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: 75-69-4; Chemical Formula: CCl3F
Fluorotrichloromethane (trichlorofluoromethane), also known as FC-11, is a member of a large family of chemicals, the chlorofluorocarbons. The former OSHA PEL was an 8-hour TWA of 1000 ppm. The proposed PEL was a ceiling of 1000 ppm and NIOSH (Ex. 8-47, Table N1) supported the proposal. The final rule establishes this limit. At ordinary temperatures, FC-11 is a noncombustible, colorless liquid or gas.
Inhalation of large doses of FC-11 has caused cardiac sensitization and death in humans. Experimental mice that inhaled aerosol containing 10 percent FC-11 exhibited cardiac arrhythmias. In the same study, dogs that inhaled aerosol containing 2.5 percent FC-11 had decreased myocardial function; monkeys that inhaled an aerosol containing 5 percent FC-11 developed tachycardia and hypotension (Drinking Water and Health, National Research Council 1977).
Exposure to 5000 ppm FC-11 has induced cardiac sensitization and arrhythmia in dogs that were intravenously injected with epinephrine (Reinhardt, Azar, Maxfield, Smith, and Mullin 1971/Ex. 1-78). Jenkins, Jones, Coon, and Siegel (1970/Ex. 1-95) found that four species of animals (monkeys, dogs, rats, and guinea pigs) suffered no ill effects after 90 days of continuous exposure to 1000 ppm of FC-11. Other than those submitted by NIOSH, OSHA received no comments on FC-11.
The cardiac sensitization exhibited by FC-11-exposed animals is an acute effect. OSHA’s former 1000-ppm TWA PEL would permit workers to be exposed to short-term concentrations of FC-11 that are sufficiently high to sensitize the heart to sympathomimetic amines; OSHA considers this effect to be a material impairment of health. Accordingly, OSHA concludes that, at the former limit, workers are at significant risk of experiencing arrhythmia. Revising this limit to a 1000-ppm ceiling limit will substantially reduce this significant risk of cardiac sensitization.