Final Risk Evaluation for Carbon Tetrachloride Finds Unreasonable Risks to Workers and Occupational Non-Users

The U.S. Environmental Protection Agency (EPA) published the final risk evaluation for carbon tetrachloride on November 4, 2020. 85 Fed. Reg. 70147. EPA states that it reviewed 15 conditions of use, “all of which are associated with industrial and commercial work and primarily involve the manufacturing of other chemicals.” EPA found unreasonable risks to workers and occupational non-users (ONU) for 13 of the 15 conditions of use. EPA found no unreasonable risks to the environment. According to EPA, there are no consumer uses of this chemical.

EPA’s next step in the process required by the Toxic Substances Control Act (TSCA) is to develop a plan to reduce or eliminate the unreasonable risks found in the final risk evaluation. EPA states that it “is moving immediately to risk management for this chemical and will work as quickly as possible to propose and finalize actions to protect workers and occupational non-users.” EPA states that the action it could take to address these risks includes regulating how carbon tetrachloride is used or limiting or prohibiting the manufacture, processing, distribution in the marketplace, use, or disposal of carbon tetrachloride, as applicable. As with any chemical product, EPA “strongly recommends that users of products containing carbon tetrachloride continue to carefully follow all instructions on the product’s label and safety data sheet.” EPA notes that this is the fourth final risk evaluation that it has issued and that it plans to issue the six remaining final risk evaluations by the end of 2020.

Background

TSCA Section 6, as amended by the Frank R. Lautenberg Chemical Safety for the 21st Century Act (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 Carbon Tetrachloride

According to the final risk evaluation, EPA evaluated workplace exposures and water releases for the following industrial/commercial uses of carbon tetrachloride:

• Domestic manufacture;
   
• Import (including loading/unloading and repackaging);
   
• Processing as a reactant in the production of hydrochlorofluorocarbons, hydrofluorocarbon, hydrofluoroolefin, and perchloroethylene;
   
• Processing as a reactant in reactive ion etching;
   
• Processing for incorporation into formulation, mixtures, or reaction products (petrochemicals-derived manufacturing; agricultural products manufacturing; other basic organic and inorganic chemical manufacturing);
   
• Repackaging for use in laboratory chemicals;
   
• Recycling;
   
• Distribution in commerce;
   
• Industrial/commercial use as an industrial processing aid in the manufacture of petrochemicals-derived products and agricultural products;
   
• Industrial/commercial use in the manufacture of other basic chemicals (including chlorinated compounds used in solvents, adhesives, asphalt, and paints and coatings);
   
• Industrial/commercial use in metal recovery;
   
• Industrial/commercial use as an additive;
   
• Industrial/commercial use in specialty uses by the Department of Defense;
   
• Industrial/commercial use as a laboratory chemical; and
   
• Disposal.
   

EPA notes that it did not identify any “‘legacy uses’ (i.e., circumstances associated with activities that do not reflect ongoing or prospective manufacturing, processing, or distribution) or ‘associated disposal’ (i.e., future disposal from legacy uses) of carbon tetrachloride.” Therefore, EPA did not add any such uses or disposals to the scope of the risk evaluation for carbon tetrachloride following the issuance of the opinion in Safer Chemicals, Healthy Families v. EPA. EPA states that it did not evaluate “legacy disposal” (i.e., disposals that have already occurred) in the risk evaluation “because legacy disposal is not a ‘condition of use’ under Safer Chemicals.”

EPA made the following final risk evaluation findings. EPA states that in making these unreasonable risk determinations, it considered the hazards and exposure, magnitude of risk, exposed population, severity of the hazard, uncertainties, and other factors.

• There are no consumer uses of this chemical. In the final risk evaluation, EPA reviewed 15 conditions of use, all of which are associated with industrial and commercial work and primarily involve the manufacturing of other chemicals.
   
• EPA found no unreasonable risks to the environment from any conditions of use. EPA assessed the impact of carbon tetrachloride on aquatic and sediment-dwelling species through surface water and sediment exposures, and to terrestrial species. After reviewing these data, EPA found no unreasonable risk to the environment.
   
• EPA found unreasonable risks to workers and ONUs from 13 of the 15 conditions of use of carbon tetrachloride that were evaluated. EPA found unreasonable risks from most commercial uses of carbon tetrachloride to workers in direct contact and workers nearby but not in direct contact with carbon tetrachloride (known as ONUs). This includes unreasonable risks when manufacturing carbon tetrachloride; processing carbon tetrachloride as a reactant or intermediate and into formulation of other products; laboratory uses; recycling; uses in a variety of industrial and commercial applications; and disposal. Unreasonable risks to workers and ONUs include potential cancer and liver toxicity effects from long-term (chronic) inhalation or dermal (through the skin) exposures. Carbon tetrachloride does not pose an unreasonable risk for two conditions of use: when processed as a reactant in reactive ion etching and in distribution in commerce.
   

Commentary

EPA is to be commended for completing another risk evaluation. As with the other risk evaluations that EPA has completed, EPA found a mix of conditions of use that do and do not pose unreasonable risk.

The draft risk evaluation did not find any unreasonable risks for workers. This changed substantially in the final version as EPA determined that 13 of 15 conditions of use presented unreasonable risks to workers. Relative to the draft document, EPA found unreasonable risks to ONUs for several additional conditions of use. The bottom line, as noted above, is that 13 of 15 conditions of use presented unreasonable risks to both workers and ONUs and will, as required by TSCA, be regulated as needed under Section 6.

Notable in the risk evaluation is that EPA found some conditions of use that lead to unreasonable risk to workers at both the high-end and central tendency inhalation and dermal exposure scenarios, even with respiratory or dermal protection. EPA also identified some water releases from facilities that exceed EPA’s concentration of concern for aquatic toxicity.

Unlike other risk evaluations, EPA concluded that carbon tetrachloride does not have “legacy” conditions of use. There is not an installed base (like asbestos) or long-term potential sources (such as cyclic aliphatic bromide cluster (HBCD)) that could be sources of releases or exposure in the future.

The conditions of use that do not present unreasonable risks, and that therefore do not require regulation under TSCA, include processing as a reactant in reactive ion etching in semiconductor manufacturing and distribution in commerce. These determinations will be made by Section 6(i)(1) orders and are considered final agency actions subject to legal challenge.

EPA did not evaluate hazards or exposures to the general population in this risk evaluation. It, therefore, does not reach any conclusions regarding potential unreasonable risks to the general population. EPA excluded such exposures based on TSCA’s function as a “gap-filling” statute and to “efficiently use Agency resources, avoid duplicating efforts taken pursuant to other Agency programs, and meet the statutory deadlines for completing risk evaluations.” Carbon tetrachloride is regulated by EPA under the Clean Water Act, Clean Air Act, Federal Insecticide, Fungicide, and Rodenticide Act, Resource Conservation and Recovery Act, and Emergency Planning and Community Right-to-Know Act. As a result, EPA states that it “tailored the scope of the risk evaluation” using authorities in TSCA Sections 6(b) and 9(b)(1). The latter concerns TSCA’s relationship to other laws administered by EPA. EPA has used this argument in other final risk evaluations and it remains to be seen if this approach prompts legal challenge.