Per- and polyfluoroalkyl substances (PFAS)
Photo: Port of Seattle Fire Department
PFAS is often a component of Aqueous Film Forming Foam (AFFF), a class B firefighting foam used for suppression of liquid fuel fires.
- U.S. workers in certain industries, such as chemical manufacturing and firefighting, may be more exposed to PFAS than the general public.
- PFAS exposure has been linked to cancer and other health effects.
- NIOSH has several studies on occupational PFAS exposures and health effects.
Per- and polyfluoroalkyl substances (PFAS) are a group of over 9,000 synthetic chemicals1 that have been used in industry and consumer products, worldwide, for over 70 years. This includes compounds such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and Hexafluoropropylene Oxide Dimer Acid (also known as “GenX”).2 PFAS are used in many different industry and consumer products, including stain-resistant textiles, food-handling materials, firefighting foam, medical devices, paints, personal care products, construction materials, and industrial processing aids. Research suggests exposure to some PFAS might result in harmful health outcomes, including cancer, increased cholesterol levels, and immune system effects.3
Community exposure to PFAS may occur through drinking water, air, soil, food, or consumer products. Workers might be exposed to PFAS in ways that are different than the general public, such as by touching concentrated products or breathing PFAS in the air at their workplace. Some workers may have higher exposures to PFAS than other groups. A person’s industry, occupation, and work activities can impact the specific PFAS they are exposed to, how much they are exposed to, and how they are exposed. Some occupations that are known to be exposed more than the general U.S. population are:
- Chemical manufacturing workers4,5
- Firefighters 6,7
- Ski wax technicians8,9
The American Conference for Governmental Industrial Hygienists (ACGIH) has established Threshold Limit Values (TLVs) for three PFAS in air: perfluoroisobutylene (PFIB), perfluorobutyl ethylene, and ammonium perfluorooctanoate (APFO)—a salt of PFOA. ACGIH® is a professional, not-for-profit scientific association that reviews existing published, peer-reviewed scientific literature and publishes recommendations for safe levels of substances in air based on an 8-hour workday and 40-hour workweek. These recommendations are called TLVs® [ACGIH 2018]. ACGIH TLVs are not standards; they are health-based guidelines derived from scientific and toxicological information.
As early as 2004, NIOSH began research on PFAS. Early studies included laboratory assessments of dermal PFOA absorption and immune function. However, recent research has expanded to include toxicological studies of immune response and evaluation of exposure and health in workers.
The types and uses of PFAS have changed over the past few decades.4 Researchers at NIOSH are leading, supporting, and collaborating with other government and academic researchers to assess exposures to PFAS currently in use as well as the associated routes of exposure and potential health impacts. Studies of those with higher exposures can help improve the understanding of how exposures occur, effective interventions, and the potential impact of PFAS on human health. To support these activities, NIOSH researchers are also developing analytical methods for the measurement of PFAS exposures in the workplace. Research activities include:
- Worker exposure and health assessments in manufacturing workers, service sector workers, and firefighters
- Dermal absorption assessments, sampling and analytical methods, toxicity testing in animals, and high throughput screening in vitro studies
- Firefighter turnout gear testing for PFAS in textiles
- Agency on Toxic Substances and Disease Registry (ATSDR): PFAS and Your Health
- ATSDR: Toxic Substances Portal – Perfluoroalkyls
- US Environmental Protection Agency (EPA): PFOS, PFOA, and other PFASs
- International Agency for Research on Cancer (IARC): Perfluorooctanoic Acid
- Interstate Technology and Regulatory Council (ITRC): PFAS
- Michigan PFAS Action Response Team (MPART): Firefighting Foams
- C8 Science Panel
- National Toxicology Program (NTP): Per- and Polyfluoroalkyl Substances
- NIST: Measurement Science of Per- and Polyfluorinated Alkylated Substances (PFAS)
- Selected Publications with NIOSH Affiliations
1 U.S. Environmental Protection Agency. Comptox Chemicals Dashboard: Master List of PFAS Substances (Version2). Accessed March 11, 2021. https://comptox.epa.gov/dashboard/chemical_lists/pfasmaster
2 United States Environmental Protection Agency. Basic information on PFAS. https://www.epa.gov/pfas/basic-information-pfas
3 Agency for Toxic Substances and Disease Registry. . Toxicological profile for perfluoroalkyls. US Department of Health and Human Services. doi:10.15620/cdc:59198
4 Heydebreck F, Tang, J, Xie Z, Ebinghaus R . Emissions of per- and polyfluoroalkyl substances in a textile manufacturing plant in China and their relevance for workers’ exposure. Environ Sci Technol, 50(19), 10386-10396. doi:10.1021/acs.est.6b03213
5 Olsen GW, Zobel LR . Assessment of lipid, hepatic, and thyroid parameters with serum perfluorooctanoate (PFOA) concentrations in fluorochemical production workers. International Archives of Occupational & Environmental Health, 81(2), 231-246.
6 Rotander A, Toms LM, Aylward L, Kay M, Mueller JF . Elevated levels of PFOS and PFHxS in firefighters exposed to aqueous film forming foam (AFFF). Environ Int, 82, 28-34. doi:10.1016/j.envint.2015.05.005.
7 Leary DB, Takazawa M, Kannan K, Khalil N . Perfluoroalkyl substances and metabolic syndrome in firefighters: A pilot study. J Occup Environ Med, 62(1), 52-57. doi:10.1097/JOM.0000000000001756.
8 Freberg BI, Haug LS, Olsen R, Daae HL, Hersson M, Thomsen C, . . . Ellingsen DG . Occupational exposure to airborne perfluorinated compounds during professional ski waxing. Environ Sci Technol, 44(19), 7723-7728. doi:10.1021/es102033k
9 Nilsson H, Karrman A, Rotander A, van Bavel B, Lindstrom G, Westberg H . Professional ski waxers’ exposure to PFAS and aerosol concentrations in gas phase and different particle size fractions. Environ Sci Process Impacts, 15(4), 814-822. doi:10.1039/c3em30739e