Typical test results of air sampling show that fibre concentration is around 0.07 fibre/cc during cutting and installation of chrysotile cement roofing sheets. This is far below the level of 0.5 fibre/cc envisaged. There will be no risk for workmen or carpenters if they follow properly recommended work practices while installing or fixing roofing sheets.
Thai manufacturers follow recommendations from the Ministry of Industry and Ministry of Public Health. They provide health check-up and lung x-ray for all employees annually. There is no evidence regarding the disease up to date.
Most manufacturers have invested in large and efficient dust control equipment in the factories for the safety of operators and worke
Asbestos has been an essential component of automotive friction materials for more than 70 years; and only chrysotile asbestos is used for industrial purpose. Its typical proportion ranges from 25% to 65% by weight. Chrysotile enforces strength, flexibility, heat resistance to brake linings, in addition to friction and wear properties.
Asbestos fibres have been present in the general environmental air long before human’s exploitation of the mineral. This is due to the natural erosion from geological formations which are quite common across the world. The total amount of asbestos emitted from natural sources is much greater than that emitted from industrial sources.
Because of inherent properties of chrysotile fibre and cement, chrysotile cement sheets do not decay or rot. They do not crumble despite continued exposure to environmental elements or age. There is no evidence that people living under chrysotile cement roof, or the general public living around asbestos cement-roofed buildings or factories producing asbestos cement products have been specifically affected in any manner.
Conducting an experiment to test this proposition is not feasible. It is virtually impossible to challenge cells, tissues or whole animals to one single fibre due to the ubiquity of asbestos fibres. One milligram of asbestos alone may contain several hundred million respirable fibres. Furthermore, experimental protocols call for a minimum dose of several hundred thousands of fibres in order to induce observable effects.
The use of asbestos-cement (A/C) pipes is dated back to the early 1920s. It is estimated that by the end of the 1980s, nearly 3 million kilometres of pipes would have been laid worldwide to transfer potable water.
There is no risk, whatsoever, for people who live or work under chrysotile cement roof. Chrysotile fibres are locked-in and bound with cement. It is not possible for the fibres to escape from the products into the ambient air.
Dusts or airborne fibres including glass fibre, synthetic fibre, chrysotile fibre, stone dust, gasoline fume, exhaust fume, all are dangerous, if workers inhale and are exposed to them for a long period of time. However, the processing of chrysotile fibre as a raw material in manufacturing factories is properly controlled and thus, poses no risks to workers. Once the fibres are covered by cementous slurry, they are locked-in permanently and cannot escape.
This alarmist figure is far from reality. The estimated number of deaths connected to all types of asbestos, regularly advanced by ban asbestos groups is based on the model of Peton
It is important to use solid science to guide our decisions in matters such as this. The chrysotile industry has a responsibility to promote its safe use.