Rat lung tumors induced by exposure to selected poorly soluble nonfibrous particles

Rodent bioassays have been used to assess the carcinogenicity of several in haled, poorly soluble, nonfibrous particles that vary in toxicity and carci nogenic potency. There is substantial published information from chronic in halation bioassays of diesel exhaust, carbon black, titanium dioxide, talc, and coal dust. This review summarizes data from studies with exposures for 2 yr or more using these 5 materials. The review has four objectives: (1) to summarize the current information available from these bioassays concern ing exposure-dose-carcinogenic response in rats, (2) to summarize the patho logic and phenotypic features of the neoplastic response in rats, (3) to ex amine possible strain- and gender-related differences, and (4) to compare t he neoplastic responses of rat to those of other species exposed to there m aterials.