EPA Finalizes Exposure Limit for Carbon Tetrachloride, Mandates Worker Protections
A final rule from EPA requires employers to adopt worker protections for the solvent carbon tetrachloride, or CTC. The rule puts in place an existing chemical exposure limit (ECEL) for CTC of 0.03 ppm, an action level of 0.02 ppm, and other risk management measures.
CTC has been banned in consumer products since 1970, and many uses were phased out in the 1990s as required by the Montreal Protocol on Substances that Deplete the Ozone Layer. But CTC is still used in the production of refrigerants, aerosol propellants, and foam-blowing agents.
While EPA is allowing CTC to continue to be used in vinyl chloride manufacturing, re-packaging as a laboratory chemical, as a processing aid in the manufacture of agricultural products, and other uses, employers will be required to follow a workplace chemical protection plan described in the regulation. Elements of the plan include monitoring to ensure no one is exposed above the ECEL of 0.03 ppm as an 8-hour, time-weighted average—a significant reduction compared to OSHA’s permissible exposure limit of 10 ppm, the ACGIH Threshold Limit Value of 5 ppm, and the NIOSH recommended exposure limit of 2 ppm (all 8-hour TWAs). Companies have 36 months to fully implement the workplace protection program. EPA had originally proposed a 12-month implementation period.
The EPA rule also prohibits discontinued uses of CTC, such as its use as a fuel additive and in metal recovery.
High exposure to CTC can damage the liver, kidneys, and central nervous system, according to the Agency for Toxic Substances and Disease Registry. The International Agency for Research on Cancer classifies CTC as “possibly carcinogenic to humans” while the United States National Toxicology Program classifies it as “reasonably anticipated to be a human carcinogen” (PDF).
The final rule goes into effect Jan. 17, 2025. For more information, read the rule in the Federal Register, EPA’s news release, and the agency’s webpage on risk management for CTC.