Chronic toxicity, oncogenicity, and mutagenicity studies with chlorotetrafluoroethane (HCFC-124)

Area of Science:

• Toxicology
• Environmental Chemistry

Background:

• Chlorotetrafluoroethane (HCFC-124) is an industrial chemical requiring safety evaluation.
• Assessing chronic toxicity, oncogenicity, and mutagenicity is crucial for understanding HCFC-124's environmental and health impact.

Purpose of the Study:

• To evaluate the chronic toxicity, oncogenicity, and mutagenicity of chlorotetrafluoroethane (HCFC-124).
• To determine the no-observed-adverse-effect level (NOAEL) for HCFC-124 in a long-term inhalation study.

Main Methods:

• Rats were exposed to HCFC-124 (0–50,000 ppm) for 6 hr/day, 5 days/week, over 2 years.
• Comprehensive monitoring included body weight, food consumption, clinical signs, ophthalmology, clinical pathology, and histopathology.
• Mutagenicity was assessed using Salmonella typhimurium strains, cultured human lymphocytes, and mouse bone marrow micronucleus tests.

Main Results:

• No adverse effects on body weight, food consumption, survival, or clinical pathology were observed in rats at any exposure level.
• Increased urine and plasma fluoride levels were noted but considered non-adverse metabolic byproducts.
• HCFC-124 demonstrated no toxicity or carcinogenicity in rats and was not mutagenic or clastogenic in in vitro and in vivo assays.

Conclusions:

• HCFC-124 is not toxic or carcinogenic in rats following chronic inhalation exposure up to 50,000 ppm.
• The no-observed-adverse-effect level for HCFC-124 in rats was determined to be 50,000 ppm.
• HCFC-124 does not pose a mutagenic risk based on the conducted assays.