Abstract

Twenty-two gold-miners were studied in detail six-monthly for two years after first entering mining. Six men working in the dustiest part of the mine (8,000 to 45,000 particles/ml. all sizes, in rock containing 72% free and combined silica) showed a progressive increase of blood silica, a fall in erythrocytes, and a rise in eosinophils and monocytes. The changes observed were statistically significant only in those exposed to the highest concentrations of dust and occurred before abnormalities were detectable in the chest radiograph.