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About Asbestos
Asbestos is a natural mineral fibre that was used for many years in the first
half of the 20th century in a number of building materials, such as
insulation and vinyl flooring. It has been proven to cause lung cancer
when the fibres are inhaled into the body.
There are 6 different types of
asbestos;
- Amosite
- Chrysotile
- Tremolite
- Actinolite
- Anthophyllite
- Crocidolite
All types of asbestos tend to
break into very tiny fibres. These individual fibres are so small that
many must be identified using a microscope. In fact, some individual
fibres may be up to 700 times smaller than a human hair. Because asbestos
fibres are so small, once released into the air, they may stay suspended
there for hours or even days.
Asbestos fibres are also virtually indestructible. They are resistant to
chemicals and heat, and they are very stable in the environment. They do
not evaporate into air or dissolve in water, and they are not broken down
over time. Asbestos is probably the best insulator known to man. Because
asbestos has so many useful properties, it has been used in over 3,000
different products.
Usually asbestos is mixed with other materials to actually form the
products. Floor tiles, for example, may contain only a small percentage
of asbestos. Depending on what the product is, the amount of asbestos in
asbestos containing materials (ACM) may vary from 1%-100%
Where is Asbestos found?
Asbestos may be found in many
different products and many different places. Examples of products that
might contain asbestos are:
- Sprayed on fire proofing
and insulation in buildings
- Insulation for pipes and
boilers
- Water Tanks and Boiler
flues
- Wall and ceiling
insulation
- Ceiling tiles
- Floor tiles
- Putties and cements
- Roof tiles and soffits
- Fuse Pads &
Insulation
- Siding shingles on old
residential buildings
- Textured coating on
walls and ceilings (Artex) in older buildings and homes
- Joint compound in older
buildings and homes
- Brake linings and clutch
pads
- Toilet cisterns &
sink pads
- Garage and Shed Roofs
When is
Asbestos Dangerous?
The most common way for asbestos
fibres to enter the body is through breathing. In fact, asbestos
containing material is not generally considered to be harmful unless it
is releasing dust or fibres into the air where they can be inhaled or
ingested. Many of the fibres will become trapped in the mucous membranes
of the nose and throat where they can then be removed, but some may pass
deep into the lungs, or, if swallowed, into the digestive tract. Once
they are trapped in the body, the fibres can cause health problems.
Asbestos is most hazardous when it is friable. The term
"friable" means that the asbestos is easily crumbled by hand,
releasing fibres into the air. Sprayed on asbestos insulation is highly
friable. Asbestos floor tile is not.
Asbestos-containing ceiling tiles, floor tiles, fire doors, artex, garage
roofs, etc. will not release asbestos fibres unless they are disturbed or
damaged in some way. If an asbestos ceiling tile is drilled or broken,
for example, it may release fibres into the air. If it is left alone and
not disturbed, it will not.
Health Effects
Because it is so hard to destroy
asbestos fibres, the body cannot break them down or remove them once they
are lodged in lung or body tissues. They remain in place where they can
cause disease.
There are three primary diseases associated with asbestos exposure:
Asbestosis
Asbestosis is a serious,
chronic, non-cancerous respiratory disease. Inhaled asbestos fibres
aggravate lung tissues, which causes them to scar. Symptoms of asbestosis
include shortness of breath and a dry crackling sound in the lungs while
inhaling. In its advanced stages, the disease may cause cardiac failure.
There is no effective treatment for asbestosis; the disease is usually
disabling or fatal. The risk of asbestosis is minimal for those who do
not work with asbestos; the disease is rarely caused by neighborhood or
family exposure. Those who renovate or demolish buildings that contain
asbestos may be at significant risk, depending on the nature of the
exposure and precautions taken.
Lung Cancer
Lung cancer causes the largest
number of deaths related to asbestos exposure. The incidence of lung
cancer in people who are directly involved in the mining, milling,
manufacturing and use of asbestos and its products is much higher than in
the general population. The most common symptoms of lung cancer are
coughing and a change in breathing. Other symptoms include shortness of
breath, persistent chest pains, hoarseness, and anemia.
People who have been exposed to asbestos and are also exposed to some
other carcinogen -- such as cigarette smoke -- have a significantly
greater risk of developing lung cancer than people who have only been
exposed to asbestos. One study found that asbestos workers who smoke are
about 90 times more likely to develop lung cancer than people who neither
smoke nor have been exposed to asbestos.
Mesothelioma
Mesothelioma is a rare form of
cancer which most often occurs in the thin membrane lining of the lungs,
chest, abdomen, and (rarely) heart. About 200 cases are diagnosed each
year. Virtually all cases of mesothelioma are linked with asbestos
exposure. Approximately 2 percent of all miners and textile workers who
work with asbestos, and 10 percent of all workers who were involved in
the manufacture of asbestos-containing gas masks, contract mesothelioma.
People who work in asbestos mines, asbestos mills and factories, and
shipyards that use asbestos, as well as people who manufacture and
install asbestos insulation, have an increased risk of mesothelioma. So
do people who live with asbestos workers, near asbestos mining areas,
near asbestos product factories or near shipyards where use of asbestos
has produced large quantities of airborne asbestos fibres.
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