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: 4016-14-2; Chemical Formula: C6H12O2
OSHA’s former limit for isopropyl glycidyl ether (IGE) was 50 ppm as an 8-hour TWA. The ACGIH has an 8-hour TWA of 50 ppm and a 15-minute STEL of 75 ppm for IGE. NIOSH (Ex. 8-47, Table N7) recommends a limit of 50 ppm as a 15-minute ceiling. OSHA proposed an 8-hour TWA of 50 ppm and a 15-minute STEL of 75 ppm for IGE, and these limits are established in the final rule. IGE is a colorless, volatile liquid.
The 4-hour LC(50) for IGE in mice was 1500 ppm and the 8-hour LC(50) in rats was 1100 ppm (Hine, Kodama, Wellington et al. 1956/Ex. 1-331). The intragastric LD(50)s in mice and rats were 1.30 and 4.2 g/kg, respectively; in rabbits, the dermal LD(50) was 9.65 g/kg (Hine, Kodama, Wellington et al. 1956/Ex. 1-331). Fifty daily seven-hour exposures of rats to 400 ppm caused a reduced rate of weight gain, an increase in hemoglobin, a decrease in peritoneal fat, and, in some animals, emphysematous lungs and mottling of the liver (Hine, Kodama, Wellington et al. 1956/Ex. 1-331). Animals in this study also exhibited signs of ocular irritation and respiratory distress.
In humans, eye, nose, and upper respiratory irritation occurred in the technicians handling the animals in the Hine and co-workers (1956/Ex. 1-331) study; exposure levels were not specified. Dermatitis has also been reported in workers exposed to other glycidyl ethers during manufacture, and one such case involved IGE exposure (ACGIH 1986/Ex. 1-3, p. 340).
In the final rule, OSHA is retaining the 8-hour TWA of 50 ppm and adding a 15-minute STEL of 75 ppm for IGE. The Agency concludes that both the TWA and STEL are necessary to reduce the risk to workers of chronic organ effects, such as those demonstrated to occur in animals (Hine, Kodama, Wellington et al. 1956/Ex. 1-331), and the significant risk of eye, skin, and upper respiratory tract irritation associated with short-term IGE exposures at the levels permitted in the absence of a short-term limit. OSHA considers sensory irritation, dermatitis, and chronic organ effects to be material impairments of health.