D.C. Circuit Upholds EPA’s Hazardous Substance Rule for PFOA, PFOS
On August 18, 2026, the D.C. Circuit upheld EPA’s hazardous substance rule for PFOA and PFOS under CERCLA.
Why it matters: Environmental and corporate lawyers must prepare for increased CERCLA liability and enforcement related to persistent PFAS chemicals.
- On August 18, 2026, a three-judge panel unanimously upheld EPA's 2024 rule designating PFOA and PFOS as hazardous substances under CERCLA.
- The court confirmed CERCLA’s standard requires a scientifically supported possibility of harm, not certainty, validating EPA's approach.
- EPA can now enforce cleanup and cost recovery against polluters releasing these persistent and harmful chemicals.
- The ruling heightens legal risks tied to PFAS contamination for companies and reinforces proactive compliance importance.
On August 18, 2026, the U.S. Court of Appeals for the D.C. Circuit upheld the Environmental Protection Agency (EPA) final rule from May 2024, designating perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). This ruling solidifies EPA's regulatory authority over these persistent toxic chemicals.
The court rejected challenges to EPA’s regulatory impact analysis, ruling that the agency reasonably estimated cleanup costs and adequately addressed CERCLA’s multi-step enforcement framework. Importantly, the decision clarifies that CERCLA's “may present substantial danger” standard requires only a scientifically supported possibility of serious harm, rather than absolute certainty of harm. As highlighted by legal analysis from Holland & Knight, this affirms EPA’s discretion in managing emerging environmental risks despite uncertainties.
EPA’s designation allows the agency to pursue cleanup cost recovery and take enforcement actions against parties responsible for PFOA and PFOS releases. These chemicals belong to the broader group of per- and polyfluoroalkyl substances (PFAS), notorious for their environmental persistence and health concerns, prompting heightened regulatory focus.
For environmental attorneys and corporate counsel, the ruling signals increased CERCLA liability exposure and enforcement risk tied to PFAS contamination. Companies handling or producing these substances should prioritize compliance strategies to mitigate potential legal and financial consequences, as emphasized by commentary from Bergeson & Campbell.
This decision enhances EPA's enforcement toolkit to address nationwide PFAS contamination effectively, reinforcing the legal landscape for contaminated site management and corporate accountability.
By the numbers:
- August 18, 2026 — Date D.C. Circuit issued unanimous ruling
- May 2024 — When EPA issued the final hazardous substance rule
- 3 judges — Panel reviewing the EPA’s PFOA and PFOS designation