On February 8, 2024, U.S. EPA proposed two new significant regulations that would expand its authority to require cleanup of per- and polyfluoroalkyl substances (PFAS) under the Resource Conservation and Recovery Act (RCRA).  The scope of the proposed regulations and the potential facilities affected are discussed below.

Background on RCRA Program

To understand the potential scope of the new proposed regulations it is important to understand two basic aspects of regulatory frameworks under RCRA.

  1. Subtitle C (Management of Hazardous Waste)– Under Subtitle C of RCRA, EPA regulates hazardous waste from “cradle-to-grave,” which means all aspects of management of hazardous waste.  Subtitle C applies to facilities that transfer, store, and dispose of hazardous waste (referred to as TSDFs). Facilities subject to Subtitle C have cleanup obligations if there is a release of hazardous waste at a Subtitle C facility. A RCRA unit at a facility that had a release of hazardous waste is subject to RCRA Closure.
  2. RCRA’s Corrective Action Program (Cleanup Authority)- The RCRA Corrective Action program expands the reach of EPA’s cleanup authority under RCRA beyond the unit to site-wide.  Facilities subject to RCRA Corrective Action include the following:
    • Solid Waste Management Units or SWMUs– Based upon EPA guidance, a SWMU is “any unit at a facility from which hazardous constituents might migrate, irrespective of whether the units were intended for the management of solid and/ or hazardous wastes.” EPA provides the following examples of SWMUs: container storage areas, tanks, surface impoundment, waste piles, land treatment units, landfills, incinerators, underground injection wells and other physical, chemical and biological treatment units.
    • Hazardous Waste Constituents–   In addition to any cleanup of hazardous waste released, EPA can require investigation and cleanup of constituents designated as “hazardous constituents.”  As discussed below, with the Listing Rule, EPA is proposing to list nine PFAS compounds as “hazardous constituents” which is a lower technical bar than listing as a “hazardous waste.” 

Process to Designate a Compound as a “Hazardous Waste”

In order to better understand both the RCRA Listing Rule and Definition Rule, it is important to understand the regulatory process for listing a substance as either a “hazardous waste” or a “hazardous constituent” under RCRA. 

Hazardous waste determinations are complex and technical.  Current RCRA regulations limit the definition of “hazardous waste” to include only compounds that are either explicitly listed as a hazardous waste through formal rulemaking (so called “listed hazardous wastes”) or that meet one of four characteristics: ignitability, corrosivity, reactivity, or toxicity (so called “characteristic hazardous wastes”). 

Under RCRA, EPA must go through a rule-making procedure that considers several enumerated factors in listing a compound as a “hazardous waste.”  Ultimately, in considering the factors, EPA must determine if the substance is capable of posing “a substantial present or potential threat to human health or the environment when improperly treated, stored, transported, disposed of, or otherwise managed.” 

The regulatory burden to list a compound as a “hazardous constituent” is lower than listing a compound as a hazardous waste.  A “hazardous constituent” is a chemical that has “toxic, carcinogenic, mutagenic or teratogenic effects on humans or other life forms,” but has not yet been designated as a hazardous waste under RCRA.

Compounds that are considered “hazardous wastes” are automatically hazardous substances under CERCLA. “Hazardous constituents” are not automatically designated as “hazardous substances” under CERCLA.   

Under both proposed rules, EPA is not yet designating any PFAS compound as a hazardous waste. Although, EPA says the proposed Listing Rule is the first step in the process to designate PFAS as a hazardous waste subject to Subtitle C. 

Listing Rule – Listing of Nine Specific PFAS as Hazardous Constituents

EPA proposes to identify the following nine PFAS compounds as “hazardous constituents” under RCRA:

  • 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),
  • perfluorobutanoic acid (PFBA),
  • along with their salts and structural isomers.

By adding these PFAS compounds to the list of “hazardous constituents” it would provide U.S. EPA and states with delegated authority to force the investigation and cleanup of PFAS at RCRA TSDFs.  TSDFs that have accepted hazardous wastes and have had releases may be required to investigate for the presence of these nine PFAS chemicals and take corrective action both on-site and off-site if the chemicals are present.  This would include TSDFs where a prior RCRA Corrective Action was completed.  Such sites could be reopened to require investigation or cleanup of PFAS.

Definition Rule – Definition of Hazardous Waste Applicable to Corrective Action for Releases at TSDFs

EPA is proposing to expand its own regulatory authority to address so called “emerging contaminants” (not just PFAS compounds) before EPA decides to embark on the more extensive regulatory process of listing an emerging contaminant as a “hazardous waste.”   As discussed above, current RCRA regulations require EPA to either: 1) list a substance as a hazardous waste if meets certain enumerated factors; or 2) determine the compound is characteristic hazardous waste; or 3) go through formal rulemaking, such as the Listing Rule, to designate a compound a “hazardous constituent.” 

The statutory definition of hazardous waste under 42 U.S.C. § 6903(5) encompasses any solid waste that:

  • May cause, or significantly contribute to an increase in mortality or an increase in serious, irreversible, or incapacitating reversible, illness or
  • Pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed.

By replacing the current RCRA regulatory definition of “hazardous waste” with the statutory definition, EPA would have broader regulatory authority to regulate emerging contaminants without having to go through the complex regulatory process of designating such compound as a hazardous waste or even designating it a hazardous constituent. 

EPA’s proposed Definition Rule is more controversial than the Listing Rule because it is meant to provide EPA broader regulatory authority to address any so called “emerging contaminant”, not just PFAS.  It allows EPA to begin regulating such compounds so long as it makes a determination (without a formal rulemaking) that the compound meets the statutory definition of a “hazardous waste.”   EPA asserts it already has this authority since it simply would be incorporating the statutory definition into regulation.   

In addition, the Definition Rule is also more controversial because it has the potential to affect permitting of facilities under RCRA, thereby giving EPA potentially broader authority to regulate emerging contaminants through permits.  In order to regulate an emerging contaminant during the RCRA permitting process, a permit writer for a RCRA TSDF would need to develop and present for public comment, an administrative record supporting its conclusion that the substance meets the statutory hazardous waste definition.  Currently, EPA could not include requirements for emerging contaminants in TSDF permits that have not been formally designated a hazardous waste. 

Sites Potentially Affected – RCRA Proposed PFAS Rules vs. CERCLA Proposed PFAS Rules

The universe of potential sites affected by the RCRA Listing is much smaller than the pending designation of PFAS as a “hazardous substance” under CERCLA. Entities potentially affected by Listing Rule 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. If EPA finalizes the designation of PFOS and PFOA as “hazardous substances” under CERCLA, any location where a release of PFOS or PFOA occurred could be required to perform a CERCLA cleanup.

In the proposed rule, EPA estimates that up to 1,740 facilities could be subject to Corrective Action requirements because of the Listing Rule. EPA even broke this number down by North American Industry Classification System (NAICS) number which is used by federal agencies to classify business establishments. EPA determined that the three most common industries in the regulatory universe account for approximately 54 percent of facilities. These industries include waste management and remediation services (NAICS 562), chemical manufacturing (NAICS 325), and national security and international affairs (NAICS 928). Overall, facilities across the manufacturing sector (NAICS codes 311 to 339) account for 46 percent of the potentially regulated facilities. Within the manufacturing sector, 41 percent of manufacturing facilities are in chemical manufacturing.