Following the EPA’s proposed designation of PFOA, PFOS, and their salts and structural isomers, as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, otherwise known as Superfund) on Sept. 6, 2022, EPA has just published an advanced notice of proposed rulemaking to evaluate whether to designate a number of additional PFAS chemicals as hazardous substances under section 102(a) of CERCLA.

The advance notice of proposed rulemaking, announced on April 12 and published on April 13, seeks input and data concerning seven PFAS and their salts and structural isomers, or some subset thereof, as hazardous substances under CERCLA. The seven PFAS are:

• Perfluorobutanesulfonic acid (PFBS), CASRN 375–73–5;
• Perfluorohexanesulfonic acid (PFHxS), CASRN 355–46–4;
• Perfluorononanoic acid (PFNA), CASRN 375–95–1;
• Hexafluoropropylene oxide dimer acid (HFPO–DA), CASRN 13252–13–6 (sometimes called GenX);
• Perfluorobutanoic acid (PFBA) CASRN 375–22–4;
• Perfluorohexanoic acid (PFHxA) CASRN 307–24–4; and
• Perfluorodecanoic acid (PFDA) CASRN 335–76–2.

EPA is also soliciting input regarding the designation of precursors to PFOA, PFOS, PFBS, PFHxS, PFNA, HFPO-DA, PFBA, PFHxA, and PFDA. EPA will use the comments and data received to evaluate whether it will initiate formal rulemaking to designate the seven PFAS chemicals or their salts, isomers, or precursors as hazardous substances under CERCLA.

EPA’s earlier proposal to list PFOA and PFOS has attracted substantial opposition from the industry (subscription required). It is very likely that this advanced notice of proposed rulemaking will be met with similar opposition.

The complete advanced notice of proposed rulemaking is available here. Comments to EPA must be received on or before June 12, 2023.