Updated: Nov 17
Today, the U.S. Environmental Protection Agency (EPA) released for public comment a draft revision to the unreasonable risk determination for carbon tetrachloride pursuant to the Toxic Substances Control Act (TSCA) section 6(b). The draft revised risk determination proposes to find that carbon tetrachloride, as a whole chemical substance, presents an unreasonable risk of injury to human health under the conditions of use.
The carbon tetrachloride draft revised risk determination incorporates policy changes announced in June 2021 to ensure the public is protected from unreasonable risks from chemicals in a way that is supported by science and the law. EPA’s proposed revisions will ensure that, if finalized as proposed, the carbon tetrachloride risk determination better aligns with the objectives of protecting health and the environment under the amended TSCA.
Carbon tetrachloride is used in commercial settings as a raw material for producing other chemicals like refrigerants, chlorinated compounds, and agricultural products. EPA did not identify any intended, known, or reasonably foreseen consumer uses for this chemical.
EPA’s carbon tetrachloride risk evaluation identified adverse human health effects from inhalation and dermal exposures to carbon tetrachloride. Cancer effects include adrenal gland, brain, and liver tumors, and non-cancer effects include liver toxicity.
The draft revised risk determination for carbon tetrachloride does not reflect an assumption that workers always and appropriately wear personal protective equipment (PPE). 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. EPA will consider these comments, as well as other information on use of PPE and other ways industry protects its workers, as potential ways to address unreasonable risk during the risk management process.
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 they are not covered by OSHA standards, because their employers are out of compliance with OSHA standards, or because OSHA’s chemical-specific Permissible Exposure Limits (largely adopted in the 1970’s) are described by OSHA as being “outdated and inadequate for ensuring protection of worker health” (as is the case for carbon tetrachloride).
As EPA moves forward with a risk management rule for carbon tetrachloride, 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.
Overall, 13 of the 15 conditions of use EPA evaluated would drive the carbon tetrachloride whole chemical unreasonable risk determination due to risks identified for human health. Removing the assumption that workers always and appropriately wear PPE when making the whole chemical risk determination for carbon tetrachloride would not alter the conditions of use that drive the unreasonable risk determination for carbon tetrachloride. However, without the assumed use of PPE, inhalation exposures to workers would now also drive the unreasonable risk and dermal exposures would also drive the unreasonable risk due to non-cancer effects (specifically liver toxicity). In addition, the November 2020 Risk Evaluation contained a typographical error in the acute dermal point of departure (POD). This error was corrected in an errata memorandum dated July 2022 and posted to docket EPA-HQ-OPPT-2019-0499 at www.regulations.gov. The changes to the risk estimates for acute dermal exposures are reflected in the draft revision to the risk determination. The corrections do not alter the conditions of use that drive the unreasonable risk determination for carbon tetrachloride.
Two out of the 15 conditions of use do not drive the unreasonable risk: when carbon tetrachloride is processed as a reactant in reactive ion etching and in distribution in commerce. However, EPA is not proposing to make condition of use-specific risk determinations for those conditions of use or to issue an order under TSCA section 6(i)(1).
Following finalization of the revised risk determination for carbon tetrachloride, consistent with the statutory requirements of TSCA section 6(a), EPA will propose risk management regulatory action to the extent necessary so that carbon tetrachloride no longer presents an unreasonable risk. EPA expects to focus its risk management action on the conditions of use that drive the unreasonable risk. However, it should be noted that, under TSCA section 6(a), EPA is not limited to regulating the specific activities found to drive unreasonable risk and may select from among a suite of risk management requirements in section 6(a) related to manufacture (including import), processing, distribution in commerce, commercial use, and disposal as part of its regulatory options to address the unreasonable risk. 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.
Separately, EPA is conducting a screening approach to assess potential risks from the air and water pathways for several of the first 10 chemicals, including carbon tetrachloride. For carbon tetrachloride, the exposure pathways that were or could be regulated under another EPA administered statute were excluded from the 2020 risk evaluation. This resulted in the ambient air and ambient/drinking water pathways for carbon tetrachloride not being assessed. EPA’s screening approach will identify if there are risks that were unaccounted for in the risk evaluation for carbon tetrachloride. While this analysis is underway, EPA is not incorporating the screening-level approach into this draft revised unreasonable risk determination. If the results suggest there is additional risk, EPA will determine if the risk management approach being contemplated for carbon tetrachloride will protect against these risks or if the risk evaluation will need to be formally supplemented or revised.
Note that EPA has not conducted new scientific analysis on carbon tetrachloride as part of today’s actions. The carbon tetrachloride risk evaluation (as corrected by the errata memorandum) continues to characterize risks associated with individual conditions of use. EPA will continue to rely on the evaluation of each condition of use to support any determination of unreasonable risk for carbon tetrachloride as a whole chemical substance.
EPA will accept public comments on the draft revised risk determination for 30 days following publication in the Federal Register via docket EPA-HQ-OPPT-2016-0733 at www.regulations.gov.