Background
Methylene chloride is a solvent used in products and industrial processes including adhesives, paint and coating removal, furniture refinishing, refrigerant production, and battery manufacturing. Although overexposure can cause serious injury or death and the chemical has carcinogenic properties, it has been used for decades under workplace-safety requirements, including Occupational Safety and Health Administration exposure limits.
Acting under the Toxic Substances Control Act, EPA determined that methylene chloride presented an unreasonable risk as a “whole chemical.” Its 2024 rule prohibited 40 of 53 conditions of use and subjected 13 remaining uses to a workplace-protection program with exposure limits of 16 parts per million over 15 minutes and 2 parts per million over eight hours. Industry petitioners challenged the rule and its underlying risk determination, while the Sierra Club separately argued that EPA had not adequately protected fenceline communities, genetically susceptible people, and people allegedly exposed to ozone-depletion risks.
The Court’s Holding
The Fifth Circuit granted the industry petition, vacated the methylene chloride rule and associated risk determination, and remanded to EPA. The court held that TSCA requires EPA to determine unreasonable risk separately for each condition of use and does not authorize a “whole chemical” determination. It also held that EPA unlawfully and without substantial evidence assumed workers did not use personal protective equipment, despite evidence of PPE use and OSHA requirements.
The court further held that EPA’s acute and chronic exposure limits were unsupported by substantial evidence and were arbitrary and capricious. In the court’s view, EPA relied selectively on conservative assumptions and limited animal or human studies while inadequately addressing contrary human epidemiological evidence, existing OSHA limits, and significant public comments. The court also concluded that EPA had not shown its near-total prohibition was necessary to eliminate unreasonable risk and had inadequately considered the economic consequences and availability of technically and economically feasible alternatives.
The court denied the Sierra Club’s petition. It held that EPA could exclude exposure pathways it lacked a sufficiently developed scientific methodology to assess, that EPA reasonably accounted for genetically susceptible people through a conservative population estimate, and that the Sierra Club lacked standing to pursue its ozone-depletion theory because the asserted chain of injury was too speculative.
Key Takeaways
- TSCA requires EPA to evaluate unreasonable risk by individual condition of use rather than treating a chemical as presenting unreasonable risk “as a whole.”
- EPA must account for actual or reasonably foreseeable PPE use when evaluating workplace exposure and may not assume noncompliance without supporting evidence.
- TSCA is not a zero-risk statute, and restrictions must go only as far as necessary to eliminate unreasonable risk.
- EPA must address contrary scientific evidence, significant comments, economic consequences, and feasible substitutes before imposing sweeping prohibitions.
Why It Matters
The decision eliminates EPA’s 2024 methylene chloride restrictions unless and until the agency adopts a new rule consistent with TSCA. On remand, EPA must conduct use-specific risk determinations, account for relevant workplace protections, support any exposure limits with the record as a whole, and justify its chosen restrictions as necessary to address unreasonable risk.
More broadly, the opinion applies demanding judicial scrutiny to EPA’s scientific and policy judgments under TSCA. It signals that courts will distinguish statutory “unreasonable risk” from a precautionary or zero-risk approach and will require EPA to substantiate both its risk findings and the scope of its remedies.