The U.S. Court of Appeals for the Fifth Circuit has vacated the EPA's risk management rule for methylene chloride and, more importantly, the unreasonable risk determination underneath it, in a ruling that rejects the agency's method for evaluating chemicals under the Toxic Substances Control Act. The court held the EPA lacks authority to judge a chemical as a whole rather than by its individual conditions of use, that the agency wrongly assumed workers ignore protective equipment, and that the statute's unreasonable risk standard is not a zero-risk mandate. The ruling in East Fork Enterprises v. EPA is being described by the lawyers who handle these cases as a complete teardown of the current risk evaluation process.
The rule that fell was substantial. The EPA finalized it in April 2024, prohibiting most uses of methylene chloride, 40 of 53 applications, in paint removers, adhesives, and sealants, and imposing a workplace chemical protection program with strict exposure limits on the remaining commercial uses. The chemical is genuinely dangerous: acute exposure can be fatal, and chronic exposure is linked to cancer and neurological and liver damage. The 2019 ban on consumer use in paint strippers remains in place, and public health groups warn that the vacated rule was protecting workers. The court's ruling did not dispute the dangers. It disputed the method.
The whole-chemical approach the court rejected
The court's central holding attacks the architecture of the EPA's risk evaluations. The agency determined that methylene chloride poses unreasonable risk as a whole, then worked down to conditions of use. The Fifth Circuit held that TSCA requires the opposite: the statute directs the agency to evaluate each condition of use, and the whole-chemical approach skips the analysis the statute demands. The distinction sounds technical, and it is the entire fight. If the agency must evaluate each use separately, the burden and the shape of every future risk evaluation changes, and the ones already completed were built on the rejected method.
The PPE holding is the part with the broadest practical reach. The EPA's evaluation assumed workers do not properly use personal protective equipment, on the theory that real-world noncompliance must be priced into the risk. The court held that assumption violates TSCA because PPE use is plainly a critical condition of use the agency must consider, and OSHA already requires it. The holding inverts a premise the agency has used across its chemical work: that a regulation should protect the worker who does not follow the rules, not just the one who does. That premise is now, in the Fifth Circuit, error.
The standard-of-review fight the statute lost
The court also settled the review standard, and the settlement favors challengers. Under Loper Bright, courts no longer defer to agency interpretations of ambiguous statutes, and the Fifth Circuit read TSCA's unreasonable risk standard accordingly: the statute does not authorize a precautionary or lowest-possible-risk principle, and the agency's reading was, in the court's words, far more conservative than the statutory term connotes. The scientific record got the same treatment. The court held the EPA's acute and chronic exposure limits were not supported by substantial evidence, criticizing reliance on a single human study of twelve individuals and a single rat study while contrary epidemiological evidence was discounted.
The consequences clause of the statute drew its own rebuke. TSCA requires the agency to regulate only to the extent necessary, weighing benefits, costs, and less restrictive alternatives. The court held the EPA failed that analysis and impermissibly shifted the burden to regulated entities to prove compliance. Read together, the holdings amount to a court telling an agency that its method, its standard, its science, and its alternatives analysis all failed at once. That is the teardown the commentary describes.
The ripple effects across the chemical docket
The ruling's reach is the reason it matters beyond methylene chloride. The same whole-chemical architecture underlies the EPA's pending rules and evaluations for chrysotile asbestos, trichloroethylene, perchloroethylene, and carbon tetrachloride, and the risk evaluation framework itself is being challenged in the D.C. Circuit. Every one of those proceedings now carries the Fifth Circuit's holding as ammunition, and the EPA may have to restart its methylene chloride evaluation from the conditions-of-use ground up. A single paint stripper case has become the template for attacking the entire program.
The reactions split exactly as the parties did. The American Chemistry Council praised the ruling. The Environmental Defense Fund called it wrong on the facts and wrong on the law. The EPA said it is reviewing the decision. Those positions are the predictable ones. The durable question is what the agency does next: it could petition for rehearing, it could restart the evaluation, or it could let the ruling stand and redesign its method around it. The first option keeps the fight alive. The third changes how every chemical in the country gets evaluated.