On February 8, 2024, the Environmental Protection Agency ("EPA") proposed two regulations that would add nine per- and polyfluoroalkyl substances ("PFAS") to the list of Resource Conservation and Recovery Act ("RCRA") "hazardous constituents" and broaden the definition of "hazardous waste" applicable to corrective action at waste facilities, which taken together, would significantly enhance EPA's authority to regulate PFAS.

Together the proposed rules would codify EPA's authority to prescribe corrective action for releases of these PFAS at corrective action sites and potentially open the door to eventually identifying solid waste containing designated PFAS as hazardous waste. These proposals are a direct response to the New Mexico governor's June 2021 petition requesting regulation of PFAS under RCRA. EPA foreshadowed its intent to propose these rules in its response to the petition in October 2021.

"Hazardous Waste" Definition Codified for Corrective Actions

EPA's first proposed rule would expand the regulatory definition of "hazardous waste" applicable to corrective action under RCRA applicable to treatment, storage, and disposal facilities ("TSD Facilities"). Currently, the regulatory definition of "hazardous waste" is limited to solid wastes that EPA has identified as listed or characteristic hazardous wastes. For purposes of corrective action only, and consistent with existing EPA guidance, the proposal would broaden the wastes subject to corrective action requirements to include any substance satisfying certain qualitative assessments under statutory definition of "hazardous waste."

For PFAS, this would allow EPA to require that qualifying releases of PFAS be addressed in corrective action even if the specific PFAS has not been identified as a characteristic or listed hazardous waste.

Nine New PFAS Deemed "Hazardous Constituents" Under RCRA

EPA's second proposed rule would expand the list of "hazardous constituents" under Appendix VIII of RCRA to include perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), perfluorohexanoic acid (PFHxA), and perfluorobutanoic acid (PFBA), along with their salts and structural isomers. If the proposal becomes a final rule, these PFAS would be among the hazardous constituents expressly identified for consideration in RCRA facility assessments when corrective action requirements are imposed and, where necessary, would require further investigation and cleanup through the RCRA corrective action process at TSD Facilities.

While being listed as a "hazardous constituent" does not place the listed PFAS within EPA's proposed definition of "hazardous waste," their presence in solid waste in sufficient concentrations may render the waste "hazardous waste" subject to EPA's corrective action authority. Additionally, EPA has specifically cited hazardous constituents as a basis for future regulation as a listed hazardous waste. In addition, listed hazardous wastes are automatically hazardous substances under the Comprehensive Environmental Response, Compensation and Liability Act ("CERCLA" or "Superfund"). CERCLA cleanups would then need to address any releases of the listed PFAS compounds, expanding the PFAS compounds to be addressed under CERCLA beyond EPA's proposed designation of PFOA and PFOS as CERCLA hazardous substances.

Comments on the expanded definition of "hazardous waste" are due by Thursday, March 7, 2024, and comments on the inclusion of the identified PFAS in Appendix VIII are due on Thursday, April 6, 2024.

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