Silicon dioxide.
Also known as quartz or cristobalite.
Made up of fine particles much smaller than a grain of sand.
Exists in crystalline and amorphous forms.
Respirable silica refers to particles of diameter of less than 10 microm, that can be trapped in the nose , throat and lungs.
Exposure occurs industrially when silica containing materials are processed.
Silica exposure is common in industries such as construction, sandblasting, and mining.
Silicosis is associated with rheumatoid arthritis.
Silica exposure is significantly associated with antineutrophil cytoplasmic and a body-associated vasculitis.
320,000 workers in brick, concrete, pottery, sandblasters and foundry workers are at risk of exposure.