Environmental Contamination: Asbestos

Asbestos is a term for a group of naturally occurring mineral fibers that have been used by humankind since the Stone Age, when they were mixed with clay to reinforce pottery. When mining and milling techniques were refined during the industrial revolution, asbestos began to be used more extensively. From that time, asbestos was added to thousands of products until the 1970s, when dangers of the material began to be widely recognized.

Studies of laboratory animals and asbestos workers and their families have shown that exposure to airborne asbestos is extremely hazardous. Several potentially fatal diseases can be caused by this exposure: lung cancer; mesothelioma, a cancer of the membrane that lines the chest and abdominal cavities; and asbestosis, an irreversible scarring of the lungs. Symptoms of these conditions are not usually noticeable until 20 to 30 years after the initial exposure to asbestos.

Although most consumer goods produced today do not contain asbestos, 2.1 million metric tons of asbestos were used around the world in 2008. India and China are two countries with the highest use. Asbestos is banned in 50 countries. The United States, which is not among these countries, imported 1,460 metric tons of asbestos in 2008 in the forms of automobile brakes, gaskets, and cement pipe. Although asbestos is regulated by the U.S. Environmental Protection Agency (EPA) and other agencies, the gradual declining use of the material is the result of lawsuits. Because people with mesothelioma and other asbestos-related illnesses have initiated hundreds of thousands of lawsuits against companies that use asbestos, most insurance companies now refuse coverage for companies that use the material.

The potential for asbestos exposure exists in homes built before the 1980s as well as in older household products, such as appliances; walls, pipes, and ducts; floor tiles; and exterior roofing and siding materials. Asbestos was added to these products to strengthen them, to add thermal or acoustical insulation properties, or for fire protection. Typical building components and products that may contain asbestos in homes include the following:

• Steam pipes, boilers, and furnace ducts insulated with asbestos-containing materials
• Resilient floor tiles, backings on vinyl sheet flooring, and adhesives used for installing floor tiles
• Materials used as insulation around furnaces, boilers, and wood-burning stoves, such as cement sheet, millboard, paper, or plaster mixtures
• Gaskets used around doors in furnaces and wood- or coal-burning stoves
• Soundproofing or decorative sprayed-on materials on walls or ceilings
• Spackling compounds used in finishing gypsum board and textured paints
• Asbestos cement roofing or siding materials
• Artificial ashes and embers used in gas fireplaces
• Older consumer products, including fireproof gloves, stove top pads, ironing board covers, hair dryers, and toasters
• Vermiculite insulation that originated from a mine near Libby, Montana

Although asbestos cannot be positively identified through a visual inspection, building, plumbing, and heating contractors who have frequently worked with asbestos can usually make a reasonable judgment about whether asbestos is present in a material. In some situations, the best recourse is to contract for the services of professional environmental technicians who are trained in safely removing suspected asbestos-containing materials and analyzing them. Once asbestos is identified in a home, an analysis for potential safety hazards is conducted. In many cases, if asbestos is in good condition and not friable or releasing fibers into the air, it is best left alone. Disturbing asbestos that is not friable may create a hazard where none existed.

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