People are exposed to asbestos mainly by inhaling fibers in the air they breathe. This may occur during mining and processing asbestos, making asbestos-containing products, or installing asbestos insulation. It may also occur when older buildings are demolished or renovated, or when older asbestos-containing materials begin to break down. In any of these situations, asbestos fibers tend to create a dust composed of tiny particles that can float in the air.
In addition, asbestos fibers can be swallowed. This may happen when people consume contaminated food or liquids (such as water that flows through asbestos cement pipes). It may also occur when people cough up asbestos they have inhaled, and then swallow their saliva.
Many people are exposed to very low levels of naturally occurring asbestos in outdoor air as a result of erosion of asbestos-bearing rocks. The potential for such exposure is higher in areas where rocks have higher asbestos content. In some areas, asbestos may be detected in the water supply as well as in the air. It may be released into the water through several sources, such as erosion or natural deposits, corrosion from asbestos cement pipes, and the break down of roofing materials containing asbestos that are then transported into sewers.
However, the people with the heaviest exposure are those who worked in asbestos industries, such as shipbuilding and insulation. Many of these people recall working in thick clouds of asbestos dust, day after day.
Family members of asbestos workers can also be exposed to higher levels of asbestos because the fibers can be carried home on the workers’ clothing, and can then be inhaled by others in the household.
Exposure to asbestos is also a concern in older buildings. If building materials like insulation and ceiling and floor tiles begin to decompose over time, asbestos fibers can be found in indoor air and may pose a health threat. There is no health risk if the asbestos is bonded into intact finished products, such as walls and tiles. As long as the material is not damaged or disturbed (for example, by drilling or remodeling), the fibers are not released into the air. Maintenance workers who sweep up and dispose of the asbestos dust or handle damaged asbestos-containing materials are often exposed to higher levels than other occupants of these buildings. Removing asbestos from homes and other buildings can also cause some exposure, although modern asbestos abatement workers are trained to use appropriate protective equipment to minimize exposure.
Although use of asbestos has declined in many developed countries, its use is still a health hazard in some other parts of the world. Much of the world’s asbestos production is used in Eastern Europe, Latin America, and Asia, and its use is on the rise in many of these areas. In 2005, the World Health Organization estimated that 125 million people worldwide were exposed to asbestos at work, despite the known links to cancer and other lung diseases for more than 60 years.
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