Reconstruction of silica exposure in the North Carolina dusty trades.

The current occupational standard for quartz exposure is largely drawn from studies of the granite workers at Barre, Vermont. Since 1935, the North Carolina Dusty Trades program has accumulated data on work-place environmental conditions, occupational history and health status for persons exposed to silica in a broad range of mineral industries, including granite dimension stone. The environmental data have been collected with Greenburg-Smith and midget impingers and the respirable mass dust sampler. A procedure is presented to combine the results of these sampling methods and estimate exposure at the various jobs at each dusty trades plant. From an individual's occupational history, the environmental exposure estimates are used to formulate personal lifetime exposure summaries. The results of this procedure in the North Carolina granite industry compared well with historical data from Vermont granite sheds.

Cotton dust sampling, II--vertical elutriation.

Cotton dust sampling by vertical elutriation has existed since 1970. Early medical correlations using this method of sampling used median values instead of mean values because of unexpected high and low values. The methodology necessary to obtain consistent results is difficult to achieve and worthy of review.