Asbestos refers to a group of six different minerals
that occur naturally in the environment. Asbestos is resistant
to heat and because of this property; it has been mined and widely
used in a variety of industries and products. One major use of
asbestos was in building materials and insulation.
can still come into contact with asbestos in building materials,
especially during remodeling, when old damaged walls, ceilings
and pipe fittings are repaired or removed. As asbestos ages, it
eventually becomes loose and “friable” (crumbly and
easily disturbed). When asbestos becomes friable, it is easily
dispersed into the air, and can then be inhaled by workers. Inhalation
of asbestos fibers is the main route of exposure, but these fibers
can also be swallowed and cause skin problems.
Asbestos fibers vary in length
and shape but are often microscopic in size and therefore can
bypass the lungs’ natural
defense mechanisms. These microscopic fibers can be deposited into
the deepest tissue of the lungs and can reside there for the remainder
of a person’s life.
Exposure to asbestos increases
the risk for the development of certain types of cancers, primarily
of the lung, but also cancer of the throat, esophagus and gastrointestinal
system. Asbestos is also known to cause a rare type of cancer – mesothelioma
-- a cancer of the lining of the lung.
Asbestos may cause two
types of conditions that are not cancer. Asbestosis refers to scarred lung
tissue caused by asbestos fibers. The scarring makes it hard for
lungs to do their job of getting oxygen into the blood. Asbestos-related
pleural disease refers to the scarring or thickening of the
lining of the lung (pleura).
Asbestosis, pleural scarring
and asbestos-related cancer are "dose-response" diseases.
This means that the more asbestos a person is exposed to, the
higher the risk for developing these diseases. In addition,
all asbestos-related diseases have long latency periods. This
simply means that it takes a long time from the initial exposure
to asbestos to the time the disease becomes evident. For
lung cancer, it could take up to 30 years from the time of exposure
until the cancer actually shows up. For mesothelioma, it may
take 40 years. Generally, asbestosis takes between 15 to 20 years
to show up on a chest x-ray.
The most common symptoms of asbestos-related
lung disease are shortness of breath and coughing. The symptoms
may be mild to severe, depending on the extent of the scarring. If asbestos exposure
has been extensive, a person may become very sick -- developing
severe breathing problems or breathing failure -- and may even
die. In addition, other medical problems, such as lung infections,
can be made worse by the presence of asbestos-related lung disease.
Prompt medical attention at the first sign of a chest infection
is therefore recommended for individuals with asbestosis. Depending
on the situation, doctors may give a flu or pneumonia vaccine as
a preventive measure. While there is no current cure or treatment
available for scarring of the lung, certain interventions (such
as stopping cigarette smoking) can and should be implemented to
help preserve breathing function.
Smoking cessation in general is a strongly recommended health
practice. However, this step is even more imperative in an asbestos-exposed
person who smokes. Research has shown that asbestos-exposed workers
who smoke may be 50 times more likely to get lung cancer than
a non-exposed worker who does not smoke.
Control of asbestos exposures should be done as a preventive measure.
By the time asbestos-related disease appears, it is too late to
reverse the damage; stopping exposure at this point only prevents
the disease from getting worse.
An examination by a physician trained to recognize
signs of asbestos-related disease can help identify some of the health
effects of asbestos. The most common test used to determine if the
lungs have been affected by asbestos exposure is a chest x-ray. A
doctor qualified to evaluate if there is evidence of asbestos exposure
on a chest x-ray is known as a B-reader. A B-reader evaluates a chest
x-ray according to a system developed in 1950 by the International
Labor Office (ILO) and the latest set of guidelines for this system
is known as the ILO-2000. This system reviews the chest x-ray film
for the presence of opacities (hazy streaks or spots), thickening
of the pleura (lining of the lung), and various other findings (such
as emphysema), as well as evaluates the technical quality of the