On March 14, 2023, the EPA proposed a National Primary Drinking Water Regulation under the Safe Drinking Water Act to establish Maximum Contaminant Levels (MCLs) for six per- and polyfluoroalkyl substances (PFAS):
- Perfluorooctanoic acid (PFOA)
- Perfluorooctane sulfonic acid (PFOS)
- Perfluorononanoic acid (PFNA)
- Hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX)
- Perfluorohexane sulfonic acid (PFHxS)
- Perfluorobutane sulfonic acid (PFBS).
The EPA anticipates finalizing the regulation by the end of 2023. Although the science around PFAS is still evolving, the EPA has touted the proposed rule as an essential measure that “will prevent thousands of deaths and reduce tens of thousands of serious PFAS-attributable illnesses.”