Abstract
The fate of inhaled Fe2 59O3 in rats at short intervals of time after inhalation has been studied primarily to evaluate this material for cytokinetic studies of the lung. Following “nose only” types of exposures, complete analyses were performed on tissues and excreta. Upper and lower respiratory tract retention has been presented in two ways. The differences in clearance rates thus obtained are due to a significant early absorption or transport as reflected in carcass values. Suitability of Fe2O3 for cell studies is concluded to be adequate, but further emphasis is given to the need for characterization of this aerosol, particularly for solubility and ultrafiltrability in other test uses.