BIOPERSISTENCE OF MAN-MADE VITREOUS SILICATE FIBERS IN THE HUMAN LUNG

There is now a substantial body of experimental data on the pulmonary biopersistence of man-made Vitreous silicate fibers (MMVSF). but human data are seriously lacking. Our knowledge in this field is essentiall y limited to a few reports of measurements oi fibers retained in lung tissue samples taken at autopsy from workers manufacturing these produ cts. Three types of exposure were studied: fibrous glass, mineral wool , and refractory ceramic fibers. Overall, the available data do not pr ovide evidence for substantial long-term retention of fibers in the hu man lung after occupational exposure to MMVSF dusts. A word of caution , however; the amount of data supporting the previous statement is muc h greater for fibrous glass than for either mineral wool or refractory ceramic fibers. There is no human data on the key question of the kin etics of pulmonary clearance of inhaled MMVSF.