Court Vacates EPA Methylene Chloride Rule

The Fifth Circuit Court of Appeals ruled the agency failed to follow required scientific standards in its risk assessment.

Updated on Oct. 29, 2026 in Law

Court Vacates EPA Methylene Chloride Rule

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Should the EPA be required to meet stricter evidentiary standards when regulating chemical safety?

On September 15, 2026, the U.S. Court of Appeals for the Fifth Circuit vacated the EPA's 2024 methylene chloride risk management rule. The court determined the EPA's methodology was arbitrary, capricious, and lacked the substantial evidence required by law.

Why it matters

The ruling underscores the legal obligation of federal agencies to strictly adhere to the best available science when evaluating chemical risks. Failure to meet these evidentiary standards under the Toxic Substances Control Act creates significant vulnerabilities for future agency regulations.

The Fifth Circuit invalidated the 2024 rule due to inconsistent scientific methodology and lack of substantial evidence. The matter is now remanded to the EPA for further review to meet the mandates of the Toxic Substances Control Act.

The players

U.S. Court of Appeals for the Fifth Circuit

This is a federal appellate court that hears appeals from district courts within Louisiana, Mississippi, and Texas.

Environmental Protection Agency

The federal agency responsible for developing and enforcing regulations to protect human health and the natural environment.

East Fork Enterprises

The corporate entity that served as the petitioner in the legal challenge against the EPA's risk management rule.

The details

The court found the agency's risk assessment failed to align with the statutory requirements for scientific rigor. Consequently, the regulation is now void, and the agency must restart the analysis to ensure all findings are supported by robust, evidence-based data.

The EPA originally issued its methylene chloride risk management rule in 2024.
The U.S. Court of Appeals for the Fifth Circuit issued its decision on September 15, 2026.

Political Context

Opponents of the EPA's rule argue that the agency has overstepped its authority by imposing strict chemical standards without meeting the high evidentiary bars required by the Toxic Substances Control Act. This ruling provides a significant legal victory for industry groups seeking to constrain administrative rulemaking through more rigorous judicial oversight.

The vacation of this rule means the EPA cannot currently enforce the specific risk management standards set for methylene chloride in 2024. Affected parties and citizens should monitor subsequent agency actions as the EPA begins the mandated review process.

The takeaway

This case highlights the ongoing tension between administrative regulatory goals and the strict scientific documentation required by federal law. Agencies must ensure that every risk assessment is defensible under the standards of substantial evidence to survive future judicial scrutiny.