The U.S. Environmental Protection Agency has proposed setting national drinking water standards for two of the most common and studied types of per- and polyfluoroalkyl (PFAS) chemicals under the Safe Drinking Water Act and is seeking comment on potential monitoring requirements and regulatory approaches for the chemicals.

The Feb. 20 proposal calls for establishing maximum contaminant levels for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). EPA also proposed regulating imported products that contain certain long-chain PFAS chemicals that are used as surface coatings. Under the proposal, EPA would place restrictions on imported goods that contain these chemicals. EPA Administrator Andrew Wheeler said the proposal would “close a loophole that currently allows new uses of products that include certain PFAS chemicals…that have been phased out of the United States to be imported into our country.”

PFAS chemicals, at one time commonly found in household products such as Teflon and Scotchgard, as well as in firefighting foam at military bases, are a growing concern because of their prevalence in drinking water systems and groundwater. An Environmental Working Group Study released in January found that out of 44 test samples in 31 states and the District of Columbia, only one location had no detectable levels of PFAS. PFAS has been associated with different types of cancer and thyroid problems.

Federal lawmakers held multiple congressional hearings last year and included in the 2020 defense authorization bill provisions that would have required EPA to regulate PFAS under the Safe Drinking Water Act and to declare the chemicals as “hazardous” under the nation’s Superfund law. But those provisions were stripped during conference negotiations under threat of a presidential veto.

Seth Michaels, a spokesperson for the Union of Concerned Scientists, says EPA’s action is a positive development that is “long overdue. We’ll be watching this closely to make sure that the PFAS policy we get is effective, serious and grounded in science.”

Environmental Working Group’s legislative attorney Melanie Benesch had a stronger reaction: “EPA has wasted decades deciding whether to regulate PFAS and they could take many more years before a drinking water standard is finalized.”

Groups such as the American Water Works Association (AWWA) and the American Council of Engineering Companies (ACEC) have said that there is insufficient science-based research to determine at what levels PFAS is harmful to human health or the environment, and which, out of the 4,000 known PFAS chemicals, are harmful. AWWA and ACEC have advocated regulating individual chemicals, including PFOA and PFOS, rather than the entire class, until more research has been conducted.

The public will have 60 days to comment on the proposals once they are published in the Federal Register.