Awareness is the main defence against asbestos exposure

Decaying asbestos products at work or at home, could increase exposure to occupational levels. The risk lies in the size and shape of the particles, small enough to pass through some respirators, large enough to lodge and clog up between lung follicles.

Asbestos fibres could have serious health effects when inhaled. As exposure increases and more fibres are inhaled, so does the risk of developing an asbestos related disease. To lower the risk of developing disease, measures must be in place to raise awareness, to minimise exposure, and as a last resort, to find effective respirative personal protective equipment and to prevent accumulation of fibres in the lungs. Asbestos-related diseases are generally associated with exposure to high levels of unstable or degrading asbestos ore or products, over a long time. Studies on miners, and workers in factories and shipyards, have shown that high exposures to asbestos could lead to one of three serious diseases; " Asbestosis, involving lung scarring " Lung cancer " Mesothelioma, a rare cancer affecting lung linings. These diseases may not appear for as much as 20 to 40 years after exposure to asbestos. Although the evidence is less clear, there is some suggestion that cancers of the gastrointestinal tract may be associated with asbestos exposure. Other studies have shown that smoking increases the risk of disease. Smokers exposed to high levels of asbestos have a much greater chance of developing lung cancer than non smokers. Exposure to asbestos can result in other benign conditions such as pleural fibrosis, which is thickening of the lining of the lungs, pleural plaques, or skin warts. Respirator selection Selection of appropriate respirators is based on airborne concentrations of asbestos fibers, or on conditions of use. Half-mask air purifying respirators with HEPA filters must be provided for Class II and III jobs where there is no negative exposure assessment. Powered air purifying respirators must be provided instead of negative pressure respirators where an employee chooses to use it. Full face air respirators operated in pressure demand mode, and equipped with auxiliary positive pressure self contained breathing apparatus, are required for employees in regulated areas where Class I work is done, and for which a negative exposure assessment has not been produced. Class I work, for example, is removal of thermal system insulation (TSI) and surfacing asbestos containing materials .Class II work includes removal of wallboard, resilient flooring, roofing, and so on. Class III work is repair and maintenance where TSI and surfacing material are likely to be disturbed. Non-occupational exposure Asbestos specific diseases are almost always a result of occupational exposure to asbestos. Non-occupational exposure resulting in disease have been seen in family members living with asbestos workers, or people who have lived in the neighbourhood of asbestos plants. Asbestos fibres are naturally occurring and result in a natural background presence in the environment. This pollution, combined with widespread use of asbestos in products such as vehicle brake linings, means that we are all exposed to small amounts of asbestos in our daily lives. It is not this very low level of exposure that results in asbestos disease, but higher levels of occupational exposure that are of concern to most authorities. Studies have not shown evidence of asbestos-specific disease of individuals who breathe asbestos in outdoor air, or who inhale asbestos as occupants of asbestos-containing buildings. Still, proper measures for preventing or minimising exposure to asbestos must be present in every workplace, public space, and home. Reference; University of Toronto; Environmental Health and Safety * Gilbert Dekenah is managing member of the HS&E consultant, SHIP.

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