On August 18, 2026, the U.S. Court of Appeals for the D.C. Circuit upheld the U.S. Environmental Protection Agency’s 2024 decision to list two PFAS chemicals — PFOA and PFOS — as hazardous substances under the federal Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or Superfund). As we previously reported, in January 2026 the D.C. Circuit held oral arguments in Chamber of Commerce of the United States of America v. EPA, No. 24-1193 (D.C. Cir.), in which various industry groups, including the U.S. Chamber of Commerce, challenged EPA’s final rule designating PFOA and PFOS as CERCLA hazardous substances. The industry groups argued that EPA’s designation was arbitrary and capricious and exceeded the Agency’s statutory authority under CERCLA, focusing in large part on EPA’s cost-benefit analysis and the rule’s anticipated financial impact. On appeal, the Court concluded that EPA acted within its authority to designate the chemicals as hazardous substances.

The hazardous substance designation for PFOA and PFOS fundamentally alters liability for the two substances. Substances designated as hazardous under CERCLA are subject to release reporting requirements, specific spill rules, release tracking requirements, and additional reporting mandates under other environmental statutes. In addition, the designation provides EPA with the authority to require potentially responsible parties, or PRPs, to abate and cleanup releases of PFOA or PFOS and for EPA, states, and private parties to pursue enforcement actions to recover cleanup costs from PRPs.

If the industry groups decide to appeal this decision, the case will head to the U.S. Supreme Court, which will then choose whether to review the case.