The U.S. Environmental Protection Agency (EPA) published a Federal Register notice on June 24, 2020, announcing the availability of the final Toxic Substances Control Act (TSCA) risk evaluation for methylene chloride. 85 Fed. Reg. 37942. This is the first risk evaluation that EPA has completed under the Frank R. Lautenberg Chemical Safety for the 21st Century Act (Lautenberg Act) amendments to TSCA. After evaluating 53 conditions of use of methylene chloride, EPA determined that 47 conditions of use present an unreasonable risk of injury to health, while six do not present an unreasonable risk. EPA also determined that methylene chloride does not present an unreasonable risk to the environment under any conditions of use. Release of a final risk evaluation is the last step in the TSCA Section 6(b) process and will guide EPA’s efforts in applying Section 6(a) to reduce human exposure to methylene chloride “so that the chemical … no longer presents such risk.” EPA states that it “will now begin the process of developing ways to address the unreasonable risks identified and has up to one year to propose and take public comments on any risk management actions.” EPA could prohibit or limit the manufacture, processing, distribution in commerce, use, or disposal of methylene chloride. Any regulatory action will include opportunities for public comment.

Background

TSCA Section 6, as amended by the Lautenberg Act, requires EPA to conduct risk evaluations to “determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, without consideration of costs or other nonrisk factors, including an unreasonable risk to a potentially exposed or susceptible subpopulation identified as relevant to the risk evaluation by the Administrator, under the conditions of use.” The statute identifies the minimum components EPA must include in all risk evaluations. For each risk evaluation, EPA must publish a document that outlines the scope of the risk evaluation to be conducted, which includes the hazards, exposures, conditions of use, and the potentially exposed or susceptible subpopulations that EPA expects to consider. Each risk evaluation must also: (1) integrate and assess available information on hazards and exposure for the conditions of use of the chemical substance, including information on specific risks of injury to health or the environment and information on relevant potentially exposed or susceptible subpopulations; (2) describe whether aggregate or sentinel exposures were considered and the basis for that consideration; (3) take into account, where relevant, the likely duration, intensity, frequency, and number of exposures under the conditions of use; and (4) describe the weight of the scientific evidence for the identified hazards and exposure. The risk evaluation must not consider costs or other nonrisk factors. A detailed summary and analysis of the final risk evaluation rule is available in our June 26, 2017, memorandum, “EPA Issues Final TSCA Framework Rules.”

Risk Evaluation for Methylene Chloride

EPA’s “Nontechnical Summary of the Risk Evaluation for Methylene Chloride (Dichloromethane, DCM)” (Nontechnical Summary) states that methylene chloride is both produced and imported into the United States. Methylene chloride has a wide range of uses, including as a solvent, propellent, processing aid, or functional fluid in the manufacturing of other chemicals. According to EPA, a variety of consumer and commercial products use methylene chloride as a solvent, including sealants, automotive products, and paint and coating removers. The total aggregate production volume was approximately 264 million pounds between 2012 and 2015.

As part of its problem formulation for methylene chloride, EPA found that exposures to the general population may occur from conditions of use due to releases to air, water, or land. According to EPA, exposures to the general population via surface water, drinking water, ambient air, and sediment pathways fall under the jurisdiction of other environmental statutes administered by EPA, i.e., the Clean Water Act (CWA), Safe Drinking Water Act (SDWA), Clean Air Act (CAA), and Resource Conservation and Recovery Act (RCRA). EPA states that it “believes it is both reasonable and prudent to tailor TSCA risk evaluations when other EPA offices have expertise and experience to address specific environmental media, rather than attempt to evaluate and regulate potential exposures and risks from those media under TSCA.” EPA has therefore tailored the scope of the risk evaluation for methylene chloride and did not evaluate hazards or exposures to the general population in the risk evaluation, or make a risk determination for the general population.

In the final risk evaluation, EPA found unreasonable risks for cancer and non-cancer adverse effects from acute (central nervous system) and chronic (liver) inhalation and dermal exposure to methylene chloride. EPA used central nervous system effects to identify unreasonable risks in its risk evaluation because relatively small increases in exposure can lead from central nervous system effects to more severe effects, including death. EPA did not find unreasonable risks to the environment through surface water and sediment exposures from any conditions of use.

EPA found unreasonable risks to human health from 47 out of 53 conditions of use of methylene chloride:

• Consumers: EPA states that it found unreasonable risks to consumers from all consumer uses of methylene chloride. Common consumer uses include aerosol degreasers/cleaners, adhesives/sealants, paint brush cleaners, lubricants, arts and crafts glue, and automobile care products like air conditioner fluids. Risks to consumers can come from short-term inhalation and dermal (through the skin) exposure; and

• Workers and Occupational Non-Users (ONU): EPA states that it found unreasonable risks to workers from most commercial uses of methylene chloride. Additionally, EPA found unreasonable risks from most commercial uses of this chemical to workers nearby but not in direct contact with methylene chloride (known as ONUs). Common commercial uses include solvents for vapor degreasing, aerosol spray cleaners, adhesives, paint/coating remover, and automotive care products. Risks to workers and ONUs can come from both short- and long-term inhalation and dermal exposure.

The Nontechnical Summary states that EPA has determined that the following conditions of use of methylene chloride do not present an unreasonable risk of injury to health or the environment:

• Manufacturing (domestic manufacture);

• Processing: as a reactant;

• Processing: recycling;

• Distribution in commerce;

• Industrial and commercial use as laboratory chemical; and

• Disposal.

EPA notes that these determinations are considered final agency action and are being issued by order pursuant to TSCA Section 6(i)(1).

EPA determined that 47 out of 53 conditions of use of methylene chloride present an unreasonable risk of injury to health. The uses include the following categories: manufacturing (import); processing; industrial and commercial uses; and consumer uses. EPA states that it will initiate TSCA Section 6(a) risk management actions on these conditions of use as required under TSCA Section 6(c)(1). Pursuant to TSCA Section 6(i)(2), the unreasonable risk determinations for these conditions of use are not considered final agency action.

Commentary

Release of the final risk evaluation on methylene chloride, the first of what will be many final risk evaluations over the coming years and decades, is an important and momentous milestone for TSCA and for EPA. EPA is to be commended for its completion of the final risk evaluation for methylene chloride by June 19, 2020, which is the extended deadline provided for under TSCA Section 6(b)(4), i.e., three years and six months from December 19, 2016, the date risk evaluation was initiated for this and nine other substances that were selected by EPA to be the initial ten substances to undergo risk evaluation. We understand that EPA is working diligently to complete the risk evaluations for the remaining nine substances, and we look forward to their issuance.

As noted, EPA found unreasonable risks for 47 out of 53 conditions of use examined. While these conclusions will likely be disputed by some stakeholders as overstating the risks in some cases and understating them in other cases, it is clear that a substantial fraction of the ongoing conditions of use of methylene chloride presented unreasonable risks that had gone unaddressed for many years. This statement makes clear how important it was that Congress took on the issues and failings of old TSCA and upgraded TSCA Section 6 to better enable its application and use.

We note here as we did in our commentary on the draft risk evaluation, in the final risk evaluation and its consideration of general population risk, a controversial policy approach has been taken by EPA where the protections afforded by regulations under other environmental statutes sufficiently assess and effectively manage general population exposures. Based on this position, EPA did not identify a need to include those aspects in its risk evaluation and did not make a general population risk determination under TSCA. As we observed previously, whether EPA’s policy rationale for deciding to exclude these exposures in its evaluation, i.e., that it “is both reasonable and prudent to tailor TSCA risk evaluations when other EPA offices have expertise and experience to address specific environmental media, rather than attempt to evaluate and regulate potential exposures and risks from those media under TSCA,” will pass muster in the eyes of the public will be interesting to continue to observe -- but seems unlikely.

Finally, as noted above, EPA’s determination, which it issued by order, that domestic manufacture, processing as a reactant, recycling, distribution in commerce, industrial and commercial use as a laboratory chemical, and disposal do not present an unreasonable risk is considered a final agency action, and is thus subject to legal challenge. Given the array of legal challenges to date on EPA’s implementation of amended TSCA and the attention the initial risk evaluations are getting by stakeholders, it is foreseeable that EPA will be challenged on aspects of these determinations. It will be interesting to see if stakeholders who disagree with EPA’s policy approach to general population exposures can find a handhold to litigate this aspect in challenging the “no unreasonable risk” orders.