Fifth Circuit Vacates EPA's Methylene Chloride Rule: A Landmark Decision Reshaping TSCA Section 6

Overview

On September 15, 2026, the U.S. Court of Appeals for the Fifth Circuit issued a significant decision in East Fork Enterprises, Inc. v. EPA, vacating EPA’s 2024 methylene chloride risk management rule and the underlying revised unreasonable-risk determination under Section 6 of the Toxic Substances Control Act (TSCA). The court granted the industry petitioners’ challenge, denied Sierra Club’s petition, and remanded the matter to EPA.

The opinion reaches well beyond methylene chloride. The Fifth Circuit held that EPA may not make a "whole chemical" unreasonable-risk determination, must account for personal protective equipment (PPE) where the record shows it is actually or reasonably foreseeably used, and cannot treat TSCA as a zero-risk or precautionary statute. The court also found that EPA's exposure limits lacked substantial evidence and that EPA failed to justify the breadth of its prohibitions, its treatment of economic consequences, and its assessment of feasible alternatives. Going forward, EPA must issue condition-of-use-specific risk determinations, build stronger evidentiary records on workplace conditions and contrary scientific evidence, and tailor any risk management restrictions to the extent necessary to address the specific unreasonable risks identified.

Background

Methylene chloride is used as a solvent in numerous products, such as adhesives, sealants, paint strippers, and coating removers. In 2019, EPA prohibited the use of methylene chloride for consumer paint and coating removal, and that consumer-use prohibition was not at issue in the recent case.

Pursuant to the 2016 amendments to TSCA, which required EPA to conduct risk evaluations for certain chemicals, EPA began the risk evaluation process for methylene chloride in 2017. In its June 2020 final risk evaluation for methylene chloride, EPA examined 53 conditions of use and concluded that 47 of them posed unreasonable risk to health. In 2022, however, EPA revised that determination without changing the underlying scientific analysis. The agency adopted two major policy changes: (1) EPA moved from use-specific determinations to a single “whole chemical” determination, and (2) EPA assumed that workers exposed to methylene chloride do not use PPE. EPA then relied on that revised determination to issue its 2024 rule, which prohibited 40 of the 53 conditions of use (which includes all consumer and most commercial and industrial uses of methylene chloride) and imposed stringent workplace protection requirements on the uses allowed to continue.

The Court's Key Holdings

The Fifth Circuit identified multiple independent grounds to vacate the 2024 rule.

1. The "Whole Chemical" Risk Determination Was Unlawful. TSCA Section 6(b) directs EPA to evaluate whether a chemical presents unreasonable risk "under the conditions of use," a phrase the statute references in no fewer than thirteen subsections. The court held that EPA lacked authority to issue a single "whole chemical" determination rather than separate determinations for each condition of use.
2. PPE Must Be Considered as a "Condition of Use." The court held that EPA must consider PPE as part of the conditions of use when the record indicates it is actually or reasonably foreseeably used. EPA could not assume no PPE use at the risk-evaluation stage and then treat PPE only as a later risk-management tool. The court faulted EPA for disregarding its earlier assumption that employers generally comply with OSHA requirements, finding that speculation about potential noncompliance could not substitute for record evidence.
3. TSCA’s "Unreasonable Risk" Standard Does Not Incorporate A Precautionary Principle. The court made clear that TSCA is not a zero-risk statute. Relying in part on Corrosion Proof Fittings v. EPA, the court stressed that “unreasonable risk” does not mean any non-zero risk and does not authorize EPA to apply a precautionary or lowest-possible-risk principle. The court characterized “unreasonable risk” as a legal conclusion informed by TSCA’s statutory standards, not simply the output of conservative models or uncertainty factors.
4. Exposure Limits Were Unsupported by Substantial Evidence. The court found that EPA's acute and chronic exposure limits were legally deficient because EPA relied exclusively on a single study for each, discounted contrary human epidemiological evidence without adequate justification, applied excessively conservative uncertainty factors, and failed to meaningfully respond to significant public comments challenging its methodology.
5. Risk Management Rules Must Be Tailored "To the Extent Necessary." TSCA requires EPA to impose restrictions only to the extent necessary to eliminate unreasonable risk. The court rejected EPA’s reliance on uncertainty about compliance with its newly imposed exposure limits as a basis for near-market-wide prohibitions, finding that EPA effectively shifted the burden onto regulated entities rather than demonstrating that prohibition was necessary. The court also found that EPA inadequately considered the chemical’s benefits, the economic consequences of its restrictions, and the availability of technically and economically feasible alternatives.

Implications for Future TSCA Risk Evaluations and Risk Management Rules

Condition-of-Use-Specific Determinations Are Required. EPA must issue separate unreasonable-risk determinations for each condition of use, rather than a single "whole chemical" determination going forward. Any risk evaluation that relies on a whole-chemical theory is now vulnerable to challenge, particularly where EPA uses that approach to sweep in conditions of use not independently shown to present unreasonable risk.

PPE and Existing Regulatory Standards Must Be Incorporated. The opinion also raises the bar for occupational exposure assessments. EPA will need to build a stronger record on actual workplace conditions, including PPE, engineering controls, and compliance practices, rather than assuming away existing protections. Where EPA discounts those controls, it will need substantial record support and a reasoned explanation.

Risk Evaluations Must Reflect the Full Evidentiary Record. The court’s treatment of the scientific record signals that future risk evaluations will need more transparent and balanced study selection, stronger engagement with contrary epidemiological evidence, and more meaningful responses to significant comments. EPA may no longer rely heavily on a single study or on conservative assumptions without clearly explaining why that approach reflects the best available science and supports a finding of unreasonable—not merely predictable—risk.

Risk Management Rules Must Be Strictly Tailored. EPA must tailor restrictions to the risks it has actually identified and regulate no more than necessary. Broad prohibitions will be harder to defend where less burdensome measures could address the same risk. EPA must also develop a more robust record on economic consequences and alternatives, particularly when proposing a ban or restriction that substantially prevents a specific condition of use.

The TSCA Procedural Framework Rule Will Likely Require Revision. The Fifth Circuit's holdings call into question significant portions of EPA's existing framework rule for TSCA risk evaluations, including its treatment of whole-chemical determinations and scoping discretion. Further notice-and-comment rulemaking on the framework is likely, and regulated entities should engage actively in that process.

Key Takeaways

East Fork Enterprises is arguably the most consequential TSCA decision in over thirty years. In light of the court's holdings, regulated entities should consider the following steps:

• Build strong evidentiary records during comment periods, including PPE usage data, occupational health studies, and economic analyses of feasible alternatives.
• Scrutinize proposed risk management rules to ensure restrictions are tailored to the extent necessary and supported by evidence that less restrictive alternatives were genuinely considered.
• Engage proactively with EPA on the revision of the procedural framework rule and any reopened comment periods for pending risk evaluations.