Asbestos Exposure - FAQ's

What is asbestos?

"Asbestos" is the name given to a group of minerals that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven. These fibers are not affected by heat or chemicals and do not conduct electricity. For these reasons, asbestos has been widely used in many industries. Four types of asbestos have been commonly used:

  • Chrysotile, or white asbestos (curly, flexible white fibers), which accounts for about 90 percent of the asbestos currently used in industry;
  • Amosite (straight, brittle fibers that are light gray to pale brown in color);
  • Crocidolite, or blue asbestos (straight blue fibers); and
  • Anthophyllite (brittle white fibers).

Chrysotile asbestos, with its curly fibers, is in the serpentine family of minerals. The other types of asbestos, which all have needle-like fibers, are known as amphiboles.

Asbestos fiber masses tend to break easily into a dust composed of tiny particles that can float in the air and stick to clothes. The fibers may be easily inhaled or swallowed and can cause serious health problems.

How is asbestos used?

Asbestos has been mined and used commercially in North America since the late 1800s, but its use increased greatly during World War II. Since then, it has been used in many industries. For example, the building and construction industry uses it for strengthening cement and plastics as well as for insulation, fireproofing, and sound absorption. The shipbuilding industry has used asbestos to insulate boilers, steampipes, hot water pipes, and nuclear reactors in ships. The automotive industry uses asbestos in vehicle brakeshoes and clutch pads. More than 5,000 products contain or have contained asbestos, some of which are listed below:

  • Asbestos cement sheet and pipe products used for water supply and sewage piping, roofing and siding, casings for electrical wires, fire protection material, chemical tanks, electrical switchboards and components, and residential and industrial building materials;
  • Friction products, such as clutch facings; brake linings for automobiles, railroad cars, and airplanes; and industrial friction materials;
  • Products containing asbestos paper, such as table pads and heat-protective mats, heat and electrical wire insulation, industrial filters for beverages, small appliance components, and underlying material for sheet flooring;
  • Asbestos textile products, such as packing components, roofing materials, heat- and fire-resistant clothing, and fireproof draperies; and
  • Other products, including ceiling and floor tile; gaskets and packings; paints, coatings, and sealants; caulking and patching tape; and plastics.

In the late 1970s, the U.S. Consumer Product Safety Commission banned the use of asbestos in wallboard patching compounds and gas fireplaces because these products released excessive amounts of asbestos fibers into the environment. In addition, asbestos was voluntarily withdrawn by manufacturers of electric hair dryers. These and other regulatory actions, coupled with widespread public concern about the hazards of asbestos, have resulted in a significant annual decline in U.S. use of asbestos: Domestic use of asbestos amounted to about 560,000 metric tons in 1979, but it had dropped to about 55,000 metric tons by 1989.

What are the health hazards of exposure to asbestos?

Exposure to asbestos may increase the risk of several serious diseases:

  • Asbestosis-a chronic lung ailment that can produce shortness of breath and permanent lung damage and increase the risk of dangerous lung infections;
  • Lung cancer;
  • Mesothelioma - a relatively rare cancer of the thin membranes that line the chest and abdomen; and
  • Other cancers, such as those of the larynx and of the gastrointestinal tract.

How does smoking affect risk?

Many studies have shown that the combination of smoking and asbestos exposure is particularly hazardous. Cigarette smokers, on the average, are 10 times as likely to develop lung cancer as are nonsmokers. For nonsmokers who work with asbestos, the risk is about five times greater than for those in the general population. By contrast, smokers who also are heavily exposed to asbestos are as much as 90 times more likely to develop lung cancer than are nonexposed individuals who do not smoke. Smoking does not appear to increase the risk of mesothelioma, however.



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