Properties and uses of asbestos have been recognized from the time of ancient civilizations. Ancient civilizations have recognized the heat and combustion resistant properties of asbestos. The dangers associated with exposure to asbestos were not well recognized until 19th century. Pliny has observed that asbestos miners are less healthy than other slaves. The industrial revolution that has occurred during the 18th and 19the centuries has greatly increased the demand for materials like asbestos that are heat and combustion resistant for machines and power generators (Ref 1).
Joseph Lieutaud has described two cases of probable mesothelioma in a study of 3,000 autopsies in 1767, and E. Wagner has described mesothelioma as a pathological entity 1870. Despite all this the existence of malignant mesothelioma as a distinct clinical entity was debated until early part of 19th century. [Ref 2, 3]Occurrence of scarring in the lungs, progressive deterioration of health and subsequent death from respiratory failure was noted asbestos miners as early as 1898 (Ref 4). Late 18th century and early 19th century was the era of tuberculosis infection and it was difficult to distinguish the lung scarring caused by asbestos exposure from those caused by tuberculosis with techniques available at that time. Subsequently most of these lung scarrings from asbestos exposure were attributed to tuberculosis and other respiratory infections which were rampant at that time. A casual relationship of lung scarring and asbestos was not made until 1930 even then the entity of malignant mesothelioma as a separate clinical entity was not well recognized.
Then came the two world wars, and this has substantially increased the demand and use of asbestos and asbestos mining. During this period asbestos was widely used in ships, building and combat equipments. Asbestos was cheap and had heat and combustion properties and fitted in with the requirements for many civilian uses. Asbestos soon found many useful venues in the civilian population and consumer goods. At this time asbestos was widely used in civilian building, construction industry. Asbestos was used to build many schools, homes and public buildings. Merewthers and Price at London Chest Hospital were the first to firmly establish the relationship between lung scarring in asbestos-miners and exposure asbestos (Ref 5).
Once the dangers of asbestos exposure were recognized, various legal proceedings followed aimed at minimizing the risks of asbestos exposure. Limits were placed on the maximum allowable industrial exposure to asbestos in England. Such legal proceedings occurred through out the world. Increased incidence of lung cancer in patients with asbestosis was soon recognized, case reports to this effect appeared in journals as early as 1935. In 1955 Doll reported (Ref 6) a case controlled study that has firmly established the relationship between asbestos and lung cancer. Regulations soon followed which were aimed at complete elimination of asbestos exposure and asbestos completely disappeared from its previous widespread use in the shipping and building industry. During the peak period of use of asbestos several thousand Americans were occupationally exposed to asbestos. The exact number of Americans exposed to asbestos is unknown, however reasonable estimates show that between 1940 and 1979, approximately 27.5 million people were occupationally exposed to asbestos in the United States. Calculated annual death rate from mesothelioma of about 2,000 in 1980 up to 3,000 in the late 1990s (Ref 7). Workers may have been exposed to asbestos through asbestos mining or milling industry or by working in an environment that uses asbestos like shipping and construction industry. Even today asbestos is not completely eliminated from America. Asbestos is present in many private and public buildings in the United States. Ten to fifteen percent of schools in the United States still retain asbestos that was placed between 1946 and 1972. Public health hazards associated with exposure in such circumstances, and the cost benefit equation required to completely replace all these structures are still unclear despite numerous arguments on both sides (Ref 8). Studies have suggested that even such incidental minor exposure may be risky. Experience with school teachers who have developed mesothelioma who had no other asbestos exposure causes concern in this regard especially about children, who may not develop any symptoms or signs for several years.
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2. Selikoff IJ, Lee DHK. Asbestos and disease. New York, NY: Academic; 1978.
3. Semb G. Diffuse malignant pleural mesothelioma. A clinicopathological study of 10 fatal cases. Acta Chir Scand 1963;126:78.
4. Women Inspectors of Factories. Annual report for 1898. Her Majesty's Stationery Office, London, 1899.
5. Merewether ERA, Price CV. Report on effects of asbestos dust in the lungs and dust suppression in the asbestos industry. Her Majesty's Stationery Office, London, 1930.
6. Doll R. Morality from lung cancer in asbestos workers. BJM 1955;12:81.
7. Nicholson WJ, Perkel G, Selikoff IJ. Occupational exposure to asbestos: population at risk and projected mortality-1980-2030. Am J Indust Med 1982;3:259.
8. Mossman BT, Bignon J, Corn M, et al. Asbestos: scientific developments and implications for public policy. Science 1990;247:294.