How
are people exposed to asbestos?
People
can be exposed to asbestos in different ways:
Inhaling asbestos:
Most exposures come from inhaling asbestos fibers in the
air. This can occur during the mining and processing of asbestos, when making asbestos-containing
products, or when installing asbestos insulation. It can 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 made of tiny particles that can float in the air.
Swallowing asbestos:
Asbestos fibers can also be swallowed. This can happen
when people consume contaminated food or liquids (such as water that flows
through asbestos cement pipes). It can 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-containing
rocks. The risk of this is higher in areas where rocks have higher asbestos
content. In some areas, asbestos can be detected in the water supply as well as
in the air. It can get into the water through several sources, such as rock or
soil erosion, corrosion of asbestos cement pipes, or the breakdown of roofing
materials containing asbestos that then enter the sewers after it rains.
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
high levels of asbestos because the fibers can be carried home on the workers’
clothing, and can then be inhaled by others in the household.
Asbestos exposure is also a concern in older buildings.
If building materials that contain asbestos (like older 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 people in these
buildings. Removing asbestos from homes and other buildings can also cause some
exposure, although modern asbestos abatement workers are trained to use proper
protective equipment to minimize exposure.
Although use of asbestos has declined in the United
States, people can still be exposed to asbestos in the workplace. In recent
years, the US Occupational Health and Safety Administration (OSHA) has
estimated that over a million American employees in construction and general
industries face significant asbestos exposure on the job.
The mining and use of asbestos is also still a health
hazard in some other parts of the world. Mining in the Russian Federation,
China, Kazakhstan, Brazil, Canada, and Zimbabwe accounts for almost all of the
world production of asbestos. Much of what is produced is used in the Russian
Federation (and other countries in the former Soviet Union) and Asia, and its
use is on the rise in some areas. In 2005, the World Health Organization
estimated that about 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.