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August 31, 2026 | Legal Update

Welcome to the August edition of Nutter’s Environment & Energy Insights, a periodic update of current trends in environment and energy law. This month we cover:

• The Environmental Appeals Board orders a remand for EPA Region 1 to consider whether PFAS limits have to be set in Manchester’s NPDES permit
• D.C. Circuit issues ruling on CERCLA hazardous substance designation for certain PFAS substances

Environmental Appeals Board Sends Manchester NPDES Permit Back to EPA Region 1 Over PFAS

The Environmental Appeals Board (“EAB”) is requiring EPA Region 1 to reexamine PFAS in the City of Manchester's wastewater discharge to the Merrimack River in New Hampshire.

The August 12, 2026 decision in In re City of Manchester, NPDES Appeal No. 25-04 (EAB Aug. 12, 2026) came out of a challenge by Conservation Law Foundation (“CLF”) to the renewed NPDES discharge permit for Manchester's wastewater treatment plant. Among other objections, CLF argued that the Region clearly erred by not considering whether limits on PFAS were necessary to achieve compliance with New Hampshire’s narrative water quality standards.

EPA Regulations – “Reasonable Potential”

EPA regulations require that NPDES permits “achieve water quality standards…including State narrative criteria for water quality.” As summarized by the EAB, in cases where a potential pollutant of concern has been identified in a discharge through monitoring, EPA must either (a) establish a water quality-based effluent limitation (“WQBEL”) or (b) conduct a reasonable potential analysis to determine whether a WQBEL is necessary. Further, if there is no numeric water quality criterion for the pollutant of concern, but the pollutant contributes to a violation of a narrative water quality criterion, the permit issuer must establish a WQBEL under 40 C.F.R. § 122.44(d)(1)(vi).

Permitting History

In this case, Region 1 identified PFAS as a potential pollutant of concern in the draft permit fact sheet. In addition to New Hampshire’s EPA-approved narrative criteria prohibiting injurious toxic substances or bioaccumulate in fish in harmful levels, New Hampshire had adopted numeric water quality criteria for four PFAS chemicals, but those criteria had not yet been adopted by the EPA as of the date of the permit decision. In its challenge, CLF also submitted monitoring data showing PFAS was present in the facility’s discharge. In response, the Region repeatedly stated in its response to comments that because the EPA had not approved New Hampshire’s PFAS numeric water quality criteria, it could not conduct a reasonable potential analysis at all — as there was “no standard to apply.” It then issued the permit, and CLF subsequently appealed. 

EAB’s Holding

The EAB held that the Region’s conduct directly contradicted the regulatory requirement in 40 C.F.R. § 122.44(d) to include conditions in the permit necessary to achieve water quality standards, including a state’s narrative water quality criteria. As discussed above, when a potential pollutant of concern is identified but no approved numeric criterion yet exists for the pollutant, 40 C.F.R. § 122.44(d)(1)(vi) requires that a reasonable potential analysis be conducted to establish a WQBEL. As a result, the EAB concluded that the Region’s failure to conduct a reasonable potential analysis where narrative standards for PFAS existed was clear error. Notably, in its remand to the Region, the EAB did not order PFAS effluent limits. Rather, it ordered the Region to create a new record demonstrating compliance with 40 C.F.R. § 122.44(d)(1).

Impact on NPDES Permitting

In general, permit issuers and permittees should now expect to pay specific attention to PFAS related testing and regulations as part of the permitting process. If PFAS are present or suspected in a facility’s effluent, permit issuers likely must now follow 40 C.F.R. § 122.44(d)(1)(vi) in conducting a reasonable potential analysis or establish a WQBEL. And, any monitoring data existing for PFAS at a facility, whether collected voluntarily or through a prior permit’s monitoring requirements, may now trigger a reasonable potential analysis.

D.C. Circuit Upholds EPA’s PFOA/PFOS Hazardous Substance Designation

Chamber of Commerce v. EPA, No. 24-1193 (D.C. Cir. Aug. 18, 2026)

On August 18, the D.C. Circuit denied consolidated petitions for review of EPA's May 2024 rule designating PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The designation stands, and with it the full CERCLA liability, reporting, and cost-recovery regime as applied to these two PFAS compounds.

Under CERCLA, EPA may directly designate certain substances as “hazardous substances,” which would then allow EPA and others affected by the substances to compel responsible parties to cleanup releases of that substance. The petitioners advanced three challenges to the May 2024 “hazardous substance” designation: (1) EPA misinterpreted the term “may present substantial danger” in CERCLA’s definition of a hazardous substance; (2) EPA’s cost-benefit analysis provided insufficient notice to parties; and (3) EPA’s cost-benefit analysis and decision to regulate in the face of uncertainty were arbitrary and capricious. The D.C. Circuit denied all three challenges.

“Substantial Danger”

Industry petitioners argued EPA had to find that substantial danger “will” result from a release. The court instead agreed with EPA’s view of the statute, which allows EPA to make the designation if the substance “may” present a substantial danger. The court held the statutory texts straightforwardly uses “may,” which is a word of contingency, and Congress wrote CERCLA to operate on scientific probability rather than certainty. Notably, the petitioners never disputed that PFOA and PFOS themselves meet the “substantial danger” standard.

“Hazardous Substances vs. Pollutant or Contaminant”

The petitioners next argued that the definition of “hazardous substances” must be read more narrowly than “pollutant or contaminant” because CERCLA confers more authority to address hazardous substances. The court rejected the argument, finding that both definitions require a probability of “substantial danger” and any difference between the categories is procedural. The court also noted that a substance can move from one category to the other as the science develops, which is the “belt and suspenders approach” that CERCLA’s text and context “straightforwardly allow.”

“Non-Delegation and Void for Vagueness”

Lastly, the petitioners contended that EPA’s interpretation of the statute conferred too much undefined authority on EPA and thus did not satisfy the nondelegation and void-for-vagueness doctrines. In rejecting the nondelegation argument, the court stated that “allowing agencies to make discretionary judgments informed by evidence fully comports with the…doctrine so long as Congress has set out an ‘intelligible principle’ to guide what it has given the agency to do.” Accordingly, Congress’ general policy for EPA to regulate harmful substances and the environment, the fixed boundaries of CERCLA, and the requirement to tie EPA’s decisions to scientific findings all satisfied this requirement.

The court also upheld the cost-benefit analysis conducted by EPA in connection with its determinization.

Practical Implications

The decision confirms that the “hazardous substances” designation for PFOA and PFOS remain in force and will continue to be subject to CERCLA. The court’s decision also seemingly confirms that EPA may designate additional PFAS substances as “hazardous” under CERCLA in the future.

This advisory was prepared by Matthew Connolly, Alexander Eddinger, and Matthew Snell in Nutter’s Environment and Energy practice group. If you would like additional information, please contact any member of our practice group or your Nutter attorney at 617.439.2000.

This update is for information purposes only and should not be construed as legal advice on any specific facts or circumstances. Under the rules of the Supreme Judicial Court of Massachusetts, this material may be considered as advertising.