SANDERS, Justice.

This is a tort action. Plaintiff, the 67-year-old widow of Tanner Perkins, seeks damages for the death of her husband in the collision of an automobile, in which he was riding, with a train of the defendant railroad. The district court awarded damages. The Court of Appeal affirmed.1 We granted certiorari to review the judgment of the Court of Appeal.

The tragic accident which gave rise to this litigation occurred at the intersection of Eddy Street and The Texas and New Orleans Railroad Company track in the town of Vinton, Louisiana, at approximately 6:02 a. m., after daylight, on September 28, 1959. At this crossing Eddy Street runs north and south, and the railroad track, east and west. Involved was a 113-car freight train pulled by four diesel engines traveling east and a Dodge auto*647mobile driven by Joe Foreman in a southerly direction on Eddy Street. Tanner Perkins, a guest passenger, was riding in the front seat of the automobile with the driver.

Located in the northwest quadrant of the intersection of the railroad track and Eddy Street was a warehouse five hundred feet long. A “house track” paralleled the main track on the north to serve the warehouse. This warehouse obstructed the view to the west of an automobile driver approaching the railroad crossing from the north on Eddy Street. It likewise obstructed the view to the north of trainmen approaching the crossing from the west. Having previously served on this route, the engineer and brakeman were aware of this obstruction.

To warn the public of the approach of trains, the defendant railroad had installed at the crossing an automatic signal device consisting of a swinging red light and a bell. At the time of the accident, this signal was operating. A standard Louisiana railroad stop sign and an intersection stop sign were also located at the crossing.

Proceeding east, the train approached the intersection with its headlight burning, its bell ringing, and its whistle blowing.

The engineer, brakeman, and fireman were stationed in the forward engine of the train. The engineer was seated on the right or south side, where he was unable to observe an automobile approaching from the left of the engine. The brakeman and fireman, who were seated on the left or north side of the engine, were looking forward as the train approached the intersection. These two crewmen saw the automobile emerge from behind the warehouse. At that time the front wheels of the automobile were on or across the north rail of the house track. The fireman estimated that the train was approximately 60 feet from the crossing when the automobile emerged from behind the warehouse. The brakeman, however, estimated that the train was 30 to 40 feet from the crossing at the time the automobile came into view. Both crewmen immediately shouted a warning to the engineer, who applied the emergency brakes. The train struck the right side of the automobile and carried it approximately 1250 feet. The two occupants were inside the automobile when it came to rest. Both were killed.

The speed of the automobile in which Tanner Perkins was riding was variously estimated from 3-4 miles per hour to 20-25 miles per hour.

The plaintiff and defendant railroad concede in their pleadings that Joe Foreman, the driver of the automobile, was negligent in driving upon the track in front of the train and that his negligence was a proximate cause of the death of Tanner Perkins.2

It is conceded that the railroad’s safety regulations imposed a speed limit of 25 miles per hour on trains in the town of Vinton. The plaintiff has conceded in this Court that this self-imposed speed limit was a safe speed at the crossing. The train was in fact traveling at a speed of 37 miles per hour.

Applicable here is the rule that the violation by trainmen of the railroad’s own speed regulations adopted in the interest of safety is evidence of negligence.3 The rule has special force in the instant-case because of the unusually hazardous nature of the crossing. We find, as did the *648Court of Appeal, that the trainmen were negligent in operating the train 12 miles per hour in excess of the speed limit.

As one of several defenses, the defendant railroad strenuously contends that the excessive speed of the train was not a proximate cause of the collision for the reason that the accident would not have been averted even had the train been traveling at the prescribed speed of 25 miles per hour. Contrariwise, the plaintiff contends that the speed of the train constituted a “proximate, direct and contributing cause” of the accident.

Thus presented, the prime issue in this case is whether the excessive speed of the train was a cause in fact4 of the fatal collision.

It is fundamental that negligence is not actionable unless it is a cause in fact of the harm for which recovery is sought.5 It need not, of course, be the sole cause. Negligence is a cause in fact of the harm to another if it was a substantial factor in bringing about that harm. Under the circumstances of the instant case, the excessive speed was undoubtedly a substantial factor in bringing about the collision if the collision would not have occurred without it. On the other hand, if the collision would have occurred irrespective of such negligence, then it was not a substantial factor.6

The burden of proving this causal link is upon the plaintiff.7 Recognizing that the fact of causation is not susceptible of proof to a mathematical certainty, the law requires only that the evidence show that it is more probable than not that the harm was caused by the tortious conduct of the defendant.8 Stated differently, it must appear that it is more likely than not that the harm would have been averted but for the negligence of the defendant. .

In the instant case the train engineer testified that at a speed of 25 miles per hour he would have been unable to stop the train in time to avoid the accident. Other facts of record support his testimony in this regard. With efficient brakes, the mile-long train required 1250 feet to stop at a speed of 37 miles per hour. It is clear, then, that even at the concededly safe speed of 25 miles per hour, the momentum of the train would have, under the circumstances, carried it well beyond the crossing. This finding, of course, does not fully determine whether the collision would have been averted at the slower speed. The automobile was also in motion during the crucial period. This necessitates the further inquiry of whether the automobile would have cleared the track and evaded the impact had the train been moving at a proper speed at the time the trainmen observed the automobile emerge from behind the warehouse.9 Basic to this inquiry are the *649speed of the automobile and the driving distance between it and a position of safety.

The testimony of the witnesses is in hopeless conflict as to the speed of the automobile at the time of the collision. The estimates range from a low of 3 miles per hour to a high of 25 miles per hour. Both the district court and Court of Appeal concluded that the speed of the automobile had not been definitely established. Each of these courts found only that the automobile was proceeding at “a slow speed.” In her brief the plaintiff states: “The speed of the automobile cannot be determined, at least by the testimony.” We conclude that the evidence fails to establish the speed of the automobile with reasonable certainty.

Although the record discloses that the train struck the automobile broadside, it does not reflect the driving distance required to propel the vehicle from the danger zone.

Finally, we also note that the defendant railroad produced testimony, which is the only testimony of record on this point, that the deceased made no attempt to leave the moving automobile. That he was in the vehicle when it came to rest is undisputed. Moreover, the record fails to reflect the distance required for the deceased to scramble past the diesel engine to a place of safety, had he succeeded in getting out of the automobile.

Despite these deficiencies in the evidence, the plaintiff argues that had the train been traveling at a proper speed the driver of the automobile would “conceivably” have had some additional time to take measures to avert disaster and the deceased would have had some additional time to extricate himself from danger. Hence, the plaintiff reasons, the collision and loss of life “might not” have occurred.

On the facts of this case, we must reject the escape theory advanced in this argument. Because of the deficiencies in the evidence which we have already noted, it is devoid of evidentiary support. The record contains no probative facts from which the Court can draw a reasonable inference of causation under this theory. In essence, the argument is pure conjecture.

Based upon the evidence of record, it appears almost certain that the fatal accident would have occurred irrespective of the excessive speed of the train. It follows that this speed was not a substantial factor in bringing about the accident.

We conclude that the plaintiff has failed to discharge the burden of proving that the negligence of the defendant was a cause in fact of the tragic death. The judgment in favor of plaintiff is manifestly erroneous.

For the reasons assigned, the judgment of the Court of Appeal is reversed, and the plaintiff’s suit is dismissed at her cost.

HAMITER, J., dissents, being of the opinion that the decree of the Court of Appeal should be affirmed.

HAMLIN, J., dissents with written reasons.

HAMLIN, Justice

(dissenting).

I am compelled to agree with the Court of Appeal that in view of the blind crossing the overspeeding by the employees of the Railroad Company was negligence, which was a proximate cause of the accident.

It is my opinion that this train (approxii mately on mile long, made up of one hundred and thirteen cars and four diesels) should not have entered the Town of Vinton at thirty-seven miles per hour, its speed at the time of the accident. Notwithstanding the rules of the Railroad Company that its speed in Vinton should not have exceeded twenty-five miles per hour, even this speed, under the circumstances found by the Court of Appeal, would be excessive.

I respectfully dissent.

Opinion

HASTINGS, J.

Appellant Andrew Sanchez, a pitcher, was seriously injured when struck by a line drive hit by an aluminum bat. He filed suit *707against the bat manufacturer and others alleging that the design and use of this particular bat significantly increased the inherent risk in the sport of baseball that a pitcher would be hit by a line drive. Defendants moved for summary judgment asserting primary assumption of the risk and that appellant would be unable to prove causation. The trial court granted summary judgment when it concluded that appellant would be unable to prove that his injuries resulted from the alleged increased risk the particular bat posed to pitchers. We reverse. Appellant presented sufficient evidence to establish that use of this particular bat significantly increased the inherent risk that a pitcher would be hit by a line drive and that the unique design properties of this bat were the cause of his injuries.

Factual and Procedural Background

On April 2, 1999, appellant, pitching for California State University, Northridge (CSUN), was struck by a line drive off the bat of a player for the University of Southern California (USC), Dominic Correa. Appellant suffered serious head injuries from the incident. Correa was using an aluminum bat, the Air Attack 2, designed and manufactured by respondent Hillerich & Bradsby Co. (H&B).

USC was a member of the Pac-10, a collegiate athletic conference. The Pac-10 was a member of the National Collegiate Athletic Association (NCAA), a nonprofit organization of collegiate athletic conferences and other institutions. The NCAA establishes rules for equipment used in athletic events, including baseball bats. CSUN was a member of the NCAA, but not a member of the Pac-10.

The bat used by Correa was a newly designed hollow aluminum alloy bat with a pressurized air bladder which, according to its designer, substantially increases the speed at which the ball leaves the surface of the bat. Correa was supplied with the bat pursuant to an agreement between USC and H&B, which provided that USC would receive compensation for using H&B’s Louisville Slugger equipment exclusively. At the time of the accident, the NCAA rules allowed the use of metal bats, and the bat was made in compliance with NCAA standards. However, prior to the start of the 1999 season, the NCAA notified athletic conferences under its umbrella, including the Pac-10, of the dangerous nature of the newer metal bats and of its decision to implement new rules to decrease the speed of the batted balls effective August 1, 1999. The Pac-10 implemented some of the proposed standards prior to the 1999 baseball season.

Prior to the commencement of the 1999 baseball season, appellant had signed a disclaimer form acknowledging that his participation on the team *708carried a risk of injury, specifically including brain damage, and consenting to assume the risk of such injury.

At the time of the injury, appellant and all of his team members were using metal bats, and appellant had used a metal bat in organized baseball games since he was six years old.

On March 17, 2000, appellant filed a lawsuit against H&B, USC, NCAA and Pac-10 asserting causes of action for products liability and negligence. Appellant later struck the product liability claim against USC and the Pac-10.

Each defendant moved separately for summary judgment. H&B’s motion was based on the following grounds: (1) that appellant could not establish causation as a matter of law; (2) the action was barred by the doctrines of primary assumption of risk and express assumption of risk; and (3) that H&B was entitled to judgment because the bat was in compliance with rules established by the NCAA.

In support of its motion, H&B submitted portions of deposition testimony from various witnesses. Mike Batesole, one of appellant’s coaches, testified that he saw the incident, he had seen other pitchers hit by batted balls before, and that the risk of a pitcher being hit by a batted ball is inherent in the sport of baseball. Dominic Correa, the batter, also testified that he saw the ball strike appellant in the temple and saw appellant fall to the ground. He had no opinion about the speed of the ball. Michael Gillespie, the head coach for USC, testified that the game was not videotaped. He also testified that in his opinion, metal bats do not perform differently from wood bats. He believed that the bat used by Correa met NCAA standards, but had no specific information to confirm whether it did nor not. Marty Archer, the president of H&B, testified that he had instructed his employees to make bats which conformed with the regulations of the various regulatory bodies involved and that H&B did so construct the bats. He also stated that H&B had never given money to the NCAA to influence it. Rhonda Hyatt, the head athletic trainer for CSUN, testified that when presenting the disclaimer form to baseball players, she normally would read to them the clause about assumption of risk word for word before they signed it. At deposition, appellant testified he was aware that pitchers were at risk for being hit by a line drive.

The motion by the NCAA also contended that the doctrine of primary assumption of risk barred appellant’s claim against it and that appellant could not establish causation. In addition, it argued that it did not owe a duty to appellant because at the time of the accident the baseball community was *709in significant disagreement over the risk of aluminum bats. The NCAA submitted numerous documents in support of its motion which the trial judge did not consider because they were not properly authenticated.

USC and the Pac-10 based their motion on primary assumption of risk, arguing that a pitcher being struck by a batted ball was a risk inherent in the sport of baseball.

In opposition to each of the motions, appellant argued that primary assumption of risk was not applicable because of an increased risk presented by the Air Attack 2 over that of other bats previously in use and that the increased risk was a substantial cause of appellant’s injuries. In support, he submitted four declarations.

Jack Mackay, the designer of the Air Attack 2, declared that he had been a designer and tester of bats for nine years and was a paid consultant for H&B’s Louisville Slugger division. Mackay was present when time studies were performed on the bat at a Louisville Slugger testing center. He stated that the invention allowed a batter to hit a ball at speeds in excess of that which would have given a pitcher time to avoid being hit. As a result, he opined that the Air Attack 2 substantially increased the risk of a pitcher being hit by what he termed a “come backer.” Mackay complained to his employers at the Louisville Slugger division of H&B about the increased risks of injuries, but the complaints were ignored and Marty Archer, president of the division, warned Mackay that he should not publicly discuss issues of safety.

William Thurston, a college baseball coach and editor of the NCAA Baseball Rules Committee from February 1985 to July 2000, had initiated an NCAA study tracking pitcher injuries from high-performance aluminum bats. He concluded that the Air Attack 2 substantially increased the risk of a pitcher being hit by a line drive over the risk associated with wood bats or earlier generations of nonwood bats. He also compiled an analysis of statistics of college hitters and batters for the years 1997-2001, comparing their performance when using wooden bats versus aluminum bats and concluded there was a tremendous increase in hits and runs when aluminum bats were used.

The deposition transcript of Rhonda Hyatt was also submitted. She testified that Justin Kiersby, the student athletic trainer for appellant’s team, was in the dugout when the ball was hit and wrote down his observation that the ball was sent back at appellant at over 100 miles per hour.

Appellant also submitted the declaration of James G. Kent, who had a Ph.D. in kinesiology. Based on his training and review of the evidence, he *710opined that the ball which struck appellant’s head was traveling between 101 and 107.8 miles an hour, probably closer to the latter speed than the former. This would have left appellant a reaction time of .32 to .37 seconds to avoid the ball. This was below the minimum reaction time accepted by the NCAA and other organizations of .39 seconds. As a result, he concluded that appellant’s head injury resulted from the increased danger posed by this particular bat.

The superior court granted the motions of H&B, USC and Pac-10 on the ground that appellant would not be able to prove causation. But it concluded that it could not grant summary judgment to NCAA because of NCAA’s failure to submit admissible evidence. Instead, it treated the NCAA’s motion as one for judgment on the pleadings and concluded that appellant would not be able to truthfully plead causation against the NCAA. As pertinent, its order states:

“Nowhere in the 21 paragraphs of the complaint does [appellant] allege that the defective bat caused the injuries suffered by [appellant]. All he alleges is that the allegedly defective product and defendants’ negligence increased the risk that [appellant] would be injured. Increased risk is not actionable. [Appellant] has to plead, and then prove, a sufficient causal connection between defendants’ negligence and the injury, [f] ... ffl]

“[Appellant’s] submissions in opposition to the summary judgment motion were insufficient to show that H&B’s alleged negligence was an actual, legal cause of plaintiffs injuries. [Appellant] does not dispute that there was no videotape of the incident. The deposition transcripts of Kiersby indicates that the ball was so fast he does not know if anyone observed it, including him, and there was no foundation for the conclusion set forth in the notes attached to Ms. Hyatt’s deposition. Lastly, the expert testimony set forth in the Declaration of James Kent, Ph.D., who has rendered an opinion about the exit velocity, is without foundation. Dr. Kent saw no videotape of the incident, nor did he examine [appellant]. All he did was review the videotape of [appellant] pitching prior to the date of the injury and some deposition transcripts. Like in the Saelzler case, [appellant’s] expert is deprived of a key piece of evidence and his opinion is too tenuous to create a triable issue as to whether the exit velocity caused [appellant’s] injuries. . . .

“[USC] and the Pac-10 also argue that [appellant] cannot prove causation and set forth . . . that [appellant] does not have all the information necessary to determine the speed of the baseball, adding that a range of potential speeds will be calculated by experts. The causation evidence offered by [appellant] in response is the same as that offered in response to H&B’s causation argument . . . and is equally insufficient.

*711“[NCAA] did not submit any admissible evidence; [appellant’s] foundation and hearsay objections were well-taken. . . . Again, [appellant’s] evidence is insufficient to establish causation. Since the NCAA did not submit admissible evidence, the court cannot grant summary judgment. However, [appellant] has shown no ability to truthfully and accurately amend its complaint to show causation of the alleged injuries. Thus, the court will treat the NCAA’s motion as a motion for judgment on the pleadings and, since ... the court has determined that [appellant] cannot state a cause of action, no leave to amend is granted.”

Further facts will be presented in connection with our discussion.

Discussion

In determining whether summary judgment was properly granted, we review de novo all of the admissible evidence set forth in the moving and opposing papers to determine whether there are any triable issues of material fact. If not, and the moving party is entitled to judgment as a matter of law, summary judgment is properly granted. The defendant moving for summary judgment must present facts to negate an essential element of the plaintiff’s case or to establish a defense. If it does so, the burden shifts to the plaintiff to demonstrate a triable issue of material fact. (Lowe v. California League of Prof Baseball (1997) 56 Cal.App.4th 112, 122 [65 Cal.Rptr.2d 105]; Ferrari v. Grand Canyon Dories (1995) 32 Cal.App.4th 248, 252 [38 Cal.Rptr.2d 65].)

We construe the moving parties’ declarations strictly, and those of appellant’s, liberally. (Arnold v. Dow Chemical Co. (2001) 91 Cal.App.4th 698, 707 [110 Cal.Rptr.2d 722].) Any doubts are to be resolved against granting the motion. (Molko v. Holy Spirit Assn. (1988) 46 Cal.3d 1092, 1107 [252 Cal.Rptr. 122, 762 P.2d 46].)

1. Assumption of Risk

In the companion cases of Knight v. Jewett (1992) 3 Cal.4th 296 [11 Cal.Rptr.2d 2, 834 P.2d 696] and Ford v. Gouin (1992) 3 Cal.4th 339 [11 Cal.Rptr.2d 30, 834 P.2d 724, 34 A.L.R.5th 769], our Supreme Court addressed the distinction between the principles of assumption of the risk and comparative fault and adopted the phrases “primary assumption of risk” for the former and “secondary assumption of risk” for the latter. It did so in connection with its discussion of Li v. Yellow Cab (1975) 13 Cal.3d 804 [119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393]:

“[T]he distinction to which the Li court referred was between (1) those instances in which the assumption of risk doctrine embodies a legal conclusion that there is ‘no duty’ on the part of the defendant to protect the plaintiff *712from a particular risk—the category of assumption of risk that the legal commentators generally refer to as ‘primary assumption of risk’—and (2) those instances in which the defendant does owe a duty of care to the plaintiff but the plaintiff knowingly encounters a risk of injury caused by the defendant’s breach of that duty—what most commentators have termed ‘secondary assumption of risk.’ . . .

“. . . First, in ‘primary assumption of risk’ cases—where the defendant owes no duty to protect the plaintiff from a particular risk of harm—a plaintiff who has suffered such harm is not entitled to recover from the defendant, whether the plaintiffs conduct in undertaking the activity was reasonable or unreasonable. Second, in ‘secondary assumption of risk’ cases—involving instances in which the defendant has breached the duty of care owed to the plaintiff—the defendant is not entitled to be entirely relieved of liability for an injury proximately caused by such breach, simply because the plaintiffs conduct in encountering the risk of such an injury was reasonable rather than unreasonable. Third and finally, the question whether the defendant owed a legal duty to protect plaintiff from a particular risk of harm does not turn on the reasonableness or unreasonableness of the plaintiffs conduct, but rather on the nature of the activity or sport in which the defendant is engaged and the relationship of the defendant and the plaintiff to that activity or sport.” (Knight v. Jewett, supra, 3 Cal.4th at pp. 308-309, italics in original and fns. omitted.)

When addressing the applicability of primary assumption of the risk, we analyze the nature of the activity and the role of each of the parties to that activity and decide as a matter of public policy whether the defendant should owe the plaintiff a duty of care. (Shannon v. Rhodes (2001) 92 Cal.App.4th 792, 795 [112 Cal.Rptr.2d 217].) A defendant owes no duty of care to protect a plaintiff against risks inherent in a particular sport voluntarily played by the plaintiff. But the defendant owes a duty to participants not to increase the risk of harm over and above that inherent in the sport. (American Golf Corp. v. Superior Court (2000) 79 Cal.App.4th 30, 36-37 [93 Cal.Rptr.2d 683]; Bush v. Parents Without Partners (1993) 17 Cal.App.4th 322, 329 [21 Cal.Rptr.2d 178]; Branco v. Kearny Moto Park, Inc. (1995) 37 Cal.App.4th 184, 190 [43 Cal.Rptr.2d 392].) The standards in the industry define the nature of the sport. (American GolfCorp., supra, at p. 37; Bush, supra, at p. 328; Branco, supra, at p. 190; Ferrari v. Grand Canyon Dories, supra, 32 Cal.App.4th at p. 257.) If it is determined that the actions of a defendant did increase the risk of harm above that inherent in the sport, primary assumption of the risk is not available and the issue becomes one of secondary assumption of the risk. (Branco v. Kearny Moto Park, Inc., supra, 37 Cal.App.4th at p. 193.)

*713A risk is inherent in a sport if its elimination (1) would chill vigorous participation in the sport; and (2) would alter the fundamental nature of the activity. (Ferrari v. Grand Canyon Dories, supra, 32 Cal.App.4th at p. 253.)

The essence of a baseball game is the contest between the defense, the pitcher and other players in the field, and the batter, for mastery over what happens to the pitched ball. The batter wants to hit the ball safely, usually away from the defense, so that the batter can advance on the bases. The defense wants to get the batter out, either by striking the batter out, or by causing the batter to hit the ball to a spot where one of the defensive players can make a play on it. Inherent in this mix is the risk that the pitcher, or any infielder, may have to catch, or avoid being hit with, a sharply batted ball. Appellant acknowledged he was aware of this risk. Thus, given the foundational facts of this case, a prima facie showing of assumption of the risk has been established. But appellant argued that use of the Air Attack 2 increased the risk above that inherent in the sport, and presented evidence on the issue. We now review that evidence.

At the time of the accident, the NCAA allowed the use of metal bats, and the bat in use was apparently in compliance with NCAA standards. It is undisputed that the Air Attack 2 was designed to cause the ball to come off the bat at a higher launch speed than with wooden bats and older metal bats. It is also undisputed that the inventor of the Air Attack 2 believed the Air Attack 2 substantially increased the risk of a pitcher being hit by what he termed a “come backer” and that he complained to his employers at H&B about these increased risks.

Additionally, the evidence submitted by appellant establishes that the Pac-10 and NCAA each believed that new generations of aluminum bats created a significant issue of safety. Before the incident at issue, the NCAA adopted new rules to regulate the exit speed of such bats, but postponed implementation of the rules until a date after this incident. On October 8, 1998, Thomas Hansen, commissioner of the Pac-10, sent a letter of protest to the NCAA about delayed implementation of the rules:

“I am writing on behalf of the Pacific-10 Conference Directors of Athletics to request that the NCAA reconsider its decision to postpone until August 1, 1999, a change in nonwood baseball bat specifications.

“We believe in light of the contents of your letter of August 28, 1998, that a change prior to the 1999 season is imperative. The comments of the NCAA Baseball Rules Committee and the NCAA Committee on Competitive Safeguards and Medical Aspects of Sports warn of the dangers of using the *714current bats. Since we consider the safety of competing student-athletes paramount, we believe an immediate change is in order since games are being played at this time.

“The Association’s decision has left each conference and institution in an untenable legal position prior to August 1, 1999. Accordingly, we request reconsideration of this matter at the earliest possible time.”

The NCAA not only believed that the newer aluminum bats created an increased risk of harm to players, it also believed that use of these bats changed the nature of the sport of college baseball. We quote from portions of a letter dated December 4, 1998, and sent by the NCAA Baseball Rules Committee to “Chief Executive Officers” “Directors of Athletics” “Head Baseball Coaches” and “Conference Commissioners”:

“The NCAA adopted the new bat rule after a lengthy, careful and fair deliberative process. The baseball rules committee, composed of knowledgeable baseball coaches and administrators with many years of experience, has been concerned about runaway bat performance for many years. In 1988, 1993, 1994, 1995, 1996, 1997 and 1998, the committee studied the issue and took steps that it believed would reasonably curtail ever-increasing aluminum bat performance. The committee’s efforts in this regard were not successful, with the result that the performance level of aluminum bats continued to escalate. The committee has continuously monitored available statistics, participated in various studies supported by the manufacturers, and, until recently, trusted the information provided by the bat manufacturers. In some cases, the information has been less than trustworthy.

“Alarmed by the continuing increase in performance, the anecdotal and statistical evidence that the game of college baseball has been significantly altered by aluminum bat performance, and concerned about the increased safety risk, the committee determined to study the matter in depth in the summer of 1998. The committee convened a meeting in Kansas City, Missouri, in July 1998. All interested manufacturers, experts, and other knowledgeable persons were invited to make presentations to the committee in open session. The proceedings were stenographically recorded and the results are available should you wish to examine them. The committee was unanimously convinced that bat performance was indeed a safety risk to pitchers and infielders, that there has indeed been a change in the way the college game of baseball is played, and that the available evidence was more than sufficient to justify a change in the rule as soon as practically possible There is simply no question that aluminum bats substantially outperform traditional wood bats, that the risk of injury to pitchers and infielders is real, *715 and that a performance limit on the aluminum bats was required to bring the game of baseball closer to its traditional form.” (Italics added.)

This case is similar to Branco v. Kearny Moto Park, Inc., supra, 37 Cal.App.4th 184. There, participants on bicycles raced around a motocross (BMX) course which contained “jumps” as part of the course. The plaintiff was injured when he crashed and struck the side wall of the landing area of what is described as “an expert caliber jump.” (Branco v. Kearny Moto Park, Inc., supra, 37 Cal.App.4th at p. 187.) He filed suit and the defendants asserted primary assumption of the risk. The trial court granted summary judgment for defendants but the Court of Appeal reversed. “It is not unreasonable to expect a BMX course to refrain from utilizing jumps which by design create an extreme risk of injury. Certainly the jumps, and falls, are inherent to the sport, and under the doctrine of primary assumption of risk, there is no duty to eliminate the jumps entirely, and no duty to protect from injury arising from reasonably designed jumps. However, the sport does not inherently require jumps which are designed in such a way as to create an extreme risk of injury. Accordingly, premised on the duty not to utilize dangerously designed jumps, this case falls under the secondary assumption of risk category, and issues pertaining to [the plaintiffs] comparative fault are for the trier of fact to decide. [The plaintiffs] expert’s opinions regarding the design of the jump create a triable issue of material fact whether the million dollar jump was designed in such a way as to create an extreme risk of injury.” (Branco v. Kearny Moto Park, Inc., supra, 37 Cal.App.4th at p. 193, fns. omitted.)

Here, appellant’s evidence raises a triable issue of material fact whether the design and use of the Air Attack 2 substantially increased the inherent risk appellant faced. The evidence also raises at least a triable issue whether defendants knew of and appreciated the nature of the increased risk. The letters from the Pac-10 and the NCAA clearly establish they were aware of the additional danger presented by the newer aluminum bats. The NCAA letter was addressed to all “Head Coaches” and from that we can infer that the USC head coach was placed on notice of the increased risk, since USC was under the NCAA’s umbrella. Mackay’s declaration states that he warned H&B of the increased risk.

If it is ultimately determined primary assumption of the risk does not apply here, the issue then becomes one of secondary assumption of the risk. Comparing the relative fault of plaintiff and defendants is a question of fact that must be resolved by a trier of fact and cannot be resolved by way of a summary judgment motion. (Donohue v. San Francisco Housing Authority (1993) 16 Cal.App.4th 658, 666 [20 Cal.Rptr.2d 148]; Davis v. Gaschler (1992) 11 Cal.App.4th 1392, 1398 [14 Cal.Rptr.2d 679].)

*7162. Causation

Respondents contended, and the trial court agreed, that because the speed of the ball leaving the bat was never established, no causation attributed to the increased risk of use of the Air Attack 2, if any, could be established. Respondents cite to Saelzler v. Advanced Group 400 (2001) 25 Cal.4th 763 [107 Cal.Rptr.2d 617, 23 P.3d 1143] for the proposition that summary judgment cannot be granted when causation is not established. Saelzler does stand for that proposition. But application of Saelzler to the instant case is not as facile as argued by respondents. In Saelzler, a visitor to an apartment complex was attacked by three unidentified men at the complex, and she sought to impose liability on the owner for maintaining an unsafe premises. The Supreme Court concluded that without knowledge of who the attackers were it would be impossible to prove that any negligence on behalf of the owner of the complex was connected with the attack. Here, however, the connection is not so tenuous.

It is undisputed that Correa, using an Air Attack 2 manufactured by H&B, provided by USC, and approved by the NCAA, hit the ball that fractured appellant’s skull. It is also undisputed that the Air Attack 2 was designed to and did increase the speed at which the baseball leaves the bat compared to other metal and wood bats. Thus, absent other factors (none are suggested) it follows that the ball must have reached appellant sooner than if Correa had used a bat other than the Air Attack 2. Dr. Kent opined that the ball that hit Correa was traveling at a speed of up to 107.8 miles per hour, giving appellant a reaction time of between .32 and .37 seconds, below the acceptable minimum time recognized by the NCAA.

The trial court concluded that Dr., Kent’s declaration was without foundation because he “saw no videotape of the incident, nor did he examine [appellant]. All he did was review the videotape of [appellant] pitching prior to the date of the injury and some deposition transcripts.” This does not accurately reflect what was set out in his declaration.

We first note that Dr. Kent attached his curriculum vitae to his declaration. It establishes that Dr. Kent has a Ph.D. in physical education, with a specialty in clinical kinesiology. He is a diplomat of the American Board of Forensic Medicine and of the American Board of Forensic Examiners. He describes his work experience from 1983 to present as follows: “Consulting services in Forensic and Occupational Kinesiology, specializing in the analysis of biomechanics of trauma, human performance analysis, clinical rehabilitation medicine and biomechanical accident reconstruction.” (Italics added.) We now quote from the pertinent portions of his declaration:

*717“4. I have reviewed medical records regarding Mr. Sanchez’s anatomic injuries as a result of this subject event. I have reviewed archival videotape footage of Mr. Sanchez pitching prior to the date of injury. I have reviewed the deposition transcripts of Mr. Sanchez, Justin Kiersby and Michael Gillespie. I have also reviewed and relied upon literature regarding skull fracture and traumatic brain injury biomechanics, National Collegiate Athletic Association (NCAA) Baseball rules and safety standards, and the Consumer Products Safety Commission (CPSC) and researchf] conducted under the auspices of Hillerich & Bradsby (H&B). Based upon my review of all of these materials, my training and experience, I have also completed quantitative analysis regarding the velocity necessary to cause Mr. Sanchez’s injury pattern. I then compared the resulting ball flight time to the safety criteria established by the NCAA, CPSC and H&B sponsored literature. Based upon this analytic process, I have formed the opinions to follow.

“5. Analysis of skull fracture threshold biomechanics in conjunction with quantitative analysis utilizing basic principles of dynamics related to the flight of a baseball demonstrate that the ball which struck Mr. Sanchez’s head was traveling at a velocity not less [than] 101 (101.3) miles per hour and most probably was traveling at a velocity approximating 108 (107.8) miles per hour.

“6. Based on the conclusions stated above regarding ball velocity at impact, and using a range of distance from bat-ball strike to ball-head impact of 52 to 55 feet, the time period from bat-ball impact to ball-head impact ranges from not more than 0.37 seconds [to] not less than 0.329 seconds. The most probable time period was 0.335 to 0.342 seconds based upon a most probable distance of 53 to 54 feet with an impact velocity of 108 miles per hour.

“7. Based on the breadth of the literature reviewed to date as cited above, it appears that the NCAA as well as other individuals and organizations, including H&B, have concluded that 0.39 to 0.40 second is the time period over which a college pitcher can reasonably be expected to deflect a baseball as it travels from a bat strike towards their post-delivery fielding position. As a result, Mr. Sanchez was confronted with a significant reduction in the time available to him to deflect the ball which ultimately struck him versus the recommended and apparently accepted time range of 0.39 to 0.40 seconds.

“8. Based upon my analysis of this matter, it is more probable than not that Mr. Sanchez’s head injury resulted from the use of a baseball bat which possessed mechanical properties allowing a batted ball to attain a flight *718velocity in excess of a velocity that would allow for a reasonable reaction time by a pitcher in a post-delivery posture in a game situation.” (Italics added.)

Respondents did not object to Dr. Kent’s qualifications. Instead, citing to People v. Leahy (1994) 8 Cal.4th 587 [34 Cal.Rptr.2d 663, 882 P.2d 321] and People v. Kelly (1976) 17 Cal.3d 24 [130 Cal.Rptr. 144, 549 P.2d 1240], and other cases, they argued that his declaration was deficient because it failed to explain the nature and type of calculations used to determine the speed of the ball and whether the type of calculations he performed were accepted by the scientific community at large. We cannot agree.

Cases dismissing expert declarations in connection with summary judgment motions do so on the basis that the declarations established that the opinions were either speculative, lacked foundation, or were stated without sufficient certainty. (See Ochoa v. Pacific Gas & Electric Co. (1998) 61 Cal.App.4th 1480, 1487 [72 Cal.Rptr.2d 232]; Thai v. Stang (1989) 214 Cal.App.3d 1264, 1276 [263 Cal.Rptr. 202].) That is not the situation here. It is sufficient, if an expert declaration establishes the matters relied upon in expressing the opinion, that the opinion rests on matters of a type reasonably relied upon, and the bases for the opinion. (Kelley v. Trunk (1998) 66 Cal.App.4th 519, 524 [78 Cal.Rptr.2d 122].)

As previously noted, respondents did not challenge Dr. Kent’s credentials. He is a kinesiologist who, since 1983, has specialized “in the analysis of biomechanics of trauma.” His declaration establishes that in forming his opinions he reviewed appellant’s medical records, relied upon “literature regarding skull fracture and traumatic brain injury biomechanics,” undertook a quantitative analysis regarding “velocity necessary to cause Mr. Sanchez’s injury pattern” and “utilizing basic principles of dynamics related to the flight of a baseball” reached an opinion about the range of speed of the ball which hit appellant. While he does not spell out the actual calculations he used, the declaration is not deficient for purposes of summary judgment. If respondents had desired to do so, they could have deposed Dr. Kent in an attempt to demonstrate his opinions had no basis in fact or science. (St. Mary Medical Center v. Superior Court (1996) 50 Cal.App.4th 1531, 1538-1539 [58 Cal.Rptr.2d 182].)

Dr. Kent also relied upon literature from the NCAA regarding reaction times. The letter from the NCAA dated December 4, 1998, quoted above, also has a passage regarding reaction times: “Most of the experts providing information to the Baseball Rules Committee believe that a collegiate pitcher needs approximately .4 seconds to react and move to avoid being struck. *719. . . Most baseball experts believe that a pitcher is between 51 and 52 feet away from the point of impact between the bat and ball at the time of impact, usually in an off-balance position with his glove down and back, and his weight moving forward. At 94 mph the ball will travel 52 feet in approximately .371 seconds. Game conditions using high powered aluminum bats often result in speeds well in excess of 100 mph. At 100 mph, the ball will travel 52 feet in .354 seconds; at 110 mph, a ball will travel 52 feet in .321 seconds. The NCAA Baseball Rules Committee is aware that there is some risk even with wood bats, but believes that the increased risk of injury resulting from the use of high powered aluminum bats is clear. To ignore this risk would, in our opinion, be irresponsible.”

This provides independent corroboration for some of the facts relied upon by Dr. Kent and provides further facts relevant to the issue of causation.

We conclude the evidence presented by appellant is sufficient to create a triable issue of fact regarding causation. (Saffro v. Elite Racing, Inc. (2002) 98 Cal.App.4th 173, 180 [119 Cal.Rptr.2d 497]; Box v. California Date Growers Assn. (1976) 57 Cal.App.3d 266, 274 [129 Cal.Rptr. 146].)

3. Summary Adjudication on the Claim for Punitive Damages

H&B contends that in the event that summary judgment is reversed, this court should address its motion for summary adjudication on appellant’s claim for punitive damages. Because the trial court did not reach this issue in the first instance, we believe it best that the trial court be given the opportunity to do so upon remand.

4. NCAA Cross-appeal

NCAA filed a cross-appeal contending that the lower court erred in finding that NCAA did not submit admissible evidence in conjunction with its summary judgment motion. NCAA submitted 29 exhibits in conjunction with its motion, along with a declaration of Gregory Curtner, its general counsel, attesting to the authenticity of those documents.1 Appellant never filed a written objection to these exhibits, but the trial court ruled that an attorney could not authenticate the exhibits.

Curtner’s declaration stated in pertinent part: “I am admitted to practice in this action pro hac vice. I am familiar with the NCAA having represented it *720in many matters. I am also familiar with the documents, events, and issues relating to the use of non-wood bats in the game of baseball having represented the NCAA in several matters relating to bats, having deposed or interviewed most of the knowledgeable individuals on the bat issues, and having read the relevant literature on bat issues, [f] Attached hereto are true and correct copies of the Exhibits to the NCAA’s Memorandum of Points and Authorities in Support of Motion for Summary Judgment. . . . [listing titles of various documents].” The declaration did not specify that he was the custodian of these exhibits, or that these documents were prepared, in the regular course of business, or that he personally prepared these documents or knew of the conditions under which they were prepared so that he could verify their trustworthiness. (Evid. Code, § 1271.)

Curtner’s declaration did not provide a foundation for admissibility. It contained no evidence as to how the reports were prepared or upon what sources of information they were based, or any evidence that the reports were trustworthy. The exhibits therefore could not be admitted as business records. (Taggart v. Super Seer Corp. (1995) 33 Cal.App.4th 1697, 1706 [40 Cal.Rptr.2d 56].) The trial court correctly ruled that they were inadmissible.

Given that the trial court’s determination in favor of the NCAA was based on its conclusion that appellant would be unable to truthfully plead causation, and we have found sufficient evidence to raise a triable issue of fact on causation, the trial court’s grant of judgment on the pleadings in favor of the NCAA must also be reversed.

Disposition

The judgment is reversed and the matter is remanded to the trial court. Costs are awarded to appellant.

Epstein, Acting P. J., and Curry, J., concurred.

Respondents’ petitions for review by the Supreme Court were denied March 26, 2003.

In a negligence action to recover damages for personal injury, plaintiff appeals from a judgment of the Supreme Court, Queens County, entered June 21,1965, which dismissed the complaint as against defendant Bragoli upon the court’s decision at the close of plaintiff’s case upon a jury trial. Judgment reversed, on the law, and new trial granted, with costs to appellant to abide the event. No questions of fact have been considered. At the close of plaintiff’s case the court dismissed the complaint against the owner of a tractor truck who on a stormy night left it parked without lights in the middle of a road where the car in which plaintiff was a passenger collided with it from the rear. From the testimony of the driver of the car the court concluded that she was guilty of negligence and was solely responsible for the collision. That testimony was that she saw the truck when it was four car lengths ahead of her and that she saw it in enough time to turn. At other points, however, she indicated that she did not know just what happened, that she swerved to avoid the truck, “ and the next thing I knew I woke up. I was unconscious ”. Assuming, atguendo, that she was negligent, the accident could not have happened had not the truck owner allowed Ms unlighted vehicle to stand in the middle of the highway. Where separate acts of negligence combine to produce directly a single injury each tort-feasor is responsible for the *555entire result, even though his act alone might not have caused it (Hancock v. Steber, 208 App. Div. 455; Matthews v. State of New York, 271 App. Div. 389, affd. 296 N. Y. 946). Accordingly, the complaint against the truck owner must be reinstated and a new trial had. Christ, Acting P. J., Brennan, Hill, Rabin and Hopkins, JJ., concur.

Owen, J.

The jury found that both fires were set by sparks emitted from locomotives on and over defendant’s right of way. Appellant contends that there is no evidence to support the finding that either fire was so set. We' have carefully examined the record and have come to the conclusion that the evidence does support the finding that the northeast fire was set by sparks emitted from a locomotive then being rtm on and over the right of way of defendant’s main line. We conclude, however, that the evidence does not support the finding that the northwest fire was set by sparks *613emitted from defendant’s locomotives or that the defendant had any connection with its origin. A review of the evidence to justify these conclusions would seem to .serve no good purpose, and we content ourselves by a simple statement of the conclusions thus reached.

We therefore have this situation: The northeast fire was set by sparks emitted from defendant’s locomotive. This fire, according to the finding of the jury, constituted a proximate cause of the destruction of plaintiff’s property. This finding we find to be well supported- by the evidence. We have the northwest fire, of unknown origin. This fire, according to the finding of the jury, also constituted a proximate cause of the destruction of the plaintiff’s property. This finding we also find to be well supported by the evidence. We have a union of these two fires 940 feet north of plaintiff’s property,. from which point the united fire bore down upon and destroyed the property. We therefore have two separate, independent, and distinct agencies, each of which constituted the proximate-cause of plaintiff’s, damage, and either of which, in the absence of the other, would have accomplished such result.

It is settled in the law of negligence that' any one of two or more joint tortfeasors, or one of two or more wrongdoers whose concurring acts of negligence result in injury, are each individually responsible for the entire damage resulting from their joint or concurrent acts of negligence. This rule also obtains “where two causes, each attributable to the negligence of a responsible person, concur in producing an injury to another, either of which causes would produce it regardless of the other, . . . because, whether the concurrence be intentional, actual,, or constructive, each wrongdoer, in effect, adopts the conduct of his co-actor, and for the further reason that it is impossible to apportion the damage or to say that either perpetrated any distinct injury *614that can be separated from the whole. The whole loss must necessarily be considered and treated as an entirety.” Cook v. M., St. P. & S. S. M. R. Co. 98 Wis. 624 (74 N. W. 561), at p. 642. That case presented a situation very similar to this. One fire, originating by sparks emitted from a Iocoh motive, united with another fire of unknown origin and consumed plaintiffs’ property. There was nothing to indicate that the fire of unknown origin was not set by some human agency. The evidence in the case merely failed to identify the agency. In that case it was held that the railroad company which set one fire was not responsible for the damage committed by the united fires because the origin of the other fire was not identified. In that case a rule of law was announced, which is stated in the syllabus prepared by the writer of the opinion as follows:

“A fire started by defendant’s negligence, after spreading one mile and a quarter to the northeast, near plaintiffs’ property, met a fire having no responsible origin, coming from the northwest. After the -union, fire swept on from the northwest to and into plaintiffs’ property, causing its destruction. Either fire, if the other had not existed, would have reached the property and caused its destruction at- the same time. Held:

“(1) That the rule of liability in case of joint wrongdoers does not apply.

“(2) That the independent fire from the northwest became a superseding cause, so that the destruction of the property could not, with reasonable certainty, be attributed in whole or in part to the fire having a responsible origin; that the chain of responsible causation was so broken by the fire from the northwest that the negligent fire, if it reached the property at all, was a remote and not the proximate cause of the loss.”

Emphasis is placed upon the fact, especially in the opinion, that one fire had “no responsible origin.” At other times in the opinion the fact is emphasized that it had no “known *615responsible origin.” The plain inference from the entire opinion is that if both fires had been of responsible origin, or of known responsible origin, each wrongdoer would have been liable for the entire damage. The conclusion of the court exempting the railroad company from liability seems to be based upon the single fact that one fire had no responsible origin or no known responsible origin. It is difficult to determine just what weight was accorded to the fact that the origin of .the fire was unknown. If the conclusion of the court was founded upon the assumption that the fire of unknown origin had no responsible origin, the conclusion announced may be sound and in harmony with well settled principles of negligence.

From our present consideration of the subject we are not disposed to criticise the doctrine which exempts from liability a wrongdoer who sets a fire which unites with a fire originating from natural causes, such as lightning, not attributable to any human agency, resulting in damage. It is also conceivable that a fire so set might unite with a fire of so much greater proportions, such as a raging forest fire, as to be enveloped or swallowed up by the greater holocaust, and its identity destroyed, so- that the greater fire could be said to be an intervening or superseding cause. But we have no such situation here. These fires were of comparatively equal rank. If there was any difference in their magnitude or threatening aspect, the record indicates that the northeast fire was the larger fire and was really regarded as the menacing agency. At any rate there is no intimation or suggestion that the northeast fire was enveloped and swallowed up by the northwest fire. We will err on the side of the defendant if we regard the two fires as of equal rank.

According to well settled principles of negligence, it is undoubted that if the proof disclosed the origin of the northwest fire, even though its origin be attributed to a third per*616son, the railroad company, as the originator of the northeast fire, would be liable for the entire damage. There is no reason to believe that the northwest fire originated from any other than human agency; It was a small fire. It had traveled over a limited area. It had been in existence but for a day. For a time it was thought to have been extinguished. It was not in the nature of a raging forest fire. The record discloses nothing of natural phenomena which could have given rise to the fire. It is morally certain that it was set by some human agency.

Now the question is whether the railroad company, which is found to have been responsible for the origin of the northeast fire, escapes liability because the origin of the northwest fire is not identified, although there is no reason to believe that it had any other than human origin. An affirmative answer to that question would certainly make a wrongdoer a favorite of the law at the expense of an innocent sufferer. The injustice of such a doctrine sufficiently impeaches the logic upon which it is founded. Where one who has suffered damage by fire proves the origin of a fire and the course of that fire up to the point of the destruction of his property, one has certainly established liability on the part of the originator of the fire. Granting that the union of that fire with another of natural origin, or with another of much greater proportions, is available as a defense, the burden is on the defendant to show that by reason of such union with a fire of such character the fire set. by him was not the proximate cause of the damage. No principle of justice requires that the plaintiff be placed under the burden of specifically identifying the origin of both fires in order to recover' the damages for which either or both fires are responsible.

Speaking of the decision in the Cook Case, Thompson, in his work on Negligence, § 739, says:

“The conclusion is so clearly wrong as not to deserve discussion. It is just as though two wrongdoers, not acting in *617concert, or simultaneously, fire shots from different directions at the same person, each shot inflicting a mortal wound. Either wound being sufficient to cause death,'it would be'a childish casuistry that would engage in a debate as to which of the wrongdoers was innocent on the ground that the other was guilty.”

His illustration does not exactly answer the reason which we conceive to underlie the decision in the Cook Case. It would exactly fit it, as we understand the Cook Case, if the one who was known to have fired one of the shots should be permitted to escape liability for death because he who fired the other shot had not been identified, although it was certain that the other shot had been fired by some other human being. We are not disposed to apply the doctrine of the Cook Case to the instant situation. There being no attempt on the part of the defendant to prove that the northwest fire was due to an irresponsible origin, that is, an origin not attributable to a human being, and the evidence in the case affording no reason to believe that it had an origin not attributable to a human being, and it appearing that the northeast fire, for the origin of which the defendant is responsible, was a proximate cause of plaintiff’s loss, the defendant is responsible for the entire amount of that loss. While under some circumstances a wrongdoer is not responsible for damage which would have occurred in the absence of his wrongful act, even though such wrongful act was a proximate cause of the accident, .that doctrine does not obtain “where two causes, each attributable to the negligence of a responsible person, concur in producing an injury to another, either of which causes would produce it regardless of the other.” This is because “it is impossible to apportion the damage or to say that either perpetrated any distinct injury that can be separated from the whole,” and to permit each of two wrongdoers to plead the wrong of the other as a defense to his own wrongdoing would permit both *618wrongdoers to escape and penalize the innocent party who has been damaged by their wrongful acts.

The fact that the northeast fire was set by the railroad company, which fire was a proximate cause of plaintiff’s damage, is sufficient to affirm the judgment. This conclusion renders it unnecessary to consider other grounds of liability stressed in respondent’s brief.

By the Court. — Judgment affirmed.

CARTER, J.

Each of the two defendants appeals from a judgment against them in an action for personal injuries. Pursuant to stipulation the appeals have been consolidated.

Plaintiff’s action was against both defendants for an injury to his right eye and face as the result of being struck by bird shot discharged from a shotgun. The case was. tried by the court without a jury and the court found that on November 20, 1945, plaintiff and the two defendants were hunting quail on the open range. Each of the defendants was armed with a 12 gauge shotgun loaded with shells containing 7% size shot. Prior to going hunting plaintiff discussed the hunting procedure with defendants, indicating that they were to exercise care when shooting and to “keep in line.” In the course of hunting plaintiff proceeded up a hill, thus placing the hunters at the points of a triangle. The view of defendants with reference to plaintiff was unobstructed and they knew his location. Defendant Tice flushed a quail which rose in flight to a 10-foot elevation and flew between plaintiff and defendants. Both defendants shot at the quail, shooting in plaintiff’s direction. At that time defendants were 75 yards from plaintiff. One shot struck plaintiff in his eye and another in his upper lip. Finally it was found by the court that as *83the direct result of the shooting by defendants the shots struck plaintiff as above mentioned and that defendants were negligent in so shooting and plaintiff was not contributorily negligent.

First, on the subject of negligence, defendant Simon-son contends that the evidence is insufficient to sustain the finding on that score, but he does not point out wherein it is lacking. There is evidence that both defendants, at about the same time or one immediately after the other, shot at a quail and in so doing shot toward plaintiff who was uphill from them, and that they knew his location. That is sufficient from which the trial court could conclude that they acted with respect to plaintiff other than as persons of ordinary prudence. The issue was one of fact for the trial court. (See, Rudd v. Byrnes, 156 Cal. 636 [105 P. 957, 20 Ann.Cas. 124, 26 L.R.A. N.S.134].)

Defendant Tice states in his opening brief, “we have decided not to argue the insufficiency of negligence on the part of defendant Tice.” It is true he states in his answer to plaintiff’s petition for a hearing in this court that he did not concede this point but he does not argue it. Nothing more need be said on the subject.

Defendant Simonson urges that plaintiff was guilty of contributory negligence and assumed the risk as a matter of law. He cites no authority for the proposition that by going on a hunting party the various hunters assume the risk of negligence on the part of their companions. Such a tenet is not reasonable. It is true that plaintiff suggested that they all “stay in line,” presumably abreast, while hunting, and he went uphill at somewhat of a right angle to the hunting line, but he also cautioned that they use care, and defendants knew plaintiff’s position. We hold, therefore, that the trial court was justified in finding that he did not assume the risk or act other than as a person of ordinary prudence under the circumstances. (See, Anthony v. Hobbie, 25 Cal.2d 814, 818 [155 P.2d 826] ; Rudd v. Byrnes, supra.) None of the cases cited by Simonson are in point.

The problem presented in this case is whether the judgment against both defendants may stand. It is argued by defendants that they are not joint tort feasors, and thus jointly and severally liable, as they were not acting in concert, and that there is not sufficient evidence to show which defendant was guilty of the negligence which caused the injuries—the shooting by Tice or that by Simonson. Tice argues that there is *84evidence to show that the shot which struck plaintiff came from Simonson’s gun because of admissions allegedly made by him to third persons and no evidence that they came from his gun. Further in connection with the latter contention, the court failed to find on plaintiff’s allegation in his complaint that he did not know which one was at fault—did not find which defendant was guilty of the negligence which caused the injuries to plaintiff.

Considering the last argument first, we believe it is clear that the court sufficiently found on the issue that defendants were jointly liable and that thus the negligence of both was the cause of the injury or to that legal effect. It found that both defendants were negligent and “That as a direct and proximate result of the shots fired by defendants, and each of them, a birdshot pellet was caused to and did lodge in plaintiff’s right eye and that another birdshot pellet was caused to and did lodge in plaintiff’s upper lip.” In so doing the court evidently did not give credence to the admissions of Simonson to third persons that he fired the shots, which it was justified in doing. It thus determined that the negligence of both defendants was the legal cause of the injury—or that both were responsible. Implicit in such finding is the assumption that the court was unable to ascertain whether the shots were from the gun of one defendant or the other or one shot from each of them. The one shot that entered plaintiff’s eye was the major factor in assessing damages and that shot could not have come from the gun of both defendants. It was from one or the other only.

It has been held that where a group of persons are on a hunting party, or otherwise engaged in the use of firearms, and two of them are negligent in firing in the direction of a third person who is injured thereby, both of those so firing are liable for the- injury suffered by the third person, although the negligence of only one of them could have caused the injury. (Moore v. Foster, 182 Miss. 15 [180 So. 73]; Oliver v. Miles, 144 Miss. 852 [110 So. 666; 50 A.L.R. 357]; Reyher v. Mayne, 90 Colo. 586 [10 P.2d 1109]; Benson v. Ross, 143 Mich. 452 [106 N.W. 1120, 114 Am.St.Rep. 675].) The same rule has been applied in criminal cases (State v. Newberg, 129 Ore. 564 [278 P. 568, 63 A.L.R. 1225]), and both drivers have been held liable for the negligence of one where they engaged in a racing contest causing an injury to d third person (Saisa v. Lilja, 76 F.2d 380). These cases speak of the action of defendants as being in concert as the ground *85if decision, yet it would seem they are straining that concept and the more reasonable basis appears in Oliver v. Miles, supra. There two persons were hunting together. Both shot at some partridges and in so doing shot across the highway injuring plaintiff who was travelling on it. The court stated they were acting in concert and thus both were liable. The court then stated: “ We think that . . . each is liable for the resulting injury to the boy, although no one can say definitely who actually shot him. To hold otherwise would be to exonerate both from liability, although each was negligent, and the injury resulted from such negligence.” [Emphasis added.] (P. 668 [110 So.'].) It is said in the Restatement: “For harm resulting to a third person from the tortious conduct of another, a person is liable if he . . . (b) knows that the other’s conduct constitutes a breach of duty and gives substantial assistance or encouragement to the other so to conduct himself, or (c) gives substantial assistance to the other in accomplishing a tortious result and his own conduct, separately considered, constitutes a breach of duty to the third person.” (Rest., Torts, § 876(b) (c).) Under subsection (b) the example is given: “A and B are members of a hunting party. Each of them in the presence of the other shoots across a public road at an animal, this being negligent as to persons on the road. A hits the animal. B’s bullet strikes C, a traveler on the road. A is liable to C.” (Rest., Torts, § 876 (b), com., illus. 3.) An illustration given under subsection (c) is the same as above except the factor of both defendants shooting is missing and joint liability is not imposed. It is further said that: “If two forces are actively operating, one because of the actor’s negligence, the other not because of any misconduct on his part, and each of itself is sufficient to bring about harm to another, the actor’s negligence may be held by the jury to be a substantial factor in bringing it about.” (Rest., Torts, § 432.) Dean Wigmore has this to say: “When two or more persons by their acts are possibly the sole cause of a harm, or when two or more acts of the same person are possibly the sole cause, and the plaintiff has introduced evidence that the one of the two persons, or the one of the same person’s two acts, is culpable, then the defendant has the burden of proving that the other person, or his other act, was the sole cause of the harm, (b) ... The real reason for the rule that each joint tortfeasor is responsible for the whole damage is the practical unfairness of denying the injured person redress simply because he cannot prove how *86much damage each did, when it is certain that between them they did all; let them be the ones to apportion it among themselves. Since, then, the difficulty of proof is the reason, the rule should apply whenever the harm has plural causes, and not merely when they acted in conscious concert. ...” (Wigmore, Select Cases on the Law of Torts, § 153.) Similarly Professor Carpenter has said: “[Suppose] the case where A and B independently shoot at C and but one bullet touches C’s body. In such case, such proof as is ordinarily required that either A or B shot C, of course fails. It is suggested that there should be a relaxation of the proof required of the plaintiff . . . where the injury occurs as the result of one where more than one independent force is operating, and it is impossible to determine that the force set in operation by defendant did not in fact constitute a cause of the damage, and where it may have caused the damage, but the plaintiff is unable to establish that it was a cause.” (20 Cal.L.Rev. 406.)

When we consider the relative position of the parties and the results that would flow if plaintiff was required to pin the injury on one of the defendants only, a requirement that the burden of proof on that subject be shifted to defendants becomes manifest. They are both wrongdoers—both negligent toward plaintiff. They brought about a situation where the negligence of one of them injured the plaintiff, hence it should rest with them each to absolve himself if he can. The injured party has been placed by defendants in the unfair position of pointing to which defendant caused the harm. If one can escape the other may also and plaintiff is remediless. Ordinarily defendants are in a far better position to offer evidence' to determine which one caused the injury. This reasoning has recently found favor in this court. In a quite analogous situation this court held that a patient injured while unconscious on an operating table in a hospital could hold all or any of the persons who had any connection with the operation even though he could not select the particular acts by the particular person which led to his disability. (Ybarra v. Spangard, 25 Cal.2d 486 [154 P.2d 687, 162 A.L.R. 1258].) There the court was considering whether the patient could avail himself of res ipsa loquitur, rather than where the burden of proof lay, yet the effect of the decision is that plaintiff has made out a case when he has produced evidence which gives rise to an inference of negligence which was the proximate cause of the injury. It is up to *87defendants to explain the cause of the injury. It was there said: “If the doctrine is to continue to serve a useful purpose, we should not forget that ‘the particular force and justice of the rule, regarded as a presumption throwing upon the party charged the duty of producing evidence, consists in the circumstance that the chief evidence of the true cause, whether culpable or innocent, is practically accessible to him but inaccessible to the injured person.’ ” (P. 490.) Similarly in the instant case plaintiff is not able to establish which of defendants caused his injury.

The foregoing discussion disposes of the authorities cited by defendants such as Kraft v. Smith, 24 Cal.2d 124 [148 P.2d 23], and Hernandez v. Southern California Gas Co., 213 Cal. 384 [2 P.2d 360], stating the general rule that one defendant is not liable for the independent tort of the other defendant, or that ordinarily the plaintiff must show a causal connection between the negligence and the injury. There was an entire lack of such connection in the Hernandez ease and there were not several negligent defendants, one of whom must have caused the injury.

Defendants rely upon Christensen v. Los Angeles Electrical Supply Co., 112 Cal.App. 629 [297 P. 614], holding that a defendant is not liable where he negligently knocks down with his car a pedestrian and a third person then ran over the prostrate person. That involves the question of intervening cause which we do not have here. Moreover it is out of harmony with the current rule on that subject and was properly questioned in Hill v. Peres, 136 Cal.App. 132 [28 P.2d 946] (hearing in this Court denied), and must be deemed disapproved. (See, Mosley v. Arden Farms Co., 26 Cal. 2d 213 [157 P.2d 372, 158 A.L.R. 872]; Sawyer v. Southern California Gas Co., 206 Cal. 366 [274 P. 544]; 2 Cal.Jur. 10-Yr. Supp. Automobiles, § 349; 19 Cal.Jur. 570-572.)

Cases are cited for the proposition that where two or more tort feasors acting independently of each other cause an injury to plaintiff, they are not joint tort feasors and plaintiff must establish the portion of the damage caused by each, even though it is impossible to prove the portion of the injury caused by each. (See, Slater v. Pacific American Oil Co., 212 Cal. 648 [300 P. 31]; Miller v. Highland Ditch Co., 87 Cal. 430 [25 P. 550, 22 Am.St.Rep. 254]; People v. Gold Run D. & M. Co., 66 Cal. 138 [4 P. 1152, 56 Am.Rep. 80]; Wade v. Thorsen, 5 Cal.App.2d 706 [43 P.2d 592]; California O. Co. v. Riverside P. C. Co., 50 Cal.App. 522 [195 P. 694]; *88 City of Oakland v. Pacific Gas & E. Co., 47 Cal.App.2d 444 [118 P.2d 328].) In view of the foregoing discussion it is apparent that defendants in cases like the present one may be treated as liable on the same basis as joint tort feasors, and hence the last-cited cases are distinguishable inasmuch as they involve independent tort feasors.

In addition to that, however, it should be pointed out that the same reasons of policy and justice shift the burden to each of defendants to absolve himself if he can—relieving the wronged person of the duty of apportioning the injury to a particular defendant, apply here where we are concerned with whether plaintiff is required to supply evidence for the apportionment of damages. If defendants are independent tort feasors and thus each liable for the damage caused by him alone, and, at least, where the matter of apportionment is incapable of proof, the innocent wronged party should not be deprived of his right to redress. The wrongdoers should be left to work out between themselves any apportionment. (See, Colonial Ins. Co., v. Industrial Acc. Com., 29 Cal.2d 79 [172 P.2d 884].) Some of the cited cases refer to the difficulty of apportioning the burden of damages between the independent tort feasors, and say that where factually a correct division cannot be made, the trier of fact may make it the best it can, which would be more or less a guess, stressing the factor that the wrongdoers are not in a position to complain of uncertainty. (California O. Co. v. Riverside P. C. Co., supra.)

It is urged that plaintiff now has changed the theory of his case in claiming a concert of action; that he did not plead or prove such concert. From what has been said it is clear that there has been no change in theory. The joint liability, as well as the lack of knowledge as to which defendant was liable, was pleaded and the proof developed the ease under either theory. We have seen that for the reasons of policy discussed herein, the case is based upon the legal proposition that, under the circumstances here presented, each defendant is liable for the whole damage whether they are deemed to be acting in concert or independently.

The judgment is affirmed.

Gibson, C. J., Shenk, J., Edmonds, J., Traynor, J., Schauer, J., and Spence, J., concurred.

Appellant Tice’s petition for a rehearing was denied December 16, 1948.

Opinion

MOSK, J.

This case involves a complex problem both timely and significant: may a plaintiff, injured as the result of a drug administered to her mother during pregnancy, who knows the type of drug involved but cannot identify the manufacturer of the precise product, hold liable for her injuries a maker of a drug produced from an identical formula?

Plaintiff Judith Sindell brought an action against eleven drug companies and Does 1 through 100, on behalf of herself and other women similarly situated. The complaint alleges as follows:

Between 1941 and 1971, defendants were engaged in the business of manufacturing, promoting, and marketing diethylstilbesterol (DES), a drug which is a synthetic compound of the female hormone estrogen. The drug was administered to plaintiff’s mother and the mothers of the class she represents,1 for the purpose of preventing miscarriage. In 1947, the Food and Drug Administration authorized the marketing of DES as a miscarriage preventative, but only on an experimental basis, with a requirement that the drug contain a warning label to that effect.

*594DES may cause cancerous vaginal and cervical growths in the daughters exposed to it before birth, because their mothers took the drug during pregnancy. The form of cancer from which these daughters suffer is known as adenocarcinoma, and it manifests itself after a minimum latent period of 10 or 12 years. It is a fast-spreading and deadly disease, and radical surgery is required to prevent it from spreading. DES also causes adenosis, precancerous vaginal and cervical growths which may spread to other areas of the body. The treatment for adenosis is cauterization, surgery, or cryosurgery. Women who suffer from this condition must be monitored by biopsy or colposcopic examination twice a year, a painful and expensive procedure. Thousands of women whose mothers received DES during pregnancy are unaware of the effects of the drug.

In 1971, the Food and Drug Administration ordered defendants to cease marketing and promoting DES for the purpose of preventing miscarriages, and to warn physicians and the public that the drug should not be used by pregnant women because of the danger to their unborn children.

During the period defendants marketed DES, they knew or should have known that it was a carcinogenic substance, that there was a grave danger after varying periods of latency it would cause cancerous and precancerous growths in the daughters of the mothers who took it, and that it was ineffective to prevent miscarriage. Nevertheless, defendants continued to advertise and market the drug as a miscarriage preventative. They failed to test DES for efficacy and safety; the tests performed by others, upon which they relied, indicated that it was not safe or effective. In violation of the authorization of the Food and Drug Administration, defendants marketed DES on an unlimited basis rather than as an experimental drug, and they failed to warn of its potential danger.2

Because of defendants’ advertised assurances that DES was safe and effective to prevent miscarriage, plaintiff was exposed to the drug prior to her birth. She became aware of the danger from such exposure within one year of the time she filed her complaint. As a result of the DES ingested by her mother, plaintiff developed a malignant bladder *595tumor which was removed by surgery. She suffers from adenosis and must constantly be monitored by biopsy or colposcopy to insure early warning of further malignancy.

The first cause of action alleges that defendants were jointly and individually negligent in that they manufactured, marketed and promoted DES as a safe and efficacious drug to prevent miscarriage, without adequate testing or warning, and without monitoring or reporting its effects.

A separate cause of action alleges that defendants are jointly liable regardless of which particular brand of DES was ingested by plaintiff’s mother because defendants collaborated in marketing, promoting and testing the drug, relied upon each other’s tests, and adhered to an industry-wide safety standard. DES was produced from a common and mutually agreed upon formula as a fungible drug interchangeable with other brands of the same product; defendants knew or should have known that it was customary for doctors to prescribe the drug by its generic rather than its brand name and that pharmacists filled prescriptions from whatever brand of the drug happened to be in stock.

Other causes of action are based upon theories of strict liability, violation of express and implied warranties, false and fraudulent representations, misbranding of drugs in violation of federal law, conspiracy and “lack of consent.”

Each cause of action alleges that defendants are jointly liable because they acted in concert, on the basis of express and implied agreements, and in reliance upon and ratification and exploitation of each other’s testing and marketing methods.

Plaintiff seeks compensatory damages of $1 million and punitive damages of $10 million for herself. For the members of her class, she prays for equitable relief in the form of an order that defendants warn physicians and others of the danger of DES and the necessity of performing certain tests to determine the presence of disease caused by the drug, and that they establish free clinics in California to perform such tests.

Defendants demurred to the complaint. While the complaint did not expressly allege that plaintiff could not identify the manufacturer of the precise drug ingested by her mother, she stated in her points and au*596thorities in opposition to the demurrers filed by some of the defendants that she was unable to make the identification, and the trial court sustained the demurrers of these defendants without leave to amend on the ground that plaintiff did not and stated she could not identify which defendant had manufactured the drug responsible for her injuries. Thereupon, the court dismissed the action.3 This appeal involves only five of ten defendants named in the complaint.4

Plaintiff Maureen Rogers filed a complaint containing allegations generally similar to those made by Sindell. She seeks compensatory and punitive damages on her own behalf, and on behalf of a class described in substantially the same terms as in Sindell’s complaint, as well as equitable relief comparable to that sought by Sindell. The trial court sustained demurrers of E.R. Squibb & Sons, the Upjohn Company, and Rexall Drug Company.5 Subsequent to the dismissal of her action *597against these defendants, Rogers amended the complaint to allege that Eli Lilly and Company, one of the defendants named in her complaint, had manufactured the drug used by her mother. Although Sindell’s action and the present case have been consolidated on appeal, much of the discussion which follows will apply to Rogers only if she does not succeed in establishing that Eli Lilly and Company manufactured the DES taken by her mother. “Plaintiff” as used in this opinion refers to Sindell, and we discuss only the allegations of Sindell’s complaint.

This case is but one of a number filed throughout the country seeking to hold drug manufacturers liable for injuries allegedly resulting from DES prescribed to the plaintiffs’ mothers since 1947.6 According to a note in the Fordham Law Review, estimates of the number of women who took the drug during pregnancy range from IV2 million to 3 million. Hundreds, perhaps thousands, of the daughters of these women suffer from adenocarcinoma, and the incidence of vaginal adenosis among them is 30 to 90 percent. (Comment, DES and a Proposed Theory of Enterprise Liability (1978) 46 Fordham L.Rev. 963, 964-967 [hereafter Fordham Comment].) Most of the cases are still pending. With two exceptions,7 those that have been decided resulted in judgments in favor of the drug company defendants because of the failure of the plaintiffs to identify the manufacturer of the DES prescribed to their mothers.8 The same result was reached in a recent California case. (McCreery v. Eli Lilly & Co. (1978) 87 Cal.App.3d 77, 82-84 [150 Cal.Rptr. 730].) The present action is another attempt to overcome this obstacle to recovery.

We begin with the proposition that, as a general rule, the imposition of liability depends upon a showing by the plaintiff that his or her injuries were caused by the act of the defendant or by an instrumentality under the defendant’s control. The rule applies whether the injury *598resulted from an accidental event (e.g., Shunk v. Bosworth (6th Cir. 1964) 334 F.2d 309) or from the use of a defective product. (E.g., Wetzel v. Eaton Corporation (D.Minn. 1973) 62 F.R.D. 22, 29-30; Garcia v. Joseph Vince Co. (1978) 84 Cal.App.3d 868, 873-875 [148 Cal.Rptr. 843]; and see Annot. collection of cases in 51 A.L.R.3d 1344, 1351; 1 Hursh & Bailey, American Law of Products Liability (2d ed. 1974) p. 125.)

There are, however, exceptions to this rule. Plaintiff’s complaint suggests several bases upon which defendants may be held liable for her injuries even though she cannot demonstrate the name of the manufacturer which produced the DES actually taken by her mother. The first of these theories, classically illustrated by Summers v. Tice (1948) 33 Cal.2d 80 [199 P.2d 1, 5 A.L.R.2d 91], places the burden of proof of causation upon tortious defendants in certain circumstances. The second basis of liability emerging from the complaint is that defendants acted in concert to cause injury to plaintiff. There is a third and novel approach to the problem, sometimes called the theory of “enterprise liability,” but which we prefer to designate by the more accurate term of “industry-wide” liability,9 which might obviate the necessity for identifying the manufacturer of the injury-causing drug. We shall conclude that these doctrines, as previously interpreted, may not be applied to hold defendants liable under the allegations of this complaint. However, we shall propose and adopt a fourth basis for permitting the action to be tried, grounded upon an extension of the Summers doctrine.

I

Plaintiff places primary reliance upon cases which hold that if a party cannot identify which of two or more defendants caused an injury, the burden of proof may shift to the defendants to show that they were not responsible for the harm. This principle is sometimes referred to as the “alternative liability” theory.

The celebrated case of Summers v. Tice, supra, 33 Cal.2d 80, a unanimous opinion of this court, best exemplifies the rule. In Summers, the plaintiff was injured when two hunters negligently shot in his direction. It could not be determined which of them had fired the shot that *599actually caused the injury to the plaintiff’s eye, but both defendants were nevertheless held jointly and severally liable for the whole of the damages. We reasoned that both were wrongdoers, both were negligent toward the plaintiff, and that it would be unfair to require plaintiff to isolate the defendant responsible, because if the one pointed out were to escape liability, the other might also, and the plaintiff-victim would be shorn of any remedy.. In these circumstances, we held, the burden of proof shifted to the defendants, “each to absolve himself if he can.” (Id., p. 86.) We stated that under these or similar circumstances a defendant is ordinarily in a “far better position” to offer evidence to determine whether he or another defendant caused the injury.

In Summers, we relied upon Ybarra v. Spangard (1944) 25 Cal.2d 486 [154 P.2d 687, 162 A.L.R. 1258]. There, the plaintiff was injured while he was unconscious during the course of surgery. He sought damages against several doctors and a nurse who attended him while he was unconscious. We held that it would be unreasonable to require him to identify the particular defendant who had performed the alleged negligent act because he was unconscious at the time of the injury and the defendants exercised control over the instrumentalities which caused the harm. Therefore, under the doctrine of res ipsa loquitur, an inference of negligence arose that defendants were required to meet by explaining their conduct.10

The rule developed in Summers has been embodied in the Restatement of Torts. (Rest.2d Torts, § 433B, subd. (3).)11 Indeed, the Summers facts are used as an illustration (p. 447).

*600Defendants assert that these principles are inapplicable here. First, they insist that a predicate to shifting the burden of proof under Summers-Ybarra is that the defendants must have greater access to information regarding the cause of the injuries than the plaintiff, whereas in the present case the reverse appears.

Plaintiff does not claim that defendants are in a better position than she to identify the manufacturer of the drug taken by her mother or, indeed, that they have the ability to do so at all, but argues, rather, that Summers does not impose such a requirement as a condition to the shifting of the burden of proof. In this respect we believe plaintiff is correct.

In Summers, the circumstances of the accident themselves precluded an explanation of its cause. To be sure, Summers states that defendants are “[ojrdinarily.. .in a far better position to offer evidence to determine which one caused the injury” than a plaintiff (33 Cal.2d 80, at p. 86), but the decision does not determine that this “ordinary” situation was present. Neither the facts nor the language of the opinion indicate that the two defendants, simultaneously shooting in the same direction, were in a better position than the plaintiff to ascertain whose shot caused the injury. As the opinion acknowledges, it was impossible for the trial court to determine whether the shot which entered the plaintiff’s eye came from the gun of one defendant or the other. Nevertheless, burden of proof was shifted to the defendants.

Here, as in Summers, the circumstances of the injury appear to render identification of the manufacturer of the drug ingested by plaintiff’s mother impossible by either plaintiff or defendants, and it cannot reasonably be said that one is in a better position than the other to make the identification. Because many years elapsed between the time the drug was taken and the manifestation of plaintiff’s injuries she, and many other daughters of mothers who took DES, are unable to make such identification.12 Certainly there can be no implication that plaintiff *601is at fault in failing to do so—the event occurred while plaintiff was in útero, a generation ago.13

On the other hand, it cannot be said with assurance that defendants have the means to make the identification. In this connection, they point out that drug manufacturers ordinarily have no direct contact with the patients who take a drug prescribed by their doctors. Defendants sell to wholesalers, who in turn supply the product to physicians and pharmacies. Manufacturers do not maintain records of the persons who take the drugs they produce, and the selection of the medication is made by the physician rather than the manufacturer. Nor do we conclude that the absence of evidence on this subject is due to the fault of defendants. While it is alleged that they produced a defective product with delayed effects and without adequate warnings, the difficulty or impossibility of identification results primarily from the passage of time rather than from their allegedly negligent acts of failing to provide adequate warnings. Thus Haft v. Lone Palm Hotel (1970) 3 Cal.3d 756 [91 Cal.Rptr. 745, 478 P.2d 465], upon which plaintiff relies, is distinguishable.14

It is important to observe, however, that while defendants do not have means superior to plaintiff to identify the maker of the precise drug *602taken by her mother, they may in some instances be able to prove that they did not manufacture the injury-causing substance. In the present case, for example, one of the original defendants was dismissed from the action upon proof that it did not manufacture DES until after plaintiff was born.

Thus we conclude the fact defendants do not have greater access to information that might establish the identity of the manufacturer of the DES which injured plaintiff does not per se prevent application of the Summers rule.

Nevertheless, plaintiff may not prevail in her claim that the Summers rationale should be employed to fix the whole liability for her injuries upon defendants, at least as those principles have previously been applied.15 There is an important difference between the situation involved in Summers and the present case. There, all the parties who were or could have been responsible for the harm to the plaintiff were joined as defendants. Here, by contrast, there are approximately 200 drug companies which made DES, any of which might have manufactured the injury-producing drug.16

Defendants maintain that, while in Summers there was a 50 percent chance that one of the two defendants was responsible for the plaintiff’s injuries, here since any one of 200 companies which manufactured DES *603might have made the product that harmed plaintiff, there is no rational basis upon which to infer that any defendant in this action caused plaintiff’s injuries, nor even a reasonable possibility that they were responsible.17

These arguments are persuasive if we measure the chance that any one of the defendants supplied the injury-causing drug by the number of possible tortfeasors. In such a context, the possibility that any of the five defendants supplied the DES to plaintiff’s mother is so remote that it would be unfair to require each defendant to exonerate itself. There may be a substantial likelihood that none of the five defendants joined in the action made the DES which caused the injury, and that the offending producer not named would escape liability altogether. While we propose, infra, an adaptation of the rule in Summers which will substantially overcome these difficulties, defendants appear to be correct that the rule, as previously applied, cannot relieve plaintiff of the burden of proving the identity of the manufacturer which made the drug causing her injuries.18

II

The second principle upon which plaintiff relies is the so-called “concert of action” theory. Preliminarily, we briefly describe the procedure a drug manufacturer must follow before placing a drug on the market. Under federal law as it read prior to 1962, a new drug was defined as one “not generally recognized as.. .safe.” (§ 102, 76 Stat. 781 (Oct. 10, 1962).) Such a substance could be marketed only if a new drug applica*604tion had been filed with the Food and Drug Administration and had become “effective.”19 If the agency determined that a product was no longer a “new drug,” i.e., that it was “generally recognized as...safe,” (21 U.S.C.A. § 321(p)(l) it could be manufactured by any drug company without submitting an application to the agency. According to defendants, 123 new drug applications for DES had been approved by 1952, and in that year DES was declared not to be a “new drug,” thus allowing any manufacturer to produce it without prior testing and without submitting a new drug application to the Food and Drug Administration.

With this background we consider whether the complaint states a claim based upon “concert of action” among defendants. The elements of this doctrine are prescribed in section 876 of the Restatement Second of Torts. The section provides, “For harm resulting to a third person from the tortious conduct of another, one is subject to liability if he (a) does a tortious act in concert with the other or pursuant to a common design with him, or (b) knows that the other’s conduct constitutes a breach of duty and gives substantial assistance or encouragement to the other so to conduct himself, or (c) gives substantial assistance to the other in accomplishing a tortious result and his own conduct, separately considered, constitutes a breach of duty to the third person.” With respect to this doctrine, Prosser states that “those who, in pursuance of a common plan or design to commit a tortious act, actively take part in it, or further it by cooperation or request, or who lend aid or encouragement to the wrongdoer, or ratify and adopt his acts done for their benefit, are equally liable with him. [1Í] Express agreement is not necessary, and all that is required is that there be a tacit understanding. ...” (Prosser, Law of Torts (4th ed. 1971) § 46, p. 292.)

Plaintiff contends that her complaint states a cause of action under these principles. She alleges that defendants’ wrongful conduct “is the result of planned and concerted action, express and implied agreements, collaboration in, reliance upon, acquiescence in and ratification, exploitation and adoption of each other’s testing, marketing *605methods, lack of warnings... and other acts or omissions...” and that “acting individually and in concert, [defendants] promoted, approved, authorized, acquiesced in, and reaped profits from sales” of DES. These allegations, plaintiff claims, state a “tacit understanding” among defendants to commit a tortious act against her.

In our view, this litany of charges is insufficient to allege a cause of action under the rules stated above. The gravamen of the charge of concert is that defendants failed to adequately test the drug or to give sufficient warning of its dangers and that they relied upon the tests performed by one another and took advantage of each others’ promotional and marketing techniques. These allegations do not amount to a charge that there was a tacit understanding or a common plan among defendants to fail to conduct adequate tests or give sufficient warnings, and that they substantially aided and encouraged one another in these omissions.

The complaint charges also that defendants produced DES from a “common and mutually agreed upon formula,” allowing pharmacists to treat the drug as a “fungible commodity” and to fill prescriptions from whatever brand of DES they had on hand at the time. It is difficult to understand how these allegations can form the basis of a cause of action for wrongful conduct by defendants, acting in concert. The formula for DES is a scientific constant. It is set forth in the United States Pharmacopoeia, and any manufacturer producing that drug must, with exceptions not relevant here, utilize the formula set forth in that compendium. (21 U.S.C.A. § 351(b).)

What the complaint appears to charge is defendants’ parallel or imitative conduct in that they relied upon each others’ testing and promotion methods. But such conduct describes a common practice in industry: a producer avails himself of the experience and methods of others making the same or similar products. Application of the concept of concert of action to this situation would expand the doctrine far beyond its intended scope and would render virtually any manufacturer liable for the defective products of an entire industry, even if it could be demonstrated that the product which caused the injury was not made by the defendant.

None of the cases cited by plaintiff supports a conclusion that defendants may be held liable for concerted tortious acts. They involve *606conduct by a small number of individuals whose actions resulted in a tort against a single plaintiff, usually over a short span of time, and the defendant held liable was either a direct participant in the acts which caused damage,20 or encouraged and assisted the person who directly caused the injuries by participating in a joint activity.21

Orser v. George (1967) 252 Cal.App.2d 660 [60 Cal.Rptr. 708], upon which plaintiff primarily relies, is also distinguishable. There, three hunters negligently shot at a mudhen in decedent’s direction. Two of them shot alternately with the gun which released the bullet resulting in the fatal wound, and the third, using a different gun, fired alternately at the same target, shooting in the same line of fire, perhaps acting tortiously. It was held that there was a possibility the third hunter knew the conduct of the others was tortious toward the decedent and gave them substantial assistance and encouragement, and that it was also possible his conduct, separately considered, was a breach of duty toward decedent. Thus, the granting of summary judgment was reversed as to the third hunter.

The situation in Orser is similar to Agovino v. Kunze, supra, 181 Cal.App.2d 591, in which liability was imposed upon a participant in a drag race, rather than to the facts alleged in the present case. There is no allegation here that each defendant knew the other defendants’ conduct was tortious toward plaintiff, and that they assisted and encouraged one another to inadequately test DES and to provide inadequate warnings. Indeed, it seems dubious whether liability on the concert of action theory can be predicated upon substantial assistance and encouragement given by one alleged tortfeasor to another pursuant to a tacit understanding to fail to perform an act. Thus, there was no concert of action among defendants within the meaning of that doctrine.

*607III

A third theory upon which plaintiff relies is the concept of industry-wide liability, or according to the terminology of the parties, “enterprise liability.” This theory was suggested in Hall v. E. I. Du Pont de Nemours & Co., Inc. (E.D.N.Y. 1972) 345 F.Supp. 353. In that case, plaintiffs were 13 children injured by the explosion of blasting caps in 12 separate incidents which occurred in 10 different states between 1955 and 1959. The defendants were six blasting cap manufacturers, comprising virtually the entire blasting cap industry in the United States, and their trade association. There were, however, a number of Canadian blasting cap manufacturers which could have supplied the caps. The gravamen of the complaint was that the practice of the industry of omitting a warning on individual blasting caps and of failing to take other safety measures created an unreasonable risk of harm, resulting in the plaintiffs’ injuries. The complaint did not identify a particular manufacturer of a cap which caused a particular injury.22

The court reasoned as follows: there was evidence that defendants, acting independently, had adhered to an industry-wide standard with regard to the safety features of blasting caps, that they had in effect delegated some functions of safety investigation and design, such as la-belling, to their trade association, and that there was industry-wide cooperation in the manufacture and design of blasting caps. In these circumstances, the evidence supported a conclusion that all the defen*608dants jointly controlled the risk. Thus, if plaintiffs could establish by a preponderance of the evidence that the caps were manufactured by one of the defendants, the burden of proof as to causation would shift to all the defendants. The court noted that this theory of liability applied to industries composed of a small number of units, and that what would be fair and reasonable with regard to an industry of five or ten producers might be manifestly unreasonable if applied to a decentralized industry composed of countless small producers.23

Plaintiff attempts to state a cause of action under the rationale of Hall. She alleges joint enterprise and collaboration among defendants in the production, marketing, promotion and testing of DES, and “concerted promulgation and adherence to industry-wide testing, safety, warning and efficacy standards” for the drug. We have concluded above that allegations that defendants relied upon one another’s testing and promotion methods do not state a cause of action for concerted conduct to commit a tortious act. Under the theory of industry-wide liability, however, each manufacturer could be liable for all injuries caused by DES by virtue of adherence to an industry-wide standard of safety.

In the Fordham Comment, the industry-wide theory of liability is discussed and refined in the context of its applicability to actions alleging injuries resulting from DES. The author explains causation under that theory as follows, “.. . [T]he industrywide standard becomes itself the cause of plaintiff’s injury, just as defendants’ joint plan is the cause of injury in the traditional concert of action plea. Each defendant’s adherence perpetuates this standard, which results in the manufacture of the particular, unidentifiable injury-producing product. Therefore, each industry member has contributed to plaintiff’s injury.” (Fordham Comment, supra, at p. 997.)

The comment proposes seven requirements for a cause of action based upon industry-wide liability,24 and suggests that if a plaintiff *609proves these elements, the burden of proof of causation should be shifted to the defendants, who may exonerate themselves only by showing that their product could not have caused the injury.25

We decline to apply this theory in the present case. At least 200 manufacturers produced DES; Hall, which involved 6 manufacturers representing the entire blasting cap industry in the United States, cautioned against application of the doctrine espoused therein to a large number of producers. (345 F.Supp. at p. 378.) Moreover, in Hall, the conclusion that the defendants jointly controlled the risk was based upon allegations that they had delegated some functions relating to safety to a trade association. There are no such allegations here, and we have concluded above that plaintiff has failed to allege liability on a concert of action theory.

Equally important, the drug industry is closely regulated by the Food and Drug Administration, which actively controls the testing and manufacture of drugs and the method by which they are marketed, including the contents of warning labels.26 To a considerable degree, therefore, the standards followed by drug manufacturers are suggested or compelled by the government. Adherence to those standards cannot, of course, absolve a manufacturer of liability to which it would otherwise be subject. (Stevens v. Parke, Davis & Co. (1973) 9 Cal.3d 51, 65 [107 *610Cal.Rptr. 45, 507 P.2d 653, 94 A.L.R.3d 1059].) But since the government plays such a pervasive role in formulating the criteria for the testing and marketing of drugs, it would be unfair to impose upon a manufacturer liability for injuries resulting from the use of a drug which it did not supply simply because it followed the standards of the industry.27

IV

If we were confined to the theories of Summers and Hall, we would be constrained to hold that the judgment must be sustained. Should we require that plaintiff identify the manufacturer which supplied the DES used by her mother or that all DES manufacturers be joined in the action, she would effectively be precluded from any recovery. As defendants candidly admit, there is little likelihood that all the manufacturers who made DES at the time in question are still in business or that they are subject to the jurisdiction of the California courts. There are, however, forceful arguments in favor of holding that plaintiff has a cause of action.

In our contemporary complex industrialized society, advances in science and technology create fungible goods which may harm consumers and which cannot be traced to any specific producer. The response of the courts can be either to adhere rigidly to prior doctrine, denying recovery to those injured by such products, or to fashion remedies to meet these changing needs. Just as Justice Tray nor in his landmark concurring opinion in Escola v. Coca Cola Bottling Co. (1944) 24 Cal.2d 453, 467-468 [150 P.2d 436], recognized that in an era of mass production and complex marketing methods the traditional standard of negligence was insufficient to govern the obligations of manufacturer to consumer, so should we acknowledge that some adaptation of the rules of causation and liability may be appropriate in these recurring circumstances. The Restatement comments that modification of the Summers rule may be necessary in a situation like that before us. (See fn. 16, ante.)

The most persuasive reason for finding plaintiff states a cause of action is that advanced in Summers: as between an innocent plaintiff and *611negligent defendants, the latter should bear the cost of the injury. Here, as in Summers, plaintiff is not at fault in failing to provide evidence of causation, and although the absence of such evidence is not attributable to the defendants either, their conduct in marketing a drug the effects of which are delayed for many years played a significant role in creating the unavailability of proof.

From a broader policy standpoint, defendants are better able to bear the cost of injury resulting from the manufacture of a defective product. As was said by Justice Traynor in Escola, “[t]he 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.” (24 Cal.2d p. 462; see also Rest.2d Torts, § 402A, com. c, pp. 349-350.) The manufacturer is in the best position to discover and guard against defects in its products and to warn of harmful effects; thus, holding it liable for defects and failure to warn of harmful effects will provide an incentive to product safety. (Cronin v. J.B.E. Olson Corp. (1972) 8 Cal.3d 121, 129 [104 Cal.Rptr. 433, 501 P.2d 1153]; Beech Aircraft Corp. v. Superior Court (1976) 61 Cal.App.3d 501, 522-523 [132 Cal.Rptr. 541].) These considerations are particularly significant where medication is involved, for the consumer is virtually helpless to protect himself from serious, sometimes permanent, sometimes fatal, injuries caused by deleterious drugs.

Where, as here, all defendants produced a drug from an identical formula and the manufacturer of the DES which caused plaintiff’s injuries cannot be identified through no fault of plaintiff, a modification of the rule of Summers is warranted. As we have seen, an undiluted Summers rationale is inappropriate to shift the burden of proof of causation to defendants because if we measure the chance that any particular manufacturer supplied the injury-causing product by the number of producers of DES, there is a possibility that none of the five defendants in this case produced the offending substance and that the responsible manufacturer, not named in the action, will escape liability.

But we approach the issue of causation from a different perspective: we hold it to be reasonable in the present context to measure the likelihood that any of the defendants supplied the product which allegedly injured plaintiff by the percentage which the DES sold by each of them for the purpose of preventing miscarriage bears to the entire production *612of the drug sold by all for that purpose. Plaintiff asserts in her briefs that Eli Lilly and Company and five or six other companies produced 90 percent of the DES marketed. If at trial this is established to be the fact, then there is a corresponding likelihood that this comparative handful of producers manufactured the DES which caused plaintiff’s injuries, and only a 10 percent likelihood that the offending producer would escape liability.28

If plaintiff joins in the action the manufacturers of a substantial share of the DES which her mother might have taken, the injustice of shifting the burden of proof to defendants to demonstrate that they could not have made the substance which injured plaintiff is significantly diminished. While 75 to 80 percent of the market is suggested as the requirement by the Fordham Comment (at p. 996), we hold only that a substantial percentage is required.

The presence in the action of a substantial share of the appropriate market also provides a ready means to apportion damages among the defendants. Each defendant will be held liable for the proportion of the judgment represented by its share of that market unless it demonstrates that it could not have made the product which caused plaintiff’s injuries. In the present case, as we have seen, one DES manufacturer was dismissed from the action upon filing a declaration that it had not manufactured DES until after plaintiff was born. Once plaintiff has met her burden of joining the required defendants, they in turn may cross-complain against other DES manufacturers, not joined in the action, which they can allege might have supplied the injury-causing product.

Under this approach, each manufacturer’s liability would approximate its responsibility for the injuries caused by its own products. Some minor discrepancy in the correlation between market share and liability is inevitable; therefore, a defendant may be held liable for a somewhat different percentage of the damage than its share of the appropriate *613market would justify. It is probably impossible, with the passage of time, to determine market share with mathematical exactitude. But just as a jury cannot be expected to determine the precise relationship between fault and liability in applying the doctrine of comparative fault (Li v. Yellow Cab Co. (1975) 13 Cal.3d 804 [119 Cal.Rptr. 858, 532 P.2d 1226, 78 A.L.R.3d 393]) or partial indemnity (American Motorcycle Assn. v. Superior Court (1978) 20 Cal.3d 578 [146 Cal.Rptr. 182, 578 P.2d 899]), the difficulty of apportioning damages among the defendant producers in exact relation to their market share does not seriously militate against the rule we adopt. As we said in Summers with regard to the liability of independent tortfeasors, where a correct division of liability cannot be made “the trier of fact may make it the best it can.” (33 Cal.2d at p. 88.)

We are not unmindful of the practical problems involved in defining the market and determining market share,29 but these are largely matters of proof which properly cannot be determined at the pleading stage of these proceedings. Defendants urge that it would be both unfair and contrary to public policy to hold them liable for plaintiffs injuries in the absence of proof that one of them supplied the drug responsible for the damage. Most of their arguments, however, are based upon the assumption that one manufacturer would be held responsible for the products of another or for those of all other manufacturers if plaintiff ultimately prevails. But under the rule we adopt, each manufacturer’s liability for an injury would be approximately equivalent to the damage caused by the DES it manufactured.30

The judgments are reversed.

Bird, C. J., Newman, J., and White, J.,* concurred.

*614RICHARDSON, J.

I respectfully dissent. In these consolidated cases the majority adopts a wholly new theory which contains these ingredients: The plaintiffs were not alive at the time of the commission of the tortious acts. They sue a generation later. They are permitted to receive substantial damages from multiple defendants without any proof that any defendant caused or even probably caused plaintiffs’ injuries.

Although the majority purports to change only the required burden of proof by shifting it from plaintiffs to defendants, the effect of its holding is to guarantee that plaintiffs will prevail on the causation issue because defendants are no more capable of disproving factual causation than plaintiffs are of proving it. “Market share” liability thus represents a new high water mark in tort law. The ramifications seem almost limitless, a fact which prompted one recent commentator, in criticizing a substantially identical theory, to conclude that “Elimination of the burden of proof as to identification [of the manufacturer whose drug injured plaintiff] would impose a liability which would exceed absolute liability.” (Coggins, Industry-Wide Liability (1979) 13 Suffolk L.Rev. 980, 998, fn. omitted; see also, pp. 1000-1001.) In my view, the majority’s departure from traditional tort doctrine is unwise.

The applicable principles of causation are very well established. A leading torts scholar, Dean Prosser, has authoritatively put it this way: “An essential element of the plaintiff’s cause of action for negligence, or for that matter for any other tort, is that there be some reasonable connection between the act or omission of the defendant and the damage which the plaintiff has suffered.” (Prosser, Torts (4th ed. 1971) § 41, p. 236, italics added.) With particular reference to the matter before us, and in the context of products liability, the requirement of a causation element has been recognized as equally fundamental. “It is clear that any holding that a producer, manufacturer, seller, or a person in a similar position, is liable for injury caused by a particular product, must necessarily be predicated upon proof that the product in question was one for whose condition the defendant was in some way responsible. Thus, for example, if recovery is sought from a manufacturer, it must be shown that he actually was the manufacturer of the product which caused the injury;...” (1 Hursh & Bailey, American Law of Products Liability (2d ed. 1974) § 1:41, p. 125, italics added; accord, Prosser, supra, § 103, at pp. 671-672; 2 Dooley, Modern Tort Law (1977) § 32.03, p. 243.) Indeed, an inability to prove this causal link between defendant’s conduct and plaintiffs injury has proven fatal in prior cases *615brought against manufacturers of DES by persons who were situated in positions identical to those of plaintiffs herein. (See McCreery v. Eli Lilly & Co. (1978) 87 Cal.App.3d 77, 82 [150 Cal.Rptr. 730]; Gray v. United States (S.D.Tex. 1978) 445 F.Supp. 337, 338.)

The majority now expressly abandons the foregoing traditional requirement of some causal connection between defendants’ act and plaintiffs’ injury in the creation of its new modified industry-wide tort. Conceptually, the doctrine of absolute liability which heretofore in negligence law has substituted only for the requirement of a breach of defendant’s duty of care, under the majority’s hand now subsumes the additional necessity of a causal relationship.

According to the majority, in the present case plaintiffs have openly conceded that they are unable to identify the particular entity which manufactured the drug consumed by their mothers. In fact, plaintiffs have joined only five of the approximately two hundred drug companies which manufactured DES. Thus, the case constitutes far more than a mere factual variant upon the theme composed in Summers v. Tice (1948) 33 Cal.2d 80 [199 P.2d 1], wherein plaintiff joined as codefendants the only two persons who could have injured him. As the majority must acknowledge, our Summers rule applies only to cases in which “... it is proved that harm has been caused to the plaintiff by... one of [the named defendants], but there is uncertainty as to which one has caused it,... ” (Rest.2d Torts, § 433B, subd. (3).) In the present case, in stark contrast, it remains wholly speculative and conjectural whether any of the five named defendants actually caused plaintiffs’ injuries.

The fact that plaintiffs cannot tie defendants to the injury-producing drug does not trouble the majority for it declares that the Summers requirement of proof of actual causation by a named defendant is satisfied by a joinder of those defendants who have together manufactured “a substantial percentage” of the DES which has been marketed. Notably lacking from the majority’s expression of its new rule, unfortunately, is any definition or guidance as to what should constitute a “substantial” share of the relevant market. The issue is entirely open-ended and the answer, presumably, is anyone’s guess.

Much more significant, however, is the consequence of this unprecedented extension of liability. Recovery is permitted from a handful of defendants each of whom individually may account for a comparatively *616small share of the relevant market, so long as the aggregate business of those who have been sued is deemed “substantial.” In other words, a particular defendant may be held proportionately liable even though mathematically it is much more likely than not that it played no role whatever in causing plaintiffs’ injuries. Plaintiffs have strikingly capsulated their reasoning by insisting “.. . that while one manufacturer’s product may not have injured a particular plaintiff, we can assume that it injured a different plaintiff and all we are talking about is a mere matching of plaintiffs and defendants.” (Counsel’s letter (Oct. 16, 1979) p. 3.) In adopting the foregoing rationale the majority rejects over 100 years of tort law which required that before tort liability was imposed a “matching” of defendant’s conduct and plaintiff’s injury was absolutely essential. Furthermore, in bestowing on plaintiffs this new largess the majority sprinkles the rain of liability upon all the joined defendants alike—those who may be tortfeasors and those who may have had nothing at all to do with plaintiffs’ injury—and an added bonus is conferred. Plaintiffs are free to pick and choose their targets.

The “market share” thesis may be paraphrased. Plaintiffs have been hurt by someone who made DES. Because of the lapse of time no one can prove who made it. Perhaps it was not the named defendants who made it, but they did make some. Although DES was apparently safe at the time it was used, it was subsequently proven unsafe as to some daughters of some users. Plaintiffs have suffered injury and defendants are wealthy. There should be a remedy. Strict products liability is unavailable because the element of causation is lacking. Strike that requirement and label what remains “alternative” liability, “industry-wide” liability, or “market share” liability, proving thereby that if you hit the square peg hard and often enough the round holes will really become square, although you may splinter the board in the process.

The foregoing result is directly contrary to long established tort principles. Once again, in the words of Dean Prosser, the applicable rule is: “[Plaintiff] must introduce evidence which affords a reasonable basis for the conclusion that it is more likely than not that the conduct of the defendant was a substantial factor in bringing about the result. A mere possibility of such causation is not enough, and when the matter remains one of pure speculation or conjecture, or the probabilities are at best evenly balanced, it becomes the duty of the court to direct a verdict for the defendant.” (Prosser, supra, § 41, at p. 241, italics added, fns. *617omitted.) Under the majority’s new reasoning, however, a defendant is fair game if it happens to be engaged in a similar business and causation is possible, even though remote.

In passing, I note the majority’s dubious use of market share data. It is perfectly proper to use such information to assist in proving, circumstantially, that a particular defendant probably caused plaintiffs’ injuries. Circumstantial evidence may be used as a basis for proving the requisite probable causation. (Id., at p. 242.) The majority, however, authorizes the use of such evidence for an entirely different purpose, namely, to impose and allocate liability among multiple defendants only one of whom may have produced the drug which injured plaintiffs. Because this use of market share evidence does not implicate any particular defendant, I believe such data are entirely irrelevant and inadmissible, and that the majority errs in such use. In the absence of some statutory authority there is no legal basis for such use.

Although seeming to acknowledge that imposition of liability upon defendants who probably did not cause plaintiffs’ injuries is unfair, the majority justifies this inequity on the ground that “each manufacturer’s liability for an injury would be approximately equivalent to the damages caused by the DES it manufactured.” (Ante, p. 613.) In other words, because each defendant’s liability is proportionate to its market share, supposedly “each manufacturer’s liability would approximate its responsibility for the injuries caused by his own products.” (Ante, p. 612.) The majority dodges the “practical problems” thereby presented, choosing to describe them as “matters of proof.” However, the difficulties, in my view, are not so easily ducked, for they relate not to evidentiary matters but to the fundamental question of liability itself.

Additionally, it is readily apparent that “market share” liability will fall unevenly and disproportionately upon those manufacturers who are amenable to suit in California. On the assumption that no other state will adopt so radical a departure from traditional tort principles, it may be concluded that under the majority’s reasoning those defendants who are brought to trial in this state will bear effective joint responsibility for 100 percent of plaintiffs’ injuries despite the fact that their “substantial” aggregate market share may be considerably less. This undeniable fact forces the majority to concede that, “a defendant may be held liable for a somewhat different percentage of the damage than its share of the appropriate market would justify.” (Ante, pp. 612-613.) *618With due deference, I suggest that the complete unfairness of such a result in a case involving only five of two hundred manufacturers is readily manifest.

Furthermore, several other important policy considerations persuade me that the majority holding is both inequitable and improper. The injustice inherent in the majority’s new theory of liability is compounded by the fact that plaintiffs who use it are treated far more favorably than are the plaintiffs in routine tort actions. In most tort cases plaintiff knows the identity of the person who has caused his injuries. In such a case, plaintiff, of course, has no option to seek recovery from an entire industry or a “substantial” segment thereof, but in the usual instance can recover, if at all, only from the particular defendant causing injury. Such a defendant may or may not be either solvent or amenable to process. Plaintiff in the ordinary tort case must take a chance that defendant can be reached and can respond financially. On what principle should those plaintiffs who wholly fail to prove any causation, an essential element of the traditional tort cause of action, be rewarded by being offered both a wider selection of potential defendants and a greater opportunity for recovery?

The majority attempts to justify its new liability on the ground that defendants herein are “better able to bear the cost of injury resulting from the manufacture of a defective product.” (Ante, p. 611.) This “deep pocket” theory of liability, fastening liability on defendants presumably because they are rich, has understandable popular appeal and might be tolerable in a case disclosing substantially stronger evidence of causation than herein appears. But as a general proposition, a defendant’s wealth is an unreliable indicator of fault, and should play no part, at least consciously, in the legal analysis of the problem. In the absence of proof that a particular defendant caused or at least probably caused plaintiff’s injuries, a defendant’s ability to bear the cost thereof is no more pertinent to the underlying issue of liability than its “substantial” share of the relevant market. A system priding itself on “equal justice under law” does not flower when the liability as well as the damage aspect of a tort action is determined by a defendant’s wealth. The inevitable consequence of such a result is to create and perpetuate two rules of law—one applicable to wealthy defendants, and another standard pertaining to defendants who are poor or who have modest means. Moreover, considerable doubts have been expressed regarding the ability of the drug industry, and especially its smaller members, to bear the substantial economic costs (from both damage awards and *619high insurance premiums) inherent in imposing an industry-wide liability. (See Coggins, supra, 13 Suffolk L.Rev. at pp. 1003-1006, 1010-1011.)

An important and substantial countervailing public policy in defendants’ favor was very recently expressed in a similar DES case, McCreery v. Eli Lilly & Co., supra, 87 Cal.App.3d 77, 86-87. Although the majority herein impliedly rejects the appellate court’s holding, in my opinion pertinent language of the McCreery court, based upon the Restatement of Torts and bearing on the majority’s “market share” theory, is well worth repeating: “Application of the comments to the Restatement Second of Torts, section 402A, to this situation compels a rejection of the imposition of liability. As the comment states, ‘... It is also true in particular of many new or experimental drugs as to which, because of lack of time and opportunity for sufficient medical experience, there can be no assurance of safety, or perhaps even of purity of ingredients, but such experience as there is justifies the marketing and use of the drug notwithstanding a medically recognizable risk. The seller of such products, again, with the qualification that they are properly prepared and marketed, and proper warning is given, where the situation calls for it, is not to be held to strict liability for unfortunate consequences attending their use, merely because he has undertaken to supply the public with an apparently useful and desirable product, attended with a known but apparently reasonable risk.’ (Rest. 2d Torts, § 402A, com. k.) This section implicitly recognizes the social policy behind the development of new pharmaceutical preparations. As one commentator states, ‘[t]he social and economic benefits from mobilizing the industry’s resources in the war against disease and in reducing the costs of medical care are potentially enormous. The development of new drugs in the last three decades has already resulted in great social benefits. The potential gains from further advances remain large. To risk such gains is unwise. Our major objective should be to encourage a continued high level of industry investment in pharmaceutical R & D [research and development].’ (Schwartzman, The Expected Return from Pharmaceutical Research: Sources of New Drugs and the Profitability of R & D Investment (1975) p. 54.)” (McCreery v. Eli Lilly & Co., supra, 87 Cal.App.3d 77, 86-87, italics added; see also Coggins, supra, 13 Suffolk L.Rev. at p. 1004.)

In the present case the majority imposes liability more than 20 years after ingestion of drugs which at the time they were used, after careful *620testing, had the full approval of the United States Food and Drug Administration. It seems to me that liability in the manner created by the majority must inevitably inhibit, if not the research or development, at least the dissemination of new pharmaceutical drugs. Such a result, as explained by the Restatement, is wholly inconsistent with traditional tort theory.

I also suggest that imposition of so sweeping a liability may well prove to be extremely shortsighted from the standpoint of broad social policy. Who is to say whether, and at what time and in what form, the drug industry upon which the majority now fastens this blanket liability, may develop a miracle drug critical to the diagnosis, treatment, or, indeed, cure of the very disease in question? It is counterproductive to inflict civil damages upon all manufacturers for the side effects and medical complications which surface in the children of the users a generation after ingestion of the drugs, particularly when, at the time of their use, the drugs met every fair test and medical standard then available and applicable. Such a result requires of the pharmaceutical industry a foresight, prescience and anticipation far beyond the most exacting standards of the relevant scientific disciplines. In effect, the majority requires the pharmaceutical research laboratory to install a piece of new equipment—the psychic’s crystal ball.

I am not unmindful of the serious medical consequences of plaintiffs’ injuries, and the equally serious implications to the class which she purports to represent. In balancing the various policy considerations, however, I also observe that the incidence of vaginal cancer among “DES daughters” has been variously estimated at one-tenth of 1 percent to four-tenths of 1 percent. (13 Suffolk L.Rev., supra, p. 999, fn. 92.) These facts raise some penetrating questions. Ninety-nine plus percent of “DES daughters” have never developed cancer. Must a drug manufacturer to escape this blanket liability wait for a generation of testing before it may disseminate drugs similar to DES? If a drug has beneficial purposes for the majority of users but harmful side-effects are later revealed for a small fraction of consumers, will the manufacturer be absolutely liable? If adverse medical consequences, wholly unknown to the most careful and meticulous of present scientists, surface in two or three generations, will similar liability be imposed? In my opinion, common sense and reality combine to warn that a “market share” theory goes too far. Legally, it expects too much.

*621I believe that the scales of justice tip against imposition of this new liability because of the foregoing elements of unfairness to some defendants who may have had nothing whatever to do with causing any injury, the unwarranted preference created for this particular class of plaintiffs, the violence done to traditional tort principles by the drastic expansion of liability proposed, the injury threatened to the public interest in continued unrestricted basic medical research as stressed by the Restatement, and the other reasons heretofore expressed.

The majority’s decision effectively makes the entire drug industry (or at least its California members) an insurer of all injuries attributable to defective drugs of uncertain or unprovable origin, including those injuries manifesting themselves a generation later, and regardless of whether particular defendants had any part whatever in causing the claimed injury. Respectfully, I think this is unreasonable overreaction for the purpose of achieving what is perceived to be a socially satisfying result.

Finally, I am disturbed by the broad and ominous ramifications of the majority’s holding. The law review comment, which is the wellspring of the majority’s new theory, conceding the widespread consequences of industry-wide liability, openly acknowledges that “The DES cases are only the tip of an iceberg.” (Comment, DES and a Proposed Theory of Enterprise Liability (1978) 46 Fordham L.Rev. 963, 1007.) Although the pharmaceutical drug industry may be the first target of this new sanction, the majority’s reasoning has equally threatening application to many other areas of business and commercial activities.

Given the grave and sweeping economic, social, and medical effects of “market share” liability, the policy decision to introduce and define it should rest not with us, but with the Legislature which is currently considering not only major statutory reform of California product liability law in general, but the DES problem in particular. (See Sen. Bill No. 1392 (1979-1980 Reg. Sess.), which would establish and appropriate funds for the education, identification, and screening of persons exposed to DES, and would prohibit health care and hospital service plans from excluding or limiting coverage to persons exposed to DES.) An alternative proposal for administrative compensation, described as “a limited version of no-fault products liability” has been suggested by one commentator. (Coggins, supra, 13 Suffolk L.Rev. at pp. 1019-1021.) Compensation under such a plan would be awarded by an administra*622tive tribunal from funds collected “via a tax paid by all manufacturers.” (P. 1020, fn. omitted.) In any event, the problem invites a legislative rather than an attempted judicial solution.

I would affirm the judgments of dismissal.

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

Respondents’ petitions for a rehearing were denied May 7, 1980. Tobriner, J., did not participate therein. White, J.,* participated therein. Clark, J., Richardson, J., and Manuel, J., were of the opinion that the petitions should be granted.

OPINION OF THE COURT

Emily Pines, J.

Defendants, The Dow Chemical Company (Dow), sued in this case as a manufacturer of perchloroethylene (perc or PCE), and R.R. Street & Co. (Street), sued as an exclusive distributor of perc and as a manufacturer of a perc-containing product, move to dismiss the plaintiff Suffolk County Water Authority’s (SCWA) complaint, as amended, pursuant to CPLR 3211 (a) (7) or for alternative relief under CPLR 3211 (c). The SCWA opposes the motion.

The basis for the current motion lies in the admitted inability of the SCWA to identify each precise defendant whose allegedly defective product injured the plaintiff and how the conduct of such party was the “cause-in-fact” of such injury. In its now *571amended complaint, the Suffolk County Water Authority asserts what is known as “market share liability” with regard to the chemical manufacturing defendants in this case based upon, inter alia, the plaintiff’s assertion that identification of the exact defendant whose product caused the environmental property damage alleged is impossible.

Defendants contend that the use of the market share collective liability concept has been approved in only one instance in the State of New York — in the case of Hymowitz v Eli Lilly & Co. (73 NY2d 487 [1989]). As set forth by Dow and Street, the Court of Appeals in Hymowitz permitted the use of market share liability in a unique instance where injured plaintiffs were unable to prove which manufacturer of DES actually made the product taken by their mothers and allowed several liability to be imposed on all market participants according to the share each contributed to DES sold for use during pregnancy. However, these defendants assert that such was not the only basis for the unique holding in Hymowitz. Rather, they state that the Court of Appeals cautioned: “[t]he DES situation is a singular case, with manufacturers acting in a parallel manner to produce an identical, generically marketed product, which causes injury many years later, and which has evoked a legislative response reviving previously barred actions.” (Hymowitz at 508.) Moreover, defendants assert that in Hymowitz, the manufacturers only contributed to the risk involved as the pill itself was the only causative agent, and no issues of fact were presented to the court in that case regarding product misuse by patients, physicians or pharmacists. In a later case, the Court of Appeals, therefore, as per the defendants, rejected use of the market share approach in Hamilton v Beretta U.S.A. Corp. (96 NY2d 222 [2001]). The Court denied application of the approach in that case brought by shooting victims against handgun manufacturers stating that

“[e]ach manufacturer engaged in different marketing activities that allegedly contributed to the illegal handgun market in different ways and to a different extent. Plaintiffs made no attempt to establish the relative fault of each manufacturer, but instead sought to hold them all liable based simply on market share. . . .

“Defendants engaged in widely-varied conduct creating varied risks. Thus, a manufacturer’s share of the national handgun market does not necessar*572ily correspond to the amount of risk created by its alleged tortious conduct. No case has applied the market share theory ... to such varied conduct and wisely so.” (Hamilton at 241.)

Thus, the defendants argue that the SCWA’s claims in its amended complaint are not limited to manufacture and sale of PCE to dry cleaners, but, also include allegations of improper marketing and negligent failure to provide appropriate instructions and warnings regarding the use of perc as well as its disposal — actions which are not uniform in the manner of manufacture of DES. Moreover, defendants state that plaintiff has now asserted liability by these manufacturers, which have sold and marketed their product to differing industries, opening the issue of differences among the various means and methods by which perc contamination could occur.

According to defendants, the most significant distinction between this case and Hymowitz lies in the fact that it is undisputed that control of risk of perc contamination extends well beyond any conduct of manufacturers to include: (1) independent distributors responsible for dissemination of product literature and safe delivery of the chemical; (2) manufacturers of dry cleaning machines designed to use perc products; (3) property owners who exercise control over activities on their property; (4) dry cleaners who operate the equipment and dispose of PCE; and (5) myriad other users of PCE such as industrial facilities and individual homeowners who use it to clean septic tanks. The defendants cite Brenner v American Cyanamid Co. (263 AD2d 165 [4th Dept 1999]), where the Court rejected the market share approach in a case against manufacturers of lead pigment used in paints. The Court, in Brenner, as per defendants herein, distinguished causation of harm from lead paint where the control of risk was shared among the pigment manufacturers and paint manufacturers, as well as owners and landlords of residential properties, who controlled risk through maintenance practices:

“A fourth factor considered by the Court in Hymowitz was the exclusive control of DES manufacturers over any risk produced by their product. . . . [0]wners and landlords of residences had control of some of the risk posed by lead-based paint, which becomes hazardous when it peels and flakes and is then ingested or the dust inhaled. Owners and landlords could control such risk by proper maintenance of their property. Furthermore, manufactur*573ers of DES intended that their product be ingested by pregnant women to prevent miscarriages. In contrast, white lead carbonate or lead-based paint is not intended for ingestion and obviously was not marketed for such a use.” (.Brenner at 172-173.)

Thus, as per the holding in Brenner, defendants assert that this court is indeed bound to reject the market share approach by SCWA.

Defendants point to more areas distinguishing the current case from Hymowitz. These include the assertion that market sales of perc cannot be apportioned as with DES by identifying uniform conduct over a discrete period of time, as the SCWA has failed to identify when the contamination occurred. In addition, there has been no legislative signal to provide a tort remedy as there was in the DES situation. Further, defendants assert that as in Hamilton, the SCWA’s claims against PCE manufacturers are not limited to the simple manufacture of goods, but also include negligent failure to provide appropriate warnings regarding the use of the chemical.

Finally, the moving defendants argue that even if the court were inclined to apply the market share approach in this case, the SCWA has failed to establish the very first condition precedent — i.e., that following exhaustive discovery, conventional proof of product identification is impossible. In this regard, defendants note that the plaintiff has failed to notice the depositions of many dry cleaners or distributors nor conducted interviews of the same. In this vein, the defendants set forth that even if discovery at this stage would lead to no evidence of manufacturer identification, that the SCWA failed to investigate and track down sources of contamination (including dry cleaners, distributors and manufacturers) for decades since its 1980 annual report following a presentation to the Suffolk County Legislature concerning PCE contamination in the groundwater and its 1994 article by a SCWA engineer identifying dry cleaners as one of the sources of PCE contamination.

Plaintiff, SCWA, opposes the motion, setting forth that the Court of Appeals in the Hymowitz and Hamilton decisions never stated that market share liability was to be limited solely to cases involving DES. Rather, plaintiff asserts that where the identification of the manufacturer of a defective product is generally impossible, a plaintiff need not identify the particular defendant that caused the injury. However, in such cases, the plaintiff must still make a prima facie case on all other ele*574ments of the alleged tort. Even in Hamilton, which rejected application of the market share approach to liability, according to plaintiff, the Court of Appeals did not state that it was so holding based upon the fact that handguns were not DES. Rather, as per SCWA, the Court conducted a factual analysis and determined that market share could not apply because:

“[ujnlike DES, guns are not identical, fungible products. Significantly, it is often possible to identify the caliber and manufacturer of the handgun that caused injury to a particular plaintiff. Even more importantly — given the negligent marketing theory on which plaintiffs tried this case — plaintiffs have never asserted that the manufacturers’ marketing techniques were uniform.” (Hamilton at 240-241.)

In the case at bar, SCWA argues that PCE remains a fungible product, is entirely interchangeable, and the defendants, through extensive discovery, have themselves not identified any means to distinguish the product within a dry cleaning machine, released to the aquifer and traveling through the soil. Plaintiff also sets forth that the number of chemical manufacturers is small and all of the same have been named in plaintiffs original complaint.

SCWA also distinguishes this case from Hamilton because its claim is one of defective design. It states that its allegation is essentially that perc was defective the moment it left the manufacturer’s control, and that it did not become dangerous only through the acts of third parties, such as is the case with the handguns. Rather, perc is assertedly defective as designed and cannot be used in any manner without its release into the environment. Moreover, according to plaintiff, the chemical defendants were well aware of the release of perc during normal use and handling by distributors and dry cleaners. The plaintiff supports this assertion by submission of one of its experts, Bruce Dale, who states dry cleaning was designed with the expectation that PCE-containing waste would be disposed of through the drain and that all knew this.

In further support of this claim, plaintiff asserts that whether warnings varied, as claimed by defendants, is irrelevant to the question whether the product itself varied among the chemical defendants — plaintiff has asserted that the product itself was defectively designed; that it is fungible, interchangeable and generic.

In addition, the plaintiff distinguishes its claims from those set forth in Brenner. It asserts that in Brenner, the plaintiffs *575sued the manufacturers of lead carbonate alleging that their house was painted with paint containing such product; however, the existence of other lead compounds and their presence in some but not all lead paints led the Fourth Department to conclude that, unlike DES, lead paint is not a fungible product that remained unchanged from manufacture to ingestion. (Brenner at 172.) The plaintiff in the case at bar has stated that PCE did not change from the point of manufacture and sale to the point of injury — here, the contamination of one of the SCWA wells. Moreover, although Brenner also refers to the risk of harm by contributing third parties, plaintiff argues that there has been no showing by defendants that any nonparty herein contributed to the risk of harm presented by the design itself of perc.

Plaintiff submits admissions by chemical defendants obtained during the course of discovery, in which they stated that PCE is generic and fungible. As set forth in the deposition of an employee of Street responsible for the company’s nationwide solvent business between 1974 and 2011: “[d]ry cleaners typically didn’t know what perc they were using. They may know who they purchased it from in terms of the distributor they purchased it from, but they wouldn’t know whose product it was.”

Plaintiff referred to additional testimony of defendants to the effect that when one manufacturer’s PCE was introduced into the dry cleaner’s system, it would be commingled with a product produced by another manufacturer, rendering identification basically impossible. The fact that one manufacturer’s PCE is interchangeable with that of another manufacturer was also assertedly admitted in the interrogatory responses of chemical manufacturer defendant, Legacy Vulcan Corporation. This was assertedly reiterated by discovery from dry cleaners. Again, plaintiffs expert opined that “[i]t is impossible to distinguish between perc made by one manufacturer versus perc made by another manufacturer.”

SCWA argues that other factors contribute to why a sufficient claim has been made in the case at bar for a market share approach to avoid dismissal under CPLR 3211 (a). These include the assertion of a long latency period, citing the opinion of plaintiffs hydrologist that PCE moves at a pace of one to two feet per day through the aquifer underlying Suffolk County. Plaintiff also points to what it terms exhaustive discovery resulting in an inability to determine which defendants’ products *576caused the harm asserted herein. Thus, out of 88 subpoenas served on dry cleaners in Suffolk County, only one was able to identify the manufacturing source of its perc; serial owners as well as poor document retention preclude in many instances the ability to obtain documentary evidence pertaining to operations at locations in the 1980s and 1990s; at some locations, there have been as many as four establishments. Plaintiff has also assertedly attempted to obtain information by serving subpoenas on 24 distributors, some of whom have ceased doing business, some of whom have refused to reply, some of whom have stated they have no records, and others that have verbally spoken with one of plaintiffs experts stating that they have no documents reflecting sales or deliveries of PCE to dry cleaners in Suffolk County. Further, of the actual depositions SCWA has taken of dry cleaning operators, they were essentially unable to identify the manufacturers of the PCE and those that had invoices from distributors produced documents which again lacked any manufacturer identification. Thus, the plaintiff sets forth that it has conducted exhaustive discovery and such contradicts the defendants’ claim that it can somehow discover what it has not been able to uncover thus far. Plaintiff also avers that its expert estimates that 75-80% of all PCE releases to the environment come from dry cleaning; that the chemical defendants named in this case produced all the PCE found in Suffolk County and indeed represent over 90% of the market for PCE in the United States.

Finally, the plaintiff argues that the assertion by defendants that other parties may have contributed to PCE contamination of the Suffolk County wells does not prevent the defendants from demonstrating to the trier of fact that other causes contributed to such property damage nor that such party’s conduct constitutes either an intervening or superseding cause cutting the causal connection with regard to a particular well. In this vein, plaintiff argues that under New York law, if an intervening act was a foreseeable consequence of the defendant’s negligence, that defendant will still be held liable.

Defendants assert, in reply, that plaintiffs description of its own allegedly extensive discovery only adds support to their current motion. Thus, they set forth that the Water Authority’s description of the “Carillon Cleaners” site problem demonstrates that contributors to the harm included the dry cleaner operator, the PCE distributor, the manufacturer of dry cleaning equipment and those responsible for site cleanup — all in addi*577tion to the chemical manufacturers. Thus, defendants argue that the PCE case cannot be based upon a theory of market share where it simply cannot accurately apportion all fault that contributed to the risk.

Defendants also opine that the plaintiff cannot escape the relevance of differences among the PCE manufacturer’s various product warnings simply by dropping its failure to warn cause of action. It claims, rather, that this supports its theory that to allocate fault, the contents of various warnings must be determined.

Defendants set forth that the Brenner case has been recently followed by S.F. v Archer-Daniels-Midland Co. (2014 WL 1600414, 2014 US Dist LEXIS 55195 [WD NY, Apr. 21, 2014, No. 13-CV-634S]), where the court rejected the market share doctrine to a product liability claim against manufacturers of high fructose corn syrup, stating, inter alia, that defendant manufacturers did “not have exclusive control of the risk” associated with the product. (2014 WL 1600414, *6, 2014 US Dist LEXIS 55195, *17.) In this vein, defendants point to the opinions from the SCWA’s experts demonstrating that diy cleaning equipment manufacturers and suppliers contribute to the risk of PCE contamination, and from Suffolk County inspectors setting forth that dry cleaning establishment owners dumped waste down the floor drain because they didn’t want to pay for proper removal.

Based on the above, defendants ask this court to dismiss the complaint in toto, as the plaintiff has clearly asserted that it cannot identify which chemical company produced the precise PCE in any of the subject contaminated wells. In the alternative, defendants ask this court to dismiss so much of the first amended complaint as to SCWA’s market share theory.

Motion to Dismiss

When faced with a motion to dismiss a complaint pursuant to CPLR 3211 (a) (7) for failure to state a cause of action, the court is required to afford the pleading a liberal construction, accept each and every fact as asserted in the pleading to be true, accord the plaintiff the benefit of every possible inference, and determine only whether the facts as alleged fit within any cognizable legal theory. (Rietschel v Maimonides Med. Ctr., 83 AD3d 810 [2d Dept 2011]; Hallman v Kantor, 72 AD3d 895 [2d Dept 2010]; Breytman v Olinville Realty, LLC, 54 AD3d 703 [2d Dept 2008].) In assessing a motion under CPLR 3211 (a) (7), a *578court is free to consider affidavits submitted to aid in support of allowing the complaint to stand (Leon v Martinez, 84 NY2d 83 [1994]; Endless Ocean, LLC v Twomey, Latham, Shea, Kelley, Dubin & Quartararo, 113 AD3d 587 [2d Dept 2014]).

Market Share

Whenever the issue of market share liability comes before a New York court involving a different product, it essentially becomes a case of first impression. As defendants have aptly stated, the theory of recovery has been sanctioned in only one instance by the Court of Appeals in Hymowitz v Eli Lilly & Co. (73 NY2d 487 [1989]). In that case, claims based on market share liability were allowed to proceed in a litigation stemming from injuries caused by DES, a drug administered to pregnant women and later found to cause birth defects, in a situation where plaintiffs were unable, after many years had passed since the marketing of the drug and the appearance of the injuries, to identify the precise company that had manufactured the product giving rise thereto. (Hymowitz at 502.) In identifying the bases for its holding, the Hymowitz court set forth that victims of DES needed a “realistic avenue of relief for plaintiffs injured by DES . . . who [could not] identify the actual manufacturer.” (Id. at 507, 520.) However, the Court made clear that this approach would be limited to those instances where manufacturers of a defective product produced an “identical, generically marketed product, which causes injury many years later” (id. at 508). In addition, the liability of the DES manufacturers was held to be “several” only, to be determined according to each producer’s share of the national market. (Id. at 512-513.)

Following Hymowitz, the United States District Court for the Eastern District of New York found that plaintiffs exposed to Agent Orange were unable to identify the specific manufacturers of the herbicide, a defective generic product which caused harm at a later date, making it impossible to identify the individual tortfeasor. (In re Agent Orange Prod. Liab. Litig., 597 F Supp 740 [ED NY 1984], affd 818 F2d 145 [2d Cir 1987].) In the Agent Orange litigation, as in Hymowitz, the state legislature had revived actions based upon exposure to the product after such had been previously barred by the statute of limitations. (See CPLR 214-c.) Judge Scheindlin permitted the market share liability approach to survive a motion to dismiss in a case involving alleged contamination of groundwater with gasoline additive methyl tertiary butyl ether (MTBE), although the doctrine was *579ultimately not applied in that case. (In re Methyl Tertiary Butyl Ether [‘MTBE”] Prods. Liab. Litig., 447 F Supp 2d 289 [SD NY 2006].) In denying the motion to dismiss the plaintiffs’ claim the court noted that “[u]nder market share liability, the burden of identification shifts to defendants if plaintiff establishes a prima facie case on every element of the claim except for identification of the actual tortfeasor or tortfeasors, and plaintiff has joined manufacturers representing a ‘substantial share’ of the relevant market.” (Id. at 299.)

Since Hymowitz, the courts have been reluctant to apply market share liability in a series of other cases involving product liability and other tort claims. Thus, where the Court of Appeals rejected application of the approach in Hamilton v Beretta US.A. Corp. (96 NY2d 222 [2001]), it stressed that handguns were not identical, fungible items; that the plaintiffs could often identify the manufacturer that caused a particular injury; and because the case was based upon negligent marketing, the plaintiff had not even alleged that such were uniform amongst the defendants therein. (Hamilton at 240-241.)

In Brenner v American Cyanamid Co. (263 AD2d 165 [4th Dept 1999]), the Fourth Department looked at all the reasons why market share liability was applied in Hymowitz, and, finding none of them in a case involving injury arising from ingestion of lead-based paint pigment, rejected its use. First, the Court noted that, in Hymowitz, the plaintiffs defined a national market of DES manufacturers, not easily defined in lead poisoning cases, and that the Hymowitz plaintiffs narrowed to manufacturers who sold DES solely for pregnancy. The Fourth Department found, however, that “[p]laintiffs allege that interior residential white lead paint was unreasonably dangerous, but they have not narrowed the national market to include only those manufacturers of white lead carbonate that sold the product for interior residential use.” (Id. at 171.) Second, while the Hymowitz plaintiffs were able to define the time period in which to apply the market share liability by identifying when the plaintiffs’ mothers ingested DES, the same was not true of the Brenner plaintiffs. (Id. at 172.) Third, lead-based paint, unlike DES, was not an “identical, generically marketed product.” (Id.) Fourth, the Brenner court found that the DES manufacturers exercised exclusive control over their product from the point of manufacture to the point of ingestion; whereas:

“the manufacturers of white lead carbonate did not have exclusive control of the risk. The paint manu*580facturers, rather than the lead pigment manufacturers, decided which pigment to use and in what quantities. In addition, owners and landlords of residences had control over some of the risk posed by lead-based paint, which becomes hazardous when it peels and flakes and is then ingested or the dust inhaled.” (Id.)

Fifth, the Fourth Department noted that the “signature” nature of DES related injuries was not present in the context of injuries arising from exposure to lead-based paint. (Id. at 173.)

In S.F. v Archer-Daniels-Midland Co. (2014 WL 1600414, 2014 US Dist LEXIS 55195 [WD NY, Apr. 21, 2014, No. 13-CV-634S]), the United States District Court for the Western District of New York found that New York’s market share theory would not apply to a product liability claim against manufacturers of high fructose corn syrup because the court found no “ ‘signature injury’ definitively linking the product to the harm”; there was no claim that the injuries were far removed from ingestion of the product; the defendant manufacturers did not “have exclusive control of the risk”; and there existed no legislation suggesting an overriding public interest in allowing those particular claims to proceed. (2014 WL 1600414, *6, 2014 US Dist LEXIS 55195, *17.)

In examining the manufacturer defendants’ motion to dismiss the SCWA’s amended complaint, the court has examined all of the above cases to attempt to resolve the issue of whether or not adoption of a market share theory through use of a national market can be sustained in the case of harm caused by the manufacturers of perchloroethylene. The key case, in the court’s view, is Hymowitz v Eli Lilly & Co. After all is said and done, Chief Judge Wachtler stressed that judicial action was necessitated in the DES arena in order to overcome the “inordinately difficult problems of proof” caused by generically marketed products which were defective from their inception, where the harm caused by the same did not occur until substantial time had passed since ingestion. (Hymowitz at 507.) Under such circumstances, the Court found that equity required that where the injury remained dormant for such a long period and where manufacturers contributed to the devastation, the “ever-evolving dictates of justice and fairness, which are the heart of our common-law system, require [d] formation of a remedy for injuries caused by [the defective product].” (Id.)

In the case of perc, taking as true the allegations set forth by plaintiff in its amended complaint along with the accompanying *581experts’ affidavits, the SCWA has set forth that perchloroethylene is defective from the moment of its manufacture; that it is a generic and fungible product; and that it takes many years from the point of its “ingestion” through seepage into the ground until it appears in one of the water purveyor’s wells, causing extensive environmental harm, in the form of serious property damage. The allegations continue with excerpts from defendants’ witnesses to the effect that the fungible product of one manufacturer of perc becomes commingled with that of another over time and that it is essentially impossible to locate which manufacturer contributed to what extent to the contamination of which particular Water Authority well. In addition, the plaintiff herein has asserted that without application of the market share theory for determining liability, it, like the DES plaintiffs, will be left without remedy for the harm assertedly caused by the chemical manufacturers herein. Plaintiff has further alleged that the product was not only dangerous from the point of manufacture, but, also, that it was reasonably foreseeable that it would cause harm to the groundwater system wherever it was ultimately used. It has assertedly named the entire chemical manufacturing market for the relevant time period and states that its experts are able to track the time periods from product use to resultant property damage.

Based upon the above, especially in the context of a motion brought pursuant to CPLR 3211 (a) (7),1 the court believes that plaintiff has set forth a proper claim for relief and that such is not dismissible as a matter of law. The court, in so holding, does not ignore the cautionary language set forth in Hymowitz, but, rather, looks to the fact that what appear to be the major reasons for its holding are present in this matter. In contrast, those very same elements are found not to be present in Hamilton v Beretta U.S.A. Corp. nor in Brenner v American Cyanamid Co. As stated by plaintiff herein, the Court of Appeals in Hamilton found the very bases for market share set forth in Hymowitz to be absent, i.e., handguns are not identical fungible products and the manufacturers of the same are possible to identify. (.Hamilton at 240-241.) In addition, the assertion in the current complaint is that the product was defective the very moment it left the manufacturers’ control and did not become dangerous, *582as in the case of handguns, only through the use of third parties.2 Similarly, in Brenner, there was again a finding that lead paint is not a fungible product remaining unchanged from manufacture to ingestion, it was not a generically marketed product, the identical nature of the injuries alleged were absent, and the plaintiffs had not narrowed a national market to include only manufacturers that sold the product for interior use — the area from which the harm assertedly rose. (.Brenner at 171-173.) In S.F. v Archer-Daniels-Midland Co., the court found again no signature injuiy nor a long period from the time of ingestion to the time of injuiy (2014 WL 1600414, *6, 2014 US Dist LEXIS 55195, *17).

This court, of course, recognizes that Brenner distinguishes the lead-based paint from DES for the additional reason that other parties contributed to the harm, an issue which does exist in the case at bar. However, it is this court’s opinion that this case is distinguishable from Brenner because lead-based paint was found not to involve a generically marketed fungible product, the plaintiffs therein failed to identify the necessary market of manufacturers of interior lead paint, and the complaint did not contain a claim, as herein, that the manufacture itself was dangerous resulting in serious harm. For the foregoing reasons, this court finds both Brenner and Hamilton distinguishable from this case.

The court notes that although it is denying a motion to dismiss a pleading, this does not absolve the plaintiff from the requirements of ultimately sustaining its burden of proving the dangerous nature of the product at the time of its manufacture and sale, the forseeability of harm caused from the point of manufacture, and the damage proximately caused therefrom. In addition, as discussed in conference with counsel for the parties involved, this court will grant the request made on behalf of the chemical manufacturers that if it allows the complaint to proceed as amended, they will be entitled to additional discovery relevant to the new allegations made therein.

However, the court does not agree that if it is found that the product as designed was dangerous and that such danger arose from the point of manufacture, in conjunction with fungibility *583and the impossibility of designating chemical defendants, all of whom are set forth in this action, as well as a lengthy latency period, that plaintiff cannot utilize the market share theory in this case. Accordingly, defendants’ motion to dismiss the SCWA’s amended complaint is denied.

DALIANIS, C.J.

The defendants, Exxon Mobil Corporation and Exxon-Mobil Oil Corporation (collectively, either Exxon or ExxonMobil), appeal-from a jury verdict awarding approximately $236 million in damages due to groundwater contamination to the plaintiff, the State of New Hampshire, after a trial in Superior Court {Fauver, J.). The State cross-appeals from the trial court’s order imposing a trust upon approximately $195 million of the damages award. We affirm the trial court’s rulings on the merits and reverse its imposition of a trust.

I. Background

In 1990, Congress amended the Federal Clean Air Act to require the use of an “oxygenate” in gasoline in areas not meeting certain national air quality standards. See 42 U.S.C. § 7545(k) (Supp. 1991) (amended 2005, 2007). An oxygenate is a substance used to reduce gasoline emissions. See Oxygenated Fuels Ass’n Inc. v. Davis, 331 F.3d 665, 666 (9th Cir.2003). The amendment did not mandate the use of any particular oxygenate; it simply required that “[t]he oxygen content of the gasoline shall equal or exceed 2.0 percent by weight.” 42 U.S.C. § 7545(k)(2)(B). To implement the requirement, the Environmental Protection Agency (EPA) launched the Reformulated Gasoline Program (RFG Program), which required gasoline contain*219ing an oxygenate of the manufacturer’s choice. See 40 C.F.R. § 80.46(g)(9)(i) (2000). Methyl tertiary butyl ether (MTBE) was one among several possible oxygenates. Id. MTBE is a gasoline additive that increases the octane levels of fuels. Metropolitan areas with significant concentrations of ambient ozone were required to use reformulated gasoline. See 42 U.S.C. § 7545(k). Other areas, like New Hampshire, could opt in to the program to receive credit toward mandatory emissions reduction requirements. See 42 U.S.C. § 7545(k)(6)(A).

New Hampshire joined the RFG Program in 1991, with respect to the State’s four southern-most counties, effective January 1, 1995. Between 1995 and 2006, gasoline with MTBE was sold throughout the State. In 1997, employees at the New Hampshire Department of Environmental Services (DES) became aware that MTBE could pose increased risks to groundwater. In 1998, studies from Maine and California raised concerns about MTBE. In 1999, DES adopted regulations setting a maximum contaminant level for MTBE in drinking water and groundwater at 13 parts per billion (ppb).

In 2000, the EPA advised:

MTBE is capable of traveling through soil rapidly, is very soluble in water ... and is highly resistant to biodegradation .... MTBE that enters groundwater moves at nearly the same velocity as the groundwater itself. As a result, it often travels farther than other gasoline constituents, making it more likely to impact public and private drinking water wells. Due to its affinity for water and its tendency to form large contamination plumes in groundwater, and because MTBE is highly resistant to biodegradation and remediation, gasoline releases with MTBE can be substantially more difficult and costly to remediate than gasoline releases that do not contain MTBE.

Advance Notice of Intent to Initiate Rulemaking under the Toxic Substance Control Act to Eliminate or Limit the Use of MTBE as a Fuel Additive in Gasoline, 65 Fed. Reg. 16094, 16097 (Mar. 24, 2000).

In 2001, the Governor petitioned the EPA to allow the State to opt out of the RFG Program, but did not receive a reply until 2004. See Removal of the Reformulated Gasoline Program From Four Counties in New Hampshire, 69 Fed. Reg. 4903 (Feb. 2, 2004). In 2004, the legislature enacted legislation banning MTBE gasoline effective in 2007. See RSA 146-G:12 (2005) (repealed 2015). In 2005, Congress eliminated the oxygenate requirement and enacted a renewable fuels mandate to increase ethanol usage. See Energy Policy Act of 2005, Pub. L. No. 109-58, §§ 1501, 1504, 119 Stat. 594, 1067, 1076 (2005).

*220In 2008, New Hampshire sued several gasoline suppliers, refiners, and chemical manufacturers seeking damages for groundwater contamination allegedly caused by MTBE. Before trial, all defendants except Exxon settled with the State. After almost ten years of litigation, the case went to trial in 2013 on three causes of action: negligence; strict liability — design defect; and strict liability — failure to warn. After an approximately three-month trial, the jury found in favor of the State on all of its claims. The jury rejected Exxon’s defenses that “in designing its MTBE gasoline, it complied with the state of the art”; that “the hazards posed by the use of MTBE in gasoline were obvious, or were known and recognized by the State”; and that Exxon “provided distributors with adequate warnings of the hazards of MTBE gasoline.” The jury also found that Exxon failed to prove that “the actions of someone other than the State or ExxonMobil (which were not reasonably foreseeable to ExxonMobil) were the sole cause of the State’s harm,” that “the State committed misconduct that contributed to its harm,” or that some or all of Exxon’s fault should be allocated to certain nonparties.

The jury awarded total damages in the amount of $816,768,018. These damages included: (a) $142,120,005 for past cleanup costs; (b) $218,219,948 to assess and clean up 228 high-risk sites; (c) $305,821,080 for sampling drinking water wells; and (d) $150,607,035 for treating drinking water wells contaminated with MTBE at or above the maximum contaminant level. The jury found that Exxon’s market share for gasoline in New Hampshire during the applicable time period was 28.94%. Accordingly, the trial court entered an amended verdict of $236,372,644 against Exxon. The trial court subsequently awarded the State prejudgnient interest in accordance with RSA 524:l-b (2007).

On appeal, Exxon contends that: (1) the State’s suit should have been dismissed on the grounds of separation of powers and due process; (2) the suit should have been dismissed due to waiver; (3) the State’s claims are preempted by the 1990 amendments to the Federal Clean Air Act; (4) the State failed to establish that Exxon departed from the applicable standard of care; (5) Exxon did not have a duty to warn the State; (6) market share liability is not an acceptable theory of recovery; (7) the State should not have been permitted to rely upon aggregate statistical evidence; (8) Exxon was unfairly prejudiced in its ability to present evidence of fault on the part of other nonparties; (9) the trial court erred in deciding the State had parens patriae standing; (10) the State’s damages claims for future well impacts are not ripe; and (11) the trial court erred in awarding prejudgment interest on future costs.

*221 II. Separation of Powers and Due Process

Exxon argues that the State’s suit should have been dismissed on the grounds of separation of powers and due process. Exxon asserts that based upon the State’s decision to participate in the RFG Program beginning in 1991, and the legislature’s failure to ban MTBE before 2007, “[t]he retroactive no-MTBE duty” imposed upon it “conflicts with bedrock principles of the separation of powers” and “due process.” Exxon also argues that the suit conflicts with the Oil Discharge and Disposal Cleanup Fund (ODD Fund), RSA ch. 146-D (Supp. 2014); see Laws 2014, 177:1 (repealing RSA chapter 146-D, eff. July 1 2025), and the Gasoline Remediation and Elimination of Ethers Fund (GREE Fund), RSA ch. 146-G (Supp. 2014); see Laws 2014, 177:3,1 (repealing RSA chapter 146-G, excluding RSA 146-G:9, eff. July 1, 2025), Laws 2014, 177:3, II (repealing RSA 146-G:9, eff. October 1, 2025). The State, asserts that Exxon failed to preserve its separation of powers argument because the arguments it raises on appeal were not made to the trial court, and that Exxon fails to identify where it preserved its due process argument.

The appealing party bears the burden of demonstrating that it “specifically raised the arguments articulated in [its appellate] brief before the trial court.” Dukette v. Brazas, 166 N.H. 252, 255 (2014). Generally, the failure to do so bars a party from raising such claims on appeal. N. Country Envtl. Servs. v. Town of Bethlehem, 150 N.H. 606, 619 (2004). But see Sup. Ct. R. 16-A (plain error rule). We have reviewed the record and agree with the State that Exxon failed to preserve its separation of powers argument concerning the State’s purported public policy decisions, as well as its due process argument. However, we address, as properly preserved, Exxon’s separation of powers argument based upon the ODD and GREE Funds.

Before trial, Exxon moved for summary judgment on separation of powers grounds, arguing that the State’s suit threatened to usurp the legislature’s appropriations power because the ODD and GREE Funds “embody the legislative choice regarding how testing and remediation should be funded” and “this suit would allow the Attorney General to fund remediation in a very different way and create an appropriation outside of the General Court’s purview.” Exxon asserted that, because “there is no existing statutory mechanism through which any damages awarded to the State in this litigation could be specifically appropriated to the investigation, testing, and remediation the State requests,” it would violate separation of powers for the court or the attorney general “to order such an appropriation.” Thus, Exxon argued, “[i]n light of the existing funds and their structure, this suit implicates appropriations-related separation of powers problems.”

*222The trial court denied the motion, concluding that Exxon had failed to establish that the legislature intended the ODD or GREE Funds to be the State’s exclusive remedy. As to the ODD Fund, the court found that pursuant to the plain language of RSA 146-D:6,1, and I-a, the Fund “is only authorized to disburse funds to owners of underground storage facilities, bulk storage facilities, or the land on which such facilities are stored” and, thus, the statute did not demonstrate legislative intent “to provide a remedy for the damages sought by the State in this litigation.” As to the GREE Fund, although noting that it does not contain an explicit limitation upon who may seek payment, because the potential damages at issue in this suit far exceed the $2,500,000 capped balance of the fund, the trial court stated that

[i]t is reasonable to infer, then, that in creating the GREE Fund the legislature did not intend it to serve as the sole source of cleanup funds for any and all contamination event[s]. Its relatively small size indicates that it was intended to address a small number of isolated incidents at any given time, not a statewide contamination of the type alleged here by the State. Finally, the Court notes that neither fund claims to be an exclusive remedy.

Accordingly, the court found that “the existence of these funds does not evince the intent of the legislature to preclude suits such as this one” and that “the State’s suit does not threaten to usurp the legislature’s appropriations power.”

On appeal, Exxon argues that the legislature “created two detailed statutory schemes — the ODD Fund and the GREE Fund — to enable direct spillers to pay the often substantial costs of remediation,” and that “[i]t is precisely when the legislature has established a tailored regulatory framework to address a particular problem that this Court has declined to make judicial ‘improvements’ to the democratically-enacted scheme.” The State argues that its suit “is consistent with the ODD and GREE funds” in that the “caps on those funds, their purposes, and their structures confirm that neither was intended to replace recovery actions for tortious activity against manufacturers of dangerous products or to free manufacturers that withhold knowledge of a dangerous condition from liability.”

Whether the State’s lawsuit violates the Separation of Powers Clause of the State Constitution, N.H. Const. pt. I, art. 37, because it conflicts with the ODD and GREE Funds, is a question of law, which we review de novo. See Cloutier v. State, 163 N.H. 445, 451 (2012). “The separation of powers among the legislative, executive and judicial branches of government is an important part of its constitutional fabric.” Duquette v. Warden, N.H. State Prison, 154 N.H. 737, 746 (2007). “Separation of the three co-equal *223branches of government is essential to protect against a seizure of control by one branch that would threaten the ability of our citizens to remain a free and sovereign people.” Id. Thus, under the Separation of Powers Clause, “each branch is prohibited . .. from encroaching upon the powers and functions of another branch.” Id. at 746-47. Nevertheless, Part I, Article 37 does “not provide for impenetrable barriers between the branches ... and the doctrine is violated only when one branch usurps an essential power of another.” Id. at 747 (citation omitted).

Statutory interpretation is a question of law, which we review de novo. Appeal of Local Gov’t Ctr., 165 N.H. 790, 804 (2014). In matters of statutory interpretation, we are the final arbiter of the intent of the legislature, as expressed in the words of the statute considered as a whole. Id. We first look to the language of the statute itself, and, if possible, construe that language according to its plain and ordinary meaning. Id. We interpret legislative intent from the statute as written and will not consider what the legislature might have said or add language that the legislature did not see fit to include. Id. Statutory “provisions barring [a] common law right to recover are to be strictly construed.” Estate of Gordon-Couture v. Brown, 152 N.H. 265, 267 (2005). “If such a right is to be taken away, it must be expressed clearly by the legislature.” Id. at 266.

The purpose of the ODD Fund is “to establish financial responsibility for the cleanup of oil discharge and disposal, and to establish a fund to be used in addressing the costs incurred by the owners of underground storage facilities and bulk storage facilities for the cleanup of oil discharge and disposal.” RSA 146-D:1 (emphasis added). The ODD Fund allows owners of eligible facilities to apply for reimbursement of court-ordered damages to third parties for injury or property damage and costs of cleanup of oil discharges up to $1,500,000. RSA 146-D:6, III. The ODD Fund is financed by a fee on imported oil that is paid on a per gallon basis by distributors who import oil into New Hampshire. RSA 146-D:2-:3. As the trial court found, “the end goal of the ODD Fund is not to offset tort liability for Defendants but rather to provide an excess insurance mechanism for [underground storage tank] owners who are otherwise in compliance with all relevant laws and rules.”

The purpose of the GREE Fund, a fund in addition to both the Oil Pollution Control Fund established pursuant to RSA 146-A:ll-a (Supp. 2014) and the ODD Fund, “is to provide procedures that will expedite the cleanup of gasoline ether spillage, mitigate the adverse [e]ffects of gasoline ether discharges, encourage preventive measures, impose a fee upon importers of neat gasoline ethers into the state and establish a fund for the remediation of groundwater and surface water contaminated by gasoline *224ethers.” RSA 146-G:1, II. “Th[e GREE] nonlapsing, revolving fund shall be used .... to mitigate the adverse [e]ffects of gasoline ether discharges including, but not limited to, provision of emergency water supplies to persons affected by such pollution, and . . . the establishment of an acceptable source of potable water to injured parties.” RSA 146-G:4,1. “Not more than $150,000 shall be allocated annually for research programs dedicated to the development and improvement of preventive and cleanup measures concerning such gasoline ether discharges.” Id. The fund’s balance is capped at $2,500,000. RSA 146-G:4, II. The fund is financed in part by the ODD Fund. RSA 146-D:3, VI(b); RSA 146-G:1.

We agree with the trial court that there is no language in either of the statutory provisions establishing the ODD and GREE Funds indicating a legislative intent to preclude the damages sought by the State in this case. See also State v. Hess Corp., 161 N.H. 426, 431 (2011) (MTBE defendants conceded that the State may recover damages to test and treat statutorily defined public water systems). Accordingly, we reject Exxon’s separation of powers argument based upon the ODD and GREE Funds.

III. Waiver

Exxon argues that the State’s suit should have been dismissed due to waiver. Before trial, Exxon moved for summary judgment, arguing, in part, that “by requiring that RFG ... gasoline be sold in New Hampshire, with full knowledge that such gasoline would contain MTBE and with full knowledge of all of MTBE’s alleged defective properties, the State cannot now be allowed to sue Defendants who thereafter complied with the State’s demands and supplied MTBE gasoline to the State.” (Quotation omitted.) In denying the motion, the trial court noted that, because Exxon did not assert that the State expressly waived its right to sue for harm from MTBE, Exxon could only proceed under an implied waiver theory. The court found that there were “genuine issues of disputed fact regarding the State’s knowledge, [Exxon’s] knowledge, and timing of this awareness.”

Following the jury verdict, Exxon moved to set aside the verdict and for a new trial. Exxon argued, in part, that it was “unfairly prejudiced” when the trial court instructed the jury on waiver in its preliminary instructions “but then refused to include that instruction in its final instructions or in the verdict form.” In its order denying Exxon’s motion, the trial court explained:

In its motion for summary judgment on waiver, Exxon argued that the State knew MTBE’s characteristics but still opted in to the RFG program, thereby waiving any claims it had or would *225develop regarding MTBE contamination. However, the State disputed its level of knowledge. During trial, Exxon attempted to prove the State’s knowledge by presenting witnesses that testified that MTBE’s characteristics were widely known and understood thereby suggesting the State should have known about MTBE.

The State countered this testimony with its own witnesses explaining that the first time State employees found MTBE in a contamination site, those employees were unable to identify the compound and asked the U.S. EPA for assistance. The State also presented testimony that it did not become aware of MTBE’s full nature until the State of Maine published a study.

This testimony goes to the issue of waiver but it is also relevant to the issue of [the State’s] misconduct, and the Court gave an instruction on [the State’s] misconduct. In fact, the Court instruction on [the State’s] misconduct encompassed the same elements embodied in a waiver claim.

(Citations omitted.)

On appeal, Exxon argues that, “with knowledge of MTBE groundwater risks, the State opted-in to the RFG program, participated in that program for years, repeatedly opposed banning MTBE, and ultimately decided in 2004 that continuing MTBE’s use for nearly three more years was better for the State than an outright ban.” Thus, there was “ample evidence to support a jury verdict finding waiver,” and the trial court’s “failure to instruct the jury is clear error.” Exxon also argues that the trial court’s reasoning that a waiver instruction was unnecessary is erroneous, “as misconduct and waiver are distinct defenses that are appropriately charged separately.” The State argues that, at trial, Exxon adduced no evidence of express or implied waiver, that the special verdict form reflects that the jury rejected Exxon’s defense “that the hazards posed by the use of MTBE in gasoline were obvious, or were known and recognized by the State,” and that, in any event, the trial court “correctly concluded that its misconduct instruction adequately encompassed Exxon’s waiver defense.”

Whether a particular jury instruction is necessary and the exact scope and wording of jury instructions are within the sound discretion of the trial court. See State v. Littlefield, 152 N.H. 331, 334 (2005). We review the trial court’s decisions on these matters for an unsustainable exercise of discretion. Id.

Exxon’s “plaintiffs misconduct defense” jury instruction as given by the trial court provided in pertinent part:

*226If you find that ExxonMobil’s product was unreasonably dangerous, ExxonMobil failed to provide a warning, or behaved negligently and that ExxonMobil is liable, you should then go on to determine if the State committed misconduct that contributed to cause its injuries. With respect to the State’s alleged misconduct, ExxonMobil bears the burden to prove that it is more likely than not that the State committed misconduct in its use of the product.

Misconduct includes, but is not limited to, abnormal use of the product, misuse of the product, failing to discover or foresee dangers that the ordinary person or entity would have discovered or foreseen, voluntarily proceeding to encounter a knoum danger, and failing to mitigate damages.

(Emphasis added.)

We note that in its motion for judgment notwithstanding the verdict (JNOV) following the jury verdict, Exxon made the same argument regarding its misconduct defense that it makes on appeal regarding waiver. Asserting in its motion for JNOV that the evidence “overwhelmingly proved ExxonMobil’s affirmative defenses,” Exxon argued that “[t]he evidence at trial overwhelmingly proves that the State’s misconduct contributed to its injuries. First, the evidence established that the State voluntarily encountered a known danger by opting-in to the RFG program with knowledge of MTBE’s characteristics. Moreover, the evidence demonstrates that the State knew that MTBE would be used in New Hampshire to comply with the RFG program.” (Citation omitted.) In support of its waiver argument on appeal, Exxon asserts that “with knowledge of MTBE groundwater risks, the State opted-in to the RFG program [and] participated in that program for years.”

Concluding that the waiver and misconduct instructions are similar because they both address the State’s knowledge and subsequent actions based upon that knowledge, the trial court reasoned:

Depending on the State’s knowledge, the jury could have found that the State knew or shotdd have known the characteristics of MTBE gasoline and thereby either waived any challenge it is now raising or should have been held partially responsible for its own injury. In other words, because the jury was instructed on and considered the issue of the State’s knowledge — that the State knew of MTBE and used it anyway — the jury also considered whether the State waived any claims about MTBE contamination risks by knowingly using MTBE. The jury nonetheless rejected this theory. Thus, Exxon was not entitled to an independent *227waiver instruction because the plaintiff’s misconduct instruction encompassed this affirmative defense.

Assuming, without deciding, that there was enough evidence for Exxon’s implied waiver defense to go to the jury, we hold that any error was harmless given the jury’s finding that the State did not commit misconduct that contributed to its harm.

IV. Federal Preemption

Exxon argues that the State’s claims are preempted by the Federal Clean Air Act. Before trial, Exxon moved for summary judgment, arguing that Congress and the EPA “took actions providing that federal requirements were to be met by allowing refiners to choose MTBE as an additive to gasoline,” and that “State law is preempted where it seeks to ban an action that federal law affirmatively chooses to make available to state actors.” The trial court rejected Exxon’s argument that the State’s tort claims present an obstacle to the federal purpose of the Clean Air Act.

Noting that “[o]n numerous occasions, courts throughout the United States have considered whether the [Clean Air Act] preempts state tort law claims regarding the use of MTBE,” the trial court applied the reasoning of the United States District Court for the Southern District of New York. The trial court explained that Exxon’s arguments

are essentially identical to those made by the defendants during In re MTBE Products Liability Litigation. Here, the Defendants claim that the federal regulation deliberately provided manufacturers with a range of oxygenate choices and the choice was designed to further the regulation’s objectives. The Defendants further argue that Congress and the EPA stressed the importance of MTBE as a choice and encouraged its use. Finally, they point to the lengthy legislative history of the [Clean Air Act] to support their arguments.

See In re Methyl Tertiary Butyl Ether (MTBE) Products, 457 F. Supp. 2d 324, 336-42 (S.D.N.Y. 2006), aff'd, 725 F.3d 65 (2d Cir. 2013), cert. denied, 134 S. Ct. 1877 (2014). The trial court concluded that “[l]ike the defendants [in MTBE Products], the Defendants here have failed to prove that the State’s tort law claims are preempted by the [Clean Air Act], and their use of the legislative history is irrelevant due to the unambiguous language of the [Act].

Exxon moved for a directed verdict at the close of the State’s case-in-chief, based in part upon its assertion that the evidence presented *228“demonstrates that the State’s claims are preempted based on the Clean Air Act’s requirement that gasoline contain an oxygenate and the factual evidence demonstrating that no feasible alternative oxygenate existed sufficient to meet the requirements of RFG in New Hampshire.” Noting that Exxon’s argument “is presented in a highly summary fashion,” the trial court declined to revisit the preemption claim and relied upon its earlier decision denying Exxon’s motion for summary judgment.

After the jury verdict, Exxon moved to set aside the verdict and for a new trial arguing, in part, that the trial court “failed to instruct the jury on ExxonMobil’s affirmative defense of preemption or include it in the verdict form.” According to Exxon, the trial court erred because “there were sufficient facts” to support its argument “that MTBE was the only feasible oxygenate for use in New Hampshire” and, therefore, “the State’s claim would be preempted because ExxonMobil was required to use an oxygenate under the Clean Air Act Amendments.” Exxon asserted also that “as a matter of law, the State’s claims were preempted . . . because Congress specifically intended for refiners to be able to choose among oxygenates, including MTBE, to comply with the RFG program and eliminating MTBE would have interfered with the goals of the [Act].”

Noting that “[t]he preemption argument Exxon raises directly alleges the argument it raised pretrial and in its directed verdict motion,” the trial court denied the motion. The court reasoned that

[t]o the extent Exxon argues the jury should have been instructed on preemption in order to find facts from which the Court could further evaluate preemption, the Court considered and rejected this argument in its [order denying Exxon’s motion for a directed verdict]. Even assuming New Hampshire courts would adopt this view of preemption, there are no facts to support Exxon’s theory. Exxon alleges the State’s claims are preempted by the federal Clean Air Act and its RFG program. The Court rejected this legal argument. There are no facts that a jury could find that would alter the legal analysis this Court already undertook.

(Citation omitted.)

On appeal, Exxon argues that a state tort duty holding it liable for supplying MTBE is preempted by the Clean Air Act, “particularly because Exxon had no safer, feasible alternative to MTBE at the time.” According to Exxon, “[preemption here follows a fortiori from” Geier v. American Honda Motor Co., 529 U.S. 861 (2000), and Williamson v. Mazda Motor of America, Inc., 562 U.S. 328 (2011), “which establish that when federal law imposes a mandate but leaves private parties with a choice of how to comply, a state-law tort duty that would take one option off the table *229obstructs federal objectives when maintaining the choice is a ‘significant objective’ of the federal program.” Exxon asserts that despite “ample evidence that there was no safer, feasible alternative to MTBE,” the trial court erroneously refused to instruct the jury on this issue. The State argues that “[preemption arguments like the one Exxon raises here have been rejected by every federal court of appeals to consider them.” The State contends that “enabling suppliers to choose MTBE (as opposed to ethanol) was not a significant regulatory objective of Congress or EPA,” and that the trial evidence demonstrated that “safer, feasible alternatives to MTBE existed.” (Quotations omitted.)

Because the trial court’s determination of federal preemption is a matter of law, our review is de novo. N.H. Attorney Gen. v. Bass Victory Comm., 166 N.H. 796, 801 (2014). The federal preemption doctrine is based upon the Supremacy Clause of the United States Constitution. See Arizona v. United States, 132 S. Ct. 2492, 2500 (2012); see also Appeal of Sinclair Machine Prod’s, Inc., 126 N.H. 822, 826 (1985). Article VI provides that federal law “shall be the supreme law of the land; and the judges in every state shall be bound thereby, anything in the Constitution or laws of any state to the contrary notwithstanding.” U.S. CONST, art. VI. “Accordingly, it has long been settled that state laws that conflict with federal law are without effect.” Mutual Pharmaceutical Co., Inc. v. Bartlett, 133 S. Ct. 2466, 2473 (2013) (quotation omitted).

Congress may preempt state law under the Supremacy Clause in several ways. Hillsborough County v. Automated Medical Labs., 471 U.S. 707, 713 (1985). First, within constitutional limits, “Congress is empowered to pre-empt state law by so stating in express terms.” Id. “In the absence of express pre-emptive language, Congress’ intent to pre-empt all state law in a particular area may be inferred where the scheme of federal regulation is sufficiently comprehensive to make reasonable the inference that Congress left no room for supplementary state regulation.” Id. (quotation omitted).

“Even where Congress has not completely displaced state regulation in a specific area, state law is nullified to the extent that it actually conflicts with federal law.” Id. This “conflict preemption” arises when “compliance with both federal and state regulations is a physical impossibility, or when state law stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress.” Id. (quotations and citation omitted).

Exxon relies upon the so-called “obstacle branch” of conflict preemption — that state law “stand[s] as an obstacle to the accomplish*230ment and execution of the full purposes and objectives of Congress.” Arizona, 132 S. Ct. at 2501 (quotation omitted). “The burden of establishing obstacle preemption ... is heavy: the mere fact of tension between federal and state law is generally not enough to establish an obstacle supporting preemption, particularly when the state law' involves the exercise of traditional police power.” MTBE Products Liability Litigation, 725 F.3d 65, 101-02 (2d Cir. 2013) (quotations and brackets omitted), cert. denied, 134 S. Ct. 1877 (2014). “Indeed, federal law does not preempt state law under obstacle preemption analysis unless the repugnance or conflict is so direct and positive that the two acts cannot be reconciled or consistently stand together.” Id. at 102 (quotation omitted).

“The control and elimination of water pollution is a subject clearly within the scope of the police power” of the State. Shirley v. Commission, 100 N.H. 294, 299 (1956). “Consideration of issues arising under the Supremacy Clause starts with the assumption that the historic police powers of the States are not to be superseded by Federal Act unless that is the clear and manifest purpose of Congress.” Cipollone v. Liggett Group, Inc., 505 U.S. 504, 516 (1992) (quotation, brackets, and ellipses omitted). “Accordingly, the purpose of Congress is the ultimate touchstone of pre-emption analysis.” Id. (quotations and brackets omitted). “Since preemption of any type fundamentally is a question of congressional intent, our preemption analysis begins with the source of the alleged preemption.” Bass Victory Comm., 166 N.H. at 803 (quotation, brackets, and citation omitted).

As discussed above, in 1990, Congress enacted amendments to the Clean Air Act that, among other things, created the RFG Program. See 42 U.S.C. § 7545(k). The RFG Program required gasoline used in specific geographic areas to have a minimum oxygen content, achieved by the addition of an oxygenate of the manufacturer’s choice. See 42 U.S.C. §§ 7545(k)(2)(B), (m)(2); see also 40 C.F.R. § 80.46(g)(9)(i). After the passage of the amendments, the EPA certified various blends of gasoline for use in the RFG Program, including gasoline containing MTBE, but did not mandate the use of any one oxygenate. As the United States Court of Appeals for the Second Circuit explained,

the 1990 Amendments did not require, either expressly or implicitly, that Exxon use MTBE. Although the 1990 Amendments required that gasoline in certain geographic areas contain a minimum level of oxygen, they did not prescribe a means by which manufacturers were to comply with this requirement. The EPA identified MTBE as one additive that could be used to “certify” gasoline, but certification of a fuel meant only that it satisfied *231certain conditions in reducing air pollution. Neither the statute nor the regulations required Exxon to use MTBE, rather than other oxygenates, such as ethanol, in its gasoline.

MTBE Products Liability Litigation, 725 F.3d at 98 (citations omitted).

We disagree with Exxon that preemption here “follows a fortiori” from Geier and Williamson. Those cases both considered portions of Federal Motor Vehicle Safety Standard 208 (FMVSS 208), promulgated pursuant to the National Traffic and Motor Vehicle Safety Act of 1966. In Geier, a 1984 version of FMVSS 208 required manufacturers to equip their vehicles with passive restraint systems, but gave manufacturers a choice among several different passive restraint systems, including airbags and automatic seatbelts. Geier, 529 U.S. at 864-65, 875. The question before the United States Supreme Court was whether the Act, together with the regulation, preempted a state tort suit that would have held a manufacturer liable for not installing airbags. See id. at 865. In determining whether, in fact, the state tort action conflicted with federal law, the Court considered whether the state law stood as an “obstacle” to the objectives of the federal law. Id. at 886. After examining the regulation, including its history, the promulgating agency’s contemporaneous explanation of its objectives, and the agency’s current views of the regulation’s preemptive effect, the Court concluded that giving auto manufacturers a choice among different kinds of passive restraint devices was a significant objective of the federal regulation. Id. at 874-83. Because the tort suit stood as an obstacle to the accomplishment of that objective in that the suit would have deprived the manufacturers of the choice among passive restraint systems that the federal regulation gave them, the Court found the state tort suit preempted. Id. at 886.

In Williamson, the Supreme Court considered a 1989 version of FMVSS 208 requiring that auto manufacturers install seatbelts on the rear seats of passenger vehicles. Williamson, 562 U.S. at 326. The law required manufacturers to install lap-and-shoulder belts on seats next to a vehicle’s doors or frames but gave them a choice of installing either simple lap belts or lap-and-shoulder belts on rear inner seats. Id. The Court noted that like the regulation in Geier, the regulation at issue before it left the manufacturer with a choice and, like the tort suit in Geier, the tort suit at issue would restrict that choice. Id. at 332. However, after reviewing the history of the regulation before it, including the agency’s explanation of the reasons for not requiring lap-and-shoulder belts for rear inner seats and the Solicitor General’s representations of the agency’s views, the Court concluded that providing manufacturers with this seatbelt choice was not a significant objective of the federal regulation. Id. at 334-36. Thus, the Court concluded *232that because the choice of the type of restraint was not a significant regulatory objective, the state tort suit was not preempted. Id.

Exxon does not point to any part of the Clean Air Act or its legislative history that supports a conclusion that the choice among oxygenate options was a significant objective of the federal law. Indeed, “[t]he [Clean Air Act] itself contains no language mandating that [Exxon] have a choice among oxygenates.” In re Methyl Tertiary Butyl Ether (MTBE) Products, 457 F. Supp. 2d at 336-37. Unlike Geier, in which the federal regulation deliberately provided the manufacturer with a range of choices among different passive restraint devices, “[h]ere, the choice of oxygenate options is a means towards improving air quality, and the existence of the choice itself is not critical to furthering that goal.” MTBE Products Liability Litigation, 725 F.3d at 98 n.15. “Geier does not stand... for the proposition that any time an agency gives manufacturers a choice between two or more options, a tort suit that imposes liability on the basis of one of the options is an obstacle to the achievement of a federal regulatory objective and may be pre-empted.” Williamson, 562 U.S. at 337 (Sotomayor, J.,' concurring). Rather, “a conflict results only when [the regulation] . . . does not just set out options for compliance, but also provides that the regulated parties must remain free to choose among those options.” Id. at 338 (quotation omitted).

We reject Exxon’s argument that “[d]espite ample evidence that there was no safer, feasible alternative to MTBE,” the trial court’s refusal to instruct the jury on this issue was error because “preemption questions can be informed by questions of fact.” Exxon asserts that “[a]t the summary judgment stage, the [trial court] rejected the purely legal argument that the State’s claims would be preempted even if there were safer, feasible alternatives, but later . . . refused to consider the different and fact-dependent question whether preemption would apply if Exxon had no safer, feasible alternative.” (Citation omitted.)

The record shows, however, that Exxon’s proposed jury instruction did not ask the jury to find whether there was no safer feasible alternative to MTBE. Rather, the proposed instruction asked “whether prohibiting the use of MTBE in gasoline during the period at issue here would have resulted in delays and increased costs to the expansion of the federal RFG program,” thus establishing preemption. (Emphasis added.) This position has been rejected as a matter of law. See MTBE Products Liability Litigation, 725 F.3d at 103 (although legislative materials demonstrate that Congress was sensitive to the magnitude of the economic burdens it might be imposing by virtue of the RFG Program, “they hardly establish that Congress had a ‘clear and manifest intent’ to preempt state tort judgments *233that might be premised on the use of one approved oxygenate over a slightly more expensive one”); Oxygenated Fuels Ass’n Inc., 331 F.3d at 673 (plaintiff “offered virtually no support for its assertion that the Clean Air Act’s goals — for purposes of preemption analysis — are a smoothly functioning market and cheap gasoline”).

We agree with several other courts that have addressed and rejected the issue of preemption and MTBE. See, e.g., MTBE Products Liability Litigation, 725 F.3d at 100-03 (rejecting Exxon’s obstacle branch preemption arguments); In re Methyl Tertiary Butyl Ether (MTBE) Products, 739 F. Supp. 2d at 601-02 (allowing plaintiffs to recover damages for inordinate environmental effects'caused by the use of MTBE does not conflict with federal policy, and rejecting Exxon’s arguments that because there was no safer, feasible alternative to MTBE, it was impossible for Exxon to comply with federal requirements without using MTBE); In re Methyl Tertiary Butyl Ether (MTBE) Products, 457 F. Supp. 2d at 343 (“Just as the many other courts that have addressed the issue of preemption and MTBE, this Court finds that plaintiffs’ tort law claims are not preempted.”); Oxygenated Fuels Ass’n, Inc. v. Pataki, 293 F. Supp. 2d 170, 172, 182-83 (N.D.N.Y. 2003) (concluding after bench trial that New York MTBE ban does not conflict with any aspect of Clean Air Act); Exxon Mobil Corp. v. U.S. E.P.A., 217 F.3d 1246, 1256 (9th Cir. 2000) (Nevada regulation, requiring that all gasoline sold in wintertime have an oxygen content of at least 3.5 percent does not conflict with, and is not preempted by,. any provision of the Clean Air Act); Abundiz v. Explorer Pipeline Co., No. CIV. 3:00-CV-H, 00-2029, 2002 WL 1592604, at *3-5 (N.D. Tex. July 17, 2002) (Geier does not compel a finding that state MTBE regulations are preempted).

We hold as a matter of law that the State’s claims are not preempted by federal law, and that the trial court did not err in refusing Exxon’s proposed jury instruction.

V. Standard of Care

Exxon argues that the State failed to establish that it departed from the applicable standard of care “simply by marketing MTBE.” In its motion for a directed verdict at the close of the State’s case-in-chief, Exxon argued that “[i]n order to establish that ExxonMobil breached its duty of care, the State was obligated to present evidence that ExxonMobil failed to act pursuant to what reasonable prudence would require under similar circumstances.” (Quotation omitted.) Exxon asserted that, because the evidence presented at trial “demonstrated that the entire industry acted in the same manner in using gasoline containing MTBE in New Hampshire,” there was *234“no evidence to establish the standard of care or what a reasonable manufacturer or supplier would have done, let alone that ExxonMobil deviated from any applicable standard of care.”

The trial court denied Exxon’s motion, rejecting its argument that because the State did not present evidence regarding the care exercised by other manufacturers and refiners in the industry, the State failed to show that Exxon’s actions were unreasonable. The court stated:

In fact, the State presented testimony from Duane Bordvick regarding the risk-benefit analysis his company, Tosco — another manufacturer during the relevant time period of this case — conducted. Bordvick testified that Tosco decided not to use MTBE because of the unique and increased risks Tosco perceived MTBE to have. This testimony not only directly contradicts Exxon’s argument that the State failed to show the care exercised by other members of the refining industry, it also serves as some evidence from which a jury could conclude that Exxon’s behavior in selecting MTBE as its RFG formula oxygenate and doing so without providing a warning was unreasonable.

(Citations omitted.) The trial court also rejected, as unsupported by the record, Exxon’s argument that it could not have foreseen all manner in which the State’s alleged harm occurred. The court stated:

The State admitted Barbara Mickelson’s memorandum to Exxon that demonstrates Exxon received warnings against the use of MTBE — that MTBE would take longer and cost more to remediate than traditional gasoline spills. Other witnesses corroborated Exxon’s possession of information regarding the expense associated with MTBE remediation as early as the 1980s. In this way, a reasonable jury could conclude that Exxon should have foreseen the harm the State now alleges — increased remediation costs of a different nature than those associated with traditional gasoline.

(Citations omitted.)

Following the jury verdict, Exxon moved for JNOV, arguing, in part, that “there is no evidence in the record regarding the standard of care for a reasonably prudent refiner or manufacturer or what actions ExxonMobil took that breached a standard of care” when the decision to use MTBE was made. Exxon asserted that it presented testimony showing that it “carefully considered the use of MTBE,” including consulting with “[a]t least nine different groups within Exxon” to gain information, and that “[ojther *235gasoline refiners and manufacturers agreed with Exxon’s assessment that the RFG program’s requirements could not have been met without the use of MTBE in addition to ethanol.” Noting that it had previously rejected Exxon’s arguments in its directed verdict ruling, the trial court relied upon that ruling in declining to consider these arguments again “[bjecause Exxon raises no new facts or law.”

On appeal, Exxon argues that the State “offered no evidence to support the notion that a reasonable supplier in New Hampshire would never have used ..MTBE at any time” and that “[w]ithout a relevant standard against which to compare Exxon’s conduct, the State’s negligence claim ... fails as a matter of state law.” According to Exxon, the State failed to establish that it departed from the applicable standard of care simply by marketing MTBE, asserting that “the evidence presented at trial showed that manufacturers overwhelmingly complied with the RFG program in the Northeast by using MTBE because there was no safer, feasible alternative.” The State argues that “[t]he record contains ample evidence that Exxon breached the standard of care,” the trial court properly instructed the jury regarding the duty of care, and the jury found Exxon negligent.

Weighing the evidence is a proper function of the factfinder. 93 Clearing House, Inc. v. Khoury, 120 N.H. 346, 350 (1980). The trier of fact is in the best position to measure the persuasiveness of evidence and the credibility of witnesses. Id. Factual findings “will not be disturbed unless-... erroneous as a matter of law or unsupported by the evidence.” Great Lakes Aircraft Co. v. City of Claremont, 135 N.H. 270, 287 (1992) (quotations omitted); see Sutton v. Town of Gilford, 160 N.H. 43, 55 (2010). “A fact finder has the discretion to evaluate the credibility of the evidence and may choose to reject that evidence in whole or in part.” Society Hill at Merrimack Condo. Assoc. v. Town of Merrimack, 139 N.H. 253, 256 (1994). Our task is to determine whether a reasonable person could reach the same conclusion as the jury on the basis of the evidence before it. See Shaka v. Shaka, 120 N.H. 780, 782 (1980). We review sufficiency of the evidence claims as a matter of law. Tosta v. Bullis, 156 N.H. 763, 767 (2008).

The test of due care is what reasonable prudence would require under similar circumstances. Carignan v. N.H. Int’l Speedway, 151 N.H. 409, 414 (2004). Whether the defendant breached that duty of care is a question for the trier of fact. Id. “[N]ot every risk that might be foreseen gives rise to a duty to avoid a course of conduct; a duty arises because the likelihood and magnitude of the risk perceived is such that the conduct is unreasonably dangerous.” Millis v. Fouts, 144 N.H. 446, 449 (1999) (quotation omitted). “[Conformity with industry practice is not an absolute defense to liability under New Hampshire law, because entire industries *236may lag behind the standard of care. But it is nonetheless a factor that the jury may consider in evaluating negligence claims.” Bartlett v. Mutual Pharmaceutical Co., Inc., 742 F. Supp. 2d 182, 189 (D.N.H. 2010) (quotation and citation omitted); see Bouley v. Company, 90 N.H. 402, 403 (1939) (the test of due care is not custom or usage, but what reasonable prudence would require under the circumstances).

The record supports that in April 1984, an Exxon employee stated in an internal memo that “we have . . . ethical and environmental concerns [about MTBE] that are not too well defined at this point.” The memo explained that as there were “strong economic incentives to use MTBE, a study should be started [to] thoroughly review the issues with management.” In August 1984, Exxon asked an in-house environmental engineer, Barbara Mickelson, for “information on additional potential ground water contamination problems that are associated with the use of MTBE in gasoline.” Mickelson stated that “MTBE when dissolved in ground water, will migrate farther than [another gasoline additive] before soil attenuation processes stop the MTBE migration.” She explained that the “[s]mall household carbon filtration units . . . used by Exxon to treat private drinking supplies contaminated by [another gasoline additive]... would not provide adequate treatment for water supplies additionally contaminated by MTBE.” Mickelson concluded that “the number of well contamination incidents is estimated to increase three times following the widespread introduction of MTBE into Exxon gasoline” and that “the closing-out of these incidents would take longer and treatment costs would be higher by a factor of 5.” In 1985, Mickelson recommended that “from an environmental risk point of view MTBE not be considered as an additive to Exxon gasolines on a blanket basis throughout the United States” because of its unique contaminating properties.

In the 1980s, Exxon joined the MTBE Committee, an industry group that was formed to address “environmental issues” and “federal and state regulatory issues” relating to MTBE. In a December 1986 meeting with MTBE Committee members, including Exxon, the EPA expressed concern about MTBE leaking into groundwater because MTBE, “which is very soluble in water, can find its way to drinking supplies (i.e. acqu[i]fers).” Nonetheless, in February 1987, the MTBE Committee represented to the EPA that

there is no evidence that MTBE poses any significant risk of harm to health or the environment, that human exposure to MTBE and release of MTBE to the environment is negligible, that sufficient data exists to reasonably determine or predict that manufacture, processing, distribution, use and disposal of MTBE will not have *237an adverse effect on health or the environment, and that testing is therefore not needed to develop such data.

After Congress amended the Clean Air Act in 1990 to require use of an oxygenate in gasoline, members of the American Petroleum Institute, an industry lobbying group that included Exxon, met with New Hampshire officials and encouraged them to opt in to the RFG Program. During those meetings, it was not disclosed that oil companies would use MTBE in RFG Program gasoline. Robert Varney, who was the commissioner of DES during the relevant time, testified that, although Exxon knew as early as 1984 about MTBE groundwater contamination issues, Exxon did not warn the State or provide it with any information about those issues before Varney recommended that the State opt in to the RFG Program in 1991 or before he recommended that it remain in the Program in 1997. He also testified that the State would not have opted in to the RFG Program if DES had known the information contained in Miekelson’s 1984 memo.

In 1999, Exxon had identified more than 100 known contamination sites in New England, many polluted solely with MTBE. That same year, a study by Exxon on the costs of cleaning up MTBE noted that spills containing MTBE could be more difficult and costly to clean up because MTBE “is more soluble [in water] and less biodegradable than other gasoline components.” The study found that “[c]ost increases related to MTBE are significant for ... New England” due in part to “hydrogeologic site conditions which maximize the potential for MTBE to ‘travel’ and impact receptors (e.g., shallow groundwater, fractured bedrock, a high density of private potable wells).” In 2000, Exxon employees observed in an internal communication that “industry has not demonstrated the ability to stop leaks and spills to the level required to avoid MTBE concentrations that effect [sic] the taste and odor in drinking water,” that “non MTBE fuel leaks are more managable [sic],” and that “[b]ased on experience in [the] US, it is fair to assume that other places using MTBE will eventually find groundwater contamination.”

Duane Bordvick, a former senior vice-president for safety, health and environment at Tosco Corporation, a gasoline refinery in California, testified that in 1997 he made a statement on behalf of Tosco that the company had decided “that long-term use of MTBE was not in the best interest of’ the company or its shareholders due to the “potential threat to California’s drinking water resources and the associated liability ... for restoring water resources.” He testified that that conclusion was drawn based upon several factors including: “the growing evidence on the threat of MTBE contamination and evidence related to the difficulty of cleaning up MTBE”; “the cost associated [with] potentially having to participate in replacement of drinking water to cities”; “the potential liability for the use *238of MTBE, associated legal costs, [and] potential lawsuits that may result”; and the “likelihood” that those costs “would exceed ... whatever costs may be associated with no longer relying on MTBE in [Tosco’s] gasoline,” including refinery changes and other equipment changes.

As the trial court instructed the jury:

Negligence is the failure to use reasonáble care. Reasonable care is the degree of care that an ordinary, prudent manufacturer or supplier would use under the same or similar circumstances.

The failure to use reasonable care may take the form of action or inaction. That is, negligence may consist of either: doing something that an ordinary, prudent manufacturer or supplier would not do under the same or similar circumstances; or, failing to do something that an ordinary, prudent manufacturer or supplier would do under the same or similar circumstances.

A manufacturer or supplier has a duty to make inspections or tests that are reasonably necessary to see that its product is safe for its intended use and for any other reasonably foreseeable purpose.

Viewed in the light most favorable to the State, we hold that the record contains sufficient evidence to support a finding that Exxon breached the standard of care by acting unreasonably under the circumstances. Accordingly, we uphold the trial court’s rulings.

VI. Duty to Warn

Exxon argues that it did not have a duty to warn the government as sovereign, rather than as end user or consumer, of the characteristics of MTBE gasoline. In 2008, Exxon moved to dismiss the State’s failure-to-warn claim, alleging that when the State claims that, as a bystander, it is a consumer of MTBE, and is therefore entitled to bring a products liability claim, it improperly expands the definition of “consumer,” and that the State should be classified as a third party bystander. Because New Hampshire does not recognize bystander liability claims, Exxon argued that the State’s strict liability claims should be dismissed.

The trial court denied the motion, finding that the State’s claim regarding Exxon’s alleged failure to warn of its defective product had been properly pleaded. Based upon RSA 481:1 (2013), the court concluded that because the State “holds the waters of New Hampshire in trust for the public,” the State had properly alleged that “the defendants may be sought to be held liable for damage to the State’s waters.” The trial court rejected the argument that “the State’s interests in its water are akin to those of a *239bystander.” Several years later, Exxon moved for summary judgment on the State’s failure-to-warn claim, arguing that because the State was not a “user” or “consumer” of MTBE it “cannot premise a failure-to-warn claim on [Exxon’s] alleged failure to warn the State itself.” The trial court agreed with the State that the issue had already been addressed in the prior order on the motion to dismiss.

In its motion for a directed verdict at the close of the State’s case-in-chief, Exxon argued, in part, that the State “failed to introduce evidence that ExxonMobil failed to warn ‘users’ of gasoline containing MTBE, instead focusing exclusively on ExxonMobil’s alleged failure to warn the State as a regulatory entity, not as a user.” The trial court rejected Exxon’s arguments, stating that “the State is the party who — if a jury determined a warning was required — would have been owed the warning.” The court explained that “[t]he State, as the consumer and in its parens patriae capacity, was an end user of MTBE gasoline. This Court has previously ruled the State has standing to assert claims brought on behalf of the people of New Hampshire. Additionally, the State is a consumer itself.”

On appeal, Exxon argues that “[t]he theory that there is a duty to warn the sovereign qua sovereign” is “wholly unprecedented, oversteps longstanding limitations of New Hampshire tort law, and raises serious First Amendment difficulties.” The State argues that “although Exxon contends that the verdict hinges on the State’s status as sovereign, the trial evidence clearly demonstrated that Exxon provided no warning about MTBE to anyone” and that Exxon, thus, “failed to warn the State as regulator, the State as an end user, or the citizenry represented by the State as parens patriae.” We agree with the State.

The General Court has declared that the State is the trustee over all of the State’s water. Pursuant to RSA 481:1,

an adequate supply of water is indispensable to the health, welfare and safety of the people of the state and is essential to the balance of the natural environment of the state. Further, the water resources of the state are subject to an ever-increasing demand for new and competing uses. The general court declares and determines that the water of New Hampshire whether located above or below ground constitutes a limited and, therefore, precious and invaluable public resource which should be protected, conserved and managed in the interest of present and future generations. The state as trustee of this resource for the public benefit declares that it has the authority and responsibility to provide careful stewardship over all the waters lying within its boundaries.

*240RSA 481:1. As trustee, the State can bring suit to protect from contamination the waters over which it is trustee. Hess, 161 N.H. at 432.

In State v. City of Dover, 153 N.H. 181 (2006), we determined that the State was the proper party to bring suit against the MTBE defendants, because it “has a quasi-sovereign interest in protecting the health and well-being, both physical and economic, of its residents with respect to the statewide water supply.” City of Dover, 153 N.H. at 186. In addition, we concluded that the State satisfied the requirements of parens patriae standing because it asserted an injury to a quasi-sovereign interest, and alleged injury to a substantial segment of its population. Id. at 187-88. “[A] state may act as the representative of its citizens where the injury alleged affects the general population of a State in a substantial way.” Hess, 161 N.H. at 433 (quotation omitted). Accordingly, we held that the State has parens patriae standing to bring suit against the MTBE defendants on behalf of the residents of New Hampshire. City of Dover, 153 N.H. at 187-88.

The jury was not instructed that Exxon owed a duty to the State as sovereign. Rather, the trial court instructed:

In deciding whether there was a design defect in the product, you may consider whether there was a warning, and, if so, whether the warning was adequate. The warning is inadequate unless it makes the potential harmful consequences apparent and contains specific language directed at the significant risks or dangers caused by a failure to use the product in the prescribed manner. The manner of the warning is inadequate unless it is of such intensity to cause a reasonable person to exercise caution equal to the potential danger.

The State has the burden to prove that if ExxonMobil had provided an adequate warning, MTBE gasoline would not have been used or would have been used differently.

A failure to warn amounts to a legal cause of harm when the failure to warn is a substantial factor in bringing about the harm, and if the harm would not have occurred without the failure to warn. The failure to warn need not be the only cause of the injury, but it must be a substantial factor in bringing about the injury.

We reject Exxon’s argument that the State’s failure-to-warn claim was improper because it was premised upon a duty to warn the “sovereign qua sovereign.” Accordingly, we find no error.

*241 VII. Market Share Liability

Exxon argues that market share liability is not an acceptable theory of recovery and, that, even if it is, the trial court erred in applying market share liability in this case. Several years before trial, Exxon sought an order requiring the State to specify “which Defendants it seeks to hold liable for the damages,” “what damages it seeks to recover from those Defendants and when and how the damages occurred,” and “the legal theory for holding those Defendants liable for the damages.” (Quotations omitted.) The trial court denied the motion, finding that

requiring the State to allege specifically which defendant caused each injury would create an impossible burden given the allegations of commingling of MTBE and the asserted indivisible injury to the State of New Hampshire’s water supplies. To mandate the State to establish more particularized causation would essentially allow the defendants to seek to avoid liability because of lack of individualized proofs where the gravamen of the claim is ... that all defendants placed gasoline containing MTBE into the stream of commerce, thereby causing [the State’s] injury.

To allow such a state of events would be to allow claims for tortious conduct for discrete, identifiable, and perhaps lesser tortious acts, but to deny claims for tortious conduct where the conduct alleged may be part of group activity which is alleged [to] have led to a common, and more deleterious, result.

(Quotation omitted.)

In a subsequent order, the trial court, recognizing that “situations exist where a plaintiff may not necessarily be able to identify, specifically, which members of a group, who are engaged in the same activity, caused his or her damages,” noted that courts “allow plaintiffs to prove causation through alternative theories of liability,” including market share liability and “seemingly specific to the MTBE cases, . . . commingled product theory.” The court found that the “commingled product theory” does not apply here because that theory “only relieves the Plaintiff of its burden to prove the percentage of a particular Defendant’s gasoline found at a particular site,” and the court “has already found that a specific site-by-site approach is unfeasible and unnecessary in this case.” Accordingly, the trial court concluded that market share liability “is a more reasoned approach to this case.”

As the trial court explained, the purpose behind market share liability is that

*242[i]n our contemporary complex industrialized society, advances in science and technology create fungible goods which may harm consumers and which cannot be traced to any specific producer. The response of the courts can be either to adhere rigidly to prior doctrine, denying recovery to those injured by such products, or to fashion remedies to meet these changing needs. In an era of mass production and complex marketing methods the traditional standard of negligence is insufficient to govern the obligations of manufacturer to consumer; courts should acknowledge that some adaptation of the rules of causation and liability may be appropriate in these recurring circumstances.

(Quotation, ellipsis, and brackets omitted.) The court noted that in determining whether market share liability applies in certain circumstances, the Restatement (Third) of Torts: Products Liability sets forth six factors that provide a general framework for analysis:

(1) The generic nature of the product; (2) the long latency period of the harm; (3) the inability of plaintiffs to discover which defendant’s product caused plaintiffs harm; (4) the clarity of the causal connection between the defective product and the harm suffered by plaintiffs; (5) the absence of other medical or environmental factors that could have caused or materially contributed to the harm; and (6) the availability of sufficient “market share” data to support a reasonable apportionment of liability.

(Quotation and ellipsis omitted.) See Restatement (Third) of Torts: Products Liability § 15 comment c at 233 (1998). The court found that in this case “these factors weigh heavily in favor of utilizing market share liability.”

Exxon subsequently moved for summary judgment on the issue of causation, asserting that New Hampshire has not adopted the market share liability theory, and that “the theory is contrary to New Hampshire law.” The trial court concluded, however, that New Hampshire recognizes market share liability. Citing Buttrick v. Lessard, 110 N.H. 36 (1969), and Trull v. Volkswagen of America, 145 N.H. 259 (2000), the court reasoned that “[t]he New Hampshire Supreme Court has repeatedly expressed its willingness to provide plaintiffs with a less stringent burden of proof where they face a ‘practically impossible burden,’ ” and that “[gjiven this willingness, the court is confident that existing New Hampshire law supports the application of Market-Share Liability.” Dismissing as unfounded Exxon’s suggestion that market share liability “is synonymous with absolute liability,” the trial court explained that

*243[e]ven where a plaintiff proceeds under a Market-Share Liability theory, he must prove that the defendants breached a duty to avoid an unreasonable risk of harm from their products .... The requirement to prove that a defendant breached his duty to avoid harm is a separate and distinct burden. Only after a plaintiff makes such a showing is he entitled to a relaxed standard for proving causation.

(Quotation and citation omitted.)

Applying the six Restatement factors, the trial court determined that market share liability should be applied in this case. As to the first factor, the generic nature of the product, the court found that the State had alleged sufficient facts for the court to conclude that MTBE is fungible, ie., that it is interchangeable with other brands of the same product. As to the second factor, whether the harm caused by the product has a long latency period, the trial court found that the harm caused by MTBE was not latent because it travels faster and further than other chemicals. Thus, the court concluded that this factor weighs in favor of Exxon. As to the third factor, the plaintiffs inability to identify which defendant caused the harm, the trial court concluded this factor weighs in the State’s favor because “retailers commingled gasoline in storage tanks at stations, so it would be impossible to determine which of the defendants’] MTBE gasoline was discharged into the environment.”

The trial court found that the fourth factor, the clarity of the causal connection between the defective product and harm suffered by the State, favors the State. The court agreed with Exxon’s general proposition that the gasoline market does not alone reflect the risk created and, thus, the court required the State “to introduce market share data as targeted as possible (e.g. market share data specific to RFG and non-RFG counties).” (Quotation omitted.) Noting that it is impossible to determine market share with mathematical exactitude, the court concluded that the experts’ market data was sufficient.

The trial court found the fifth and sixth factors favor the State. As to the fifth factor, whether other medical or environmental factors could have contributed to the harm, the court noted that Exxon had not asserted that other factors contributed. As to the sixth factor, the sufficiency of the market data, the court found that the State’s experts had presented “enough market data to allow the State to proceed” on a market share liability theory.

Following the jury verdict, Exxon moved for JNOY, arguing, in part, that, for five reasons, the market share liability evidence the jury considered was insufficient for the jury to find it liable: (1) there was no evidence *244that Exxon’s market share for MTBE gasoline was 28.94% because that figure measured all gasoline supplied in New Hampshire; (2) there was no evidence to support the jury’s finding that all gasoline containing MTBE was fungible; (3) no rational trier of fact could have found that the State could not trace MTBE gasoline back to the company that supplied it because, from 1996 to 2005, the State could identify the suppliers that caused its alleged harm; (4) the State failed to identify a substantial segment of the relevant market for gasoline containing MTBE because it only presented evidence as to “a snapshot of’ the wholesale market; and (5) the State failed to establish the relevant market at the time of its alleged injuries. Noting that Exxon had raised, and the court had rejected, all of these arguments before, and because Exxon raised no new law or facts to support its motion, the court addressed Exxon’s arguments “only for the purpose of further explanation and clarification.”

Considering Exxon’s first and fifth arguments together, the court determined that “the State presented sufficient evidence for a reasonable juror to conclude that all gasoline imported into New Hampshire was commingled with MTBE gasoline. From there, the jury could reasonably have assigned Exxon the share of the gasoline market that its supply represented.” With respect to Exxon’s second argument, the court concluded that there was “sufficient evidence from which a reasonable jury could find that MTBE gasoline was fungible.” As to Exxon’s third and fourth arguments, the court noted that the State “presented evidence through various witnesses from which a juror could reasonably conclude that all gasoline in New Hampshire was statistically likely to be commingled with MTBE to some concentration. Thus, it was for the jury to decide whether it would rely upon the 100 percent figure [the State’s expert] provided, or a lower figure.” The court also observed that it had previously found the State’s expert qualified, and that her testimony “was based upon sufficient facts and data; her testimony was the product of reliable principles and methods; and she applied the principles and methods reliably to the facts of the case.” Finally, the trial court addressed Exxon’s additional argument that, because MTBE gasoline could be traced to a supplier from the refinery, the State failed to prove its market share case. The court stated:

The State’s theory of the case, as addressed in pretrial, trial, and directed verdict rulings, was that MTBE gasoline is untraceable once spilled or leaked; once it causes harm to the State. It is wholly irrelevant that gasoline might be traceable to a particular supplier from a wholesale distributor or even the refinery because, as the State alleged, once the gasoline causes harm, it cannot be traced to a supplier, distributor, or refiner. The jury *245heard evidence to this extent, and could thereby have found that the State met the requisites of relying on market share liability for causation purposes.

Exxon also moved to set aside the verdict and for a new trial arguing, in part, that the trial court erred as a matter of law by allowing the State to use market share liability. Exxon argued that the State “should have been compelled ... to proceed on a site-specific basis and rely on traditional causation to prove its claims,” and that it was error “to permit the State to use a wholesale supplier market share when it was undisputed that... the MTBE gasoline that allegedly caused the State’s harm could be traced back to the wholesale suppliers, thus negating the need for or applicability of [market share liability] theories.” The trial court rejected Exxon’s arguments. As to Exxon’s argument that the jury needed to find first that the State could not prove traditional causation in order to find the State entitled to rely upon market share liability, the trial court stated that market share liability “did not require the State to prove that it could not establish traditional causation; it required the State to show that it could not identify the tortfeasor responsible for its injury. The ‘last resort’ requirement focuses on the inability of the plaintiff to identify the manufacturer of a product, not the absence of alternative causes of action or theories of recovery.” The court concluded:

During trial, the State presented several witnesses who testified that MTBE gasoline is fungible and commingled at nearly every step in the distribution network, thereby making it virtually, impossible if not impossible to trace from a spill or leak back from a contamination site to a retailer or supplier. This testimony tended to fulfill the State’s burden of proving that it was unable to identify the specific tortfeasor responsible for its injury. The jury’s verdict — finding that the State was unable to identify the specific tortfeasor responsible for its injury — was not conclusively against the weight of the evidence.

(Citations omitted.)

On appeal, Exxon argues that the trial court erred in adopting market share liability in New Hampshire because it “departs from centuries of New Hampshire law.” Exxon also argues that “[e]ven if market share liability would ever be appropriate under New Hampshire law, this would be a poor case to make that first jump” and that the trial court “applied the wrong market share.” The State argues that traditional principles of tort law support the use of market share evidence, that Exxon has failed to show that market share liability was not warranted on the facts of this case, and *246that the trial court properly ruled that the jury was entitled to determine that Exxon should be held liable for its percentage of the supply, rather than the refining market.

We review challenges to a trial court’s evidentiary rulings under our unsustainable exercise of discretion standard and reverse only if the rulings are clearly untenable or unreasonable to the prejudice of a party’s case. In the Matter of McArdle & McArdle, 162 N.H. 482, 485 (2011). We review questions of law de novo. Sanderson v. Town of Candia, 146 N.H. 598, 600 (2001).

Market share liability has its roots in a 1980 decision of the California Supreme Court, Sindell v. Abbott Laboratories, 607 P.2d 924 (Cal. 1980). In Sindell, the plaintiffs alleged injuries resulting from their in útero exposure to the drug diethylstilbesterol (DES), a synthetic hormone that was marketed to women as a miscarriage preventative from 1947 to 1971. Sindell, 607 P.2d at 925. In 1971, a link was discovered between fetal exposure to DES and the development many years later of adenocarci-noma. Id. Over 200 manufacturers made DES and, because of the long latency period and generic nature of the drug, many plaintiffs were unable to identify the precise manufacturer of the DES ingested by their mothers during pregnancy. Id. at 931. Plaintiff Sindell brought a class action against 11 drug manufacturers, alleging that the defendants were jointly and severally liable because they had acted in concert to make, market, and promote DES as a safe and effective drug for preventing miscarriages. Id. at 925-26. The trial court had dismissed the claims due to Sindell’s inability to identify which defendants had manufactured the DES responsible for her injuries. Id. at 926.

In reversing that decision, the California Supreme Court expanded alternative liability to encompass what is now known as market share liability. Under market share liability, the burden of identification shifts to the defendants if the plaintiff establishes a prima facie case on every element of the claim except for identification of the actual tortfeasors, and the plaintiff has joined the manufacturers of a “substantial share” of the DES market. Id. at 936-37. Once these elements are established, each defendant is severally liable for the portion of the judgment that represents its share of the market at the time of the injury, unless it proves that it could not have made the DES that caused the plaintiffs injuries. Id. at 937.

The court based its decision upon two considerations: (1) “as between an innocent plaintiff and negligent defendants, the latter should bear the cost of the injury”; and (2) “[f]rom a broader policy standpoint,” because the manufacturer “is in the best position to discover and guard against defects in its products and to warn of harmful effects ..., holding it liable ... will *247provide an incentive to product safety.” Id. at 936. The court held it to be reasonable, in the context of the case, “to measure the likelihood that any of the defendants supplied the product which allegedly injured plaintiff by the percentage which the DES sold by each of them ... bears to the entire production of the drug sold by all for that purpose.” Id. at 937. By holding each defendant liable for the proportion of the judgment represented by its share of the market, “each manufacturer’s liability would approximate its responsibility for the injuries caused by its own products.” Id.

Several states have adopted some form of market share liability. See, e.g., Collins v. Eli Lilly Co., 342 N.W.2d 37, 49-51 (Wis. 1984) (adopting a form of market share liability in DES case); Martin v. Abbott Laboratories, 689 P.2d 368, 380-82 (Wash. 1984) (rejecting Sindell market-share theory of liability in favor of market-share alternative liability in DES case); Hymowitz v. Eli Lilly and Co., 539 N.E.2d 1069, 1075-78 (N.Y. 1989) (adopting market share liability theory for a national market in DES case); Conley v. Boyle Drug Co., 570 So. 2d 275, 285-86 (Fla. 1990) (adopting market share alternate liability theory in DES case); Smith v. Cutter Biological, Inc., 823 P.2d 717, 727-29 (Haw. 1991) (adopting market share liability theory in action against manufacturers of blood product). In other jurisdictions, courts have left open the possibility of adopting market share liability in the future. See, e.g., Skipworth v. Lead Industries Ass’n, Inc., 690 A.2d 169, 172 (Pa. 1997) (deciding not to adopt market share liability in lead paint case, but recognizing that the need to adopt that theory might arise in the future); Shackil v. Lederle Laboratories, 561 A.2d 511, 529 (N.J. 1989) (decision “should not be read as forecasting an inhospitable response to the theory of market-share liability in an appropriate context”); Case v. Fibreboard Corp., 743 P.2d 1062, 1066-67 (Okla. 1987) (rejecting market share liability in asbestos case but recognizing that market share considerations were sufficient in DES context to achieve a balance between the rights of the defendants and the rights of the plaintiffs); Payton v. Abbott Labs, 437 N.E.2d 171, 190 (Mass. 1982) (court might recognize “some relaxation of the traditional identification requirement in appropriate circumstances so as to allow recovery against a negligent defendant of that portion of a plaintiffs damages which is represented by that defendant’s contribution of DES to the market in the relevant period of time”); see Abel v. Eli Lilly and Co., 343 N.W.2d 164, 173-74 (Mich. 1984) (a “new DES-unique version of alternative liability” will be applied in cases in which all defendants have acted tortiously, but only one unidentifiable defendant caused plaintiffs injury).

We disagree with Exxon that the trial court erred in concluding that New Hampshire would recognize market share liability as an alternative *248liability theory and that the theory is proper on the facts of this case. In Buttrick v. Lessard we adopted strict liability for design defect claims because requiring the plaintiff to prove negligence would impose “an impossible burden” on the plaintiff due to the difficulty of proving breach of a duty by a distant manufacturer using mass production techniques. Buttrick, 110 N.H. at 39. We explained:

The rule requiring a person injured by a defective product to prove the manufacturer or seller negligent was evolved when products were simple and the manufacturer and seller generally the same person. Knowledge of the then purchaser . . . was sufficient to enable him to not only locate the defect but to determine whether negligence caused the defect and if so whose. The purchaser of the present day is not in this position. How the defect in manufacture occurred is generally beyond the knowledge of either the injured person or the marketer or manufacturer.

Id. As we later noted, what was crucial to our policy analysis in Buttrick “was the recognition that the need to establish traditional legal fault in certain products liability cases had proven to be, and would continue to be, a practically impossible burden. This was the compelling reason of policy without which Buttrick would have gone the other way.” Bagley v. Controlled Environment Corp., 127 N.H. 556, 560 (1986) (citations and quotation omitted).

Based upon this rationale, we subsequently placed the burden of proving apportionment upon defendants in crashworthiness or enhanced injury cases involving indivisible injuries. Trull, 145 N.H. at 260. In Trull, we held that plaintiffs were required to prove that a design defect was a substantial factor in producing damages over and above those caused by the original impact to their car, and, once they had made that showing, the burden would shift to the defendants to show which injuries were attributable to the initial collision and which to the design defect. Id. at 265. That burden was placed upon the defendants because the plaintiffs would otherwise have been “relegated to an almost hopeless state of never being able to succeed against a defective designer.” Id. (quotation omitted). We were persuaded by policy reasons not to place a “practically impossible burden” upon injured plaintiffs. Id.

By contrast, we have declined to expand products liability law in cases in which plaintiffs have not faced a practically impossible burden of proving negligence. See, e.g., Royer v. Catholic Med. Ctr., 144 N.H. 330, 335 (1999) (strict liability did not apply to tort action against non-manufacturer hospital for selling defective prosthetic knee to plaintiff); Bruzga v. PMR *249 Architects, 141 N.H. 756, 761 (1997) (unlike a consumer who purchases a mass-produced good, strict liability does not apply to architect and contractor because the owner or user of a building does not face “extraordinary difficulties in proving liability under traditional negligence principles”); Bagley, 127 N.H. at 560 (declining to impose strict liability in action by landowner against adjoining landowner for damages resulting from soil and groundwater contamination because “there [was] no apparent impossibility of proving negligence”); Siciliano v. Capitol City Shows, Inc., 124 N.H. 719, 730 (1984) (refusing to extend strict liability to owner and operator of amusement park ride when there was no indication that the plaintiffs suffered an “unfair burden” from not doing so because they possess adequate protection through an action for negligence); Wood v. Public Serv. Co., 114 N.H. 182, 189 (1974) (no “compelling reason of policy or logic” advanced to apply strict liability to electric companies in wrongful death action).

We have also declined to expand products liability law when the defendants could not have been at fault. Simoneau v. South Bend Lathe, Inc., 130 N.H. 466 (1988). In Simoneau, we rejected the product line theory of successor liability, reasoning that “liability without negligence is not liability without fault.” Id. at 469. Under the product line theory, a party that acquires a manufacturing business and continues the output of its line of products, assumes strict liability for defects in units of the same product line manufactured and sold by the predecessor company. Id. at 468. We refused to “impose what amounts to absolute liability on a manufacturer,” id. at 470, reaffirming “[t]he common-law principle that fault and responsibility are elements of our legal system applicable to corporations and individuals alike” and that such principle ought “not be undermined or abolished by spreading of risk and cost in this State.” Id. at 469 (quotation omitted).

Based upon the reasoning expressed in our cases developing products liability law in New Hampshire, the trial court concluded that it would “not rigidly apply theories of tort law where doing so would either be impractical or unfairly ‘tilt the scales’ in favor of one party or another.” We agree with the trial court that, based upon our willingness to construct judicial remedies for plaintiffs who would be left without recourse due to impossible burdens of proof, applying market share liability was justified in the circumstances presented by this case. In addition to finding that the State had proven all of the elements of its claims, the jury found: “MTBE gasoline is fungible”; the State “cannot trace MTBE gasoline found in groundwater and in drinking water back to the company that manufactured or supplied that MTBE gasoline”; and the State “has identified a substan*250tial segment of the relevant market for gasoline containing MTBE.” We have reviewed the record and conclude that it contains sufficient evidence to support the jury’s findings. Given the evidence presented, the State faced an impossible burden of proving which of several MTBE gasoline producers caused New Hampshire’s groundwater contamination. We hold that the trial court did not unsustainably exercise its discretion in allowing the State to use the theory of market share liability to determine the portion of the State’s damages caused by Exxon’s conduct.

Exxon argues that because the trial court found that there was sufficient evidence for the State to prove traditional causation, it erred by instructing the jury on market share liability. We disagree. To the contrary, the trial court merely found that the State could prove “but for” causation as required under the market share liability theory. “Under market share liability, the burden of identification shifts to the defendants if the plaintiff establishes a prima facie ease on every element of the claim except for identification of the actual tortfeasor or tortfeasors ...” In re Methyl Tertiary Butyl Ether Products Liab., 379 F. Supp. 2d 348, 375 (S.D.N.Y.2005). Exxon argued in its motion for a directed verdict at the close of the State’s case-in-chief that, “[f]or each of the State’s claims, the State was required to provide evidence specific to ExxonMobil that gasoline containing MTBE from ExxonMobil was the but for cause of the State’s alleged injuries and that ExxonMobil’s conduct or product were a substantial factor in bringing about the State’s alleged injuries.” Exxon asserted that such proof “was utterly lacking . . . and the State has not identified any evidence that gasoline containing MTBE from ExxonMobil caused any of the alleged contamination in this case under traditional theories of causation.”

The trial court denied Exxon’s motion, reasoning that, from testimony presented by the State, “a reasonable jury could conclude that Exxon was the proximate cause of the State’s alleged injury under a traditional causation theory.” Thus, the trial court rejected Exxon’s argument that the State had not established a prima facie case on each of its claims. Further, the evidence established that MTBE gasoline is a fungible product, that the fungibility of MTBE gasoline allows it to be commingled at nearly every step of the gasoline distribution system, and that commingling prevents the State from tracing a molecule of MTBE gasoline from the refinery to New Hampshire so that the State cannot identify the refiner of the MTBE gasoline that caused the harm. Thus, because the State could not identify the tortfeasor responsible for its injury, under market share liability the burden of identification shifted to Exxon. Accordingly, the jury was instructed:

*251If the State has been harmed by a product that was manufactured and sold by any number of manufacturers and suppliers, and the State has no reasonable means to prove which manufacturer or supplier supplied the product that caused the injury, then the State may use market share liability to satisfy its burden of proof. Under market share liability, ExxonMobil is responsible for the State’s harm in proportion to ExxonMobil’s share of the market for the defective product during the time that the State’s harm occurred.

Market share liability requires that the State . .. prove all the elements for negligence, or strict liability defect in design, or strict liability based on a failure to warn and that the State suffered harm. In addition, the State must prove the following: (1) it has identified enough MTBE gasoline manufacturers or suppliers in this case so that a substantial share of the relevant market is accounted for; and (2) MTBE gasoline is fungible, meaning that one manufacturer’s or supplier’s MTBE gasoline is interchangeable with another’s; and (3) the State cannot identify the manufacturer or supplier of the MTBE gasoline that caused the harm.

Finally, we find no error with the trial court’s ruling that the jury was entitled to determine that Exxon could be held liable for its percentage of the supply market. As the trial court reasoned, because Exxon “had or should have had knowledge of the characteristics of MTBE gasoline from [its] refining role[ ],” a jury could find Exxon liable for MTBE gasoline it supplied but did not refine. The trial court explained that the jury was entitled to estimates of supplier and refiner market share and that both reflected Exxon’s “creation of the risk within the State,” and that “[a]ny figure within this spectrum would be an appropriate measure of the State’s damages.”

VIII. Aggregate Statistical Evidence

Exxon argues that the State should not have been permitted to rely upon aggregate statistical evidence rather than individualized evidence of particular water supplies and sites. Before trial, Exxon moved to exclude the opinions of three of the State’s experts estimating the probability of MTBE occurrence in New Hampshire, the past costs of MTBE remediation, and the future costs of investigating and remediating MTBE sites. Exxon argued that these experts, Dr. Graham Fogg, Gary Beckett, and Dr. Ian Hutchison, “attempt to draw statewide conclusions about MTBE detections *252and costs from small ‘sample’ datasets, extrapolating to the State at large,” but “fail ... to follow basic, well-accepted statistical and scientific principles.”

Following a hearing, the trial court issued a written order “accepting] the [State’s] argument that using statistical methods is appropriate and, as a result, the state-wide proof model is acceptable and relevant.” The court reasoned that “the use of statistical methods, assuming their reliability, makes the existence of the [State’s] injury more probable than it would be without such evidence; likewise, it will assist the trier of fact to understand and determine both the existence and extent of the [State’s] injury.” Thus, the trial court concluded that the State’s experts’ opinions “are relevant to prove injury-in-fact and damages” and that it would accept proof of injury “through the use of statistical evidence and extrapolation, i.e. the ‘statewide approach.’ ”

The trial court set forth several reasons in support of its conclusion. First, the court noted that the majority of the cases cited by Exxon are class-action cases, “which disallow the use of aggregate damages across a class of plaintiffs.” The court found those cases distinguishable because, here, the State “does not seek to establish injury among several class plaintiffs through the use of an aggregate model, but instead seeks to prove its own injury through the use of statistics.” Second, the court reasoned that New Hampshire’s “ ‘declaration of policy’ confirms that an injury to both public and private waters within the [s]tate is an indivisible injury, allowing for the State to prove its claim upon state-wide proof.” The court stated that under RSA 481:1, “[t]he state as trustee of the waters for the public benefit declares that it has the authority and responsibility to provide careful stewardship over all the waters lying within its boundaries,” and that this statute provides the State “with more than just a vehicle to demonstrate standing: the statute allows the [State] to prove injury to a single resource.” (Quotation and brackets omitted.) Finally, the trial court reasoned that “general policy considerations support allowing the [State] to establish injury and damages using statistical methods.” The court stated:

American manufacturers now mass produce goods for consumption by millions using new chemical compounds and processes, creating the potential for mass injury. As a result, modern adjudicatory tools must be adopted to allow the fair, efficient, effective and responsive resolution of claims of these injured masses. In a perfect setting, the [State] would have the resources to test each individual well over a long period of time and precisely determine its damages. However, if such a process were undertaken here, it would have to continue beyond all lives in being. The Court simply cannot support such a process.

*253Moreover, requiring the [State] to test each individual well undoubtedly and unfairly “tilts the scales” in [Exxon’s] favor .... Here, . . . the necessary additional litigation costs the [State] would have to bear would consume much of any recovery, making continued pursuit of the litigation fruitless. Because of these public policy interests, the Court finds that allowing the [State] to use statistical methods of proof is relevant to prove injury and damages in this case.

The fact is that for decades, judges, lawyers, jurors, and litigants have shown themselves competent to sift through statistical evidence in a variety of contexts, from mass toxic torts to single-car collisions. Not only have they shown themselves competent, but also such evidence has become a generally accepted method for a plaintiff to prove his case. This Court is simply not persuaded by [Exxon’s] attempt to frame this case as a class action. As a result, the Court rejects the notion that New Hampshire law forbids the use of a statistical approach to prove injury-in-fact.

(Quotations, citations, brackets, and ellipsis omitted.)

Exxon subsequently attempted to exclude the opinions of the same three experts on grounds of reliability, arguing that the State’s experts used improper methodologies and, even when they used proper methodologies, they applied the methodologies incorrectly to the facts and data provided. After conducting a thorough analysis of each of the statistical methods employed by the State’s experts, the trial court concluded that their opinions and methodologies were reliable and denied Exxon’s motion.

Following the trial court’s ruling that the statewide approach was acceptable, Exxon sought an interlocutory transfer to this court. The trial court denied the request, finding that Exxon failed to satisfy the requirements of New Hampshire Supreme Court Rule 8(1). See SUP. Ct. R. 8 (interlocutory appeal from ruling). In its order, the trial court noted that, despite its rulings otherwise, Exxon continued to assert that it is feasible to try this case on a well-by-well approach. As the court explained, under Exxon’s approach,

the State would identify a contaminated'drinking-water well and then trace the source of contamination to a particular physical location that leached gasoline into the ground. These locations will usually be businesses associated with gasoline, like retail gas stations and junkyards. From here, these entities can then trace the gasoline back through the product chain to the wholesaler and eventually the refiner. In this way, either the State or the retailers *254can spread the liability throughout the product chain. [Exxon] explain[s] that because all entities in a product chain would be liable for the State’s harm, the State should be required to proceed on a well-by-well approach.

The trial court found this method to be “technically and scientifically infeasible.” The court reasoned:

The State’s case attempts to impose liability on manufacturers and refiners. Without decision makers selecting, marketing, and reformulating MTBE, it would never have been included in the RFG program and would never have been imported into New Hampshire to spill, leak, and evaporate. Gasoline imported into New Hampshire would not have been capable of contaminating the State’s water resources in the vast, seemingly uncontainable way it has if it did not contain MTBE. The State has chosen to pursue the named Defendants because they created the initial risk that led to widespread contamination. Based on this selected class of defendants, product tracing is virtually impossible.

Defendants themselves admit that tracing MTBE found in a contaminated well all the way back to the refiner is virtually impossible because MTBE lacks a chemical signature, linking it to a particular refiner. Additionally, a contaminated well, many times, cannot be traced to a particular retailer, making it practically impossible to trace MTBE to a specific wholesaler.

Following the jury verdict, Exxon argued in its motion to set aside the verdict that the statewide approach allowed the State “to prove its private well and ‘future injury’ case using statistical extrapolations from experts about potential hypothetical impacts rather than particularized evidence of an actual injury” and that this “resulted in the State being able to avoid its burden to prove individualized causation with respect to particular private well impacts.” The trial court denied the motion, stating that its prior rulings on this issue were rulings of law and that because “Exxon does not raise any new facts regarding these rulings and it does not contend that the jury’s verdict was conclusively against the weight of the evidence,” the argument “did not properly fall within the purview” of a motion to set aside.

On appeal, Exxon argues that the trial court erred in allowing the State to prove its case on a statewide basis. Exxon asserts that “[e]very other court to address the issue has recognized that MTBE tort cases depend overwhelmingly on individualized questions of law and fact, and thus are not amenable to proof on a mass basis.” According to Exxon, the trial court “broke from these precedents” in allowing statewide aggregate evidence. The State argues that the “immense scope of Exxon’s pollution” has *255“directly affected a substantial portion of the State’s population” and that “[t]he statewide nature of Exxon’s tortious conduct, therefore, required adjudication on a statewide basis.” (Quotation omitted.) The State asserts that Exxon has “mischaracterize[d] both the trial record and the relevant standards of review.”

We review challenges to a trial court’s evidentiary rulings under our unsustainable exercise of discretion standard and reverse only if the rulings are clearly untenable or unreasonable to the prejudice of a party’s case. In the Matter of McArdle, 162 N.H. at 485.

Exxon cites In re Methyl Tertiary Butyl Ether Products Litigation, 209 F.R.D. 823 (S.D.N.Y. 2002), as an example of why “MTBE tort cases depend overwhelmingly on individualized questions of law and fact.” The trial court, however, found this and other MTBE cases involving a determination as to “injury in fact” to be unhelpful, as “the facts of this case are very different.” In contrast to the New York MTBE case in which the court dismissed full categories of class plaintiffs who had actually tested and detected no MTBE in their wells, the trial court noted that here, “the [State] has tested many wells where it has discovered the existence of MTBE. It merely seeks to extrapolate that information in order to establish further injury.” The trial court agreed that “if the [State] had not tested any wells or had tested wells and found no MTBE, the [State’s] pursuit of a statistical approach would be fruitless.” As further distinguishing the New York MTBE case, the trial court noted that, whereas in the New York case, the plaintiffs’ allegations neither contained any statistics pertaining to MTBE detection rates for private wells nor established that the private wells were located in proximity to possible release sites, here the State “provided the Court with adequate statistical evidence through their experts,” and, the State seeks recovery “on the basis of ‘high-risk’ areas only.”

At trial, the State offered proof based upon expert testimony regarding 1,584 specific sites where MTBE has been known to leak and has contaminated the subsurface. The State also introduced scientific evidence through expert testimony that 5,590 drinking water wells serving 16,276 people are contaminated with MTBE at levels over 13 ppb, and that many more are expected to become contaminated in the future. Dr. Fogg used substantial data on MTBE contamination in the state to calculate statistically the number of drinking wells currently contaminated by MTBE. The State’s experts expressly accounted for the fact that “every site is different.” Exxon does not contend on appeal that the expert evidence was irrelevant or unreliable.

Based upon the record, we conclude that the trial court’s determination that the use of statistical evidence and extrapolation to prove injury-in-fact *256was proper was not an unsustainable exercise of discretion. See Bodwell v. Brooks, 141 N.H. 508, 510-11 (1996) (statistical probability evidence may be used to rebut the presumption of legitimacy); Rancourt v. Town of Barnstead, 129 N.H. 45, 50-51 (1986) (validity of a town’s growth control ordinance rests upon a relationship between the town’s growth restrictions and a projection of “normal growth” based upon scientific and statistical evidence); In re Neurontin Marketing and Sales Practices, 712 F.3d 21, 42 (1st Cir. 2013) (“courts have long permitted parties to use statistical data to establish causal relationships”).

IX. RSA 507:7-e and DeBenedetto

Exxon argues that it was “unfairly prejudiced in its ability to present its defense” under RSA 507:7-e (2010) and DeBenedetto v. CLD Consulting Engineers, Inc., 153 N.H. 793 (2006). Before trial, Exxon filed disclosures containing lists of several thousand non-litigants, including the names of gasoline suppliers, gasoline importers, foreign refiners, domestic refiners, distributors, trucking companies, and persons with leaking underground storage tanks. After reviewing these initial disclosures, the trial court found that they did not sufficiently allege fault against the non-litigants and, as a result, did not provide either the court or the State with adequate notice under DeBenedetto. The trial court ordered Exxon to “set forth, with specificity, a good faith basis for why each party listed within their disclosures is responsible for the claims made by the State.”

The State subsequently moved to strike Exxon’s supplemental disclosures, maintaining that Exxon failed to comply with the trial court’s order because the disclosures did not provide sufficient evidence specific to each DeBenedetto party. In its order, the trial court stated:

Despite the fact that the New Hampshire Supreme Court has never directly addressed the present DeBenedetto issues, it has, nonetheless, supplied a framework to guide this court’s analysis. This framework is made up of four principles: first, that RSA 507:7-e applies to all parties contributing to the occurrence giving rise to the action, including those immune from liability or otherwise not before the court; second, that a civil defendant who seeks to deflect fault by apportionment to non-litigants is raising something in the nature of an affirmative defense; third, the defendant carries the burdens of production and persuasion; and fourth, that a defendant may not easily shift fault under RSA 507:7-e; allegations of a non-litigant tortfeasor’s fault must be supported by adequate evidence before a jury or court may consider it for fault apportionment purposes.

*257(Quotations and citations omitted.)

The trial court found “the most notable portion of the framework, and the most helpful in the present analysis, is that portion identifying non-litigant liability as akin to an ‘affirmative defense.’ ” Because in New Hampshire defendants are required to plead affirmative defenses to provide the plaintiff with adequate notice of the defense and a fair opportunity to rebut it, the trial court determined that “when a defendant raises a defense under DeBenedetto, its disclosure must provide the plaintiff with adequate notice of the defense and the plaintiff must be given fair opportunity to rebut it.” Looking at the requirements of other jurisdictions, the court reasoned that the Colorado standard “for evaluating a defendant’s notice of non-litigant fault [is] persuasive in molding a standard for ‘adequate notice’ under DeBenedetto.” Thus, the court concluded that

proper notice in the DeBenedetto context requires [Exxon] to provide to the State identifying information for the nonparty in addition to a brief statement of the basis for believing such nonparty to be at fault. Furthermore, the notice must allege sufficient facts to satisfy all the elements of at least one of the State’s claims.

(Quotations, citations, and brackets omitted.) The trial court rejected Exxon’s assertion that it need demonstrate only “how a DeBenedetto party contributed to the harm alleged by the State, not correspond each DeBenedetto party to individual claims,” reasoning that Exxon cannot assert that it has “any less of a burden than to link [its] own allegations of non-litigant fault to at least one of the claims asserted by the State.” (Quotation omitted.)

Thereafter, the trial court determined that with respect to negligence, Exxon “must assert that a nonparty owed a duty with respect to MTBE gasoline and breached that duty. This will require demonstrating that a nonparty had some knowledge of MTBE or its characteristics, or should have had some knowledge.” With respect to products liability, the trial court determined that Exxon “must assert that a nonparty knew or reasonably should have known of the nature of MTBE upon which the State’s claims are based in order to show that an entity below [Exxon] in the product chain is similarly culpable and/or owed a similar duty to warn.” The trial court explained that Exxon “need not show that a nonparty was aware of the unique nature of MTBE ... However, a nonparty cannot possibly [have] foreseen the type of harm alleged by the State absent some knowledge that MTBE was generally present in gasoline or could have been present. Alternatively, [Exxon] may demonstrate that a nonparty should have known of MTBE.”

*258After the jury verdict, Exxon moved to set aside the verdict and for a new trial. Exxon argued that the trial court erred by: (1) “improperly requiring ExxonMobil to prove that the non-parties were liable for the State’s claims, rather than proving only that they contributed to the State’s injury”; (2) “preventing ExxonMobil from relying on RSA 146-A to establish the non-parties’ fault”; (3) “requiring proof that the non-parties had actual or constructive knowledge of MTBE’s presence in gasoline before contributing to the State’s injury”; and (4) requiring it to present “categories of evidence rather than evidence about the actions of particular individuals in connection with particular injuries.”

The trial court rejected Exxon’s first three challenges because they raised pure questions of law that the court addressed pretrial and “Exxon has raised no new fact or law to convince the Court to readdress these arguments.” Regarding the statewide proof claim, the trial court agreed with the State that allowing categories was a convenience, not a requirement, and “Exxon could have presented evidence regarding every individual DeBenedetto party, as opposed to categorical evidence.” As to the categories, the trial court found that “Exxon presented very little evidence establishing nonparty liability” and that its primary witness who testified regarding the various categories of nonparties “did not indicate that nonparties were aware of MTBE’s presence in gasoline during the relevant time period, and he never stated that nonparties were aware their actions caused spills and leaks that caused MTBE contamination.” Accordingly, the trial court concluded that it “cannot say that a jury verdict rejecting Exxon’s DeBenedetto defense was conclusively against the weight of the evidence.”

On appeal, Exxon argues that the trial court’s DeBenedetto rulings “deviate from clear precedent and denied Exxon a meaningful opportunity to prove that third parties contributed to at least part of the alleged harm.” Exxon asserts that the trial court’s ruling that Exxon had to link each DeBenedetto party to a claim made by the State “eviscerated Exxon’s statutory right to allocate fault to third parties.” The State argues that Exxon’s DeBenedetto argument is “unavailing because Exxon did not show at trial that non-parties were at fault for MTBE pollution.”

We review challenges to a trial court’s evidentiary rulings under our unsustainable exercise of discretion standard and reverse only if the rulings are clearly untenable or unreasonable to the prejudice of a party’s case. In the Matter of McArdle, 162 N.H. at 485. We review questions of law de novo. Sanderson, 146 N.H. at 600.

*259Pursuant to RSA 507:7-e and DeBenedetto, defendants may ask a jury to shift or apportion fault from themselves to other nonparties in a case. RSA 507:7-e, I, provides:

I. In all actions, the court shall:

(a) Instruct the jury to determine... the amount of damages to be awarded to each claimant and against each defendant in accordance with the proportionate fault of each of the parties; and

(b) Enter judgment against each party liable on the basis of the rules of joint and several liability, except that if any party shall be less than 50 percent at fault, then that party’s liability shall be several and not joint and he shall be liable only for the damages attributable to him.

“[F]or apportionment purposes under RSA 507:7-e, the word ‘party’ refers not only to ‘parties to an action, including settling parties,’ but to all parties contributing to the occurrence giving rise to an action, including those immune from liability or otherwise not before the court.” DeBenedetto, 153 N.H. at 804 (quotation, ellipsis, and citation omitted). “[A] defendant may not easily shift fault under RSA 507:7-e; allegations of a non-litigant tortfeasor’s fault must be supported by adequate evidence before a jury or court may consider it for fault apportionment purposes.” Id. “[A] civil defendant who seeks to deflect fault by apportionment to non-litigants is raising something in the nature of an affirmative defense’’ Goudreault v. Kleeman, 158 N.H. 236, 256 (2009). Accordingly, “the defendant carries the burdens of production and persuasion.” Id. Furthermore, “a defendant who raises a non-litigant apportionment defense essentially becomes another plaintiff who must seek to impose liability on a non-litigant just as a plaintiff seeks to impose it on him.” Id. (quotation and brackets omitted); see Wyle v. Lees, 162 N.H. 406, 413 (2011) (trial court implicitly concluded that the defendants failed to prove their allegations of comparative negligence for purposes of apportionment of damages).

As the trial court correctly concluded, apportionment under RSA 507:7-e requires proof of fault. DeBenedetto, 153 N.H. at 800 (apportionment must include all tortfeasors who are causally negligent by either causing or contributing to the occurrence in question). At trial, Exxon’s expert witness, Jeffrey A. Klaiber, an environmental consultant, testified for several days, including providing extensive testimony regarding typical spill and leak scenarios for the various categories of alleged faulty nonparties. He acknowledged, however, that he did not interview anyone at any of the sites that Exxon contends are responsible for MTBE contamination, that he did not know whether anyone who owned or operated any of *260those sites knew that MTBE gasoline behaves differently from other gasolines when released into the environment, and that he did not know if any of the owners or operators of those sites even knew that MTBE was in the gasoline that they were receiving. Nonetheless, the trial court allowed the jury to consider apportioning liability to those nonparties. The trial court instructed the jury:

In this state, courts and juries may apportion fault to all persons or entities who contributed to causing an injury, even if they are not parties to the lawsuit. What that means in this case is that if you find that the State has proven any of its three claims against ExxonMobil, then ExxonMobil shall have the burden of proving that some or all of its fault should be allocated to the nonparties identified in Defense Exhibit 1047.

The jury answered “No” to each portion of this question on the special verdict form: “Has ExxonMobil proven, by a preponderance of the evidence, that some or all of its fault should be allocated to nonparties in the following categories? ... a. Tanks With Holes . . . b. Aboveground Releases . . . c. Tanks With Releases . . . d. Junkyards.” Based upon the record, we are not persuaded by Exxon’s argument that it was denied “a meaningful opportunity” to apportion fault to third parties or that it suffered any prejudice from the trial court’s rulings. Accordingly, we find no error.

X. Parens Patriae

Exxon argues that the trial court erroneously decided that the State had parens patriae standing, rather than submitting this question to the jury. Exxon asserts that whether there is an injury to a “substantial segment” of the population is a question of fact for the jury, not a question of law for the judge, and that a rational jury could have found the State’s proof insufficient. The State argues that Exxon waived this argument because Exxon failed to raise it before the trial court, including failing to raise it in its motion for summary judgment on parens patriae issues or in its motion for a directed verdict, and failed to argue it in either its motion for JNOV or motion to set aside the verdict.

We have reviewed the record and agree with the State that Exxon has failed to demonstrate that it specifically raised this argument before the trial court. See Dukette, 166 N.H. at 255. Accordingly, because the argument is not preserved for our review, we decline to address it substantively. See N. Country Envtl. Servs., 150 N.H. at 619.

*261 XI. Future Well Impacts

Exxon argues that the State’s “future, speculative, and unknown well and site impacts” are not ripe for review. Before trial, Exxon raised this argument in a summary judgment motion. The trial court denied the motion, stating:

It is well settled in New Hampshire that an injured party may seek recovery for future harm that will arise from a current injury. In order to recover for future damages, a party need only show that there is evidence from which it can be found to be more probable than not that the future damages will occur. Thus, contrary to [Exxon’s] argument, New Hampshire has no absolute prohibition on awarding future damages.

The court finds that the State’s damages for future and unknown well impacts are fit for . . . judicial determination. Importantly, the injury causing the future harm has already occurred. The injury occurred when MTBE entered State waters. The State’s claim for future damages merely seeks to measure the extent of the harm caused, which New Hampshire allows. Furthermore, the court has already determined that the methods undertaken by the State’s experts for determining the future harm . . . are relevant and reliable. Therefore, the State’s future damages claims are ripe for review under the first prong of the ripeness test.

(Quotation, citations, and brackets omitted.)

Exxon moved for a directed verdict following the State’s conclusion of its case-in-chief arguing, in part, that the State failed to present its damages figure with sufficient certainty. Exxon argued that the State failed to prove that it has “sustained a cognizable injury” and that the State’s damages evidence was insufficient. The trial court rejected the motion, stating:

The State need only show an approximation of its harm. As this Court’s prior orders on this issue explain, the State does not need to have identified every contaminated well in New Hampshire to show it is injured. Nonetheless, the State presented testimony in its case-in-chief through Gary Beckett, Dr. Ian Hutchison, Dr. Graham Fogg, Steve Guercia, and Brandon Kernen. These witnesses estimated the number of wells that are currently suffering contamination based on statistical sampling, the location of spill sites, and the number and proximity of drinking wells in New Hampshire. The mere fact that the State’s damages figure is *262based on an approximation does not make it speculative or legally insufficient. Further, the evidence presented during the State’s case-in-chief regarding the estimated costs of remediation efforts based on estimated contamination is sufficient for a reasonable juror to conclude the State has suffered a cognizable injury.

(Citation omitted.)

Following the jury verdict Exxon moved for JNOV, arguing that “several aspects of the jury’s damages award for future well testing and treatment . .. are unsupported by the evidence.” Denying the motion, the trial court stated:

Exxon explains that even if it is liable, the damages figure the jury awarded is speculative because it is based on expert estimations and not supported by evidence; it is not sufficiently definite. The Court considered and rejected this argument in its directed verdict order: “The mere fact that the State’s damages figure is based on an approximation does not make it speculative or legally insufficient.” Because Exxon raises no new facts or law, the Court will not reconsider its prior ruling. As such, the record is not so clearly in Exxon’s favor that the Court can find the jury’s verdict is unsustainable.

(Citation omitted.)

In addition, Exxon moved to set aside the verdict and for a new trial, arguing that “[j]ust because MTBE is in groundwater now does not mean that it will injure private wells in the future,” and, therefore, “these projected injuries are speculative and were not ripe.” The trial court rejected Exxon’s argument, stating:

This Court has ruled that the State’s injury already occurred; MTBE has already been brought into New Hampshire. Exxon sought a jury instruction on imminent and immediate harm, which the Court denied. Whether the State has been injured is a question for the jury, but prospective damages are proper where there was evidence from which the jury could find it more probable than otherwise that such damage would occur. Because Exxon’s motion raises no new issues of law or fact, the Court declines to reconsider its prior rulings.

(Quotation and citations omitted.)

On appeal, Exxon argues that the trial court erred “in allowing the State to claim more than $300 million in damages for the costs of testing private *263wells for possible MTBE contamination, $150 million to treat whatever contamination is found in the wells in the future, and another $218 million for anticipated generalized costs to characterize . . . and clean up release sites,” because these claims are unripe and should be dismissed. Exxon asserts that the State “did not present proof of actual or imminent contamination to particular private wells,” and that the State’s claims for treatment of future private-well impacts “are even more uncertain, remote, and contingent.” According to Exxon, the trial court’s ruling “dramatically increased the scope of this suit and took the [court] into territory where no common law court has gone before.”

The State argues that its harm “exists today, and recompense for this type of harm is certainly no less recoverable than future medical expenses or damages for loss of income, both of which are regularly awarded in tort actions without raising ripeness concerns.” The State also asserts that its testing and future-treatment claims are ripe because the State “presented concrete evidence of damage that already has occurred.”

“[R]ipeness relates to the degree to which the defined issues in a case are based on actual facts and are capable of being adjudicated on an adequately developed record.” Appeal of City of Concord, 161 N.H. 344, 354 (2011). Although we have not adopted a formal test for ripeness, we have found “persuasive the two-pronged analysis used by other jurisdictions that evaluates the fitness of the issue for judicial determination and the hardship to the parties if the court declines to consider the issue.” Appeal of State Employees’ Assoc., 142 N.H. 874, 878 (1998).

We find no error in the trial court’s rulings on this issue. The State’s claims for future testing and treatment are fit for judicial determination as the harm from MTBE has already occurred. Cf. In re Methyl Tertiary Butyl Ether (“MTBE”) Prod., 175 F. Supp. 2d 593, 607-11 (S.D.N.Y. 2001) (individual plaintiffs could not show a present threat of imminent harm because either they had not tested their private wells or tests did not detect MTBE in their wells). The record establishes that, as of the time of trial, over 1,000 drinking wells in the state had tested positive for MTBE, and, of those, 358 wells were contaminated at levels over the maximum contaminant level of 13 ppb. The record also establishes that more than 5,000 wells, which have not yet been tested, were likely already contaminated with MTBE above 13 ppb at the time of trial. The record also contains evidence that the damage from MTBE contamination is not limited to drinking wells. According to the State’s experts, MTBE has a “residence time” of up to 50 years, during which time it gradually seeps through subsurface zones toward wells, lakes, and wetlands. The State’s experts testified that, *264although leaks from some underground storage tanks might not yet have been detected, those leaks “will continue to pose a hazard to groundwater quality.” As the jury was instructed:

The State is entitled to be fully compensated for the harm resulting from ExxonMobil’s legal fault.

In determining the amount of damages to allow the State, you may.... consider whether it is more probable than otherwise that its damages will continue into the future as a direct, natural and probable consequence of ExxonMobil’s legal fault and, if so, award it full, fair, and adequate compensation for those future damages.

Exxon does not present any argument on the hardship prong of the ripeness test, and we therefore consider any argument regarding that prong to be waived. See State v. Roy, 167 N.H. 276, 286 (2015).

XII. Prejudgment Interest

Exxon argues that the trial court should not have awarded prejudgment interest on future costs. Following the jury verdict, the State moved for taxation of costs, including prejudgment interest pursuant to RSA 524:l-b (2007). Exxon moved to preclude the addition of prejudgment interest on the future costs portion of the State’s damage award, arguing that such an award would not serve the statute’s purpose and “would amount to an illegal punitive award.” Exxon asserted that because money has time value, interest is added to damages for past harms to take into account the time during which the plaintiff was deprived of its use, but “[t]hat rationale is inapposite to an award for future costs associated with establishing investigation, testing and treatment programs and with MTBE impacts that have not yet occurred.” The State objected, arguing that because the injury has already occurred when MTBE entered New Hampshire’s waters, Exxon’s “motion fails in its basic premise; there are no future injuries here.” The State also argued that even assuming future injuries were at issue, the statute “does not distinguish between past and future costs or harm.”

The trial court rejected Exxon’s arguments, noting that, although during trial, “the State categorized its damages as past, current, and future for purposes of breaking the figure into parts for evidentiary presentation,... this presentation was not intended to and did not define the State’s injury.” The court reasoned:

The State presented substantial evidence that the damage to its waters had already been done, MTBE had already been imported *265into the State, and this is the presentation of evidence that the jury accepted by its verdict. The mere fact that the State characterized part of its damages figure as that for future testing and remediation does not mean that it did not suffer the loss of use of these monies prior to the jury’s verdict in this case. Further, had these monies been available during the last decade when litigation was pending, arguably, the cost to test and remediate would be lesser now.

On appeal, Exxon argues that the trial court erred “by awarding prejudgment interest on the total judgment amount, or $236,872,664, when $195,243,134 of those damages . . . were for the State’s claims for investigating, testing, characterizing, and treating alleged MTBE contamination in New Hampshire’s private wells and future costs for site investigation and remediation.” According to Exxon, “[p]rejudgment interest on those future costs fails to serve the compensatory purpose of RSA 524:1-b and thus should not have been awarded.” The State argues that Exxon “makes no effort to square its argument with [the statute’s] text,” and that “RSA 524:l-b has dual purposes: to accelerate settlement and provide compensation for the loss of use of money damages.” (Quotation and emphasis omitted.) The State asserts that “[ajwarding prejudgment interest to all of the State’s damages satisfies the objective of accelerating settlement, regardless of when the money underlying the damages is spent,” and that “because the contamination occurred in the past, ongoing treatment and testing does not, as Exxon claims, represent ‘future harms’ or damages the State has yet to incur.” (Quotation, brackets, and citation omitted.)

“Ordinarily, upon a verdict for damages and upon motion of a party, interest is to be awarded as part of all judgments.” State v. Peter Salvucci Inc., 111 N.H. 259, 262 (1971). Pursuant to RSA 524:1-b, in all civil proceedings, other than an action on a debt,

in which a verdict is rendered or a finding is made for pecuniary damages to any party, whether for personal injuries, for wrongful death, for consequential damages, for damage to property, business or reputation, for any other type of loss for which damages are recognized, there shall be added... to the amount of damages interest thereon from the date of the writ or the filing of the petition to the date of judgment.

RSA 524:l-b; see RSA 524:l-a (2007).

The interpretation of a statute is a question of law, which we review de novo. In the Matter of Liquidation of Home Ins. Co., 166 N.H. 84, 88 *266(2014). We are the final arbiters of the legislature’s intent as expressed in the words of the statute considered as a whole. Id. We first examine the language of the statute, and, where possible, ascribe the plain and ordinary-meanings to the words used. Id. Our goal is to apply statutes in light of the legislature’s intent in enacting them, and in light of the policy sought to be advanced by the entire statutory scheme. Id.

The purpose of the legislature in enacting RSA 524:l-b was “to clarify and simplify the existing law and to make plain that in all cases where the trial court awarded money to the party entitled to be compensated, interest at the legal rate is to be added to the award.” Id. at 89 (quotation omitted). Even assuming, without deciding, that the damages award included some amount for “future” costs, the plain language of the statute does not distinguish between past and future damages. Rather, the statute mandates the award of prejudgment interest “to the amount of damages.” Thus, the plain language of the statute provides no support for Exxon’s argument differentiating past and future damages for purposes of calculating and awarding prejudgment interest. See Starr v. Governor, 151 N.H. 608, 610 (2004) (we will not add words to a statute that the legislature did not see fit to include). Accordingly, we hold that the trial court did not err in awarding prejudgment interest as to all of the State’s damages.

XIII. State’s Cross-Appeal

The State cross-appeals from the trial court’s order imposing a trust upon approximately $195 million of the damages award. Before trial, Exxon moved “to establish a court supervised trust fund for any monies the State recovers in this litigation” and for “an accounting for all settlement proceeds the State has received to date.” Exxon argued that the need for a trust fund was necessary “given the speculative nature of the State’s future damages,” and that a “ ‘pay-as-you-go’ fund .. . would effectively limit the State’s recovery to those future testing, monitoring, treatment, and remediation costs the State actually incurs.” The State objected, and the trial court deferred ruling until after trial.

Following the verdict, Exxon renewed its motion, asserting that “[t]he need for a court-supervised trust is proven by the recent press coverage indicating that the New Hampshire Legislature intends to divert funds awarded in this litigation away from MTBE remediation,” and that, in two recent Maryland cases, the court had required court-supervised trust funds in medical monitoring cases involving alleged MTBE exposures. The State objected, arguing, among other contentions, that, because the trial court had already determined that “the underlying causes of action do not require the State to prove how it will spend damages, there is no basis for *267imposing a court-supervised trust requiring the State to establish how the money will be spent as a prerequisite to obtaining the damages for which Exxon was found liable.” In addition, the State argued that Exxon “has not cited a single case, statute, or other authority that would allow [the trial court] to establish a trust fund for monies received by the State pursuant to a jury award in a products liability case,” and that Exxon’s reliance upon the Maryland cases was misplaced.

The trial court granted Exxon’s motion in part, agreeing that “a trust is necessary to protect the res of the jury damage award.” The trial court reasoned that “because the State brought this case in its parens patriae/ trustee capacity,” the “State’s obligation to remediate contaminated water exists independent of Exxon’s interest in the damages figure the jury awarded the State,” and the State “must ensure it has adequate resources to test and treat New Hampshire’s waters in the future.” The court declined to impose a trust upon the amount of damages designated for past cleanup costs, reasoning that “those monies must be available upon final judgment” for the State to reimburse itself. However, the court imposed a trust upon the amount of damages designated for 228 high-risk sites, sampling private drinking water wells, and treating drinking water wells contaminated with MTBE at or above the maximum contaminant level. The court rejected Exxon’s request for an order compelling the State to disclose how it would proceed with testing and remediation, but noted that “to the extent Exxon has a legal interest in a trust as a beneficiary at the termination of the trust, it may file a proposed procedure for how the trust should function.” The trial court deferred deciding whether the trust would be court-supervised, and a hearing date was set for the court “to consider each party’s proposal for the administrative details of a trust.”

Before the scheduled hearing date, the State moved for reconsideration of the trial court’s order, Exxon filed this appeal, and the State filed its cross-appeal. We subsequently issued an order staying the appellate proceedings to allow the trial court to issue a final decision on the State’s motion for reconsideration. The trial court thereafter denied the motion. The court noted at the outset that “it would be inefficient for the Court to decide all the relevant details of a trust now, if the Supreme Court is being asked to decide whether the existence of a trust is permissible. As such, this Court interprets the Supreme Court order to require a ruling on imposition of a trust but not the details.” The trial court rejected the State’s arguments that, among other things, the court conflated parens patriae and the public trust doctrine, failed to comply with RSA 6:11, III (Supp. 2014), and violated separation of powers. The trial court also rejected the State’s argument that Exxon lacked standing, stating that “the Court specifically *268left open the question of whether Exxon has standing” and that “Exxon’s standing was irrelevant to the Court’s determination to impose the trust.”

On appeal, the State argues that the trial court’s imposition of a trust was erroneous for several reasons, including that no common law precedent or statute provides for the imposition of a trust over the State’s damages award. Exxon argues that trial courts have “broad and flexible equitable powers,” which include the power to establish a trust over the damages awarded in this case. (Quotation omitted.)

Although we recognize that “[t]he propriety of affording equitable relief in a particular case rests in the sound discretion of the trial court,” Libertarian Party of N.H. v. Sec’y of State, 158 N.H. 194, 196 (2008), this principle does not apply to the remedy in this case. The common law remedy for a tort law cause of action is lump-sum damages. See Reilly v. United States, 863 F.2d 149, 169 (1st Cir.1988) (under the common law rule, “a court’s authority to award damages for personal injuries is limited to making lump-sum judgments”); see also In re Methyl Tertiary Butyl Ether (“MTBE”), 56 F. Supp. 3d 272, 273, 275 (S.D.N.Y. 2014) (declining to impose a reversionary trust on damages awarded for Exxon’s liability on claims of public nuisance, negligence, trespass, and products liability for failure to warn, because the remedy for a traditional tort law cause of action is lump-sum damages). Thus, in the absence of a statute or an agreement between the parties, when a tortfeasor loses at trial it must pay the judgment in one lump sum. See Reilly, 863 F.2d at 170; see also Vanhoy v. United States, 514 F.3d 447, 454-55 (5th Cir.2008) (court refused to deviate from a conventional lump-sum award and create a reversionary trust over damages in the absence of any applicable statutory or precedential requirement); Frankel v. Heym, 466 F.2d 1226, 1228-29 (3d Cir. 1972) (“courts of law had no power at common law to enter judgments in terms other than a simple award of money damages”; thus, “court should not make other than lump-sum money judgments” in case brought under Federal Tort Claims Act “unless and until Congress shall authorize a different type of award”).

The trial court reasoned that a trust was required because the State brought this action in its parens patriae capacity. Parens patriae, however, is simply a standing doctrine. See Hess, 161 N.H. at 431-32. As we explained in Hess, “[t]he public trust doctrine, from which the State’s authority as trustee stems, and the parens patriae doctrine are both available to states seeking to remedy environmental harm.” Id. at 431. ‘While the public trust doctrine is its own cause of action, parens patriae is a concept of standing, which allows the state to protect certain quasi-sovereign interests.” Id. at 431-32 (quotations omitted). “Parens patriae *269does not provide a cause of action, but may provide a state with standing to bring suit to protect a broader range of natural resources than the public trust doctrine because it does not require state ownership of such resources.” Id. at 432. Accordingly, we are not persuaded that the fact that the State was allowed to proceed under parens patriae standing authorizes the imposition of a trust over the money damages awarded for Exxon’s torts. In the absence of statutory or precedential support, we decline to deviate from the conventional lump-sum damages award and, accordingly, reverse the trial court’s imposition of a trust as erroneous as a matter of law.

Affirmed in part; and reversed in part.

Hicks, J., and VAUGHAN, J., retired superior court justice, specially assigned under RSA 490:3, concurred.