[Regulatory Update] US Appeals Court Upholds "Hazardous Substance" Designation of PFOA and PFOS — PFAS Enters an Era of Cleanup Liability and Corporate Costs

On 18 August 2026, the US Court of Appeals for the D.C. Circuit upheld the US Environmental Protection Agency's (EPA) 2024 rule designating PFOA and PFOS as "hazardous substances" under CERCLA (the Comprehensive Environmental Response, Compensation, and Liability Act, commonly known as the Superfund law). Industry groups including the US Chamber of Commerce had challenged the designation, but the court fully upheld EPA's scientific judgement and its authority to make the designation. The significance of the ruling lies not in introducing a new ban on PFAS use, but in settling the framework for corporate liability: who investigates and cleans up past PFAS contamination, and who bears the cost. The CERCLA designation triggers reporting obligations for releases above a certain quantity as well as cost-recovery and enforcement powers, but the designation itself does not automatically create cleanup obligations at every site; decisions are made case by case. EPA has also set out an enforcement discretion policy focusing on manufacturers that contributed significantly to contamination, while in principle excluding water utilities, farmers and others. For companies, PFAS management expands beyond identifying substances currently in use and switching to alternatives, to life-cycle risk management that also covers past use and disposal history, potential liability and future investigation and cleanup costs.