Twenty-Eight-Day Repeated-Dose Inhalation Exposure of Rats to Diethylene Glycol Monoethyl Ether

This study was carried out to provide information on the effectsof inhalation of diethylene glycol monoethyl ether, a substanceused in industry which may be accidentally inhaled by man. Sprague-DawleyCD rats were exposed by inhalation to a test atmosphere containingdiethylene glycol monoethyl ether in a nose-only exposure systemfor 6 hr a day, 5 days a week for 28 days. Mean exposure levelswere 0.09, 0.27, and 1.1 mg/liter. At the two lowest exposurelevels the test substance was present entirely as vapor, butat the highest exposure level the test atmosphere was approximatelyequally divided by mass into respirable droplets (aerosol) andvapor. A comprehensive battery of toxicological evaluationsincluding food consumption, body weight, clinical signs, hematology,and biochemistry revealed no evidence of a systemic effect ofexposure. Histopathological examination showed changes indicativeof mild nonspecific irritation in the upper respiratory tractof rats exposed at the two highest exposure levels. These changesconsisted of foci of necrosis in the ventral cartilage of thelarynx of rats exposed at 0.27 or 1.1 mg/liter and an increasein eosinophilic inclusions in the olfactory epithelium of thenasal mucosa of rats exposed at 1.1 mg/liter. The no observedadverse effect level for systemic effects was 1.1 mg/liter andthe no observed adverse effect level for signs indicative ofmild nonspecific irritation of the upper respiratory tract was0.09 mg/liter.