Ethyl chloride (EtC1) was administered via the drinking water to 5 male and 5 female Fischer 344 rats at either 0 or 0.57g EtCl/100 g water (saturation) for the 7-day palatability study and to 10 male and 10 female Fischer 844 rats at 0 or 0.57g EtCV100 g water for 14 days for the repeated dose study. Parametera evaluated for the 14-day study included in-life observations, body weight, body weight gain, feed consumption, water consumption, gross pathology, selected organ weights, histopathology, selected clinical chemistry parameters and hematology. In the palatability study, there were no treatment-related effects noted during in-life observations. Water consumption for treated rats was within 15% of control water consumption, indicating that water containing EtCI at levels of practical saturation was palatable. There were no treatment-related in-life observations recorded during the conduct of the 14-day repeated dose study. Decreased total water consumption was identified in treated rats (80.7 and 76% of controls for male and female rats, respectively), most likely associated with reduced palatability of the water containing EtCI. This was associated with the decreased feed consumption, slightly decreased body weights, and decreased body weight gains in treated animals. These effects were interpreted to be secondary to the decreased water consumption. All other parameters were within 10% of control values, indicating no treatment-related adverse effects. In conclusion, a 14-day study in which EtCI was administered in the drinking water of Fischer 844 rats at the level of practical saturation failed to demonstrate adverse toxicological effects on any of the parameters measured. In particular, there were no indications of liver toxicity based on clinical chemistry, organ weights, gross pathology, and histopathologic examination. Therefore, under the conditions of this study, the no-observed-effect level (NOEL) was the maximum dose physically possible to administer via drinking water, an estimated 297 and 861 mg EtCI/kg body weight/day for male and female rats, respectively.