The inhalation toxicity of sulfolane (tetrahydrothiophene-1,1-dioxide)

Abstract

The mean survival time (MST) of rats exposed to 11,000 mg of aerosolized sulfolane/m 3 was 19.4 hr and all rats convulsed during the exposure. The sulfolane concentration expected to yield a MST of 24 hr was calculated to be 4700 mg/m 3. After less than 24 hr of exposure, leukopenia and convulsions were observed in rats (3600 mg/m 3) or squirrel monkeys (4850 mg/m 3) exposed to high concentrations of aerosolized sulfolane. Six subacute exposures were conducted: one repeated exposure to 495 mg/m 3 for 8 hr/day, 5 days/week for 27 exposure days and five 23 hr/day, continuous exposures of approximately 90-day duration to 200, 159, 20, 4.0, and 2.8 mg/m 3. Squirrel monkeys convulsed, vomited, and died during the exposures to 495 and 200 mg/m 3. Dogs convulsed, vomited, and were unusually aggressive during continuous exposure to 200 mg/m 3, but not during repeated exposures to 495 mg/m 3. Rodents did not convulse in any of these subacute exposures. Leukopenia and increased plasma transaminase activity were found in guinea pigs exposed to 200 mg/m 3, but not those exposed to 159 mg/m 3. Hemorrhagic, inflamed lungs were also observed in most animals exposed to the two highest concentrations. In this study, no overt toxic effects were noted during exposure of rats, guinea pigs, squirrel monkeys, or dogs to 20, 4.0, or 2.8 mg of sulfolane/m 3.