On May 30, 2023, the comment period closed on EPA’s proposed maximum contaminant levels (“MCLs”) for six PFAS at which time EPA had received 97,793 comments. Under the proposed rule EPA would set MCLs for Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonic acid (PFOS), Perfluorononanoic acid (PFNA), Hexafluoropropylene oxide dimer acid and its ammonium salt (HFPO-DA a.k.a. GenX), Perfluorohexane sulfonic acid (PFHxS) and Perfluorobutane sulfonic acid (PFBS). As described in our earlier post, EPA proposed an MCL of 4 ppt for PFOA and PFOS and a Hazard Index approach for mixtures of PFHxS, HFPO-DA, PFNA, and PFBS. Comments on the proposed MCLs were submitted by a wide group of interested parties including water suppliers and associations, individuals, cities and towns, individual companies, industry associations, non-governmental organizations, and state environmental agencies. EPA has targeted early September 2024 for issuance of the final rule.