Fifth Circuit Vacates EPA Methylene Chloride Rule

The Fifth Circuit's September 15, 2026, decision vacated the Environmental Protection Agency's 2024 final rule prohibiting 40 of 53 identified uses of methylene chloride, a common industrial solvent, and invalidated the EPA's unreasonable‑risk determination under the Toxic Substances Control Act. In a unanimous opinion, the court held that the EPA must assess risk for each condition of use rather than as a whole, must factor in proven use of personal protective equipment (PPE), may not require zero risk, and may regulate only "to the extent necessary." The ruling is the first appellate interpretation of TSCA's "conditions of use" requirement and will shape how the EPA evaluates future chemicals, especially for regulated manufacturers, importers, and downstream users. Counsel should review existing TSCA compliance programs, document PPE practices, and anticipate more tailored, rather than blanket, restrictions. Companies that rely on methylene chloride in adhesives, paint removers, or automotive products should also watch for updated guidance or proposed rules that incorporate the court's holdings. The decision signals a stricter judicial oversight of agency risk assessments and may prompt additional challenges to EPA rulemaking across other hazardous substances.