Toxicology and carcinogenesis studies of 2,3-butanedione in Wistar Han [Crl:WI(Han)] rats and B6C3F1/N mice (inhalation studies).

2,3-Butanedione is commonly used by the flavor manufacturing industry for production of artificial flavor formulations. Examples of flavored food products include popcorn, cake mixes, flour, beer, wine, margarines and soft spreads, cheese, candy, bakery products, crackers, cookies, ice cream, frozen foods, and many other food and beverage products. 2,3-Butanedione was nominated by the United Food and Commercial Workers Union for long-term inhalation studies due to outbreaks of bronchiolitis obliterans in workers exposed to its vapors. Male and female Wistar Han [Crl:WI(Han)] rats and B6C3F1/N mice were exposed to 2,3-butanedione (greater than or equal to 98.5%) by inhalation for 3 months or 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium and Escherichia coli, mouse bone marrow cells, and rat and mouse peripheral blood erythrocytes. (Abstract Abridged).