Toxicology and Carcinogenesis Studies of Xylenes (Mixed) (60% m-Xylene, 14% p-Xylene, 9% o-Xylene, and 17% Ethylbenzene) (CAS No. 1330-20-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies)

摘要

The technical grade of xylenes (mixed) is a clear, colorless, aromatic liquid used as a solvent in the paint, printing, rubber, and leather industries and in the manufacture of mirrors. The mixture is also used as a cleaning agent (especially in microscope technique), as a degreaser, and as a constituent of aviation and automobile fuels. Xylenes (mixed) was nominated and selected for toxicology and carcinogenesis studies because of its large annual production, significant worker exposure, potential consumer exposure and a lack of adequate long-term carcinogenicity studies in animals or epidemiologic studies in humans. Toxicology and carcinogenesis studies were conducted by administering 0, 250, or 500 mg/kg xylenes in corn oil by gavage to groups of 50 F344/N rats of each sex, 5 days per week for 103 weeks and to groups of 50 B6C3F sub 1 mice of each sex at doses of 0, 500, or 1,000 mg/kg on the same schedule. Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenicity of xylenes (mixed) for male or female F344/N rats or for male or female B6C3F sub 1 mice.