RESOURCES

http://www.who.int/ipcs/assessment/public_health/asbestos_recent/en/

Asbestos

Asbestos is the category of minerals present in nature as bundles of fibres that can be mined and then separated into thin, durable threads. These fibres are resistant to heat, chemicals, and fire, and do not conduct electricity. Therefore, asbestos fibres are commonly used for a variety of manufactured goods, including roofing, ceiling and floor tiles, paper and cement products, textiles, and coatings. Asbestos is classified into two major groups: serpentine asbestos (which have long, curly fibres that can be woven) and amphibole asbestos (which have straight, needle-like fibres that are more brittle and less able to be woven).[1] Asbestos fibre can continue to be subdivided up to molecular dimensions. This property results from the molecular structure in which the units are linked together more strongly in one direction. Thickness can thus go down to between 100 and 1000 Armstrong units which is beyond the resolution of optical microscopes. So dust-counting methods will either miss these fibers or under-report as they are seeing only the fewer larger ones. Another property is the tendency for an individual fiber to sub-divide further, particularly at the ends, thereby forming “parachutes” that will stay aloft in air [5].

Dangers

When products containing asbestos are disturbed, tiny asbestos fibers are released into the air. Due to its small dimensions, inhaled asbestos dust can penetrate cell walls in the lining of lungs and interfere with cell functions. These malfunctions take various forms. The inflammation from a single fibre could do real damage which may not be seen for 20 years or more. Therefore, the minimum safe exposure is zero. The three major health effects of asbestos exposure are:

  1. Asbestosis: a progressive, non-cancerous disease of the lungs. Asbestos fibers scar the respiratory tissues, making it more difficult for oxygen to enter the bloodstream. Symptoms include shortness of breath and a dry, crackling sound when inhaling. There are no effective treatments for asbestosis.[2]
  2. Lung cancer: a malignant tumor that invades and then obstructs the air passages in the lungs. Scientists believe that asbestos fibers kill cells, but while doing so, the dying cells release a protein (high-mobility group box 1 protein, HMGB1) that triggers the release of mutagens and growth factors that cause tumor formation.[3] Symptoms of lung cancer include coughing, difficulty breathing, shortness of breath, persistent chest pains, hoarseness, and anemia. People working in the milling, asbestos manufacturing, and mining industries have a higher risk of developing lung cancer than do people in other industries.[4]
  3. Mesothelioma: a rare form of cancer found in the membrane (thin lining) of the lung, chest, abdomen, and heart. Most mesotheliomas have been linked to asbestos exposure.
    lung-cancer-risk-asbestos-bihar

After studies showing the carcinogenic nature of asbestos, the Environmental Protection Agency in USA banned its use in 1989. Many countries have also banned asbestos use.

[1]National Cancer Institute. “Asbestos Exposure and Cancer Risk.” www.cancer.gov. National Institutes of Health. Web. 01 June 2012.
[2] EPA. “Asbestos: Basic Information.” www.epa.gov. Environmental Protection Agency, 25 May 2012. Web. 01 June 2012.
[3] Yang H., Rivera Z., Jube S., Nasu M., Bertino P., Goparaju C., Franzoso G., Lotze M. T., Krausz T., Pass H. I., Bianchi M. E., Carbone M. (2010). Programmed necrosis induced by asbestos in human mesothelial cells causes high-mobility group box 1 protein release and resultant inflammation. Proc. Natl. Acad. Sci. U.S.A. 107, 12611–12616. doi: 10.1073/pnas.0913004107.
[4] EPA. “Asbestos: Basic Information.” www.epa.gov. Environmental Protection Agency, 25 May 2012. Web. 01 June 2012.
[5] THE PHYSICAL AND MOLECULAR STRUCTURE OF ASBESTOS, Richard Gaze, Annals of the New York Academy of Sciences , Vol.132(1)pp. 23-30, Dec. 2006]

Asbestos Cemet Products

There are several kinds of Asbestos depending on the chemical structure. Of these there is one called white asbestos or Chrysotile, the most flexible

chrysotile-asbestos

and widely used of all asbestos fibres; they can also withstand the fiercest heat. Resistance to alkaline attack makes Chrysotile a useful reinforcing material in asbestos-cement building products. Why? Like the other forms of asbestos, Chrysotile can absorb organic materials such as resins and polymers and can be used to strengthen particulates such as cement. Chrysotile also tends to age better than other forms of asbestos. Couple this with the fact that it is the most occurring asbestos form, 95% of the asbestos mined is Chrysotile.

Asbestos Brake Pads

In recent years, the number of automobiles on Indian roads has been increasing at a high rate, and there is little prospect of the slowdown of the rate of growth. But many of the cars use asbestos brake pads. This puts those mechanics who replace the pads at great risk. The public is also breathing the asbestos dust produced from breaking.

brake pads

Other Asbestos Products

There are many asbestos articles such as pipes, wall filler compounds, and so on. There is no effective federal government control on the manufacturing of these products.

Who Is Affected

The people most affected are the hundreds of thousands of people involved in mining and manufacturing and their families – the families are affected because the workers generally bring what they wear home.