Inhalation toxicity of butylene oxide

Abstract

Exposure of male and female Fischer 344 rats and B6C3F1 mice to 0,400, 800 or 1600 ppm butylene oxide vapors 6 hours per day, 5 days per week, for a total of 9 days during a 2-week interval revealed a definite species differences in sensitivity to these high concentrations of the test material. All mice in the 1600 ppm group were dead prior to the 3rd day of exposure while all rats exposed to 1600 ppm survived until scheduled sacrifice with no obvious signs of distress except for a pronounced retardation of growth. Inflammatory and degenerative changes in the nasal mucosa were detected histopathologically in rats in the 1600 ppm group. Myeloid jyperplasia in the bone marrow, and elevated mean white blood cell counts for male and female rats in the 1600 ppm group may possibly have been related to the inflammatory nasal lesions or to generalized stress. A subchronic inhalation toxicity study in which Fischer 344 rats and B6C3F1 mice were exposed to 0,75, 150 or 600 ppm for 13-weeks resulted in no treatment-related mortalities. Slight growth retardation, particularly for female rats and mice, was apparent for animals in the 600 ppm group. Histopathologic examinations revealed treatment-related lesions of the nasal mucosa in both rats and mice in the 600 ppm group. There were no histopathologic observations in rats or mice in the 75 or 150 ppm groups which were considered to be related to exposure to the test material.