Hard metal lung disease: a clinical, histological, ultrastructural and X-ray microanalytical study.

Four employees occupied in hard metal grinding work at the same machine shop developed interstitial lung disease after 2-7 years of working. Open lung biopsies from two of them showed giant cell interstitial pneumonia with bronchiolitis. The multinucleate giant cells were shown by electron microscopy to include both pneumocytes and macrophages. The giant pneumocytes were severely damaged, the endoplasmic reticulum being swollen and the few lamellar bodies being small, and some mitoses were visible in the pneumocytes. No mitoses were found in the giant macrophages. Pulmonary dust particles were studied in situ by scanning transmission electron microscopy and energy-dispersive spectrometry. Cobalt was no longer found in most of the pulmonary hard metal particles, but it was regularly detected in grinding dust particles in air samples studied by scanning electron microscopy and energy-dispersive spectrometry.