EPICHLOROHYDRIN

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: 106-89-8; Chemical Formula: C₃H₅C10

OSHA previously had a limit of 5 ppm TWA, with a skin notation, for epichlorohydrin. OSHA proposed to reduce this limit to 2 ppm TWA, also with a skin notation, based on the ACGIH (1986/Ex. 1-3) recommendation, and the final rule establishes an 8-hour TWA limit of 2 ppm and retains the skin designation. Epichlorohydrin is an unstable liquid with an odor like that of chloroform.

In animals, epichlorohydrin is irritating and systemically toxic by all routes of exposure (Shell Chemical Corporation 1958, as cited in ACGIH 1986/Ex. 1-3, p. 233). Fatalities are caused by central nervous system and respiratory tract effects resulting from exposure to high concentrations.

In mice, single 30-minute exposures to 8300 ppm of epichlorohydrin vapor caused muscular paralysis and death from respiratory failure; similar results have been reported for dermal application of the liquid at 0.5 ml/kg in rats, and repeated oral administration at 0.1 mg/kg in mice (Shell Chemical Corporation 1958, as cited in ACGIH 1986/Ex. 1-3, p. 233). At 32 ppm (seven hours/day, five days/week) for 91 days, rats failed to show normal weight gain, and at 16 ppm they showed increased kidney size (ACGIH 1986/Ex. 1-3, p. 233). Gage (1959/Ex. 1-1052) confirmed these findings and demonstrated lung, liver, and kidney injury in rats from repeated six-hour exposures at concentrations ranging from 17 to 120 ppm. No effects were observed by this author at 9 ppm. The oral LD(50) in rats is reported as 260 mg/kg, and the dermal LD(50) in rabbits is reported as 755 mg/kg (Lawrence, Malik, Turner, and Autian 1972/Ex. 1-1058). A four-hour exposure at a level of 250 ppm was fatal to rats (Carpenter, Smyth, and Pozzani 1949/Ex. 1-722).

NIOSH (Ex. 8-47, Table N6B) did not concur with OSHA’s proposed limit for epichlorohydrin, and considers this substance a potential human carcinogen and a likely candidate for a 6(b) rulemaking. There have been reports of carcinogenicity in mice resulting from both dermal application and subcutaneous injection of epichlorohydrin (Van Duuren, Goldschmidt, Katz et al. 1974/Ex. 1-969), as well as indications of reproductive effects resulting from ingestion; in addition, mutagenic effects have been observed in microbial systems and in the fruit fly (NIOSH 1976c/Ex. 1-972).

In humans exposed to concentrations above 100 ppm for brief periods, lung edema and kidney lesions have been reported (NIOSH 1976c/Ex. 1-972). Exposure at 20 ppm caused burning of eyes and nasal mucosa (Wexler 1971, as cited in NIOSH 1976c/Ex. 1-972). Another exposure to an unknown concentration caused eye and throat irritation, nausea, dyspnea, bronchitis, and an enlarged liver (Schultz 1964/Ex. 1-1064). Painful irritation of subcutaneous tissues follows skin contact in humans (ACGIH 1986/Ex. 1-3. p. 233). The New Jersey Department of Public Health (Exs. 144, 144A) urged OSHA to establish a PEL for epichlorohydrin on the basis of EPA’s IRIS data. The use of such an approach is discussed in Section VI.A of the preamble.

OSHA is establishing an 8-hour TWA limit of 2 ppm, with a skin notation, for epichlorohydrin. The Agency concludes that this limit will protect workers from the significant risk of dermal, respiratory, liver, and kidney effects that are potentially associated with exposure to epichlorohydrin at elevated concentrations. OSHA has determined that the respiratory, liver, kidney, and dermal effects associated with exposure to epichlorohydrin represent material impairments of health. The skin notation is retained because of this substance’s capacity to penetrate the skin and cause toxicity; according to Lawrence, Malik, Turner, and Autian 1972/ Ex. 1-1058, the dermal LD(50) of epichlorohydrin in rabbits is 755 mg/kg.