These products consist of asbestos up to 90% in loosely bound form. Such applications exposed workers to uncontrolled inhalation of loose asbestos dust in high concentrations which led to health related problems. Otherwise, amphibole asbestos fibers like crocidolite and amosite were used uncontrolled in manufacturing fibre – cement. Until 1980’s, all kinds of amphibole asbestos banned strictly all over the world because of their harzadous. Once the ill effects of such applications were realized these were prohibited in these countries. However, old installations, some of them deteriorating with time are a matter of concern to them, bearing in mind that the buildings are closed and have no natural ventilation.
|Products||Abestos cement||Chrysotile cement|
|Low density||High density|
This situation does not apply to Vietnam, where warm climatic conditions with high humidity do not require the use of such insulation products in the buildings. In Vietnam, we only use Chrysotile asbestos fibre for the manufacture of asbestos-cement sheets and asbestos-cement pipes which contain a very small quantity of Chrysotile fibre (only 8 –10%) and balance raw material used is cement 55%, fly ash 30 –35%. The chrysotile fibres are firmly locked-in or encapsulated within the cement matrix during manufacture so that fibres cannot be emitted into the atmosphere under normal use and thus, poses no health risk to the general public or environment. Several studies abroad have concluded that use of Chrysotile in the manufacture of Asbestos Cement Products under controlled conditions is safe for the workers, environment and the general public.
All the member industries of chrysotile asbestos cement products manufacturers carry out dust concentration measurements and health surveillance programs as prescribed by regulatory authorities. The dust concentrations measured in various departments of twelve factories were less than 0.13 fibre/ml of air 620 randomly selected employees of these factories were medically screened for asbestos related diseases. No asbestos related diseases were detected in these employees who are exposed to chrysotile fibre for the last 5-20 years.