Near Zero: EPA Sets New Stringent PFAS Lifetime Health Advisories

June 17, 2022

In its latest action under its PFAS Roadmap, the US Environmental Protection Agency issued new and updated drinking water health advisories for four PFAS chemicals. These health advisories are an interim step in a larger process of regulation for PFAS at the federal level and arrive at a time of unprecedented state and federal regulatory and legislative action to address PFAS in the environment.

On June 15, the Environmental Protection Agency (EPA) released significantly reduced lifetime drinking water health advisory levels (HALs) for four per- and polyfluoroalkyl substances (PFAS) under its Safe Drinking Water Act (SDWA) authority. These include revised interim levels for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) along with new, final limits for perfluorobutane sulfonic acid (PFBS) and hexafluoropropylene oxide dimer acid and its ammonium salts, collectively known as GenX.

Lifetime health advisory levels identify the concentration of chemicals in drinking water over an individual’s lifetime at or below which adverse health effects are not anticipated to occur. Although HALs are not enforceable standards and are non-regulatory, they can be used in the development of drinking water regulations and limits, influence state and local regulations, and shape public debate around the safety of particular chemicals.

Newly Announced PFAS HALs

  • Interim updated Health Advisory for PFOA = 0.004 ppt
  • Interim updated Health Advisory for PFOS = 0.02 ppt
  • Final Health Advisory for GenX chemicals = 10 ppt
  • Final Health Advisory for PFBS = 2,000 ppt

EPA issued these new values for PFOA and PFOS as “interim” advisories, acknowledging that they are based upon new toxicity data and draft analyses that are currently under review by the Agency’s Science Advisory Board, and that additional new data is likely to become available. The health advisories are intended to remain in place until EPA’s forthcoming PFAS National Primary Drinking Water Regulation goes into effect, unless otherwise updated by EPA.

EPA set interim advisory levels of 0.004 parts per trillion (ppt) for PFOA—or four parts per quadrillion (ppq) —and 0.02 ppt—or 20 ppq—for PFOS. To put this into perspective, one part per quadrillion is equivalent to one drop of water in a cube of water measuring approximately 368 meters on a side and about as tall as the Empire State Building, or one second of time in approximately 31.7 million years. EPA’s new interim PFOA and PFOS HALs replace the Obama-era guidance values of 70 ppt for PFOA and PFOS individually or combined set by EPA in 2016.

EPA’s new final health advisories for PFBS and GenX chemicals—which are generally considered replacements for PFOS and PFOA, respectively, in chemical and product manufacturing—set lifetime exposure levels at 2,000 ppt for PFBS and 10 ppt for GenX. These final HALs are based on EPA’s final 2021 animal toxicity studies for PFBS and GenX chemicals. Unlike the advisories for PFOA and PFOS, EPA announced that the PFBS and GenX advisories are final.


EPA’s newly announced HALs will impact the development of future federal and state regulation, identification and cleanup of contaminated sites, foreshadow potential litigation trends, and be a signal for industries dealing with PFAS of EPA’s possible approach to future regulation and guidance. The updated advisories for PFOA and PFOS are orders of magnitude lower than those identified by EPA in 2016, and its HALs for GenX and PFBS reflect EPA’s intent to aggressively address potential PFAS exposure.

These updated health advisories are also an interim step in a larger process of regulation for PFOA and PFOS at the federal level and come against the backdrop of unprecedented state regulatory and legislative action as dozens of states are actively considering laws and policies to address PFAS contamination. Under EPA’s PFAS Roadmap, EPA is anticipated to propose a rule in the fall of 2022 (with a final rule anticipated in fall 2023) to establish a National Primary Drinking Water Regulation (NPDWR) for PFOA and PFOS that would set enforceable limits and require monitoring of public water supplies. While the criteria EPA must consider when setting enforceable standards under the SDWA differ from those for issuing HALs (for example, EPA must consider economic factors when proposing NPDWRs), EPA’s updated interim guidance for PFOA and PFOS signal that we can expect EPA to act aggressively in setting enforceable limits.

Additionally, the newly announced HALs may galvanize the push for more stringent cleanup requirements across the country, while also acting as a springboard for stricter enforcement at the state level. Because HALs (both interim and final) are not enforceable standards, they would not be considered Applicable or Relevant and Appropriate Requirements (ARARs) under CERCLA, but they may be referenced as “TBC” (to be considered), similar to a guidance document.

Accordingly, these advisories could inform remediation levels not just in future cleanups, but also in cleanups that are currently underway. At the federal level, historic PFAS advisories have been adopted as interim groundwater cleanup recommendations by the Office of Land and Emergency Management, and the 70 ppt level has been used as a guidepost by the US military for its cleanups. Many states adopted EPA’s non-enforceable lifetime health advisory levels of 70 ppt for PFOA and PFOS (e.g., Colorado, Ohio) or took no formal action and simply relied on EPA’s HALs as de facto standards. States that have issued criteria for addressing GenX chemicals are at concentration levels significantly above those of EPA’s new HAL (e.g., North Carolina’s provisional health goal of 140 ppt for GenX). Other states (e.g., New Jersey and Vermont) went a step further and set standards, which would be ARARs, that are lower than former HALs but higher than the new HALs.[1] Responsible parties and regulators will need to grapple with the impacts of EPA’s new HALs.

These new health advisory levels also present questions about the long-term usefulness of the Regional Screening Levels (RSLs) and Regional Removal Management Levels (RMLs) recently revised by EPA’s Office of Land and Emergency Management for five PFAS, including PFOA, PFOS and GenX. Regulated entities can expect the RSLs and RMLs to be adjusted in the next semi-annual update.

Finally, it remains to be seen how these newly reduced advisories will work in practice given current limitations on testing (such as laboratory detection limits and methods) and treatment capabilities. For instance, under currently approved analytical methods, detection limits for PFOA and PFOS are 4 ppt—1000x and 200x above EPA’s interim HALs for PFOA and PFOS, respectively. In its statements following the announcement of the new HALs, EPA acknowledges the limitations of currently approved testing and detection methods,[2] but in turn has stressed to regulated parties that the advisories are not detection levels.

It will be paramount for stakeholders to continue to monitor both state and federal actions and guidance and to assess operations as states and interested and regulated parties continue to assess the impacts of the new advisories.


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[1] EPA’s 2016 health advisories for PFOA and PFOS were not without criticism both at the state and federal level in the aftermath of their announcement, including the Agency for Toxic Substances and Disease Registry’s findings suggesting that EPA’s advisory of 70 ppt may be too high.

[2] “Based on current methods, the health advisory levels for PFOA and PFOS are below the level of both detection (determining whether or not a substance is present) and quantitation (the ability to reliably determine how much of a substance is present). This means that it is possible for PFOA or PFOS to be present in drinking water at levels that exceed health advisories even if testing indicates no level of these chemicals.” EPA, Questions and Answers: Drinking Water Health Advisories for PFOA, PFOS, GenX Chemicals and PFBS.