On May 18, 2026, the U.S. Environmental Protection Agency (EPA) announced it would repeal federal drinking water limits on four PFAS “forever chemicals” — GenX, PFNA, PFBS, and PFHxS — while simultaneously proposing to allow water utilities an additional two years (until 2031) to comply with existing standards for PFOA and PFOS, the most notorious and well-studied of these compounds.[1] In a single announcement, protections that took decades of science and advocacy to establish were placed on the chopping block.
For BCPP, this is not an abstraction. This is the world we have been working to change.
What Was Just Rolled Back — and Why It Matters
The 2024 drinking water standards that the EPA is now dismantling were historic. They represented the first time in 30 years that the agency had set enforceable limits for a new drinking water contaminant. Together, those rules had the potential to protect up to 105 million people whose water providers had detected PFAS above safe levels.[2]
Now those protections are being repealed for four of the six regulated chemicals — and delayed for the remaining two. The EPA framed this as a correction of procedural errors from the prior administration.[1] But the science telling us these chemicals are dangerous did not change on May 18th. What changed was the political will to act on it.
PFAS Forever Chemicals, Lasting Harm
PFAS — per- and polyfluoroalkyl substances — are a family of nearly 15,000 manufactured chemicals used in nonstick cookware, water-resistant clothing, food packaging, stain-resistant furniture, and firefighting foam. They are called “forever chemicals” because they resist environmental degradation, accumulating in ecosystems and in human bodies for years or decades.[3]
A 2023 study by the U.S. Geological Survey estimated that at least 45% of the nation’s tap water contains one or more types of PFAS.[4] Biomonitoring data from NHANES surveys indicate that at least one PFAS was detected in more than 99% of samples from a nationally representative population cohort.[5] These chemicals don’t just pass through us. They persist. They have been detected in umbilical cord blood and placental tissue, indicating that fetal exposure begins in utero, before a child ever takes a first breath.[6]
The documented health consequences of PFAS exposure are broad and serious. The Agency for Toxic Substances and Disease Registry (ATSDR) and the National Academies of Sciences, Engineering, and Medicine (NASEM) have reviewed the evidence and identified associations with liver disease, thyroid disruption, lipid dysregulation, reduced kidney function, impaired immune function — including reduced vaccine response in children — adverse reproductive and developmental outcomes, and cancer.[7][8]
In 2023, an IARC Working Group of 30 scientists from 11 countries reviewed the evidence and classified PFOA as a Group 1 human carcinogen — based on sufficient animal evidence, strong mechanistic evidence in humans, and limited epidemiological evidence for renal cell carcinoma and testicular cancer — and PFOS as a Group 2B possible human carcinogen, based primarily on strong mechanistic evidence.[9] These are not contested fringe findings. They are the consensus of the world’s leading cancer research body.
The Breast Cancer Prevention Lens
At BCPP, we view this rollback through one clear lens: what are the implications for preventing breast cancer?
The answer is deeply concerning — and the science is evolving rapidly.
PFAS are hypothesized to increase breast cancer risk through multiple biological mechanisms. Research shows that certain PFAS can bind to and activate peroxisome proliferator-activated receptor (PPAR)-α/γ signaling pathways, increasing hepatic aromatase activity and downstream estrogen levels — a mechanism directly relevant to hormone-driven breast cancer.[10] PFAS have also been shown to interfere with hormone receptors and exert weak xenoestrogen effects, meaning they can mimic or disrupt the body’s own estrogen signaling.[11] Additionally, PFOA has been found to induce epigenetic alterations and act as an immunosuppressant — both pathways with potential implications for cancer development.[9]
Epidemiological findings on PFAS and breast cancer risk are an active area of scientific investigation, with mixed results across studies. A 2022 meta-analysis found that PFOA and PFHxS were positively associated with breast cancer risk, with pooled odds ratios of 1.32 (95% CI: 1.19–1.46) and 1.79 (95% CI: 1.51–2.11), respectively.[12] A 2024 systematic review and meta-analysis published in the American Journal of Epidemiology — drawing on 18 studies — found that while overall PFAS-breast cancer associations were not statistically significant in pooled analyses, a positive association with PFOA emerged when analyses were limited to studies assessing exposure before breast cancer diagnosis (RR = 1.16 for a log-unit increase in serum concentration).[13] A Chinese case-control study found PFOA positively associated with estrogen receptor-positive, progesterone receptor-positive, and HER2-positive breast cancers.[14] A further 2024 systematic review and meta-analysis found evidence linking PFAS exposure to ovarian cancer (RR = 1.07; 95% CI: 1.04–1.09) and identified possible effects on breast cancer incidence in specific subgroups.[15]
The science is not settled — but the weight of evidence points in a troubling direction, particularly for premenopausal women and those with hormone-positive tumors. As BCPP’s 2025 State of the Evidence database makes clear, drawing on nearly 1,750 peer-reviewed studies, PFAS stands among the high-priority endocrine-disrupting compounds most urgently implicated in breast cancer etiology.[16]
The precautionary principle — the foundational idea that we should not wait for perfect proof before protecting people from foreseeable harm — demands that we act on this evidence now. Not after the case is closed.
Regulation Is Prevention
It is tempting to think of environmental regulation as a separate domain from health — as if protecting water quality were an issue for engineers and policy wonks, not doctors, patients, and the 1 in 8 women who will be diagnosed with breast cancer in their lifetime.
But regulation is prevention. When a water utility is required to filter PFAS out of drinking water, that is primary prevention. When a chemical is removed from food packaging before it leaches into a meal, that is primary prevention. When a cosmetic brand is prohibited from adding PFAS to its products, that is primary prevention.
The strongest lever we have against breast cancer — and against PFAS-related disease broadly — is not a pill or a screening. It is eliminating exposure before it happens.
That’s why the EPA’s rollback is not just a setback for environmental policy. It is a setback for cancer prevention. It is a setback for reproductive health. It is a setback for every community — disproportionately low-income, disproportionately communities of color — that lives downstream from contamination and lacks resources to filter their own water.
What Comes Next: Prevention Cannot Wait for Policy
We are not naive about the landscape we’re operating in. Federal protections are fragile. But PFAS in drinking water is not a partisan issue — it is a public health crisis that was decades in the making, and it will require sustained pressure to resolve.
The science is not in dispute. PFOA is a human carcinogen. PFOS is a possible human carcinogen.[9] Tens of millions of Americans are drinking water contaminated with these chemicals above levels the EPA itself identified as harmful.
State-level protections matter more than ever. BCPP has co-sponsored landmark California laws banning PFAS in cosmetics and clothing. These victories stand regardless of federal retreat, and we will continue to press for state-level standards that protect people where federal protections fail.
Corporate accountability remains powerful. We have successfully pressured REI, Restaurant Brands International, and other companies to eliminate PFAS from their products and packaging. Companies respond to organized consumer advocacy — especially when regulation creates a vacuum.
Individual exposure reduction is real, if limited. There are steps people can take today: choosing PFAS-free cookware and food packaging, filtering drinking water with NSF/ANSI Standard 58 certified reverse osmosis systems or Standard 53 activated carbon filters, and avoiding stain-resistant treatments on furniture and clothing. These steps matter — but they are not a substitute for the systemic protections that government has an obligation to provide.
A Call to Action
The EPA’s proposed rules are open for public comment, and your voice matters. There are two ways to make it heard:
Submit written comments by July 20, 2026:
- To comment on the rescission of GenX, PFNA, PFHxS, and PFBS limits: go to regulations.gov and search Docket ID EPA-HQ-OW-2025-0654
- To comment on the PFOA/PFOS compliance deadline extension: go to regulations.gov and search Docket ID EPA-HQ-OW-2025-1742
Attend or speak at the virtual public hearing on July 7, 2026. Pre-registration to provide verbal comments is required by July 1, 2026. Register at EPA’s proposed rescission rule page or contact PFASNPDWR@epa.gov.
Tell federal regulators that weakening PFAS standards is unacceptable, that 105 million people deserve clean drinking water, and that a government committed to public health cannot simultaneously classify PFOA as a human carcinogen and walk away from the rules designed to limit exposure to it.
Support the organizations — including BCPP — fighting every day to prevent breast cancer before it starts, in the lab, in the legislature, and in the marketplace.
We cannot change our genes. But we can change our environment.
Breast Cancer Prevention Partners (BCPP) is the leading science-based policy and advocacy organization working to prevent breast cancer by eliminating our exposure to toxic chemicals and radiation. Learn more and take action at bcpp.org.
References
[1] U.S. Environmental Protection Agency. “Per- and Polyfluoroalkyl Substances (PFAS).” EPA, May 18, 2026. https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas.
[2] Earthjustice. “Trump EPA Proposes to Eliminate and Delay Protections from Toxic Forever Chemicals in Drinking Water.” Press release, May 18, 2026. https://earthjustice.org/press/2026/trump-epa-proposes-to-eliminate-and-delay-protections-from-toxic-forever-chemicals-in-drinking-water.
[3] Evich, Marina G., Mary J.B. Davis, James P. McCord, Bowman Acrey, Jacob A. Awkerman, David R.U. Knappe, Andrew B. Lindstrom, et al. “Per- and Polyfluoroalkyl Substances in the Environment.” Science 375, no. 6580 (2022): eabg9065. https://doi.org/10.1126/science.abg9065.
[4] Smalling, Kelly L., Tammy M. Romanok, Paul M. Bradley, Michael J. Focazio, James L. Gray, Sara E. Breitmeyer, Daniel K. Jones, et al. “Per- and Polyfluoroalkyl Substances (PFAS) in United States Tapwater: Comparison of Underserved versus Served Communities and Recommendations for Future Research.” Science of the Total Environment 892 (2023): 164473. https://doi.org/10.1016/j.scitotenv.2023.164473. [See also: USGS National News Release, “Tap Water Study Detects PFAS Forever Chemicals Across US,” July 2023, https://www.usgs.gov/news/national-news-release/tap-water-study-detects-pfas-forever-chemicals-across-us.]
[5] Botelho, Julianne Cook, Kayoko Kato, Lee-Yang Wong, and Antonia M. Calafat. “Per- and Polyfluoroalkyl Substances (PFAS) Exposure in the U.S. Population: NHANES 1999–March 2020.” Environment International 195 (2025): 109246. https://doi.org/10.1016/j.envint.2024.109246.
[6] Muir, Tara, Neil C. Dodder, Nicholas J. Lax, Olusegun J. Olateju, and Erica D. Bruce. “Concentrations of Per- and Polyfluoroalkyl Substances (PFAS) in Human Placental Tissues and Associations with Birth Outcomes.” Environmental Research 207 (2022): 112232. https://doi.org/10.1016/j.envres.2021.112232.
[7] Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Perfluoroalkyls. Atlanta: U.S. Department of Health and Human Services, 2021. https://www.atsdr.cdc.gov/ToxProfiles/tp200.pdf.
[8] National Academies of Sciences, Engineering, and Medicine. Guidance on PFAS Exposure, Testing, and Clinical Follow-Up. Washington, DC: The National Academies Press, 2022. https://doi.org/10.17226/26156.
[9] Zahm, Shelia, Jens Peter Bonde, Weihsueh A. Chiu, Jane Hoppin, Jun Kanno, Mounia Abdallah, and 24 others. “Carcinogenicity of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS).” The Lancet Oncology 25, no. 1 (2024): 16–17. https://doi.org/10.1016/S1470-2045(23)00622-8.
[10] DeWitt, Jamie C., Courtney B. Peden-Adams, Judith E. Keller, and Dori R. Germolec. “Immunotoxicity of Perfluorinated Compounds: Recent Developments.” Toxicologic Pathology 40, no. 2 (2012): 300–311. [See also for PPAR mechanism: Ripon, Rezaul Karim, Md Jamil Hossain, Mayra Volquez, et al. “PFAS Exposure and Endocrine Disruption Among Women.” JAMA Network Open 8, no. 12 (2025): e2539425. https://doi.org/10.1001/jamanetworkopen.2025.39425.]
[11] Zhao, Lijing, Liqin Zhu, Zhiqiang Zhang, Wenjun Ma, Wenwen Guo, and Zhiwen Li. “Endocrine Disrupting Chemicals and Breast Cancer: A Systematic Review of Epidemiological Studies.” Critical Reviews in Food Science and Nutrition 62, no. 7 (2022): 1849–1873. https://doi.org/10.1080/10408398.2021.1903382.
[12] Liu, Beiqi, Zhixia Xie, Jiajia Lv, Jingjin Li, Qinmei Sun, and Dong Li. “Associations between Polyfluoroalkyl Substances Exposure and Breast Cancer: A Meta-Analysis.” International Journal of Environmental Research and Public Health 19, no. 12 (2022): 7232. https://doi.org/10.3390/ijerph19127232.
[13] Chang, Che-Jung, Jennifer L. Ish, Vicky C. Chang, Meklit Daniel, Rena R. Jones, and Alexandra J. White. “Exposure to Per- and Polyfluoroalkyl Substances and Breast Cancer Risk: A Systematic Review and Meta-Analysis of Epidemiologic Studies.” American Journal of Epidemiology 193, no. 8 (2024): 1182–1196. https://doi.org/10.1093/aje/kwae010.
[14] Li, Xuejun, Fengju Song, Xiaotu Liu, Anqi Shan, Yubei Huang, Zhengjun Yang, Haixin Li, et al. “Perfluoroalkyl Substances (PFASs) as Risk Factors for Breast Cancer: A Case-Control Study in Chinese Population.” Environmental Health 21, no. 1 (2022): 93. https://doi.org/10.1186/s12940-022-00895-3.
[15] Seyyedsalehi, Monireh Sadat, Elizabeth Maria Kappil, Sirui Zhang, Tongzhang Zheng, and Paolo Boffetta. “Per- and Poly-Fluoroalkyl Substances (PFAS) Exposure and Risk of Breast and Female Genital Cancers: A Systematic Review and Meta-Analysis.” La Medicina del Lavoro 115, no. 6 (2024): e2024043. https://doi.org/10.23749/mdl.v115i6.16330.
[16] Breast Cancer Prevention Partners. “BCPP Overview: Introducing the State of the Evidence Database.” BCPP, February 2026. https://www.bcpp.org/introducing-the-state-of-the-evidence-database/.
