A federal appeals court has vacated EPA’s 2024 methylene chloride rule and its supporting risk determination, raising wider questions about how chemical risks are evaluated under TSCA. The decision focuses on specific uses, workplace protections, scientific evidence, and proportionate restrictions. For businesses, regulatory uncertainty is not a reason to step back from chemical safety. It is a reason to understand affected uses, strengthen exposure data, and verify applicable obligations before changing compliance plans.
A court can change the regulatory outlook without changing a chemical’s hazards. For businesses navigating U.S. chemical requirements, the latest methylene chloride decision is a reminder that effective compliance depends on both legal clarity and sound scientific evidence.
On September 15, 2026, the U.S. Court of Appeals for the Fifth Circuit unanimously vacated, or set aside, the U.S. Environmental Protection Agency’s (EPA) 2024 methylene chloride risk management rule and its supporting “whole chemical” unreasonable-risk determination. The court remanded the matter, sending it back to EPA for further proceedings.
Methylene chloride, also called dichloromethane or DCM, is a volatile solvent used in applications such as metal cleaning, adhesives, and chemical manufacturing. EPA had previously identified serious health risks associated with exposure, including effects on the nervous system and cancer. Importantly, the court ruling addressed how EPA evaluated and regulated those risks, but it did not establish that the chemical is safe.
The Toxic Substances Control Act (TSCA) separates risk evaluation (determining whether unreasonable risk exists) from risk management (deciding how to address it). EPA’s 2024 rule prohibited all consumer uses and most industrial and commercial uses of methylene chloride, while allowing certain uses to continue under a Workplace Chemical Protection Program. That program included exposure limits, monitoring, and protective measures. The court found legal and evidentiary shortcomings in the basis for EPA’s action, with potential implications beyond this one solvent.
Five key takeaways from the court’s ruling
- Rejection of the “whole chemical” approach
The court held that TSCA requires a separate unreasonable-risk determination for each condition of use, rather than one determination for a chemical as a whole.
“Conditions of use” describe the circumstances in which a substance is manufactured, processed, distributed, used, or disposed of. EPA’s 2022 revised determination assessed methylene chloride as a whole chemical; the court rejected that approach. For businesses, the distinction matters because exposure can differ substantially between activities. Knowing that a substance is present is only the starting point, but understanding how it is used is essential.
- PPE must be considered in worker-risk assessments
The court rejected EPA’s approach to assuming non-use of personal protective equipment (PPE) when determining worker risk. EPA’s published explanation states that its 2022 revision did not assume all exposed workers were always provided with, or appropriately wore, PPE, and that it considered protective measures during risk management. The court nevertheless found that actual PPE use had to be accounted for in the risk determination. This is not a finding that PPE eliminates risk or that meeting Occupational Safety and Health Administration (OSHA) requirements automatically resolves every TSCA concern. It reinforces the importance of reliable evidence about workplace conditions and the effectiveness of controls in risk determination.
- “Unreasonable risk” does not mean “zero risk”
The court distinguished TSCA’s “unreasonable risk” standard from a requirement to eliminate every possible risk. It also emphasized that restrictions must go no further than necessary to address the unreasonable risk identified. This does not diminish the seriousness of methylene chloride’s hazards. It requires a defensible connection between the evidence, the risk conclusion, and the regulatory response.
For readers outside the regulatory field, the distinction is straightforward: a substance’s capacity to cause harm (e.g., associated hazards) is not the same as the risk arising from a particular exposure.
- Greater scrutiny of EPA’s scientific analyses
The court scrutinized EPA’s interpretation of scientific studies and the assumptions supporting its exposure limits. EPA’s own overview explains that TSCA risk evaluations must consider both hazard and exposure, use the best available science, and base decisions on the weight of scientific evidence. The issue is not whether uncertainty can be considered, but whether the methods and assumptions used to address it are adequately justified.
Among other concerns, the court questioned EPA’s:
- Selection and treatment of human and animal studies
- Application of uncertainty factors to account for limitations in the available data
- Treatment of PPE in exposure assessments
- Development of exposure limits and related controls
For businesses, the practical message is to strengthen the evidence: reliable information on uses, exposure, and control measures can support better regulatory engagement and more informed internal decisions.
- Economic impacts and alternatives matter
The court also questioned EPA’s consideration of economic consequences and technically and economically feasible alternatives when developing restrictions. An important boundary remains: TSCA risk evaluations exclude costs and other non-risk factors. Economic consequences and alternatives belong at the risk management stage, when EPA selects measures to address the identified risk. Businesses should therefore distinguish evidence about whether a risk exists from evidence about how that risk can be managed effectively.
Why this matters beyond methylene chloride
H2 Compliance’s earlier analysis highlighted the potential for changes to the whole-chemical approach, PPE assumptions, and treatment of real-world uses. The court’s decision brings several of those issues into sharper focus. EPA had also proposed changes to its risk evaluation framework in September 2025; a proposal, however, should not be confused with a final regulatory change.
The ruling could influence other TSCA evaluations, rulemakings, and legal challenges, particularly where they rely on similar reasoning. Possible consequences include:
- Delays in TSCA risk-management actions
- Reevaluation of existing risk evaluations
- Greater consideration of workplace controls and PPE
- Expanded opportunities to challenge EPA rules
- Continued regulatory uncertainty while EPA determines its next steps
These outcomes are possibilities, not automatic consequences. The decision does not itself invalidate rules for other chemicals. Each action has its own scientific record and legal status, and wider effects will depend on EPA’s response and subsequent court proceedings.
What this means for businesses
For manufacturers, importers, processors, formulators, and downstream users, the priority is to separate the court’s findings from assumptions about immediate compliance relief. EPA’s methylene chloride webpage still describes the 2024 rule and does not resolve the procedural effect of the September 2026 decision.
Before changing compliance arrangements, businesses should verify the court’s mandate, any stay or further review, and EPA’s implementation position. Practical priorities are to:
- Map affected uses: Identify relevant substances, activities, and supply-chain roles.
- Strengthen supporting data: Document exposure conditions and the implementation of workplace controls.
- Track verified changes: Review official developments before adjusting deadlines, sourcing, or compliance plans.
Do not assume all methylene chloride obligations have ended. EPA separately identifies its 2019 restrictions on consumer paint and coating removal. Other applicable workplace safety and chemical management requirements must also be considered. A change to one TSCA rule is not a general exemption from protecting workers or managing chemical risks.
The leadership opportunity is to move beyond reactive deadline management. Businesses that understand their chemical uses, maintain credible exposure data, and connect regulatory decisions with product stewardship will be better placed to adapt, without losing sight of worker protection or business continuity.
How H2 Compliance can help
H2 Compliance combines regulatory expertise and scientific support to help businesses respond to evolving chemical requirements. Relevant services include:
- Regulatory tracking: Monitor changing requirements and business implications.
- Toxicology and risk assessment: Evaluate hazards, exposure, and chemical risks.
- Occupational exposure: Support exposure banding and industrial hygiene assessments.
- Regulatory strategy: Plan compliance activities and market access pathways.
- Hazard communication: Prepare and update safety data sheets and labels.
- Product stewardship: Strengthen chemical management across the product life cycle.
Published November 2nd, 2026
Article image generated with the assistance of Artificial Intelligence.