OSHA's former 8-hour TWA limit for phenyl glycidyl ether (PGE) was 10 ppm. The Agency proposed a TWA of 1 ppm for this substance, which is consistent with the ACGIH's limit for PGE. NIOSH recommends a 15-minute ceiling limit of 1 ppm for phenyl glycidyl ether, which is a colorless liquid. In the final rule, OSHA establishes an 8-hour TWA PEL of 1 ppm for phenyl glycidyl ether.
Exposure to PGE causes systemic effects and irritation. Studies by Hine, Kodama, Wellington, and colleagues (1956/Ex. 1-331) showed pulmonary inflammation and liver changes in some of the rats exposed to 100 ppm for seven hours daily for 50 days; respiratory distress and minimal eye irritation were also observed in the exposed animals. Intragastric LD(50) values of 1.40 g/kg for mice and 3.85 g/kg for rats were also reported. Animals displayed central nervous system (CNS) depression, and death was caused by respiratory paralysis; in the survivors, these CNS effects were transient. The percutaneous LD(50) reported for rabbits was 2.99 g/kg. Other studies have reported a single-dose oral LD(50) of 4.26 g/kg, although exposure for 8 hours to the near-saturated vapor was not lethal (Smyth, Carpenter, Weil, and Pozzani 1954/Ex. 1-440). Terrill and Lee (1977/Ex. 1-390) reported kidney, liver, spleen, thymus, and testicular changes in rats exposed to phenyl glycidyl ether at 29 ppm for four hours daily, five days/week for two weeks. At concentrations of 12 or 5 ppm, these authors observed no effects other than hair loss after exposures of six hours/day, five days/week for nine weeks; however, after 18 weeks, 10 percent of male and 25 percent of female rats exhibited alopecia (hair loss). These health effects were believed by the authors to reflect direct irritation of the skin rather than systemic absorption (Terrill and Lee 1977/Ex. 1-390).
Reports of workers using or handling phenyl glycidyl ether have described moderate skin irritation on prolonged or repeated contact. In addition, several cases of skin sensitization have been reported (ACGIH 1986/Ex. 1-3, p. 476).
NIOSH (1978d/Ex. 1-232) notes that the glycidyl ethers are biologically reactive compounds because of the presence of the epoxide group; these compounds have also been shown to cause cytotoxic effects and to be mutagenic in short-term bioassays. Terrill and Lee (1977/Ex. 1-390) exposed rats repeatedly to 1 ppm PGE and observed no effects, although skin damage was observed at 5 ppm. Inconclusive evidence of testicular degeneration was reported in some of the rats exposed to levels as low as 1.75 ppm (Haskell Laboratory reports, as cited in NIOSH 1978d/Ex. 1-232, p. 114). At 10 ppm, five day/week exposures for 10 weeks caused respiratory tract irritation and early signs of liver necrosis in rats (Hine, Kodama, Wellington et al. 1956/Ex. 1-331).
OSHA received only one comment on this substance. NIOSH (Ex. 8-47, Table N6B) does not concur with OSHA's establishment of a PEL of 1 ppm for PGE; NIOSH recommends that this limit be expressed as a 15-minute short-term limit. The Agency concludes that the evidence indicates that repeated, prolonged exposures to PGE have been responsible for the adverse exposure effects observed and, therefore, that an 8-hour TWA PEL is more appropriate for this substance than a ceiling limit or STEL.
In the final rule, the Agency is reducing the 8-hour TWA PEL for phenyl glycidyl ether to 1 ppm. OSHA concludes that this limit will protect workers from the significant risk of skin sensitization, skin and respiratory tract irritation, testicular damage, and liver necrosis (all of which are material impairments of health) that are potentially associated with exposure to concentrations at the former PGE limit of 10 ppm. OSHA finds that the revised limit will substantially reduce these significant risks.