The U.S. Environmental Protection Agency could expand the number of “forever” chemicals that would be deemed hazardous and face cleanup under the nation’s Superfund law.

The announcement is part of the agency’s efforts to address pollution caused by the chemicals known as PFAS—per- and polyfluoroalkyl substances—a class of nearly ubiquitous chemical compounds known to endanger human health. EPA proposed designating the two most studied and common types of PFAS—perfluorooctanoic acid (PFOA) and perfluoroocanesulfonic acid (PFOS) as hazardous substances under the Comprehensive Environmental Response, Compensation and Liability Act last September.  

In an advanced notice of proposed rulemaking published on April 13, EPA said it seeks comment on adding more types of PFAS, including HFPO-DA, sometimes called GenX, to the list of hazardous substances under that law. It also seeks input on whether some PFAS compounds can or should be designated as a group or category. 

The announcement “highlights EPA's commitment to transparency and the use of the best available science to tackle PFAS pollution and protect people from exposure to these forever chemicals,” said Barry Breen, acting assistant administrator for EPA’s Office of Land and Emergency Management in a statement. President Biden has not yet nominated a candidate to head the EPA office, which oversees Superfund cleanups. 

Although environmental groups such as the Environmental Working Group, which has long highlighted the dangers of PFAS to public health and the environment, cheered the announcement, water sector groups say they are worried about costs and potential liability. 

In comments submitted to EPA in November regarding designating PFOA and PFOS as hazardous, the American Water Works Association noted that the agency has not adequately considered the costs to small municipal systems, which comprise the bulk of drinking water systems. 

Also, despite EPA assurances that adverse impacts on public water systems would be avoided by agency officials' “enforcement discretion,” the agency said “a review of historical sites has demonstrated that this is not a shield of protection.” In 1993. a sewage treatment facility was held liable under the Superfund law for a hazardous substance present in the wastewater system and released through leaky pipes, the water agency trade group said. 

EPA will accept comments on the advanced notice of proposed rulemaking through June 12. If it decides ultimately to designate additional types of PFAS as hazardous substances, it will publish a proposed rule and seek public comment.