Asbestos
Asbestos is the general name for a wide variety of silicate minerals, mostly silicates of calcium, magnesium, and iron.
The common characteristics of the silicate minerals collectively known as asbestos are a fibrous structure and resistance to fire. Fabricated into corrugated or flat sheets, asbestos has been used as building material in a wide variety of structures, including many schools built before 1970. Formed into cylinders, it has been used for ducts and pipes. Certain types of asbestos with long fibers have been used as components in protective clothing for firefighters, brake and clutch linings for vehicles, electrical insulation, moldings for automobile components, and linings for chemical containers.
Most products manufactured today do not contain asbestos because of the deleterious health effects that have become apparent since the end of World War II. Today scientists know that asbestos can cause a range of respiratory diseases, especially asbestosis (scarring of the lung tissue), lung cancer, and mesothelioma (cancer of the chest and abdomen). These problems begin when asbestos fibers enter the respiratory system and become lodged in the interstitial areas—the areas between the alveoli in the lungs. As the fibers continue to accumulate in the lungs, they scar tissue which reduces the flow of air through the respiratory system.
Symptoms develop gradually and include coughing and shortness of breath, weight loss, and anorexia. Other respiratory conditions, such as pneumonia and bronchitis, become more common and more difficult to cure. Eventually the fibers may initiate other anatomical and physiological changes, such as the development of tumors and carcinomas.
Individuals most at risk for asbestos-related problems are those continually exposed to the mineral fibers, such as those who work in asbestos mining and processing as well as those who use the product in some other manufacturing line, such as in the production of brake linings. People who smoke cigarettes are particularly susceptible to risk. Some experts believe smokers exposed to asbestos are 90 times more likely to develop cancer than unexposed nonsmokers.
The Environmental Protection Agency (EPA) began to regulate the use of asbestos in the early 1970s when it was declared an air pollutant by the 1970 Clean Air Act. Over the past two decades, mammoth efforts have been made to remove asbestos-based materials from buildings where they are especially likely to pose health risks, such as in school buildings and public auditoriums. Children are especially susceptible to airborne pollutants and, because of their age, carry a greater potential to develop related diseases if exposed. The EPA issued special asbestos-related regulations in 1983 that required school districts to inspect their buildings and monitor air quality. Most school buildings constructed prior to the 1970s contain asbestos.
The removal of asbestos has been the subject of considerable controversy. Critics of removal maintain that, if not done properly, asbestos removal spreads more asbestos fibers into the air than it actually removes. Also, a satisfactory substitute for asbestos has not yet been found. In many cases, encapsulating the asbestos-containing material—with a thick coat of paint, for example—has been deemed a more acceptable preventive measure.
For Further Study
Books
Brodeur, Paul. Outrageous Misconduct: The Asbestos Industry on Trial. New York: Pantheon Books, 1985.
Marchok, Janice. Oh No! Not My Electric Blanket, Too? Latrobe, PA: The Jetmarc Group, 1991.
Ray, Dixy Lee. Trashing the Planet. New York: HarperPerennial, 1990.
Tate, Nicholas. The Sick Building Syndrome. Fair Hills, NJ: New Horizon Press, 1994.
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