ETHYL ACRYLATE

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: 140-88-5; Chemical Formula: CH₂ = CHCOOC₂H₅

OSHA formerly had an 8-hour TWA limit of 25 ppm for ethyl acrylate, with a skin notation. The ACGIH has a TLV-TWA of 5 ppm, a TLV-STEL of 25 ppm, and a skin notation for ethyl acrylate, which is a colorless liquid. The proposed PEL was an 8-hour TWA of 5 ppm and a 15-minute STEL of 25 ppm, with a skin notation; the final rule establishes these limits.

Ethyl acrylate produces irritation of the skin, eyes, mucous membranes, gastrointestinal tract, and respiratory system (Dreisbach 1974/Ex. 1-896). The oral LD(50) in rats fed this substance is 1020 mg/kg, and the 4-hour inhalation LC(50) for these animals ranges between 1000 ppm and 2000 ppm. In rabbits, the dermal LD(50) is 1790 mg/kg (Pozzani, Weil, and Carpenter 1949/Ex. 1-925), and the minimum oral LD(50) is 280 to 420 mg/kg (Treon, Sigmon, Wright, and Kitzmiller 1949/Ex. 1-769). Animal studies also indicate that severe chronic effects may result from exposure to this substance. Rats exposed to levels of 70, 300, or 540 ppm of ethyl acrylate for up to 30 days showed accelerated mortality and pathologic changes in the lungs, liver, and kidneys. In those animals that developed pneumonia, renal and hepatic lesions were also seen. In a parallel study, rats, rabbits and guinea pigs who were subjected to ethyl acrylate concentrations in excess of 75 ppm for 50 seven-hour inhalation periods exhibited pulmonary edema; degenerative changes in the heart, liver, and kidneys; and death (Treon, Sigmon, Wright, and Kitzmiller 1949/ Ex. 1-769). Miller et al. (1980, as cited in ACGIH 1986/Ex. 1-3, p. 240) reported that rats and mice exposed to 75 or 225 ppm, six hours per day for 30 days, developed nasal lesions and other degenerative inflammatory changes in the nasal structure. In other studies, rats and mice administered 100 or 200 mg/kg ethyl acrylate by gavage five times per week for 103 weeks developed inflammation and hyperplasia of the forestomach in addition to squamous cell carcinomas and papillomas in the same area (NTP 1983b, as cited in ACGIH 1986/Ex. 1-3, p. 240). Based on a study by Miller et al. (1980, as cited in ACGIH 1986/Ex. 1-3, p. 240), in which rats and mice exposed to 25 or 75 ppm ethyl acrylate for six hours per day, five days per week for 27 months developed lesions in the nasal cavity even at the lowest dose, the ACGIH (1986/Ex. 1-3, p. 240) concurs with the American Industrial Hygiene Association (1966/Ex. 1-1195) that a 25-ppm limit for ethyl acrylate is too high to prevent irritating effects in exposed humans.

In a study by Nemec and Bauer (1978, as cited in ACGIH 1986/Ex. 1-3, p. 240), human volunteers experienced drowsiness, headache, and nausea after prolonged inhalation exposures at 50 to 75 ppm. Opdyke (1975/Ex. 1-922) reported that the application of a 4-percent concentration of ethyl acrylate produced skin-sensitization reactions in 10 out of 24 volunteers.

NIOSH (Ex. 8-47, Table N6B; Tr. pp. 3-97 to 3-98) believes that a full Section 6(b) rulemaking is needed for this potential occupational carcinogen. A comment from Basic Acrylic Monomer Manufacturers (Ex. 184) urges OSHA not to adopt values still on the ACGIH Notice of Intended Changes. As discussed in Section IV, OSHA is not adopting these limits.

In the final rule, OSHA is establishing an 8-hour TWA of 5 ppm and a 15-minute STEL of 25 ppm for ethyl acrylate; the skin notation is being retained. The Agency concludes that these limits will protect workers from the significant risk of severe eye, nose, and skin irritation associated with exposure to this substance at the levels permitted by OSHA’s former limit. The Agency considers these adverse effects material impairments to health.