Groups of male rats were exposed 6 hours daily for 2 weeks (9 exposures) via inhalation to 0, 0.1, 2.5, or 25 ppm of the test material. The exposure period was followed by a 2-week recovery period. Rats were weighed and observed for clinical signs on a daily basis. Food consumption was determined on a weekly basis. Clinical pathology and anatomic pathology evaluations were conducted on rats at the end of the exposure and recovery periods. One day following the final exposure, serum levels of thyroid stimulating hormone (TSH), triiodothyronine (Ts), and thyroxine (Ta) were measured in all rats. Rats exposed at 2.5 or 25 ppm had significantly lower mean body weights during the exposure and recovery phases and significantly lower mean body weight gains, food consumption, and food efficiency during the exposure period. No clinical signs of toxicity attributable to exposure to the test material were observed.