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Are PFAS Air Emission Regulations on the Horizon?

While much of recent federal per- and polyfluoroalkyl substances (“PFAS”) regulatory activity has focused on water supply and soil contamination of PFAS compounds, the Environmental Protection Agency’s (“EPA”) ongoing research and policy initiatives may be laying the groundwork for potential air emissions regulations in the future. The newly formed EPA Council on PFAS has been directed by EPA Administrator Michael Regan to incorporate air quality considerations into its five year strategy.1 And a 2020 study conducted by researchers and engineers at Ohio State University in partnership with the EPA concluded that air emission pathways contribute to current and historical water and soil proliferation of PFAS in Ohio and West Virginia.2 It seems possible, therefore, that the EPA could begin developing federal air emissions regulations for specific PFAS compounds at some point over the next several years. However, the EPA will need to address various gaps in the current scientific understanding of these compounds to move forward with such regulations. In the absence of near-term federal regulation, a few states3 have begun to set their own air guidelines for specific PFAS compounds.

Potential PFAS Air Emission Regulations

Future PFAS air regulations could materialize in several ways. If, in its research, the EPA finds that a specific PFAS compound “contributes significantly to air pollution which may reasonably be anticipated to endanger public health,” the EPA could list the category of sources from which PFAS compounds are emitted under section 111(b)(1)(A) of the Clean Air Act (“CAA”). This could lead to the creation of performance standards regulations for both new and existing PFAS sources. Alternatively, the EPA could list a PFAS compound as a Hazardous Air Pollutant (“HAP”) under CAA section 112(b)(2) if it finds that the compound provides a “threat of adverse human health effects” or other “adverse environmental effects.” A HAP designation would be the first step in defining a PFAS category of sources under CAA section 112(c)(5) and could eventually subject those sources to HAP control requirements.

Recently introduced House legislation, the PFAS Action Act of 2021, proposes to require the EPA to list two of the more understood PFAS compounds, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), as HAPs under the CAA. The bill also instructs the EPA to consider designating other PFAS compounds as HAPs over the next five years. A similar bill was passed by the House in 2019 but gained little traction the Senate.

In order to make the requisite findings underpinning potential regulations and develop enforceable standards, the EPA will need to overcome several obstacles related to the movement and impact of PFAS chemicals in the environment.

PFAS Air Emission Regulation Obstacles and Complexity

One of the most significant obstacles for federal regulation of PFAS air emissions is the lack of standardized methods for measuring PFAS air emissions. EPA has provided a tracker for its efforts to, among other things, develop methods to detect and quantify PFAS in air, water, and soil.4 One independent method for measuring PFAS emissions from stationary sources, OTM-45, has been found by the EPA to be “potentially useful,” but this method has not been subject to federal rulemaking procedures, and at this time, the EPA is still soliciting feedback on the methodology.5 The EPA is currently not expected to begin evaluating its own proposed candidate methods for measuring PFAS emissions from stationary sources until 2022.6 EPA research on measuring atmospheric deposition of PFAS onto surface water and earth is in even earlier stages.7

Another obstacle is the lack of toxicity studies on the health risks for nearly all airborne PFAS compounds. PFAS refers to a wide variety of chemicals, which differ from one another in many ways that could be significant to environmental regulation. Most of the limited research thus far has focused on the health impacts via ingestion of a few select PFAS compounds. The EPA will need to understand the relative inhalation risks and impacts of each specific PFAS substance to form the basis for any national air emission regulation for that PFAS compound. The EPA is currently working on toxicity assessments for seven of the most common PFAS.8

Adding another layer of complexity to air regulations of PFAS compounds are the variety of emission sources. PFAS have been found to enter air through stack emissions at industrial facilities, waste treatment plants, and indoor and outdoor uses of PFAS-containing products (e.g., firefighting foam). Additionally, some of the more volatile PFAS substances can migrate from water and soil sources into the air.


While water and soil contamination remains the primary focus of federal PFAS regulatory efforts, the EPA has also committed itself to improving the scientific understanding the environmental and health impacts of PFAS air emissions. In the latest update to its PFAS action plan, released in February 2020, the EPA stated it was “working to better characterize and understand the environmental impacts of PFAS emitted to the air.” As testing methods are identified, toxicology studies are completed, and transport models tuned, the agency may consider rules regulating air emissions of PFAS. But at this time, the agency has not begun any rulemaking efforts to that effect.

Businesses that deal in PFAS-containing products or engage in industrial processes that include PFAS substances should keep an eye out for updates to the EPA’s PFAS Action Plan and news releases from the EPA Council on PFAS. When released, the council’s “PFAS 2021-2025 – Safeguarding America’s Water, Air and Land” strategy should provide clearer guidance for whether and when air emission regulations might be promulgated for select PFAS compounds. Businesses should also remain mindful of potential legislative action at both the state and federal level, as well as potential state regulations that may move faster than the EPA process.

1 Press Release, EPA, EPA Administrator Regan Establishes New Council on PFAS (Apr. 27, 2021), available at:

2 Jason E. Galloway, et al., Evidence of Air Dispersion: HFPO-DA and PFOA in Ohio and West Virginia Surface Water and Soil near a Fluoropolymer Production Facility, 54 Envtl. Sci. & Tech. 7175 (2020), available at

3 Michigan and New Hampshire have set regulatory thresholds for some PFAS compounds. Texas has set an advisory ambient air threshold. New York and California’s respective environmental agencies are considering setting regulatory thresholds.

4 Status of EPA Research and Development on PFAS, (Apr. 20, 2021), available at:

5 Id.

6 Id.

7 Id.

8 Targeted PFAS include: Perfluorononanoate (PFNA), Perfluorobutyrate (PFBA), Perfluorohexanoic acid (PFHxA), Perfluorohexane Sulfonic Acid (PFHxS), Perfluorodecanoate (PFDA), Perfluorobutane Sulfonic Acid (PFBS), and Hexafluoropropylene Oxide (HFPO) Dimer Acid and its related salts (known as GenX Chemicals).

This information is provided by Vinson & Elkins LLP for educational and informational purposes only and is not intended, nor should it be construed, as legal advice.