Preventing Silicosis There is a general lack of awareness about the nature of the disease silicosis and about the sources of silica exposure in the worksite.  More than 1 million U.S. workers are exposed to crystalline silica (free silica).  Overexposure to crystalline silica can cause silicosis, a disabling lung disease. Sand, rock, and soil are the most common materials that contain silica.  The most common form of crystalline silica is known as quartz.  Inhalation of airborne dusts that contain crystalline silica can occur in a wide variety of settings:  mining, quarrying, and stone cutting; foundry operations; paint-blasting and sand-blasting; glass manufacturing and...