Exposure to silica dust among Danish stone workers was assessed from data collected in 1948-1980. After 1970, the exposure level was given in milligrams per cubic-meter and an exposure index (concentration of respirable dust divided by the threshold limit value for quartz) was calculated. The median index was 2.1 for the road and building material industry and 0.6 for the stonecutting industry. Crushing showed a median index of 2.6, compared to 1.0 for drilling, 0.9 for sieving, and 0.5 for cutting. The median index for the road and building material industry was higher for Bornholm than for other parts of Denmark. The median index of the stonecutting industry was 1.0 for Copenhagen and 0.5 for other parts of Denmark, and no data were available for Bornholm. Before 1970, the exposure level was given in particles per cubic meter, and few data were available on quartz content. Crushing showed the highest exposure before 1970.