Inhalation exposure of rats to vapors of 1-nitropropane at 100 ppm

Male and female Long-Evans rats were exposed by inhalation to vapors of 1-nitropropane at 100 ppm. The animals were exposed 7 hr per day, 5 days per week for periods up to $\text{21}\text{1}\text{2}$ months. Groups of rats were killed after 1, 3, 12, and 18 months of exposure and additional groups of exposed rats were removed from the exposure chamber after 3 and 12 months and held under nonexposure conditions for the remainder of the study. All animals remaining alive were killed $\text{21}\text{1}\text{2}$ months after the start of the study. The results of gross necropsies of the animals did not disclose any effects of exposure to 1-nitropropane on any of the organs or tissues. There were no histopathologic effects on the liver and, in particular, no induction of hepatocarcinomas. No effects were observed on final body weights or the weights of liver, kidney, or brain. There were no effects on serum chemistry or hematology.