US EPA proposes rescinding SDWA/NPDWR determinations and related drinking-water standards for PFHxS, PFNA, HFPO‑DA (GenX) and Hazard Index mixtures (incl. PFBS)

EPA issued a proposed rule under the Safe Drinking Water Act to rescind the regulatory determinations and remove related regulatory provisions for PFHxS, PFNA, HFPO‑DA (GenX), and the Hazard Index mixture approach (including PFBS). If finalized, the proposal would remove the MCLGs/MCLs and associated monitoring/treatment/reporting requirements in 40 CFR Parts 141 and 142 that apply exclusively to those PFAS determinations, while leaving PFOA and PFOS MCLGs/MCLs unchanged. Compliance teams supporting drinking-water utilities and related supply chains should assess impacts to PFAS monitoring, treatment planning, primacy implementation activities, and customer communication, and consider participating in the comment process.