What is Asbestos?
Asbestos is a generic term describing a number of naturally occurring fibrous minerals that have been used in a wide range of products because of their insulating, acoustical, fire protective and chemical resistance properties. According to some definitions, there are as many as 30 varieties of asbestos, however only six are of commercial use. These six are listed in the asbestos definition section 1 of the regulation 278/05: antinolite, amosite, anthophylite, chrysotile, crocidilite and tremolite.
Two classes of asbestos products were widely used. The first class includes materials easily crumbled or loose in composition. These are referred to as “friable”. The second type includes materials much more durable because they are held together by a binder such as cement, vinyl, or asphalt. These products are termed “non friable”.
The release of asbestos fibres from asbestos-containing materials is primarily a result of activities that result in their disturbance. In order to prevent the exposure of individuals to harmful levels of asbestos fibres, proper precautions and safe work procedures must be implemented, when any work is conducted on or close to asbestos contaminated materials. In addition, regular inspections to readily identify damaged or deteriorating materials must be conducted so that they can be promptly addressed.
HOW HAS ASBESTOS BEEN USED?
During the 1930’s up to the late 1970’s, asbestos was used in many building materials. To date many buildings and houses constructed during that time period still contain some form of asbestos materials, such as sprayed fibrous fireproofing on structural steelwork, thermal insulation on heaters, boilers, pipes and other mechanical equipment, decorative or acoustic plaster finish on ceiling and walls, asbestos-cement products, including roof material acoustic paneling, electric insulation, laboratory table tops, water and sewage piping systems, ceiling tiles, vinyl floor tiles or sheet flooring.
In 1973 the spray application of asbestos insulation ceased when new regulation were implemented under the Ontario Construction Safety Act. Following the change suppliers of pipe and boiler insulation stopped using asbestos in their products. Both of these asbestos applications are prohibited by the new asbestos regulation (O Rag 654/85).
WHY IS ASBESTOS A HEALTH HAZARD?
Asbestos is a known hazardous material. Several diseases are associated with exposure to asbestos. They are asbestosis, mesothelioma, cancer of the lung and other asbestos related cancers. These are serious, debilitating diseases that often end in severe medical disability or death
To cause disease, asbestos fibres must be inhaled into the lungs. Fibres that can enter the lung and cause disease are too small to be visible to the naked eye. For each disease there is a period of latency that is usually more than ten years, between first exposure to asbestos and the appearance of the disease. It is this characteristic that makes asbestos disease so insidious. Exposure can continue for many years without any outward evidence of harm while the disease develops silently within.
ASBESTOS RELATED DISEASES
Asbestosis is a disease of the lungs caused by scar tissue forming around very small asbestos fibres deposited deep in the lungs. As the amount of scar tissue increases, the ability of lungs to expand and contract decreases, causing shortness of breath and a heavier workload on the heart. Ultimately, asbestosis can be fatal.
Mesothelioma is a relatively rare cancer of the lining of the chest and/or abdomen. While this disease is seldom observed in the general population, it appears frequently in workers exposed to asbestos.
Lung cancer appears quite frequently in people exposed to asbestos dust. While science and medicine have not yet been able to explain precisely why or how asbestos causes lung cancer, it is clear that exposure to asbestos dust can increase the risk of this disease. Studies have shown that the risk to asbestos workers is roughly five times greater than for people who are not exposed.
Cigarette smoking, another cause of lung cancer, multiplies the risk. Cigarette smoking and asbestos exposure combine to produce a synergistic effect. Research has shown that the risk of developing lung cancer was fifty times higher for asbestos workers, who smoked, than for workers who neither smoked nor worked with asbestos.
The relationship between asbestos exposure and asbestosis, mesothelioma and lung cancer has been clearly established and is beyond argument. Several other cancers have also been associated with the inhalation of asbestos. Although the evidence is inconclusive, these cancers should be noted. They are, gastrointestinal cancer affecting all sited in the gastrointestinal tract, and cancer of the larynx.
A number of less serious effects have been associated with asbestos exposure, such as pleural plaques, asbestos bodies and warts. Pleural plaques are areas of scarring of the pleural surfaces. In general, they are not associated with any functional abnormality and are merely and indicator of asbestos exposure. Occasionally, they can become so widespread that they restrict lung function. Asbestos bodies, also known as “Ferruginous bodies”, result when asbestos fibres become coated with a substance containing protein and iron. The asbestos bodies are not harmful and like pleural plaques, serve as evidence of asbestos exposure. Asbestos warts are harmless skin growths that occur when asbestos fibres penetrate the skin