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Calcium Silicate

Asbestos in Calcium Silicate and Other Materials

Calcium silicate is a compound made by mixing the elements calcium and silicon. The most commonly used industrial form of this compound is also known by a proprietary brand name, Cal-Sil ®. This substance is used in a wide range of applications, including road construction, passive fire protection and in over-the-counter medications as an antacid. It is also used in commercial table salt as an anti-caking agent, since it can absorb up to 250% of its own weight in water. A form of calcium silicate, known as betite, is often found in cement. Calcium silicate is also used in plastics and as an emulsifier in paint.

Calcium silicate is used today in fireproof insulation as a "safer" alternative to asbestos. According to the website of the Occupational Safety and Health Administration and other sources, there are no proven serious health effects that result from industrial exposure to this material; laboratory rats exposed to as much as ten times the normal amount have shown no ill effects. OSHA does however recommend taking precautionary steps such as washing thoroughly after handling calcium silicate and avoiding eating, drinking, smoking or taking medication in an area where the substance is present.

In the past, calcium silicate-based pipe lagging contained asbestos fibers for added durability and flame resistance.

Calcium Silicate Products Containing Asbestos

The following partial list of calcium silicate products were known to contain asbestos:

Product Name Start Year End Year
Celotex Carey Calcium Silicate Block
Celotex Carey Calcium Silicate Pipecovering

Hazards Associated with Products

In general there is no particular asbestos risk associated with the use of today’s calcium silicate; today calcium silicate is used as a substitute for asbestos. Before 1980, however, some calcium silicate pipe lagging contained asbestos fibers, and workers applying that lagging or removing it from older buildings could come into contact with the asbestos fibers. When removing lagging from the pipes in older buildings, a sample of the lagging should be taken to ascertain whether it contains asbestos via laboratory analysis; if it does, then skilled and trained asbestos abatement professionals should be brought in to remove the dangerous material.



H.F.W. Taylor. Cement Industry (New York: Academic Press, 1990).

N/A. "Occupational Health And Safety Guideline for Calcium Silicate." U.S. Department of Labor OSHA Website
( Retrieved 9 January 2011.

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