APFO (> 95% pure) was administered to Sprague Dawley rats from Days 6 through 15 of gestation of inhalation as a dust (whole body exposure) for 6 hr/day at 0, 0.1, 10, and 25 mg/m (sub 3), or by gavage at 100 my/kg body weight/day in corn oil. Maternal deaths occurred in the groups given the highest level of APFO by each route and overt toxicity was evident among the surviving dams of these groups and among those of the 10 mg/m (sub 3) group. The fetuses were examined for external, visceral, and skeletal alterations and for APFO-related macroscopic and microscopic alterations of the eyes. In the postpartum period, pups from additional control and experimental dams were examined externally and ophthalmoscopically, and the usual fertility and viability indices were calculated. A teratogenic response was not demonstrated. Toxic effects on the conceptus were noted only in the groups given the highest level of APFO by each route. Hence, APFO was not demonstrated to represent a unique hazard to the conceptus of the rat.