CHLOROPENTAFLUOROETHANE

OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.

CAS: 76-15-3; Chemical Formula: ClCF₂CF₃

OSHA previously had no limit for chloropentafluoroethane (FC-115). The proposed PEL for this substance was 1000 ppm as an 8-hour TWA, and NIOSH (Ex. 8-47, Table N1) supported the proposal. The final rule establishes this limit. The ACGIH has a TLV-TWA of 1000 ppm for this colorless, odorless gas.

Chloropentafluoroethane is an asphyxiant at high concentrations. In dogs and rats, gastrointestinal absorption following intragastric intubation has been shown to be minimal (Terrill 1974/Ex. 1-1070; Clayton, Hood, Nick, and Waritz 1966/Ex. 1-952). Rats exposed to 800,000 ppm FC-115 with 20 percent oxygen for four hours showed no clinical or histopathologic effects (Clayton, Hood, Nick, and Waritz 1966/Ex. 1-952). Rats and guinea pigs showed no adverse clinical effects at inhalation levels of 600,000 ppm FC-115 in oxygen for two hours (Weigand 1971/Ex. 1-1102), and guinea pigs exposed to 200,000 ppm FC-115 in air for varying intervals up to two hours also exhibited no adverse signs (Breen and Wallis 1963, as cited in ACGIH 1986/Ex. 1-3, p. 133). Rats, mice, rabbits, and dogs have tolerated six-hour daily exposures of 100,000 ppm FC-115 for 90 days without adverse effects (Clayton, Hood, Nick, and Waritz 1966/Ex. 1-952), and laboratory animals have tolerated doses of 200,000 ppm for 3.5 hours daily, five days per week, for four weeks (Weigand 1971/Ex. 1-1102). FC-115’s potential for cardiac sensitization caused one of 13 unanesthetized dogs to develop cardiac sensitization after exposure to 150,000 ppm intravenously (Trochimowicz, Azar, Terrill, and Mullin 1974/Ex. 1-448). Several other studies indicate that unanesthetized dogs, rats, and monkeys receiving dosages of between 100,000 ppm and 200,000 ppm may show increased blood pressure, accelerated heart rate, myocardial depression, or altered pulmonary effects under certain conditions (Belej and Aviado 1975/Ex. 1-462; Friedman, Cammarato, and Aviado 1973/Ex. 1-416; Aviado and Belej 1975/Ex. 1-616). There were no reports of mutagenic, teratogenic, or carcinogenic toxicities in these studies. The Agency received no comments addressing chloropentafluoroethane, other than those submitted by NIOSH.

OSHA is establishing an 8-hour TWA permissible exposure limit of 1000 ppm for chloropentafluoroethane. The Agency concludes that this limit will protect workers from the significant risk of cardiac effects, which constitutes material impairment of health and functional capacity, at the high levels formerly permitted by the absence of an OSHA limit.