DC Circuit Upholds EPA's PFAS Hazardous Substance Designations under CERCLA: What In-House Counsel Need to Know

On August 18, 2026, the US Court of Appeals for the DC Circuit issued its decision in Chamber of Commerce of the United States of America v. EPA, No. 24-1193, denying all petitions to overturn EPA's 2024 designations of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) — two of the most common so-called "forever chemicals" — as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

Writing for the court, Judge Millett rejected challenges from seven major industry groups on statutory interpretation, procedural, and arbitrary-and-capricious grounds, finding that EPA acted within its authority, provided adequate notice-and-comment opportunities, and reasonably weighed costs and benefits.

Why This Matters for Companies

The decision cements the legal foundation for CERCLA's expanded reach over PFOA and PFOS, triggering immediate compliance obligations such as required release reporting.

More significantly, the designations open the door to EPA-compelled cleanups and cost-recovery enforcement actions against potentially responsible parties — including manufacturers, transporters, waste handlers, and current or former facility operators — under CERCLA's strict, joint-and-several liability framework.

Key Takeaways for In-House Counsel

Companies should immediately assess their PFAS exposure across operations, supply chains, and real estate portfolios. Those in manufacturing, waste management, construction, and recycling are particularly at risk, as the court acknowledged these industries historically used PFOA- and PFOS-containing products.

While the court noted CERCLA's multiple procedural safeguards and liability defenses — including "de minimis" contributor protections and innocent landowner defenses — in-house teams should not treat those as guarantees against liability.

Counsel should review existing environmental indemnities, insurance coverage, M&A representations, and disclosure obligations in light of this ruling, and prepare for potential contribution claims from co-located responsible parties at contaminated sites.