Characteristics of lung dusts and their relation to dust exposure and pathological findings in the lungs.

Lung dusts were investigated, post-mortem, in twenty-five miners from mixed metal mines, tunnels, and quarries who had exposed to high concentrations of mixed dust containing about 20-25% free crystalline silica. The character of the relations found between the amount of quartz per 100 g dry tissue and the clinical, X-ray and pathological findings is similar to that established in coal miners. The difference lies in the fact that with equal amounts of quartz per 100 g dry tissue, there is less silicosis in coal miners than in our cases; the average residence time of retained dust is longer in coal miners, but its quartz per cent is lower.