Respiratory toxicity of enzyme detergent dust

Cynomolgus monkeys exposed 6 hr daily, 5 days/week for 6 months to atmospheres containing synthetic detergent dust at 1, 10, or 100 mg/m 3 together with enzyme dust at 0.001, 0.01, 0.1, or 1 mg/m 3 , or to the detergent dust alone at 100 mg/m 3 , or to the enzyme dust alone at 1 mg/m 3 . The enzyme was a mixture of two enzymes manufactured for use in commercial detergents: Novo Alcalase and Milezyme 8X. The mass median (aerodynamic equivalent) diameter of the dust particles was ⋍3 μm. No evident adverse effects were produced by any of the mixtures of 1 mg/m 3 detergent dust with as much as 0.1 mg/m 3 enzyme dust. The detergent dust alone at 100 mg/m 3 produced gross signs of respiratory distress, pulmonary histopathological effects, and pulmonary function impairment. This impairment, measured by the nitrogen washout method, was indicative of constricted small airways. Exposure to 10 or 100 mg/m 3 detergent dust together with 0.01 or 1 mg/m 3 enzyme dust produced the same effects along with diminished weight gain or weight losses. The 100 mg/m 3 level of detergent dust, alone and with enzyme, caused some mortality. At least one animal in each group exposed to enzyme dust had precipitating antibodies to the enzyme. Evidence of respiratory toxicity diminished greatly in animals that were held for 4 to 6 weeks after their last exposure to the dust, but single 6-hr reexposures of some of these animals reinstated many of their overt symptoms. The dust exposures had no apparent effects on total respiratory system flow resistance, diffusion capacity, hematology, clinical chemistry, urinalysis, intradermal or skin-prick challenge test results, or chest radiographs.