947 F.2d 1201 (5th Cir. 1991)
Corrosion Proof Fittings v. EPA is a landmark administrative and environmental law decision that sharply defined what the Toxic Substances Control Act (TSCA) required of the Environmental Protection Agency when it sought to regulate a hazardous substance.
Did EPA comply with TSCA § 6 when it imposed a near-total ban on asbestos by adequately finding an unreasonable risk and selecting, with substantial evidence, the least burdensome regulation necessary to protect against that risk?
Under pre-2016 TSCA § 6(a), EPA may regulate a chemical substance upon finding it presents an unreasonable risk of injury to health or the environment. In promulgating a § 6 rule, EPA must impose the least burdensome requirement that will adequately protect against the unreasonable risk and must consider the factors enumerated in § 6(c)(1): (A) the health and environmental effects of the substance; (B) the magnitude of human and environmental exposure; (C) the benefits of the substance for various uses; (D) the reasonably ascertainable economic consequences of the rule (including effects on the economy, small business, and innovation); and (E) the availability and risks of substitutes. TSCA § 19(c)(1)(B) prescribes a substantial-evidence standard of review for § 6 rules, requiring the court to determine whether EPA's findings are supported by substantial evidence on the record as a whole. Read together, TSCA's text requires EPA to: (1) balance costs and benefits in determining whether a risk is "unreasonable"; (2) consider less burdensome regulatory alternatives (e.g., labeling, partial product-specific restrictions, or targeted controls) before selecting a ban; (3) assess the risks of substitutes and existing controls by other agencies; and (4) quantify and compare costs and benefits to the extent feasible, including appropriate treatment of time (e.g., discounting) and product-by-product analysis.
The Fifth Circuit vacated and remanded EPA's Asbestos Ban and Phase-Out Rule, concluding that EPA failed to demonstrate, with substantial evidence, that a near-total ban was the least burdensome regulation adequate to address any unreasonable risk posed by asbestos across the numerous product categories. Some unchallenged portions of the rule—such as prohibitions on new uses of asbestos and on certain paper products and flooring felt—remained in effect; the bans on most existing asbestos-containing products were set aside.
Corrosion Proof Fittings is a staple of administrative and environmental law courses because it demonstrates how statutory text can both authorize and limit agency power. It shows that when Congress directs an agency to adopt the "least burdensome" regulation and to consider enumerated factors, courts will require a robust, product-by-product, evidence-backed analysis that meaningfully balances costs and benefits and grapples with alternatives and substitute risks. The case also underscores the impact of statute-specific standards of review: TSCA's substantial-evidence bar demanded more than generalized assertions about danger; it demanded quantified, comparative reasoning. Doctrinally and practically, the decision raised the evidentiary and analytic hurdles for regulating under old TSCA § 6 and contributed to decades of limited action against dangerous chemicals. Its perceived rigidity was one of the central catalysts for Congress's 2016 TSCA amendments (the Lautenberg Act), which eliminated the "least burdensome" language and restructured how EPA assesses risk and considers costs—thereby partially superseding the decision's most restrictive implications. Still, Corrosion Proof Fittings remains a key authority on how courts read substantive constraints into environmental statutes and how agencies must justify sweeping rules.