On September 6, 2022, the U.S EPA’s long-awaited proposed rule to list perfluorooctanoic acid (PFOA) and perluoroocanesulfonic acid (PFOS) as CERCLA hazardous substances was published in the Federal Register (Proposed Rule).[1] This triggers a 60-day public notice and comment period. As the first compounds ever proposed for hazardous substance listing under Section 102(a) of CERCLA, …