OSHA formerly had no exposure limit for triphenyl amine. The proposed PEL was 5 mg/m3 as an 8-hour TWA, and the final rule adopts this limit. NIOSH (Ex. 8-47, Table N1) agrees with the selection of this PEL. The ACGIH has a 5-mg/m3 8-hour TWA limit for this substance. Triphenyl amine takes the form of colorless monoclinic prisms.
Animal studies conducted by the Eastman Kodak Company (Roudabush 1973, as cited in ACGIH 1986/Ex. 1-3, p. 612) showed an oral LD(50) in rats of 3200 to 6400 mg/kg and an oral LD(50) in mice of 1600 to 3200 mg/kg. The LD(50) by intraperitoneal administration for both rodent species exceeded 6400 mg/kg. Skin and eye sensitivity tests in both rabbits and guinea pigs were essentially negative, except that application of 5 to 20 ml/kg occlusively for four hours produced slight erythema (Roudabush 1973, as cited in ACGIH 1986/Ex. 1-3, p. 612).
OSHA is establishing a 5-mg/m3 TWA limit for triphenyl amine. The Agency concludes that this limit will protect workers against the significant risk of skin irritation, a material health impairment that is potentially associated with exposure to this substance at levels above the new PEL.