Toxicity studies of o-chloropyridine administered dermally and in drinking water to F344/N rats and B6C3F1/N mice.

o-Chloropyridine is used as an intermediate in synthetic organic, pharmaceutical, and agricultural chemical (fungicides, herbicides) manufacture. It is also used as a catalyst for phase transfer and is a key intermediate in the manufacture of pyrithione-based biocides for use in cosmetics and various pharmaceutical products. o-Chloropyridine is available in purified (99%), technical (95%), or crude (80%) grades. o-Chloropyridine was nominated for testing by the NTP based on increasing production and use as a site-limited pharmaceutical and agrochemical intermediate, the potential for occupational and environmental exposures during its manufacture, its persistence in the environment (lasting longer than 6 months), evidence of mutagenicity based on results of several short-term test systems, and suspicion of carcinogenicity based on effects associated with structurally related chemicals. Male and female F344/N rats and B6C3F1/N mice received o-chloropyridine (99% pure) dermally for 2 weeks or in drinking water for 3 months. Genetic toxicology studies were conducted in Salmonella typhimurium and mouse peripheral blood erythrocytes. (Abstract Abridged).