Progressive silicosis in granite workers.

110-120. The first case of silicosis was discovered in a granite quarry and crushing plant in Lower Austria in 1958 after 30 years of freedom. A routine ϰ-ray survey then revealed no further cases but three more cases were discovered in the next two years. Detailed investigation revealed that these and further cases came from the area where the granite was crushed and loaded. In 10 years 18 cases were found out of a labour force of 170 falling to 120. Average exposure was 15 years and the disease tended to progress. Fifteen of the 18 cases came from the crushing plant where only 20 men were at risk, indicating a very high incidence within 15 years of first exposure. The risk is attributed to increased size and working capacity of the machines without improved dust suppression. This had led to dust levels over 10 times the accepted maximum in places. As well as more effective dust suppression, a reduction in staff, the wearing of masks and effective medical supervision of those particularly at risk are recommended.