Appellate Court Grants Industry Petitioners’ Petition for Review and Vacates Methylene Chloride Rule and Risk Determination

On September 15, 2026, the U.S. Court of Appeals for the Fifth Circuit granted Industry Petitioners’ petition for review of the U.S. Environmental Protection Agency’s (EPA) 2024 risk management rule for methylene chloride (MC). East Fork Enterprises v. EPA (No. 24-60227, consolidated with No. 24-60256). The court states that “[f]inding that errors of law occurred and substantial evidence did not support EPA’s decision,” it grants the Industry Petitioners’ petition for review, vacates EPA’s 2024 rule and associated risk determination, denies the Sierra Club’s petition for review, and remands to EPA for proceedings consistent with its opinion.

EPA’s Risk Evaluation and Risk Management Rule for MC

In President Trump’s first term, EPA published a final risk evaluation in June 2020 that covered 53 conditions of use (COU) for MC. The Trump EPA concluded that MC does not pose an unreasonable risk to the environment; poses an unreasonable risk to health for 47 COUs; and does not pose an unreasonable risk to health for the six other COUs.

On June 30, 2021, Michal Ilana Freedhoff, Ph.D., Assistant Administrator of the Biden EPA’s Office of Chemical Safety and Pollution Prevention (OCSPP), announced how EPA would move forward with the risk evaluations of the first ten chemicals evaluated under the amended Toxic Substances Control Act (TSCA), including MC. As reported later in EPA’s press release, the policy changes included:

• Whole Chemical Approach: In the final risk evaluations for the first ten chemicals, including MC, EPA made separate unreasonable risk determinations for each COU for each chemical. EPA withdrew the previously issued orders for those COUs for which no unreasonable risk was found, issued revised unreasonable risk determinations for these chemicals as a “whole substance,” and requested public comment.

• Use of Personal Protective Equipment (PPE): Unlike the first Trump Administration, which generally assumed in the final risk evaluations that PPE was always provided to and used by workers, the Biden EPA revisited this assumption. EPA acknowledged in its press release that this shift could impact conclusions about risk for some COUs for several chemicals, including MC.

• Expanding Consideration of Exposure Pathways and Fenceline Community Exposure Screening Level Approach: The Biden EPA noted that the previous Administration chose not to consider air, water, and soil contamination because these exposures are already regulated under other environmental laws such as the Clean Air Act (CAA), Safe Drinking Water Act (SDWA), and Clean Water Act (CWA). For six chemicals, including MC, the Biden EPA stated that it would identify risks posed by the chemicals to fenceline communities. If EPA determines that there is no unreasonable risk to fenceline communities, it will move forward to the risk management stage. If EPA finds that there may be an unreasonable risk that cannot be addressed without supplementing the risk evaluation or through the risk management approaches being considered, EPA will conduct a more comprehensive exposure assessment of fenceline communities and supplement the risk evaluation for that chemical with the new information.

In May 2023, the Biden EPA published a proposed risk management rule for MC. According to EPA, pursuant to TSCA Section 6(b), the Agency determined that MC presents an unreasonable risk of injury to health, without consideration of costs or other non-risk factors, including an unreasonable risk to potentially exposed or susceptible subpopulations identified as relevant to the 2020 MC evaluation, under the COUs. EPA published a final risk management rule in May 2024, prohibiting and restricting the manufacture (including import), processing, distribution in commerce, commercial use, and disposal of MC to prevent unreasonable risk of injury to health in accordance with TSCA Section 6(a).

The American Chemistry Council (ACC), East Fork Enterprises, and Epic Paint Company (Industry Petitioners) filed a petition for review, arguing that EPA exceeded its authority and that EPA’s conclusions are arbitrary and capricious and unsupported by substantial evidence. The Sierra Club filed a separate petition for review, arguing that EPA did not go far enough in protecting its members who live in fenceline communities, have cancer-favoring genetics, or live at altitudes where ozone depletion is a concern. The petitions for review were consolidated.

Standard of Review

The court notes that TSCA modifies the Administrative Procedure Act (APA) substantial-evidence standard: EPA actions must be “supported by substantial evidence in the rulemaking record taken as a whole.” The court cites the U.S. Court of Appeals for the District of Columbia Circuit’s 2024 decision in Vinyl Institute, Inc. v. EPA (No. 22-1089), stating that “[a]lthough the two statutes’ substantial evidence standards are similar textually, it is understood that the TSCA’s substantial evidence standard is ‘fairly rigorous and more searching than the APA standard.’”

“Whole Chemical” Risk Determination

Industry Petitioners argue that the Biden EPA’s “whole chemical determination” was unlawful because TSCA and EPA procedural rules both required EPA to publish a separate risk determination for each COU. The court states that “[t]he Industry Petitioners have the edge legally” as TSCA “provides that EPA must determine whether the manufacture, processing, distribution . . . use, or disposal of a chemical substance . . . or . . . any combination of such activities, presents an unreasonable risk. . . .” The court notes that each activity in connection with a particular chemical, or combination of activities, may or may not present unreasonable risk. The court concludes that EPA lacked legal authority under TSCA to determine that a chemical or substance poses unreasonable risk “as a whole” rather than to evaluate each of its COUs.

Assumption That Workers Do Not Wear PPE

Industry Petitioners claim that EPA violated TSCA by reversing its assumption in the June 2020 risk evaluation that all workers are always provided and appropriately wear PPE and that it acted without supporting evidence. In its decision, the court agrees, stating that according to TSCA, EPA must account for PPE in its risk evaluations as a COU if evidence reflects that PPE is actually used. According to the court, EPA’s only statutory rationale for abandoning its previous consideration of PPE as a COU is that it decided to factor PPE use instead as a limit on the intensity of the exposure in the “risk management” phase of regulation. The court notes that this is contrary not only to the definition of COU, “but also to EPA’s duty to formulate its unreasonable risk determination by considering the ‘intensity . . . of exposures under the conditions of use.’” The court was unpersuaded by EPA’s “speculation” that some subpopulations of workers may not be covered by U.S. Occupational Safety and Health Administration (OSHA) standards or that their employers failed to comply with OSHA requirements. Rather, the court stated that “[i]f one also considers EPA’s decision not to alter the exposure assessments when it revised its risk determination, these ‘explanations’ for assuming non-use of PPE are remarkably self-contradictory.”

EPA’s Legal Approach to “Unreasonable Risk”

Industry Petitioners maintain that EPA exceeded its statutory mandate to identify only “unreasonable” risks and to regulate “to the extent necessary” to eliminate “such [unreasonable] risks” by “essentially treat[ing] any risk as unreasonable and regulat[ing] far beyond what removing ‘unreasonable risk’ entails.” EPA’s defense of its methodology is that it applied conventionally approved techniques of appraising toxic risks, sought the “best available science,” and applied the weight of scientific evidence to evaluate risk. In any event, according to EPA, courts must generally defer to agency fact findings based on agencies’ technical expertise. The court states that EPA “confuses substantial evidence with statutory interpretation.” The court notes that “Congress insisted that the baseline [of unreasonable risk] be determined in light of numerous additional statutory provisions that expressly counsel EPA, inter alia, how to apply the science, how to gauge reliability of findings, and how to maintain transparency of agency decisionmaking.” The court states that “‘[u]nreasonable risk’ summarizes the legal conclusion that must be drawn from those parameters; it is not a cover for whatever numerical estimates EPA generates using the parameters.”

EPA’s Methodological Approach to “Unreasonable Risk”

The Industry Petitioners also challenge EPA’s assumptions and findings in the final risk determination and the menu of regulatory measures required to eliminate “unreasonable risk” “to the extent necessary.” According to the court, for these issues, the question is whether EPA’s decisions are arbitrary and capricious under the APA and supported by substantial evidence on the record as a whole under TSCA. How EPA’s methodology, “rife with estimates and uncertainties,” applied in practice to MC and the Industry Petitioners’ challenges must be discussed separately for acute and chronic levels of exposure. The court concludes that EPA’s results “lack epidemiological support, reflect selective use of data and failures to consider alternative acceptable data, and were based on unrealistic benchmark margins of error. In sum, the risk analysis did not accord with the best available science as the TSCA requires, and the results more closely approximate the precautionary principle than the statute’s ‘unreasonable risk’ standard.” In sum, according to the court, EPA’s analysis “was arbitrary and capricious, lacking substantial evidence, and contrary to law.”

Regulating “to the Extent Necessary” to Remove Unreasonable Risk

The court notes that “[a]lthough it would be sufficient to vacate the MC Rule and remand to EPA because of the Rule’s many shortcomings, we must also address the agency’s aggressive decision to largely prohibit MC’s uses, rather than approve or modestly revise the OSHA standards.” According to the court, once legally compliant standards of unreasonable risk are determined, EPA “must follow the menu of permissible regulations under the TSCA.” The court states that EPA “misconceived its ameliorative role in two ways.” First, EPA’s stated basis for declaring a near-complete prohibition, as opposed to any more modest exposure limit, was unauthorized. Second, when EPA decides whether to prohibit or restrict in a manner that substantially prevents a specific COU, TSCA requires the Agency to “‘consider, to the extent practicable, whether technically and economically feasible alternatives . . . will be reasonably available as a substitute.’”

Sierra Club’s Challenges

According to the court, EPA’s principal response to the challenges raised by Sierra Club is that the final risk management adequately protects vulnerable subpopulations. The court notes that its vacating and remanding the risk management rule vitiates EPA’s response to Sierra Club’s issues. The court concluded that Sierra Club’s petition lacks merit.

Commentary

It is difficult to overstate the enormous significance of the Fifth Circuit’s opinion — a decision that we view at Bergeson & Campbell, P.C. (B&C^®) as the most influential TSCA precedent since the Corrosion Proof Fittings case. TSCA stakeholders have been anxiously awaiting word in the MC litigation for well over a year now, and there was a general expectation that the ruling would likely be adverse to EPA’s positions in some way. B&C was a bit taken aback, however, by the opinion’s comprehensiveness — covering almost every major policy and legal question raised in the case that the TSCA program and stakeholders have grappled with over the last decade.

B&C was also surprised by and impressed with the clarity and forcefulness of those discussions. From whole chemical risk determinations, discretionary scoping authority for risk evaluations, PPE and occupational exposure assumptions, risk assessment methodologies, the meaning of “unreasonable risk” and managing those risks “to the extent necessary,” to consideration of economic consequences of regulation and reasonably available alternatives, the opinion leaves little to the imagination on where the court stands. In turn, and absent additional and different decisions in other courts, we see little opportunity for EPA to interpret this decision narrowly or otherwise ignore what we would view as broad mandate. The topics addressed in the opinion pervade the entire TSCA landscape, including both existing and new chemicals. The ripple effects are likely to manifest far beyond the now-vacated MC risk evaluation and risk management rule.

Many of these issues, for example, are at the heart of longstanding controversy over EPA’s procedural framework rule for conducting TSCA risk evaluations — also in litigation and now in the process of its third iteration. Though an updated rule has yet to be published in final, some of the proposed changes align with the Fifth Circuit’s opinion (e.g., on whole chemical risk determinations). Although the MC litigation did not directly address the 2024 framework rule, the Fifth Circuit’s opinion strongly suggests that portions of the 2024 framework are unlawful, including the 2024 rule’s stance on risk determinations and discretionary scoping authority. On other topics, like occupational exposure considerations and the meaning of “unreasonable risk,” careful review is warranted to ensure alignment. The Fifth Circuit makes clear that EPA must consider PPE use in risk evaluations as a “condition of use” and cannot defer consideration of PPE to the rulemaking phase. The Fifth Circuit also makes clear that the “unreasonable risk” determination is not a factual finding, but a legal conclusion drawn from statutory factors, and that it cannot simply be used as “a cover for whatever numerical estimates EPA generates.” While the framework rule does not define “unreasonable risk,” EPA’s discussion in the preamble bears revisiting considering the Fifth Circuit’s clear distancing from precautionary principles. While the final rule is past its estimated publication date (July 2026) according to the Unified Regulatory Agenda, EPA may now need additional time to further deliberate and refine. It is unclear whether the changes to the proposed rule are significant enough to justify an additional round of notice and comment.

The decision also raises several thorny questions for EPA to consider with respect to pending TSCA actions, including prioritization actions, risk evaluations, and risk management rules in progress but not complete. Are pending prioritization actions and proposed high-priority designations aligned with the Fifth Circuit’s guidance on “unreasonable risk”? Should EPA be reconsidering draft risk evaluation approaches and conclusions? Will those draft risk evaluations need to be reissued as revised drafts? Should EPA reopen opportunities for public comment? Are the proposed TSCA Section 6(a) rules premised on faulty risk evaluations? Are the requirements appropriately tailored to address identified risks “to the extent necessary”? Even for TSCA actions already completed — including high-priority designations and final risk determinations — EPA may wish to revisit them proactively rather than wait for future legal challenges.

Many of these same legal and policy topics are also just as relevant for new chemicals. The TSCA New Chemicals Program, for example, has long implemented a “whole chemical” approach to its determinations, making a single risk determination on intended, known, and reasonably foreseen circumstances associated with a new chemical. Should that change now? Should EPA be more open to exercising its discretion to tailor the scope of new chemical risk assessments to just those exposure scenarios supported by substantial evidence? Should EPA take a hard look at whether consent order terms are imposed only “to the extent necessary” — no more, no less — to address identified unreasonable risk in the underlying assessment, and not some hypothetical future use? We note, however, that consent orders are generally negotiated with the submitter and EPA and a submitter may agree on terms that go beyond the “extent necessary,” but should the terms that EPA initially offers be premised on the intended COU or should those terms meet the “extent necessary” requirement? The Fifth Circuit might consider EPA’s approach to regulating 80 to 90 percent of new chemical submissions based on speculative future uses — even where those chemicals are not yet on the market — to be the very essence of the “precautionary principle” that was excoriated in its MC opinion. To our knowledge, there has been only one industry challenge to a Section 5 decision — Inhance v. EPA — also in the Fifth Circuit. The East Fork decision might embolden a challenge to another Section 5 order to seek clarity on terms such as “reasonably foreseen” and “not likely,” the two key statutory terms not addressed in East Fork.

We do not know how EPA will react and respond to this landmark decision or whether any party would wish to appeal. The broader TSCA litigation landscape is also still coming into focus. A challenge on the TSCA risk management rule for chrysotile asbestos remains pending since June 2026, offering yet another potential near-term opportunity for the Fifth Circuit to repeat or expand upon its recent statutory analysis. Other courts are also likely to weigh in at some point in the future on other pending TSCA cases — potentially with the same or differing views — and there will undoubtedly be additional judicial surprises down the road. Meanwhile, on Capitol Hill, Congress continues to mull potential improvements and/or clarifications to the statutory text, including a critical extension of EPA’s fee collection authority to support continued TSCA implementation that currently expires December 11, 2026. With the judicial branch finally weighing in with its own views on what TSCA requires and how EPA should carry out its responsibilities, B&C expects this decision could become a focal point in the conversation among legislators about whether and what legislative changes to TSCA are needed.