Abstract
The available toxicological data for 1,3-butadiene are limited and contradictory. Three month toxicity and two year carcinogenicity studies have therefore been initiated to identify any potential hazard to occupationally exposed personnel. The results of the 3 month study are reported in this paper. Five groups of Sprague-Dawley rats were exposed to 1,3-butadiene gas at atmospheric concentrations of 0, 1000, 2000, 4000 and 8000 ppm v/v respectively, 6 hours/day, 5 days/week for 13 weeks. Forty male and forty female animals were used in each group, of which 10 of each sex were killed at 2 and 6 weeks. Exposure took place in 5 chambers, in an area prepared specifically for the handling of a potentially explosive gas-air mixture at concentrations just below the lower explosive limit. No untoward effects attributable to exposure were observed, except a moderately increased salivation, particularly in female animals during the last 6–8 weeks o exposure, at higher concentrations of butadiene. No effects considered to be attributable to treatment were seen in growth rate, food consumption, hematological and blood biochemical investigations or urine analysis after 2, 6 and 13 weeks exposure. Macroscopic and histopathological examination after 2, 6 and 13 weeks exposure showed no untoward changes related to exposure to butadiene gas. Erythrocyte and brain cholinesterase, erythrocyte osmotic fragility and neutrophil phagocytosis were also unaffected by treatment.