Comment submitted by Persistence Analytics Group LLC

Comment on EPA–HQ–OW–2025–0654 Rescission of Regulatory Determinations and Removal of Related Provisions for Four PFAS Substances The Environmental Protection Agency has identified an important procedural issue under the Safe Drinking Water Act. EPA states that the prior regulatory determinations and related provisions for PFHxS, PFNA, HFPO–DA / GenX chemicals, and the PFAS mixture hazard index were promulgated through an unlawful simultaneous process rather than the sequential procedure required by statute. That legal issue matters. But procedural correction should not create an implementation blind spot. EPA’s proposal would remove regulatory provisions that would otherwise have required monitoring, treatment, and reporting by public water systems for these contaminants. EPA also acknowledges that the action reduces previously expected benefits and may involve additional nonquantifiable foregone benefits. The key question is not only whether the prior rulemaking sequence was lawful. The key question is: What implementation controls will protect public health while EPA corrects the process? Persistence Analytics Group LLC / United Grid focuses on infrastructure assumption verification, public-cost exposure, and implementation integrity. From that perspective, EPA should not treat rescission as the end of the decision. It should treat rescission as a transition-risk event requiring a clear continuity plan. EPA should address: 1. Which public water systems were already preparing to monitor, treat, or report for the affected PFAS substances? 2. What data, monitoring, or occurrence information will be preserved during rescission? 3. How will EPA prevent procedural correction from becoming a loss of visibility into drinking-water risk? 4. What timeline will EPA use to revisit any lawful regulatory determinations through the proper SDWA sequence? 5. How will EPA communicate to states, tribes, utilities, water customers, and affected communities that rescission is based on procedure rather than a substantive finding that these contaminants are harmless? 6. What interim evidence standard will EPA use to track exposure, cost, treatment feasibility, and public-health implications while the regulatory process is corrected? EPA is correct to respect statutory sequencing. A legally defective process should not be defended merely because the policy goal is important. But the inverse is also true: A legal correction should not erase operational accountability. The public deserves to know whether rescission changes monitoring behavior, utility investment plans, state enforcement expectations, public-health visibility, treatment timelines, or community risk communication. EPA should therefore pair any final rescission with an implementation-continuity framework that preserves evidence, tracks exposure, clarifies next steps, and prevents regulated entities or affected communities from mistaking procedural rescission for a substantive safety determination. The operating rule should be simple: Trust the legal correction. Verify the public-health continuity. Do not release drinking-water protection against an unverified assumption. Respectfully submitted, Neil P. Osnato Founder Persistence Analytics Group LLC | United Grid National Security & Infrastructure Risk Analytics Demand Durability | Grid Stress | Load Integrity neil@persistenceanalyticsgroup.com 609-464-9055 https://persistenceanalyticsgroup.com/ SAM.gov Registered Vendor UEI: D3VYU39H6DX9 | CAGE: 19T34 D-U-N-S: 142849930