Current asbestos products are as different from the old ones as night and day. Today, only one type of asbestos is offered: chrysotile. In addition, the industry now only markets dense and non-friable materials in which the chrysotile fibre is encapsulated in a matrix of either cement or resin. These modern products include chrysotile-cement building materials, friction materials, gaskets and certain plastics. The old products, principally low-density insulation materials, were very dusty and crumbled under hand pressure. Unlike today's products, they often contained amphibole fibres (crocidolite and amosite).
Chrysotile: controlled use = safety
There is more scientific evidence showing that asbestos-induced lung cancer, like fibrosis (asbestosis), is a threshold phenomenon. Moreover, studies confirms that very few cases of mesothelioma have been reliably attributed to chrysotile, despite the many thousands of workers who in the past have had massive and prolonged exposures. Mesotheliomas linked to exposure to asbestos are associated with amphibole fibres.
It is now known that in modern chrysotile manufacturing plants, at today's dust levels (0,5 to 1,0 fibres per mililitre) the risks, if any, are so low as to be undetectable. This is what is called a practical threshold.
Chrysotile-cement: a safe, high-quality product
Chrysotile-cement is valued principally for its excellent cost effectiveness and durability. Manufacture of this material requires the import of only small quantities of fibre, the other raw materials (portland cement, water) being easily available locally. Moreover, the manufacturing technology requires little investment and consumes less energy than production methods for competing products.
According to a group of experts convened by the World Health Organization (WHO - Oxford, 1989), chrysotile-cement products do not present risks of any significance to public health or the environment. Moreover, workers in this industry, whether employed in the manufacture, installation or removal of materials, are not exposed to any detectable risk when effective prevention and control measures are applied.
Why the controversy?
The real problem: old, poorly controlled products
Because of the latency period between massive exposure and the appearance of diseases, it will take many more years before we see the health benefits of the prohibition of amphiboles and friable asbestos products which began in the 70's and of the regulations which now impose strict factory controls.
Do in-place friable asbestos insulation materials pose a threat to public health?
However, management programmes, which include inspections and corrective measures whenever necessary, are recommended for buildings containing asbestos insulation materials. Moreover, all maintenance workers must have access to adequate safety equipment and receive intensive training and information programs to ensure correct work practices are followed when handling these materials. Removal of asbestos insulation should be considered a measure of last resort, and undertaken only when the material is beyond repair or at the time of major renovation work or building demolition.
Asbestos removal = danger
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