Abstract
Five species of animals (dog, rabbit, rat, hamster, mouse) were exposed daily for periods of from one year to 26 months to a petroleum base mineral-oil mist at concentrations of 5 mg/m3 and 100 mg/m3. Histologic evaluation of tissues of the 100 mg/m3 exposed dogs and rats presented a significant pulmonary alveolar and hilar lymph node oil deposition and/or lipid granuloma formation after 12 months of exposure. In addition, the 100 mg/m3 dogs and rats showed a significant increase in basic and magnesium-activated phosphatase activities. The total evaluation of these studies suggests that the 5 mg/m3 concentration would present no toxic hazard upon prolonged exposure. It would appear, however, that protracted exposure at approximately 100 mg/m3 would in time produce harmful physiologic effects.
