Dear Editor,
Asbestos is a term for several different mineral silicates that exist in fibrous form.It is mined in a number of countries and has been known and used since ancient times.
It was used extensively between 1940 and the 1970s in more than 3,000 products, including thermal, acoustic, and electric insulation, in fire-proofing materials, in floor, tile, roof and cement products, and in friction materials such as automobile brake shoe lining.
The most commonly used type of asbestos is chrysotile which until the end of the 1970s was extensively used in combination with amphiboles in the production of building materials in many countries like Guyana.
In the Caribbean, where no mining or manufacturing of asbestos containing products takes place, most of the imported asbestos containing material is seen in the form of asbestos cement corrugated roof sheets, insulation materials in connection with boilers and steam pipes, and brake shoe linings.
While the use of asbestos for roofing and insulation has been stopped, it is still used in automobile brakes.
Asbestos materials that are intact and undamaged are not considered hazardous. To pose a threat, the fibers have to become airborne and, therefore, respirable.
The latency period for asbestos associated pulmonary diseases is usually 20-30 years or longer. However, the latent period for mesotheliomas can be as short as 7-8 years after initial exposure.
No safe threshold limits have been scientifically proven for asbestos exposure.In recent years, however, the majority of industrialized countries have adopted an occupational exposure limit of 1 fibre/ml as the maximum permissible average concentration levels for chrysotile.
Asbestosis is a scarring disease of the lung that causes shortness of breath. The disease is associated with high exposure and can progress in the absence of continued exposure.
cancers of the lung are most frequently associated with asbestos. it should be noted, however, that cigarette smoking greatly increases the risk of lung cancer in persons exposed to asbestos.
Pleural scarring of the lining of the lung or chest wall is generally associated with extensive exposures, but can also occur at levels lower than those required to produce asbestosis.
It is associated with impairment of lung function, especially when extensive.
Yours faithfully,
Mohamed Khan
