1,1,1,2-TETRAFLUOROETHANE - REPEAT EXPOSURE INHALATION TOXICITY IN THE RAT, DEVELOPMENTAL TOXICITY IN THE RABBIT, AND GENOTOXICITY IN-VITROAND IN-VIVO

Subchronic and chronic studies were carried out in the rat and a devel opmental toxicity study in the rabbit with exposures to 1,1,1,2-tetraf luoroethane (HFC 134a) by inhalation. In the rat repeated exposure to 50,000 ppm HFC 134a for 13, 52, and 104 weeks elicited no effect on cl inical condition, growth, and survival, or on a variety of hematologic al, clinical chemistry, and urinary parameters, Treatment-related path ological changes were seen only at study termination at 2 years and we re confined to increased incidence of Leydig cell hyperplasia and aden oma in male rats exposed to 50,000 ppm. The tumors, which were also se en in control animals, were benign and not life-threatening, A battery of in vitro and in vivo tests gave no evidence of genotoxic activity, With exposure to pregnant rabbits, the only treatment-related effects were of minimal maternal toxicity at high exposure concentrations; th ere were no effects on fetal development, It is concluded that HFC 134 a is of very low toxicity and should be an acceptable alternative to C FCs. (C) 1995 Society of Toxicology.