State of Play: Forever Chemicals and Drinking Water

When toxic chemicals contaminate drinking water supplies, public water providers are the first line of defence. They are responsible for delivering drinking water to their communities that meets all state and federal standards established to protect human health and the environment from the range of threats posed by those contaminants. Sometimes, they must move faster than the regulators in order to remove or reduce emerging contaminants that have not yet been regulated.

The financial burdens associated with providing that first line of defence are substantial, and many public entities turn to the courts to hold accountable the corporations whose past conduct can be tied to the contamination. This overview looks at two types of contaminants, PFAS and 1,4-dioxane, some of the cases that have been brought to address them, and a few regulatory developments at the federal level.

The persistence of PFAS, and PFAS litigation

In summer 2025, thousands of public water systems across the United States began receiving the first award instalments from the landmark, USD10.5–USD12.5 billion settlement with the 3M Company over litigation concerning PFAS contamination. By the autumn, those same public entities were receiving awards under the parallel USD1.85 billion settlement with DuPont de Nemours, Inc, The Chemours Company and Corteva, Inc. There are also pending settlements with Tyco Fire Products (USD700 million) and BASF Corporation (USD312.5 million).

Combined, these settlements represent the largest in history for drinking water contamination. They were resolved through the Aqueous Film-Forming Foam (AFFF) Products Liability Litigation (MDL 2873) overseen by the United States District Court for District of South Carolina, Judge Richard M. Gergel presiding. PFAS is shorthand for per- and polyfluoroalkyl substances. They are called “forever chemicals” because they do not break down naturally; they persist and migrate through the environment and are associated with numerous human health effects, including cancer. According to the MDL web site maintained by the US District Court in South Carolina:

“Plaintiffs generally allege that aqueous film-forming foams (AFFFs) containing perfluorooctanoic acid (PFOA) and/or perfluorooctane sulfonate (PFOS), two types of PFAS, contaminated groundwater near various military bases, airports, and other industrial sites where AFFFs were used to extinguish liquid fuel fires. The plaintiffs allege that they were caused personal injury, a need for medical monitoring, property damage or other economic losses.”

The public water systems are just one group of plaintiffs participating in the MDL. There remain at least three more plaintiff classes:

• personal injury claims;
• property damage claims; and
• claims brought by attorneys general of more than 30 states.

All allege, at least in part, manufacturers’ failure to warn of the harm associated with PFAS in spite of their superior knowledge. The first bellwether for personal injury cases was scheduled for October 2025 but has been postponed to allow more unfiled cases to join the MDL.

The MDL moving through US District Court in South Carolina comprises only part of the PFAS litigation picture. A few things to consider and watch now follow.

• There are thousands more PFAS compounds beyond PFOA and PFOS. Some are already regulated, many are under investigation, and detections for some are just emerging and will continue to do so in the years ahead. It is unclear whether existing treatment technology designed for the removal of PFOA and PFOS will be sufficient for any/all additional PFAS compounds that need to be reduced or removed to ensure public health and safety. But it is clear that contamination from these additional compounds is extensive. It remains to be seen just how expensive treatment will be as investigations continue.
• Public entities across the country have also initiated litigation against the PFAS manufacturers mentioned here, as well as other corporate defendants, who are responsible for PFAS contamination in the environment, including water supplies. Examples include the following.
1. New Jersey v DuPont – New Jersey Attorney General Matthew Platkin announced a historic settlement worth more than USD2 billion with 3M, Solvay and the DuPont companies, the largest environmental settlement ever by an individual state, settling claims related to discharges at four sites across New Jersey, as well as claims associated with AFFF contamination.
2. Minnesota v 3M – In 2018, Minnesota Attorney General Lori Swanson announced a USD850 million settlement with 3M Company for PFAS contamination in Twin Cities’ suburbs. The contamination was the result of the chemicals leaching into the groundwater from landfills where they had been dumped.
3. Texas v 3M and DuPont – Texas Attorney General Ken Paxton filed a lawsuit against 3M Company and the DuPont companies, alleging that “Defendants have engaged in deceptive trade practices by failing to disclose health risks and environmental harms associated with their products, and representing and/or implying their products were ‘safe’ in a false, deceptive, or misleading manner, in violation of the Texas Deceptive Trade Practices–Consumer Protection Act.” Products specifically mentioned include Teflon, Scotchgard and Stainmaster.
4. Maryland v W.L. Gore & Associates – Maryland Attorney General Anthony Brown filed a lawsuit against W.L. Gore & Associates, manufacturer of the GORE-TEX waterproof fabric, for knowingly releasing PFOA into the environment in violation of the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and state law.
5. Michigan v Tribar Technologies – Michigan Attorney General Dana Nessel filed a lawsuit against Tribar Technologies, Inc and Adept Plastics Finishing, Inc alleging that the two auto supply companies illegally discharged contaminated water, which reached and contaminated Michigan waters, resulting in repeated violations of the water and air pollution standards of Michigan’s Natural Resources and Environmental Protection Act. Contaminants at issue include perfluorooctane sulfonate (PFOS) and hexavalent chromium.
6. New Mexico v Air Force – New Mexico’s Department of the Environment and Department of Justice have sued the United States Air Force in multiple forums to require the Air Force to stop discharging PFAS into the environment and to require meaningful efforts to remediate past discharges. The Department notes that: “The Air Force has spent years contesting the Environment Department’s authority as opposed to any meaningful cleanup of the toxic PFAS contamination in local drinking water sources that serve both residents and dairy farmers.”

The emergence of 1,4-dioxane, and 1,4-dioxane litigation

1,4-Dioxane has been widely used since the 1950s as a component in, or by-product of, certain industrial and commercial products. In the United States, there have been two principal sources of the 1,4-dioxane groundwater contamination now emerging in hotspots across the country: chlorinated solvent stabilisation and ethoxylated surfactants.

• Solvent stabilisation – The Dow Chemical Company and Vulcan Materials Company used 1,4-dioxane as a stabiliser for chlorinated solvents, primarily 1,1,1-trichloroethane (TCA), until the 1990s. PPG also formulated TCA with 1,4-dioxane for a short period. 1,4-Dioxane itself was primarily manufactured by the Dow Chemical Company, Ferro Corporation, and Union Carbide (since merged with Dow).
• Ethoxylated surfactants – 1,4-Dioxane is generated as a by-product of ethoxylated surfactants and thus occurs as an impurity in certain consumer products, such as detergents, soaps, laundry pre-soaks, automotive antifreezes, and shampoos.

The Environmental Protection Agency (EPA) considers 1,4-dioxane as “likely to be carcinogenic to humans”, and similar conclusions have been reached by the US Department of Health and Human Services, as well as the International Agency for Research on Cancer.

The regulatory landscape for 1,4-dioxane is developing and evolving rapidly. In November 2024, the EPA issued a final Unreasonable Risk Determination for 1,4-Dioxane, stating that, “EPA has determined that 1,4-dioxane presents an unreasonable risk of injury to health under the conditions of use”. It continued:

“EPA’s final determination is based on cancer and non-cancer risks… to workers and occupational non-users (ONUs) from inhalation and dermal exposures, and cancer risks to the general population, including fenceline communities, from exposures to 1,4-dioxane in drinking water sourced from surface water contaminated with industrial discharges of 1,4-dioxane (including when it is generated as a byproduct).”

That determination was made during the Biden Administration pursuant to the process for conducting chemical risk evaluations outlined under the Toxic Substances Control Act. Under the Trump Administration, EPA Administrator Zeldin proposed a substantial revision to that rule, and the impact of that process on EPA’s view of 1,4-dioxane could change as a result. More on that below.

In addition to evolving regulatory frameworks at the federal level, states are beginning to regulate 1,4-dioxane. In 2020, New York established an MCL for 1,4-dioxane in drinking water at 1 part per billion (ppb), the first state to do so. This is the most stringent enforceable standard for this chemical in drinking water in the nation. New York also has separate regulations for 1,4-dioxane limits in consumer products, with a lower limit for household cleaning and personal care products than for cosmetics.  California and New Jersey are considering doing the same and have initiated their respective processes for that consideration. It is presumed that other states are beginning to investigate their options and needs related to the contaminant.

While 1,4-dioxane contamination of groundwater may not be as ubiquitous as PFAS contamination, treating it is extremely expensive. Conventional treatment methods like granular activated carbon (GAC) - which water systems use to remove PFAS - cannot successfully remove 1,4-dioxane. Instead, 1,4-dioxane removal requires an advanced oxidation process (AOP) followed by removal with GAC of the by-products of AOP treatment. This two-step process involves high capital investment up front, in addition to substantial ongoing operating and maintenance costs.

In December 2017, the Suffolk County Water Authority (SCWA) filed a lawsuit against the Dow Chemical Company, Ferro Corporation, Vulcan Materials Corporation, Proctor & Gamble, and Shell Oil Company, over 1,4-dioxane contamination in the Long Island groundwater that supplies drinking water to approximately 1.2 million residents. SCWA is the largest water provider on Long Island, and the largest water provider in the United States relying entirely on groundwater supply. Dow was the largest producer of dioxane-stabilised TCA in the United States; Ferro was one of Dow and Vulcan’s largest dioxane suppliers; and P&G and Shell manufactured some of the most popular dioxane-containing consumer products on the market, including Tide laundry detergent.

SCWA’s complaint alleges that the defendants knew or should have known that the industrial degreasers, laundry detergents and other household products they made, distributed or sold are dangerous to human health and contain unique characteristics that cause extensive and persistent environmental contamination.

SCWA has resolved its case against some of the defendants, and earlier this year, the Court (Gershon, J) denied virtually all of the defendants’ Daubert and summary-judgment motions, refusing to exclude any of SCWA’s experts or to dismiss its claims for public nuisance, failure to warn and trespass. SCWA v Dow Chem Co, No 17-CV-6980 (NG) (JRC), 2025 WL 1907206 (E.D.N.Y. 10 July 2025).

In March 2023, New Jersey Attorney General Matthew Platkin filed a lawsuit against the Dow Chemical Company, Ferro Corporation and Vulcan Materials Company for widespread 1,4-dioxane contamination across New Jersey, becoming the first state in the nation to do so.

The complaint alleges that the defendants “knowingly and willfully manufactured, promoted, and/or sold products containing 1,4-dioxane” in New Jersey with knowledge that 1,4-dioxane was harmful and “would inevitably reach surface water and groundwater in substantial quantities, significantly pollute drinking water supplies, render drinking water unusable and unsafe, threaten the public health and welfare, and harm other natural resources, as it has done with respect to the water resources in New Jersey.”

New Jersey prevailed on its motion to remand its case, so pending motions to dismiss will be heard in state court. In addition to the Suffolk County Water Authority and the State of New Jersey, 29 individual public water providers have brought similar cases for 1,4-dioxane contamination of water supplies in New Jersey and New York.

Regulatory developments to watch

In May 2025, EPA Administrator Lee Zeldin announced that the agency will keep the Maximum Contaminant Levels (MCL) for both PFOA and PFOS that were established by an April 2024 final rule under the National Primary Drinking Water Regulations (NPDWR). The rule established an MCL of 4.0 parts per trillion for both PFOA and PFAS. The May 2025 announcement also included an extension of the compliance deadline for water providers to meet that MCL, moving the date back from 2029 to 2031. In the announcement, Administrator Zeldin stated:

“The work to protect Americans from PFAS in drinking water started under the first Trump Administration and will continue under my leadership. We are on a path to uphold the agency’s nationwide standards to protect Americans from PFOA and PFOS in their water. At the same time, we will work to provide common-sense flexibility in the form of additional time for compliance. This will support water systems across the country, including small systems in rural communities, as they work to address these contaminants. EPA will also continue to use its regulatory and enforcement tools to hold polluters accountable.”

In that same May 2025 announcement, EPA addressed several other PFAS compounds, stating its intent to “rescind the regulations and reconsider the regulatory determinations for PFHxS, PFNA, HFPO-DA (commonly known as GenX), and the Hazard Index mixture of these three PFAS plus PFBS to ensure the determinations and any resulting drinking water regulation follow the Safe Drinking Water Act process.”

In September 2025, EPA proposed a revision to the process for conducting risk evaluations for chemicals already in commerce under the Toxic Substances Control Act (TSCA). The proposed rule seeks to amend a 2024 regulation titled Procedures for Chemical Risk Evaluation under TSCA (the “2024 Risk Evaluation Framework Rule”). The proposed changes include the following.

• A requirement for EPA to make a determination of unreasonable risk for each of the conditions of use within the scope of the chemical’s risk evaluation, instead of a single risk determination on the chemical substance as a whole.
• Clarifications as to how EPA will consider occupational exposure controls such as personal protective equipment and industrial controls when conducting risk evaluations and making risk determinations.
• Clarifications regarding EPA’s discretionary authority to determine which conditions of use, exposure routes and exposure pathways it will consider in a risk evaluation.
• Revisions to certain regulatory definitions to ensure consistency with Executive Order 14303 Restoring Gold Standard Science and to ensure transparency and accountability in conducting risk evaluations.
• Revisions to the procedures and requirements EPA would follow when revising or supplementing risk evaluation documents to better enable EPA to meet the statutory deadlines to assess and manage risk.
• Adjustments to the process and information collection obligations for manufacturers (including importers) for requesting an agency-conducted TSCA risk evaluation.

At the time of publication of this chapter of the guide (27 November 2025), the proposed changes to the TSCA risk evaluation framework were open to public comment, and more action on this front is expected in 2026. All these regulatory developments are evolving rapidly and will likely impact the way litigators navigate the complexities of forever chemicals and drinking water in the days ahead.