The EPA released its final risk assessment on carbon tetrachloride, published in the Federal Register on November 4, 2020, concluding that the chemical poses unreasonable risks to worker health. Next steps for the Agency will be to issue mitigation risk measures for the chemical within the next 2 years.
Carbon tetrachloride is a high production volume solvent that is now primarily used as a “feedstock” agent in the production of hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs). In chemistry terms, feedstock agents are those that are used to produce large-scale chemical reactions.
Nonfeedstock uses of carbon tetrachloride were primarily phased out with the 1995 ratification of the Montreal Protocol, an international treaty dedicated to protecting the ozone layer.
“The EPA found risks to workers associated with inhalation and dermal exposure for 13 industrial uses of carbon tetrachloride,” according to Chemical & Engineering News. “However, the agency found no unreasonable risks to workers in the semiconductor industry who use carbon tetrachloride as a reactant in reactive ion etching and to people who distribute the chemical. The EPA also found no unreasonable risks to the environment or to consumers.”
The EPA concluded that carbon tetrachloride is “likely to be carcinogenic to humans.”
In its conclusions, the Agency reports:
- “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. The agency 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 occupational non-users from 13 conditions of use of carbon tetrachloride. EPA found unreasonable risks from most commercial uses of this chemical to workers in direct contact and workers nearby but not in direct contact with carbon tetrachloride (known as occupational non-users). This includes unreasonable risks when manufacturing the chemical; processing the chemical 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 occupational non-users can come from long-term 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.”
Exposure to the chemical can cause damage to the central nervous system, kidneys, and liver and skin irritations.
Carbon tetrachloride is 1 of the first 10 chemicals the EPA is evaluating under the 2016 revised Toxic Substances Control Act (TSCA).
Other chemicals on the list include:
- Methylene chloride
- Tetrachloroethylene, also known as perchloroethylene
- A cluster of cyclic aliphatic bromide flame retardants
- Pigment Violet 29
The other assessments are planned to be finalized by the Agency this year. Learn more about the EPA’s findings on carbon tetrachloride.