Designation of PFOA and PFOS as Hazardous Substances Under CERCLA Proposed by EPA

The U.S. Environmental Protection Agency (EPA) is proposing the designation of two per- and polyfluoroalkyl substances (PFAS) as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The chemicals, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), are two of the most extensively used PFAS, and ones that have been shown to pose particularly significant risks to the environment and human health. In this blog post, we review the focus of CERCLA and consider the proposed designations.

Comprehensive Environmental Response, Compensation, and Liability Act

CERCLA was enacted by the U.S. Government more than four decades ago, in December 1980. Also known as the Superfund law, the Act is focused on the cleanup of emergency environmental contaminant releases. It also allows the EPA to obligate responsible parties to clean up contaminated sites (or reimburse the Agency in cases where it conducts the cleanup efforts itself).

CERCLA permits two key types of response actions (the latter of which is only permitted at National Priorities List sites):

  • Removal actions (short-term) in response to existing or likely hazardous substance releases necessitating a rapid response
  • Remedial response actions (long-term) designed to decrease dangers related to existing or likely hazardous substance releases (ones considered to be serious, but not life-threatening)

CERCLA was notably amended in October 1986 via the Superfund Amendments and Reauthorization Act.


As part of the larger group of chemicals known as PFAS, the chemical composition of PFOA and PFOS makes them highly resistant to degradation and contributes to their environmental persistence.


IUPAC Name2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoic acid
Chemical FormulaC8HF15O2
CAS Registry Number335-67-1


IUPAC Name1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluorooctane-1-sulfonic acid
Chemical FormulaC8HF17O3S
CAS Registry Number1763-23-1

PFAS are known to present a variety of human health risks. Among these are hypertension, kidney cancer, low birth weight and immunotoxicity (in children), testicular cancer, thyroid disease, and more. Research continues to be conducted to understand the full range of hazards posed by PFOA, PFOS, and other PFAS chemicals.

Proposed Designation as Hazardous Substances

The proposal to designate PFOA and PFOS as hazardous substances under CERCLA aligns with the goals of the EPA's PFAS Strategic Roadmap. A principal focus of this roadmap is to establish timeframes in which the Agency plans to implement actions geared toward the protection against contamination from per- and polyfluoroalkyl substances. Upon finalization of the designation, it will be necessary for PFOA and PFOS releases (at or in excess of reportable quantities) to be reported to the National Response Center and other relevant groups and authorities. A finalized rule would likely facilitate improved waste treatment and management processes for facilities that use or handle these PFAS chemicals.

Additional Information

More information regarding the proposed designations for PFOA and PFOS may be found on the EPA’s website as it becomes available. Additionally, you can visit the ToxPlanet website and blog regularly for information on new developments.

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