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 However, these have been replaced by thousands of other PFAS compounds.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.
Editor's Note: This is Part One of a two-part series exploring direct exposure to PFAS. Part One explores the origin of PFAS and inhalation effects. Part Two discusses inhalation, dermal exposure, drinking water and additional research.
 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