On September 15, 2026, the US Court of Appeals for the Fifth Circuit vacated the US Environmental Protection Agency’s (EPA’s) risk management rule for methylene chloride, a widely used solvent, under the Toxic Substances Control Act (TSCA). East Fork Enterprises, Inc. v. EPA, Nos. 24-60227 & 24-60256 (5th Cir. 2026). The rule prohibited 40 uses of methylene chloride and imposed numerous workplace requirements on the remaining 13 industrial and commercial uses, including exposure monitoring and an existing chemical exposure limit roughly ten times more stringent than OSHA’s standards. After a ten-year process of EPA evaluating extensive data on methylene chloride, publishing and then revising a determination that the substance presents an unreasonable risk to human health, and imposing bans on a majority of uses of the substance, including industrial uses and uses in finished products, the Fifth Circuit scrapped the rule, finding EPA exceeded its statutory authority and lacked sufficient evidence to support its rule.

This landmark case is the first time a federal court has substantively interpreted TSCA Section 6 chemical risk evaluation and risk management provisions since Congress overhauled the statute in 2016. The court interpreted key parts of statute, including how EPA must evaluate and regulate existing chemicals, what the “unreasonable risk” safety standard requires, how restrictions on uses of a chemical must be tailored to mitigate the identified risks, and what evidentiary burden EPA must meet. The court also clarified EPA’s role in evaluating worker exposures when there are existing OSHA standards in place for the same chemical and criticized the methods by which EPA concluded that OSHA regulations were insufficient. These issues have been debated and interpreted for almost a decade by EPA (in multiple administrations), stakeholders, and legal practitioners. While this decision is binding precedent only in the Fifth Circuit’s jurisdiction, it certainly can serve to inform future EPA actions and other federal circuit courts that are considering similar TSCA risk management rules.

This decision has implications for not only the methylene chloride regulation but also EPA’s other final TSCA risk management rules, chemicals currently in the risk management rulemaking process, and chemicals further back in the risk evaluation pipeline. The decision could even have implications for EPA’s new chemicals program. Companies that manufacture chemicals or products that use chemicals being reviewed under the TSCA program should pay attention to how EPA chooses to implement the Fifth Circuit’s ruling in its policies and rulemakings moving forward. OSHA regulated employers should do the same, with a focus on whether EPA follows the constraints imposed on the agency by this ruling in its pending and future efforts to regulate workplace chemical exposure.    

TSCA Risk Evaluations and Risk Management Rules

EPA’s TSCA chemical risk evaluations and risk management regulations can impact everyone in the chemical’s supply chain, including manufacturers of the chemicals, importers, processors, distributors, and, importantly, users of these chemicals in all types of downstream products and applications. When EPA finds that certain uses of the chemical present an unreasonable risk, these uses can face potential restrictions such as bans, labeling, concentration limits, recordkeeping, downstream notification, and requirements for how the substance can be used. Conversely, when EPA finds that a use of a chemical is safe, the finding will preempt state actions for the same use of the chemical, creating national consistency rather than a patchwork of differing state rules. Thus, the Fifth Circuit’s decision could have broad impacts because it defines what is required of EPA in making TSCA risk determinations and risk management rules.

Key Legal Interpretations of TSCA

In the decision, the Fifth Circuit made the following interpretations of TSCA:

TSCA requires that EPA make separate risk determinations for each use of the chemical it evaluates. TSCA directs EPA to determine whether the manufacture, processing, distribution, use, or disposal of a substance presents an unreasonable risk under the substance’s conditions of use. The prior administration had interpreted this requirement to mean EPA must make a single determination that a substance “as a whole” presents or does not present an unreasonable risk, even though EPA evaluates specific uses of a substance, and not every use of the substance presents a risk.

Since EPA enacted the “whole chemical” policy, this has led to more conservative and arbitrary determinations for chemicals under review. EPA has found that every chemical it has reviewed presented an unreasonable risk, even if only a few or even one condition of use out of many was the driver of that risk finding. This approach has been widely criticized as not authorized by statute, vague, unscientific, confusing to stakeholders, and artificially forcing every condition of use, even safe uses, into the risk management stage where they can be (and have been) regulated by EPA.

In the methylene chloride rule, EPA had revised the risk determination to adopt the “whole chemical approach.” The court found this approach was unlawful because TSCA requires separate risk determinations for each condition of use (each “activity” concerning the chemical). The court reasoned that this interpretation is consistent with the statute’s multiple references to evaluating conditions of use and preemption of state law with respect to condition of use. Further, EPA’s own procedural regulations for risk evaluations at the time the methylene chloride rule was evaluated required separate risk determinations.

EPA cannot assume that personal protective equipment (PPE) is not routinely worn by workers in the workplace. Under the prior administration, EPA revised its risk determinations, including for methylene chloride, to remove the assumption that PPE was used by workers who handle methylene chloride in the workplace. Similar to the whole chemical approach, this policy resulted in more conservative findings of risk. Uses of a chemical EPA originally found to be safe when PPE protections are used were now deemed presenting an unreasonable risk and subject to further regulation. EPA’s reasoning was that it cannot assume all workers wear PPE, thus, to be protective, it must evaluate exposures to workers of methylene chloride as if they are not wearing PPE such as respirators. However, the court found that this approach violated TSCA because TSCA requires EPA account for PPE if it is part of the chemical’s conditions of use (circumstances in which the substance is known, intended, or reasonably foreseen to be used), and PPE is a significant condition of use of methylene chloride. Further, the court found that EPA lacked evidence that workers do not use PPE.

“Unreasonable risk” does not mean zero risk. The court found that EPA took a far more conservative view of what unreasonable risk entails than TSCA intended. In applying Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024), the court independently evaluated whether EPA’s methodology for benchmarking risk in the risk evaluation for methylene chloride was appropriate. The court found EPA’s approach to establishing chemical exposure limits for methylene chloride to be “rife with uncertainties,” lacking in scientific support, failing to consider relevant data, and based on unrealistic benchmark margins of error. The court made clear that unreasonable risk does not mean zero risk, nor does it incorporate any precautionary principle.

TSCA requires EPA to support its findings with substantial evidence in the rulemaking record taken as a whole. The court discussed how this TSCA-specific evidentiary standard is more rigorous than the typical Administrative Procedure Act (APA) “substantial evidence” standard. The TSCA standard requires that EPA base its decision on the entire record, including taking into account whatever in the record detracts from the weight of the agency’s decision, and the decision has to be “what a reasonable mind might accept as adequate” to support the decision.

In applying this standard, the court found that several aspects of EPA’s rule lacked support by substantial evidence in the record taken as a whole. The rule had imposed an eight-hour exposure limit of two parts per million (ppm) and a 15-minute limit of 16 ppm. By comparison, the OSHA methylene chloride standard establishes an eight-hour limit of 25 ppm and a 15-minute limit of 125 ppm. The court found that: (1) EPA’s acute workplace exposure limit was unsupported because EPA based the limits on only one study and discounted contrary, more relevant, and comprehensive data. EPA also disregarded data showing worker deaths at significantly higher concentrations than the exposure limits being proposed, and EPA disregarded the current OSHA standard for methylene chloride; (2) EPA’s chronic exposure limit was unsupported because it relied on one flawed study, ignored relevant evidence that was contrary to its conclusions, inappropriately applied uncertainty factors, failed to respond to significant scientific input, and improperly assumed studies showing increased bilirubin in blood were indicative of liver disease; and (3) EPA assumed workers exposed to methylene chloride did not use PPE, contrary to OSHA standards and disregarding widespread PPE use. The court found that EPA’s expressed concerns that some employees might fall outside OSHA coverage or that some employers might fail to comply did not justify disregarding the agency’s earlier findings about workplace practices. This court found that EPA’s argument that employers were noncompliant was not supported by the data on which EPA claimed to rely.   

TSCA only authorizes EPA to regulate a chemical “to the extent necessary” to mitigate the risk, and no more. TSCA requires EPA to regulate a chemical only “to the extent necessary” so that the chemical no longer presents unreasonable risk and to consider the benefits of the chemical, economic impacts, and the availability of technically and economically feasible alternatives. The court found that EPA failed to do so in the methylene chloride rule. EPA adopted a near-complete prohibition as a first resort because it was uncertain whether companies could comply with the proposed chemical exposure limits. The court held that this approach was unlawful because it shifts the burden on regulated entities to prove they can comply with the standard rather than EPA satisfying its burden to demonstrate it was restricting the chemical only to the extent necessary to address the identified risks. The court also found that EPA failed to adequately assess the availability of technically and economically feasible alternatives and ignored the economic feasibility of substitutes, including higher costs, lower productivity, and adverse environmental consequences.

EPA was justified in excluding air and water exposure pathways in its evaluation of methylene chloride. An environmental group petitioner challenged that EPA failed to consider “fenceline communities” who are exposed to methylene chloride through water and air surrounding the facility. While the court did not interpret TSCA’s provisions for scoping of risk evaluations, the court did say a “fair reading” of TSCA leaves “ample latitude” for EPA to exclude exposure pathways when science or methodology is not developed.

What Happens Next?

Companies that manufacture, import, process, distribute, or use chemicals (or products containing these chemicals) currently in the queue for review under the TSCA program should pay attention to how EPA approaches the Fifth Circuit’s ruling. EPA has a robust set of chemicals in its pipeline that are either undergoing or have completed risk evaluations and risk management rules, as shown below:  

EPA will have to decide in the coming months whether and how to review its existing chemicals program work over the last ten years for consistency with the Fifth Circuit’s interpretations of TSCA.

For example, EPA removed the assumption that PPE is used by workers and has used the “whole chemical” approach in every risk determination published. This has resulted in every chemical being found to present an unreasonable risk and having all conditions of use go to risk management. EPA has to decide whether it wants to revise every risk determination for already published risk determinations and/or to implement the use-by-use determination approach and incorporation of PPE considerations in future risk determinations.

For risk evaluations, EPA will have to decide whether to apply the Fifth Circuit’s interpretation of the heightened substantial evidence standard and reevaluate the evidence it relies on to support its risk evaluations. This would involve an evaluation of the relevance and validity of the studies it used and whether it has properly considered other studies in the record that may have differing results. This also involves evaluating whether EPA has used inflated margins of exposure or uncertainty factors and whether its assumptions and methodologies are scientifically defensible. EPA will have to ensure it has a substantial record to support its scientific conclusions. EPA will also have to evaluate if it properly considered current OSHA standards and existing workplace controls for the same chemical. Significantly, EPA will evaluate whether it has sufficient evidence in the record to support findings such as PPE usage rather than relying on unsupported assumptions.

EPA could also apply this heightened evidentiary scrutiny to its decisions for new chemicals because the same “unreasonable risk” standard applies to EPA’s review of new chemicals.  

Finally, for risk management rules, EPA will have to decide if it wants to issue revised rules and/or re-evaluate the draft risk management rules to ensure that each rule is sufficiently narrowly tailored to restrict the chemical only to the extent necessary to mitigate the identified risk, rather than banning a substance first and asking for data demonstrating compliance with anything less than a ban.

Additionally, EPA is set to publish a final procedural regulation for chemical risk evaluations. EPA will have to decide whether and if it wants to revise or supplement the rule with the Fifth Circuit’s interpretations of TSCA. This regulation will likely be the first opportunity for EPA to demonstrate whether and how it intends to incorporate the Fifth Circuit ruling.

The decision also raises questions about the role of EPA versus OSHA in setting exposure limits and workplace standards for worker exposures to chemicals. The court reinforced that EPA cannot arbitrarily deviate from existing OSHA standards or disregard real-world worker safety practices if the data does not support it (as it did not here). EPA must coordinate with OSHA in its development of workplace safety rules, as is already required under TSCA Section 9.

All of these considerations are further complicated by agency resource constraints, statutory deadlines for risk evaluations and risk management rules that have been missed, and only two years left of the current administration to implement changes.

Companies regulated by TSCA should pay close attention to how EPA addresses its risk evaluations and risk management rules in its own policies and in the courts. The court decision also highlights the significance of providing data and input to EPA during the rulemaking process, early and often. This includes exposure data, information on real-world workplace practices using the chemical, and scientific studies. EPA has to ensure it has a robust administrative record to support its risk findings and that it properly considers the entire record as a whole.