A 28-day repeated dose inhalation study was conducted in Sprague Dawley rats. Nominal air concentrations were 0, 2 mg/1, 5 mg/1 and 8 mg/1. All dose groups showed decreased weight gains compared to controL Mortality was seen in the high dose group: 8 of 10 males and 3 of 10females died or were sacrificed before the end of the studies. High dose animals surviving to the end of the study were considered manal Target organ effects identified by histopathology in the high dose group included of facts on the nasal passages, cystitis and dilated bladder, and vacuotation of grey and white matter of the nervous system. Occasional lesions included increased or decreased ben..sopoietic activity of the bone marrow, hypo- or lack of spermatogenesis, pyometra, and vaginitis.