MassDEP will develop a drinking water maximum contaminant level (MCL) for per- and polyfluoroalkyl substances, known as PFAS, in response to the Conservation Law Foundation’s October 25, 2018 petition, which we reported on earlier. While MassDEP largely rejected the petition’s specific requests, including a call for an emergency interim MCL, MassDEP’s January 28, 2019 response instead outlined a broader, longer-term plan to address PFAS substances in drinking water.

Although MassDEP will establish a drinking water MCL for PFAS, it will not do so for PFAS as a class, as suggested by some stakeholders. Instead, MassDEP will focus on a subset of PFAS compounds that are a threat to human health, are detectable, and can be treated with available technology. MassDEP identified these compounds as PFOA, PFOS, PFHxS, PFHpA, and PFNA. In explaining its decision to narrow the regulatory scope, MassDEP cited the significant expense of treating drinking water for PFAS contamination, how little is known about the vast majority of the more than 3,000 PFAS compounds, and the limited treatment technologies available.

MassDEP’s response also acknowledged a plan to develop reportable concentrations and cleanup standards for PFAS under the Massachusetts Contingency Plan. MassDEP will work with the Waste Site Cleanup Advisory Committee to develop a regulatory approach, as well as solicit public comment.

The petition, and several stakeholders at the public meeting on January 18, 2019, requested MassDEP begin statewide testing for PFAS contamination in drinking water. In its response, MassDEP promised to develop a “targeted sampling program” to test public water sources near known or potential sources of PFAS contamination. The public will be informed of future testing via online posts.

MassDEP noted that its approach to developing the new PFAS regulations will evolve. The department committed to engaging stakeholders and monitoring the growth of PFAS-related scientific knowledge. MassDEP did not provide a timeline for the drinking water MCL rulemaking process.

Regulation of PFAS was also in the national news this week. According to multiple news outlets, the U.S. EPA has decided not to regulate PFOA and PFOS via the Safe Drinking Water Act. There is no national MCL for any other compound in the PFAS class either. With no national standard on the horizon and growing public concern, more states may decide to pursue their own regulatory solutions.