Pulmonary pathology in workers exposed to nonasbestiform talc

We studied pulmonary tissue from seven men employed in the mining and milling of talc that contained minimal amounts of crystalline silica and asbestiform minerals. The lungs exhibited varying degrees of fibrosis, located either adjacent to the vessels and bronchi or diffusely. Semiquantitative estimations of talc in the lung tissue indicated that the extent of the pulmonary lesions corresponded to its concentration in the tissue. Histopathologic findings were evaluated with regard to duration of occupational exposure and radiographic changes in the chest. In three of the seven workers with exposures of 26, 27, and 27 years chest roentgenographic changes were consistent with pneumoconiosis. The lung tissues from four other patients with exposure histories of four, five, 13, and 19 years exhibited focal and diffuse fibrosis with accumulations of talc, but the chest x-ray films were negative. Crystallographic studies of digestates of lung tissue indicated that the talc contained few mineral impurities. An increase in dust load in the lungs was associated with duration of employment.