The U.S. Court of Appeals for the Fifth Circuit vacated a U.S. Environmental Protection Agency rule last week that banned most uses of methylene chloride, an industrial solvent often used as a paint stripper.  

EPA ignored studies that showed methylene chloride didn’t cause significant adverse health effects and failed to account for the use of personal protective equipment by workers who were exposed to the substance, wrote Judge Edith Jones in a 44-page opinion.

The agency also used the smallest temporary impacts on certain body functions and then applied inflated benchmark exposure measures, according to the Fifth Circuit ruling.

“In addition to finding exaggerated unreasonable risk for the conditions of use, the agency applied the (legally unauthorized) ‘whole chemical’ risk determination to regulate every use of MC and ignored widespread PPE use, the judge wrote. “The results are unsurprising. EPA’s ultimate exposure limits are approximately ten times smaller than those that OSHA has enforced for 25 years.”

The American Chemistry Council issued a statement following the ruling, saying it reinforces that decisions under the Toxic Substances Control Act, or TSCA, must be based on scientific evidence and real-world conditions.

“For years, ACC has maintained that TSCA requires EPA to evaluate and manage risk based on individual conditions of use and the best available science, including consideration of existing workplace protections and real-world exposure information,” said the industry group in a news release. “The court agreed, rejecting EPA’s improper ‘whole chemical’ approach and affirming that risk determinations must consider individual conditions of use, including proven workplace protections such as personal protective equipment."

The court also highlighted the need for EPA’s risk-management approach to consider current OSHA standards and exposure limits as well as the economic consequences of restrictions, ACC noted.

"The ruling makes clear that TSCA is designed to manage unreasonable risk through targeted, evidence-based regulation and is not a zero-risk statute,” ACC stated. 

However, an environmental health advocacy group called Toxic-Free Future said the ruling comes at the expense of public health, putting people exposed to the chemical at risk of cancer and possible death from acute exposure.

We have known for decades that methylene chloride exposures can cause cancer, neurological and liver effects, and can be deadly for consumers and workers,” said Liz Hitchcock, director of federal policy at Toxic-Free Future.

“Congress updated TSCA in 2016 so that EPA could finally take action to get dangerous chemicals like methylene chloride out of our homes and workplaces. Mothers whose sons lost their lives due to this chemical fought hard for a ban on this notoriously deadly substance.”

In 2024, the Biden-led EPA finalized a ban on most uses of methylene chloride under TSCA.

The regulation called for phasing out consumer uses of methylene chloride within a year and most industrial and commercial uses within two years.

At the time, the agency’s announcement included several statements of support, including one from a woman whose son died in 2017 after exposure to the substance.

The Fifth Circuit decision that EPA lacked authority to issue a new whole-chemical revised risk determination for methylene chloride  could have broader implications for other chemical reviews under TSCA, wrote attorneys from Sidley Austin LLP on the firm’s website.

“Under the approach the EPA adopted beginning in 2021, a whole-chemical unreasonable-risk determination could subject uses to risk management even where the agency’s underlying scientific analysis did not independently find unreasonable risk from that particular use,” the attorneys wrote. “The Fifth Circuit rejected that approach and held that activities involving a chemical may present different levels of risk and must be evaluated accordingly.”

In the future, courts reviewing TSCA rules for other chemicals may disagree with the Fifth Circuit’s reasoning, leading to a “substantial litigation risk for the EPA’s post-2016 approach,” the Sidley Austin legal experts stated.