EPA finds methylene chloride poses an unreasonable risk to human health

The U.S. Environmental Protection Agency (EPA) has finalized a revision to the risk determination for methylene chloride, finding that methylene chloride, as a whole chemical substance, presents an unreasonable risk of injury to human health when evaluated under its conditions of use. The next step in the process is to develop a risk management rulemaking to identify and apply measures that will manage these risks.

Uses and Risks Associated with Methylene Chloride

Methylene chloride is a volatile chemical used as a solvent in vapor degreasing, metal cleaning, in the production of refrigerant chemicals, and as an ingredient in sealants and adhesive removers. Common consumer uses include adhesives, sealants, degreasers, cleaners and automobile products.

In its revised risk determination based on the 2020 risk evaluation, EPA found that methylene chloride presents unreasonable risk to the health of workers, occupational non-users (workers nearby but not in direct contact with this chemical), consumers and bystanders. EPA identified risks for adverse human health effects not related to cancer, including neurotoxicity and liver effects, from acute and chronic inhalation and dermal exposures to methylene chloride. EPA also identified risks for cancer from chronic inhalation and dermal exposures to methylene chloride.

EPA used the whole chemical risk determination approach for methylene chloride in part because there are benchmark exceedances for multiple conditions of use (spanning across most aspects of the chemical lifecycle from manufacturing (import), processing, commercial use, consumer use, and disposal) for health of workers, occupational non-users, consumers and bystanders, and because the health effects associated with methylene chloride exposures are severe and potentially irreversible (specifically cancer, coma, hypoxia and death).

Overall, EPA determined that 52 of the 53 conditions of use EPA evaluated drive the unreasonable risk determination. One condition of use does not drive the unreasonable risk: distribution in commerce. The revised risk determination supersedes the condition of use-specific no unreasonable risk determinations that were previously issued by order under section 6(i) of the Toxic Substances Control Act (TSCA) in the 2020 methylene chloride risk evaluation.

The revised risk determination for methylene chloride does not reflect an assumption that workers always and appropriately wear personal protective equipment (PPE), even though some facilities might be using PPE as one means to reduce workers’ exposure. This decision should not be viewed as an indication that EPA believes there is widespread non-compliance with applicable Occupational Safety and Health Administration (OSHA) standards. In fact, EPA has received public comments from industry respondents about occupational safety practices currently in use at their facilities and will consider these comments, as well as other information on use of PPE, engineering controls, and other ways industry protects its workers, as potential ways to address unreasonable risk during the risk management process. The consideration of this information will be part of the risk management process.

EPA understands there could be occupational safety protections in place at some workplace locations. However, not assuming use of PPE in its baseline exposure scenarios reflects EPA’s recognition that certain subpopulations of workers exist that may be highly exposed because:

As EPA moves forward with a risk management rulemaking for methylene chloride, the agency will strive for consistency with existing OSHA requirements or best industry practices when those measures would address the identified unreasonable risk. EPA will propose occupational safety measures in the risk management process that would meet TSCA’s statutory requirement to eliminate unreasonable risk of injury to health and the environment.

Next Steps for Methylene Chloride

EPA is now moving forward on risk management to address the unreasonable risk presented by methylene chloride. Note that in taking this action, EPA has not conducted a new scientific analysis on this chemical and the risk evaluation continues to characterize risks associated with individual conditions of use in the risk evaluation of methylene chloride in order to inform risk management.

In June 2021, EPA announced a path forward for the first 10 chemicals to undergo risk evaluation under TSCA to ensure the public is protected from unreasonable risks from these chemicals in a way that is supported by science and the law. The revised risk determination for methylene chloride was developed in accordance with these policy changes, as well as the Biden-Harris Administration’s Executive Orders and other directives, including those on environmental justice, scientific integrity, and regulatory review. EPA’s revisions ensure that the methylene chloride risk determination better aligns with the objectives of protecting health and the environment under the amended TSCA.

Separately, EPA is conducting a screening-level approach to assess potential risks from the air and water pathways for several of the first 10 chemicals, including methylene chloride. The goal of the screening approach is to evaluate the surface water, drinking water, and ambient air pathways for methylene chloride that were excluded from the 2020 risk evaluation, and to identify if there are risks that were unaccounted for in that risk evaluation. EPA expects to describe its findings regarding the chemical-specific application of this screening-level approach in its proposed risk management rule for methylene chloride.

Additionally, EPA expects to focus its risk management action on the conditions of use that drive the unreasonable risk. However, EPA is not limited to regulating the specific activities found to drive unreasonable risk, and may select from among a wide range of risk management requirements. As a general example, EPA may regulate upstream activities (e.g., processing, distribution in commerce) to address downstream activities (e.g., consumer uses) driving unreasonable risk, even if the upstream activities do not drive the unreasonable risk.

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