What is Silica?

Silicon dioxide, also known as quartz or silica, is one of the most abundant chemical compounds on earth. It is the major constituent of sand and thus has many uses in construction and manufacturing. Removing impurities from sand such as iron creates glass and semiconductors used in computers and technology, hence the name Silicon Valley.

Silica, in terms of a health hazard, refers to crystalline silica, which includes five minerals with differing surface properties and biological reactivities. Quartz represents the most common form of crystalline silica that workers are exposed to. Engineered stone contains 93% silica or greater, quartzite has 95% silica, sandstone has approximately 60%, and granite ranges from 10%-45%. The other type of silica that poses a health hazard is Cristobalite, which is found in refractory products, diatomaceous earth, and devitrified silicate glasses such as ceramic fibres.

How does it affect the body?

Crystalline silica is one of the three major classes of inorganic dust that can cause interstitial lung disease. The other two classes belong to asbestos and coal mine dust. The primary adverse consequence of silica exposure, like that of asbestos, is the induction of lung fibrosis (silicosis). Silicosis develops when fine crystalline silica particles are inhaled into the alveolar sacs in the lungs. This damages the tissue and results in the formation of scar tissue. Prolonged exposure can damage the lungs enough to cause extensive scarring, substantially reducing lung function.

Chronic exposure to silicates has also been associated with immune alterations, an increase in scleroderma, and is associated with an increased elevated risk of lung cancer in humans. The majority of silicosis cases are a result of occupational activities, although there are some reported cases of simple silicosis in people who live in arid places with high silica content soil and dust storms.