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Vermiculite Insulation and Asbestos |
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Vermiculite is a mineral used in many commercial
and consumer products including insulation. Vermiculite itself has
not been shown to pose health problems. However, some vermiculite
insulation can contain asbestos fibres.
Of concern is Zonolite, a product made from vermiculite
which was used in many Canadian homes. The vermiculite insulation
sold in Canada under the name of Zonolite was extracted from the
Libby Mine in Montana, USA. This mine had a natural deposit of asbestos
which resulted in the vermiculite being contaminated with asbestos.
Vermiculite produced by the Libby Mine has not
been on the market in Canada for more than 10 years. Not all vermiculite
sold in Canada before 1990 contains asbestos fibres. However, if
you believe that your home may contain vermiculite insulation, it
is reasonable to assume that it may be contaminated with asbestos.
Asbestos can cause health problems when inhaled
into the lungs. Exposure to asbestos fibres has been associated
with asbestosis, mesothelioma and lung cancer.
Asbestosis - Asbestosis is a disease of the
lungs produced by inhalation of asbestos fibres. It is a chronic
disease with slow onset that usually requires several years of exposure.
The development and progression of asbestosis varies from individual
to individual. It is often slow with little changes over five, ten
or more years. Many cases do not progress after diagnosis. It may,
however, be quicker in some individuals than in others due to different
conditions of past dust exposure. Asbestosis is characterized by
pulmonary fibrosis. Shortness of breath is the most common presenting
symptom. In most cases, the first and often the only physical sign
is crackles, also known as rales, usually detected near the end
of a full inspiration. Chest x-rays reveal small irregular opacities
commonly distributed in the middle and lower lung fields. Lung function
tests can help to quantify the level of pulmonary dysfunction.
Mesothelioma - Mesothelioma is a cancer
of the pleural and peritoneal cells (lining of the lung and abdominal
cavity). The site of this tumor might be the lung (pleural) or the
abdomen (peritoneal). Patients with pleural mesothelioma experience
chest and shoulder pain; dry cough is frequent. With the progression
of the tumor, weight loss, weakness, and fever may occur. The time
between the initial exposure to asbestos and the clinical manifestation
of the disease(latency) is difficult to define but for mesothelioma
is quite wide, rarely less than 10 years from the time of the first
exposure and it may occur even after 40 years. As a result, the
age at which a person was first exposed to asbestos is very important
for determining the risk of contracting mesothelioma. The effect
of latency is that any daily observation of asbestos-related disease
is the result of past exposures.
Lung Cancer - Asbestos is a well-known substance
that can cause lung cancer. Lung cancer takes many years to develop,
but changes in the lung can begin almost as soon as a person is
exposed to asbestos. Lung cancer usually does not cause symptoms
in the early stages. When symptoms occur the cancer is often advanced.
Symptoms of lung cancer include chronic cough, weight loss, shortness
of breath, fever, and chest pain. These symptoms are also common
with other lung disorders, therefore to confirm the diagnosis it
is necessary to carry out laboratory tests including chest x-ray.
The best way to minimize asbestos exposure from vermiculite is to avoid removing or disturbing the insulation. The following precautions will prevent releasing asbestos fibres into the air:
- Do not use the attic for storage.
- You and your children should not go to the attic.
- If you plan to renovate, hire a professional trained and certified
to handle asbestos.
- You should never attempt to remove the insulation yourself.
- Seal all cracks and holes in the ceilings to prevent insulation
to sift through.
For further information please see the following links:
Health Canada Information
Other Government of Canada Information
Other Information
April 2004
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