Comment submitted by Massachusetts Department of Environmental Protection

Summary: The Massachusetts Department of Environmental Protection (MassDEP) opposes the EPA's proposed rescission of regulatory determinations and standards for several PFAS substances (PFHxS, PFNA, HFPO-DA, and PFBS). They argue that the EPA lacks legal justification for the rescission, that the scientific basis for regulation remains strong, and that the Hazard Index approach should be retained to address cumulative risks.