Crystalline silica is a common mineral used in many industrial products and at construction sites. Materials like sand, concrete, stone, and mortar contain crystalline silica. Inhaling very small (respirable) crystalline silica particles causes multiple diseases, including silicosis, lung cancer, COPD, and kidney disease. The Occupational Safety and Health Administration silica rule applies to all general industry exposures to respirable crystalline silica, except in certain circumstances.