D.C. Circuit Upholds CERCLA Designations for PFOA and PFOS

The D.C. Circuit rejected petitions brought by the U.S. Chamber of Commerce and other industry groups that asked the court to overturn the EPA’s designations of PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The petitioners argued that (1) the EPA’s interpretation of “hazardous substances” was contrary to law; (2) the EPA’s cost-benefit analysis provided insufficient notice to the parties; and (3) the EPA’s cost-benefit analysis and decision to regulate in the face of uncertainties was arbitrary and capricious. The D.C. Circuit rejected each of these challenges.

First, based on the “plain language” of the statute, the D.C. Circuit held that the phrase “may present substantial danger” in CERCLA’s definition of a “hazardous substance” does not mean that the EPA had to find that the danger will be actually existing or real. Second, the D.C. Circuit concluded that the EPA provided adequate notice of the cost-benefit analysis through its earlier economic assessment and related request for comments. Third, the D.C. Circuit concluded that the EPA acted reasonably “based on the record before it.”

August 18, 2026 | Chamber of Commerce of the United States of America v. Environmental Protection Agency, No. 24-1193 (D.C. Cir.).