OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.
CAS: 25013-15-4; Chemical Formula: CH3C6H4CH=CH2
OSHA is retaining its limit of 100 ppm (8-hour TWA) for vinyl toluene. NIOSH (Ex. 8-47, Table N1) concurs with the retention of this limit. The ACGIH recommends a TWA of 50 ppm with a 100-ppm short-term exposure limit. Vinyl toluene is a colorless liquid with a strong, disagreeable odor.
Wolf, Rowe, McCollister et al. (1956/Ex. 1-404) noted fatty degeneration of the liver and an increase in kidney and liver weights in rats, guinea pigs, rabbits, and monkeys subjected to approximately 100 seven- to eight-hour exposures to vinyl toluene at 1250 ppm. Some deaths occurred among the rats in this group. Animals exposed to vinyl toluene at 600 ppm appeared normal and showed no blood or urine abnormalities, no gross or microscopic tissue changes, and no changes in growth rate or organ weight (Wolf, Rowe, McCollister et al. 1956/Ex. 1-404).
Human volunteers reported eye and nose irritation at 400 ppm and objectionable odor at 300 ppm. At 50 ppm, the odor of vinyl toluene was detectable, but no irritation was experienced and the odor was not intolerable (ACGIH 1986/Ex. 1-3, p. 630). NIOSH was the only commenter on this substance.
OSHA is retaining its 8-hour TWA limit of 100 ppm for vinyl toluene; the Agency finds that this level protects workers against the significant risk of intolerable odor and irritation caused by vinyl toluene exposures in the workplace. The Agency has found no health evidence to suggest that a short term limit is necessary, and the final rule accordingly does not contain a STEL for vinyl toluene.