EPA Proposes 9 PFAS Hazardous Constituents Under RCRA
February 7, 2024
Proposed PFAS Hazardous Constituents Under RCRA
The Environmental Protection Agency (EPA) is proposing to amend its regulation under the Resource Conservation and Recovery Act (RCRA) by adding nine specific per-and polyfluoroalkyl substances (PFAS), their salts, and their structural isomers to its list of hazardous constituents. EPA’s criteria for listing substances as hazardous constituents under RCRA require that they have been shown in scientific studies to have toxic, carcinogenic, mutagenic, or teratogenic effects on humans or other life forms.
Entities potentially affected by this action include hazardous waste treatment, storage, and disposal facilities (TSDFs) with solid waste management units (SWMUs) that have released or could release any of the PFAS proposed to be listed as RCRA hazardous constituents. EPA has identified 1,740 such facilities, which could be subject to additional corrective action requirements (under RCRA section 3004(u) and (v)) to address releases not already subject to corrective action under EPA’s corrective action regulations.
The nine PFAS and common uses are as follows:
Perfluorooctanoic acid (PFOA; CASRN 335-67-1). PFOA is an eight-carbon molecule with seven fully fluorinated carbon atoms, and one carboxylic acid functional group used as a processing aid to produce fluoropolymers found in cleaning agents, waxes, aqueous film-forming foam (AFFF), and other products.
Perfluorooctanesulfonic acid (PFOS; CASRN 1763-23-1). PFOS is a fully fluorinated eight-carbon molecule with one sulfonic acid functional group used in AFFF surface treatments of textiles to provide oil and water resistance, metal plating, and other uses and industries.
Perfluorobutanesulfonic acid (PFBS; CASRN 375-73-5). PFBS is a fully fluorinated four-carbon molecule with one sulfonic acid group. It has been used as a replacement for PFOS used in manufacturing paints and cleaning agents, metal plating, AFFF, to provide oil and water resistance, and other uses and industries.
Hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX; CASRN 13252-13-6). HFPODA is a six-carbon molecule consisting of five fully fluorinated carbon atoms, one ether functional group, and one carboxylic acid functional group. HFPO-DA is a chemical associated with GenX processing aid technology used to make fluoropolymers without PFOA.
Perfluorononanoic acid (PFNA; CASRN 375-95-1). PFNA is a nine-carbon molecule with eight fully fluorinated carbon atoms and one carboxylic acid functional group. It has been used as a processing aid to produce fluoropolymers and has been used or found in metal plating, cleaning agents, waxes, AFFF, energetic materials, and other products.
Perfluorohexanesulfonic acid (PFHxS; CASRN 355-46-4). PFHxS is a fully fluorinated six-carbon molecule with one sulfonic acid functional group used in AFFF surface treatments of textiles to provide oil and water resistance, in metal plating, and in other uses and industries.
Perfluorodecanoic acid (PFDA; CASRN 335-76-2). PFDA is a ten-carbon molecule with nine fully fluorinated carbon atoms and a carboxylic acid functional group. It has been used as a processing aid to produce fluoropolymers and has been used or found in metal plating solutions, cleaning agents, waxes, AFFF, and other products.
Perfluorohexanoic acid (PFHxA; CASRN 307-24-4). PFHxA is a six-carbon molecule with five fully fluorinated carbon atoms and a carboxylic acid functional group. It has been used or found in metal plating solutions, cleaning agents, waxes, AFFF, and other products.
Perfluorobutanoic acid (PFBA; CASRN 375-22-4). PFBA is a four-carbon molecule with three fully fluorinated carbon atoms and one carboxylic acid functional group. It has been used or found in metal plating, cleaning agents, waxes, AFFF, energetic materials, and other products.
EPA will collect comments on this PFAS to RCRA’s hazardous constituents proposal for 60 days once published in the Federal Register. Read a prepublication copy of this proposal.
Submit your comments on the Federal eRulemaking Portal: https://www.regulations.gov and identified by Docket ID No. EPA-HQ-OLEM-2023-0278.
As a result of this proposed rule, if finalized, when imposing corrective action requirements at a facility, these PFAS would be among the hazardous constituents expressly identified for consideration in RCRA facility assessments and, where necessary, further investigation and cleanup through the RCRA corrective action process at RCRA treatment, storage, and disposal facilities. Contact SCS Engineers for guidance about your facility at .
Additional Resources:
For additional information regarding EPA’s proposed RCRA PFAS rules, see:
