ACUTE AND SUBCHRONIC TOXICITY OF 1,1-DICHLORO-1-FLUOROETHANE (HCFC-141B)

The acute and subchronic toxicity of 1,1-dichloro-1-fluoroethane (HCFC -141b), a CFC alternative, was evaluated in several acute and subchron ic studies to assist in establishing proper handling guides. Data from acute toxicity studies in rats and rabbits demonstrated that HCFC-141 b has very low acute toxicity. HCFC-141b was not a skin irritant, but was a mild eye irritant, in rabbits and was not a skin sensitizer in g uinea pigs. Skin application of HCFC-141b to rabbits at 2000 mg/kg bod y weight produced no adverse effects. Oral administration at 5000 mg/k g body weight did not cause any deaths or clinical signs of toxicity i n rats. The 4-hr LC(50) for HCFC-141b was about 62,000 ppm in rats. Re peated exposures of rats for 6 hr/day, 5 days/wk for up to 90 days at concentrations of 2000, 8000 or 20,000 ppm did not result in significa nt adverse effects. Minor, but dose-dependent, reductions in body weig ht were observed in male and female rats during the 90-day study. Decr eased responsiveness was also observed in rats but only at 20,000 ppm. An increase in serum cholesterol or triglycerides was observed in mal e and female rats at 20,000 ppm, and in males at 8000 ppm. No specific organ pathology was noted in these subchronic inhalation studies. The no-observable-adverse-effect level (NOAEL) from these studies was 800 0 ppm. Results from other studies demonstrate that HCFC-141b was not n eurotoxic in rats. As with trichlorofluoroethane (CFC-11), a cardiac s ensitization response to an intravenous epinephrine challenge occurred in dogs with HCFC-141b at 5000 ppm and higher concentrations in exper imental screening studies.