March 16, 2023
Bryan P. Franey, Esq. and Jessica D. Hunt, Esq.
MGKF Special Alert
Today, EPA proposed regulations to establish new maximum contaminant levels (MCLs) and new and revised maximum contaminant level goals (MCLGs) for six PFAS compounds: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), hexafluoropropylene oxide dimer acid (HFPO-DA) and its ammonium salts (commonly known as GenX chemicals), perfluorononanoic acid (PFNA), and perfluorobutane sulfonic acid (PFBS). An MCL is an enforceable standard, defined as the maximum level allowed of a contaminant or mixture of contaminants in water that is delivered to any use of a public water system. In contrast, an MCLG is a non-enforceable public health goal, defined as the maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on the health of persons would occur, allowing an adequate margin of safety.
The proposed MCLs and MCLGs are as follows:
|Compound||Proposed MCLG||Proposed MCL|
|PFOA||Zero||4.0 parts per trillion (ppt)|
|PFNAPFHxSPFHxSHFPO-DA and its ammonium saltPFBS||Hazard Index 1.0 (unitless)*||Hazard Index 1.0 (unitless)*|
* The total sum of each PFAS hazard quotient (determined by dividing the measured level of each of the four PFAS in drinking water by a health reference value for each PFAS).
The proposed regulations would require public water systems that detect PFAS above the MCLs to install treatment technology and would impose additional monitoring, recordkeeping and reporting requirements. Once finalized, the MCLs would become the national limits on PFOS and PFOA in drinking water, replacing the individual MCLs promulgated by states.
EPA is accepting written comments from interested persons following publication of the proposed rule in the Federal Register and will be holding a virtual public hearing on May 4, 2023 from 11 AM to 7 PM.