Edwards TCU 40/80 - Page 72

TOXICOLOGICAL INFORMATION (Continued)
to 50,000 ppm. HFC-126 does not produce genetic damage in bacterial or mammalian call cultures or
when tested in animals.
HFC-134a
Inhalation 4-hour LC50: 567,000 ppm in rats
A 5 or 10 second spray of vapor produced very slight eye irritation and a 24-hour occlusive application
produced slight skin irritation in rabbits. The compound is not a skin sensitizer in animals. No toxic effects
were seen in animals from exposures by inhalation to concentrations up
to 81,000 ppm. Lethargy and rapid respiration were observed at a vapor concentration of 305,000 ppm and
pulmonary congestion, edema, and central nervous system effects occurred at a vapor concentration of
750,000 ppm. Cardiac sensitization occurred in dogs at 75,000 ppm following an epinephrine challenge.
No effects in animals occurred from repeated inhalation-exposures to 99,000 ppm for two weeks or higher
concentrations to 50,000 ppm for three months. Repeated exposures to higher concentrations caused
transient tremors, incoondination and some organ weight changes. Long-term exposures produced increased
testes weights and increased urinary fluoride levels. No adverse effects were observed in male and female
rats fed diets containing 300 mg/kg/day of HFC-134a for 52 weeks. Animal testing indicates that this
compound does not have carcinogenic or mutagenic effects. Inhalation of 50 000 ppm for two years caused
an increase in benign testicular tumors in male rats. No effects were observed at lower concentrations. The
tumors were late-occurring and were judged not to be life-threatening. Embryotoxic activity has been
observed in some animal tests but only at high concentrations that were also maternally toxic.
HFC-143a
Inhalation 4-hour LC50: >540,000 ppm in rats
Single exposures by inhalation to 500,000 ppm caused anesthesia but no mortality at 540,000 ppm. Cardiac
sensitization occurred in dogs at 600,000 ppm following an intravenous challenge with epinephrine. Two, 4-week
inhalation have been conducted. In the first study, pathological changes in the testes were observed at all exposure
concentrations; no effects were observed in females. The testicular effect was considered related to the method
used to expose the rats to HFC-143a. In the second study using the same exposure concentrations, no effects were
noted in males at any concentration. Data from a 90-day study revealed no effects in male or female rats at
exposures up to 40,000 ppm. Long-term exposure caused significantly decreased body weights in male rats fed 300
(continued)
66 TCU 40/80 Temperature Control Unit