Methylene Chloride: A Case Study of the Rocky Road to Restricting Hazardous Chemicals in Commerce
by Ted Schettler, science director
Methylene chloride is a volatile liquid used as a solvent in metal cleaning, chemical production, and aerosols. It is an ingredient in sealants, adhesive removers, auto products, and paint strippers, many of which have historically been directly available to consumers.
The chemical is toxic to the nervous system. Acute exposure to fumes can cause dizziness, headache, confusion, loss of consciousness, respiratory failure, and death. In addition to direct toxicity to neurons, it is metabolized to carbon monoxide, depriving the brain and heart of oxygen and increasing the risk of death. Chronic exposures can cause kidney and liver damage, cognitive impairment and cancer.
Methylene chloride is particularly dangerous when used in confined spaces with inadequate ventilation or respiratory protection. Dozens of deaths are attributed to inhalation exposures in the workplace and among people who bought paint strippers with methylene chloride for do-it-yourself home projects, unaware of the hazards. For years, surviving family members joined environmental public health groups pushing for restrictions or bans on many uses and widespread availability of the chemical.
The Toxic Substances Control Act (TSCA) and Its Revisions
Most chemicals in the United States that are not pharmaceuticals or pesticides are regulated by the US EPA under the Toxic Substances Control Act (TSCA). First adopted in 1976, TSCA was ineffective in controlling production and use of even highly hazardous chemicals. It required the EPA not only to find that a chemical posed an “unreasonable risk” when proposing to restrict its use but also to select the “least burdensome alternative” among the options to reduce the risk. This meant finding a solution where the benefits of restrictions or a ban outweighed the costs, and left large loopholes for claims that modifying manufacturing or production processes would be too expensive. Moreover, TSCA grandfathered thousands of chemicals in use at the time, making it virtually impossible to restrict their continued use, though many were known to be dangerous. Infamously, the original TSCA left the EPA unable to restrict asbestos, a known carcinogen that had already claimed thousands of lives.
After years of prolonged advocacy efforts and contentious debates, a revised TSCA was passed into law in 2016. Known as the Frank R. Lautenberg Chemical Safety for the 21st Century Act, it significantly overhauled the original TSCA by requiring 1) mandatory evaluation of existing chemicals already in commerce, 2) risk-based safety assessments, accounting for susceptible sub-populations—including pregnant women, children, and workers—without considering costs during the risk evaluation process, 3) an affirmative safety declaration for a new chemical proposed for production and use, finding that it posed no unreasonable risk, or requiring restrictions, 4) enforceable deadlines for EPA to conduct risk evaluations and take regulatory actions. Methylene chloride was among the first ten existing chemicals selected for risk evaluation, to be followed by risk management, under the revised law.
Methylene Chloride Rule Making Under TSCA; Court Challenge
In 2017 (Obama administration), EPA proposed a ban on methylene chloride in paint and coating removal and finalized a rule in 2019 banning consumer sales and use of the solvent for these purposes. Despite known deaths from workplace exposures, commercial and industrial uses were not restricted at that time. Challenges to this rule were rejected by the Second Circuit court in 2021.
In 2020 (first Trump administration), the EPA issued a final risk determination finding that 47 of 53 conditions of use for the chemical posed unreasonable health risks. In 2022 (Biden administration) the EPA found that methylene chloride, as a “whole chemical,” presented unreasonable risks to health. As part of the justification for that approach, the agency noted that workers who use or are exposed to the chemical do not necessarily wear or have access to personal protective equipment (PPE) that would protect them from inhaling the fumes or skin contact at unsafe levels. Thus, the finding of unreasonable risk was broad and applied to most all uses, justifying the whole chemical approach rather than evaluating and managing risks associated with each condition of use. In 2023 (Biden administration), the EPA proposed a comprehensive risk management rule that would ban nearly all remaining consumer, commercial, and industrial uses and finalized the rule in 2024, setting tight exposure limits for the few remaining uses.
The American Chemistry Council along with East Fork Enterprises and Epic Paint sued the EPA to challenge that rule, arguing that EPA exceeded its authority, and that EPA’s conclusions are arbitrary and capricious and unsupported by substantial evidence. The Sierra Club also challenged the rule for different reasons, arguing that the rule does not go far enough to eliminate unreasonable risks because it fails to adequately address risks to 1) fenceline communities, 2) people who are genetically more susceptible to cancer, and 3) to the environment and people who live at high elevation and are subject to ozone depletion.
On September 15, 2026, the U.S. Court of Appeals for the Fifth Circuit unanimously vacated the EPA’s 2024 risk management rule for methylene chloride and the agency’s 2022 “unreasonable-risk” determination. The court found that the agency had overstepped its authority as provided in the 2016 revisions to TSCA and sent the risk evaluation and management plan back to the EPA for review. The court said that the risk evaluation and risk management plans must be developed for each use of the chemical under specific conditions of use and could not be adopted for the chemical as a whole. According to the court, use of PPE is a “condition of use” and would adequately protect workers from unreasonable risk. Moreover, the court found that EPA’s determination of permissible exposure levels to methylene chloride were far lower than could be justified by existing scientific information and criticized their methods for arriving at them, saying that they ignored some studies in favor of others. And, while economic considerations may not be considered during risk evaluations under the revised TSCA, they must be considered when deciding among risk management options. The court found that the “agency repeatedly ignored tackling the economic feasibility of alternative chemicals or processes. EPA did not account for much higher costs and lower productivity, in addition to adverse environmental consequences, associated with the adoption of alternatives to MC.”
The court discussed at some length the meaning of “unreasonable” risk and to regulate “to the extent necessary” to eliminate such risks. The court said, “Congress did not enact TSCA as a zero-risk statute” and “unreasonable risk does not incorporate any precautionary principle.” Citing the Merriam-Webster Dictionary the ruling said, “The TSCA’s text does not authorize anything like a precautionary or lowest possible risk principle. The word ‘unreasonable’ means something that ‘exceed[s] the bounds of reason, appropriateness, or moderation.’”
The court also denied the Sierra Club’s petition saying that the EPA does not have a reliable method to estimate risks to fenceline communities and that an “elevated” risk is not the same as an “unreasonable” risk. With respect to their argument that some people are genetically more susceptible to cancer, the court held that EPA’s analysis that is intended to protect 95 percent of people would include those who are genetically susceptible. Finally, regarding environmental impacts and ozone depletion, the court found that the Sierra Club lacked standing because the causal chain between methylene chloride releases and resulting cancer in a Sierra Club member was too speculative. Moreover, the agency does not consider the chemical to be an ozone depleting agent.
Next Steps
Now the EPA will be required to conduct risk evaluations for each use of the chemical and develop risk management plans for any uses that pose an unreasonable risk to health in those specific circumstances. The agency will be unable to assume the absence of PPE use in the workplace when evaluating risks. Meanwhile the ban on methylene chloride in consumer paint and coating removers remains in effect.
After TSCA was amended in 2016, the EPA prioritized ten existing chemicals, including methylene chloride, for risk evaluation and risk management decisions from among the thousands in commerce. All risk evaluations have been completed for the ten chemicals. Risk management plans have been proposed for several, some of which are now the subject of litigation. The methylene chloride decision by the Fifth Circuit Court of Appeals is the first time that a court has rejected a risk management plan adopted by the EPA and sent it back for review under the new TSCA.
Although it remains to be seen, this court ruling could have significant limiting effects on the effectiveness of the revised TSCA for protecting worker and public environmental health. It will certainly shape the debate about what represents an “unreasonable risk” and the assumptions that go into that determination. Risk management proposals will undergo more cost-benefit and cost-effectiveness scrutiny. It is easy to see how political and policy biases will frame those decisions with lasting impacts. We will continue to see additional court challenges to interpretations of other aspects of the revised TSCA in agency risk evaluations and management plans in process, and in the future.
Stepping back and looking at the larger context, in the ten years since TSCA was amended, little has been accomplished to address the potential risks associated with the thousands of additional chemicals already in commerce. Ten years…ten chemicals…litigation. An additional 30 chemicals have been prioritized for evaluation since 2019 but none has been completed. A snail’s pace while workers, fenceline communities, and consumers continue to be exposed and many experience adverse health effects every day.