EPA Finds Methylene Chloride, as a Whole Chemical Substance, Presents an Unreasonable Risk to Human Health

The U.S. Environmental Protection Agency (EPA) announced on November 10, 2022, the availability of the final revision to the risk determination for the methylene chloride risk evaluation issued under the Toxic Substances Control Act (TSCA). 87 Fed .Reg. 67901. EPA states that the revision to the methylene chloride risk determination reflects its announced policy changes to ensure the public is protected from unreasonable risks from chemicals in a way that is supported by science and the law. EPA determined that methylene chloride, as a whole chemical substance, presents an unreasonable risk of injury to health when evaluated under its conditions of use (COU).

In its November 10, 2022, press release, EPA states that methylene chloride is a volatile chemical used as a solvent in vapor degreasing, in metal cleaning, in the production of refrigerant chemicals, and as an ingredient in sealants and adhesive removers. According to EPA, common consumer uses include adhesives, sealants, degreasers, cleaners, and automobile products.

In its revised risk determination, EPA found that methylene chloride presents unreasonable risk to the health of workers, occupational non-users (ONU) (workers nearby but not in direct contact with this chemical), consumers, and bystanders. EPA states that it 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 states that it used the whole chemical risk determination approach for methylene chloride in part because there are benchmark exceedances for multiple COUs (spanning across most aspects of the chemical lifecycle from manufacturing (import), processing, commercial use, consumer use, and disposal) for health of workers, ONUs, consumers, and bystanders, and because the health effects associated with methylene chloride exposures are severe and potentially irreversible (specifically cancer, coma, hypoxia, and death).

EPA determined that 52 of the 53 COUs evaluated drive the unreasonable risk determination. One COU does not drive the unreasonable risk: distribution in commerce. The revised risk determination supersedes the COU-specific no unreasonable risk determinations that were previously issued by order under TSCA Section 6(i) in the 2020 methylene chloride risk evaluation.

EPA notes that 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. EPA states that this decision should not be viewed as an indication that it believes there is widespread non-compliance with applicable Occupational Safety and Health Administration (OSHA) standards. In fact, according to EPA, it 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 acknowledges that there could be occupational safety protections in place at some workplace locations. Not assuming use of PPE in its baseline exposure scenarios, however, reflects EPA’s recognition that certain subpopulations of workers exist that may be highly exposed because:

• They are not covered by OSHA standards because their employers are out of compliance with OSHA standards;
   
• OSHA’s chemical-specific permissible exposure limits (PEL) (largely adopted in the 1970s) are described by OSHA as being “outdated and inadequate for ensuring protection of worker health”; or
   
• The OSHA PEL alone may be inadequate for ensuring protection of worker health, as is the case for methylene chloride, according to EPA.
   

EPA states that as it moves forward with a risk management rulemaking for methylene chloride, it 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 states that it is now moving forward on risk management to address the unreasonable risk presented by methylene chloride. EPA notes that in taking this action, it has not conducted a new scientific analysis on methylene chloride and the risk evaluation continues to characterize risks associated with individual COUs in the risk evaluation of methylene chloride to inform risk management.

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 states that it 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 COUs that drive the unreasonable risk. EPA states that it is not limited to regulating the specific activities found to drive unreasonable risk, however, and may select from among a wide range of risk management requirements. EPA states that as a general example, it 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.

Commentary

Bergeson & Campbell, P.C. (B&C^®) commends EPA with completing its final risk determination on methylene chloride, despite facing significant resource and staffing limitations. We believe, however, that EPA’s victory lap for this accomplishment will be overshadowed by future challenges to the forthcoming risk management rule. EPA stated that its revised risk determination is “supported by science and the law.” We remind readers that there are opposing yet credible arguments that suggest otherwise, specifically as to whether EPA satisfied the scientific standards under TSCA Section 26 and the legality of EPA’s new policy directions, as discussed below.

EPA stated in the Federal Register notice for the final risk determination on methylene chloride that it “views the peer reviewed hazard and exposure assessments and associated risk characterization as robust and upholding the standards of best available science and weight of the scientific evidence per TSCA sections 26(h) and (i).” This view is not, however, supported by the U.S. National Academies of Science, Engineering, and Medicine’s (NASEM) review of EPA’s “Application of Systematic Review in TSCA Risk Evaluations” (hereinafter the “2018 SR Document”). NASEM’s review concluded that “The OPPT approach to systematic review does not adequately meet the state-of-practice [and] OPPT should reevaluate its approach to systematic review methods, addressing the comments and recommendations in this report.” We remind readers that EPA used the 2018 SR Document in each of the “first 10” risk evaluations, including methylene chloride. This is an important consideration because TSCA Section 26(h) requires EPA to make decisions under TSCA Sections 4, 5, and 6 consistent with the best available science, which includes protocols and methodologies like systematic review. EPA’s use of the 2018 SR Document also casts doubt on whether EPA met the requirements for weight of scientific evidence under TSCA Section 26(i), which EPA codified to mean a “systematic review method, applied in a manner suited to the nature of the evidence or decision…”

EPA’s new policy directions include making unreasonable risk determinations for the whole chemical substance and assume that workers will not always appropriately wear PPE. We note that the “whole chemical approach” conflicts with 40 C.F.R. Section 702.47, which unambiguously states “EPA will determine whether the chemical substance presents an unreasonable risk of injury to health or the environment under each condition of uses [sic] within the scope of the risk evaluation, either in a single decision document or in multiple decision documents.” EPA arguably has a more compelling basis for using the whole chemical approach for methylene chloride, given that 52 of the 53 COUs drove the unreasonable risk determination. Compelling or not, EPA is using a hazard-based standard as part of its unreasonable risk determination by including the one COU where EPA did not identify unreasonable risk. This approach is inconsistent with the requirements for making risk-based determinations under TSCA Section 6(a).

EPA’s policy direction on PPE and assuming that it is not always appropriately worn conflicts with TSCA Section 26(k), which requires EPA to consider reasonably available information on for example, hazard and exposure, when carrying out TSCA Sections 4, 5, and 6. We acknowledge that TSCA Section 26(k) does not state when EPA must consider reasonably available information. For example, when read in isolation, EPA could consider reasonably available information on PPE use when conducting the risk evaluation or, consistent with its current policy direction, during risk management. In either case, EPA appears to be complying with the requirements of TSCA Section 26(k). EPA did, however, provide clarity to this under 40 C.F.R. Section 702.33 where it defined reasonably available information as “information that EPA possesses or can reasonably generate, obtain, and synthesize for use in risk evaluations, considering the deadlines specified in TSCA section 6(b)(4)(G) for completing such evaluation (emphasis added).” We note that this passage does not say “for use in risk management.” Additional clarity is provided in the U.S. Congressional record, which specifically states the following about COUs:

“Conditions of Use” is a term used throughout S. 697 to describe the context in which EPA will apply the safety standard in safety assessments and determinations. The term means the “intended, known, or reasonably foreseeable circumstances” under which a chemical substance is manufactured, processed, distributed in commerce, used or disposed of. The term is not intended to include “intentional misuse” of chemicals (emphasis added).

If EPA obtains reasonably available information on PPE use or recommended use (e.g., safety data sheets) and assumes non-use of PPE in the risk evaluation, its assessment is no longer evaluating potential risks of chemical substances under the COUs. Rather, it is evaluating intentional misuses of chemical substances.

B&C encourages readers to consider the above non-exhaustive list of issues as EPA moves forward with drafting its risk management rules on methylene chloride and the other “first 10” chemical substances. The above issues are common across each of EPA’s final risk evaluations and final revised risk determinations. B&C cautions readers that these issues will lead to dangerous precedence if interested parties do not voice their concerns during the notice and comment periods for the draft risk management rules.