A US appeals court has upheld the Environmental Protection Agency’s (EPA) decision to classify two widely used PFAS chemicals as hazardous substances under the country’s Superfund programme.
The ruling preserves the EPA’s ability to pursue companies responsible for contamination involving perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).
The decision was issued on 18 August by a three-judge panel of the US Court of Appeals for the District of Columbia Circuit in Chamber of Commerce of the United States of America v. EPA, No. 24-1193.
The court rejected a challenge brought by seven industry groups, including the US Chamber of Commerce and organisations representing chemical and waste-management interests.
The result is a significant legal win for the EPA and means PFOA and PFOS remain subject to the liability framework established by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
Companies potentially responsible for releases could therefore face cleanup-related costs rather than those costs falling entirely on taxpayers.
What the hazardous substances ruling reinforces
The EPA introduced its designation in 2024 as part of efforts to address PFAS, a large family of synthetic chemicals used in products and industrial applications ranging from firefighting foams to non-stick cookware and stain-resistant materials.
Often described as “forever chemicals”, PFAS can persist for long periods in the environment. PFOA and PFOS have also been associated with a range of health concerns, increasing regulatory scrutiny of their manufacture, use and disposal.
Before the 2024 rule, PFOA and PFOS were treated under Superfund as pollutants or contaminants. The change to hazardous substances expanded the potential consequences for parties responsible for releases.
Court rejects industry cost arguments
The industry groups argued that the EPA had not adequately accounted for the potentially substantial financial consequences of the designation.
They also contended that the agency’s approach could encourage costly federal cleanups while shifting liability to private businesses.
The appeals court rejected those arguments, finding that the EPA acted within its legal authority and reasonably relied on the available scientific evidence.
The judges also concluded that imposing cleanup costs on responsible parties is consistent with one of the central objectives of CERCLA: making polluters contribute towards the costs of addressing contamination.
Wider implications for PFAS regulation
The ruling reinforces the EPA’s ability to use the Superfund framework when dealing with PFOA and PFOS contamination and could have important implications for companies that manufacture, handle, transport or dispose of materials containing the chemicals.
It also provides a clearer legal foundation for future enforcement and cleanup efforts as US regulators continue to confront the environmental persistence of PFAS.
The case marks an important development in the evolving regulatory landscape surrounding hazardous substances and could influence how businesses assess PFAS-related environmental liabilities in the years ahead.
