PFAS are a family of more than 12,000 synthetic “forever chemicals,” and PFOA and PFOS are the two most studied members, now linked to cancers and other serious illnesses, targeted by billions of dollars in settlements against 3M, DuPont, and others, and governed by a first-ever federal drinking water standard that is already being partially rolled back. This guide walks through the health risks of PFAS and PFOA, the lawsuits that have reshaped the chemical industry, and the regulations that determine what comes out of your tap.
What PFAS and PFOA Are
PFAS stands for per- and polyfluoroalkyl substances, a category of more than 12,000 compounds that share a chain of carbon and fluorine atoms bonded together. That bond makes them extraordinarily resistant to heat, water, grease, and natural breakdown, which is why they ended up in nonstick cookware, water-repellent fabrics, food packaging, and the aqueous film-forming foam (AFFF) used to put out fuel fires at airports and military bases. The same durability means they persist in soil, water, and the human body for years or decades.1EPA. Risk Management and Per- and Polyfluoroalkyl Substances (PFAS)
PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid) are “long-chain” PFAS built on eight carbon atoms. They were the workhorses of the family for decades. 3M made PFOS for Scotchgard and firefighting foam; DuPont used PFOA to produce Teflon and other fluoropolymers. 3M stopped making PFOS between 2000 and 2002, and eight major manufacturers committed under a 2006 EPA stewardship program to eliminate PFOA emissions and product content by 2015, a goal the agency says all participants met.1EPA. Risk Management and Per- and Polyfluoroalkyl Substances (PFAS) Because the chemicals do not degrade, though, contamination from decades of use remains in groundwater and drinking water systems nationwide.
The Health Risks
In 2023, the International Agency for Research on Cancer classified PFOA as a confirmed human carcinogen and PFOS as a possible human carcinogen. Epidemiological studies have linked PFOA exposure to kidney cancer and PFOS exposure to testicular cancer in studies of U.S. Air Force servicemen.2National Cancer Institute. PFAS
The EPA’s summary of peer-reviewed research also ties PFAS exposure to increased risk of prostate cancer, decreased fertility, high blood pressure in pregnant women, reduced immune response to vaccines, developmental effects in children including low birth weight and accelerated puberty, interference with natural hormones, and higher cholesterol.3EPA. Our Current Understanding of the Human Health and Environmental Risks of PFAS The Agency for Toxic Substances and Disease Registry has specifically linked PFOA to kidney and testicular cancer, pregnancy-induced hypertension and preeclampsia, increased cholesterol, changes in liver enzymes, and small decreases in birth weight, with PFOS sharing several of those associations. ATSDR notes that inconsistent findings and study design limitations mean the full picture is still incomplete.4ATSDR. PFAS Health Effects
A 2022 report by the National Academies of Sciences, Engineering, and Medicine gave clinicians a tiered framework based on combined blood levels of nine PFAS compounds. Below 2 nanograms per milliliter, adverse effects are not expected. Between 2 and 20 ng/mL, there is potential for adverse effects, and clinicians should prioritize standard screenings for conditions like high cholesterol and hypertensive disorders of pregnancy. At or above 20 ng/mL, additional screening for thyroid function, ulcerative colitis, and testicular and kidney cancer is recommended.5Maine DHHS. PFAS Clinician Guidance
CDC data from the National Health and Nutrition Examination Survey show PFAS remain detectable in more than 96% of the U.S. population, though blood levels of PFOS have fallen by more than 85% and PFOA by more than 70% since 1999–2000 as production was curtailed.6ATSDR. PFAS Facts and Stats
How Widespread the Contamination Is
A 2023 U.S. Geological Survey study of 716 tap water locations estimated that at least 45% of U.S. tap water contains one or more PFAS compounds. Concentrations were similar between regulated public water supplies and private wells. Urban areas had roughly a 75% chance of PFAS detection, compared with about 25% in rural areas. The most contaminated regions included the Great Plains, Great Lakes, Eastern Seaboard, and Central and Southern California.7USGS. Tap Water Study Detects PFAS Forever Chemicals Across US
The main contamination sources are firefighting foam used at military bases, airports, and fire training facilities; manufacturing and industrial sites in chrome plating, electronics, and textile or paper production; landfills and hazardous waste sites; and biosolids from wastewater treatment plants spread as agricultural fertilizer.3EPA. Our Current Understanding of the Human Health and Environmental Risks of PFAS A Government Accountability Office survey of public water systems across six states found 77% had not yet fully implemented a PFAS treatment method, and many managers reported they did not know how PFAS was entering their water.8GAO. PFAS Forever Chemicals May Be Biggest Water Problem Since Lead
The Department of Defense has identified more than 700 U.S. military sites known or suspected to have discharged PFAS, largely from AFFF use since the 1970s.9Disabled American Veterans. PFAS Contaminated Water on Military Bases Research at Joint Base Cape Cod found contamination persists on “centurial” timescales and that groundwater concentrations can exceed regulatory limits by a factor of 2,000 decades after foam use stopped, in part because precursor chemicals slowly transform into PFOS in the soil.10National Library of Medicine. PFAS Contamination From AFFF at Fire Training Sites As of September 2025, DoD had completed assessments or inspections at 704 of 723 identified installations and found off-base drinking water contamination above 70 parts per trillion of PFOS or PFOA at 55 of them.11Department of Defense. Cleanup PFAS
The Federal Drinking Water Rule and the 2025–2026 Rollback
On April 10, 2024, the EPA finalized the first-ever National Primary Drinking Water Regulation for PFAS. The rule set a maximum contaminant level of 4.0 parts per trillion each for PFOA and PFOS, with maximum contaminant level goals of zero, reflecting the agency’s conclusion that no level of exposure to these two compounds is safe. Four other compounds — PFHxS, PFNA, HFPO-DA (GenX), and a hazard index for mixtures of those three plus PFBS — received MCLs of 10 parts per trillion (or a hazard index value of 1 for mixtures).12EPA. Per- and Polyfluoroalkyl Substances (PFAS)
Public water systems were originally required to complete initial monitoring by 2027 and install treatment by 2029 if levels exceeded the MCLs. The EPA estimated annual compliance cost at roughly $1.55 billion, with 4,100 to 6,700 systems serving 83 to 105 million people needing to add treatment.13EPA. PFAS NPDWR Fact Sheet: Cost and Benefits The American Water Works Association put the figure much higher in an August 2024 analysis: $37 to $48 billion in capital improvements over five years and $2.7 to $3.5 billion annually including operations and maintenance.14Association of State Drinking Water Administrators. AWWA Releases Updated National PFAS Cost Estimate
The rule did not stay fixed for long. In May 2025, the EPA announced it would keep the PFOA and PFOS limits but intended to rescind the standards for PFHxS, PFNA, HFPO-DA, and the hazard index mixture, arguing the 2024 rule had used an improper procedure under the Safe Drinking Water Act.12EPA. Per- and Polyfluoroalkyl Substances (PFAS) On May 18, 2026, the EPA published two proposed rules carrying that through. The first would formally rescind the determinations and MCLs for those four compounds, with public comment open until July 20, 2026.15EPA. Proposed PFAS Rescission Rule The second would let water systems request a two-year extension of the PFOA and PFOS compliance deadline, pushing it from April 2029 to April 2031, though systems with PFOA or PFOS levels at or above 12 parts per trillion would still have to take short-term mitigation steps during the exemption.16EPA. Proposed PFOA and PFOS Compliance Extension Rule
The 2024 rule is also in court. In American Water Works Association et al. v. EPA, pending in the D.C. Circuit, chemical industry and water utility groups are seeking to overturn the standards, with the Natural Resources Defense Council and Earthjustice intervening to defend the rule. On January 21, 2026, the court denied a motion for partial vacatur. Briefing is complete and oral arguments are expected in fall 2026.17NRDC. American Water Works Association et al. v. EPA: Forever Chemicals in Tap Water
Superfund Designation
Separately from the drinking water standards, the EPA designated PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, better known as Superfund) in a final rule effective July 8, 2024. The designation lets the agency compel polluters to pay for cleanup under the “polluter pays” principle instead of drawing on taxpayer-funded Superfund money. Any release of PFOA or PFOS meeting or exceeding one pound within 24 hours now has to be reported to the National Response Center and relevant state and local emergency agencies.18Federal Register. Designation of PFOA and PFOS as CERCLA Hazardous Substances The EPA has said it will focus enforcement on parties that significantly contributed to contamination and does not intend to pursue farmers, municipal landfills, water utilities, municipal airports, or local fire departments where equitable factors do not support doing so.19EPA. Questions and Answers About Designation of PFOA and PFOS as Hazardous Substances Under CERCLA
The designation is being challenged too. The U.S. Chamber of Commerce, the National Waste and Recycling Association, and the Associated General Contractors of America filed Chamber of Commerce v. EPA, No. 24-1193, in the D.C. Circuit, arguing the EPA misinterpreted its authority, failed to perform a proper cost-benefit analysis, and imposed unconstitutional retroactive liability. The court granted a stay in February 2025 while the incoming administration reviewed the rule, but the EPA announced in September 2025 that it would retain and defend the designation. The stay was lifted in October 2025, with final briefs due in December 2025.20American Bar Association. EPA’s CERCLA Hazardous Substance Designation
The Major Lawsuits and Settlements
The central arena for PFAS litigation has been a multidistrict litigation in federal court in South Carolina, In Re: Aqueous Film-Forming Foams Products Liability Litigation (MDL 2873), before Judge Richard M. Gergel. The MDL consolidates thousands of claims from public water systems, individuals, and government entities against AFFF and PFAS manufacturers. Several landmark settlements have come out of it.
3M: Up to $12.5 Billion
3M reached the largest settlement, agreeing to pay between $10.5 billion and $12.5 billion (pre-tax present value of $10.3 billion) to public water systems that have detected PFAS or may do so in the future. The settlement received final court approval on March 29, 2024, with payments structured over 13 years through 2036.213M. 3M Settlement With Public Water Suppliers to Address PFAS Phase One, covering systems with impacted water sources as of June 2023, was allocated $6.875 billion. Phase Two, covering systems required to test under federal monitoring rules or serving more than 3,300 people, was allocated between $3.625 billion and $5.625 billion, with several Phase Two claim deadlines falling in mid-2026.22PFAS Water Settlement. 3M Frequently Asked Questions
DuPont, Chemours, and Corteva: $1.185 Billion
DuPont and its corporate successors Chemours and Corteva agreed to a $1.185 billion settlement fund for public water systems, with Chemours paying 50%, DuPont roughly $400 million, and Corteva roughly $193 million. The federal court in South Carolina approved it in early 2024.23Association of State Drinking Water Administrators. Judge Approves Settlement Requiring DuPont, Chemours, and Corteva to Pay $1.1 Billion in PFAS Contamination Suit In August 2025, the same three companies announced a separate $875 million settlement (about $500 million in present value) with the State of New Jersey to resolve environmental and PFAS claims involving four contaminated sites and statewide AFFF contamination, with payments structured over 25 years.24Chemours. Chemours, DuPont, and Corteva Reach Agreement With the State of New Jersey
Tyco Fire Products: $750 Million
Tyco Fire Products, a major AFFF manufacturer, agreed in April 2024 to pay $750 million to resolve PFAS claims from public water systems. An initial $250 million was contributed in June 2024, with the remaining balance adjusted for insurance recoveries. The settlement covers claims against Tyco, Chemguard, and related entities and does not include an admission of liability.25PFAS Water Settlement. Frequently Asked Questions – Tyco
BASF: $316.5 Million
BASF entered a class settlement in May 2024 for $312.5 million to resolve PFAS claims from public water systems with measurable contamination, plus $4 million for administrative costs. The claims payment was made in March 2025.26BASF. BASF Corporation Enters Class Settlement With U.S. Public Water Systems
State Attorneys General
Beyond the federal MDL, attorneys general from 31 states and Washington, D.C. have sued PFAS manufacturers as of late 2024.27National Conference of State Legislatures. Per- and Polyfluoroalkyl Substances Minnesota’s attorney general sued 3M in 2010, producing an $850 million settlement in 2018, with roughly $720 million allocated for drinking water and natural resource projects in the Twin Cities metropolitan area.283M Settlement State of Minnesota. 3M Settlement 3M also reached a separate New Jersey settlement valued at up to $450 million, announced in May 2025.29Steptoe. PFAS Lawsuits on the Rise: Trends, Risks, and Takeaways
One important boundary: the water-system settlements do not resolve personal injury lawsuits from individuals alleging health effects from PFAS exposure. Those cases remain active.30Manufacturing Dive. 3M PFAS Water Supply Contamination Settlement Final Approval By January 2026, 3M had paid nearly $14 billion to settle PFAS-related litigation and invested $1 billion globally in water treatment technologies.31Fox 9. 3M Says It’s No Longer Manufacturing PFAS Chemicals
State Regulation
States have not waited for Washington. At least 11 have enacted enforceable drinking water standards for certain PFAS compounds, and 16 have adopted advisory or notification levels, with some state limits stricter than the federal MCLs.27National Conference of State Legislatures. Per- and Polyfluoroalkyl Substances Sixteen states have passed laws phasing out PFAS-containing AFFF firefighting foam. Washington state banned PFAS in food contact packaging in 2018 and in cosmetics and personal care products effective January 2025.32Washington Department of Health. PFAS Consumer Products New Hampshire enacted a broad ban effective January 2027 covering food packaging, children’s products, textiles, cosmetics, and upholstered furniture.33New Hampshire PFAS. PFAS Consumer Products Connecticut and Massachusetts became the first states to ban PFAS in firefighting protective gear in 2024, and six other states have followed.
Reducing Your Exposure at Home
Three filtration technologies have been shown to reduce PFOA and PFOS in tap water: granular activated carbon filters, reverse osmosis systems, and ion exchange resins. The EPA recommends looking for products certified to NSF/ANSI Standard 53 (carbon and ion exchange) or NSF/ANSI Standard 58 (reverse osmosis) specifically for PFAS reduction.34EPA. Reducing PFAS in Your Drinking Water With a Home Filter To make a PFAS reduction claim, a certified filter must bring PFAS below 20 parts per trillion, though current certification standards do not yet guarantee removal down to the 4.0 ppt federal MCL.35NSF International. PFAS and Drinking Water
Boiling water does not remove PFAS and may actually increase concentrations. Conventional water softeners and standard iron filtration systems are also ineffective. Point-of-use systems that treat water at a single faucet tend to be more economical than whole-house systems, with costs ranging from roughly $20 to over $1,000 before ongoing filter replacement.34EPA. Reducing PFAS in Your Drinking Water With a Home Filter
If you want help paying for testing or treatment, the Infrastructure Investment and Jobs Act directs $9 billion specifically for PFAS and emerging contaminants: $4 billion through the Drinking Water State Revolving Fund and $5 billion through an EPA grant program for small or disadvantaged communities, with states able to leverage an additional $12 billion in existing revolving fund resources.13EPA. PFAS NPDWR Fact Sheet: Cost and Benefits The EPA has also made $1 billion available to help states, territories, and private well owners with testing and treatment.12EPA. Per- and Polyfluoroalkyl Substances (PFAS)