Asbestos in Refractory Products and Other Industrial Materials
Refractories are materials that are formulated to retain their shape and tensile strength in the presence of extremely high temperatures, typically those in excess of 1000 degrees Fahrenheit. As such, these materials are used for applications such as blast furnaces and kilns, industrial incinerators and even nuclear reactors. Refractory materials are an integral part of aluminum manufacturing as well. In the home, refractory materials may be found in fire brick and around heating systems. Some types of refractory products are designed to withstand corrosive chemicals, such as various types of acid.
Today, most refractory products are made with aluminum and silicon oxide, magnesium, zirconium, silicon carbide and graphite. Throughout the late 19th and much of the 20th centuries however, the preferred material was asbestos. Asbestos had several advantages over other available refractory materials; namely, it was inexpensive, easy to obtain and easy to work with. A refractory in its finished form resembles a brick or building block.
Asbestos refractory materials are no longer manufactured in the United States. However, such materials are still available from sources in China and India.
Hazards Associated with Refractory Products
Workers employed in the manufacturing of refractory products suffered considerable asbestos exposure. End users were in relatively little danger as long as the refractory products were intact. However, if the surrounding material is damaged, the asbestos was likely to become friable. This means that fibers are released into the local environment where they can remain suspended in the air and inhaled by those working in the area. Asbestos refractory materials remain in many old and abandoned factories and other industrial buildings. This poses a serious safety hazard to demolition workers and renovators when such buildings are razed or remodeled. Most state laws require that old buildings scheduled for demolition undergo an inspection for asbestos materials before work is begun. If asbestos containing refractory products are discovered, they must be removed by a licensed asbestos contractor and disposed of in accordance with federal and state environmental regulations.Sources
Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)
N/A. "About Refractories." The Refractories Institute (http://www.refractoriesinstitute.org/aboutrefractories.htm) Retrieved 19 January 2011.