Groups of six rats were exposed nose only to atmospheres of the test material for four hours. The exposures were conducted at concentrations of 4300, 2700 or 1400 ppm. Mortalities of 4/6, 1/6, and 0/6 were observed at concentrations of 4300, 2700, and 1400 ppm, respectively. At 4300 ppm, the mortalities occurred during the exposure and the one death at 2700 ppm occurred overnight following the exposure. By three hours into the exposures, all rats failed to respond to external sound stimulus. Clinical signs noted in some rats immediately post-exposure included, immobility, lethargy, ataxia and/or abnormal gait. These clinical signs were not observed the day after exposure or during the remainder of the 14-day observation period. The Approximate Lethal Concentration (ALC) was 2700 ppm.