40 L. Ed. 2d 732, 94 S. Ct. 2140, 417 U.S. 156, 1974 U.S. LEXIS 60, 4 Envtl. L. Rep. (Envtl. Law Inst.) 20513, 18 Fed. R. Serv. 2d 877, 7 Empl. Prac. Dec. (CCH) 9374, 9 Fair Empl. Prac. Cas. (BNA) 1302