Ethyl Corp. v. Environmental Protection Agency, 541 F.2d 1 (D.C. Cir. 1976) (en banc), cert. denied sub nom. E.I. du Pont de Nemours & Co. v. EPA, 426 U.S. 941 (1976)
Ethyl Corp. v.
Does the Clean Air Act authorize the EPA to restrict lead additives in gasoline upon a finding that emissions from those additives will endanger public health, even in the face of scientific uncertainty, and was the agency's rulemaking arbitrary or capricious under the APA?
Under Section 211(c)(1)(A) of the Clean Air Act, the EPA Administrator may control or prohibit any fuel or fuel additive if, in his judgment, any emission product of such fuel or additive will endanger the public health or welfare. Judicial review of such informal rulemaking proceeds under the APA's arbitrary-and-capricious standard, which requires that the agency examine the relevant data, consider significant comments and alternatives, and articulate a satisfactory explanation establishing a rational connection between the facts found and the choice made. The endangerment standard is preventive: the EPA need not wait for proof of actual harm but may regulate based on a reasonable assessment of significant risk and potential harm, especially when public health and vulnerable subpopulations are at stake.
The D.C. Circuit (en banc) upheld the EPA's lead-content regulations. The court held that Section 211(c) authorizes preventive regulation of fuel additives upon a reasonable endangerment finding; that the EPA reasonably concluded emissions from leaded gasoline would endanger public health; and that the rulemaking was not arbitrary or capricious.
Ethyl cements two enduring propositions. Substantively, it affirms that agencies charged with protecting public health may regulate proactively under an endangerment standard, relying on the best available science and reasonable inferences amid uncertainty. Procedurally, it is a leading articulation of "hard look" review: courts require reasoned decision-making but do not demand certainty or impose extra-statutory procedures. For law students, the case illuminates how statutory text ("in his judgment," "will endanger"), scientific evidence, and APA review interact in major health-protective rulemakings, foreshadowing later debates about risk, deference, and precaution in administrative law.