Comment submitted by Michael Lengefeld

Lee Zeldin Administrator Environmental Protection Agency 1200 Pennsylvania Avenue NW Mail Code: 1101A Washington, DC, 20460 Re: Comments on EPA’s Rescission of Regulatory Determinations and Removal of Related Provisions for Four PFAS Substances (PFHxS, PFNA, HFPO-DA (GenX), and the mixture of these three PFAS plus PFBS) (Docket ID: EPA-HQ-OW-2025-0654-0010) Dear Administrator Zeldin, I write to oppose finalization of both the proposed PFAS Rescission Rule (and the proposed PFOA/PFOS Compliance Extension Rule). Together, these rules would strip enforceable drinking water protections for four “forever chemicals” and delay enforcement of the two that remain regulated, without any new scientific finding that the underlying health risks have changed. The rules also impose disproportionate, under-examined harms on Tribal communities, who face the greatest barriers to independently filling the gap EPA would leave behind. I. The Rescission Rule Rests on a Legally Vulnerable, Self-Contradicting Rationale As Harvard Law School's Environmental & Energy Law Program (EELP) documents in its June 23, 2026 legal analysis, EPA's Proposal to Remove Drinking Water Standards for Four PFAS Could Slow Future SDWA Rulemakings, EPA's sole legal basis for rescinding the standards for PFHxS, PFNA, HFPO-DA (GenX), and the Hazard Index mixture is a reversal of its own prior legal position — not new science: •EPA is contradicting its own 2024 reading of the same statute. In 2024, EPA read Safe Drinking Water Act §1412(b)(1)(E)'s “determination to regulate” to permit proposing drinking water standards concurrently with a preliminary determination, allowing one combined comment period. EPA's 2026 proposal now claims “determination to regulate” means only the final determination, requiring two sequential comment periods — and brands its own 2024 process “unlawful” on that basis. EPA offers no new textual, structural, or scientific argument for the reversal; it simply prefers a different reading. •EPA's 2024 rule already rebutted the argument it now makes. The 2024 rulemaking explained that a single comment period “provide[s] commenters with much more information” and stated “it is not clear what further benefit would be provided by two separate public comment periods.” EPA has not explained what changed. •EPA rescinded more than its own legal theory supports. EELP notes that EPA's 2026 statutory analysis, taken on its own terms, would at most show that the soonest EPA could propose the drinking water standards was alongside the final (not preliminary) determination to regulate — a defect that would call the standards into question, not the underlying determinations to regulate PFHxS, PFNA, HFPO-DA, and PFBS as hazardous. EPA rescinded both anyway, without considering the narrower fix. Under DHS v. Regents of the University of California (2020), an agency's failure to consider an obvious narrower alternative when unwinding a prior policy is a hallmark of arbitrary and capricious action. •The cost-benefit analysis covers only one of the four chemicals. EPA acknowledges it has “limited occurrence data” for PFNA, HFPO-DA, and PFBS, so its published estimates of $11.6 million/year in savings versus $6.7 million/year in foregone health benefits reflect only the effects of rescinding the PFHxS standard. EPA is asking the public to comment on — and proposes to finalize — rescission of standards for three additional chemicals whose costs and forgone health benefits it has not quantified at all. •No new health finding undercuts the 2024 record. EPA's 2024 rule found that PFHxS, PFNA, HFPO-DA, and PFBS exposure is linked to liver damage, low birth weights, and increased cancer risk, and projected that full implementation of the six-PFAS rule would prevent 29,858 illnesses and 9,614 deaths. None of that scientific record is revisited or rebutted in the 2026 proposal — only the legal procedure by which it was adopted. •EPA's own analysis warns the rule could backfire on EPA's stated goal. EELP concludes that if EPA's new two-step reading of §1412(b)(1)(E) is finalized and upheld, it will slow, not speed, future SDWA rulemakings for other contaminants by adding a second mandatory comment period and a second window for litigation. Thank you for your consideration. I value the work of the EPA in upholding and enforcing the SDWA. Sincerely, Mike Lengefeld, PhD