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The Basics on Silica
Silica is a mineral compound made up of one silicon atom and two oxygen atoms.
Oxygen is the
most abundant element in the earth's crust. Silicon is the second most
abundant. Due to such abundance, the formation of the compound silica in nature is
e are other
compounds that contain silicon whose names are quite similar, such as silicate and
silicone. Do not mistake these for silica. They are not the same thing.
If the individual
silica molecules are lined up in order and create a repeatable pattern then the silica is
in crystal form. We call it "crystalline" silica.
There can be more
than one repeatable pattern in silica. The various crystal patterns are given their
own name. There are quartz, cristobalite, tridymite, and other rare forms of
crystalline silica. Quartz is so common that the term quartz is often used to
refer to crystalline silica. And sand is often used to refer to quartz.
with silica can develop a disease called silicosis. This disease is 100% preventable
if appropriate steps are taken. Individuals are at risk in the workplace if: 1) the
silica can become airborne, 2) the airborne particles are a certain size, 3) the worker
breathes in the silica.
Consult the Crystalline Silica Primer [99 KB PDF, 29 pages]. US Department of
Interior (DOI)/US Bureau of Mines.
The Basics on Silicosis
Silicosis is a disease where scar tissue forms in the lungs and reduces the ability to extract
oxygen from the air.
There are three kinds of silicosis, based on amount of exposure and length of time.
- shortness of breath while exercising
- occasional bluish skin at ear lobes or lips
- loss of appetite
- occurs after 10 or more years of mild overexposure to silica
- the most common of all types
- may go undetected for years
- develops between 5 and 10 years of moderate overexposure
Silicosis renders the victim more susceptible to infection and diseases such as tuberculosis and
- develops within weeks up to five years due to breathing very large amounts of silica
Smoking increases the damage. Silicosis and smoking are deadly together.
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