Trump EPA takes last-minute actions on PFAS

In the waning hours of the Trump administration, the US Environmental Protection Agency pushed out a raft of decisions affecting per- and polyfluoroalkyl substances (PFAS).

Notably, the EPA took a key step toward limiting the amount of two widespread PFAS in drinking water: perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). These two compounds, no longer produced in the US, were used for decades in firefighting foams and are often found in groundwater near military bases, airports, and training facilities for firefighters. Like many other PFAS, they are toxic and generally don’t break down in the environment.

The agency made a final determination Jan. 19 that it needs to regulate the two substances under the Safe Drinking Water Act. Next, the EPA must go through a years-long, congressionally mandated process before it can finalize a legally enforceable limit on PFOA and PFOS in drinking water.

The EPA also asked for public comment on whether it should require additional regulation of PFOA, PFOS, and unspecified other PFAS as hazardous waste under the Resource Conservation and Recovery Act. The agency also asked for feedback on whether to designate these substances hazardous under the Superfund law. That designation would allow the government to clean up contaminated land or groundwater and then seek reimbursement from polluters.

In addition, the EPA finalized a controversial toxicity assessment of perfluorobutane sulfonic acid (PFBS), a substance that 3M introduced to replace PFOS-based surfactants. It is used as a processing aid in the manufacture of fluoropolymers.

Trump administration officials overrode the conclusions of EPA staff toxicologists and set a safe daily dose for long-term exposure of between 0.0003 and 0.001 mg of PFBS per kilogram of body weight per day. This is equivalent to 1,100–3,700 parts per trillion in drinking water, says Laurel Schaider, a research scientist at the Silent Spring Institute, a research group.

The numerical range affects state regulators that rely on the EPA’s scientific expertise when they establish PFBS cleanup requirements. They will face pressure to use the higher number from polluters wanting to reduce their liability, environmental advocates say.