EPA Will Propose to Ban Uses of CTC That Have Been Phased Out and Establish WCPP for Uses Not Prohibited

On July 17, 2023, the U.S. Environmental Protection Agency (EPA) announced that it will propose to ban uses of carbon tetrachloride (CTC) that have been phased out and establish a workplace chemical protection program (WCPP) for uses not prohibited to address the unreasonable risk to human health. EPA states in the prepublication version of the proposed rule that it determined that CTC presents an unreasonable risk of injury to health due to cancer from chronic inhalation and dermal exposures and liver toxicity from chronic inhalation, chronic dermal, and acute dermal exposures in the workplace. To address the identified unreasonable risk, EPA will propose under the Toxic Substances Control Act (TSCA) to establish workplace safety requirements for most conditions of use (COU), including the COU related to the making of low Global Warming Potential (GWP) hydrofluoroolefins (HFO), to prohibit the manufacture (including import), processing, distribution in commerce, and industrial/commercial use of CTC for COUs where information indicates use of CTC has already been phased out, and to establish recordkeeping and downstream notification requirements. EPA notes that the use of CTC in low GWP HFOs “is particularly important in the Agency’s efforts to support the American Innovation and Manufacturing Act of 2020 (AIM Act) and the Kigali Amendment to the Montreal Protocol on Substances that Deplete the Ozone Layer, which was ratified on October 26, 2022.” Comments will be due 45 days after the proposed rule is published in the Federal Register. Under the Paperwork Reduction Act (PRA), comments on the information collection provisions are best ensured of consideration if the Office of Management and Budget (OMB) receives them 30 days after the proposed rule is published in the Federal Register.

EPA states that pursuant to TSCA Section 6(b), it determined that CTC “presents an unreasonable risk of injury to health, without consideration of costs or other nonrisk factors, including an unreasonable risk to potentially exposed or susceptible subpopulations (PESS) identified as relevant to the 2020 Risk Evaluation for Carbon Tetrachloride,” under the COUs. To address the unreasonable risk, EPA will propose, under TSCA Section 6(a) to:

• Require a CTC WCPP, which would include an existing chemical exposure limit (ECEL) of 0.03 parts per million (ppm) as an eight-hour time-weighted average (TWA) to address risk from inhalation exposure in combination with direct dermal contact controls (DDCC) for the following COUs. EPA will also propose working with the regulated community and industrial hygiene experts to develop methodologies to measure CTC concentrations at or below the ECEL. The WCPP would apply to the manufacturing (including import) of CTC and other COUs that account for essentially all of the production volume of CTC:
  
  • Domestic manufacture;
     
  • Import;
     
  • Processing as a reactant in the production of hydrochlorofluorocarbons (HCFC), hydrofluorocarbons (HFC), HFOs, and perchloroethylene (PCE);
     
  • Incorporation into formulation, mixture, or reaction products in agricultural products manufacturing and other basic organic and inorganic chemical manufacturing;
     
  • Repackaging for use as a laboratory chemical;
     
  • Recycling;
     
  • Industrial and commercial use as an industrial processing aid in the manufacture of agricultural products;
     
  • Industrial and commercial use in the elimination of nitrogen trichloride in the production of chlorine and caustic soda; and
     
  • Disposal;
     
• Require use of a fume hood and dermal personal protective equipment (PPE) for the industrial and commercial use as a laboratory chemical;
   
• Prohibit these additional COUs, for which EPA understands use of CTC has already been phased out:
  
  • Incorporation into formulation, mixture, or reaction products in petrochemical-derived manufacturing;
     
  • Industrial and commercial use as an industrial processing aid in the manufacture of petrochemicals-derived products;
     
  • Industrial and commercial use in the manufacture of other basic chemicals (including manufacturing of chlorinated compounds used in solvents, adhesives, asphalt, and paints and coatings), except for use in the elimination of nitrogen trichloride in the production of chlorine and caustic soda (for which EPA is proposing a WCPP);
     
  • Industrial and commercial use in metal recovery;
     
  • Industrial and commercial use as an additive; and
     
  • Industrial and commercial use in specialty uses by the U.S. Department of Defense (DoD);
     
• Require manufacturers (including importers), processors, and distributors to provide downstream notification of the requirements; and
   
• Require recordkeeping.

EPA notes that not all TSCA COUs of CTC would be subject to regulation. Two COUs of CTC do not drive the unreasonable risk: distribution in commerce and processing as a reactant/intermediate in reactive ion etching. EPA states that it will not propose any restrictions for the processing of CTC as a reactant/intermediate in reactive ion etching. Under TSCA Section 6(a), EPA may select from among a suite of risk management requirements in TSCA Section 6(a), however, including requirements related to distribution in commerce, as part of its regulatory options to address the unreasonable risk. EPA’s proposed regulatory action and primary alternative regulatory action will include prohibitions on the distribution in commerce of CTC for certain downstream COUs.

Commentary

EPA’s proposal follows the strategy that EPA has followed for methylene chloride and PERC: ban all uses except for a select few uses (perhaps with some time-limited exemption) and for any allowed uses, impose a WCPP. As with the other two chlorinated solvents, it is not clear to us that EPA has established the facts to support a broad ban in instances that the WCPP requirements can be met. EPA has not identified unreasonable risk to the general population, so if a workplace can meet the WCPP requirements, there would be no unreasonable risk, and such use should be permitted. That the banned uses have been phased out, and therefore do not have stakeholders with a vested interest in protecting those COUs, is not a valid reason to prohibit those uses in a Section 6(a) rule. If EPA had issued a Significant New Use Rule (SNUR) for the phased-out COUs (as EPA now plans to do for future risk evaluations), an entity that found it needed to use CTC for a banned use could submit a Significant New Use Notice (SNUN) with documentation that it can meet the ECEL and DDCC and have EPA complete its review of that SNUN promptly. As proposed, this rule would simply prohibit such uses, even if the COUs meet the WCPP (including the ECEL and DDCC) requirements.

We applaud the fact that EPA did not specifically ban the use of CTC in consumer products, as such a ban would be duplicative of the existing ban by the Consumer Product Safety Commission. We are also pleased that EPA recognized the importance of the use of CTC in the manufacture of HFOs — a class of refrigerants that are vital to replace higher-global warming refrigerants and blowing agents.

EPA’s workplace protection proposals, in the form of a traditional ECEL and its new DDCC model appear to be EPA’s model for requiring specific workplace exposure standards, rather than standards that rely upon PPE. Ideally, EPA would propose a dermal ECEL in addition to an inhalation ECEL, but, as EPA has discovered with its test orders that ordered dermal hand-wipe sampling, there is no reliable way to measure dermal exposure, especially with highly volatile substances. Documenting compliance with a dermal ECEL is likely not possible for CTC. Documenting the engineering controls and other ways to prevent dermal exposure are the next best option. Whether EPA’s DDCC is workable and appropriate is a key aspect that stakeholders should review carefully.

As we have stated in our reviews of the previous proposed risk management rules, EPA continues to insist on Good Laboratory Practice (GLP) compliance for workplace monitoring, even though most industrial hygiene monitoring labs certify to Industrial Hygiene Laboratory Accreditation Program (IHLAP) administered by the American Industrial Hygiene Association (AIHA). In EPA’s standard consent order for new chemicals, a submitter may test under either GLP or IHLAP standards. EPA has not explained why IHLAP is not available for existing chemicals, nor has EPA explained why IHLAP is not sufficiently rigorous to satisfy the TSCA Section 26 standards for workplace inhalation exposure monitoring for existing chemicals.

Our greatest concern is EPA’s chronic liver cancer ECEL of 0.03 ppm. EPA did not use benchmark dose (BMD) modeling to derive the point of departure (POD). Instead, EPA used an additional 10× uncertainty factor for extrapolating from a lowest-observed-adverse-effect-concentration (LOAEC) to a no-observed-adverse-effect-concentration (NOAEC). This is an important consideration because BMD modeling is EPA’s preferred approach for dose-response assessments if the data are amenable to modeling. Further, the 10× uncertainty factor for LOAEC-to-NOAEC extrapolation is not applied when the POD is derived with BMD modeling. In the case of the CTC ECEL, the benchmark margin of exposure would be 30, rather than 300, if BMD modeling was used. It is disappointing that EPA appears to have not used the best available science and the weight of scientific evidence in setting the ECEL. This will undoubtedly be a significant issue upon which stakeholders will comment.