Contaminants Compass provides updates, legal observations and actionable tips to navigate the evolving legal challenges of per- and polyfluoroalkyl substances (PFAS) and similar chemicals and products.
This edition addresses:
- EPA’s further delay in reporting obligations under the Toxic Substances Control Act (TSCA)
- EPA’s proposal to add microplastics as a priority contaminant group in its Sixth Contaminant Candidate List under the Safe Drinking Water Act (SDWA)
- A recent ruling by the U.S. Court of Appeals for the D.C. Circuit denying EPA’s request to sever and stay challenges to the agency’s drinking water maximum contaminant levels (MCLs) for four PFAS chemicals
- Updates from the ongoing U.S. Chamber of Commerce litigation challenging EPA’s CERCLA designation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)
- A dismissal by a federal court in Connecticut on inadequate causation allegations
- An update on New Mexico’s product-labeling rules
- New theories in litigation concerning PFAS in firefighting gear
Look for new editions every month, and feel free to reach out to the McGuireWoods PFAS & Emerging Contaminants Practice Area with questions regarding PFAS issues.
I. Federal Regulatory
EPA Delays PFAS Reporting Rule Start Date
On April 13, 2026, EPA issued a final rule delaying the submission period for manufacturers to report certain PFAS data under TSCA. The original PFAS Reporting Rule, finalized in October 2023, required manufacturers and importers to report data on PFAS manufactured or imported between 2011 and 2022. EPA issued a proposed update in November 2025 that introduced exemptions for PFAS present at a “de minimis” threshold or below 0.1% in certain products along with reporting clarifications. The proposed updates aim to reduce the compliance burden on industry while retaining the agency’s ability to collect important information on PFAS use and safety.
The data submission period was set to run for a six-month window from April 13 to Oct. 13, 2026. EPA, however, is still working to finalize the PFAS Reporting Rule amendments and is modifying the submission window to begin either Jan. 31, 2027, or 60 days following the effective date of the upcoming final rule, whichever is earlier. EPA states that it expects to promulgate the final rule before Jan. 31, 2027, and will add an effective date that supersedes the Jan. 31, 2027, backstop date at that time.
Microplastics Included in Draft of Sixth Drinking Water Contaminant Candidate List
In a draft rule published on April 6, 2026, EPA proposed to include microplastics as a priority contaminant group in its Sixth Contaminant Candidate List (CCL) under the SDWA.
The CCL includes contaminants that are not currently subject to national drinking water regulations but are known or anticipated to occur in public water systems and may require future regulation under the SDWA. The CCL functions as an “initial screening of contaminants” on which EPA will focus research and data collection regarding impacts on human health. This is the first in a series of steps EPA uses to assess whether a particular contaminant merits regulation under the SDWA. EPA uses the CCL to determine whether to include a contaminant in the Unregulated Contaminant Monitoring Rule (UCMR), which is limited to 30 new contaminants. EPA will gather additional nationally representative occurrence data on contaminants included in the UCMR. EPA then evaluates contaminants on the CCL with sufficient information to determine whether regulation under the SDWA is appropriate based on three criteria: (1) whether the contaminant may have an adverse effect on human health; (2) whether the contaminant is known to occur, or there is a substantial likelihood it occurs, in public water systems at a frequency and level concerning to human health; and (3) whether the administrator determines regulation presents a meaningful opportunity to reduce human health risks. The administrator is required to determine whether at least five contaminants on the CCL should be regulated under the SDWA. This series of evaluations occurs every five years, with the last CCL published in 2022. The draft Sixth CCL includes 75 chemicals, four chemical groups (including microplastics) and nine microbes.
Comments on the proposed rule are due on June 5, 2026.
II. Federal Litigation
D.C. Circuit Denies EPA’s Request to Sever and Stay Challenges to Drinking Water Standards for PFAS
On March 19, 2026, the U.S. Court of Appeals for the D.C. Circuit denied EPA’s request to sever and stay challenges to the agency’s drinking water maximum contaminant levels (MCLs) for four PFAS in American Water Works Association v. EPA.
In the underlying action, industry groups are challenging EPA’s rule establishing MCLs for six PFAS promulgated in 2024. In May 2025, EPA announced its intent to keep MCLs in place for PFOA and PFOS and to rescind MCLs for the other four known as “Index PFAS.” EPA requested a stay pending regulatory developments and, in February, sent a rule proposing to rescind the Index PFAS to the Office of Management and Budget for review.
The court ultimately rejected EPA’s stay request without issuing an opinion. Water utilities argued that the issues have been fully briefed and that a stay would further delay resolution while the Index PFAS MCLs would remain in place, thereby prejudicing petitioners. Environmental groups intervening in support of the rule also opposed the stay and severance, arguing that Index PFAS issues are intertwined with issues related to PFOA and PFOS and therefore cannot be severed and that intervenors would be prejudiced by abeyance as well.
Post-Oral-Argument Letters of Supplemental Authority in PFAS Hazardous Substance Designation Challenge
The U.S. Chamber of Commerce and other trade groups continue to challenge EPA’s designation of PFOA and PFOS as hazardous substances under Section 102(a) of CERCLA in Chamber of Commerce v. EPA and following EPA’s announcement last year that it intends to retain the prior administration’s designations. As reported in March, the D.C. Circuit heard oral arguments in January 2026. In February, the petitioners filed a notice of supplemental authority alerting the court to a recent Fifth Circuit per curiam decision vacating a U.S. Department of Transportation rulemaking that relied on a study not disclosed during the notice-and-comment period. The petitioners argue that the D.C. Circuit should similarly find that EPA unlawfully relied on “critical material” that it failed to disclose during the rulemaking. Specifically, the petitioners point to new cost-benefit analyses introduced in the final rule that they allege contradict EPA’s prior stance that it could not legally consider nor was it able to quantify certain costs in promulgating the designations.
EPA and environmental organization respondents argue that the one-and-a-half-page Fifth Circuit decision is inapposite because the agency in that case “conceded” it had violated the APA when it relied on a study that it did not make available for notice and comment, stated its attempt to rescind the challenged rule and agreed to vacatur. Those defending the rule argue that here, in contrast, the agency continues to defend the designation and disputes that the cost estimates cited by petitioners were critical to the agency’s decision-making.
The case is otherwise pending the court’s decision.
Connecticut Federal Court Dismisses Putative Class Action Alleging Liability for Water Contamination Without Leave to Amend
On March 27, 2026, the U.S. District Court for the District of Connecticut granted defendant Kimberly-Clark Corporation’s motion to dismiss without leave to amend a proposed class action claiming the company polluted a Connecticut town’s water and soil with PFAS. Six plaintiffs from a Connecticut town alleged that Kimberly-Clark’s paper mill, which has operated on a 60-acre parcel along the Housatonic River for over 50 years, released PFAS chemicals through two mechanisms: disposal of “short fiber paper sludge” waste at the company’s nearby 165-acre landfill and smokestack emissions from the facility. The plaintiffs brought claims of negligence, medical monitoring, public and private nuisance, recklessness or willful and wanton conduct, strict liability, and violation of the Connecticut Unfair Trade Practices Act.
The court dismissed all claims after concluding that the plaintiffs failed to adequately substantiate their claims that PFAS contamination was caused by Kimberly-Clark. The court found that the plaintiffs relied on unsupported assumptions that Kimberly-Clark must have used PFAS chemicals simply because its products “traditionally” or “typically” involved such chemicals and that the sludge waste from the company’s landfill must have been “PFAS-laden” merely because such waste is “notorious” for containing PFAS. The court similarly rejected claims that smokestacks released PFAS through emissions, finding it speculative to infer PFAS emissions at the New Milford facility “merely because other smokestacks at other facilities in other states were confirmed to be emitting PFAS.” The court also noted that the plaintiffs failed to allege that even traceable levels of PFAS were detected in the Housatonic River at the point where water is drawn into the facility, rejecting their claims that defendants’ facilities created a “continuous cycle of pollution.”
Finally, the court found that the plaintiffs failed to establish that Kimberly-Clark’s conduct was a substantial factor in their alleged injuries, which included loss of enjoyment and diminution in value of their property and drinking wells based on tests showing PFAS contamination, as well as subclinical injuries including an increased risk of developing cancer and other illnesses linked to PFAS chemical exposure. The court explained that judicially noticeable testing conducted by the Aquarion Water Company showed comparable levels of PFAS in drinking water across the state, undermining claims that PFAS levels in the area were in fact elevated.
Having determined that the plaintiffs’ claims would be dismissed, the court declined to grant leave to amend, reasoning that the plaintiffs had already been afforded the opportunity to amend their claims three times and that attempts to further amend would be futile given the fundamental flaws in their causation theories.
This decision is in line with a recent trend in which courts probe testing data and related issues at the motion-to-dismiss stage.
III. State Regulatory
New Mexico’s PFAS Product Labeling Requirement Update
On March 23, 2026, the New Mexico Environmental Improvement Board announced that it voted to finalize the nation’s first broadly applicable PFAS labeling rules. These regulations were passed under New Mexico’s PFAS Protection Act, enacted in 2025, which phases in restrictions on the sale of products with intentionally added PFAS.
The labeling regulations will go into effect on Jan. 1, 2027, and require manufacturers to display a PFAS-identifying symbol on any product containing intentionally added PFAS. Exempted categories include medical devices and drugs, veterinary products, pesticides and other products subject to Federal Insecticide, Fungicide, and Rodenticide Act labeling requirements, and used products that are sold or resold.
As previously reported, the New Mexico Environment Department issued proposed regulations in October 2025 following the New Mexico Legislature’s passage of the PFAS Protection Act and later updated them in January and February 2026 ahead of a public hearing before the Environmental Improvement Board. The final text of the rule is pending public release.
IV. State Litigation
RICO and Consumer Protection Lawsuit Filed Against Chemical Companies and Firefighting PPE Manufacturers
On March 18, the county of San Mateo, California, filed a putative class action complaint against more than 20 defendants, including manufacturers of firefighter personal protective equipment (PPE). The lawsuit alleges that defendants manufactured, marketed and sold firefighter “turnout gear,” including hoods, helmets, coats, pants, gloves, boots and reflective tape, that was treated with PFAS despite knowing for “decades” that PFAS posed serious health risks. The complaint asserts that defendants fraudulently concealed this information from fire departments and the public while continuing to profit from the sale of contaminated equipment.
This case presents a new set of claims against companies producing PFAS and PFAS-containing PPE, including civil RICO violations, common law conspiracy, strict product liability for design defect and failure to warn, fraudulent concealment and negligent misrepresentation, breach of express and implied warranties, negligence, unjust enrichment, and violations of California’s Unfair Competition Law and False Advertising Law.
The county also seeks damages, equitable and injunctive relief, and class certification on behalf of all similarly situated public entities for purchase of materials beyond PFAS-containing firefighting foam. It alleges that PFAS in the PPE is not contained or stable and off-gasses, degrades and migrates when exposed to heat, ultraviolet light, water and routine wear associated with firefighting. The county asserts this equipment is contaminating fire stations, equipment and personal property while exposing firefighters to dangerous levels of toxic chemicals.
An initial case management conference is set for June 17, 2026.