CYCLOHEXYLAMINE

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: 108-91-8; Chemical Formula: C₆H₁₃N

OSHA had no former limit for cyclohexylamine. The ACGIH has a TLV-TWA of 10 ppm. OSHA proposed an 8-hour TWA PEL of 10 ppm; NIOSH (Ex. 8-47, Table N1) concurred with the proposed limit, and the final rule promulgates this limit. Cyclohexylamine is a liquid with a strong, fishy, amine odor.

Data concerning the acute toxicity of cyclohexylamine were reported by Eastman Kodak in 1958 (ACGIH 1986/Ex. 1-3, p. 161). In rats, the oral LD(50) of a 5-percent solution in water was between 400 and 800 mg/kg; mice fed a diet of the 1-percent aqueous solution or the undiluted amine had LD(50)s of between 200 and 400 mg/kg. Injection of the 5-percent aqueous solution in rats produced LD(50)s of between 5 and 25 mg/kg, while mice injected intraperitoneally with the 1-percent solution had LD(50)s of between 5 and 10 mg/kg. In guinea pigs, the dermal LD(50) of undiluted cyclohexylamine is reported to be between 1 and 5 ml/kg. Edema, necrosis, and eschars were reported as a consequence of these dermal exposures. In rabbits, one drop of a 50-percent solution caused complete destruction of the eye. Six-hour inhalation exposures at a vapor concentration of 12,000 ppm caused deaths in rats, but exposure to 1000 ppm caused neither toxic effects nor deaths.

Legator, Palmer, Green, and Petersen (1969/Ex. 1-496) considered cyclohexylamine to be a potential carcinogen, mutagen, or teratogen on the basis of dose-dependent chromosomal abnormalities observed in rats injected intraperitoneally with cyclohexylamine. Khera, Stolz, Gunner et al. (1971/Ex. 1-343) noted adverse effects on rat fertility, and Becker and Gibson (1970/Ex. 1-298) reported embryotoxic effects in mice intraperitoneally injected with cyclohexylamine. In contrast, Kennedy, Sanders, Weinberg et al. (1969, as cited in ACGIH 1986/Ex. 1-3, p. 161) reported no effects of exposure to cyclohexylamine on rabbit and rat fertility, reproduction, embryogenesis, or perinatal and postnatal development.

In general, there is agreement concerning the moderate to severe toxicity of cyclohexylamine and its potential for intense skin irritation and moderate skin sensitization (Sax 1968b, as cited in ACGIH 1986/Ex. 1-3, p. 161). The chemical is well known to be pharmacologically active, having sympathomimetic activity (Barger and Dale 1910/Ex. 1-1104). However, Litchfield and Swan (1971/Ex. 1-346) report that human dietary levels of 5 g/day for seven to eight days produced no pharmacologically active levels in the tissues; furthermore, no changes were detected in blood pressure, heart rate, or electrocardiograms of exposed subjects. Chronic experimental toxicity data are lacking, but Watrous and Schulz (1950/Ex. 1-940) have reported that exposure to 4 to 10 ppm of cyclohexylamine caused no symptoms of any kind in acutely exposed workmen. No comments other than those of NIOSH (Ex. 8-47) were received on this substance.

In the final rule, OSHA is establishing an 8-hour TWA PEL of 10 ppm for cyclohexylamine. The Agency concludes that limiting workplace exposures to this previously unregulated substance to the 10-ppm level will protect workers from the significant risk of severe skin and eye irritation and sensitization, all material health impairments that are associated with exposure to cyclohexylamine. OSHA has determined that this limit will substantially reduce these significant occupational risks.