OSHA previously had no limit for 2-hydroxypropyl acrylate. A limit of 0.5 ppm as an 8-hour TWA, with a skin notation, was proposed, based on the ACGIH recommendation. NIOSH (Ex. 8-47, Table N1) concurred with the proposal, and this limit is established in the final rule. 2-Hydroxypropyl acrylate (HPA) is a colorless liquid at room temperature.
In experimental animals, 2-hydroxypropyl acrylate has a high acute toxicity. The Dow Chemical Company (1977c, as cited in ACGIH 1986/Ex. 1-3, p. 320) has reported an oral LD(50) for the rat of 0.25 to 0.5 g/kg, and a dermal LD(50) for the rabbit of approximately 0.25 mg/kg. In guinea pigs, direct contact with HPA caused severe eye burns and skin corrosion and sensitized some of the experimental animals. Rats exposed to a concentration of 650 ppm HPA in air for seven hours survived. Longer-term inhalation studies (30 days for two hours/day, six days/week) in rats, dogs, rabbits, and mice resulted in some irritation at 5 ppm (Dow Chemical Company 1977c, as cited in ACGIH 1986/Ex. 1-3, p. 320).
OSHA received no comment (other than NIOSH's) on its proposed 0.5-ppm TWA limit and skin notation for this substance. The Agency finds that this limit is necessary to protect workers from the risks of irritant effects, skin and eye burns, and sensitization effects associated with exposure to 2-hydroxypropyl acrylate; OSHA considers these effects material impairments of health. Therefore, OSHA is promulgating a TWA limit of 0.5 ppm, which is below the effect level for irritation found in experimental animals. OSHA is also adding a skin notation to the limit because 2-hydroxypropyl acetate readily penetrates the skin to cause systemic effects; the dermal LD(50) in rabbits has been reported to be 0.25 mg/kg (ACGIH 1986/Ex. 1-3).