The record-low health advisories form part of the EPA’s 2021 PFAS Strategic Roadmap, which forecasts further regulatory action at both state and federal levels.

By Julia Hatcher, Kegan A. Brown, Thomas C. Pearce, Taylor West, Andy Landolfi, and Phil Sandick

On June 15, 2022, the United States Environmental Protection Agency (EPA) issued interim, updated drinking water health advisories (HA) for two of the most common per- and polyfluoroalkyl substances (PFAS): perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).[1] EPA also issued two final HAs for perfluorobutane sulfonic acid and its potassium salt (PFBS) and hexafluoropropylene oxide and its ammonium salt (GenX).[2]

Record Low HAs for Certain PFAS

The updated lifetime drinking water HAs for PFOA and PFOS are near zero: 4 parts per quadrillion (ppq) for PFOA and 20 ppq for PFOS. In its June 15 press release, EPA states that these updated HAs “indicate that some negative health effects may occur with concentrations of PFOA or PFOS in water that are near zero and below EPA’s ability to detect at this time.” These updated drinking water HAs for PFOA and PFOS are, respectively, 4 and 3 orders of magnitude lower than the prior HAs of 70 parts per trillion (ppt) EPA established for both compounds in 2016. Although the new HAs are based on “lifetime” exposure scenarios, EPA has stated that the HAs for PFOS and PFOA also apply to short-term exposure scenarios because the key adverse effect identified for PFOA and PFOS is a developmental effect that can potentially result from short-term exposure during a critical period of development.[3]

EPA’s June 15 announcement also established lifetime drinking water HAs of 2,000 ppt for PFBS and 10 ppt for GenX. Generally, GenX has been used as the replacement compound for PFOA, and PFBS has been used as the replacement compound for PFOS. Both of these compounds are in current replacement manufacture, processing, and use applications in the US and elsewhere, therefore the drinking water HAs for these compounds potentially call into question the safety profile of these commercial activities. Notably, the lifetime drinking water HA for GenX is seven times lower than the prior HA level for PFOA.

Health Advisories Generally

Under the Safe Drinking Water Act, EPA has the authority to issue HAs for chemicals of concern that are not currently subject to enforceable drinking water quality standards. Though HAs are not legally binding, EPA often uses them to provide regulators and drinking water suppliers with timely technical information on chemical contaminants known to be present (or that may be present) in drinking water. HAs also identify the concentration of a contaminant in drinking water below which EPA believes adverse health effects are not anticipated to occur over a particular exposure duration. Notably, state and local regulatory authorities may rely on HAs for their own monitoring programs to identify contaminant issues requiring remediation and other action.

The Road Ahead

The HAs for PFOA and PFOS are characterized as interim, consistent with EPA’s intention to move forward with a PFAS National Drinking Water Regulation rather than issue final HAs. EPA is currently planning to issue a proposed drinking water rule at some point this fall. Under this approach, the interim HAs would remain in place until EPA issues a final rule, which is expected in 2024.

The new HAs are part of a broader set of regulatory initiatives set forth in EPA’s 2021 PFAS Strategic Roadmap; additional regulatory action is expected in the near-term at both the state and federal levels. For example, EPA is expected to designate PFOA and PFOS as “hazardous substances” under the Comprehensive Environmental Response, Compensation, and Liability Act. Such designation would have significant implications for entities that have ever manufactured, processed, used, or distributed PFOA and PFOS (including as a component of finished products), and would likely lead to extensive investigation and remediation obligations at both current and potentially closed contaminated sites.

Further Updates

Latham will continue to monitor developments in this area, and readers are encouraged to subscribe to Latham’s Environment, Land & Resources blog to receive the latest updates.  Latham will also soon issue a Client Alert with further details on the science behind these HAs and more detailed discussion of their likely implications, including the potential for them to:

  • Trigger additional investigation and remediation actions
  • Serve as a catalyst for additional PFAS litigation of various types, including with reference to products that currently do (or may) contain any of these four PFAS
  • Result in additional laws and regulations restricting PFAS in commerce, particularly at the state level, along the lines of what has been enacted or is being considered in Maine, Massachusetts, Colorado, and California
  • Have impacts outside of the US, including with reference to the current European Union PFAS evaluation



[1] U.S. Envtl. Prot. Agency, Drinking Water Health Advisories for PFOA and PFOS: 2022 Interim Updated PFOA and PFOS Health Advisories (June 15, 2022),

[2] U.S. Envtl. Prot. Agency, Drinking Water Health Advisories for GenX Chemicals and PFBS: 2022 Final Health Advisories for GenX Chemicals and PFBS (June 15, 2022),

[3] U.S. Envtl. Prot. Agency, Interim Drinking Water Health Advisory: Perfluorooctane Sulfonic Acid (PFOS) CASRN 1763-23-1, at 6 (June 2022); see also U.S. Envtl. Prot. Agency: Interim Drinking Water Health Advisory: Perfluorooctanoic Acid (PFOA) CASRN 335-67-1, at 6 (June 2022).