Per- and Polyfluoroalkyl Substances (PFAS)
Overview
This Contaminant Focus Area summarizes the current understanding of per- and polyfluoroalkyl substances (PFAS) with respect to their historical and current uses, sources, chemistry and analysis, potential human exposure and associated adverse health outcomes, environmental fate and transport, site investigation techniques, and remediation technologies for treatment of environmental media contaminated with PFAS at levels of concern.
PFAS are a diverse class of thousands of fluorinated compounds that have been used extensively in industrial, commercial, and consumer applications. Historically, the most commonly used PFAS have been perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). While the manufacture and import of PFOA was phased out in the U.S. as part of the PFOA Stewardship program (USEPA 2016a) and in 2002, the only major U.S. manufacturer of PFOS voluntarily agreed to phase out its production, PFOS and related compounds continue to be produced in other countries. Exposure to PFOA and PFOS in the U.S. remains possible due to continued use of legacy products containing these compounds, their presence in imported goods, the degradation of precursor compounds, and their extremely high persistence in the environment and the human body.
PFAS are both hydrophobic (water-repelling) and oleophobic/lipophobic (oil/fat-repelling), which makes them beneficial in surface coating and protectant formulations. The carbon-fluorine bonds of the PFAS molecule are very stable and impart high thermal and chemical stability. Therefore, PFAS persist in the environment (Buck et al., 2011) and are found worldwide in environmental media, wildlife, and humans (Houde et al. 2006, 2007, and 2011, Lau et al. 2007, Lindstrom et al. 2011, and USEPA 2016b). PFAS may also impact agriculture through production inputs.
The Interstate Technology Regulatory Council (ITRC) maintains several useful resources related to PFAS, encompassing a comprehensive overview of PFAS, which includes information on historical and current uses of PFAS. ITRC's fact sheets on naming conventions, the history and use of PFAS, and regulations, in addition to other topics, are another resource available to learn more about PFAS.
Applications
Common applications of PFAS have included (OECD 2013 and Buck et al. 2011):
- Protectants that enhance water, grease, and soil repellency of paper and cardboard packaging, carpet, leather products, and textiles.
- Industrial surfactants, emulsifiers, wetting agents, additives, and coatings.
- Aqueous film forming foams (AFFF) for firefighting because they are effective in extinguishing hydrocarbon-fueled fires.
- Processing aids in the manufacture of fluoropolymers, such as nonstick coatings on cookware, membranes for clothing that are both waterproof and breathable, electrical wire casing, fire- and chemical-resistant tubing, and plumbing thread seal tape.
For a more comprehensive list of information on historical and current uses of PFAS see Table 2-6 of ITRC's PFAS -Per- and Polyfluoroalkyl Substances (ITRC, 2023).
Policy and Guidance
Below are some key resources on PFAS. For more information, practitioners are encouraged to consult EPA's PFAS webpage https://www.epa.gov/pfas for updates, as well as State agency websites for state-specific policies and guidance.
- EPA's PFAS Strategic Roadmap lays out an Agency-wide approach to address PFAS. The roadmap sets timelines by which EPA plans to take specific actions and commits to new policies to protect human health and the environment. EPA's strategic roadmap is structured around three overarching goals: restricting PFAS from entering the environment, remediating PFAS contamination, and investing in PFAS research.
- EPA's Final PFAS National Primary Drinking Water Regulation (EPA, 2024) established legally enforceable levels (Maximum Contaminant Levels [MCLs], for six PFAS in drinking water: PFOA, PFOS, perfluorohexane sulfonate (PFHxS), perfluorononanoate (PFNA), and hexafluoropropylene oxide dimer acid (HFPO-DA), as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, and HFPO-DA, and perfluorobutane sulfonate (PFBS) using a Hazard Index MCL to account for combined and co-occurring levels of these PFAS in drinking water.
To learn more about what EPA is doing to address PFAS, go to EPA's Key Actions to Address PFAS webpage.
References:
Buck, R.C. et al. 2011. Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins. Integrated Environmental Assessment & Management 7(4):513-541.
Houde, M. et al. 2006. Biological Monitoring of Polyfluoroalkyl Substances: A Review. Environmental Science & Technology 40(11):3463-3473. (Abstract)
Houde, M. et al. 2011. Monitoring of Perfluorinated Compounds in Aquatic Biota: An Updated Review PFCs in Aquatic Biota. Environmental Science & Technology 45(19):7962-7973. (Abstract)
International Technology & Regulatory Council (ITRC). PFAS Technical and Regulatory Guidance Document and Fact Sheets PFAS-1. 2023. https://pfas-1.itrcweb.org/.
Lau, C., K. Anitole, C. Hodes, D. Lai et al. 2007. Perfluoroalkyl Acids: A Review of Monitoring and Toxicological Findings. Toxicological Sciences 99(2):366-394.
Lindstrom, A.B., M.J. Strynar, and E.L. Libelo. 2011 Polyfluorinated Compounds: Past, Present, and Future. Environmental Science & Technology 45(19):7954-7961.
OECD (Organisation for Economic Co-operation and Development). 2013. 
Synthesis Paper on Per- and Polyfluorinated Chemicals (PFCs). OECD/UNEP Global PFC Group, Environment, Health and Safety, Environment Directorate, 60 pp.
OECD (Organisation for Economic Co-operation and Development). 2018. Toward A New Comprehensive Global Database Of Per-and Polyfluoroalkyl Substances (PFAS): Summary Report On Updating The OECD List of Per-and Polyfluoroalkyl Substances (PFAS). Series on Risk Management No. 39, 24 pp.
USEPA (U.S. Environmental Protection Agency). 2016a Fact Sheet: 2010/2015 PFOA Stewardship Program. EPA website.accessed March 11, 2025.
USEPA (U.S. Environmental Protection Agency). 2016b Per- and Polyfluoroalkyl Substances (PFASs) under TSCA. EPA website.accessed March 11, 2025.
USEPA (U.S. Environmental Protection Agency). 2021. EPA's PFAS Strategic Roadmap: EPA's Commitments to Action 2021-2024. EPA 100-K-21-002, 26 pp.
USEPA (U.S. Environmental Protection Agency). 2024 Final PFAS National Drinking Water Regulation. EPA website, accessed March 25, 2025.
Additional Resources
Government & Other Publicly Available Resources
Developing a Crosswalk Between Legacy Chemical and Per- and Polyfluoroalkyl Substances (PFAS) Sites — RPM Bulletin 2024-02
U.S. EPA, Washington, DC. 2 pp, 2024
Assists RPMs with tracking the location of PFAS with regard to "legacy" contaminants that have been historically addressed in the Superfund program.
Considerations When Reviewing Per- and Poly-fluoroalkyl Substances (PFAS) in Five-Year Reviews — RPM Bulletin 2024-01
U.S. EPA, Washington, DC. 52 pp, 2024
Assists RPMs when reviewing how PFAS are addressed in Federal Facility Superfund Sites' Five-Year Reviews.
Interstate Technology and Regulatory Council (ITRC) PFAS Fact Sheets
Interstate Technology and Regulatory Council (ITRC), 2023
This series of fact sheets provides additional information about PFAS:
EPA PFAS Explained Fact Sheet
U.S. EPA, Washington, DC. 4 pp, 2023
Explains what PFAS are, where they are found, and what actions EPA is taking to address them.
PFAS in Biosolids: A Review of State Efforts & Opportunities for Action
Hughes, S.G., Environmental Council of States, 29 slides, 2023
Summarizes state efforts and opportunities for action regarding PFAS in biosolids, highlighting the need for standardized methods for measuring PFAS.
Technology Assessment: Persistent Chemicals - Technologies for PFAS Assessment, Detection, and Treatment
U.S. Government Accountability Office (GAO), Washington, DC. 57 pp, 2022
Assesses technologies and identifies three policy options that could help mitigate the challenges associated with PFAS assessment, detection, and treatment technologies.
Summary Report: Strategic Workshop on Management of PFAS in the Environment
Strategic Environmental Research and Development Program & Environmental Security Technology Certification Program Report, 90 pp, 2022
Summarizes the research, demonstration, and technology transfer needs identified at a PFAS workshop, which highlighted critical and high-priority areas, such as determining the physical-chemical properties of PFAS and assessing processes impacting PFAS migration.
EPA's Per- and Polyfluoroalkyl Substances (PFAS) Action Plan
U.S. EPA, Washington, DC. EPA 823-R-18-004, 72 pp, 2019
Outlines steps to address PFAS challenges, including characterizing risks and developing monitoring and treatment techniques. The plan was informed by input from stakeholders gathered during the PFAS National Leadership Summit, community engagements, and public comments.
Lists of PFOS, PFAS, PFOA, PFCA Related Compounds and Chemicals That May Degrade to PFCA
OECD (Organisation for Economic Co-operation and Development). Environment, Health and Safety Publications Series on Risk Management No. 21, ENV/JM/MONO(2006)15, 157 pp, 2007
Contains annexed lists of PFOS, PFAS, PFOA, their related chemical substances, and chemicals that may degrade to PFCA based on member country responses to the OECD surveys; OECD member country inventories; reviews by international agencies or regulatory bodies; and published literature.
On Per- And Polyfluoroalkyl Substances: Suggested Resources and Considerations for Groundwater Professionals
Frankel, A.J. | Groundwater 59(4):481-487(2021) [Abstract]
Suggests resources and key considerations for groundwater professionals wishing to familiarize themselves with PFAS compounds. Discusses background information, current groundwater-related regulations, risk considerations, and mitigation options. It also compares PFAS to other groundwater contaminants and provides a broad selection of references.
Perfluorinated Chemicals (PFCs) - Perfluorooctanoic Acid (PFOA) & Perfluorooctane Sulfonate (PFOS) - Information Paper
ASTSWMO (Association of State and Territorial Solid Waste Management Officials), 68 pp, 2015
Contains brief discussions of manufacturing and uses, environmental fate and transport, health and environmental effects, and analytical and treatment methods for PFOA and PFOS.
Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins
Buck, R.C., J. Franklin, U. Berger, J.M. Conder, I.T. Cousins, P. de Voogt, A. Astrup, et al.
Integrated Environmental Assessment & Management 7(4):513-541(2011)
Provides an overview of PFAS and recommends clear, specific, and descriptive terminology, names, and abbreviations for the compounds with particular emphasis on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors.
Potential Designated Chemicals: Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs)
California Environmental Contaminant Biomonitoring Program, 22 pp, 2015.
Summarizes chemical identity and example structures, exposure or potential exposure to the public or specific subgroups, known or suspected health effects, and results of biomonitoring studies of some PFAS subclasses.
Synthesis Paper on Per- and Polyfluorinated Chemicals (PFCs)
OECD/UNEP Global PFC Group, Environment, Health and Safety, Environment Directorate, 60 pp, 2013
Provides overviews of (1) historical and current major uses of PFASs; (2) scientific evidence on sources to the environment, environmental fate, human exposure, and potential adverse effects; (3) recent developments on alternatives to long-chain PFASs; and (4) European regulatory approaches with respect to PFAS.
Webpages with More Information
ITRC PFAS Fact Sheets
Interstate Technology and Regulatory Council (ITRC) Website.
NGWA Groundwater and PFAS
National Ground Water Association (NGWA) Website
NIEHS Environmental Health Topics: PFAS
National Institute of Environmental Health Sciences (NIEHS) Website
FDA Environmental Contaminants in Food: PFAS
U.S. Food and Drug Administration (FDA) Website
EPA Science Inventory
U.S. EPA Website
EPA PFOA, PFOS, and Other PFAS: U.S. State Resources about PFAS
U.S. EPA Website
EPA Safer Chemicals Research: PFAS
U.S. EPA Website
EPA Safer Chemicals Research: PFAS Research Archive
U.S. EPA Website
EPA Final PFAS National Primary Drinking Water Regulation
U.S. EPA Website
DOD PFAS Task Force
Office of the Under Secretary of Defense (OUSD) Website
ATSDR: PFAS and Your Health
Agency for Toxic Substances and Disease Registry (ATSDR) Website
C8 Science Panel
Fletcher, T., D. Savitz, and K. Steenland (2020) Website
AWWA Water Quality Resource Topics: PFAS
American Water Works Association (AWWA) Website
EnviroWiki: PFAS
Deeb, R., J. Field, L. Dorrance, E. Hawley, and C. Higgins, (2024) Website
SERDP & ESTCP PFAS Focus Area Projects
SERDP & ESTCP Website
Research Papers (Open Access)
Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins
Buck, R.C., J. Franklin, U. Berger, J.M. Conder, I.T. Cousins, P. de Voogt, A. Astrup, et al.
Integrated Environmental Assessment & Management 7(4):513-541(2011)
Provides an overview of PFASs detected in the environment, wildlife, and humans and recommends clear, specific, and descriptive terminology, names, and acronyms for PFASs.
Identification and Classification of Commercially Relevant Per- and Poly-fluoroalkyl Substances (PFAS)
Buck, R.C., S.H. Korzeniowski, E. Laganis, and F. Adamsky.
Integrated Environmental Assessment and Management 17(5):1045-1055 (2021)
Identifies the commercially relevant PFAS substances on the 2018 OECD/UNEP Report list based on input from three major global producers. The study identified and classified 256 commercially relevant PFAS, which is a small subset of the 4,730 PFAS substances presented in the 2018 OECD/UNEP Report.
Polyfluorinated Compounds: Past, Present, and Future
Lindstrom, A.B., M.J. Strynar, and E.L. Libelo.
Environmental Science & Technology 45(19):7954-7961 (2011)
Discusses the past, present, and future of polyfluorinated compounds. Studies suggest a number of important potential health effects.
Historical and Current Usage of Per- and Polyfluoroalkyl Substances (PFAS): A Literature Review
Gaines, L.G. American Journal of Industrial Medicine 66(5): 353-378 (2022)
Reviews publicly available sources to summarize information on the wide variety of industrial, commercial, and consumer applications of PFAS since the 1950s. It finds that PFAS are used in a wide variety of applications, summarized into 25 broad industries.
Addressing Urgent Questions for PFAS in the 21st Century
Ng, C., I.T. Cousins, J.C. DeWitt, J. Gluge, G. Goldenman, D. Herzke, R. Lohmann, et al.
Environmental Science & Technology 55(19): 12755-12765 (2021)
Discusses the importance of identifying specific PFAS, their concentrations, and their sources to characterize environmental contamination and exposure pathways. It emphasizes combining occurrence data with PFAS identities and concentrations in products and environmental matrices to develop exposure signatures.
Scientific Basis for Managing PFAS as a Chemical Class
Kwiatkowski, C.F., D.Q. Andrews, L.S. Birnbaum, T.A. Bruton, J.C. DeWitt, et al.
Environmental Science & Technology Letters 7(8): 532-543 (2020)
This article expresses the views of the authors regarding the scientific basis for managing PFAS as a chemical class.
PFAS Exposure Pathways for Humans and Wildlife: A Synthesis of Current Knowledge and Key Gaps in Understanding
De Silva, A.O., J.M. Armitage, T.A. Bruton, C. Dassuncao, W. Heiger-Bernays, et al.
Environmental Toxicology and Chemistry 40(3): 631-657 (2020)
Synthesizes current understanding of PFAS exposure sources for humans and wildlife and identifies key knowledge gaps that inhibit the development of informed regulatory decisions. It reviews PFAS sources and environmental transport pathways, analytical methods, human exposure assessment, and bioaccumulation in wildlife.
An Overview of Per- and Polyfluoroalkyl Substances (PFAS) in the Environment: Source, Fate, Risk and Regulations
Abunada, Z., M.Y. Alazaiza, and M.J. Bashir.
Water 12(12): 3590 (2020)
Reviews the current state of per- and polyfluoroalkyl substances (PFASs), discussing their occurrence, characterization, treatment, and potential human exposure routes. It highlights the complexity of regulating PFAS compounds due to uncertainty and a lack of epidemiological evidence.
An Overview of the Uses of Per- and Polyfluoroalkyl Substances (PFAS)
Gluge, J., Scheringer, M., Cousins, I.T., DeWitt, J.C., Goldenman, G., Herzke, D., et al.
Environmental Science: Processes & Impacts 22(12): 2345-2373 (2020)
Provides a broad overview of the uses of PFAS and associated individual substances, addressing the use categories and functions of PFAS, the specific PFAS used in each category, and the extent of their use in different parts of the world. The study identifies over 200 uses in 64 use categories for more than 1,400 individual PFAS.
A Review of Recent Studies on Toxicity, Sequestration, and Degradation of Per- and Polyfluoroalkyl Substances (PFAS)
Dickman, R.A., and D.S. Aga.
Journal of Hazardous Materials (436): 129120 (2022)
Provides information on legacy and alternative PFAS compounds and their structures. Numerous legacy and alternative PFAS are recognized as equally important substances for environmental monitoring and remediation.
Trends in the Regulation of Per- and Polyfluoroalkyl Substances (PFAS): A Scoping Review
Brennan, N.M., A.T. Evans, M.K. Fritz, S.A. Peak, and H.E. von Holst.
Environmental Research and Public Health 18(20):10900 (2021)
Outside the Safe Operating Space of a New Planetary Boundary for Per- and Polyfluoroalkyl Substances (PFAS)
Cousins, I.T., J.H. Johansson, M.E. Salter, B. Sha, and M. Scheringer.
Environmental Science & Technology 56(16):11172-11179 (2022)
Additional Research Articles
On Per- And Polyfluoroalkyl Substances: Suggested Resources and Considerations for Groundwater Professionals
Frankel, A.J. | Groundwater 59(4):481-487(2021)
Environmental Fate and Effects of Poly and Perfluoroalkyl Substances (PFAS)
Pancras, T., G. Schrauwen, T. Held, K. Baker, I. Ross, and H. Slenders. | Concawe, Report No. 8/16, 121 pp, 2016
Recent Advances in the Analysis of Per- and Polyfluoroalkyl Substances (PFAS) - A Review
Al Amin, M., Z. Sobhani, Y. Liu, R. Dharmaraja, S. Chadalavada, R. Naidu, et al. | Environmental Technology & Innovation 19:100879 (2020)
Per and Poly-Fluoroalkyl Substances (PFAS) as a Contaminant of Emerging Concern in Surface Water: A Transboundary Review of their Occurrences and Toxicity Effects
Podder, A., A.H. Sadmani, D. Reinhart, N. Chang, and R. Goel. | Journal of Hazardous Materials 419:126361 (2021)