Silica

The chief component of sand and a substance responsible for lung disease and cancer. Crystalline silica of respirable size is primarily quartz dust occurring in industrial and occupational settings in the form of fine, breathable particles. Respirable crystalline silica results from mining and grinding coal. In the year 2000, crystalline silica of respirable size was upgraded by the U.S. government to a "known human carcinogen." There are increased lung cancer rates in workers exposed to respirable-size (breathable) crystalline silica, primarily quartz and crystabolite, that are generated during sandblasting and similar activities in an occupational setting.