Zinc omadine (13463-41-7) was evaluated for acute inhalation toxicity in six groups of 5 male and 5 female Sprague-Dawley albino rats exposed to the test material at concentrations of 0.054, 0.14, 0.16, 0.82, 1.4 and 1.5 mg/L for 4 hours. The use of controls was not specified. The animals were observed for 14-days post-exposure. Mortality was observed at all exposure levels, with deaths occurring most frequently on day 1 after exposure. No deaths occurred past day 3 post-exposure. Clinical observations on the day of exposure at all concentration levels included prostration, gasping, labored breathing, rales, trembling and hunched posture. Clinical signs after exposure included urine stained abdomen, labored breathing, rales, lacrimation and red material around the nose/eyes/mouth. Exposure related abnormalities at necropsy were limited to the respiratory tract and were characterized by congestion. Histopathological examination was not specified. The LC50 for males and females combined was 0.14 (0.1-0.2) mg/L.