The D.C. Circuit has upheld EPA's 2024 designation of PFOA and PFOS as hazardous substances under the federal Superfund (CERCLA) law, rejecting industry challenges that EPA exceeded its statutory authority or failed to properly assess costs and benefits. The Aug. 18, 2026 ruling is significant because it confirms EPA's broad discretion to designate substances as hazardous when they meet CERCLA's statutory criteria and could pave the way for additional PFAS or other chemicals to receive similar designations. The decision also reinforces the potential for expanded cleanup and liability obligations for entities associated with PFAS contamination, while rejecting industry's proposed requirement that EPA demonstrate a separate, heightened level of "substantial danger" before making a designation.