Monochlorodiisobutylene vapor: acute and 9-day inhalation studies in Fischer-344 rats and B6C3F1 mice

Acute and 9-day repeated exposures to monochlorodiisobutylene (CDIB) were conducted in male and female Fischer-344 rats and B6C3F1 mice. The 4-hr LC50 values for these animals ranged between 1400 and 2100 ppm. Animals in the 9-day study were exposed at a mean concentration of 478, 97, or 25 ppm of CDIB for 6 hr per day. Treatment-related effects differed between species in this study. Body weight change was decreased in rats. Morphologic changes in the kidneys with accompanying polyuria and hematuria/hemoglobinuria were observed in male rats. The only effect observed at 25 ppm was a low incidence of hematuria/hemoglobinuria in male rats. Mice appeared unaffected by exposure to CDIB at levels as high as 478 ppm.