Rando RJ, et al. - Researchers undertook the current epidemiologic investigation of silicosis risk and progression in the setting of the industrial sand industry, which deals with high-purity quartz sands. For this investigation, they retrospectively estimated respirable quartz (RQ) exposures for 67 workers with silicosis and 167 matched control workers from 21 industrial sand plants, in which some started work as early as 1929. Given the high silica content of industrial sand and a long history of radiographic silicosis surveillance of industry workers, the industrial sand industry presented a unique setting for examination of silicosis risk. However, former workers constitute the great majority of silicosis cases in this industry which had exposures occurring in the distant past, that necessitates extensive retrospective exposure assessment and increases the likelihood of exposure misclassification. Nonetheless, the median cumulative exposure for cases was more than twice that of their matched controls.