March 18, 2024

Proposals on the Definition of Hazardous Waste and PFAS as Hazardous Constituents

Definition of Hazardous Waste Applicable to Corrective Action

On February 8, 2024, EPA proposed a rule to amend the definition of hazardous waste applicable to corrective action. [89 FR 8598] The current definition of hazardous waste in §260.10 refers to the definition in §261.3—solid wastes that meet a listing description and/or exhibit a characteristic—and consequently applies the regulatory definition throughout Parts 260 through 273. The proposed rule would add the more broadly written RCRA Section 1004(5) statutory definition of hazardous waste throughout key regulatory sections defining hazardous wastes. Through a series of cross-references, the change will be incorporated into §264.101 and Part 264, Subpart S corrective action requirements, thus expanding the scope of corrective action to statutorily defined hazardous waste.

The RCRA Section 1004(5) statutory definition of hazardous waste is:

“The term ‘hazardous waste’ means a solid waste, or combination of solid wastes, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may: (A) cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (B) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed.”

EPA believes this amendment will provide clear authority to address the full universe of substances the statute intended. Despite the seemingly expanding scope of the corrective action program, the agency does not expect the rule to result in an increase in permit conditions, as the rule merely codifies longstanding guidance on the applicability of the statutory definition of hazardous waste to corrective action. [89 FR 8602–8603] Comments may be submitted through March 26, 2024 via Docket ID No. EPA-HQ-OLEM-2023-0085. [89 FR 15967]

Listing of Specific PFAS as Hazardous Constituents

The agency issued a second proposal on February 8, this one to list nine specific PFAS chemicals as RCRA hazardous constituents. [89 FR 8606] A hazardous constituent listing in Part 261, Appendix VIII is a step toward designating that constituent, or a waste containing that constituent, as a hazardous waste. This rule would expand the corrective action requirements to include these PFAS chemicals during RCRA facility assessments and corrective action cleanups and pave the way for designating them as hazardous waste.

List of Nine PFAS Chemicals Proposed for RCRA Hazardous Constituent Designation

Chemical Name


CAS Number

Perfluorooctanoic acid



Perfluorooctanesulfonic acid



Perfluorobutanesulfonic acid



Hexafluoropropylene oxide-dimer acid



Perfluorononanoic acid



Perfluorohexanesulfonic acid



Perfluorodecanoic acid



Perfluorohexanoic acid



Perfluorobutanoic acid



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EPA identified at least 1,740 facilities that could be subject to additional corrective action requirements due to this rule. As the rule would be promulgated under the Hazardous and Solid Waste Amendments of 1984, it would take effect immediately in all states. Comments may be submitted through April 8, 2024 via Docket ID No. EPA-HQ-OLEM-2023-0278.


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This document addresses issues of a general nature related to the federal RCRA regulations. Persons evaluating specific circumstances dealing with the RCRA regulations should review state and local laws and regulations, which may be more stringent than federal requirements. In addition, the assistance of a qualified professional should be enlisted to address any site-specific circumstances.