Asbestos is an inert material and is not toxic to touch, smell or ingestion. Asbestos fibre can be an occupational health hazard only when its dust is respirable and becomes airborne and when such a dust is inhaled in excessive amounts, usually over a prolonged period. Asbestos fibre is not a hazard when proper dust control procedures are in operation. Stray or short casual exposure to asbestos dust involves no measurable risk.

Health risk at a workplace due to inhalation of respirable dust is not peculiar to asbestos fibre. Asbestos is but one of many such fibres. Virtually all respirable materials are potential health risks when used in uncontrolled conditions.

Health risks associated with uncontrolled use of Asbestos

Asbestosis - This is a form of pneumoconiosis that reduces lung capacity. Pneumoconiotic diseases are caused by prolonged inhalation of high levels of mineral, metal or plant dusts, well known examples being iron, silica, coal, cotton, beryllium and asbestos. In the case of asbestos, the disease is called 'Asbestosis'.(1)

Lung Cancer - People, who develop asbestosis, run the risk of contracting this disease. This risk is greatly increased in those workers who smoke.(2,3) Studies show that for non-smokers exposed to low level asbestos dust there is no increased risk of contracting lung cancer.

Mesothelioma - A rare type of cancer which affected the inner lining of the chest wall or abdominal cavity. It was reported in workers exposed to loose dust in high concentrations of Crocidolite (Blue) and Amosite (Brown) varieties of amphibole asbestos. In the West during the period of ignorance asbestos in loose form was extensively sprayed on ceilings and structure to conserve heat. (4) Medical reports do not attribute this disease to the use of Chrysotile (white) asbestos fibres.(5)

It should be noted that above diseases were the result of the use of asbestos under entirely uncontrolled conditions in the past when the harmful effects of asbestos were not known and understood. In today's well controlled and regulated industrial plants, occurrence of such diseases should not arise.

Indian Experience

Permissible Exposure Limit Value (PELV) - As technology has advanced the exposure to workers in the manufacturing process is kept well below the Permissible Exposure Value (PEV) of 1 f/cc as stipulated by the Ministry of Labour in the Factories Act.

Use of Crocidolite - The import of Crocidolite (Blue fibre) which is known to have caused mesothelioma in the West has been banned in 1993. Only Chrysotile (white) variety is being imported and used for the manufacture of asbestos-cement products.

DGFASLI Studies - During 2004 & 2005 Directorate General Factory Advice Services and Labour Institutes (DGFASLI) undertook studies on "Health Status of Workers in the Asbestos Industry" and "Status of Work Environment in Asbestos Products Manufacturing Industry".

These studies covered 9 units manufacturing A.C.products using Chrysotile fibre in the manufacturing process. A total of 702 workers in the age group of 20 to 50 years were covered. The studies conclude that the workplace emission levels in A.C.Industries are well below the stipulated levels of emission, ie, 1 f/cc( 6) and that no case of asbestosis was detected during the study(7).

References:

• Gaensler EA, Asbestos-Related Disorders - Clinical and Epidemiological Aspects, Proceedingsof the Fleischner Society Eighteenth Annual Symposium on Chest Disease. Montreal 1988,17-31.
• Doll R. Mortality from Lung Cancer in Asbestos Workers. British Journalof Industrial Medicine, 1985, 12:81
• Berry G.Newhouse ML.Turok M; combined Effects of Asbestos Exposures and Smoking on Mortality from Lung Cancer in Factory Workers. Lancet 1972, 2:476
• Wagner J.C. et al, British Journal of Industrial Medicine 45: 305-308 (1988).
• Peter Elmes; Mesotheliomas and Chrysotile; The Annals of Occupational Hygiene Vol.38, No.4, August 1994, 547-553
• The National Study on Status of Work Environment in Asbestos Products Manufacturing Industry, 2005.
• The National Study on Status of Workers in the Asbestos Industry, 2004.