A study was conducted on respirable quartz (14808607) exposures at silica flour producers for the period 1975-1986. In 1979, evaluations were performed at two silica flour facilities in Illinois for the purpose of determining worker exposure to respirable quartz. It was evident that workers at both sites had a high incidence of silicosis. Continuing with the effort, visits were made to 28 silica flour producers between 1975 and 1986. A total of 2,175 respirable quartz samples were examined and 52 percent of these exceeded the Mining Safety and Health Act (MSHA) Permissible Exposure Level (PEL). In 1984, 1985, and 1986, the percentages of samples taken which exceeded the PEL were 44, 46, and 34, respectively. The Recommended Exposure Level (REL) as established by NIOSH for pure respirable quartz limits exposure to a 10 hour time weighted average level of 0.05mg/m3. The percentage of samples of respirable quartz which exceeded this REL for the same time period were 74, 76, and 69, respectively. According to the authors, while the figures since 1979 do show the exposures to be dropping, there were still far more overexposures in this industry than in most other metal and nonmetal commodities. Without greater efforts to meet the levels required, the new cases of silicosis will continue to occur among workers in this industry.