Per- and polyfluoroalkyl substances (PFAS) are a group of human-made chemicals that have infiltrated nearly every aspect of modern life, from nonstick pans to water-repellent clothing, firefighting foams, and food packaging. Their unique properties, such as resistance to heat, water, and oil, have made them desirable in various industries, however, PFAS are not without controversy. As “forever chemicals,” their persistence in the environment and adverse health effects have raised concerns among scientists, policymakers, and communities worldwide.
The advent of PFAS began in the 1930s when chemists at 3M developed the first PFAS chemical, perfluorooctanesulfonic acid (PFOS). Not long after, in the 1940s, DuPont scientists invented another form, perfluorooctanoic acid (PFOA), as part of their development of Teflon, a non-stick coating for pots and pans. These two chemicals, PFOS and PFOA, are the most well-known and widely studied of the PFAS family.
For decades, the advantageous properties of PFAS – resistance to heat, water, and oil – made them highly valued in a variety of industrial and consumer applications. However, it wasn’t until the late 1990s and early 2000s that the potential environmental and health risks associated with these chemicals started to surface. Studies revealed that PFAS are not only incredibly persistent in the environment, but exposures at significant concentrations have adverse effects on human health. This led to a voluntary cessation of PFOA and PFOS use by U.S. manufacturers. However, these have been replaced by thousands of other PFAS compounds. Nonetheless, the environmental and health concerns have created a significant shift in the narrative around PFAS, sparking what has become an ongoing and complex discussion about regulation, remediation, and the future of these ubiquitous substances.
In April 2023, the Environmental Protection Agency (EPA) took its first enforcement action to reduce PFAS in drinking water, using the 2022 Clean Water Act as its basis. While this seems like an obvious step in minimizing consumer encounters with the forever chemicals, in fact, humans are likely to experience significant direct exposure from sources other than drinking water. Primary means of direct exposure have been documented by multiple research groups, including a paper by Harvard University, which are summarized below.
Why does the cheese from a fast-food burger or pizza not stick to its packaging? It’s likely the result of PFAS chemicals. This also includes microwave popcorn bags, candy wrappers, and even some pet food containers. PFAS in this food packaging can leach into the food it contains, causing dietary exposure to the chemicals. The Food and Drug Administration (FDA) is increasingly aware of this possibility, but like the EPA, has not banned the use of these chemicals in food packaging. Non-stick coatings in cookware still commonly contain PFAS and are considered an “authorized use” by the FDA despite continued research into its potential risks. However, researchers have established a systematic review protocol to assess these risks to provide EPA and product manufacturers with the most current and accurate data.
Just as the FDA has yet to ban PFAS use in cookware, they’ve also taken no action to limit its use in cosmetics products. Manufacturers aren’t required to have cosmetic ingredients evaluated for PFAS before hitting the market. FDA is aware of their presence and cites a 2018 study by the Danish EPA on their website denoting the dangers and current research trends. To date, this study is the only risk assessment that has evaluated PFAS in cosmetics. Results found the highest PFAS content in sunscreens, followed by foundations and concealers. Levels of contamination in samples were not enough to be concerning in any single product for one use, but of course, that’s not how cosmetics work. The concern is that consumers are often layering these products daily. For instance, if one applied foundation, concealer, and a sun-repellant moisturizer each morning, the exposure is essentially tripled. Applied day after day, this repeated dermal transmission could have serious effects.
The FDA implemented a reporting system for “manufacturers, packers, and distributors of cosmetic products that are in commercial distribution in the United States,” but the reporting is entirely voluntary. So far, the program has shown a decline in PFAS usage in the limited products reported, but considerably more data and research are needed to adequately assess PFAS usage and consumer risk in all five of these contamination categories and beyond.
Studies have shown that PFAS can also be present in carpet fibers and household dust from those fibers. This presence is concerning because it can result in long-term exposure to these chemicals which can accumulate in the body over time. Babies and children are at a higher risk for this exposure given the extended periods of time they often spend on the floor.
Though included as a potential means of exposure, to date, PFAS exposure through the skin appears to represent a low risk relative to ingestion or inhalation. Many fabrics use forever chemicals on clothing, pillows, blankets, and carpeting – mentioned earlier. The chemicals are used in spray starches, stain-resistant coatings, and Gore-Tex. While these may make many consumer textiles harder to stain or ruin, they do not break down once textiles are discarded. The Environmental Research & Education Foundation (EREF) is currently funding research into textile-to-textile recycling, which could lead to new textile production streams and additional new treatments.
Finally, it is possible to consume PFAS in drinking water. Treatment processes have been studied and implemented to reduce levels of PFAS in drinking water, and as mentioned earlier, EPA took action to regulate levels in March of this year. However, those regulations do little to remove PFAS from the product stream altogether. The EPA’s potential inclusion of PFAS in the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) currently includes passive receivers (entities that neither produce nor manufacture PFAS but receive them through the waste stream) rather than the producers and manufacturers who are introducing the chemicals upstream. Thus far, much of the policymaking around PFAS has focused on managing PFAS concentrations at “end of pipe” rather than preventing them from entering the systems initially. However, in most cases any PFAS existing in end of pipe systems, like wastewater treatment plants or landfill leachate treatment systems, undergo multiple steps of treatment and dilution which represents multiple degrees of separation between a point of contact and human exposure. This is in stark contrast to the other methods of exposure where PFAS directly applied to consumer products is being ingested or inhaled.
Forever chemicals have been in the consumer product stream for almost a century, and their health impacts have largely centered around the 2 ‘legacy’ PFAS compounds: PFOA and PFOS. Most of this research has been conducted at high concentrations in animal studies. The demonstrated human health impacts similarly occurred under high concentration exposure conditions during PFAS manufacturing processes or with almost pure PFAS chemical products, such as anti-firefighting foam.
But what about the vast majority of society that doesn’t work in the PFAS manufacturing or fire-fighting sectors? The research behind exposure risk at lower “environmentally relevant” concentrations is still relatively immature with some studies suggesting impacts at lower concentrations could be benign. However, such research is not conclusive, and more is needed. This, coupled with the fact that PFAS usage is dynamic and compounds being used are fluctuating substantially, makes answering this question both challenging and one that will take a much longer time frame.
 E.M. Sunderland, X.C. Hu, C. Dassuncao, C.C. Wagner, A.K. Tokranov, J.G. Allen. 2019. A review of the pathways of human exposure to poly- and perfluoroalkyl substances (PFASs) and present understanding of health effects. Journal of Exposure Science and Environmental Epidemiology. 29, 131–147, https://doi.org/10.1038/s41370-018-0094-1
 Nicole M. DeLuca, Michelle Angrish, Amina Wilkins, Kris Thayer, Elaine A. Cohen Hubal,
Human exposure pathways to poly- and perfluoroalkyl substances (PFAS) from indoor media: A systematic review protocol, Environment International, Volume 146, 2021, 106308, ISSN 0160-4120, https://doi.org/10.1016/j.envint.2020.106308
 Jinjin Chen, Linbin Tang, Wei-Qiang Chen, Graham F. Peaslee, and Daqian Jiang, Flows, Stock, and Emissions of Poly- and Perfluoroalkyl Substances in California Carpet in 2000–2030 under Different Scenarios, Environmental Science & Technology 2020 54 (11), 6908-6918, DOI: 10.1021/acs.est.9b06956
 Georgia M. Sinclair, Sara M. Long, Oliver A.H. Jones, What are the effects of PFAS exposure at environmentally relevant concentrations? Chemosphere, Volume 258, 2020, 127340, ISSN 0045-6535, https://doi.org/10.1016/j.chemosphere.2020.127340.