Asbestos in Wallboard and Other Building Materials
Asbestos-containing wallboard was usually made from a material known as transite. This is basically portland cement to which asbestos fiber has been added. This resulted in a type of wallboard that was lightweight, yet strong and quite durable. Transite was also used in the manufacture of roofing materials as well as fire-resistant home siding and even water systems (according to one source, there may be as much as 400,000 miles of municipal water line across North America where transite pipe still exists.)
Transite was originally a product of the Johns-Manville Corporation. Eventually however, the word came to be applied to all asbestos-cement composite materials, regardless of manufacturer. Prior to the 1980s, transite contained up to 50% asbestos fiber. Today’s transite uses crystalline silica to replace asbestos.
Wallboard Products Containing Asbestos
The following partial list of wallboard products were known to contain asbestos:
|Product Name||Start Year||End Year|
|Kaiser Gypsum Mineral Fibreboard|
|National Gypsum Asbestone Cement Wallboard|
|National Gypsum Gold Bond Humiguard|
|National Gypsum Gold Bond Natcor|
|National Gypsum Gold Bond Wallboard|
Hazards Associated with Wallboard Products
While asbestos wallboard put those who worked in the manufacture of the product as well as construction workers at risk for asbestos disease, it is not necessarily a danger unless its condition has begun to deteriorate. Intact transite wallboard keeps the asbestos fibers from entering the atmosphere. However, when damaged by fire, water, impact, or simply worn from age and use, the asbestos in the wallboard can become friable, meaning that the individual fibers are very easily emitted into the atmosphere. Inhalation of asbestos fibers is the primary known cause of mesothelioma.Sources
Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)
N/A. "Asbestos Linked to Autoimmune Diseases." Environmental Health Perspectives, vol. 113 (2004)
Robson, Barbara. "Asbestos: 400,000 Miles of Drinking Water Pipes May Have Been Made With The Deadly Substance."
(http://www.doulton.ca/asbestos.html) Retrieved 3 January 2011.