumer:

(1) one who sells any product in a defective condition unreasonably dangerous to the user or consumer or to his property is subject to liability for physical harm thereby caused to the ultimate user or consumer, or to his property, if

(a) the seller is engaged in the business of selling such a product, and

(b) it is expected to and does reach the user or consumer without substantial change in the condition in which it is sold.

(2) The rule stated in Subsection (1) applies although

(a) the seller has exercised all possible care in the preparation and sale of his product, and

(b) the user or consumer has not bought the product from or entered into any contractual relation with the seller.

Restatement (Second) of Torts § 402A. Our purpose in adopting this provision was to relieve injured plaintiffs of the burden of proving the elements of warranty or negligence theories, thereby insuring “ ‘that the costs of injuries resulting from defective products are borne by the manufacturers that put such products on the market.’ ” Hawkeye-Sec. Ins. Co., 174 N.W.2d at 683 (citation omitted).

Consistent with this purpose we held that a plaintiff seeking to recover under a strict liability theory need not prove the manufacturer’s negligence. Id. at 684. Moreover, we concluded that application of strict liability in tort was not exclusive and did not “‘preclude liability based on the alternative ground of negligence, when negligence could be proved.’ ” Id. at 685 (citation omitted). Although Hawkeye-Se-curity was a manufacturing defect case, id. at 676-77, our opinion implied that strict liability in tort was applicable to design defects as well, id. at 684 (quoting authority that strict liability is applicable when “the defect arose out of the design or manufacture” of the product).

In Alter v. Rodgers Machinery Manufacturing Co., a design defect case, our court discussed in more detail the test to be applied in strict liability cases. 268 N.W.2d 830, 832 (Iowa 1978). In that case, the plaintiff asked the court to eliminate the “unreasonably dangerous” element of strict products liability, arguing that to require proof that the product was unreasonably dangerous injected considerations of negligence into strict liability, thwarting the purpose of adopting a strict liability theory. Id. at 833-34. We rejected the plaintiffs request to eliminate the “unreasonably dangerous” element, concluding the theories of strict liability and negligence were distinguishable:

In strict liability the plaintiffs proof concerns the condition (dangerous) of a product which is designed or manufactured in a particular way. In negligence the proof concerns the reasonableness of *165the manufacturer’s conduct in designing and selling the product as he did.

In strict liability the plaintiff takes the design as it was finalized in the finished product and shows it was both dangerous and that it was unreasonable to subject the user to this danger because the user would not contemplate the danger in the normal and innocent use of the product or consumption of the product. In negligence the plaintiff shows the manufacturer was unreasonable in designing the product as he did.

Id. at 835 (citation omitted).

These articulated distinctions were, however, somewhat obscured by this court’s explanation of the proof required in a strict liability case. Relying on comment i to section 402A, we held that a plaintiff seeking to prove a product was in a “defective condition unreasonably dangerous” must show that the product was “dangerous to an extent beyond that which would be contemplated by the ordinary consumer who purchases it, with the ordinary knowledge common to the community as to its characteristics.” Id. at 834 (quoting Restatement (Second) of Torts § 402A cmt. i). We went on, however, to discuss how the plaintiff is to prove the defective condition was unreasonably dangerous:

In order to prove that a product is unreasonably dangerous, the injured plaintiff must prove the product is dangerous and that it was unreasonable for such a danger to exist. Proof of unreasonableness involves a balancing process. On one side of the scale is the utility of the product and on the other is the risk of its use.

Whether the doctrine of negligence or strict liability is being used to impose liability the same process is going on in each instance, i.e., weighing the utility of the article against the risk of its use.

Id. at 835 (emphasis added). Two conclusions can be drawn from our discussion in Aller: (1) the legal principles applied in a strict liability case include both a consumer expectation or consumer contemplation test and a risk/benefit or risk/utility analysis; and (2) the risk/benefit analysis employed in a strict liability design defect case is the same weighing process as that used in a negligence case.

Since Aller, this court has varied in its application of the tests set forth in that decision, sometimes applying both tests and sometimes applying only the consumer expectation test. On the other hand, we have continued to equate the strict liability risk/benefit analysis used in a design defect case with that applied in a design negligence case.

In Chown v. USM Corp., 297 N.W.2d 218, 220 (Iowa 1980), a design defect case, we noted that proof of unreasonable danger was an essential element under both strict liability and negligence. We also observed there were two tests to determine this element, a consumer expectation test and a risk/benefit analysis. Chown, 297 N.W.2d at 220-21. This court then proceeded to apply both tests in deciding the trial court had not erred in ruling that the plaintiff failed to prove the essential element of unreasonable danger. Id. at 221. Finding no error, we held the absence of an “unreasonably dangerous” product was fatal to both the plaintiffs design negligence and strict liability design defect claims. Id.

In Fell v. Kewanee Farm Equipment Co., 457 N.W.2d 911, 916-18 (Iowa 1990), this court again applied both the consumer expectation and risk/benefit tests in a strict liability design defect case. Accord Mercer v. Pittway Corp., 616 N.W.2d 602, 619-20 (Iowa 2000) (applying both tests). In contrast, some of our cases appear to analyze the element of “unreasonably dan*166gerous” under the consumer expectation test alone. See Weyerhaeuser Co. v. Thermogas Co., 620 N.W.2d 819, 828 (Iowa 2000) (applying consumer expectation test without comment on risk/utility analysis); Maguire v. Pabst Brewing Co., 387 N.W.2d 565, 569-70 (Iowa 1986) (same).

One final development in products liability law in Iowa is worth mentioning before we address the precise issue in this case. In Olson v. Prosoco, 522 N.W.2d 284 (Iowa 1994), this court rejected the distinction between negligence and strict liability claims first articulated in Aller. Olson, 522 N.W.2d at 289. Examining a failure-to-warn case, we abandoned the analysis that differentiated strict liability from negligence on the basis that negligence focuses on the defendant’s conduct while strict liability focuses on the condition of the product. Id. We concluded that “[ijnevitably the conduct of the defendant in a failure to warn case becomes the issue,” and therefore, the produet/eonduct distinction had “little practical significance.” Id. Our ac-knowledgement that the test for negligence and strict liability were in essence the same led this court to discard the theory of strict liability in failure-to-warn cases and hold that such claims should be submitted under a theory of negligence only. Id.

With this abbreviated review of the current status of Iowa product liability law in mind, we turn now to the parties’ arguments on the question of the applicable test for determining whether cigarettes are unreasonably dangerous.

B. Arguments of parties. The parties disagree as to whether the consumer contemplation test and the risk/benefit analysis are alternative tests or whether both apply in all product defect cases. Assuming the tests are alternative, the parties also differ on which test applies to cigarette cases.

The defendants assert that only the consumer contemplation test of comment i to ’ section 402A should be used to determine whether cigarettes are unreasonably dangerous. Their desire for this test stems from their related argument that common knowledge of the risks of cigarette smoking precludes a finding that cigarettes are dangerous “to an extent beyond that which would be contemplated by the ordinary consumer.” Restatement (Second) of Torts § 402A cmt. i. The defendants argue that the risk/utility test should not be applied because it was designed for those products, unlike cigarettes, “about which the ordinary consumer would not normally have an expectation of safety or dangerousness.”

The plaintiff contends both the consumer contemplation and risk/utility tests apply in design defect cases to determine whether a product is unreasonably dangerous. Alternatively, he suggests this case presents an appropriate opportunity for the court to adopt the principles of law set forth in section 2 of Restatement (Third) of Torts: Product Liability [hereinafter “Products Restatement”]. As a final option, he argues that “[s]ince the cigarette companies disputed for decades that their products were dangerous, [cigarettes] would not be products for which consumers would normally have an expectation of safety or dangerousness decades in the past,” thus qualifying for the risk/utility test under the analytical scheme proposed by the defendants.

C. Discussion. In determining what test should be applied in assessing whether cigarettes are unreasonably dangerous, we are confronted with the anomaly of using a risk/benefit analysis for purposes of strict liability based on defective design that is identical to the test employed in proving negligence in product *167design. See Hillrichs v. Avco Corp., 478 N.W.2d 70, 75 (Iowa 1991) (noting, with respect to allegation of enhanced injury-due to a design defect, that standards applied in that case “make the strict liability claim depend on virtually the same elements of proof as are required to establish the negligence claim”), overruled on other grounds by Reed v. Chrysler Corp., 494 N.W.2d 224, 230 (Iowa 1992). This incongruity has drawn our attention once again to the “debate over whether the distinction between strict liability and negligence theories should be maintained when applied to a design defect case.” Lovick v. Wil-Rich, 588 N.W.2d 688, 698 (Iowa 1999). We are convinced such a distinction is illusory, just as we found no real difference between strict liability and negligence principles in failure-to-warn cases. See Olson, 522 N.W.2d at 289; Jones v. Hutchinson Mfg., Inc., 502 S.W.2d 66, 69-70 (Ky.1973) (finding no difference between standards of conduct under strict liability and negligence in design defect case: “In either event the standard required is reasonable care.”). See generally David Owen, Products Liability Law Restated, 49 S.C. L.Rev. 273, 286 (1998) (“It long has been an open secret that, while purporting to apply ‘strict’ liability doctrine to design and warnings cases, courts in fact have been applying principles that look remarkably like negligence.”) [hereinafter “Owen”]. Because the Products Restatement is consistent with our conclusion, we think it sets forth an intellectually sound set of legal principles for product defect cases.

Before we discuss these principles, we first explain our dissatisfaction with the consumer expectation test advocated by the defendants. As one writer has suggested, the consumer expectation test in reality does little to distinguish strict liability from ordinary negligence:

The consumer expectations test for strict liability operates effectively when the product defect is a construction or manufacturing defect.... An internal standard exists against which to measure the product’s condition — the manufacturer’s own design standard. In essence, a product flawed in manufacture frustrates the manufacturer’s own design objectives. Liability is imposed on manufacturers in these cases even if the manufacturer shows it acted reasonably in making the product....

When the claim of defect is based on the product’s plan or design, however, the consumer expectations test is inadequate. The test seems to function as a negligence test because a consumer would likely expect the manufacturer to exercise reasonable care in designing the product and using the technology available at that time.... Although the consumer expectations test purports to establish the manufacturer’s conduct is unimportant, it does not explain what truly converts it into a standard of strict liability.

Keith Miller, Design Defect Litigation in Iowa: The Myths of Strict Liability, 40 Drake L.Rev. 465, 473-74 (1991). We agree that the consumer contemplation test is inadequate to differentiate a strict liability design defect claim from a negligent design case. Cf. Olson, 522 N.W.2d at 289 (concluding there was no real difference between the tests used in negligent failure to warn and strict liability based on a failure to warn, noting “[i]nevitably the conduct of the defendant ... becomes the issue”). Consequently, any attempts to distinguish the two theories in the context of a defective design are in vain. That brings us to the Products Restatement, which reflects a similar conclusion by its drafters.

*168The Products Restatement demonstrates a recognition that strict liability is appropriate in manufacturing defect cases, but negligence principles are more suitable for other defective product cases. See 2 Dan B. Dobbs, The Law of Torts § 353, at 977 (2001) (“The effect ... of the Products Restatement is that strict liability is retained when it comes to product flaws, but negligence or something very much like it is the test of liability when it comes to design and warning defects.”) [hereinafter “Dobbs”]; Daniel Givelber, Cigarette Law, 73 Ind. L.J. 867, 885 (1998) (“Some thirty years after the Restatement’s [ (Second) of Torts] apparent embrace of strict products liability, the dominant rule in American law appears to be that manufacturers are only strictly liable when they make a product different and more dangerous from that intended.”). Accordingly, it “establishes] separate standards of liability for manufacturing defects, design defects, and defects based on inadequate instructions or warnings.” Products Restatement § 2 cmt. a, at 14. Initially, section 1 of the Products Restatement provides:

One engaged in the business of selling or otherwise distributing products who sells or distributes a defective product is subject to liability for harm to persons or property caused by the defect.

Products Restatement § 1, at 5. The “unreasonably dangerous” element of section 402A has been eliminated and has been replaced with a multi-faceted definition of defective product. This definition is set out in section 2:

A product is defective when, at the time of sale or distribution, it contains a manufacturing defect, is defective in design, or is defective because of inadequate instructions or warning. A product:

(a)contains a manufacturing defect when the product departs from its intended design even though all possible care was exercised in the preparation and marketing of the product;

(b) is defective in design when the foreseeable risks of harm posed by the product could have been reduced or avoided by the adoption of a reasonable alternative design by the seller or other distributor, or a predecessor in the commercial chain of distribution, and the omission of the alternative design renders the product not reasonably safe;

(c) is defective because of inadequate instructions or warnings when the foreseeable risks of harm posed by the product could have been reduced or avoided by the provision of reasonable instructions or warnings by the seller or other distributor, or a predecessor in the commercial chain of distribution, and the omission of the instructions or warnings renders the product not reasonably safe.

Products Restatement § 2, at 14.

The commentators give the following explanation for the analytical framework adopted in the Products Restatement:

In contrast to manufacturing defects, design defects and defects based on inadequate instructions or warnings are predicated on a different concept of responsibility. In the first place, such defects cannot be determined by reference to the manufacturer’s own design or marketing standards because those standards are the very ones that the plaintiffs attack as unreasonable. Some sort of independent assessment of advantages and disadvantages, to which some attach the label “risk-utility balancing,” is necessary. Products are not generically defective merely because they are dangerous. Many product-related accident costs can be eliminated only by excessively sacrificing product features that make products useful and desirable. Thus, the various trade-offs need to be *169considered in determining whether accident costs are more fairly and efficiently borne by accident victims, on the one hand, or, on the other hand, by consumers generally through the mechanism of higher product prices attributable to liability costs imposed by the courts on product sellers.

Products Restatement § 2 cmt. a, at 15-16. As we noted in Lovick, the Products Restatement has essentially “dropped the consumer expectation test traditionally used in the strict liability analysis and adopted a risk-utility analysis traditionally found in the negligence standard.” Lov-ick, 588 N.W.2d at 698; accord Products Restatement § 2 cmt. n, at 36 (“Regardless of the doctrinal label attached to a particular claim, design and warning claims rest on a risk-utility assessment.”); Owen, 49 S.C. L.Rev. at 285-86 (“Thus, the Products Liability Restatement grounds liability for design and warnings defects in the reasonableness-balancing-negligence concepts that properly dominate the law of tort”).

In addition, the Products Restatement does not place a conventional label, such as negligence or strict liability, on design defect cases.

The rules in this Section and in other provisions of this Chapter define the bases of tort .liability for harm caused by product defects existing at the time of sale or other distribution. The rules are stated functionally rather than in terms of traditional doctrinal categories. Claims based on product defect at time of sale or other distribution must meet the requisites set forth in Subsection (a), (b), or (c), or the other provisions in this Chapter. As long as these requisites are met, doctrinal tort categories such as negligence or strict liability may be utilized in bringing the claim.

Products Restatement § 2 cmt. n, at 34-35. We question the need for or usefulness of any traditional doctrinal label in design defect cases because, as comment n points out, a court should not submit both a negligence claim and a strict liability claim based on the same design defect since both claims rest on an identical risk-utility evaluation. Id. at 36. Moreover, to persist in using two names for the same claim only continues the dysfunction engendered by section 402A. Therefore, we prefer to label a claim based on a defective product design as a design defect claim without reference to strict liability or negligence.

D. Conclusion. In summary, we now adopt Restatement (Third) of Torts: Product Liability sections 1 and 2 for product defect cases. Under these sections, a plaintiff seeking to recover damages on the basis of a design defect must prove “the foreseeable risks of harm posed by the product could have been reduced or avoided by the adoption of a reasonable alternative design by the seller or other distributor, or a predecessor in the commercial chain of distribution, and the omission of the alternative design renders the product not reasonably safe.” Id. § 2(b); accord Hawkeye Bank v. State, 515 N.W.2d 348, 352 (Iowa 1994) (requiring “proof of an alternative safer design that is practicable under the circumstances” in negligent design case); Hillrichs, 478 N.W.2d at 75 (requiring “proof of an alternative safer design” under a theory of enhanced injury caused by a design defect).

III. Under Iowa Law, Can Defendants Rely on Comment i of § I02A of the Restatement (Second) of Torts to Show That Cigarettes Are Not Unreasonably Dangerous?

Comment i of section 402A addresses the “unreasonably dangerous” element of strict liability and sets forth the *170consumer contemplation test considered above. It discusses the necessity of proof that the product is dangerous “to an extent beyond that which would be contemplated by the ordinary consumer who purchases it, with the ordinary knowledge common to the community as to its characteristics.” Restatement (Second) of Torts § 402A cmt. i, at 352. In the course of this discussion, the comment states: “Good tobacco is not unreasonably dangerous merely because the effects of smoking may be harmful....” Relying on this statement, the defendants assert “[djesign defect claims involving cigarettes fail as a matter of law because cigarettes are not unreasonably dangerous under comment i”

Because we have abandoned section 402A and the requirement of unreasonably dangerous, comment i does not apply to the case before us. Therefore, the defendants cannot rely on the statement made in comment i pertaining to tobacco.

IV. Under Iowa Law, Does the Common Knowledge of the Health Risks Associated With Smoking, Including Addiction, Preclude Tort and Warranty Liability of Cigarette Manufacturers to Smokers Because Cigarettes Are Not Unreasonably Dangerous Insofar as the Risks Are Commonly Known?1

Our initial answer to this question is that our adoption of sections 1 and 2 of

the Products Restatement renders unnecessary any examination of the unreasonable dangerousness of cigarettes as that test is used in section 402A. Moreover, “consumer expectations do not constitute an independent standard for judging the defectiveness of product designs” under section 2. See Products Restatement § 2 cmt. g, at 27. Therefore, the common knowledge of consumers of the health risks associated with smoking does not necessarily preclude liability.

Although consumer expectations are not the sole focus in evaluating the defectiveness of a product under the Products Restatement, consumer expectations remain relevant in design defect cases. Comment g to section 2 states:

[Cjonsumer expectations about product performance and the dangers attendant to product use affect how risks are perceived and relate to forseeability and frequency of the risks of harm, both of which are relevant under Subsection (b). See Comment f Such expectations are often influenced by how products are portrayed and marketed and can have a significant impact on consumer behavior. Thus, although consumer expectations do not constitute an independent standard for judging the defectiveness of product designs, they may substantially influence or even be ultimately determinative on risk-utility balancing in judg-*171tag whether the omission of a proposed alternative design renders the product not reasonably safe.

Subsection (b) likewise rejects conformance to consumer expectations as a defense. The mere fact that a risk presented by a product design is open and obvious, or generally known, and that the product thus satisfies expectations, does not prevent a finding that the design is defective. But the fact that a product design meets consumer expectations may substantially influence or even be ultimately determinative on risk-utility balancing in judging whether the omission of a proposed alternative design renders the product not reasonably safe. It follows that, while disappointment of consumer expectations may not serve as an independent basis for allowing recovery under Subsection (b), neither may conformance with consumer expectations serve as an independent basis for denying recovery. Such expectations may be relevant in both contexts, but in neither are they controlling.

Id. § 2 cmt. g, at 27-28 (emphasis added). Thus, while consumer expectations are generally not determinative in a design defect case, they are one factor to be considered in deciding “whether an alternative design is reasonable and whether its omission renders a product not reasonably safe.” Id. § 2 cmt. f at 23.

Consumer knowledge also remains relevant to failure-to-warn claims.

In general, a product seller is not subject to liability for failing to warn or instruct regarding risks and risk-avoidance measures that should be obvious to, or generally known by, foreseeable product users. When a risk is obvious or generally known, the prospective addressee of a warning will or should already know of its existence. Warning of an obvious or generally known risk in most instances will not provide an effective additional measure of safety. Furthermore, warnings that deal with obvious or generally known risks may be ignored by users and consumers and may diminish the significance of warnings about non-obvious, not-generally-known risks. Thus, requiring warnings of obvious or generally known risks could reduce the efficacy of warnings generally. When reasonable minds may differ as to whether the risk was obvious or generally known, the issue is to be decided by the trier of fact.

Id. § 2 cmt.j, at 31.

In summary, consumer knowledge is merely one factor in assessing liability for design defects or for failure to warn of product risks. We cannot say at this stage of the proceedings prior to any factual determination of the common knowledge of consumers during the relevant time frame whether such knowledge would, as a matter of law, preclude liability under the principles set forth in the Products Restatement.

V. Under Iowa Law, Can Plaintiffs Bring a Civil Conspiracy Claim Arising Out of Alleged Wrongful Conduct That May or May Not Have Been an Intentional Tort— i.e., Strict Liability for Manufacturing a Defective Product or Intentionally Agreeing to Produce an Unreasonably Dangerous Product?

Under Iowa law, “[a] conspiracy is a combination of two or more persons by concerted action to accomplish an unlawful purpose, or to accomplish by unlawful means some purpose not in itself unlawful.” Basic Chems., Inc. v. Benson, 251 N.W.2d 220, 232 (Iowa 1977). Our court has also relied on the principles stated in the Restatement (Second) of Torts section 876 to set the parameters of this claim:

*172Under the Restatement, a person becomes subject to liability for harm caused by the tortious conduct of another when that person: (a) does a tortious act in concert with the other or pursuant to a common design with the other (traditional conspiracy)....

Ezzone v. Riccardi, 525 N.W.2d 388, 398 (Iowa 1994) (emphasis added) (citing Restatement (Second) of Torts § 876, at 315 (1979)). Under this theory of liability, “an agreement must exist between the two persons to commit a wrong against another.” Id. (emphasis added).

“Civil conspiracy is not in itself actionable; rather it is the acts causing injury undertaken in furtherance of the conspiracy [that] give rise to the action.” Basic Chems., 251 N.W.2d at 233; accord Adam v. Mt. Pleasant Bank & Trust Co., 387 N.W.2d 771, 773 (Iowa 1986). Thus, conspiracy is merely an avenue for imposing vicarious liability on a party for the wrongful conduct of another with whom the party has acted in concert. See John’s Insulation, Inc. v. Siska Constr. Co., 774 F.Supp. 156, 162 (S.D.N.Y.1991) (“Allegations of a civil conspiracy, therefore, are proper only for the purpose of establishing joint liability by co-participants in tortious conduct.”); 2 Dobbs § 340, at 936-37 (characterizing cases applying a civil conspiracy theory as employing a model of vicarious liability). Thus, the wrongful conduct taken by a co-conspirator must itself be actionable. See John’s Insular tion, Inc., 114: F.Supp. at 161 (“A claimant must plead specific wrongful acts which constitute an independent tort.”); Alexander & Alexander, Inc. v. B. Dixon Evan-der & Assocs., Inc., 88 Md.App. 672, 596 A.2d 687, 700 (1991) (“[T]he act (or means) need only be ‘of such a character as to create an actionable wrong.’ ” (citation omitted)); 16 Am.Jur.2d Conspiracy § 50, at 275-76 (1998) (“[I]f the acts alleged to constitute the underlying wrong provide no cause of action, then neither is there a cause of action for the conspiracy itself.”).

Although our cases applying a civil conspiracy theory involve agreements to commit an intentional tort, e.g., Revere Transducers, Inc. v. Deere & Co., 595 N.W.2d 751, 768 (Iowa 1999) (interference with contract); Ezzone, 525 N.W.2d at 392 (interference with contract); Adam, 387 N.W.2d at 775 (fraud); Basic Chems., 251 N.W.2d at 232 (unfair competition), our court has never held that a claim of civil conspiracy must be based on such an agreement. Moreover, our reliance on section 876 of the Restatement would seem to indicate an inclination to apply civil conspiracy whenever the underlying conduct was simply tortious. Although the Restatement (Second) of Torts takes no position on whether section 876 applies when the actor’s conduct involves strict liability,2 the comments to section 876 state “it is essential that the conduct of the actor be itself tortious.” See Restatement (Second) of Torts § 876 emt. c, at 316 (emphasis added); accord 2 Dobbs § 340, at 936 (“Conspiracy is not a tort in itself; it reflects the conclusion that each participant should be liable for the tortious course of conduct.” (Emphasis added.)). In addition, the comments include an illustration predicated on conduct that does not necessarily include an intent to do harm. See Restatement (Second) of Torts § 876 cmt. ⅞ illus. 1, at 316 (setting forth example involving co-conspirators who were racing on public highway).

*173Notwithstanding the lack of support in general legal authorities for a requirement that the tortious conduct of the actor be intentional, some jurisdictions require that a civil conspiracy claim be based on an intentional tort, not simple negligence. E.g., Sonnenreich v. Philip Morris Inc., 929 F.Supp. 416, 419 (S.D.Fla.1996); Campbell v. A.H. Robins Co., 615 F.Supp. 496, 50Ó (W.D.Wis.1985); Altman v. Fortune Brands, Inc., 268 A.D.2d 231, 701 N.Y.S.2d 615, 615 (2000); N. Am. Van Lines, Inc. v. Emmons, 50 S.W.3d 103, 116 (Tex.App.2001); accord 16 Am.Jur.2d Conspiracy § 51, at 278 (1998). These authorities suggest that since civil conspiracy is an intentional tort, it is illogical to conclude that persons can conspire to commit negligence. E.g., Sonnenreich, 929 F.Supp. at 419; Campbell, 615 F.Supp. at 497. We think this reasoning is faulty.

In Adcock v. Brakegate, Ltd., 164 I11.2d 54, 206 Ill.Dec. 636, 645 N.E.2d 888 (1995), the plaintiff sued his former employer and its successor, alleging that his employer, a manufacturer of asbestos, conspired with other manufacturers to suppress information about the hazards of asbestos exposure. 206 Ill.Dec. 636, 645 N.E.2d at 891-92. In rejecting the defendant’s argument that an action for civil conspiracy does not arise unless one of the conspirators .commits an intentional tort in furtherance of the conspiracy, the court stated:

While a civil conspiracy is based upon intentional activity, the element of intent is satisfied when a defendant knowingly and voluntarily participates in a common scheme to commit an unlawful act or a lawful act in an unlawful manner. There is no such thing as accidental, inadvertent or negligent participation in a conspiracy. A defendant who innocently performs an act which happens to fortuitously further the tortious purpose of another is not liable under the theory of civil conspiracy. A defendant who understands .the general objectives of the conspiratorial scheme, accepts them, and agrees ... to do its part to further those objectives, however, is liable as a . conspirator. Once a defendant knowingly agrees with another to commit an unlawful act or a lawful act in an unlawful manner, that defendant may be held liable for any tortious act committed in furtherance of the conspiracy, whether such tortious act is intentional or negligent in nature.

Id. at 894-95 (citations omitted).

We disagree with those courts that conclude an agreement to be negligent is a non sequitur. For example, the plaintiff in Adcock alleged “asbestos manufacturers éngaged in an industrywide conspiracy to conceal and affirmatively misstate the hazards associated with asbestos exposure” and “performed tortious acts in furtherance of the conspiracy.” Id. at 895. There is nothing illogical or nonsensical about this scenario: manufacturers agree to suppress information about their product for the lawful purpose of facilitating the sale of their product, and in effectuating this plan subject themselves to liability for failure to warn of the risks of using their product. So long as the underlying actionable conduct is of the type that one can plan ahead to do, it should not matter that the legal system allows recovery upon a mere showing of unreasonableness (negligence) rather than requiring an intent to harm.

Amicus curiae argue that to adopt this position will greatly extend the reach of civil conspiracy claims in the area of products liability. They contend that under this theory “[ejvery company that belongs to a trade association, industry group, or product advisory group would face conspiracy charges predicated on nothing more than the fact that it manufactured a product that had characteristics of those within that industry.” Under the *174principles announced today, however, we do not think liability could properly be imposed under the facts suggested by ami-cus curiae. Liability for civil conspiracy requires an agreement between the actor and the party sought to be held liable. See Ezzone, 525 N.W.2d at 398; Restatement (Second) of Torts § 876 cmt. a, at 316. An agreement sufficient to impose liability results only from a defendant’s knowing and voluntary participation in a common scheme to take action, lawful or unlawful, that ultimately subjects the actor to liability to another. See 16 Am.Jur.2d Conspiracy § 51, at 276 (stating there must be “a meeting of the minds”); see also McClure v. Owens Coming Fiberglas Corp., 188 I11.2d 102, 241 Ill.Dec. 787, 720 N.E.2d 242, 259 (1999) (“[Pjarallel conduct may serve as circumstantial evidence of a civil conspiracy among manufacturers of the same or similar products but is insufficient proof, by itself, of the agreement element of this tort.”). Consequently, a company’s mere membership in an industry group would not make that company liable for the tortious acts of other members of the group.

In summary, the plaintiff may base a claim of civil conspiracy on wrongful conduct that does not constitute an intentional tort. Such underlying acts must, however, be actionable in the absence of the conspiracy.

VI. Under Iowa Law, Can a Manufac- ■ turer’s Alleged Failure to Warn or to Disclose Material Information Give Rise to a Fraud Claim When the Relationship Between a Plaintiff and a Defendant Is Solely That of a Customer/Buyer and Manufacturer? 3

Under Iowa law, the failure to disclose material information can eonsti-tute fraud if the concealment is made “by a party under a duty to communicate the concealed fact.” Cornell v. Wunschel, 408 N.W.2d 369, 374 (Iowa 1987); see also Restatement (Second) of Torts § 557A, at 149 (1977) (stating that the tort of fraud may serve as a basis for the recovery of damages for physical harm to the person or property of one who justifiably relies on the defendant’s “fraudulent ... nondisclosure of a fact that it is [the defendant’s] duty to disclose ” (emphasis added)). The issue presented by the certified question is whether a manufacturer has a duty to communicate “material information” to the ultimate user of the manufacturer’s product.

In the past, this court has recognized a duty to disclose in situations where the plaintiff and the defendant were involved in some type of business transaction, such as buyer/seller or owner/contractor. See Clark v. McDaniel, 546 N.W.2d 590, 592-93 (Iowa 1996) (buyer and seller of used vehicle); Cornell, 408 N.W.2d at 376 (defendant represented wife in sale of hotel to the plaintiff); Kunkle Water & Elec., Inc. v. City of Prescott, 347 N.W.2d 648, 653-54 (Iowa 1984) (defendant to counterclaim contracted with counterclaim plaintiff to repair counterclaim plaintiffs water system). In such circumstances, we have held that an actionable misrepresentation may occur “when one with superior knowledge, dealing with inexperienced persons who rely on him or her, purposely suppresses the truth respecting a material fact involved in the transaction.” Kunkle Water & Elec., 347 N.W.2d at 653 (emphasis added); accord Cornell, 408 N.W.2d at 376. This principle is consistent with the Restatement’s imposition of a duty to disclose

*175facts basic to the transaction, if [the defendant] knows that the other is about to enter into it under a mistake as to them, and that the other, because of the relationship between them, the customs of the trade or other objective circumstances, would reasonably expect a disclosure of those facts.

Restatement (Second) of Torts § 551(2)(e), at 119.

This court has also held that a duty to disclose may arise from the “attendant circumstances,” such as a “ ‘contrivance intended to exclude suspicion and prevent inquiry.’ ” Wilden Clinic, Inc, v. City of Des Moines, 229 N.W.2d 286, 293 (Iowa 1975) (quoting 37 Am.Jur.2d Fraud and Deceit § 145 (1968)) (involving dispute between buyer and seller of land). This position is in accord with the Restatement (Second) of Torts, which provides:

One party to a business transaction is under a duty to exercise reasonable care to disclose to the other before the transaction is consummated,

(b) matters known to him that he knows to be necessary to prevent his partial or ambiguous statement of the facts from being misleading....

Restatement (Second) of Torts § 551(2)(b) (emphasis added); accord Laborers Local 17 Health & Benefit Fund v. Philip Morris, Inc., 7 F.Supp.2d 277, 290-91 (S.D.N.Y.1998); 2 Dobbs § 481, at 1375 (stating that an “[affirmative dut[y] of disclosure [is] imposed when ... the defendant has communicated a half-truth, that is, a partial or ambiguous statement that is misleading unless additional facts are disclosed”). A similar factual situation giving rise to a duty to disclose occurs when a party acquires information “that he knows will make untrue or misleading a previous representation that when made was true or believed to be so.” Restatement (Second) of Torts § 551(2)(c). A party must use reasonable care to disclose such subsequently acquired information to another party who has relied on the prior representation. Id.; Glassner v. R.J. Reynolds Tobacco Co., 223 F.3d 343, 352 (6th Cir.2000); Jones v. Am. Tobacco Co., 17 F.Supp.2d 706, 719 (N.D.Ohio 1998).

Whether a manufacturer owes a duty to disclose material information to a consumer turns, we think, on two issues: (1) is the nature of the relationship between a consumer and a manufacturer of the type to which such a duty should attach even in the absence of any direct dealing between the parties; and (2) does the duty of a manufacturer to a consumer encompass a general duty “to warn or to disclose material information” or is it limited to a duty to correct misleading statements made by the manufacturer? For reasons that follow, we conclude a manufacturer has a duty to a consumer under Restatement (Second) of Torts section 551(2)(b) to disclose “matters known to [the manufacturer] that [it] knows to be necessary to prevent [its] partial or ambiguous statement of the facts from being misleading” and under section 551(2)(c) to disclose subsequently acquired information that would prevent a prior statement from being false or misleading.

Iowa cases applying a fraud theory have typically involved a business transaction between the parties, a fact not present in the certified question submitted here. Generally there is no “dealing” between a manufacturer and the ultimate consumer of the manufacturer’s product. Thus, the communication between two parties giving rise to one party’s reliance on the other to disclose facts material to the first party’s decision to enter into the transaction is lacking. See Moore v. Fenex, Inc., 809 F.2d 297, 303 n. 2 (6th Cir.1987) (“We are aware of no case, nor has any been cited, *176where a party.has been liable for fraudulent nondisclosure that had no direct dealings with the plaintiff”)- But see Clark v. McDaniel, 546 N.W.2d 590, 592-94 (Iowa 1996) (holding used-car dealer liable to subsequent purchaser for fraudulent nondisclosure pursuant to Restatement (Second) of Torts § 533 (1977), which extends liability to third parties whom the defendant has reason to expect will hear and rely on misinformation).

On the other hand, there is. support in Iowa case law for the conclusion that the intentional tort of fraud is not necessarily limited to parties dealing directly with each other. In Markworth v. State Savings Bank, 212 Iowa 954, 237 N.W. 471 (1931), this court noted that an action for fraud “can only be brought by the one to whom the fraudulent representations were made.” 212 Iowa at 960, 237 N.W. at 474. In explaining this limitation, however, the court quoted “approvingly” from a noted treatise on torts that belied such a narrow application of the tort:

“No one has a right to accept and rely upon the representations of others but those to influence whose action they were made. * ⅝ * When statements are made for the express purpose of influencing the action of another, it is to be assumed they are made deliberately, and after due inquiry, and it is no hardship to hold the party making them to their truth. But he is morally accountable to no person whomsoever but the very person he seeks to influence.”

Id. at 960-61, 237 N.W. at 474 (citation omitted). We. conclude from this discussion that what is really important is that the statements were made for the purpose of influencing the action of another. • The fact that this element is usually found in transactions where the parties deal directly with one another does not mean that the same goal of influencing another’s action cannot be present in business transactions that do not involve direct contact between the plaintiff and the defendant. See Small v. Lorillard Tobacco Co., 176 Misc.2d 413, 672 N.Y.S.2d 601, 611 (Sup. Ct.1997) (holding that manufacturer could be held liable for fraud where the misrepresentations were “made to the public at large for the purpose of influencing the action of anyone who may act upon those representations”); Williams v. Philip Moms Inc., 182 Or.App. 44, 48 P.3d 824, 832 (2002) (holding that smoker was required to prove he was “within a class of people whom defendant [cigarette manufacturer] intended to be recipients of and to rely on the [misleading statements]”). We hold, therefore, that a manufacturer who makes'statements for the purpose of influencing the purchasing decisions of consumers has a duty to disclose sufficient information so as to prevent the statements made from being misleading, as well as a duty to reveal subsequently acquired information that prevents a prior statement, true when made, from being misleading.

We decline to extend the duty of disclosure in this context to a general duty to warn, or a duty to disclose under Restatement section 551(2)(e). See Estate of White ex rel. White v. R.J. Reynolds Tobacco Co., 109 F.Supp.2d 424, 431 (D.Md. 2000) (refusing to impose duty to disclose based on mere relationship of manufacturer and buyer); Connick v. Suzuki Motor Co., 174 I11.2d -482, 221 Ill.Dec. 389, 675 N.E.2d 584, 593 (1996) (same). See generally Restatement (Second) of Torts § 551(2)(e) (imposing a duty to disclose “facts basic to the transaction” when such disclosure would be expected based on the nature of the transaction). Principles of products liability law define the duties of disclosure owed by a manufacturer. to a consumer arising out of their relationship as such.

*177In summary, a manufacturer’s failure to warn or to disclose material information does not give rise to a fraud claim when the relationship between a plaintiff and a defendant is solely that of a customer/buyer and manufacturer with two exceptions. Those exceptions are limited to instances where the manufacturer (1) has made misleading statements of fact intended to influence consumers, or (2) has made true statements of fact designed to influence consumers and subsequently acquires information rendering the prior statements untrue or misleading. See Restatement (Second) of Torts § 551(2)(b), (c). Under these circumstances, a manufacturer’s failure to disclose material information that would prevent his statement of the facts from being misleading can give rise to a fraud claim.4

VII. Does an “Undertaking” Arise Under § 328 of the Restatement (Second) of Torts, as Adopted in Iowa, by Reason of a Product Manufacturer’s Advertisements or Statements Directed to Its Customers?

Restatement (Second) of Torts section 323 has been characterized as defining the liability of a “good Samaritan.” See, e.g., Good v. Ohio Edison Co., 149 F.3d 413, 420 (6th Cir.1998); Gunsalus v. Celotex Corp., 674 F.Supp. 1149, 1157 (E.D.Pa.1987). It provides:

One who undertakes, gratuitously or for consideration, to render services to another which he should recognize as necessary for the protection of the other’s person or things, is subject to liability to the other for physical harm resulting from his failure to exercise reasonable care to perform his undertaking, if

(a) his failure to exercise such care increases the risk of such harm, or

(b) the harm is suffered because of the other’s reliance upon the undertaking.

Restatement (Second) of Torts § 323; see also Jain v. State, 617 N.W.2d 293, 299-300 (Iowa 2000) (discussing requirements for claim made under section 323).

Preliminarily, it seems obvious from the text of this provision that not every statement made by a manufacturer, whether in an advertisement or otherwise, could constitute an undertaking under section 323. Only when the advertisement or statement indicates that the manufacturer intends to render services to another that are necessary for the other’s protection is liability under section 323 even possible. Thus, we agree with the United States Court of Appeals for the Third Circuit that a manufacturer’s mere marketing of its product does not constitute an “undertaking to inform the public about the known risks of its products.” Steamfitters Local Union No. 120 Welfare Fund v. Philip Morris, Inc., 171 F.3d 912, 936 (3d Cir. 1999).

Even though our discussion could end here, we assume, based on the allegations in the petition, that the certified question contemplates the advertisement or statement made by the product manufacturer is something more than mere marketing. Thus, we will proceed with the understanding that the advertisement or statement *178this court is asked to consider is one similar to that alleged by the plaintiff in his petition. Here, the plaintiff alleges that the defendants promised to “report honestly and competently on all reseai-ch regarding smoking and health regarding their tobacco products through their public pronouncements.”

We do not think the defendants’ statements that they would report on the results of their research into the health effects of cigarette smoking was an undertaking to render a service to its customers. As one court has concluded in rejecting section 323 liability based on similar statements by tobacco companies, the defendants, by making these statements, did not undertake “to do anything specific for any particular person or entity.” Ky. Laborers Dist. Council Health & Welfare Trust Fund v. Hill & Knowlton, Inc., 24 F.Supp.2d 755, 774 (W.D.Ky.1998) (considering manufacturers’ public expression of “interest in the public health” and pledge of “resources to assist the scientific and public health communities with tobacco research”). Other courts are in accord with this result. See Serv. Employees Inti Union Health & Welfare Fund v. Philip Morris, Inc., 83 F.Supp.2d 70, 93 (D.D.C.1999), rev’d on other grounds, 249 F.3d 1068 (D.C.Cir. 2001) (rejecting section 323 liability based on similar statements made by cigarette manufacturers to the general public, ruling such statements “must be made directly to the [smoker], not to the general public through advertisements”); Ark. Carpenters’ Health & Welfare Fund v. Philip Moms Inc., 75 F.Supp.2d 936, 944 (E.D.Ark.1999) (holding that similar statements by cigarette manufacturer were insufficient to support liability under section 323); Mass. Laborers’ Health & Welfare. Fund v. Philip Morris, Inc., 62 F.Supp.2d 236, 245-46 (D.Mass.1999) (dismissing section 323 claim brought by employee health benefit plan to recover expenses it paid for its participants’ smoking-related health care, stating “the ‘relationship’ between sellers of a product and purchasers of that product” is not an appropriate basis for section 323 liability); Gunsalus, 674 F.Supp. at 1157 (granting summary judgment on section 323 claim, stating tobacco company’s public pledge of “aid and assistance to the research effort into all phases of tobacco use and health” did not “constitute an assumption of a duty to [individual smokers] to perform research and inform [them] of all dangers of cigarette smoking”). We conclude statements by manufacturers such as those alleged in the plaintiffs petition are not an “undertaking” within the scope of section 323.

VIII. Does Iowa Law Allow a Plaintiff to Recover From a Cigarette Manufacturer Under a Manufacturing Defect Theory When the Cigarettes Smoked by Plaintiff Were in the Condition Intended by the Manufacturer?

Under the principles set forth in the Products Restatement adopted today, “[a] product is defective when, at the time of sale or distribution, it contains a manufacturing defect....” Products Restatement § 2. A product “contains a manufacturing defect when the product departs from its intended design even though all possible care was exercised in the preparation and marketing of the product.” Id. § 2(a) (emphasis added). Clearly, then, under Iowa law, a plaintiff may not recover from a cigarette manufacturer under a manufacturing defect theory when the cigarettes smoked by the plaintiff were in the condition intended by the manufacturer.

Although the answer to the certified question is clear under the law set out in the Products Restatement, many courts have reached the same conclusion in applying the principles of Restatement (Second) of Torts. See, e.g., Wheeler v. Ho Sports Inc., 232 F.3d 754, 757 (10th Cir.2000) (“A *179product is defective in manufacture if it ‘deviates in some material way from its design or performance standards. The issue is whether the product was rendered unsafe by an error in the manufacturing process.’ Errors in process are often established by showing that a product, as produced, failed to conform with the manufacturer’s specifications.” (Citations omitted.)); In re Temporomandibular Joint (TMJ) Implants Prods. Liab. Litig., 97 F.3d 1050, 1055 n. 4 (8th Cir.1996) (“‘A manufacturing defect exists only where an item is substandard when compared to other identical units off of the assembly line.’ ”); Guilbeault v. R.J. Reynolds Tobacco Co., 84 F.Supp.2d 263, 280 (D.R.I. 2000) (“To establish a manufacturing defect, ‘a plaintiff must show a product defect caused by a mistake or accident in the manufacturing process.’ ” (Citation omitted.)); Stoffel v. Thermogas Co., 998 F.Supp. 1021, 1033 (N.D.Iowa 1997) (“ ‘A manufacturing defect ... results when a mistake in manufacturing renders a product that is ordinarily safe dangerous so that it causes harm.’ ” (Citation omitted.)) (applying Iowa law); 2 Dobbs § 362, at 1002 (“The plaintiff may show a [manufacturing] defect by direct evidence that points to the defect and identifies it as a departure from the defendant’s intended design.”).

IX. Does Iowa Law Allow Plaintiff to Recover From a Cigarette Manufacturer for Breach of Implied Warranty of Merchantability When the Cigarettes Smoked by Plaintiff Were in the Condition Intended by the Manufacturer and Plaintiff Alleges Defendants’ Cigarettes Are “Substantially Interchangeable”?

Because the implied warranty of merchantability is statutory, we begin our dis-mission of this issue with a reference to the governing act:

1. Unless excluded or modified (section 554.2316), a warranty that the goods shall be merchantable is implied in a contract for their sale if the seller is a merchant with respect to goods of that kind....

2. Goods to be merchantable must be at least such as

a. pass without objection in the trade under the contract description; and

b. in the case of fungible goods, are of fair average quality within the description; and

c. are fit for the ordinary purposes for which such goods are used; and

d. run, within the variations permitted by the agreement, of even kind, quality and quantity within each unit and among all units involved; and

e. are adequately contained, packaged, and labeled as the agreement may require; and

f. conform to the promises or affirmations of fact made on the container or label if any.

Iowa Code § 554.2314 (1999).

The plaintiff claims the cigarettes sold by the defendants were not “fit for the ordinary purposes for which such goods are used” because the cigarettes were carcinogenic and addictive. See id. § 554.2314(2)(e).5 He argues that a design defect could infect an entire product line, thereby rendering the product unmer-chantable, even though the product is in the condition intended by the manufacturer and conforms to similar products.

*180The defendants assert that “when a product is manufactured as intended and is like other products of that type, there is no breach of the implied warranty of merchantability.” If a health risk associated with use of a product renders the product unmerchantable, contend the defendants, then warranty claims could be brought against manufacturers “of butter, meat, and alcohol, not to mention bicycles, ladders, and knives, precisely because they all carry a risk of disease or injury.”

In reviewing case law from other jurisdictions, we find support for both views. Courts have held that a product that is unreasonably dangerous or lacks adequate warning is likewise not fit for ordinary use. E.g., Hill v. Searle Labs., 884 F.2d 1064, 1070 n. 10 (8th Cir.1989) (“[IJnadequate warning can be evidence of a breach of warranty on the part of a manufacturer.”); Bly v. Otis Elevator Co., 713 F.2d 1040, 1045 (4th Cir.1983) (“A manufacturer may breach its implied warranty of merchantability by failing to warn or instruct concerning dangerous propensities or characteristics of a product even if that product is flawless in design and manufacture.”); Pritchard v. Liggett & Myers Tobacco Co., 295 F.2d 292, 296, 297 n. 14 (3d Cir.1961) (reversing dismissal of claim for breach of implied warranty of merchantability based on allegation that cigarettes were unfit because they caused physical injury to the smoker, notwithstanding lack of allegation that the cigarettes “smoked by plaintiff were not of the same quality as those generally sold”); Kyte v. Philip Morris Inc., 408 Mass. 162, 556 N.E.2d 1025, 1029 (1990) (denying summary judgment on plaintiffs breach of implied warranty claim based upon an alleged design defect, not in all cigarettes, but in Marlboro and Parliament cigarettes in particular that made those cigarettes “inherently carcinogenic and addictive”). In contrast, other courts have rejected the argument that an unreasonably dangerous product for purposes of strict liability is per se unmerchantable. E.g., Spain v. Brown & Williamson Tobacco Corp., 230 F.3d 1300, 1310 (11th Cir. 2000) (ruling that complaint alleging that cigarettes “were unfit for the ordinary purpose for which they are used because they caused cancer, making them unreasonably dangerous” did not “state a claim for breach of an implied warranty of merchantability”); Green v. Am. Tobacco Co., 409 F.2d 1166, 1166 (5th Cir.1969) (affirming judgment for cigarette manufacturer on breach of implied warranty claim, holding that warranty was not breached where there was no proof that cigarettes were adulterated); Tompkins v. R.J. Reynolds Tobacco Co., 92 F.Supp.2d 70, 94 (N.D.N.Y.2000) (dismissing implied warranty claim based on allegation that all cigarettes are carcinogenic, noting that “warranty of fitness for ordinary purposes ‘provides for a minimal level of quality’ ” (citation omitted)); Ark. Carpenters’ Health & Welfare Fund, 75 F.Supp.2d at 945 (holding plaintiff had failed to state a claim for breach of the implied warranty of merchantability based on allegation that “a typical cigarette, like all cigarettes, is ‘generally defective’ ”); Shell v. Union Oil Co., 489 So .2d 569, 571-72 (Ala.1986).

Although this court has not addressed the precise issue presented in the certified question, we think the answer lies in the interrelationship of warranty claims and tort product-defect claims, an issue we have considered. Almost twenty years ago, we observed that a warranty of merchantability “is based on a purchaser’s rea*181sonable expectation that goods ... will be free of significant defects and will perform in the way goods of that kind should perform.” Van Wyk v. Norden Labs., Inc., 345 N.W.2d 81, 84 (Iowa 1984) (emphasis added). More recently, this court has held that proof of a “serious product defect” was sufficient to support submission of strict liability and breach of warranty theories. Ballard v. Amana Soc’y, Inc., 526 N.W.2d 558, 562 (Iowa 1995). Notwithstanding a shared focus on defects, warranty claims have been distinguished from strict liability claims on the ground that “ ‘defects of suitability and quality are redressed through contract actions and safety hazards through tort actions.’ ” Am. Fire & Cas. Co. v. Ford Motor Co., 588 N.W.2d 437, 439 (Iowa 1999) (citations omitted); cf. Shell, 489 So.2d at 571 (“The implied warranty mandated by this section of the U.C.C. is one of commercial fitness and suitability.... That is to say, the U.C.C. does not impose upon the seller the broader obligation to warrant against health hazards inherent in the use of the product when the warranty of commercial fitness has been complied with. Those injured by the use of or contact with such a product, under these circumstances, must find their remedy outside the warranty remedies afforded by the U.C.C.”). Despite this distinction, we have found no error in submitting personal injury claims under both strict liability and breach of warranty theories. See Mercer, 616 N.W.2d at 621. In contrast, where only economic loss is alleged, recovery is limited to warranty claims. E.g., Tomka v. Hoechst Celanese Corp., 528 N.W.2d 103, 107 (Iowa 1995) (affirming dismissal of negligence and strict liability claims in case alleging purely economic injuries).

Although this court has approved submission of both theories in personal injury cases, we have noted the same evidence sufficient to support a negligence claim based on product defects is likewise adequate to support a breach-of-implied-warranty claim. Mercer, 616 N.W.2d at 621. Similarly, this court has stated that while strict liability, negligence, and breach of warranty are “distinct theor[ies] of recovery, the same facts often give rise to all three claims.” Lovick, 588 N.W.2d at 698.

As this review of our case law reveals, we have distinguished product claims premised on tort theories from product claims grounded on warranty theories on the basis of the damages sought rather than on the basis of the nature of the wrongful conduct. And, although we have limited cases involving only economic loss to warranty theories, personal injury plaintiffs are permitted to seek recovery under tort and warranty theories that in essence allege the same wrongful acts. We conclude, therefore, that under Iowa law a seller’s warranty that goods are fit for the ordinary purposes for which such goods are used gives rise to the same obligation owed by manufacturers under tort law with respect to the avoidance of personal injury to others.

The Products Restatement is consistent with this position. It suggests that cases involving harm to persons should satisfy the definition of product defect under section 2, whether the claim is brought under a theory of implied warranty of merchantability or under a tort theory. Products Restatement § 2 cmt. n, at 35; accord Vassallo v. Baxter Healthcare Corp., 428 Mass. 1, 696 N.E.2d' 909, 923 (1998) (adopting Products Restatement test for failure-to-warn claim based on breach of implied warranty of merchantability); cf. 1 James J. White and Robert S. Summers, Uniform Commercial Code § 9.8, at 521 (4th ed.1995) (stating authors’ belief that merchantability standard and tort standard for “defective condition” un*182der section 402A “are interchangeable”). We think this suggestion reflects current Iowa law: conduct that gives rise to a warranty claim based on fitness for ordinary purposes mirrors conduct that gives rise to tort liability for a defective product. Thus, warranty liability under section 554.2314(2)(c) requires proof of a product defect as defined in Products Restatement section 2.

Having defined the nature of the conduct that violates a warranty of merchantability, we now turn to the question before us: can a cigarette manufacturer be liable for breach of the implied warranty of merchantability when the cigarettes smoked by the plaintiff were in the condition intended by the manufacturer and the plaintiff alleges the defendants’ cigarettes are “substantially interchangeable”? If the defect alleged by the plaintiff is a manufacturing defect, see Products Restatement § 2(a), then the answer is “no” for the same reasons that we have previously held that a plaintiff may not recover from a cigarette manufacturer under a manufacturing defect theory when the cigarettes smoked by the plaintiff were in the condition intended by the manufacturer. Obviously, the fact that the cigarettes were in the condition intended by the manufacturer would not preclude recovery under an implied warranty theory where the defect alleged arises from a defective design or inadequate instructions or warnings. See Products Restatement § 2(b), (c).

X. Summary.

Our answers to the certified questions can be summarized as follows:

1.In a design defect products liability case, what test applies under Iowa law to determine whether cigarettes are unreasonably dangerous? What requirements must be met under the applicable test?

Answer: The test and requirements of Restatement (Third) of Torts: Product Liability sections 1-2 (1998) apply.

2. Under Iowa law, can the defendants rely on comment % of section 402A of the Restatement (Second) of Torts to show that cigarettes are not unreasonably dangerous?

Answer: Because Iowa has abandoned section 402A and the requirement of unreasonably dangerous, the defendants cannot rely on the statement made in comment i pertaining to tobacco.

3. Under Iowa law, does the common knowledge of the health risks associated with smoking, including addiction, preclude tort and warranty liability of cigarette manufacturers to smokers because cigarettes are not unreasonably dangerous insofar as the risks are commonly known?

If yes, then:

a. During what period of time would such knowledge be common?

b. Is there a duty to warn of the risks associated with smoking cigarettes in light of such common knowledge?

c. Is reliance on advertisements, statements or representations suggesting that there are no risks associated with smoking, including addiction, justifiable in light of such common knowledge?

Answer: Generally speaking, consumer knowledge is merely one factor in assessing liability for design defects or for failure to warn of product risks. The remainder of this question calls for factual determinations that are beyond the scope of a certified-question proceeding. In the absence of a factual finding with respect to the common knowledge of consumers during the relevant time frame, we cannot determine whether *183such knowledge would, as .a matter of law, preclude liability under the principles set forth in the Products Restatement.

4. Under Iowa law, can a plaintiff bring a civil conspiracy claim arising out of alleged wrongful conduct that may or may not have been an intentional tort— i.e., strict liability for manufacturing a defective product or intentionally agreeing to produce an unreasonably dangerous product?

Answer: Yes, a plaintiff may base a civil conspiracy claim on wrongful conduct that does not constitute an intentional tort.

5. Under Iowa law, can a manufacturer’s alleged failure to warn or to disclose material information give rise to a fraud claim when the relationship between a plaintiff and a defendant is solely that of a customer/buyer and manufacturer? Answer: Yes, but only when disclosure is required (1) to correct misleading statements of fact made by the manufacturer with the intent to influence consumers, or (2) to correct statements of fact made by the manufacturer to influence consumers that were true when made but become untrue or misleading in light of subsequently acquired information.

6. Does an “undertaking” arise under section 323 of the Restatement (Second) of Torts, as adopted in Iowa, by reason of a product manufacturer’s advertisements or statements directed to its customers?

Answer: Not within the factual parameters presented by this case.

7. Does Iowa law allow a plaintiff to recover from a cigarette manufacturer under a manufacturing defect theory when the cigarettes smoked by the plaintiff were in the condition intended by the manufacturer?

Answer: No.

8.Does Iowa law allow a plaintiff to recover from a cigarette manufacturer for breach of implied warranty of merchantability when the cigarettes smoked by the plaintiff were in the condition intended by the manufacturer and the plaintiff alleges the defendants’ cigarettes are “substantially interchangeable”?

Answer: If the breach is based on a manufacturing defect, recovery is not allowed. If the breach is based on a defective design or inadequate instructions or warnings, recovery is not precluded under the stated facts.

CERTIFIED QUESTIONS ANSWERED.

CALABRESI, Circuit Judge.

I. BACKGROUND

Luis Liriano, a seventeen-year-old. employee in the meat department at Super Associated grocery store (“Super”), was injured on the job in September 1993 when he was feeding meat into a commercial meat grinder whose safety guard had been removed. His hand was caught in the “worm” that grinds the meat; as a result, his right hand and lower forearm were amputated.

The meat grinder was manufactured and sold in 1961 by Hobart Corporation (“Hobart”). At the’ time of the sale, it had an affixed safety guard that prevented the user’s hands from coming into contact with the feeding tube and the grinding “worm.” No warnings were placed on the machine or otherwise given to indicate that it was dangerous to operate the machine without the safety guard in place. Subsequently, Hobart became aware that a significant number of purchasers of its meat grinders had removed the safety guards. And in 1962, Hobart began issuing warnings on its meat grinders concerning removal of the safety guard.

There is no dispute that, when Super acquired the grinder, the safety guard was intact. It is also not contested that, at the time of Liriano’s accident, the safety guard had been removed. There is likewise no doubt that Hobart actually knew, before the accident, that removals of this sort were occurring and that use of the machine without the safety guard was highly dangerous. And Super does not question that the removal of the guard took place while the grinder was in its possession.

Liriano sued Hobart under theories of negligence and strict products liability for, inter alia, defective product design and failure to warn. He brought his claims in the Supreme Court, Bronx County, New York. Hobart removed the ease to the United States District Court for the Southern District of New York, and also impleaded Super as a third-party defendant, seeking indemnification and/or contribution. The District Court (Shira A. Seheindlin, Judge) dismissed all of Liriano’s claims except those based on failure to warn.

Following trial, the jury concluded that the manufacturer’s failure to warn was the proximate cause of Liriano’s injuries and appor*126tioned liability 5% to Hobart and 95% to Super. On partial retrial, limited to the extent of Liriano’s responsibility, the jury assigned him 33 1/3% of the responsibility. On appeal, Hobart and Super argue, inter alia, that the question of whether Hobart had a duty to warn Liriano should have been decided in their favor by the court, as a matter of law. It is this question that gives rise to the current certification.

II. DISCUSSION

A. Applicable New York Law

It is well-settled under New York lavs'- that a manufacturer is under a duty to use reasonable care in designing its product so that it will be safe when “used in the manner for which the product was intended, as well as unintended yet reasonably foreseeable use.” Micallef v. Miehle Co., 39 N.Y.2d 376, 385-86, 348 N.E.2d 571, 577, 384 N.Y.S.2d 115, 121 (1976) (citations omitted). It is equally well-settled in New York that manufacturers have a duty to warn users of foreseeable dangers inherent in their products. See Rastelli v. Goodyear Tire & Rubber Co., 79 N.Y.2d 289, 297, 591 N.E.2d 222, 225, 582 N.Y.S.2d 373, 376 (1992); McLaughlin v. Mine Safety Appliances Co., 11 N.Y.2d 62, 68, 181 N.E.2d 430, 433, 226 N.Y.S.2d 407, 411 (1962); Bukowski v. CooperVision Inc., 185 A.D.2d 31, 33, 592 N.Y.S.2d 807, 808 (3d Dep’t 1993).

In Robinson v. Reed-Prentice Division, 49 N.Y.2d 471, 403 N.E.2d 440, 426 N.Y.S.2d 717 (1980), the New York Court of Appeals in effect removed a set of product liability cases from the Micallef analysis of “intended” and “reasonably foreseeable use.” The Robinson case itself involved a machine designed with a safety shield that could not be kept in an open (unprotecting) position due to a sophisticated interlock system. This interlock was designed to prevent the machine from operating unless its safety shield was in a closed (protecting) position. See id. at 476-77, 403 N.E.2d at 441-42, 426 N.Y.S.2d at 718-19. The plaintiffs employer, however, cut holes in the safety shield so that the machine would still operate (without the protections of the safety shield). See id. at 477, 403 N.E.2d at 442, 426 N.Y.S.2d at 719. In other words, the employer bypassed the safety devices of the shield and the interlocking safety system.

The New York Court of Appeals held that a manufacturer of a product may not be held liable “either on a strict products liability or negligence cause of action, where, after the product leaves the possession and control of the manufacturer, there is a subsequent .modification which substantially alters the product and is the proximate cause of plaintiffs injuries.” Id. at 475, 403 N.E.2d at 441, 426 N.Y.S.2d at 718. “Material alterations at the hands of a third party which work a substantial change in the condition in which the product was sold by destroying the functional utility of a key safety feature, however foreseeable that modification may have been, are not within the ambit of a manufacturer’s responsibility.” Id. at 481, 403 N.E.2d at 444, 426 N.Y.S.2d at 721.1

Robinson, though never overruled, has not been left undisturbed. Thus in Cover v. Cohen 61 N.Y.2d 261, 461 N.E.2d 864, 473 N.Y.S.2d 378 (1984), decided four years after Robinson, the Court of Appeals not only reaffirmed a manufacturer’s duty to warn purchasers of dangers in the product, but clearly held that this duty on the part of the manufacturer to warn can continue even after the original sale:

A manufacturer ... may, however, incur liability for failing to warn concerning dangers in the use of a product which come to his attention after manufacture or sale, through advancements in the state of the art, with which he is expected to stay abreast, or through being made aware of later accidents involving dangers in the *127 product of which warning should he given to users.

Id. at 274-75, 473 N.Y.S.2d 378, 461 N.E.2d 864, 461 N.E.2d at 871, 473 N.Y.S.2d at 385 (citations omitted) (emphasis added).2

Six years after Robinson, moreover, the Court of Appeals qualified Robinson in another way and declined to hold that all disablements of safety devices constitute subsequent modifications precluding a manufacturer’s liability. In Lopez v. Precision Papers, Inc., 67 N.Y.2d 871, 492 N.E.2d 1214, 501 N.Y.S.2d 798 (1986), the court held that a disablement does not necessarily foreclose liability where safeguards can be easily removed and where such removal thereby increases the efficacy of the product. The plaintiff in Lopez, a forklift operator, was severely injured when a large roll of paper fell from a wooden pallet on the machine he was operating and hit him on the head. The plaintiff sued the forklift manufacturer, alleging certain design defects, including an easily removable overhead guard. See Lopez v. Precision Papers, Inc., 107 A.D.2d 667, 667-68, 484 N.Y.S.2d 585, 586-87 (2d Dep’t 1985), aff'd, 67 N.Y.2d 871, 492 N.E.2d 1214, 501 N.Y.S.2d 798 (1986). The trial court granted partial summary judgment to the manufacturer, reasoning that “a manufacturer may not be held liable for the negligent alteration of the product by a user, even if the alteration is foreseeable.” Id. at 668, 484 N.Y.S.2d at 587.

The Appellate Division reversed,3 holding that Robinson, “the ease relied upon by Special Term, does not, as a matter of law, bar plaintiffs’ claim.” Id. Robinson, the court said, was a case in which “the modification was so substantial that it permanently destroyed the functional utility of a safety gate.” Id. at 669, 484 N.Y.S.2d at 587. In Lopez, instead, the safety device was easily removed and the removal made the product more functional. See id. 4 Under the circumstances, the court held, a jury could decide “the forklift’s intended purposes.” Id. at 669, 484 N.Y.S.2d at 587-88. In other words, if the jury found that removability of the safety guard was part of the forklift’s design, then the guard’s removal did not constitute a subsequent modification of the product.

The Court of Appeals affirmed the Appellate Division. It held that a manufacturer may, under some circumstances, be liable under a design defect theory even though the removal of a safety feature proximately caused the injury. But in order to hold a defendant-manufacturer liable for injuries under Lopez on such a theory, a plaintiff has to prove that the product “was purposefully manufactured to permit its use without the safety guard.” Lopez, 67 N.Y.2d at 873, 492 N.E.2d at 1215, 501 N.Y.S.2d at 799.

*128 B. Unsettled, Issues of Law

The further articulation of Cover and Lopez has, we think, left the law uncertain in various respects. Of particular moment to the case before us, the law appears to be unclear on whether a manufacturer may be liable for failure to warn of dangers associated with foreseeable and/or known misuses of a product, where the product has been substantially modified by a third party’s removal of the product’s safety devices (i.e., in situations in which no liability for design defect would exist).5

The Court of Appeals has not addressed the circumstances under which a manufacturer may be liable for not warning against known or reasonably foreseeable misuse resulting in a dangerous product alteration. While Robinson squarely holds that a manufacturer may not be liable — in strict products liability or negligence — on a design defect claim for injuries caused in part by alteration or modification of a safety device, the question remains whether a manufacturer who knew of or should have foreseen the removal or modification is liable under either negligence or strict products liability for failure to warn of the dangers of misusing the product following such modification.6

The dissent in Robinson implied that the substantial modification defense created by the majority barred not only a manufacturer’s liability for defective design, but also, sub silentio, its liability for negligent failure to warn. The dissent stated that “[t]he majority opinion appears to proceed on the assumption that the plaintiffs suit was based essentially on a strict products liability theory alone.” Robinson, 49 N.Y.2d at 481, 403 N.E.2d at 444, 426 N.Y.S.2d at 722 (Fuchs-berg, /., dissenting). But, since the plaintiff, in his complaint, had also raised the issue of negligent failure to warn, and, under normal standards of negligence, the risk of injury due to lack of warning was foreseeable (because the manufacturer knew that the safety gates were being altered by the employer), *129the dissent asserted that the failure to permit recovery must implicitly have meant that the defendant was. under no duty to warn. See id. at 484-87, 426 N.Y.S.2d 717, 403 N.E.2d 440, 403 N.E.2d at 446-48, 426 N.Y.S.2d at 724-26 (Fuchsberg, dissenting).

Some lower federal court and New York appellate division cases have adopted this reading of Robinson. See, e.g., Kromer v. Beazer East, Inc., 826 F.Supp. 78, 81 (W.D.N.Y.1993) (finding that “[t]he disabling of the safety interlock switch by tying it up with a rag or a piece of string is, as a matter of law, a substantial alteration of the [product]” that precludes plaintiffs design defect and failure to warn claims); Ernest v. S.M.S. Eng’g Inc., 223 A.D.2d 801, 803, 635 N.Y.S.2d 799, 801 (3d Dep’t 1996) (holding that, because machine was substantially modified after it was delivered, plaintiffs claims were foreclosed under theories of design defect and inadequate warnings); Frey v. Rockford Safety Equip. Co., 154 A.D.2d 899, 899, 546 N.Y.S.2d 54, 55 (4th Dep’t 1989) (affirming a grant of summary judgment in a case in which the plaintiffs injury followed her employer’s installation of a switch allowing a punch press to be operated without its safety device, “whether [the] plaintiff seeks to hold defendants liable for an alleged product defect or for an alleged failure to warn”).7

Other New York appellate division cases, however, hold that the subsequent modification defense does not preclude liability where a plaintiff establishes that the manufacturer failed to warn of the dangers of using the machinery without the safety guard in place.8 Thus, in Darsan v. Guncalito Corp., 153 A.D.2d 868, 545 N.Y.S.2d 594 (2d Dep’t 1989), a meat wrapper employee suffered the amputation of his right hand, wrist, and forearm while he'was operating a meat grinder. At the time of the machine’s purchase, it was equipped with a safety guard over the feed pan; subsequently, the safety guard was removed by another employee. See id. at 869, 545 N.Y.S.2d at 595. The court ruled that the substantial modification defense of Robinson applied to the plaintiffs design defect claim, but:

[t]o the extent the plaintiffs’ action against the manufacturer -is based on the .theory that the machine was defective by virtue of the failure to display with sufficient prominence warnings of the danger of using the grinder without the safety guard in place, however, the complaint must be sustained. A manufacturer has a duty to warn of dangers associated with the reasonably foreseeable misuse of its product.

Id. at 870, 545 N.Y.S.2d at 596 (citations omitted).9

*130And in Miller v. Anetsberger Bros., 124 A.D.2d 1057, 508 N.Y.S.2d 954 (4th Dep’t 1986), the court likewise distinguished a failure to warn claim from a design defect claim in the context of the substantial modification defense. In Miller, the plaintiffs finger was injured when it was pulled between a set of rollers of a pizza dough roller machine that had three panels that were removable to permit access to the rollers during cleaning. See id. at 1058, 508 N.Y.S.2d at 955. The court reviewed a trial verdict in which:

[t]he court [had] instructed the jury on two theories of strict products liability; defective design and failure to warn. Concerning the disabling of the safety switch, the court charged that if the jury found that employees had intentionally disabled the safety switch, it would have to find that the machine was not defective in design; but that in deciding whether the manufacturer was liable for failure to warn, it could take into consideration, among other things, the testimony as to the convenience afforded by cleaning the machine while it was operating, knowledge the manufacturer may have had that users of the machine had cleaned it while it was operating, and the “ease of disability of that (safety) switch.”

Id.

So instructed, the jury found that the product was not defectively designed. But it nonetheless concluded that the manufacturer had failed to warn users of,the dangers involved in cleaning the machined while it was operating. See id. In upholding the jury verdict, the Second Department stated:

unlike ... Robinson, the issue involved is not whether the product was defectively designed, but whether the manufacturer had a duty to warn. Although a manufacturer is under no duty to design a product so that its safety devices may not be disabled, it may, under certain circumstances, be liable for a failure to warn of the consequences of using the machine when the safety devices are inoperative.

Id. at 1059, 508 N.Y.S.2d at 956 (citation omitted).

The Miller court then said:

Under the circumstances of this case, including the ease of avoiding the safety interlock, the knowledge that the manufacturer had that users were cleaning the rollers with the machine operating, and the convenience of doing so, the jury was entitled to find that defendant had a duty to warn plaintiff, a user of the machine, of dangers inherent in its use or foreseeable misuse of which it knew or should have known and were not obvious or known to plaintiff.

Id. (citations omitted).

Finally, in Smith v. Royce W. Day Co., 661 N.Y.S.2d 101 (3d Dep’t 1997), the plaintiff was injured while operating a forklift that was designed to be used either as a conventional forklift truck or as an order picker truck for elevated work. When used as an order picker truck, the operator controlled the truck from a platform (outside of the cab), which was latched to the truck. The plaintiff was using the truck in this manner, but with a different platform than that designed by the manufacturer of the forklift, and one that lacked the safety features of the manufacturer’s platform. This platform somehow fell off-the truck, causing serious injuries to the plaintiff. See id. at 102. The plaintiff sued the manufacturer and seller of the forklift, alleging defective design and failure to warn.10

The Appellate Division affirmed the trial court’s denial of summary judgment, and in doing so expressly addressed the failure to warn claim. It held: “Inasmuch as there were no explicit warnings on the forklift that it was not to be used without the [original manufacturer’s] platform ... we agree with the Supreme Court that the adequacy of the warnings is a question of fact for the jury.” Id. at 103 (citation omitted).11

*131Cases such as these — which, when a product has been substantially modified by a third party, distinguish between a failure to warn claim and a product design defect allegation — also squarely hold that it is up to the jury to decide whether the manufacturer, in fact, has a duty to warn. See Miller, 124 A.D.2d at 1059, 508 N.Y.S.2d at 956 (“[T]he jury was entitled to find that defendant had a duty to warn the plaintiff .... ”); see also Smith, 661 N.Y.S.2d at 102 (“the adequacy of the warnings is a question of fact for the jury”).

Given these cases, at least four possible views of New York law present themselves: Whenever a substantial modification has occurred, Robinson: (1) bars claims both for design defect and failure to warn, regardless of whether negligence and/or strict products liability is alleged; (2) bars all actions for design defect, whether based on strict liability or negligence, but does not foreclose suits for failure to warn, whether based on strict liability or negligence; (8) bars all actions for design defect, and also bars strict liability actions for failure to warn, but does not preclude claims based on negligent failure to warn; (4) bars only strict liability claims (whether for design defect or failure to warn) and forecloses neither category of suit when negligence is alleged and proved.

There is a logic to each of these possibilities under Robinson, and all but the last find support in New York cases subsequent to Robinson. The last, which distinguishes between liability for negligence and strict products liability, seems negated by Robinson, and yet is perhaps the most consistent of all with Robinson’s peroration which stated that its holding was crucial since any other decision “would be tantamount to imposing absolute liability on manufacturers for all product-related injuries.” Robinson, 49 N.Y.2d at 481, 403 N.E.2d at 444, 426 N.Y.S.2d at 721.12

*132We welcome enlightenment on which of these, or other possibilities,13 is the law of New York today.

III. CERTIFICATION

Certification is particularly appropriate when the state’s highest court has cast doubt on the scope or continued validity of one of its earlier holdings, or when there is some law in the intermediate state courts, but no definitive holding by the state’s highest tribunal. See McCarthy v. Olin Corp., 119 F.3d 148, 157, 158 n. 1 (2d Cir.1997) (Calabresi, J., dissenting) (citing Arthur L. Corbin, The Common Law of the United States, 47 Yale L.J. 1351, 1352 (1938); Harry Shulman, The Demise of Swift v. Tyson, 47 Yale L.J. 1336, 1350 (1938)).14 Absent certification, the danger in both situations — as Professors Corbin and Shulman foresaw — is that a party favored by the lower court decisions or by the weakened high court holding will seek federal jurisdiction with the knowledge that the federal courts, unlike the state’s highest court, will feel virtually bound to follow these decisions. As Professor Cor-bin put it, federal judges will be “limited in a way in which the [state] judges are not themselves limited.” Arthur L. Corbin, The Common Law of the United States, 47 Yale L.J. 1351, 1352 (1938); see also Harry Shulman, The Demise of Swift v. Tyson, 47 Yale L.J. 1336, 1350 (1938).

In fact, the case before us presents even stronger arguments for certification. For there are at least two divergent views of the law to be found in the intermediate New York courts on whether a negligent failure to warn claim can survive where liability based upon a design defect claim is precluded. And the New York Court of Appeals has not spoken definitively on the matter.

Accordingly, we certify the following question to the New York Court of Appeals:

Can manufacturer liability exist under a failure to warn theory in cases in which the substantial modification defense would preclude liability under a design defect theory, and if so, is such manufacturer liability barred as a matter of law on the facts of this case, viewed in the light most favorable to the plaintiff?

It is hereby ordered that the Clerk of this Court transmit to the Clerk of the Court of Appeals of the State of New York a Certificate, as set forth below, together" with a complete set of the briefs, appendix, and record filed in this Court by the parties. The parties are directed to bear equally such fees and costs as may be directed by the New York Court of Appeals.

This panel retains jurisdiction so that after we receive a response from the New York Court of Appeals we may dispose of various *133additional questions that may remain on appeal.

Certificate

The foregoing is hereby certified to the Court of Appeals of the State of New York, pursuant to § 500.17 of the Rules of the New York Court of Appeals (McKinney’s 1997 Rules of Court) and §' 0.27 of the Local Rules of the United States Court of Appeals for the Second Circuit, as ordered by the United States Court of Appeals for the Second Circuit.

OPINION OF THE COURT

ClPARICK, J.

In Robinson v Reed-Prentice Div. of Package Mach. Co. (49 *236NY2d 471, 475), we held that a manufacturer is not responsible for injuries resulting from substantial alterations or modifications of a product by a third party that render the product defective or otherwise unsafe. The present case certifies the issue of whether a plaintiff, whose design claim is barred by the substantial modification defense stated in Robinson, may nevertheless maintain a claim for failure to warn of the consequences of such modification. Finding the issue to be an open one, the United States Court of Appeals for the Second Circuit certified the following question to our Court:

“Can manufacturer liability exist under a failure to warn theory in cases in which the substantial modification defense would preclude liability under a design defect theory, and if so, is such manufacturer liability barred as a matter of law on the facts of this case, viewed in the light most favorable to the plaintiff?”

We answer the first part of the certified question in the affirmative and decline to answer the second part of the question in deference to the Second Circuit’s review and application of existing principles of law to the facts, as amplified by the full record before that Court.

I

The facts as presented by the Circuit Court are as follows:

“Luis Liriano, a seventeen-year-old employee in the meat department at Super Associated grocery store (‘Super’), was injured on the job in September 1993 when he was feeding meat into a commercial meat grinder whose safety guard had been removed. His hand was caught in the ‘worm’ that grinds the meat; as a result, his right hand and lower forearm were amputated.

“The meat grinder was manufactured and sold in 1961 by Hobart Corporation (‘Hobart’). At the time of the sale, it had an affixed safety guard that prevented the user’s hands from coming into contact with the feeding tube and the grinding ‘worm.’ No warnings were placed on the machine or otherwise given to indicate that it was dangerous to operate the machine without the safety guard in place. Subsequently, Hobart became aware that a significant number of purchasers of its meat grinders had removed the safety guards. And in 1962, Hobart began issuing warnings on its meat grinders concerning removal of the safety guard.

*237“There is no dispute that, when Super acquired the grinder, the safety guard was intact. It is also not contested that, at the time of Liriano’s accident, the safety guard had been removed. There is likewise no doubt that Hobart actually knew, before the accident, that removals of this sort were occurring and that use of the machine without the safety guard was highly dangerous. And Super does not question that the removal of the guard took place while the guard was in its possession.

“Liriano sued Hobart under theories of negligence and strict products liability for, inter alia, defective product design and failure to warn. He brought his claims in the Supreme Court, Bronx County, New York. Hobart removed the case to the United States District Court for the Southern District of New York, and also impleaded Super as a third-party defendant, seeking indemnification and/or contribution. The District Court (Shira A. Scheindlin, Judge) dismissed all of Liriano’s claims except those based on failure to warn. Following trial, the jury concluded that the manufacturer’s failure to warn was the proximate cause of Liriano’s injuries and apportioned liability 5% to Hobart and 95% to Super. On partial retrial, limited to the extent of Liriano’s responsibility, the jury assigned, him 331/s% of the responsibility. On appeal, Hobart and Super argue, inter alia, that the question of whether Hobart had a duty to warn Liriano should have been decided in their favor by the court, as a matter of law. It is this question that gives rise to the current certification.”

II

A manufacturer who places a defective product on the market that causes injury may be liable for the ensuing injuries (see, Codling v Paglia, 32 NY2d 330, 342). A product may be defective when it contains a manufacturing flaw, is defectively designed or is not accompanied by adequate warnings for the use of the product (see, Codling v Paglia, 32 NY2d 330, supra; Micallef v Miehle Co., 39 NY2d 376; Torrogrossa v Towmotor Co., 44 NY2d 709; see also, Robinson v Reed-Prentice Div. of Package Mach. Co., 49 NY2d 471, 478, supra). A manufacturer has a duty to warn against latent dangers resulting from foreseeable uses of its product of which it knew or should have known (Rastelli v Goodyear Tire & Rubber Co., 79 NY2d 289, 297). A manufacturer also has a duty to warn of the danger of unintended uses of a product provided these uses are reasonably foreseeable (see, Lugo v LJN Toys, 75 NY2d 850; McLaughlin v Mine Safety Appliances Co., 11 NY2d 62; 1 Weinberger, New York Products Liability, § 17:07, at 17-10 [2d ed]).

*238A manufacturer is not liable for injuries caused by substantial alterations to the product by a third party that render the product defective or unsafe (Robinson v Reed-Prentice Div. of Package Mach. Co., 49 NY2d 471, supra). Where, however, a product is purposefully manufactured to permit its use without a safety feature, a plaintiff may recover for injuries suffered as a result of removing the safety feature (Lopez v Precision Papers, 67 NY2d 871, 873).

Several intermediate appellate courts have interpreted Robinson to mean that, where a substantial alteration of a product occurs, an injured party is also precluded from asserting a claim for failure to warn (see, e.g., Bonilla v Schjeldahl, Inc., 242 AD2d 651; Ernest v S.M.S. Eng’g, 223 AD2d 801, 803; Frey v Rockford Safety Equip. Co., 154 AD2d 899). Relying on Robinson and these lower court decisions, Hobart urges that the plaintiff’s failure-to-warn claim should be barred as a matter of law. Robinson, however, did not resolve the issue of whether preclusion of a claim for defective design because of substantial alteration by a third party should also bar a claim for failure to warn.

This Court’s rationale in Robinson stemmed from the recognition that a manufacturer is responsible for a “purposeful design choice” that presents an unreasonable danger to the user (see, Robinson v Reed-Prentice Div. of Package Mach. Co., supra, 49 NY2d, at 480). This responsibility derives from the manufacturer’s superior position to anticipate reasonable uses of its product and its obligation to design a product that is not harmful when used in that manner. However, this duty is not open-ended, and it is measured as of the time the product leaves the manufacturer’s premises. Thus, a manufacturer is not required to insure that subsequent owners and users will not adapt the product to their own unique uses. That kind of obligation is much too broad and would effectively impose liability on manufacturers for all product-related injuries (id., at 480-481).

While this Court stated that principles of foreseeability are inapplicable where there has been a substantial modification of the product, that discussion was limited to the manufacturer’s responsibility for defective design where there had been a substantial alteration of a product by a third party (id., at 479, 480). Thus, this Court stated that a manufacturer’s duty “does not extend to designing a product that is impossible to abuse or one whose safety features may not be circumvented” and the manufacturer need not trace its “product through every link in *239the chain of distribution to insure that users will not adapt the product to suit their own unique purposes” (id., at 480-481 [emphasis added]).1

Hobart and amici argue that the rationale of Robinson is equally applicable to failure-to-warn claims where a substantial modification of the product occurs and that application of the failure-to-warn doctrine in these circumstances would undermine Robinson’s policy justification and destroy its purpose. This Court is not persuaded that the existence of a substantial modification defense precludes, in all cases, a failure to warn claim.

The factors militating against imposing a duty to design against foreseeable post-sale product modifications are either not present or less cogent with respect to a duty to warn against making such modifications. The existence of a design defect involves a risk/utility analysis that requires an assessment of whether "if the design defect were known at the time of the manufacture, a reasonable person would conclude that the utility of the product did not outweigh the risk inherent in marketing a product designed in that manner” (Voss v Black & Decker Mfg. Co., 59 NY2d 102, 108; see also, Denny v Ford Motor Co., 87 NY2d 248, 257). Such an analysis would be unreasonably complicated, and may very well be impossible to measure, if a manufacturer has to factor into the design equation all foreseeable post-sale modifications. Imposition of a duty that is incapable of assessment would effectively result in the imposition of absolute liability on manufacturers for all product-related injuries (see, Robinson v Reed-Prentice Div. of Package Mach. Co., supra, 49 NY2d, at 481). This Court has drawn a policy line against that eventuality.

These concerns are not as strongly implicated in the context of a duty to warn. Unlike design decisions that involve the consideration of many interdependent factors, the inquiry in a duty to warn case is much more limited, focusing principally on the foreseeability of the risk and the adequacy and effectiveness of any warning. The burden of placing a warning on a product is less costly than designing a perfectly safe, tamper-resistant product. Thus, although it is virtually impossible to design a product to forestall all future risk-enhancing modifica*240tions that could occur after the sale, it is neither infeasible nor onerous, in some cases, to warn of the dangers of foreseeable modifications that pose the risk of injury.

Furthermore, this Court has held that a manufacturer may be liable for failing to warn against the dangers of foreseeable misuse of its product (see, Lugo v LJN Toys, 75 NY2d 850, supra; Kriz v Schum, 75 NY2d 25; 1 Weinberger, op. cit., § 17:07). No material distinction between foreseeable misuse and foreseeable alteration of a product is evident in this context. Thus, the rationale of Lugo v LJN Toys should apply to both situations.2

This Court has also recognized that, in certain circumstances, a manufacturer may have a duty to warn of dangers associated with the use of its product even after it has been sold. Such a duty will generally arise where a defect or danger is revealed by user operation and brought to the attention of the manufacturer; the existence and scope of such a duty are generally fact-specific (see, Cover v Cohen, 61 NY2d 261, 274-277 [technical service bulletin issued by manufacturer and sent to vendor 13 months after delivery relevant and admissible]; see also, Kriz v Schum, 75 NY2d 25, supra [upholding plaintiffs claim based on a post-sale failure to warn]; Haran v Union Carbide Corp., 68 NY2d 710, 712 [no notice to manufacturer of a danger or defect in the product]).3

The justification for the post-sale duty to warn arises from a manufacturer’s unique (and superior) position to follow the use and adaptation of its product by consumers (see, Cover v Cohen, 61 NY2d 261, supra). Compared to purchasers and users of a product, a manufacturer is best placed to learn about post-sale defects or dangers discovered in use. A manufacturer’s *241superior position to garner information and its corresponding duty to warn is no less with respect to the ability to learn of modifications made to or misuse of a product. Indeed, as in this case, Hobart was the only party likely to learn about the removal of the safety guards and, as it ultimately did, pass along warnings to customers.

This Court therefore concludes that manufacturer liability can exist under a failure-to-warn theory in cases in which the substantial modification defense as articulated in Robinson might otherwise preclude a design defect claim.

We should emphasize, however, that a safety device built into the integrated final product is often the most effective way to communicate that operation of the product without the device is hazardous. Thus, where the injured party was fully aware of the hazard through general knowledge, observation or common sense, or participated in the removal of the safety device whose purpose is obvious, lack of a warning about that danger may well obviate the failure to warn as a legal cause of an injury resulting from that danger (see, e.g., Smith v Stark, 67 NY2d 693, 694; Bigness v Powell Elecs., 209 AD2d 984, 985; Baptiste v Northfield Foundry & Mach. Co., 184 AD2d 841, 843; Lombard v Centrico, Inc., 161 AD2d 1071, 1073). Thus, in appropriate cases, courts could as a matter of law decide that a manufacturer’s warning would have been superfluous given an injured party’s actual knowledge of the specific hazard that caused the injury (see, e.g., Smith v Stark, supra; Baptiste v Northfield Foundry & Mach. Co., supra). Nevertheless, in cases where reasonable minds might disagree as to the extent of plaintiffs knowledge of the hazard, the question is one for the jury (see, e.g., Jiminez v Dreis & Krump Mfg. Co., 736 F2d 51, 55-56 [2d Cir 1984]).

Similarly, a limited class of hazards need not be warned of as a matter of law because they are patently dangerous or pose open and obvious risks (see, Schiller v National Presto Indus., 225 AD2d 1053; Bazerman v Gardall Safe Corp., 203 AD2d 56; cf., Amatulli v Delhi Constr. Corp., 77 NY2d 525, 532-533 [had aboveground pool not been installed two feet below ground level, “its depth would have been readily apparent and would itself have served as an evident warning against diving”]; see also, 1 Weinberger, op. cit., § 17:07, at 17-8 [no duty to warn where danger “can be patently recognized simply as a matter of common sense”]; Prosser and Keeton, Torts § 96, at 686-687 [5th ed] [courts treat obvious danger as “a condition that would ordinarily be seen and the danger of which would ordinarily be *242appreciated by those who would be expected to use the product”]). Where a danger is readily apparent as a matter of common sense, “there should be no liability for failing to warn someone of a risk or hazard which he [or she] appreciated to the same extent as a warning would have provided” (Prosser and Keeton, op. cit., at 686). Put differently, when a warning would have added nothing to the user’s appreciation of the danger, no duty to warn exists as no benefit would be gained by requiring a warning. On the other hand, the open and obvious defense generally should not apply when there are aspects of the hazard which are concealed or not reasonably apparent to the user.

This is particularly important because requiring a manufacturer to warn against obvious dangers could greatly increase the number of warnings accompanying certain products. If a manufacturer must warn against even obvious dangers, “[t]he list of foolish practices warned against would be so long, it would fill a volume” (Kerr v Koemm, 557 F Supp 283, 288 [SDNY 1983]). Requiring too many warnings trivializes and undermines the entire purpose of the rule, drowning out cautions against latent dangers of which a user might not otherwise be aware. Such a requirement would neutralize the effectiveness of warnings as an inexpensive way to allow consumers to adjust their behavior based on knowledge of a product’s inherent dangers.

While important to warning law, the open and obvious danger exception is difficult to administer (see, e.g., Jacobs, Toward a Process-Based Approach to Failure-to-Warn Law, 71 NC L Rev 121, 128-137 [1992]). The fact-specific nature of the inquiry into whether a particular risk is obvious renders bright-line pronouncements difficult, and in close cases it is easy to disagree about whether a particular risk is obvious. It is hard to set a standard for obviousness that is neither under- nor over-inclusive. Because of the factual nature of the inquiry, whether a danger is open and obvious is most often a jury question (see, e.g., Bolm v Triumph Corp., 33 NY2d 151, 159-160). Where only one conclusion can be drawn from the established facts, however, the issue of whether the risk was open and obvious may be decided by the court as a matter of law.

m

Having now answered the first part of the question certified to us by the Second Circuit — manufacturer liability can exist *243under a failure-to-warn theory in cases in which the substantial modification defense would preclude liability under a design defect theory — we turn to the second: “if so, is such manufacturer liability barred as a matter of law on the facts of this case, viewed in the light most favorable to the plaintiff?”

Failure-to-warn liability is intensely fact-specific, including but not limited to such issues as feasibility and difficulty of issuing warnings in the circumstances (see, n 3, supra)', obviousness of the risk from actual use of the product; knowledge of the particular product user; and proximate cause. The Second Circuit’s opinion does not indicate that there is an unsettled or open question of New York substantive law in any of these respects, and indeed explicitly reserves jurisdiction so that the Second Circuit itself can dispose of various additional questions that may remain on appeal. This Court therefore concludes that any remaining question posed is appropriately addressed by the Second Circuit in light of the substantive law question we have now resolved.

Accordingly, the certified question should be answered as follows: manufacturer liability for failure to warn may exist in cases where the substantial modification defense would preclude liability on a design defect theory.

Chief Judge Kaye and Judges Titone, Bellacosa, Smith, Levine and Wesley concur.

Following certification of a question by the United States Court of Appeals for the Second Circuit and acceptance of the question by this Court pursuant to section 500.17 of the Rules of the Court of Appeals (22 NYCRR 500.17), and after hearing argument by counsel for the parties and consideration of the briefs and the record submitted, certified question answered as follows: Manufacturer liability may exist under a failure-to-warn theory in cases in which the substantial modification defense would preclude liability under a design defect theory.

Judge JON 0. NEWMAN concurs in a separate opinion.

CALABRESI, Circuit Judge:

In Liriano v. Hobart Corp., 132 F.3d 124 (2d Cir.1998) (“Liriano /”), we certified to the New York Court of Appeals the question of whether a manufacturer can be liable under a failure-to-warn theory in a case in which the substantial modification defense would preclude liability under a design defect theory. See id. at 132. We also certified the question of whether, if failure-to-warn liability could exist, it would nonetheless be unavailable as a matter of law on the facts of the present case. See id. The New York Court of Appeals answered the first question in the affirmative and declined to answer the second. See Liriano v. Hobart Corp., 92 N.Y.2d 232, 236, 700 N.E.2d 303, 304, 677 N.Y.S.2d 764, 765 (1998) (“Liriano II”). Consequently, we now address the second question ourselves, and we find it to be a close one. Viewing the facts, as we must, in the light most favorable to the plaintiff, we resolve that question in the negative. We also find that all other claims the appellants have raised on appeal lack merit. We therefore affirm the decision of the district court granting judgment and damages for the plaintiff.

BACKGROUND

The facts of this case are set out in Liriano I and again in Liriano II. See Liriano I, 132 F.3d at 125-26; Liriano II, 92 N.Y.2d at 236-37, 700 N.E.2d at 305, 677 N.Y.S.2d at 766. We repeat only those that are necessary to resolve the issues that remain before us.

Luis Liriano was severely injured on the job in 1993 when his hand was caught in a meat grinder manufactured by Hobart Corporation (“Hobart”) and owned by his employer, Super Associated (“Super”). The meat grinder had been sold to Super with a safety guard, but the safety guard was removed while the machine was in Super’s possession and was not affixed to the meat grinder at the time of the accident. The machine bore no warning indicating that the grinder should be operated only with a safety guard attached.

Liriano sued Hobart under several theories, including failure to warn. Hobart brought a third-party claim against Super. The United States District Court for the Southern District of New York (Shira A. Scheindlin, J.) dismissed all of Liriano’s claims except the one based on failure to warn, and the jury returned a verdict for Liriano on that claim. It attributed five percent of the liability to Hobart and ninety-five percent to Super. The district court then held a partial retrial limited to the issue of whether and to what extent Liriano was responsible for his own injury. On that retrial, the jury assigned Liriano one-third of the fault.

Before she entered judgment based on these calculations, Judge Scheindlin granted Liriano’s motion to add $21,252.34 to the total damage award. The increase reflected the amount of a hospital bill that had been submitted to the jury during trial but somehow had not been included in the initial damage calculation.

Hobart and Super appealed, arguing (1) that as a matter of law, there was no duty to warn, and (2) that even if there had been a duty to warn, the evidence presented was not sufficient to allow the failure-to-warn claim to reach the jury. Super further argued (3) that the district court erred in holding a retrial on the issue of Liriano’s comparative fault without also retrying Hobart’s and Super’s shares of fault relative to each other, *267and (4) that the district court s addition of the hospital bill to its damage calculation was an impermissible additur. We certified questions (1) and (2) to the New York Court of Appeals. See Liriano I, 132 F.3d at 132. That Court answered question (1) in Liri-ano’s favor, saying that there can indeed be a duty to warn in a case like this one. See Liriano II, 92 N.Y.2d at 243, 700 N.E.2d at 309, 677 N.Y.S.2d at 770. The Court of Appeals, however, declined to answer question (2). See id.

We now resolve questions (2), (3), and (4).

DISCUSSION

A. Sufficiency of the Evidence

Hobart makes two arguments challenging the sufficiency of the evidence. The first concerns the obviousness of the danger that Liriano faced, and the second impugns the causal relationship between Hobart’s negligence and Liriano’s injury. Each of these arguments implicates issues long debated in the law of torts. With respect to the asserted clarity of the danger, the question is when a danger is so obvious that a court can determine, as a matter of law, that no additional warning is required. With respect to causation, the issue is whether a jury may infer that a defendant’s particular negligence was the cause-in-fact of a plaintiffs actual injury from the general fact that negligence like the defendant’s tends to cause injuries like the plaintiffs. The obviousness question was the subject of an important but now generally rejected opinion by Justice Holmes, then on the Massachusetts Supreme Judicial Court;1 the causation question is answered in a celebrated opinion of Judge Cardozo, then on the New York Court of Appeals.2 We examine each in turn.

(1) Obviousness

More than a hundred years ago, a Boston woman named Maria Wirth profited from an argument about obviousness as a matter of law that is very similar to the one Hobart urges today. See Lorenzo v. Wirth, 170 Mass. 596, 49 N.E. 1010 (1898). Wirth was the owner of a house on whose property there was a coal hole. See id. at 599, 49 N.E. at 1010. The hole abutted the street in front of the house, and casual observers would have no way of knowing that the area around the hole was not part of the public thoroughfare. See id. at 599, 49 N.E. at 1011. A pedestrian called Lorenzo fell into the coal hole and sued for her injuries. See id. Writing for a majority of the Supreme Judicial Court of Massachusetts, Oliver Wendell Holmes, Jr., held for the defendant. He noted that, at the time of the accident, there had been a heap of coal on the street next to the coal hole, and he argued that such a pile provided sufficient warning to passers-by that they were in the presence of an open hole. “A heap of coal on a sidewalk in Boston is an indication, according to common experience, that there very possibly may be a coal hole to receive it.” Id. at 601, 49 N.E. at 1011. And that was that.

It was true, Holmes acknowledged, that “blind men, and foreigners unused to our ways, have a right to walk in the streets,” id. at 600, 49 N.E. at 1011, and that such people might not benefit from the warning that piles of coal provided to sighted Bostonians. But Holmes wrote that coal-hole eases were simple, common, and likely to be oft repeated, and he believed it would be better to establish a clear rule than to invite fact-specific inquiries in every such case. “In simple cases of this sort,” he explained, “courts have felt able to determine what, in every case, however complex, defendants are bound at their peril to know.” Id. With the facts so limited, this was an uncomplicated case in which the defendant could, as a matter of law, rely on the plaintiffs responsibility to know what danger she faced.

Justice Knowlton disagreed. See id. at 601-04, 49 N.E. at 1011-13 (Knowlton, J., dissenting). His opinion delved farther into the particular circumstances than did Holmes’s opinion for the majority. In so doing, he showed that Lorenzo’s failure to appreciate her peril might have been foreseen by Wirth and hence that Wirth’s failure *268to warn might constitute negligence. He noted, for example, that the accident occurred after nightfall, when Lorenzo perhaps could not see, or recognize, the heap of coal for what it was. See id. at 603, 49 N.E. at 1012. There was “a throng of persons” on the street, such that it would have been difficult even in daylight to see very far ahead of where one was walking. See id. at 603-04, 49 N.E. at 1012. And the plaintiff was, in fact, a foreigner unused to Boston’s ways. “[S]he had just come from Spain, and had never seen coal put into a cellar through a coal hole.” Id. at 603, 49 N.E. at 1012. In sum, the case was not the “simple” one that Holmes had made it out to be. What is more, none of the facts he recited was either unusual or unforeseeable by Wirth. “What kind of conduct is required under complex conditions, to reach the usual standard of due care, namely, the ordinary care of persons of common prudence, is a question of fact .... [and thus] a question for a jury.” Id. at 604, 49 N.E. at 1012-13 (emphasis added). Even cases involving “obvious” dangers like coal holes, Knowlton believed, might not be resolvable as matters of law when viewed in the fidlness of circumstances that rendered the issue less clear than it would be when posed in the abstract.

Holmes commanded the majority of the Supreme Judicial Court in 1898, but Knowl-ton’s position has prevailed in the court of legal history. “ ‘[T]he so-called Holmes view — that standards of conduct ought increasingly to be fixed by the court for the sake of certainty — has been largely rejected.... The tendency has been away from fixed standards and towards enlarging the sphere of the jury.’ ” Fowler V. Harper, Fleming James, Jr., & Oscar S. Gray, The Law of Torts § 15.3, at 358-59 n. 16 (2d ed.1986) (hereinafter Harper & James) (quoting Nuckoles v. F.W. Woolworth Co., 372 F.2d 286, 289 (4th Cir.1967)).

The courts of New York have several times endorsed Knowlton’s approach and ruled that judges should be very wary of taking the issue of liability away from juries, even in situations where the relevant dangers might seem obvious, and especially when the cases in question turn on particularized facts. See, e.g., Havas v. Victory Paper Stock Co., 49 N.Y.2d 381, 388, 402 N.E.2d 1136, 1139-40, 426 N.Y.S.2d 233, 237 (1980) (stating that negligence is an issue “particularly appropriate to leave ... to the jury” because of the “idiosyncratic nature of most tort cases” and because “reasonableness” is generally appropriate for jury resolution); Cabri v. Long Island R.R. Co., 306 N.Y. 765, 118 N.E.2d 475 (1954) (holding that the danger of crossing railroad tracks is not so obvious as to prevent the issue of contributory negligence from reaching the jury).3 See also Stagl v. Delta Airlines, Inc., 52 F.3d 463, 470-71 (2d Cir.1995) (noting the demise of the Holmes position and collecting cases); Fleming James, Jr., Geoffrey C. Hazard, Jr., & John Leubsdorf, Civil Procedure § 7.21, at 371 (4th ed.1992) (stating that the decline of the Holmes view has been especially pronounced in tort suits for personal injury); Harper & James, § 17.2, at 571-72 nn. 8-13, 573-74 nn. 22-26, 576-78 nn. 33-37 (collecting many authorities).

But the secular decline of the Holmes position and the concomitant tendency of the New York Court of Appeals to permit issues of obviousness to go to the jury do not fully dispose of the question before us. After all, as Holmes himself might have cautioned, general trends are far from conclusive in concrete cases. Cf. Lochner v. New York, 198 U.S. 45, 75, 25 S.Ct. 539, 49 L.Ed. 937 (1905) (Holmes, J., dissenting). And it is not surprising that there have been situations in which New York state courts have deemed dangers to be sufficiently clear so that warnings were, as a matter of law, not necessary. See, e.g., Dickerson v. George J. Meyer Mfg., 248 A.D.2d 970, 971, 669 N.Y.S.2d 1001, 1002 (4th Dep’t 1998) (holding that there is no duty to warn of the danger of closely examining the mechanical workings of a machine while the machine is operating); Pigliavento v. Tyler Equip. Corp., 248 A.D.2d 840, 842, 669 N.Y.S.2d 747, 749 (3d Dep’t 1998) (holding that there is no duty to warn of the *269danger of falling from an unguarded platform on a concrete mixer truck); Caris v. Mele, 134 A.D.2d 475, 476, 521 N.Y.S.2d 260, 261 (2d Dep’t 1987) (holding that there is no duty to warn of the danger of diving headfirst into an above-ground swimming pool only four feet deep).

If the question before us were, therefore, simply whether meat grinders are sufficiently known to be dangerous so that manufacturers would be justified in believing that further warnings were not needed, we might be in doubt. On one hand, just as a coal hole was deemed a danger appreciated by most Bostonians in 1898, so most New Yorkers would probably appreciate the danger of meat grinders a century later. Any additional warning might seem superfluous. On the other hand, Liriano was only seventeen years old at the time of his injury and had only recently immigrated to the United States. He had been on the job at Super for only one week. He had never been given instructions about how to use the meat grinder, and he had used the meat grinder only two or three times. And, as Judge Seheindlin noted, the mechanism that injured Liriano would not have been visible to someone who was operating the grinder. It could be argued that such a combination of facts was not so unlikely that a court should say, as a matter of law, that the defendant could not have foreseen them or, if aware of them, need not have guarded against them by issuing a warning. That argument would draw strength from the Court of Appeals’ direction that the question of whether a warning was needed must be asked in terms of the information available to the injured party rather than the injured party’s employer, see Liriano II, 92 N.Y.2d at 241, 700 N.E.2d at 308, 677 N.Y.S.2d at 769, and its added comment that “in cases where reasonable minds might disagree as to the extent of the plaintiffs knowledge of the hazard, the question is one for the jury.” Id.

Nevertheless, it remains the fact that meat grinders are widely known to be dangerous. Given that the position of the New York courts on the specific question before us is anything but obvious, we might well be of two minds as to whether a failure to warn that meat grinders are dangerous would be enough to raise a jury issue.4

*270But to state the issue that way would be to misunderstand the complex functions of warnings. As two distinguished torts scholars have pointed out, a warning can do more than exhort its audience to be careful. It can also affect what activities the people warned choose to engage in. See James A. Henderson, Jr., and Aaron D. Twerski, Doctrinal Collapse in Products Liability: The Empty Shell of Failure to Warn, 65 N.Y.U. L.Rev. 265, 285 (1990). And where the function of a warning is to assist the reader in making choices, the value of the warning can lie as much in making known the existence of alternatives as in communicating the fact that a particular choice is dangerous. It follows that the duty to warn is not necessarily obviated merely because a danger is clear.

To be more concrete, a warning can convey at least two types of messages. One states that a particular place, object, or activity is dangerous. Another explains that people need not risk the danger posed by such a place, object, or activity in order to achieve the purpose for which they might have taken that risk. Thus, a highway sign that says “Danger—Steep Grade” says less than a sign that says “Steep Grade Ahead—Follow Suggested Detour to Avoid Dangerous Areas.”

If the hills or mountains responsible for the steep grade are plainly visible, the first sign merely states what a reasonable person would know without having to be warned. The second sign tells drivers what they might not have otherwise known: that there is another road that is flatter and less hazardous. A driver who believes the road through the mountainous area to be the only way to reach her destination might well choose to drive on that road despite the steep grades, but a driver who knows herself to have an alternative might not, even though her understanding of the risks posed by the steep grade is exactly the same as those of the first driver. Accordingly, a certain level of obviousness as to the grade of a road might, in principle, eliminate the reason for posting a sign of the first variety. But no matter how patently steep the road, the second kind of sign might still have a beneficial effect. As a result, the duty to post a sign of the second variety may persist even when the danger of the road is obvious and a sign of the first type would not be warranted.

One who grinds meat, like one who drives on a steep road, can benefit not only from being told that his activity is dangerous but from being told of a safer way. As we have said, one can argue about whether the risk involved in grinding meat is sufficiently obvious that a responsible person would fail to warn of that risk, believing reasonably that it would convey no helpful information. But if it is also the case—as it is—that the risk posed by meat grinders can feasibly be reduced by attaching a safety guard, we have a different question. Given that attaching guards is feasible, does reasonable care require that meat workers be informed that they need not accept the risks of using un*271guarded grinders? Even if most ordinary users may—as a matter of law—know of the risk of using a guardless meat grinder, it does not follow that a sufficient number of them will—as a matter of law—also know that protective guards are available, that using them is a realistic possibility, and that they may ask that such guards be used. It is precisely these last pieces of information that a reasonable manufacturer may have a duty to convey even if the danger of using a grinder were itself deemed obvious.

Consequently, the instant case does not require us to decide the difficult question of whether New York would consider the risk posed by meat grinders to be obvious as a matter of law. A jury could reasonably find that there exist people who are employed as meat grinders and who do not know (a) that it is feasible to reduce the risk with safety guards, (b) that such guards are made available with the grinders, and (c) that the grinders should be used only with the guards. Moreover, a jury can also reasonably find that there are enough such people, and that warning them is sufficiently inexpensive, that a reasonable manufacturer would inform them that safety guards exist and that the grinder is meant to be used only with such guards. Thus, even if New York would consider the danger of meat grinders to be obvious as a matter of law, that obviousness does not substitute for the warning that a jury could, and indeed did, find that Hobart had a duty to provide. It follows that we cannot say, as a matter of law, that Hobart had no duty to warn Liriano in the present case. We therefore decline to adopt appellants’ argument that the issue of negligence was for the court only and that the jury was not entitled, on the evidence, to return a verdict for Liriano.

(2) Causation

On rebriefing following the Court of Appeals decision, Hobart has made another argument as to why the jury should not have been allowed to find for the plaintiff. In this argument, Hobart raises the issue of causation. It maintains that Liriano “failed to present any evidence that Hobart’s failure to place a warning [on the machine] was causally related to his injury.” Whether or not there had been a warning, Hobart says, Liri-ano might well have operated the machine as he did and suffered the injuries that he suffered. Liriano introduced no evidence, Hobart notes, suggesting either that he would have refused to grind meat had the machine borne a warning or that a warning would have persuaded Super not to direct its employees to use the grinder without the safety attachment.

Hobart’s argument about causation follows logically from the notion that its duty to warn in this case merely required Hobart to inform Liriano that a guard was available and that he should not use an unguarded grinder. The contention is tightly reasoned, but it rests on a false premise. It assumes that the burden was on Liriano to introduce additional evidence showing that the failure to warn was a but-for cause of his injury, even after he had shown that Hobart’s wrong greatly increased the likelihood of the harm that occurred. But Liriano does not bear that burden. When a defendant’s negligent act is deemed wrongful precisely because it has a strong propensity to cause the type of injury that ensued, that very causal tendency is evidence enough to establish a prima facie case of cause-in-fact. The burden then shifts to the defendant to come forward with evidence that its negligence was not such a but-for cause.

We know, as a general matter, that the kind of negligence that the jury attributed to the defendant tends to cause exactly the kind of injury that the plaintiff suffered. Indeed, that is what the jury must have found when it ruled that Hobart’s failure to warn constituted negligence. In such situations, rather than requiring the plaintiff to bring in more evidence to demonstrate that his case is of the ordinary kind, the law presumes normality and requires the defendant to adduce evidence that the case is an exception. Accordingly, in a case like this, it is up to the defendant to bring in evidence tending to rebut the strong inference, arising from the accident, that the defendant’s negligence was in fact a but-for cause of the plaintiffs injury. See Zuchowicz v. United States, 140 F.3d 381, 388 nn. 6-7, 390-91 (2d Cir.1998).

*272This shifting of the onus procedendi has long been established in New York. Its classic statement was made more than seventy years ago, when the Court of Appeals decided a case in which a car collided with a buggy driving after sundown without lights. See Martin v. Herzog, 228 N.Y. 164, 170, 126 N.E. 814, 816 (1920). The driver of the buggy argued that his negligence in driving without lights had not been shown to be the cause-in-fact of the accident. Writing for the Court, Judge Cardozo reasoned that the legislature deemed driving without lights after sundown to be negligent precisely because not using lights tended to cause accidents of the sort that had occurred in the case. See id. at 168, 126 N.E. at 815. The simple fact of an accident under those conditions, he said, was enough to support the inference of but-for causal connection between the negligence and the particular accident. See id. at 170, 126 N.E. at 816. The inference, he noted, could be rebutted. But it was up to the negligent party to produce the evidence supporting such a rebuttal. See id.

The words that Judge Cardozo applied to the buggy’s failure to use lights are equally applicable to Hobart’s failure to warn: “If nothing else is shown to break the connection, we have a case, prima facie sufficient, of negligence contributing to the result.” Id. Under that approach, the fact that Liriano did not introduce detailed evidence of but-for causal connection between Hobart’s failure to warn and his injury cannot bar his claim. His prima facie case arose from the strong causal linkage between Hobart’s negligence and the harm that occurred. See Guido Calabresi, Concerning Cause and the Law of Torts: An Essay for Harry Kalven, Jr., 43 U. Chi. L.Rev. 69 (1975) (describing the concept of “causal link”). And, since the prima facie case was not rebutted, it suffices.5

B. Partial Retrial

The district court ordered a retrial on the issue of Liriano’s comparative negligence but declined to do the same as to the proper allocation of fault between the two defendants. As a general matter, judges may order retrial on some but not all issues in a case, and they may do so even when the issues are related. Under Akermanis v. Sea-Land Service, Inc., 688 F.2d 898 (2d Cir.1982), a district judge has discretion to order retrial of the issue of a plaintiffs comparative negligence without requiring the fact-finder to reconsider the total extent of damages. See id. at 906-07. As we explained in Crane v. Consolidated Rail Corp., 731 F.2d 1042 (2d Cir.1984), Akermanis teaches that a judge need not infer jury error on a given issue merely because she finds jury error on a related issue. See id. at 1050-51.

It is possible that a judge might conclude that the facts of a given case required reexamining the relative liabilities of two defendants as part of a retrial on the issue of a plaintiffs comparative negligence. But on the facts of this case, and in light of Aker-manis and Crane, such a retrial is not mandated. The district court decided that the relative shares of fault attributed to Hobart and Super were “amply supported by the record.” We affirm that decision.

C. Damage Adjustment

Appellant Super argues that the district court granted an impermissible additur when it increased the damage award to account for a hospital bill whose amount and nature were not in dispute. Additur is a practice by which a judge offers a defendant the choice between facing a retrial and accepting a damage award higher than that determined by the jury. Like remittitur, it is a tool that judges use to fix damages—something that can generally be done only by the fact-finder—without actually having to hold a second trial.

Under the rule of Dimick v. Schiedt, 293 U.S. 474, 55 S.Ct. 296, 79 L.Ed. 603 (1935), federal courts are denied the same freedom to use additur that is enjoyed by many state court judges. In this case, however, there was no true additur. The district court did not divine a figure and then make *273the defendants choose between an increased damage award and a new trial. It simply adjusted the jury award to account for a discrete item that manifestly should have been part of the damage calculations and as to whose amount there was no dispute. When a jury has already found liability, federal courts may make such adjustments without running afoul of Dimick. See, e.g., United States Equal Employment Opportunity Comm’n v. Massey Yardley Chrysler Plymouth, Inc., 117 F.3d 1244, 1252-53 (11th Cir. 1997); Decato v. Travelers Ins. Co., 379 F.2d 796, 798 (1st Cir. 1967).

The district court did not err. We affirm its decision in all respects.

JON 0. NEWMAN, Circuit Judge,

concurring:

When this diversity appeal was first before us, we were sufficiently unsure about how the case should be decided under New York law that we asked the New York Court of Appeals to answer two questions. The first was whether a manufacturer that designs a product in a reasonably safe manner can nonetheless be held negligent for failure to warn about a product’s danger that results from a modification of the product after its sale. The New York Court of Appeals answered that such failure-to-warn liability can exist. In order to understand how New York would apply its tort law in this rather unusual context, we also asked the State’s highest court whether such failure-to-warn liability is a fact issue for a jury under the circumstances of this case. Unfortunately, the Court of Appeals declined to answer the second question.

The Court of Appeals’ decision not to answer our fact-specific inquiry is understandable, since the certification process is most usefully employed to resolve unsettled issues of law. However, in many contexts a full understanding of a state’s legal standard may be achieved only by seeing how a state’s highest court would apply that standard to the specific facts of a case. I think that is so in this case, and I would have been extremely interested to see how the New York Court of Appeals would have applied its failure-to-warn standard to the facts of Liriano’s injury resulting from his somehow placing his hand into the spout of Hobart’s meat-grinder from which the safety guard had been removed long after Hobart sold the product. Nevertheless, in the absence of a definitive Court of Appeals answer to our second question, we, as a diversity court, must make our best prediction as to how New York courts would answer that question had this case been tried in a state court. I am in considerable doubt as to what that prediction should be, but for reasons similar to those set forth by the majority, I agree that the New York Court of Appeals would most likely permit the liability issue in this case to be decided by a jury, and I therefore concur.

Like the majority, I see no need to decide how this ease would have been resolved had Hobart manufactured its meat-grinder without a safety guard — the circular plate above the spout with holes large enough for pieces of meat but small enough to prevent insertion of a hand. Instead, the issue for us is whether a New York court would permit a jury to consider liability for failure to warn of the danger of using the meat-grinder after a safety guard, originally installed, has been removed. Some might think it should make no difference whether a safety guard was originally installed so long as the machine the user confronts lacks such a guard. After all, the obviousness of the danger of placing one’s hand into the unguarded spout of a meat-grinder is the same for a person using a machine that was never equipped with a guard as for a person using a machine manufactured with a guard that was later removed. But the circumstances confronting the user of these two machines vary in two respects potentially relevant to the issue in this case.

First, if the second machine visibly indicates that it once was equipped with a safety guard, the user is alerted to the danger of using the machine without a device that the manufacturer thought was advisable for enhancing safety. For example, if the safety guard was attached by some form of latch, the opening of which permitted removal of the guard, and if the latch bore the legend “lock safety guard here,” the user of a machine from which the guard had been un*274latched and removed could reasonably be found by a jury to have had his appreciation of the danger enhanced, beyond what he should reasonably have perceived simply by seeing the open spout and knowing what happens to objects placed into that spout. To whatever extent such enhanced appreciation of the risk is relevant, it undermines the plaintiffs claim, since a manufacturer need not warn of an obvious risk and certainly need not do so as to a risk that is even more obvious than the risk presented by a machine that was never equipped with a guard. The tendency of a removed guard to enhance the user’s awareness of the risk is uncertain in this case, however, because the safety guard that was originally installed was not secured by a latch (and there was no legend concerning its attachment). Instead, is was bolted to the meat-grinder, and the record is unclear as to what conclusion, if any, a user could reasonably draw from the appearance of the machine as to the previous existence of a guard.

The second circumstance implicated by the previous existence of a safety guard is the one discussed in the Court’s opinion — the availability of the option of insisting upon a machine that has a guard, rather than facing only the choice between using a machine with a guard and not using the machine that lacks a guard. The Court’s opinion offers the example of a steep road marked in one instance with a sign that warns “Danger — Steep Grade” and in another instance with a more informative sign indicating the option of an alternate route that avoids the steep grade. The example is not precisely analogous to our case because the record gives no indication that an alternate machine with a safety guard was as readily available as an alternate driving route. Moreover, the option of a driver to choose an indicated alternate driving route immediately available is more realistic than the option of a supermarket employee to insist on a machine the availability of which is entirely uncertain. Nevertheless, the Court’s analogy usefully indicates a circumstance common to both the Court’s example and our case: the alternate means of proceeding more safely is an option known to the entity that bears a relationship to the dangerous condition and is not known to the person encountering the danger. When that disparity of knowledge exists, may liability be imposed by a fact-finder for failure to warn of the alternative?

This becomes the critical question in this case, and we have no firm basis on which to predict the answer New York’s highest court would give to it. An injury occurring as a result of a rather obvious danger but one that might have been avoided by an alternative known to a product manufacturer and not known to a likely user of the product has not been considered by the New York Court of Appeals, and appears not to have been directly confronted by other New York courts. Perhaps the most relevant clue is the observation that the Court of Appeals made in its response' to our first question in this case: “where reasonable minds might disagree as to the extent of the plaintiffs knowledge of the hazard, the question is one for the jury.” Liriano v. Hobart Corp., 92 N.Y.2d 232, 241, 677 N.Y.S.2d 764, 769, 700 N.E.2d 303, 308 (1998). I am not sure that reasonable minds could differ as to the extent of a store employee’s knowledge of the hazard of placing his hand in the open spout of a meat-grinder, but I think it likely that the Court of Appeals would rule that reasonable minds might differ on the closely related question concerning the extent of the employee’s knowledge of a safer alternative, i. e., avoiding use of a machine from which a safety guard had been removed and requesting a machine with the guard in place. For that reason, and in the absence of the clear answer we requested from the Court of Appeals, I agree that Liriano’s case was properly submitted to a jury for its decision.

One final comment is warranted. Those who believe that every decision in human affairs is a rational one, influenced logically by the incentives and disincentives that inhere in a given set of circumstances, will think it perverse that a manufacturer can be liable for failure to warn about the hazard of a meat-grinder originally equipped with a safety guard that has subsequently been removed even though liability might not exist had no such guard been initially installed. Surely, the devout rationalists will say, a rule of law countenancing such seemingly contra*275dictory results will create an incentive for meat-grinder manufacturers not to install safety guards in the first place, thereby obtaining at least the chance to escape liability that, under today’s decision, is deemed appropriate for jury consideration. I acknowledge that the disincentive to install a safety guard might exist, but, as with many predictions made on the assumption that a disincentive to take action will result in the action not being taken (or that an incentive to take action will result in the action being taken), I think it is extremely doubtful that meat-grinder manufacturers will elect to forgo safety guards in the hope of avoiding failure-to-warn liability for meat-grinders from which such guards have been removed. We have been well advised that the life of the law is not logic but experience, see Oliver Wendell Holmes, Jr., The Common Law 1 (Little, Brown & Co. 1990)(1891), and it is often the case that the life of life itself is not logic. Though rationality guides many human actions, it does not guide them all. Despite the disincentive arguably created by the imposition of liability in this case, manufacturers might well elect to install safety guards simply because they have some concern (humanitarian, not economic) that hands should not be severed by their machines. Moreover, if our decision correctly predicts New York law, manufacturers of meat-grinders equipped with safety guards can readily avoid liability for injuries resulting from use after the guard has been removed by the inexpensive furnishing of some reasonable form of notice of the hazard of using the machine without the guard. Hobart has already acted in this direction by placing on its machine a warning against use if the safety guard has been removed. Thus, the circumstances giving rise to Hobart’s liability in this case are unlikely to arise again.

For all of these reasons, I concur.

Affirmed by published opinion. Chief Judge WILKINSON wrote the opinion, in which Judge WIDENER and Judge KING joined.

OPINION

WILKINSON, Chief Judge:

Wilson M. Hood lost part of his thumb and lacerated his leg when he removed the blade guards from his new Ryobi miter saw and then used the unguarded saw for home carpentry. Hood sued Ryobi, alleging that the company failed adequately to warn of the saw’s dangers and that the saw was defective. Applying Maryland products liability law, the district court granted summary judgment to Ryobi on all claims.

The saw and owner’s manual bore at least seven clear, simple warnings not to operate the tool with the blade guards removed. The warnings were not required to spell out all the consequences of improper use. Nor was the saw defective — Hood altered and used the tool in violation of Ryobi’s clear warnings. Thus we affirm the judgment.

I.

Hood purchased a Ryobi TS-254 miter saw in Westminster, Maryland on February 25, 1995, for the purpose of performing home repairs. The saw was fully assembled at the time of purchase. It had a ten-inch diameter blade mounted on a rotating spindle controlled by a finger trigger on a handle near the top of the blade. To operate the saw, the consumer would use that handle to lower the blade through the material being cut.

Two blade guards shielded nearly the entire saw blade. A large metal guard, fixed to the frame of the saw, surrounded the upper half of the blade. A transparent plastic lower guard covered the rest of the blade and retracted into the upper guard as the saw came into contact with the work piece.

A number of warnings in the operator’s manual and affixed to the saw itself stated that the user should operate the saw only with the blade guards in place. For example, the owner’s manual declared that the user should “KEEP GUARDS IN PLACE” and warned: “ALWAYS USE THE SAW BLADE GUARD. Never operate the machine with the guard removed”; “NEVER operate this saw without all guards in place and in good operating condition”; and “WARNING: TO PREVENT POSSIBLE SERIOUS PERSONAL INJURY,NEVER PERFORM ANY CUTTING OPERATION WITH THE UPPER OR LOWER BLADE GUARD REMOVED.” The saw itself carried several decals stating “DANGER: DO NOT REMOVE ANY *610GUARD. USE OF SAW WITHOUT THIS GUARD WILL RESULT IN SERIOUS INJURY”; . “OPERATE ONLY WITH GUARDS IN PLACE”; and “WARNING ... DO NOT operate saw without the upper and lower guards in place.”

The day after his purchase, Hood began working with the saw in his driveway. While attempting to cut a piece of wood approximately four inches in height Hood found that the blade guards prevented the saw blade from passing completely through the piece. Disregarding the manufacturer’s warnings, Hood decided to remove the blade guards from the saw. Hood first detached the saw blade from its spindle. He then unscrewed the four screws that held the blade guard assembly to the frame of the saw. Finally, he replaced the blade onto the bare spindle and completed his cut.

Rather than replacing the blade guards, Hood continued to work with the saw blade exposed. He worked in this fashion for about twenty minutes longer when, in the middle of another cut, the spinning saw blade flew off the saw and back toward Hood. The blade partially amputated his left thumb and lacerated his right leg.

Hood admits that he read the owner’s manual and most of the warning labels on the saw before he began his work. He claims, however,.that he believed the blade guards were intended solely to prevent a user’s clothing or fingers from coming into contact with the saw. blade. He contends that he was unaware that removing the blade guards would permit the spinning blade to detach from the saw. But Ryobi, he claims, was aware of that possibility. In fact, another customer had sued Ryobi after suffering a similar accident in the mid-1980s.

On December 5, 1997, Hood sued several divisions of Ryobi in the United States District Court for the District of Maryland. Hood raised claims of failure to warn and defective design under several theories of liability. On cross-motions for summary judgment the district court entered judgment for the defendants on all claims, finding that in the face of adequate warnings Hood had altered the saw and caused his own injury. Hood v. Ryobi N. Am., Inc., 17 F.Supp.2d 448 (D.Md.1998). Hood appeals.

II.

A manufacturer may be liable for placing a product on the market that bears inadequate instructions and warnings or that is defective in design. Moran v. Faberge, Inc., 273 Md. 538, 332 A.2d 11, 15 (1975); Simpson v. Standard Container Co., 72 Md.App. 199, 527 A.2d 1337, 1339-40 (Ct.Spec.App.1987). Hood asserts that Ryobi failed adequatély to warn of the dangers of using the saw without the blade guards in place. Hood also contends that the design of the saw was defective. We disagree on both counts.1

A.

Hood first complains that the warnings he received were insufficiently specific. Hood admits that Ryobi provided'several clear and conspicuous warnings not to operate the saw without the blade guards. He contends, however, that the warnings affixed to the product and displayed in the operator’s manual were inadequate to alert him to the dangers of doing so. In addition to Ryobi’s directive “never” to operate a guardless saw, Hood would require the company to inform of the actual consequences of such conduct. Specifically, Hood contends that an adequate warning would have explained that removing the guards would lead to blade detachment.

We disagree. Maryland does not require an encyclopedic warning. Instead, “a warning need only be one that is rea*611sonable under the circumstances.” Levin v. Walter Kidde & Co., 251 Md. 560, 248 A.2d 151, 153 (1968). A clear and specific warning will normally be sufficient — “the manufacturer need not warn of every mishap or source of injury that the mind can imagine flowing from the product.” Liesener v. Weslo, Inc., 775 F.Supp. 857, 861 (D.Md.1991); see Levin, 248 A.2d at 154 (declining to require warning of the danger that a cracked syphon bottle might explode and holding “never use cracked bottle” to be adequate as a matter of law). In deciding whether a warning is adequate, Maryland law asks whether the benefits of a more detailed warning outweigh the costs of requiring the change. Moran, 332 A.2d at 15.

Hood assumes that the cost of a more detailed warning label is minimal in this case, and he claims that such a warning would have prevented his injury. But the price of more detailed warnings is greater than their additional printing fees alone. Some commentators have observed that the proliferation of label detail threatens to undermine the effectiveness of warnings altogether. See James A. Henderson, Jr. & Aaron D. Twerski, Doctrinal Collapse in Products Liability: The Empty Shell of Failure to Warn, 65 N.Y.U. L.Rev. 265, 296-97 (1990). As manufacturers append line after line onto product labels in the quest for the best possible warning, it is easy to lose sight of the label’s communicative value as a whole. Well-meaning attempts to warn of every possible accident lead over time to voluminous yet impenetrable labels — too prolix to read and too technical to understand.

By contrast, Ryobi’s warnings are clear and unequivocal. Three labels on the saw itself and at least four warnings in the owner’s manual direct the user not to operate the saw with the blade guards removed. Two declare that “serious injury” could result from doing so. This is not a case where the manufacturer has failed to include any warnings at all with its product. See Moran, 332 A.2d at 13-14. Ryobi provided warnings sufficient to apprise the ordinary consumer that it is unsafe to operate a guardless saw — warnings which, if followed, would have prevented the injury in this case.

It is apparent, moreover, that the vast majority of consumers do not detach this critical safety feature before using this type of saw. Indeed, although Ryobi claims to have sold thousands of these saws, Hood has identified only one fifteen-year-old incident similar to his. Hood has thus not shown that these clear, unmistakable, and prominent warnings are insufficient to accomplish their purpose. Nor can he prove that increased label clutter would bring any net societal benefit. We hold that the warnings Ryobi provided are adequate as a matter of law.

B.

Hood’s defective design claim is likewise unpersuasive. Hood’s injuries were the direct result of the alterations he made to the saw — alterations that directly contravened clear, unambiguous warnings. And such alterations defeat a claim of design defect.2

This rule has been expressed alternatively as one of duty and one of causation. First, a manufacturer is only required to design a product that is safe for its reasonably foreseeable uses. If that duty is met, the product is simply not defective. Banks v. Iron Hustler Corp., *612475 A.2d 1243, 1255 (Md.Ct.Spec.App.1984). Second, if a consumer alters a product in a way that creates a defect, the consumer’s conduct rather than the manufacturer’s is the proximate cause of any ensuing accident. See id. at 1253-55; Singleton v. Manitowoc Co., 727 F.Supp. 217, 222 (D.Md.1989), aff'd, 931 F.2d 887 (4th Cir.1991) (table). Under either rationale, a post-sale product alteration will defeat a design defect claim if that alteration leads directly to the plaintiffs injury.

Hood admits that he altered the table saw by removing the blade guards from the unit’s frame, and he acknowledges that the alteration led directly to his injuries. Hood asserts, however, that Ryobi should have foreseen that consumers might operate its saws with the guards removed. Hood notes that the operation of equipment without safety guards is a frequently cited OSHA violation. And, as noted, Ryobi itself has faced litigation on one other occasion for the same type of accident that befell Hood. In short, Hood contends that Ryobi should have designed its saw to operate equally well with the guards in place or removed.

We disagree. Maryland imposes no duty to predict that a consumer will violate clear, easily understandable safety warnings such as those Ryobi included with this product. For example, a manufacturer need not foresee that a consumer might store a gasoline can in his basement in contravention of clear warning labels. Simpson, 527 A.2d at 1341 (“ ‘Where warning is given, the seller may reasonably assume that it will be read and heeded; and a product bearing such a warning, which is safe for use if it is followed, is not in defective condition, nor is it unreasonably dangerous.’” (quoting Restatement (Second) of Torts § 402A cmt. j)). Nor must a manufacturer foresee that a worker will shove his arm into a conveyor machine to repair it without first shutting the machine down, again in violation of “explicit written warnings.” Kline v. ABCO Engineering Corp., 991 F.Supp. 747, 750-51 (D.Md.1997). When a consumer injures himself by using a product — or, as in this case, by altering it — in violation of clear, unmistakable, and easy-to-follow warnings, it is the consumer’s own conduct that causes the injury. Id.; see Higgins v. E.I. DuPont de Nemours & Co., 863 F.2d 1162, 1167-68 (4th Cir.1988). The manufacturer is not liable under a design defect theory.

We recognize that the American Law Institute has recently underscored the concern that comment j of the Second Restatement, read literally, would permit a manufacturer of a dangerously defective product to immunize itself from liability merely by slapping warning labels on that product. See Restatement (Third) of Torts: Prod. Liab. § 2 cmt. 1 & Reporter’s Note. We are all afflicted with lapses of attention; warnings aimed simply at avoiding consumer carelessness should not absolve a manufacturer of the duty to design reasonable safeguards for its products. See id. cmt. 1, illus. 14 (when warning could not eliminate the possibility of accidental contact with a dangerous shear point, decal declaring “keep hands and feet away” does not bar a design defect claim).

The Maryland courts have already made clear, however, that warnings will not inevitably defeat liability for a product’s defective design. See Klein v. Sears, Roebuck & Co., 92 Md.App. 477, 608 A.2d 1276, 1282-83 (Ct.Spec.App.1992) (such warnings as “never leave tool running unattended” and “do not place fingers or hands in the path of the saw blade” are too vague to defeat manufacturer’s liability for failing to include blade guards on its saws). Maryland has thus sought to encourage manufacturers to rid their products of traps for the unwary, while declining to hold them responsible for affirmative consumer misuse.

This case involves much more than a consumer’s inevitable inattention. Rather, Hood took affirmative steps to remove the safety, guards from his saw and — in contravention of warnings which were “clear, *613direct, simple, unequivocal!], unmistakable, definite, and easy to understand and obey” — then used the saw to cut several pieces of wood. Klein, 608 A.2d at 1282. Hood’s own conduct thus caused his injury and defeats any claim that the saw is defective in design.

III.

Warned never to operate his miter saw without the blade guards in place, Hood nonetheless chose to detach those guards and run the saw in a disassembled condition. We hold that Ryobi is not hable for Hood’s resulting injuries under any of the theories of recovery raised here. The judgment of the district court is therefore

AFFIRMED.

*730Opinion

RICHARDSON, J.

The most important of several problems which we consider is whether the principles of comparative negligence expressed by us in Li v. Yellow Cab Co. (1975) 13 Cal.3d 804 [119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393], apply to actions founded on strict products liability. We will conclude that they do. We also inquire whether evidence of “compensating” safety devices installed in a motor vehicle by its manufacturer is admissible to offset alleged design deficiencies, and whether, under the particular facts herein, evidence of a driver’s claimed intoxication or of his asserted failure to use his vehicle’s safety equipment may be considered. While agreeing that evidence of compensating design characteristics is admissible, we will further determine that under the circumstances herein prejudicial error requiring reversal occurred upon the admission of evidence of the decedent’s alleged intoxication and failure to use safety devices in his vehicle.

The Facts And The Trial

Although there were no eyewitnesses, the parties agree, generally, on the reconstruction of the accident in question. In the early hours of October 31, 1970, decedent Kirk Daly, a 36-year-old attorney, was driving his Opel southbound on the Harbor Freeway in Los Angeles. The vehicle, while travelling at a speed of 50-70 miles per hour, collided with and damaged 50 feet of metal divider fence. After the initial impact between the left side of the vehicle and the fence the Opel spun counterclockwise, the driver’s door was thrown open, and Daly was forcibly ejected from the car and sustained fatal head injuries. It was equally undisputed that had the deceased remained in the Opel his injuries, in all probability, would have been relatively minor.

Plaintiffs, who are decedent’s widow and three surviving minor children, sued General Motors Corporation, Boulevard Buick, Underwriter’s Auto Leasing, and Aleo Leasing Company, the successive links in the Opel’s manufacturing and distribution chain. The sole theory of plaintiffs’ complaint was strict liability for damages allegedly caused by a defective product, namely, an improperly designed door latch claimed to have been activated by the impact. It was further asserted that, but for the faulty latch, decedent would have been restrained in the vehicle and, although perhaps injured, would not have been killed. Thus, the case involves a so-called “second collision” in which the “defect” did not *731contribute to the original impact, but only to the “enhancement” of injury.

At trial the jury heard conflicting expert versions as to the functioning of the latch mechanism during the accident. Plaintiffs’ principal witness testified that the Opel’s door was caused to open when the latch button on the exterior handle of the driver’s door was forcibly depressed by some protruding portion of the divider fence. It was his opinion that the exposed push button on the door constituted a design “defect” which caused injuries greatly in excess of those which Daly would otherwise have sustained. Plaintiffs also introduced evidence that other vehicular door latch designs used in production models of the same and prior years afforded substantially greater protection. Defendants’ experts countered with their opinions that the force of the impact was sufficiently strong that it would have caused the door to open resulting in Daly’s death even if the Opel had been equipped with door latches of the alternative designs suggested by plaintiffs.

Over plaintiffs’ objections, defendants were permitted to introduce evidence indicating that: (1) the Opel was equipped with a seat belt-shoulder harness system, and a door lock, either of which if used, it was contended, would have prevented Daly’s ejection from the vehicle; (2) Daly used neither the harness system nor the lock; (3) the 1970 Opel owner’s manual contained warnings that seat belts should be worn and doors locked when the car was in motion for “accident security”; and (4) Daly was intoxicated at the time of collision, which evidence the juiy was advised was admitted for the limited purpose of determining whether decedent had used the vehicle’s safety equipment. After relatively brief deliberations the jury returned a verdict favoring all defendants, and plaintiffs appeal from the ensuing adverse judgment.

Strict Products Liability And Comparative Fault

In response to plaintiffs’ assertion that the “intoxication-nonuse” evidence was improperly admitted, defendants contend that the deceased’s own conduct contributed to his death. Because plaintiffs’ case rests upon strict products liability based on improper design of the door latch and because defendants assert a failure in decedent’s conduct, namely, his alleged intoxication and nonuse of safety equipment, without which the accident and ensuing death would not have occurred, there is *732thereby posed the overriding issue in the case, should comparative principles apply in strict products liability actions?

It may be useful to refer briefly to certain highlights in the historical development of the two principles—strict and comparative liability. Tort law has evolved from a legal obligation initially imposed without “fault,” to recovery which, generally, was based on blameworthiness in a moral sense. For reasons of social policy and because of the unusual nature of defendants’ acts, liability without fault continued to be prescribed in a certain restricted area, for example, upon keepers of wild animals, or those who handled explosives or other dangerous substances, or who engaged in ultrahazardous activities. Simultaneously, and more particularly, those who were injured in the use of personal property were permitted recovery on a contract theory if they were the purchasers of the chattel or were in privity. Subsequently, liability was imposed in negligence upon the manufacturer of personalty in favor of the general consumer. (For a comprehensive historical review, see Prosser, Law of Torts (4th ed. 1971) § 96, pp. 641-644; 2 Harper & James, The Law of Torts (1956) § 12.2 and foll., p. 747 and foll.) Evolving social policies designed to protect the ultimate consumer soon prompted the extension of legal responsibility beyond negligence to express or implied warranty. Thus, in the area of food and drink a form of strict liability predicated upon warranty found wide acceptance. Warranty actions, however, contained their own inherent limitations requiring a precedent notice to the vendor of a breach of the warranty, and absolving him from loss if he had issued an adequate disclaimer.

General dissatisfaction continued with the conceptual limitations which traditional tort and contract doctrines placed upon the consumers and users of manufactured products, this at a time when mass production of an almost infinite variety of goods and products was responding to a myriad of ever-changing societal demands stimulated by wide-spread commercial advertising. From an historic combination of economic and sociological forces was bom the doctrine of strict liability in tort.

We, ourselves, were perhaps the first court to give the new principle judicial sanction. In Greenman v. Yuba Power Products, Inc. (1963) 59 Cal.2d 57 [27 Cal.Rptr. 697, 377 P.2d 897, 13 A.L.R.3d 1049], confronted with injuiy to an ultimate consumer caused by a defective power tool, we fastened strict liability on a manufacturer who placed on the market a defective product even though both privity and notice of breach of warranty were lacking. We rejected both contract and warranty theories, *733express or implied, as the basis for liability. Strict liability, we said, did not rest on a consensual foundation but, rather, on one created by law. The liability was created judicially because of the economic and social need for the protection of consumers in an increasingly complex and mechanized society, and because of the limitations in the negligence and warranty remedies. Our avowed purpose was “to insure that the costs of injuries resulting from defective products are borne by the manufacturer that put such products on the market rather than by the injured persons who are powerless to protect themselves.” (Id., at p. 63.) Subsequently, the Greenman principle was incorporated in section 402A of the Restatement Second of Torts, and adopted by a majority of American jurisdictions. (Prosser, supra, at pp. 657-658.)

From its inception, however, strict liability has never been, and is not now, absolute liability. As has been repeatedly expressed, under strict liability the manufacturer does not thereby become the insurer of the safety of the product’s user. (Cronin v. J. B. E. Olson Corp. (1972) 8 Cal.3d 121, 133 [104 Cal.Rptr. 433, 501 P.2d 1153]; Dippel v. Sciano (1967) 37 Wis.2d 443 [155 N.W.2d 55, 63]; West v. Caterpillar Tractor Company, Inc. (Fla. 1976) 336 So.2d 80, 90; Traynor, The Ways and Meanings of Defective Products and Strict Liability (1965) 32 Tenn.L.Rev. 363, 366-367.) On the contrary, the plaintiff’s injury must have been caused by a “defect” in the product. Thus the manufacturer is not deemed responsible when injury results from an unforeseeable use of its product. (Cronin, supra, at p. 126; Rest.2d Torts, supra, coms. g, h.) Furthermore, we have recognized that though most forms of contributory negligence do not constitute a defense to a strict products liability action, plaintiff’s negligence is a complete defense when it comprises assumption of risk. (Luque v. McLean (1972) 8 Cal.3d 136, 145 [104 Cal.Rptr. 443, 501 P.2d 1163]; Rest.2d Torts, § 402A, com. b.) As will thus be seen, the concept of strict products liability was created and shaped judicially. In its evolution, the doctrinal encumbrances of contract and warranty, and the traditional elements of negligence, were stripped from the remedy, and a new tort emerged which extended liability for defective product design and manufacture beyond negligence but short of absolute liability.

In Li v. Yellow Cab Co., supra, 13 Cal.3d 804, we introduced the other doctrine with which we are concerned, comparative negligence. We examined the history of contributory negligence, the massive criticism directed at it because its presence in the slightest degree completely barred plaintiff’s recovery, and the increasing defection from the doctrine. We then weighed the two principal arguments against its *734removal from California law, namely, that such a sharp change in direction required legislative action, and that there existed a cluster of asserted practical obstacles relating to multiple parties, the apportionment burdens on a jury and the uncertain effect on the defenses of last clear chance, assumption of risk, and wilful misconduct. Concluding that none of the obstacles was insurmountable, we announced in Li the adoption of a “pure” form of comparative negligence which, when present, reduced but did not prevent plaintiff’s recovery. (Pp. 828-829.) We held that the defense of assumption of risk, insofar as it is no more than a variant of contributory negligence, was merged into the assessment of liability in proportion to fault. (Pp. 824-825.) Within the broad guidelines therein announced, we left to trial courts discretion in the particular implementation of the new doctrine. (Pp. 826-827.)

We stand now at the point of confluence of these two conceptual streams, having been greatly assisted by the thoughtful analysis of the parties and the valuable assistance of numerous amici curiae. We are by no means the first to consider the interaction of these two developing principles.. As with the litigants before us, responsible and respected authorities have reached opposing conclusions stressing in various degrees the different considerations which we now examine.

Those counseling against the recognition of comparative fault principles in strict products liability cases vigorously stress, perhaps equally, not only the conceptual, but also the semantic difficulties incident to such a course. The task of merging the two concepts is said to be impossible, that “apples and oranges” cannot be compared, that “oil and water” do not mix, and that strict liability, which is not founded on negligence or fault, is inhospitable to comparative principles. The syllogism runs, contributory negligence was only a defense to negligence, comparative negligence only affects contributory negligence, therefore comparative negligence cannot be a defense to strict liability. (See Butaud v. Suburban Marine & Sport. Goods, Inc. (Alaska 1976) 555 P.2d 42, 47 (dis. opn. by Burke, J.), noted by Masin (1977) 4 Western St.U. L.Rev. 283, 284.) While fully recognizing the theoretical and semantic distinctions between the twin principles of strict products liability and traditional negligence, we think they can be blended or accommodated.

The inherent difficulty in the “apples and oranges” argument is its insistence on fixed and precise definitional treatment of legal concepts. In the evolving areas of both products liability and tort defenses, *735however, there has developed much conceptual overlapping and interweaving in order to attain substantial justice. The concept of strict liability itself, as we have noted, arose from dissatisfaction with the wooden formalisms of traditional tort and contract principles in order to protect the consumer of manufactured goods. Similarly, increasing social awareness of its harsh “all or nothing” consequences led us in Li to moderate the impact of traditional contributory negligence in order to accomplish a fairer and more balanced result. We acknowledged an intermixing of defenses of contributoiy negligence and assumption of risk and formally effected a type of merger, “As for assumption of risk, we have recognized in this state that this defense overlaps that of contributory negligence to some extent . . . .” (Li, supra, at p. 824.) In Li, we further reaffirmed our observation in Grey v. Fibreboard Paper Products Co. (1966) 65 Cal.2d 240, 245 [53 Cal.Rptr. 545, 418 P.2d 153]: “ ‘[T]hat in one kind of situation, to wit, where a plaintiff unreasonably undertakes to encounter a specific known risk imposed by a defendant’s negligence, plaintiff’s conduct, although he may encounter that risk in a prudent manner, is in reality a form of contributoiy negligence . . . .’ We think it clear that the adoption of a system of comparative negligence should entail the merger of the defense of assumption of risk into the general scheme of assessment of liability in proportion to fault in those particular cases in which the form of assumption of risk involved is no more than a variant of contributory negligence.” (13 Cal.3d at pp. 824-825, quoting Grey, supra, at pp. 245-246, italics in original.)

Furthermore, the “apples and oranges” argument may be conceptually suspect. It has been suggested that the term “contributory negligence,” one of the vital building blocks upon which much of the argument is based, may indeed itself be a misnomer since it lacks the first element of the classical negligence formula, namely, a duty of care owing to another. A highly respected torts authority, Dean William Prosser, has noted this fact by observing, “It is perhaps unfortunate that contributory negligence is called negligence at all. ‘Contributoiy fault’ would be a more descriptive term. Negligence as it is commonly understood is conduct which creates an undue risk of harm to others. Contributoiy negligence is conduct which involves an undue risk of harm to the actor himself. Negligence requires a duty, an obligation of conduct to another person. Contributory negligence involves no duty, unless we are to be so ingenious as to say that the plaintiff is under an obligation to protect the defendant against liability for the consequences of his own negligence.” (Prosser, Law of Torts, supra, § 65, p. 418.)

*736We think, accordingly, the conclusion may fairly be drawn that the terms “comparative negligence,” “contributory negligence” and “assumption of risk” do not, standing alone, lend themselves to the exact measurements of a micrometer-caliper, or to such precise definition as to divert us from otherwise strong and consistent counterváiling policy considerations. Fixed semantic consistency at this point is less important than the attainment of a just and equitable result. The interweaving of concept and terminology in this area suggests a judicial posture that is flexible rather than doctrinaire.

We pause at this point to observe that where, as here, a consumer or user sues the manufacturer or designer alone, technically, neither fault nor conduct is really compared functionally. The conduct of one party in combination with the product of another, or perhaps the placing of a defective article in the stream of projected and anticipated use, may produce the ultimate injury. In such a case, as in the situation before us, we think the term “equitable apportionment or allocation of loss” may be more descriptive than “comparative fault.”

Given all of the foregoing, we are, in the wake of Li, disinclined to resolve the important issue before us by the simple expedient of matching linguistic labels which have evolved either for convenience or by custom. Rather, we consider it more useful to examine the foundational reasons underlying the creation of strict products liability in California to ascertain whether the purposes of the doctrine would be defeated or diluted by adoption of comparative principles. We imposed strict liability against the manufacturer and in favor of the user or consumer in order to relieve injured consumers “from problems of proof inherent in pursuing negligence . . . and warranty . . . remedies, . . .” (Cronin v. J. B. E. Olson Corp., supra, 8 Cal.3d at p. 133, italics added; Greenman v. Yuba Power Products, Inc., supra, 59 Cal.2d at p. 63; Escola v. Coca Cola Bottling Co. (1944) 24 Cal.2d 453, 461-462 [150 P.2d 436] (conc. opn. by Traynor, J.).) As we have noted, we sought to place the burden of loss on manufacturers rather than “... injured persons who are powerless to protect themselves . . . .” (Greenman, supra, at p. 63; italics added; see Escola, supra, at p. 462; Price v. Shell Oil Co. (1970) 2 Cal.3d 245, 251 [85 Cal.Rptr. 178, 466 P.2d 722] [“protection of otherwise defenseless victims of manufacturing defects and the spreading throughout society of the cost of compensating them”] italics added.)

The foregoing goals, we think, will not be frustrated by the adoption of comparative principles. Plaintiffs will continue to be relieved of proving *737that the manufacturer or distributor was negligent in the production, design, or dissemination of the article in question. Defendant’s liability for injuries caused by a defective product remains strict. The principle of protecting the defenseless is likewise preserved, for plaintiff’s recovery will be reduced only to the extent that his own lack of reasonable care contributed to his injury. The cost of compensating the victim of a defective product, albeit proportionately reduced, remains on defendant manufacturer, and will, through him, be “spread among society.” However, we do not permit plaintiff’s own conduct relative to the product to escape unexamined, and as to that share of plaintiff’s damages which flows from his own fault we discern no reason of policy why it should, following Li, be borne by others. Such a result would directly contravene the principle announced in Li, that loss should be assessed equitably in proportion to fault.

We conclude, accordingly, that the expressed purposes which persuaded us in the first instance to adopt strict liability in California would not be thwarted were we to apply comparative principles. What would be forfeit is a degree of semantic symmetry. However, in this evolving area of tort law in which new remedies are judicially created, and old defenses judicially merged, impelled by strong considerations of equity and fairness we seek a larger synthesis. If a more just result follows from the expansion of comparative principles, we have no hesitancy in seeking it, mindful always that the fundamental and underlying purpose of Li was to promote the equitable allocation of loss among all parties legally responsible in proportion to their fault.

A second objection to the application of comparative principles in strict products liability cases is that a manufacturer’s incentive to produce safe products will thereby be reduced or removed. While we fully recognize this concern we think, for several reasons, that the problem is more shadow than substance. First, of course, the manufacturer cannot avoid its continuing liability for a defective product even when the plaintiff’s own conduct has contributed to his injury. The manufacturer’s liability, and therefore its incentive to avoid and correct product defects, remains; its exposure will be lessened only to the extent that the trier finds that the victim’s conduct contributed to his injury. Second, as a practical matter a manufacturer, in a particular case, cannot assume that the user of a defective product upon whom an injury is visited will be blameworthy. Doubtless, many users are free of fault, and a defect is at least as likely as not to be exposed by an entirely innocent plaintiff who will obtain full recovery. In such cases the manufacturer’s *738incentive toward safety both in design and production is wholly unaffected. Finally, we must observe that under the present law, which recognizes assumption of risk as a complete defense to products liability, the curious and cynical message is that it profits the manufacturer to make his product so defective that in the event of injury he can argue that the user had to be aware of its patent defects. To that extent the incentives are inverted. We conclude, accordingly, that no substantial or significant impairment of the safety incentives of defendants will occur by the adoption of comparative principles.

In passing, we note one important and felicitious result if we apply comparative principles to strict products liability. This arises from the fact that under present law when plaintiff sues in negligence his own contributory negligence, however denominated, may diminish but cannot wholly defeat his recovery. When he sues in strict products liability, however, his “assumption of risk” completely bars his recovery. Under Li, as we have noted, “assumption of risk” is merged into comparative principles. (13 Cal.3d at p. 825.) The consequence is that after Li in a negligence action, plaintiff’s conduct which amounts to “negligent” assumption of risk no longer defeats plaintiff’s recovery. Identical conduct, however, in a strict liability case acts as a complete bar under rules heretofore applicable. Thus, strict products liability, which was developed to free injured consumers from the constraints imposed by traditional negligence and warranty theories, places a consumer plaintiff in a worse position than would be the case were his claim founded on simple negligence. This, in turn, rewards adroit pleading and selection of theories. The application of comparative principles to strict liability obviates this bizarre anomaly by treating alike the defenses to both negligence and strict products liability actions. In each instance the defense, if established, will reduce but not bar plaintiff’s claim.

A third objection to the merger of strict liability and comparative fault focuses on the claim that, as a practical matter, triers of fact, particularly jurors, cannot assess, measure, or compare plaintiff’s negligence with defendant’s strict liability. We are unpersuaded by the argument and are convinced that jurors are able to undertake a fair apportionment of liability.

We are strengthened in the foregoing conclusion by the federal experience under the maritime doctrine of “unseaworthiness.” For decades, seamen have been permitted to recover from shipowners for injuries caused by defects rendering a vessel “unseaworthy.” (E.g., The *739 Osceola (1903) 189 U.S. 158, 175 [47 L.Ed. 760, 764, 23 S.Ct. 483].) As noted by many courts, the concept of “unseaworthiness” is not limited to or affected by notions of the shipowner’s fault or due care, but applies to any deficiency of hull, equipment or crew, regardless of cause, which renders the ship less than reasonably fit for its intended purposes. (Mitchell v. Trawler Racer, Inc. (1960) 362 U.S. 539, 550 [4 L.Ed.2d 941, 948, 80 S.Ct. 926]; Seas Shipping Co. v. Sieracki (1946) 328 U.S. 85, 94 [90 L.Ed. 1099, 1105-1106, 66 S.Ct. 872], rehg. den., 328 U.S. 878 [90 L.Ed. 1646, 66 S.Ct. 1116].) Nonetheless, comparative principles have been made applicable to suits brought under the “unseaworthiness” doctrine, a form of strict liability, and the degree to which plaintiff’s own negligence contributes to his injuries has been considered in determining the amount of his recovery. (Pope & Talbot, Inc. v. Hawn (1953) 346 U.S. 406, 408-409 [98 L.Ed. 143,150-151,74 S.Ct. 202].) No serious practical difficulties appear to have arisen even where jury trials are involved. (E.g., Price v. Mosler (5th Cir. 1973) 483 F.2d 275, 277-278.)

We find equally unpersuasive a final objection that the merger of the two principles somehow will abolish or adversely affect the liability of such intermediate entities in the chain of distribution as retailers (Vandermark v. Ford Motor Co. (1964) 61 Cal.2d 256, 263 [37 Cal.Rptr. 896, 391 P.2d 168]), and bailors (Price v. Shell Oil Co., supra, 2 Cal.3d 245, 253.) We foresee no such consequence. Regardless of the identity of a particular defendant or of his position in the commercial chain the basis for his liability remains that he has marketed or distributed a defective product. If, as we believe, jurors are capable of assessing fully and fairly the legal responsibility of a manufacturer on a strict liability basis, no reason appears why they cannot do likewise with respect to subsequent distributors and vendors of the product.

We note that the majority of our sister states which have addressed the problem, either by statute or judicial decree, have extended comparative principles to strict products liability.

Our research discloses that of the more than 30 states which have adopted some form of comparative negligence, three (including California) have done so judicially. The two other states, Alaska (Butaud v. Suburban Marine & Sport. Goods, Inc., supra, 555 P.2d 42, 46) and Florida (West v. Caterpillar Tractor Company, Inc., supra, 336 So.2d 80, 89-90) have likewise, judicially, extended comparative principles to strict liability actions. At least five states have adopted comparative fault statutes which are not limited in their language to negligence actions: *740Arkansas (Ark.Stat.Ann. §§ 27-1763-1765 (1975)); Maine (Me.Rev.Stat., tit. 14, § 156 (1965)); Mississippi (3 Miss. Code Ann. § 11-7-15 (1917)); New York (CPLR, art. 14-A, § 1411 (1975)); and Rhode Island (2A R.I. Gen. Laws, § 9-20-4 (1971)). The New York statute expressly applies to strict liability actions. (See CPLR, supra, art. 14-A, § 1411, Practice Commentaries, CP 1411:1.) The Mississippi statute has been judicially construed as extending to suits founded on strict products liability. (Edwards v. Sears, Roebuck and Company (5th Cir. 1975) 512 F.2d 276, 290.) On the other hand one state, Connecticut, has statutorily prohibited the use of comparative fault as a defense in strict liability actions. (Pub.L. No. 77-335, eff. July 1, 1977.)

Of the three decisions which have declined to apply comparative negligence to strict liability, two have noted their reliance on state comparative negligence statutes which are expressly confined to “negligence” actions. (Melia v. Ford Motor Co. (8th Cir. 1976) 534 F.2d 795, 802 [Nebraska “slight-gross” comparative negligence statute]; Kirkland v. General Motors Corporation (Okla. 1974) 521 P.2d 1353, 1367-1368 [noting the limiting statutory language but holding that driving while intoxicated was product misuse barring recovery]; see also Kinard v. Coats Company, Inc. (1976) — Colo.App. — [553 P.2d 835, 837].) At least three jurisdictions have applied comparative negligence statutes to strict liability actions, despite language arguably limiting the statute application to negligence. (Dippel v. Sciano, supra, 155 N.W.2d 55, 64; Sun Val. Airlines, Inc. v. Avco-Lycoming Corp. (D.Idaho 1976) 411 F.Supp. 598, 602-603; Hagenbuch v. Snap-On Tools Corp. (D.N.H. 1972) 339 F.Supp. 676, 681-683.) Finally, one court has judicially extended a “pure” form of comparative fault to the traditional strict liability defense of “product misuse,” despite the existence of a statutory scheme of “modified” comparative negligence. (General Motors Corp. v. Hopkins (Tex. 1977) 548 S.W.2d 344, 351-352.)

Moreover, we are further encouraged in our decision herein by noting that the apparent majority of scholarly commentators has urged adoption of the rule which we announce herein. These include, from the academic community: Wade, A Uniform Comparative Fault Act—What Should It Provide? (1977) 10 Mich. J. L. Ref. 220; Fleming, The Supreme Court of California 1974-1975—Foreword: Comparative Negligence at Last—By Judicial Choice (1976) 64 Cal.L.Rev. 239, 269-271; Schwartz, Comparative Negligence (1974) § 12.1 et seq., p. 195 et seq. (see also Special Cal. Supplement re Nga Li v. Yellow Cab Co. of California (1975) § 4(B), p. 8); Wade, On the Nature of Strict Tort Liability for Products (1973) 44 *741Miss.L.J. 825, 850; Noel, Defective Products; Abnormal Use, Contributory Negligence, and Assumption of Risk (1972) 25 Vand.L.Rev. 93, 117-118; contra, Levine, Strict Products Liability and Comparative Negligence: The Collision of Fault and No-Fault (1977) 14 San Diego L.Rev. 337, 346 et seq. Among other commentaries urging such a rule are: Posner et al., Comparative Negligence in California: Some Legislative Solutions—Part II (1977) Los Angeles Daily Journal Report (Aug. 26, 1977) at pages 4, 9-18 (proposed legislation); Brewster, Comparative Negligence In Strict Liability Cases (1976) 42 J. Air L. & Com. 107, 109-117; Comment, Comparative Negligence in Vermont: A Solution or a Problem (1976) 40 Albany L.Rev. 777, 810; Feinberg, The Applicability of a Comparative Negligence Defense in a Strict Products Liability Suit Based on Section 402A of the Restatement of Torts 2d (1975) 42 Ins.Couns.J. 39, 52; Comment, Tort Defenses to Strict Products Liability (1969) 20 Syracuse L.Rev. 924, 925; Epstein, Products Liability: Defenses Based on Plaintiff’s Conduct (1968) 1968 Utah L.Rev. 267, 284; Levine, Buyer’s Conduct as Affecting the Extent of Manufacturer’s Liability in Warranty (1968) 52 Minn.L.Rev. 627, 652-663; contra, Robinson, Square Pegs (Products Liability) In Round Holes (Comparative Negligence) (1977) 52 State Bar J. 16; Schwartz, Pure Comparative Negligence in Action (1972) 34 Am.Trial Law. J. 117, 129.

. We find additional significance in the provisions of the proposed Uniform Comparative Fault Act (Act), authored by Professor Wade, a recognized torts scholar, distinguished professor of law, and former dean, Vanderbilt University, current reporter of the Restatement Second of Torts, and chairman of the special committee on the Act of the National Conference of the Commissioners on Uniform States Laws (Conference). Our attention has been called to the action of the Conference in August 1977, wherein it approved adoption of the Act by a vote of 40 states to 8 (California voting favorably). The Act is the distillation of approximately five years of discussion, analysis, and contribution by a special committee and a review committee of the Conference. We quote portions of section 1 of the proposed Act: “Section 1. [Effect of Contributory Fault.] [H] (a) In an action based on fault to recover damages for injury or death to person or harm to property, any contributory fault chargeable to the claimant diminishes proportionately the amount awarded as compensatory damages for an injury attributable to the claimant’s contributory fault, but does not bar recovery .... [If] (b) ‘Fault’ includes acts or omissions that are in any measure negligent or reckless toward the person or property of the actor or others, or that subject a person to strict tort liability.” (Italics added.) While lacking any legislative sanction, the *742Act, in our view, points in the direction of a responsible national trend. As such, section 1 is revealing in two notable respects: in its clear definitional expression in subsection (b) that comparative principles are to be applied to cases of “strict tort liability,” and in its substitution of the broad generic term “fault,” in subsection (a), as including both negligence and strict liability.

Having examined the principal objections and finding them not insurmountable, and persuaded by logic, justice, and fundamental fairness, we conclude that a system of comparative fault should be and it is hereby extended to actions founded on strict products liability. In such cases the separate defense of “assumption of risk,” to the extent that it is a form of contributory negligence, is abolished. While, as we have suggested, on the particular facts before us, the term “equitable apportionment of loss” is more accurately descriptive of the process, nonetheless, the term “comparative fault” has gained such wide acceptance by courts and in the literature that we adopt its use herein.

In Li, we announced a system of pure comparative negligence “the fundamental purpose of which shall be to assign responsibility and liability for damage in direct proportion to the amount of negligence of each of the parties.” (13 Cal.3d, at p. 829.) Those same underlying considerations of policy which moved us judicially in Li to rescue blameworthy plaintiffs from a 100-year-old sanction against all recovery persuade us now to extend similar principles to the strict products liability area. Legal responsibility is thereby shared. We think that apportioning tort liability is sound, logical and capable of wider application than to negligence cases alone. To hold otherwise, in our view, would be to perpetuate a system which, as we noted in Li, Dean Prosser describes as placing “. . . upon one party the entire burden of a loss for which two are, by hypothesis, responsible.” (Prosser, supra, § 67, p. 433.) We reiterate that our reason for extending a full system of comparative fault to strict products liability is because it is fair to do so. The law consistently seeks to elevate justice and equity above the exact contours of a mathematical equation. We are convinced that in merging the two principles what may be lost in symmetiy is more than gained in fundamental fairness.

In Li we scrupulously abstained from issuing a detailed guidebook to the new area of comparative negligence, preferring to adopt the view of a Florida court that “. . . the trial judges of this State are capable of applying [a] comparative negligence rule without our setting guidelines *743in anticipation of expected problems. The problems are more appropriately resolved at the trial level in a practical manner instead of a theoretical solution at appellate level. The trial judges are granted broad discretion in adopting such procedure as may accomplish the objectives and purposes expressed in this opinion.” (Hoffman v. Jones (Fla. 1973) 280 So.2d 431, 439-440.) We reaffirm the wisdom of such a course and, likewise, in the matter before us leave broad discretion in the trial court to implement the details of comparative principles in strict products liability cases.

For the guidance of trial courts, we do note the existence, under rule 49(a), Federal Rules of Civil Procedure, of a form of special verdict tailored to cases applying the maritime doctrine of strict liability for unseaworthiness, to which we have referred. Under this form, the jury is first required to answer “yes” or “no” to a series of questions setting forth possible bases for a finding that vessel unseaworthiness was a proximate cause of the plaintiff’s injuries. If the jury indicates that unseaworthiness was a contributing cause, it then moves on to a second group of similar questions seeking to determine whether, and in what particulars, the plaintiff’s own negligence was also a contributing factor. If the answers to these questions establish a finding of contributory negligence, the jury is told to “state in percentage the extent to which the plaintiff’s own negligence contributed to his injuries. (_%).” Finally, the juiy is instructed to indicate the amount of plaintiff’s damages without reference to his own negligence. The court then reduces the damage award by the percentage figure the jury has supplied. (3 Devitt & Blackmar, Federal Jury Practice and Instructions (3d ed. 1977) § 96.32; see also Menard v. Penrod Drilling Co. (5th Cir. 1976) 538 F.2d 1084, 1086-1087.) We cite this form as illustrative of one technique by which the court and jury may approach the task of apportionment.

Retroactivity

It remains for us to decide the extent to which comparative principles are to be applied to strict liability actions other than those hereafter filed. We conclude that, for reasons of public policy and the reasonable expectations of the parties to this action and litigants generally, the principles herein expressed shall apply to all cases in which trial has not begun before the date this opinion becojmes final in this court. No judgment based upon a trial which was commenced prior to the finality of this opinion shall be reversible on appeal on the sole ground that principles of comparative fault were not applied. If any such *744judgment is reversed on appeal for other reasons, the principles herein expressed shall be applicable to any retrial commenced after this opinion becomes final in this court. (Li v. Yellow Cab Co., supra, 13 Cal.3d at p. 829; Westbrook v. Mihaly (1970) 2 Cal.3d 765, 800 [87 Cal.Rptr. 839, 471 P.2d 487], vacated on other grounds (1971) 403 U.S. 915 [29 L.Ed.2d 692, 91 S.Ct. 2224].) As in Li, we give particular emphasis to “considerations of reliance applicable to individual cases according to the stage of litigation which they have reached ....” (Ibid.)

While it is arguable that retroactivity should extend to the finality of Li, and it is true that our conclusions herein owe a distinct philosophical debt to that case, nonetheless they do not constitute a direct application of Li. Furthermore, in Horn v. General Motors Corp. (1976) 17 Cal.3d 359, 370 [131 Cal.Rptr. 78, 551 P.2d 398], decided subsequent to Li, we retained, if only briefly, the separate system of defenses applicable to strict products liability. Under the circumstances before us, we conclude that it would be manifestly unfair to make the present opinion effective as of the finality of Li.

We further conclude that, under the particular circumstances, comparative principles cannot be applied retroactively to the instant case in order to justify admission of the intoxication and “nonuse” evidence here challenged. The issue of comparative fault was raised for the first time on appeal, and was never placed in issue by any party at trial herein. No jury instructions on the issue were requested or given. The juiy therefore had no basis for evaluating the evidence under correct principles of comparative fault. In the event of retrial, however, the principles herein announced will, of course, apply.

We turn to an explanation of the reasons which prompt us to reverse the judgment of the trial court, and then examine, for the benefit of court and counsel one of the remaining contentions of the parties.

The Safety Equipment And Intoxication Evidence

We must determine whether admission of evidence of decedent’s failure to use available safety devices and of his intoxication constituted prejudicial error under rules heretofore applicable to strict liability cases. We conclude that it did.

*745While initially evidence bearing on decedent’s intoxication was excluded, other evidence pertaining to the decedent’s alleged failure to employ seat belts and door locks was admitted, apparently on the ground that nonuse of safety devices bore on the issues of proximate cause and mitigation of damages. Plaintiffs contended that evidence of Daly’s intoxication, or of his failure to use available safety devices, was wholly inadmissible since contributory negligence was not a defense to an action founded in strict liability for a defective product. (Horn v. General Motors Corp., supra, 17 Cal.3d at pp. 369-371; Luque v. McLean, supra, 8 Cal.3d 136, 145.) The trial court ultimately admitted the intoxication evidence, ruling that such evidence related to decedent’s failure to use the Opel’s safety devices, which failure, the court reasoned, would bar recovery on the theory of product misuse “aside from any question of contributory negligence.” (In fairness to the very able trial judge, it must be noted that the trial herein preceded rendition of our opinions in both Li and Horn.)

As we observed in Horn, to accept a “nonuse” of safety equipment as a complete defense to a products liability action would constitute but a thinly disguised subversion of the rule that contributory negligence does not prevent recovery. Horn expressly rejected arguments that such “nonuse” could defeat recovery on theories of “assumption of risk,” “product misuse,” “proximate cause,” or “mitigation of damages.” (Id., at pp. 369-371.)

Substantial time was spent on the nonuse and intoxication issues, reasonably suggesting to tíre jury their central importance to the defense case. There can be little doubt that the evidence of Daly’s intoxication was inflammatory. The only restrictions placed on the jury’s consideration of the intoxication evidence was that it bore on the “nonuse” of safety devices in general. No limitation was placed on the conclusions which the jury could draw either from a finding of “nonuse” itself, or as to the effect on its deliberations of a finding of “nonuse.” In the absence of any such restrictions, we think the jury could well have concluded that decedent’s negligent failure, induced by intoxication, to use the belts and locks constituted negligent conduct which completely barred recovery for his death. We do not think it reasonable to conclude that plaintiffs waived their objection by failing to request limiting instructions.

In summary, our review of the record convinces us that, notwithstanding that plaintiffs’ case was founded on strict products liability, evidence of decedent’s failure to use available seat belts and door locks, and of his *746intoxication at the time of the fatal collision, may have been improperly regarded by the jury as authorizing a defense verdict. It appears reasonably probable that, had such evidence been either excluded or its effect confined, a result more favorable to plaintiffs would have been reached. Reversal is therefore required. (People v. Watson (1956) 46 Cal.2d 818, 836 [299 P.2d 243]; Downing v. Barrett Mobile Home Transport, Inc. (1974) 38 Cal.App.3d 519, 525 [113 Cal.Rptr. 277]; see Henderson v. Harnischfeger Corp. (1974) 12 Cal.3d 663, 670-676 [117 Cal.Rptr. 1, 527 P.2d 353].)

Defect—Component Or Product As A Whole?

We examine for the benefit of court and counsel, in the event of retrial, a single remaining contention of plaintiffs.

Plaintiffs challenge a jury instruction which directed that “[i]n determining whether or not the vehicle was defective you should consider all of the equipment on the vehicle including any features intended for the safety of the driver.” They urge that only the precise malfunctioning component itself, and alone, may be considered in determining whether injury was caused by a defectively designed product. We disagree, concluding that the issue of defective design is to be determined with respect to the product as a whole, and that the trial court’s instruction was correct.

The jury could properly determine whether the Opel’s overall design, including safety features provided in the vehicle, made it “crashworthy,” thus rendering the vehicle nondefective. Product designs do not evolve in a vacuum, but must reflect the realities of the market place, kitchen, highway, and shop. Similarly, a product’s components are not developed in isolation, but as part of an integrated and interrelated whole. Recognizing that finished products must incorporate and balance safety, utility, competitive merit, and practicality under a multitude of intended and foreseeable uses, courts have struggled to evolve realistic tests for defective design which give weight to this necessary balancing. Thus, a number of California cases have recognized the need to “weigh” competing considerations in an overall product design, in order to determine whether the design was “defective.” Recently, we ourselves in Barker v. Lull (1978) ante, pp. 413, 431 [143 Cal.Rptr. 225, 573 P.2d 443], have described some of the factors to be considered. (See, also, Buccery v. General Motors Corp. (1976) 60 Cal.App.3d 533, 547 [132 Cal.Rptr. 605]; Baker v. Chrysler Corp. (1976) 55 Cal.App.3d 710, 716 [127 Cal.Rptr. 745]; Hyman v. Gordon (1973) 35 Cal.App.3d 769, 773 [111 Cal.Rptr. 262].)

*747The danger of piecemeal consideration of isolated components has been expressly recognized. (Self v. General Motors Corp. (1974) 42 Cal.App.3d 1, 6-7 [116 Cal.Rptr. 575]; Dreisonstok v. Volkswagenwerk A.G. (4th Cir. 1974) 489 F.2d 1066, 1071-1072, applying Virginia law.) Specifically, it has been observed that a design rendered safe in one situation may become more dangerous in others. (Self supra, at pp. 6-7.) However phrased, these decisions emphasize the need to consider the product as an integrated whole.

We find that plaintiffs’ other contentions lack merit.

Conclusion

It is readily apparent that the foregoing broad expressions of principle do not establish the duties of the jury with that fixed precision which appeals to minds trained in law and logic. Nonetheless, rather than attempt to anticipate every variant and nuance of circumstance and party that may invoke comparative principles in a strict products liability context, we deem it wiser to await a case-by-case evolution in the application of the broad principles herein expressed.

By extending and tailoring the comparative principles announced in Li, supra, to the doctrine of strict products liability, we believe that we move closer to the goal of the equitable allocation of legal responsibility for personal injuries. We do so by relying on what Professor Schwartz aptly terms a “predicate of fairness.” In making liability more commensurate with fault we undermine neither the theories nor the policies of the strict liability rule. In Li we took “a first step in what we deem to be a proper and just direction, . . .” (13 Cal.3d at p. 826.) We are convinced that the principles herein announced constitute the next appropriate and logical step in the same direction.

The judgment is reversed.

Tobriner, J., Clark, J., and Manuel, J., concurred.

CLARK, J.

The reasoning of Li v. Yellow Cab Co. (1975) 13 Cal.3d 804 [119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393], as the majority point out, is equally applicable to strict liability cases and compels applying *748comparative fault in those cases. (Horn v. General Motors Corp. (1976) 17 Cal.3d 359, 372 [131 Cal.Rptr. 78, 551 P.2d 398] (dis. opn. of Clark, J.).) Under the compulsion of Li, I have signed the majority opinion.

Nevertheless, again we must recognize the difficulties inherent in comparing fault. (See American Motorcycle Assn. v. Superior Court (1978) ante, pp. 578, 608 [146 Cal.Rptr. 182, 578 P.2d 899] (dis. opn. of Clark, J.).) Relying on the apples and oranges argument, Justices Mosk and Jefferson point out that comparative fault cannot be applied logically and consistently in strict liability cases. (Infra, pp. 762-764, 751 et seq.) The difficulty, however, isnotlimitedto comparingstrictliabilitywith negligence. The same difficulty persists in almost every case in which we attempt to compare parties’ negligence. (Horn v. General Motors Corp., supra, 17 Cal.3d 359, 377 (dis. opn.).)

For example, assume three drivers collide at an intersection, one being intoxicated, the second speeding, and the third having gone through a stop signal. Neither logic nor common experience can tell us how much of the loss is attributable to each driver. Logic cannot tell us that the first should bear 10 percent of the loss, the second 30, and the third 60.1 Nor may it establish any other percentages of liability. When we substitute a defective product for one of the drivers’ negligence, we neither add to nor subtract from the difficulty of the comparison, and the problem of comparison is the same whether we compare different negligent acts or compare a negligent act to a defect.

Logic failing, is there a hope that juries, or judges when juries are waived, will arrive at consistent results? Obviously not.2 It is not a problem that the allocation of fault cannot be precisely measured —rather, in most cases there is no measuring standard.

The lack of logic and consistency not only means that most claims will not be disposed of equitably but also that attorneys may seldom reasonably evaluate the cases for purposes of settlement. And because settlement plays such a large part in the determination of accident claims the efficient administration of justice is substantially impaired.

*749I also must part company from Justices Mosk and Jefferson as to the effect of the apples and oranges argument. The difficulty in comparing fault does not warrant either returning to the all-or-nothing rule applicable to contributory negligence cases prior to Li or continuing the all-or-nothing rule applied in strict liability cases. Dean Prosser’s famous statement remains unanswerable. It is improper to place “upon one party the entire burden of a loss for which two are, by hypothesis, responsible.” (Prosser, Torts (4th ed. 1971) § 67, p. 433.) The statement is as applicable to negligence cases as it is to strict liability cases. Apples and oranges do not warrant denial of loss apportionment—they require establishing a better system of apportionment.

Li effectively pointed out that the existing contributory negligence system placed on one party the entire burden of a loss for which two were responsible (13 Cal.3d at p. 810, fn. 3), and today’s majority opinion effectively points out that the negligent plaintiff is responsible and should not recover as much as an innocent one. (Ante, pp. 736-737.)

Those principles do not require a comparative fault system. Can they not be satisfied by a system which establishes a uniform index factor, such as 30, 50 or 70 percent? A uniform discount of the negligent plaintiff’s recovery would eliminate the necessity of the often impossible task of comparing fault. A discount system would bring about consistency and predictability where neither now exists, permitting evaluation and settlement of claims.

Such an approach is consistent with the departure from the Li principle made by the majority in American Motorcycle Assn. v. Superior Court, supra, ante, page 578, and in the instant case. In Li, this court repeatedly emphasized that the extent of fault should govern the extent of “liability” (e.g., 13 Cal.3d at pp. 811, 813, 829). By repeated use of the word “liability” rather than recovery the emphasis was placed on fairness to the defendant in the new comparative fault doctrine, and throughout the opinion comparability of fault is emphasized. However, a selective rejection of the Li reasoning appears in American Motorcycle in connection with the discussion of joint and several liability. The faimess-to-defendant justification for comparative fault is ignored, rather the court relies upon a policy of compensating injured plaintiffs. (Ante, p. 578.) And the court suggests that there is a significant difference between plaintiff negligence—a failure to exercise due care for oneself —and defendant negligence—a failure to exercise due care for others. (Ante, p. 578.) Today’s opinion, telling us that “the ‘apples and oranges’ *750argument may be conceptually suspect,” similarly emphasizes the difference between plaintiff and defendant fault, pointing out the difficulty in finding a breach of duty upon which to predicate plaintiff negligence. (Ante, pp. 735-736.)

In cases where the plaintiff is not negligent, the determination of liability is based on fault, and the extent of liability is based solely on amount of loss—whether grossly or marginally negligent, the defendant’s liability is the same. By focusing on a policy of compensating injured plaintiffs, pointing out the difference between plaintiff and defendant negligence, and providing that plaintiff’s recovery is to be diminished on the basis of his fault without regard to defense fairness, this court has departed from the Li principle, reflecting recognition of its shortcomings. We also should recognize that comparative fault—although equitable in theory—cannot be applied equitably, and precludes consistency of result, making settlement much more difficult and substantially impairing the efficient administration of justice.

We can and should do a better job. A discount system will not eliminate all inequities. Arbitrary results are inherent in attempting to adjust a loss between the two or more parties responsible, when their fault is based on different acts. The present comparative system is not only inequitable and arbitrary but also inconsistent and unpredictable. Eliminating two of the four defects by adoption of a discount system is worthy of the court’s task.

Having úndertaken the legislative function by repudiating contributory negligence and adopting comparative fault, we have abandoned our traditional deference to legislative province and to stare decisis. Having done so, we, like the Legislature, should reconsider our bold decisions from time to time, performing the legislative process to the best of our ability—until the Legislature awakens to reclaim and exercise its historic power.

JEFFERSON, J.*

I concur in part and dissent in part.

I agree with the majority’s result that the judgment should be reversed because of the prejudicial error in admitting evidence of decedent’s *751intoxication and of his failure to use available safety devices. Otherwise, I part company with the majority’s views.

The majority takes the position that, since Li v. Yellow Cab Co. (1975) 13 Cal.3d 804 [119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393], adopted the doctrine of comparative negligence in tort actions founded on negligence, principles of justice, fairness and equity dictate an extension of comparative principles to tort actions founded on strict liability, introduced in Greenman v. Yuba Power Products, Inc. (1963) 59 Cal.2d 57 [27 Cal.Rptr. 697, 377 P.2d 897, 13 A.L.R.3d 1049]. The majority, however, does not consider it significant that it is unable to determine what labels should be given to the new comparative principles—whether the new doctrine should be known as comparative fault, equitable apportionment of loss, or equitable allocation of loss. This inability to give the new doctrine an appropriate label is some indication of the shaky ground upon which the majority has decided to tread.

The majority rejects what I consider to be a sound criticism of its holding—that it is illogical and illusory to compare elements or factors that are not reasonably subject to comparison. The majority states that it is convinced that jurors will be able to compare the noncomparables— plaintiff’s negligence with defendant’s strict liability for a defective product—and still reach a fair apportionment of liability.

I consider the majority conclusion a case of wishful thinking and an application of an impractical, ivory-tower approach. The majority’s assumption that a jury is capable of making a fair apportionment between a plaintiff’s negligent conduct and a defendant’s defective product is no more logical or convincing than if a jury were to be instructed that it should add a quart of milk (representing plaintiff’s negligence) and a metal bar three feet in length (representing defendant’s strict liability for a defective product), and that the two added together equal 100 percent—the total fault for plaintiff’s injuries; that plaintiff’s quart of milk is then to be assigned its percentage of the 100 percent total and defendant’s metal bar is to be assigned the remaining percentage of the total. Either the jury or the trial judge will then subtract from the total amount of plaintiff’s damages an amount equal to the percentage of total fault allocated to plaintiff.

What the majority envisions as a fair apportionment of liability to be undertaken by the jury will constitute nothing more than an unfair reduction in the plaintiff’s total damages suffered, resulting from a jury *752process that necessarily is predicated on speculation, conjecture and guesswork. Because the legal concept of negligence is so utterly different from the legal concept of a product defective by reason of manufacture or design, a plaintiff’s negligence is no more capable of being rationally compared with a defendant’s defective product to determine what percentage each contributes to plaintiff’s total damages than is the quart of milk with the metal bar—posed in the above illustration.

The majority sets forth an example of how a trial judge might instruct a juiy, borrowing from a form, of special verdict, set forth under rule 49(a), Federal Rules of Civil Procedure, and tailored to the maritime doctrine of strict liability for unseaworthiness. The suggested instruction only emphasizes the futility in seeking to find logic and fairness in comparing noncomparables. The suggested instruction does nothing more than tell the juiy to do what I have posed heretofore, namely, to consider that a quart of milk and a metal bar equal 100 percent of fault and then decide what percentage of 100 percent is represented by each item.

There is simply no reasonable or logical formula or standard that can be given to the juiy to guide it in considering a defendant’s defective product and a plaintiff’s negligence as constituting 100 percent of fault for plaintiff’s injuries and then deciding what percentage of this 100 percent is caused by each of the two noncomparables—plaintiff’s negligence on the one hand and defendant’s defective product on the other. There is no doubt that q juiy, when so instructed, can, and will, assess a plaintiff’s negligence at some percentage between zero and 100 percent.. But the percentage assessed will represent nothing more substantial or reasonable than that which results from the application of the jurors’ instincts, speculations, conjectures and guesses.

I am persuaded that the juiy’s task under the majority’s holding does not, and cannot, produce justice, equity, or any fair apportionment of fault or loss. The defendant’s liability for a defective product placed in the stream of commerce should not be subject to diminution and dilution by the speculative verdict of a juiy in diminishing a plaintiff’s recoveiy of the total damages suffered from a defective product, pursuant to a trial judge’s instruction that noncomparable factors must be compared to reduce the plaintiff’s recovery from the total damages he has suffered to something less than the total.

*753A consideration of the instructions likely to be given to the jury under the majority’s holding will reveal the merit and substantiality of the objections to the majority’s views. Thus, a jury may, or may not, receive an instruction defining a “defect” in a product or a “defective” product. (See Barker v. Lull Engineering Co. (1978) ante, p. 413 [143 Cal.Rptr. 225, 573 P.2d 443].) The definition of negligence, usually given to a jury, is found in BAJI instruction No. 3.10.1 We can assume that, in substance, the jury will be told that if it finds that defendant’s product was defective in manufacture or design and that such defective product was a proximate cause of plaintiff’s injuries, and that if it also finds that plaintiff was negligent and that such negligence was also a proximate cause of plaintiff’s injuries, the two factors are to be considered as constituting 100 percent of fault (assuming there are no other proximate causes) for plaintiff’s injuries. The jury will then be told to determine what percentage each of these factors contributes to reach the 100 percent total.

Again, an instruction to the jury might be in the form of a revision of BAJI instruction No. 3.50 (1975 rev.),2 reading in essence as follows: “Contributory fault is negligence on the part of plaintiff which, combined with the defective product of defendant, contributes as a proximate cause in bringing about the injury. Contributory fault, if any, on the part of the plaintiff, does not bar a recovery by the plaintiff against the defendant but the total amount of plaintiff’s damages to which he would otherwise be entitled by reason of the injuries suffered from defendant’s defective product shall be reduced in proportion to the *754amount of fault—represented by his negligence—that is attributed to him, contrasted with the percentage of fault—represented by defendant’s defective product—that is attributable to defendant.”

But the missing element in this equation is the fact that there is no formula, no standard—other than what may be concocted in the jurors’ minds—to guide the jury in equating plaintiff’s negligence with defendant’s defective product to make the two equal 100 percent of fault and determine the respective contributions as a definitive percentage of this total fault.

This court had occasion recently to set forth a two-pronged test for determining the existence of a product made defective by virtue of its design. The court held that a product is “defective in design either (1) if the product has failed to perform as safely as an ordinary consumer would expect when used in an intended or reasonably foreseeable manner, or (2) if, in light of [certain] relevant factors . . ., the benefits of the challenged design do not outweigh the risk of danger inherent in such design.” (Barker, supra, ante, pp. 413,418.) The Barker court then made the cogent observation that “this test reflects our continued adherence to the principle that, in a product liability action, the trier of fact must focus on the product, not on the manufacturer’s conduct, and that the plaintiff need not prove that the manufacturer acted unreasonably or negligently in order to prevail in such an action.” (Ibid.) (Italics in original.)

The majority’s decision herein will require the jury, on the one hand, to follow Barker and focus on the manufacturer’s product—disregarding all questions of whether the manufacturer acted unreasonably or negligently—in order to determine defendant manufacturer’s liability. On the other hand, the juiy must next focus on plaintiff’s conduct, in order to find that plaintiff was negligent. The jury must then compare its focus on plaintiff’s negligent conduct with its focus on defendant’s defective product—eliminating, as irrelevant, any consideration of whether defendant’s conduct was unreasonable or negligent—to determine the amount of the reduction in plaintiff’s total damages. The end result of this configurational analysis by a jury, I submit, based as it must be—on a comparison of noncomparables—will necessarily constitute a patently unfair result.

Juries have been uniformly instructed over the years that they are “not permitted to award a party speculative damages, which means compensation for future loss or harm which, although possible, is conjectural or *755not reasonably certain.” (See BAJI No. 14.60 (1977 rev.).) But the majority’s holding today will require juries to reduce a party’s “reasonably certain” damages by using speculation, conjecture or occult divination and thus produce a verdict for damages that is the very antithesis of the principle enunciated by BAJI No. 14.60—an instrument which will continue to be given to juries in personal injury cases.

The guessing game that will be imposed on juries by the application of comparative negligence principles to defective product liability cases will be further enhanced in those cases in which several defendants are joined in an action—some being sued on a negligence theory and others on the defective product theory and where there are several plaintiffs whose conduct may range from no negligence at all to varying degrees of negligence. The jury will be required to determine percentages of fault with respect to all the parties (and perhaps some nonparties) by seeking to compare and evaluate the conduct of certain parties with the product of other parties to produce 100 percent of fault as the necessary starting point in order to calculate a reduction in the damages suffered by each plaintiff found to be negligent. I cannot agree with the majority that such a process is reasonably workable or that it will produce an equitable result to injured plaintiffs. If a just or fair result is reached by a jury under the majority’s holding, it will be strictly accidental and accomplished by pure happenstance.

With all due deference to the scholarly analysis and discussion found in the majority opinion, I must conclude, nevertheless, that the majority’s view constitutes a glaring failure to appreciate the limitations on, and the realities of, our jury trial system. Under the majority’s view, jurors are expected to accomplish a feat which trained judges cannot accomplish, namely, to reach a just result by starting with an untenable premise that totally different things—a plaintiff’s negligent conduct and a defendant’s defective product—can be added together and assigned percentages to total 100 percent, without having the means to reduce the two noncom-parables to a common denominator which is the necessary ingredient to produce reasonably accurate percentages. There is no common denominator by which factors such as pounds, circles, quarts, triangles, inches, and squares can be added together for a total so that a determination can be made of the percentage contribution of each to the total. This is the situation we deal with in requiring juries to reduce a plaintiff’s total damages resulting from a defendant’s defective product by a conjectural determination of a percentage contribution to thosé damages resulting from plaintiff’s negligence.

*756The majority finds significance in the provisions of the proposed Uniform Comparative Fault Act (Act), authored by Professor Wade, “a recognized torts scholar” and a “distinguished professor of law.” The proposed Act adopts the principles of comparative fault. It defines “fault” to include acts or omissions that constitute negligence or that subject a person to strict tort liability. The proposed Act requires a reduction in a plaintiff’s recovery based upon plaintiff’s proportionate contributory fault. But with all due respect to the high academic qualifications of the author, the Act possesses the same weaknesses that I find in the majority’s assumptions. The Act does not produce a practical formula, or any formula at all, by which the jury can avoid the task of employing conjecture, surmise and speculation in seeking to compare noncomparable factors that make up the Act’s concept of total “fault.” The Act’s provisions, therefore, suffering from the same weaknesses that permeate the majority’s holding, offer no support in logic, reason or fairness to the majority’s holding.

The majority calls attention to the fact that some legal scholars and some states have either moved, or have advocated moving, in the direction of the application of comparative negligence principles to strict-liability-in-tort cases. Such authorities do not demonstrate that the principle espoused is a viable one. The fact that some legal scholars and states are satisfied with a tort principle that requires and sanctions speculation and guesswork on the part of juries—necessarily producing inequities to consumers who have suffered injuries from manufacturers’ defective products—constitutes no basis for this court to follow suit.

It is my view that justice, fairness and equity are not served by the majority’s application of the Li principle of comparative negligence to the tort principle of a manufacturer’s strict liability in tort for a product defectively manufactured or defectively designed. Granting that a plaintiff was negligent when he suffered injury from using a defective product, a fair and equitable result is reached by imposing on the defendant manufacturer liability for the total damages suffered. This result is preferable to that of subjecting the injured plaintiff’s claim to a diminution of his total damages suffered—predicated on the jury’s application of the highly speculative, conjectural and chance formula of comparing two noncomparables.

It appeals to my sense of reason, justice and equity that we continue the existing legal principle which permits manufacturers to spread through society the costs of compensating injured plaintiffs fully, rather *757than the adoption of an untenable legal principle which will result in reducing the total costs to be spread by manufacturers, but at the expense of injured plaintiffs by reducing their recovery below the full losses sustained through the necessarily fortuitous, conjectural and haphazard determinations to be made by juries.

Bird, C. J., concurred.

MOSK, J.

I dissent.

This will be remembered as the dark day when this court, which heroically took the lead in originating the doctrine of products liability (Greenman v. Yuba Power Products, Inc. (1963) 59 Cal.2d 57 [27 Cal.Rptr. 697, 377 P.2d 897, 13 A.L.R.3d 1049]) and steadfastly resisted efforts to inject concepts of negligence into the newly designed tort (Cronin v. J. B. E. Olson Corp. (1972) 8 Cal.3d 121 [104 Cal.Rptr. 433, 501 P.2d 1153]), inexplicably turned 180 degrees and beat a hasty retreat almost back to square one. The pure concept of products liability so pridefully fashioned and nurtured by this court for the past decade and a half is reduced to a shambles.

The majority inject a foreign object—the tort of negligence—into the tort of products liability by the simple expedient of calling negligence something else: on some pages their opinion speaks of “comparative fault,” on others reference is to “comparative principles,” and elsewhere the term “equitable apportionment” is employed, although this is clearly not a proceeding in equity. But a rose is a rose and negligence is negligence; thus the majority find that despite semantic camouflage they must rely on Li v. Yellow Cab Co. (1975) 13 Cal.3d 804 [119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393], even though Li is purely and simply a negligence case which merely rejects contributory negligence and substitutes therefor comparative negligence.

Professor Schwartz made this acute observation (Schwartz, Li v. Yellow Cab Company: A Survey of California Practice Under Comparative Negligence (1976) 7 Pacific L. J. 747, 756): “The Li opinion, which was concerned with a typical automobile negligence case, contained no discussion of strict liability. In its April 24th modification of the opinion, the court in a number of places deleted the word ‘fault’ and substituted *758the word ‘negligence,’ perhaps indicating that it did not intend for its holding to apply to strict liability. Further, in a footnote of the modified opinion the court stated that ‘[i]n employing the generic term “fault” throughout this opinion we follow a usage common to the literature on the subject of comparative negligence. In all cases, however, we intend the term to import nothing more than “negligence” in the accepted legal sense.’ ”

What Professor Schwartz sensed was factually accurate. We desired, in Li, to affect only the concept of contributory negligence, and to substitute therefor the doctrine of comparative negligence. Where contributoiy negligence would have previously been relevant, comparative negligence was to be its replacement. It was never contemplated that comparative negligence would be injected into litigation in which contributoiy negligence had been specifically barred as a valid defense.

This court has emphasized over and over again that strict products liability is an independent tort species wholly distinct from contract warranties (Greenman v. Yuba Power Products, Inc., supra, 59 Cal.2d at p. 63) and from negligence (Cronin v. J. B. E. Olson Corp., supra, 8 Cal.3d at p. 133). Indeed, in Cronin we stressed that “the very purpose of our pioneering efforts in this field was to relieve the plaintiff from problems of proof inherent in pursuing negligence” (id.). 1 And in Luque v. McLean (1972) 8 Cal.3d 136 [104 Cal.Rptr. 443, 501 P.2d 1163], this court unanimously declared that “contributory negligence does not bar recoveiy in a strict liability action” (id. at p. 145). To the same effect are Bill Loeper Ford v. Hites (1975) 47 Cal.App.3d 828, 835-836 [121 Cal.Rptr. 131], and McGoldrick v. Porter-Cable Tools (1973) 34 Cal.App.3d 885, 889 [110 Cal.Rptr. 481],

The bench and bar have abided by this elementary rule. They have learned to avoid injecting negligence—whether of the defendant or the plaintiff—into a products liability case. And they have understood the reason behind the distinction between negligence of any party and products liability. It was expressed over three decades ago by Justice *759Traynor in his concurring opinion in Escola v. Coca Cola Bottling Co. (1944) 24 Cal.2d 453, 467 [150 P.2d 436]: “As handicrafts have been replaced by mass production with its great markets and transportation facilities, the close relationship between the producer and consumer of a product has been altered. Manufacturing processes, frequently valuable secrets, are ordinarily either inaccessible to or beyond the ken . of the general public. The consumer no longer has means or skill enough to investigate for himself the soundness of a product, even when it is not contained in a sealed package, and his erstwhile vigilance has been lulled by the steady efforts of manufacturers to build up confidence by advertising and marketing devices such as trade-marks. [Citations.] Consumers no longer approach products warily but accept them on faith, relying on the reputation of the manufacturer or the trade mark.... The manufacturer’s obligation to the consumer must keep pace with the changing relationship between them; . . .” And again in Greenman, Justice Traynor declared the “purpose of such liability is to insure that the costs of injuries resulting from defective products are borne by the manufacturers that put such products on the market rather than by the injured persons who are powerless to protect themselves.” (59 Cal.2d at p. 63.)

In Price v. Shell Oil Co. (1970) 2 Cal.3d 245, 258 [85 Cal.Rptr. 178, 466 P.2d 722], this court warned that “it would do violence to the doctrine of strict liability and thwart its basic purpose, if we were to interpret [an indemnity] clause as transferring the liability for a defective article from the party putting the article in the stream of commerce, to the user or consumer of the article who is within the class the doctrine was designed to protect.”

Transferring the liability, or part of the liability, from the party responsible for putting the article in the stream of commerce to the consumer is precisely what the majority propose to do. They do this by employing a euphemism: the victim’s recovery is to be “proportionately reduced.” The result, however delicately described, is to dilute the defect of the article by elevating the conduct of the wounded consumer to an issue of equal significance. We can be as certain as tomorrow’s daylight that every defendant charged with marketing a defective product will hereafter assert that the injured plaintiff did something, anything, that conceivably could be deemed contributorily negligent: he drove the vehicle with a defective steering mechanism 56 miles an hour instead of 54; or he should have discovered a latent defect hidden in the machinery; or perhaps he should not have succumbed to the salesman’s *760persuasion and purchased the defective object in the first instance. I need no crystal ball to foresee that the pleading of affirmative defenses alleging contributory negligence—or the currently approved substitute terminology—will now become boilerplate.

. The majority see no problem in assessing the liability of intermediate entities in the commercial chain. I do. Consider, for example, the not uncommon situation in which, pursuant to a faulty design, a manufacturer produces widgets without negligence and precisely as designed. He turns the widgets over to a distributor who sells them to a wholesaler who in turn consigns them to a retailer, none of whom commits any active act of negligence. After a defective widget finally reaches and injures the consumer, it would be consummate supererogation for a trier of fact to attempt to measure some consumer negligence against either the faulty design of the product or the responsibility of the congeries of nonnegligent persons who placed the defective product in the stream of commerce, or their responsibility vis-a-vis each other. We have retained joint and several liability in comparative negligence (American Motorcycle Assn. v. Superior Court (1978) ante, p. 578 [146 Cal.Rptr. 182, 578 P.2d 899]) partly because of that very problem. In any event if the consumer used the product as intended or as foreseeable (Barker v. Lull Engineering Co. (1978) ante, p. 413 [143 Cal.Rptr. 225, 573 P.2d 443]) it is inconsequential that he committed some extraneous act of negligence, since the injury occurs whether or not there was an act of omission or commission by the user; it results from the commercial exploitation of a defective product.

The defective product is comparable to a time bomb ready to explode; it maims its victims indiscriminately, the righteous and the evil, the careful and the careless. Thus when a faulty design or otherwise defective product is involved, the litigation should not be diverted to consideration of the negligence of the plaintiff. The liability issues are simple: was the product or its design faulty, did the defendant inject the defective product into the stream of commerce, and did the defect cause the injury? The conduct of the ultimate consumer-victim who used the product in the contemplated or foreseeable manner is wholly irrelevant to those issues.

The majority devote considerable effort to rationalizing what has been described as a mixture of apples and oranges. Their point might be persuasive if there were some authority recognizing a defense of contributory products liability, for which they are now substituting *761comparative products liability. However, all our research to discover such apples and oranges has been fruitless. The conclusion is inescapable that the majority, in avoiding approval of comparative negligence in name as a defense to products liability, are thereby originating a new defense that can only be described as comparative products liability. We may now anticipate similar defenses in the vast number of other tort actions. Can comparative libel, comparative slander of title, comparative wrongful litigation, comparative nuisance, comparative fraud, be far behind? By whatever name, negligence, heretofore just one subtopic in the elaborate spectrum of torts—which require six volumes and appendices of the Restatement Second of Torts to cover—now seems destined to envelop the entire tort field.

Reliance by the majority upon federal maritime cases is to a certain extent misleading and at best unpersuasive. Pope & Talbot, Inc. v. Hawn (1953) 346 U.S. 406 [98 L.Ed. 143, 74 S.Ct. 202], which considered the plaintiff’s negligence to “mitigate, but not bar, recovery,” involved a carpenter, not a seaman, who was working on board a ship in dock, and who sued the shipowners for negligence in maintaining an unseaworthy vessel. No novel theory of law was involved in weighing the negligence of the plaintiff against the negligence of the defendant. None of the other Supreme Court cases cited by the majority (The Osceola (1903) 189 U.S. 158 [47 L.Ed. 760, 23 S.Ct. 483]; Mitchell v. Trawler Racer, Inc. (1960) 362 U.S. 539 [4 L.Ed.2d 941, 80 S.Ct. 926]; Seas Shipping Co. v. Sieracki (1946) 328 U.S. 85 [90 L.Ed. 1099, 66 S.Ct. 872]) mention the doctrine of comparative negligence.

Conceding, nevertheless, that federal courts today are likely to apply comparative negligence in maritime cases, I find there is a sound rationale for treating the law of the sea differently from common law tort litigation. Justice Stone articulated the Supreme Court’s theory in Socony-Vacuum Co. v. Smith (1939) 305 U.S. 424 [83 L.Ed. 265, 59 S.Ct. 262], He observed that a seaman, while on a vessel abroad or on the high seas “is subject to the rigorous discipline of the sea and has little opportunity to appeal to the protection from abuse of power which the law makes readily available to the landsman.. . . Withal, seamen are the wards of the admiralty, whose traditional policy has been to avoid, within reasonable limits, the application of rules of the common law____” (Id., at pp. 430-431 [83 L.Ed. at p. 270].) In short, admiralty is recognized as a unique field of law, generally uninfluenced by the common law, and thus it is improvidently cited for the purpose of influencing the common law.

*762The best reasoned authorities decline to inject negligence, contributory or comparative, into strict products liability litigation. In Kirkland v. General Motors Corporation (Okla. 1974) 521 P.2d 1353, the Oklahoma Supreme Court refused to apply a comparative negligence statute to products liability because it consistently determined that “manufacturers’ products liability is not negligence, nor is it to be treated as a negligence action” (id. at p. 1367). A similar result followed in Melia v. Ford Motor Co. (8th Cir. 1976) 534 F.2d 795, 802, in which the court held application of a comparative negligence statute would be “inappropriate in a strict liability case.” Even more emphatic was the court in Kinard v. Coats Co., Inc. (1976) — Colo.App. — [553 P.2d 835, 837]: “Although some other jurisdictions have chosen to apply comparative negligence to products liability cases [citation] in our view the better-reasoned position is that comparative negligence has no application to products liability actions under § 402A. [If] Products liability under § 402A does not rest upon negligence principles, but rather is premised on the concept of enterprise liability for casting a defective product into the stream of commerce. [Citations.] Thus, the focus is upon the nature of the product, and the consumer’s reasonable expectations with regard to that product, rather than on the conduct either of the manufacturer or of the person injured because of the product. [Citations.]” The Colorado Supreme Court completely eliminated negligence from products liability actions, declaring in such proceedings it “ ‘shifts the focus from the conduct of the manufacturer to the nature of the product.’ ” (Hiigel v. General Motors Corporation (1975) — Colo. — [544 P.2d 983, 988].)

We also declared in Ault v. International Harvester Co. (1974) 13 Cal.3d 113 [117 Cal.Rptr. 812, 528 P.2d 1148, 74 A.L.R.3d 986], that the focus is not on the conduct of the defendant, but on the nature of the product. That being so, the majority create an impossible dilemma for trial courts. If comparative negligence is to be applied, how can the trier of fact rationally weigh the conduct of the plaintiff against the defective product? I know of no other instance in American jurisprudence in which the antagonists are the conduct of a human being versus an inanimate object.

Professor Levine discusses the Alaska case (Butaud v. Suburban Marine & Sport. Goods, Inc. (Alaska 1976) 555 P.2d 42) and others relied upon by the majority (Levine, Strict Products Liability and Comparative Negligence: The Collision of Fault and No-Fault (1977) 14 San Diego L.Rev. 337) and concludes that it is impossible to apply a comparison of fault doctrine—comparative negligence—to a no-fault *763doctrine—strict products liability: “In California, comparative fault cannot logically and consistently be applied to the strict liability cause of action. Prejudice to a plaintiff would result if the jury was required to determine the plaintiff’s fault and to compare it to the defendant’s conduct in a cause of action not requiring that a jury consider the existence, nature, or extent of defendant’s culpability. How can comparative fault exist in a cause of action which proceeds irrespective of fault? What can a jury compare the plaintiff’s fault with if the defendant’s fault is not at issue? If the jury has not determined the nature, extent, or degree of the defendant’s fault but has merely concluded the product is defective, how can it reduce the plaintiff’s damages in proportion to respective fault?

“The application of ‘comparative’ fault to the strict products liability cause of action would prejudice a plaintiff because of the unusual and impossible demand placed upon a jury. In essence we would ask a jury that if they find the defendant’s product was defective, irrespective of fault, they should reduce the plaintiff’s damage by considering the plaintiff’s culpability in proportion to the defendant’s non-culpability. This requirement may be a feat which is beyond the prowess of an American jury.” (Id. at p. 356; italics omitted.)

The Court of Appeal reached the same conclusion in Buccery v. General Motors Corp. (1976) 60 Cal.App.3d 533, 549 [132 Cal.Rptr. 605]: “Comparative negligence, therefore, as adopted in Li, entails a comparison of the respective negligence of the plaintiff on the one hand and of the defendant on the other. Strict liability for defective products is not based upon defendant’s negligence. There may be, therefore, no negligence of the defendant to compare with that of plaintiff.”

The majority note one “felicitous result” of adopting comparative negligence to products liability: the merger of assumption of risk—which they term a “bizarre anomaly”—into their innovative defense. I find that result neither felicitous nor tenable. In Barker v. Lull Engineering Co., supra, ante, at page 429, we defined a defective product as one which failed to perform safely when used in an intended or foreseeable manner. If a consumer elects to use a product patently defective when other alternatives are available, or to use a product in a manner clearly not intended or foreseeable, he assumes the risks inherent in his improper utilization and should not be heard to complain about the condition of the object. One who employs a power saw to trim his fingernails—and thereafter finds the number of his fingers reduced— *764should not prevail to any extent whatever against the manufacturer even if the saw had a defective blade. I would retain assumption of risk as a total defense to products liability, as it always has been.

The majority deny their opinion diminishes the therapeutic effect of products liability upon producers of defective products. It seems self-evident that procedures which evaluate the injured consumer’s conduct in each instance, and thus eliminate or reduce the award against the producer or distributor of a defective product, are not designed as an effective incentive to maximum responsibility to consumers. The converse is more accurate: the motivation to avoid polluting the stream of commerce with defective products increases in direct relation to the size of potential damage awards.

In sum, I am convinced that since the negligence of the defendant is irrelevant in products liability cases, the negligence—call it contributory or comparative—of the plaintiff is also irrelevant. The majority, by considering the comparative negligence of a plaintiff in an action in which defendant’s negligence is not an issue, apply an untenable double standard. Their error is grievously unsettling to the law of torts. More significantly, this decision seriously erodes the pattern of the law which up to now reflected a healthy concern for consumers victimized by defective products placed on the market in this mechanized age through the dynamics of mass production, national and international distribution, and psychologically subtle marketing.

The length of the majority opinion and this opinion dissuades me from discussing the other issues involved herein. My abstention should not be construed as acquiescence in the majority’s conclusions. I see no reason to reverse the trial court.

I would affirm the judgment.

Appellants’ petition for a rehearing was denied April 13, 1978, and the opinion was modified to read as printed above. Bird, C. J., and Mosk, J., were of the opinion that the petition should be granted.