OSHA formerly had no limit for 1,3-dichloropropene. The Agency proposed an 8-hour TWA of 1 ppm, with a skin notation, for this straw-colored, clear liquid with a chloroform-like odor. NIOSH (Ex. 8-47, Table N6A) concurred with the proposed limit, which is established in the final rule. This compound occurs in two forms: cis- and trans-isomers.
In male and female rats, the acute oral LD(50)s for a 92-percent mixture of the cis- and trans-isomers of 1,3-dichloropropene were 713 and 470 mg/kg, respectively; postmortem examination showed liver and kidney damage and evidence of possible lung injury (Torkelson and Oyen 1977/Ex. 1-532). The dermal LD(50) in rabbits for a 92-percent undiluted mixture was 504 mg/kg, but a 10-percent solution administered by gavage at a dose of 125 or 250 mg/kg was lethal to some of the animals (Torkelson and Oyen 1977/Ex. 1-532). Contact with the liquid was irritating to the eyes and skin of rabbits (Torkelson and Oyen 1977/Ex. 1-532).
Inhalation exposures to 1,3-dichloropropene vapor concentrations above 2700 ppm produced eye and nasal irritation and severe lung, nasal, kidney, and liver damage in rats (Torkelson and Oyen 1977/Ex. 1-532). Exposure to 1000 ppm caused eye and nasal irritation, lacrimation, and, if prolonged, unconsciousness; rats exposed to 1000 ppm for two hours died, but those exposed for one hour survived (Torkelson and Oyen 1977/Ex. 1-532). Guinea pigs exposed to 400 ppm for a single seven-hour period died, while rats exposed similarly survived but had obvious lung congestion (Torkelson and Oyen 1977/Ex. 1-532). Rats, rabbits, guinea pigs, and dogs were exposed seven hours/day, five days/week for six months to 1-ppm or 3-ppm concentrations of 1,3-dichloropropene (Torkelson and Oyen 1977/Ex. 1-532). No adverse effects were observed in any of the animals exposed at 1 ppm. Of the animals exposed at 3 ppm, only male rats showed adverse effects; these animals had reversible cloudy swelling of the renal tubular epithelium (Torkelson and Oyen 1977/Ex. 1-532).
In humans, acute exposures to 1,3-dichloropropene cause skin, eye, and respiratory irritation (Torkelson and Oyen 1977/Ex. 1-532). There are no data on the effects in humans of chronic exposure to this substance. NIOSH (Ex. 8-47, Table N6A; Tr. 3-96 to 3-97) concurs with the limits being established by OSHA but notes that 1,3-dichloropropane could be classified as a potential occupational carcinogen. The new Jersey Department of Public Health urged OSHA to derive a PEL for this substance based on EPA's IRIS data. The use of such data is discussed in Section VI.A.
OSHA is establishing an 8-hour TWA limit of 1 ppm, with a skin notation, for 1,3-dichloropropene. The Agency concludes that this limit will protect workers against the significant risks of eye and mucous membrane irritation and lung, kidney, and liver damage, all of which constitute material health impairments that are associated with exposure to this substance. A skin notation is established to protect against 1,3-dichloropropene's ability to cause systemic toxicity when absorbed through the skin.