In 1987, the Division of Respiratory Disease Studies (DRDS) proposed a prospective study of the relationship between individual cumulative quartz exposure and radiographic evidence of silicosis in industrial sand workers. Data for this study were to be obtained from company Occupational Health Program (OHP) records. In order to determine whether company OHP data were suitable for the proposed study, data from 4 of the largest plants in the industry were reviewed. This report summarizes the results of this effort, paying particular attention to (1) the precision of job category quartz exposure estimates, (2) the completeness of work histories, medical examination, cigarette smoking, and demographic information, (3) the prevalence of silicosis, (4) respirator usage, and (5) analytical measurement of quartz content. These findings were indicative of the data quality that would be available to the proposed study: 1)The precision of quartz exposure estimates for most jobs in 3 of the 4 plants was marginal and was high in one plant which has followed the NISA OHP guidelines for sampling frequency. 2) Work histories were incomplete in 1 plant and possibly inaccurate in another. 3) Radiographs were available for only 56% of the 949 workers who met the study inclusion criteria and for 81% of those who had been employed 6 or more years. 4) Only 317 workers had 2 radiographs taken 5-9 years apart and only 1 worker had 2 films over 10 years apart. 5) Based on Company 'B' reader reports, the preva1ance of small radiographic opacities was 27% in workers who had been employed over 20 years. Because these data were not collected as part of an appropriately designed radiographic reading trial, accuracy of the prevalence estimates could not be determined. These data indicate a sufficient number of cases for the proposed study. These results indicate that company data are not complete and of sufficient quality at this time, and improvement of the data will be necessary before proceeding with the proposed DRDS exposure-response study of silicosis.