Petroleum hydrocarbon toxicity studies: IX. Animal and human response to vapors of “80 Thinner”

Abstract

The suggested hygienic standard for human inhalation of “80 Thinner”, based upon the results of inhalation studies with rats and dogs and the sensory response of human subjects, is 0.45 mg/liter (100 ppm). The LC50 for rats that inhaled “80 Thinner” for 4 hr was 27 (24 to 30) mg/liter or 6200 (5500 to 6900) ppm. Rats tolerated 3.5 mg/liter (810 ppm) and dogs 2.1 mg/liter (480 ppm) for 4 hr without visible discomfort. Four cats that inhaled 24.0 mg/liter (5500 ppm) for 4 hr had signs suggestive of central nervous system effect, became prostrate in 41 to 65 min, but recovered and survived the 14-day observation period. After inhaling a concentration of 1.7 mg/liter (390 ppm) for 6 hr/day, 5 days per week, neither rats nor dogs were statistically significantly different from their controls in any criterion of effect after 14 weeks of inhalation. The oder threshold, as determined by a sniff test involving six human subjects, is approximately 0.004 mg/liter (0.9 ppm). Only slight, transitory eye irritation was reported by one of six human subjects immediately following a 15-min period in 0.45 mg/liter (100 ppm) and variable responses as to comfort at about 1.0 mg/liter (230 ppm). It is anticipated that 0.45 mg/liter (100 ppm) would be tolerable for continuous inhalation in the workroom atmosphere.