EPA to Propose Risk Management Measures for Carbon Tetrachloride

A forthcoming proposed rule from EPA would require covered workplaces to implement a chemical protection program that includes inhalation exposure limits and dermal protections for carbon tetrachloride. The proposed rule would set an existing chemical exposure limit (ECEL) for carbon tetrachloride of 0.03 ppm as an eight-hour time-weighted average. Businesses would need to meet new requirements for recordkeeping and notification of downstream users, and laboratories that use carbon tetrachloride would be required to provide fume hoods and personal protective equipment for dermal protection. The rule would also prohibit several uses of carbon tetrachloride that have already been phased out.

The agency’s prepublication notice (PDF) for the proposed rule indicates that the proposed ECEL is based on the point of departure for liver cancer observed in studies of mice. The ECEL is significantly lower than other exposure limits for carbon tetrachloride. Current eight-hour TWA exposure limits include OSHA’s permissible exposure limit, which is set at 10 ppm; the ACGIH threshold limit value, which is set at 5 ppm; and the Cal/OSHA PEL, which is set at 2 ppm. NIOSH has a recommended short-term exposure limit of 2 ppm. The OSHA, ACGIH, and Cal/OSHA limits all have skin notations.

Carbon tetrachloride is a solvent that is also used in the production of agricultural products and refrigerants. Among the chemicals produced with carbon tetrachloride are hydrofluoroolefins, or HFOs, a class of refrigerants that is considered to have low potential to contribute to global warming.

For more information, read the announcement of the proposed rule or browse EPA’s webpage on carbon tetrachloride risk management.