EPA Revises Risk Determination for Carbon Tetrachloride

A revised risk determination finalized by EPA on Dec. 27 finds that carbon tetrachloride “presents an unreasonable risk of injury to human health.” According to EPA, carbon tetrachloride is used in the production of refrigerants, chlorinated compounds, and agricultural products. Its use in consumer products was banned in 1970 by the Consumer Products Safety Commission. Adverse human health effects from using carbon tetrachloride include cancer and chronic liver toxicity from long-term inhalation and dermal exposures as well as and liver toxicity from short-term dermal exposures. The severity of the health effects associated with exposures to carbon tetrachloride prompted EPA to use its “whole chemical risk determination approach” for the chemical rather than making separate risk determinations for individual conditions of use.

The revised risk determination for carbon tetrachloride does not assume that all workers exposed to the chemical always or properly wear personal protective equipment. This “reflects EPA’s recognition that certain subpopulations of workers exist that may be highly exposed” for a number of potential reasons, the agency explains in a press release. For example, some workers could have increased exposure if they are not covered by OSHA standards or if the OSHA permissible exposure limit alone may be inadequate for ensuring that workers’ health is protected, which EPA states “is the case for carbon tetrachloride.”

OSHA’s construction and maritime industry PEL for carbon tetrachloride is 10 ppm as an 8-hour time-weighted average, its acceptable ceiling concentration is 25 ppm, and its acceptable maximum peak above the acceptable ceiling concentration for an eight-hour shift is 200 ppm for a maximum duration of five minutes in any four hours.

EPA intends to begin a risk management rulemaking for carbon tetrachloride.

“[EPA] will strive for consistency with existing OSHA requirements or best industry practices when those measures would address the identified unreasonable risk,” the agency states. “EPA will propose occupational safety measures in the risk management process that would meet [the Toxic Substances Control Act’s] statutory requirement to eliminate unreasonable risk of injury to health and the environment.”

For more information, see EPA’s press release and its risk evaluation webpage for carbon tetrachloride.