USA The US Environmental Protection Agency (EPA) has announced a blanket ban on all forms/types of the deadly carcinogen ‘asbestos’.
Asbestos
- Asbestos is a general term for a group of six silicate minerals with similar but distinct properties.
- It is a soft and hairy substance made of microscopic fibers whose fibers are sharp and needle-like.
- It is divided into two sub-groups ‘serpentine’ and ‘amphibole’ in which the only serpentine asbestos ‘chrysotile or white asbestos’ is most used.
- It has been widely used in many construction and fireproof products and machinery parts.
Physical properties
- It is heat and corrosion resistant.
- It is highly flexible, strong and durable.
- It is not flammable even at very high temperatures.
- It has low thermal conductivity and high resistance to electricity.
Health effects
- According to the World Health Organization (WHO), exposure to asbestos can cause a number of serious diseases in humans, including mesothelioma, laryngeal cancer, ovarian cancer, lung cancer and asbestosis (a lung fibrosis-like condition).
- When asbestos-containing products are used, microscopic asbestos fibers become airborne and can be inhaled into the lungs and remain there for a long time.
- Asbestos is banned in 55 countries of the world, but till now its import and use was continuing in America. Despite the ban, the risk of exposure to asbestos from past uses remains.
Sources of asbestos reserves
- Naturally occurring asbestos deposits exist throughout the world.
- States along the West and East coasts of the United States have the largest asbestos reserves.
- India’s asbestos requirement is met through imports from Russia, Kazakhstan, Brazil and China.
White asbestos
- White asbestos also called chrysotile is the most common form of asbestos.
- It is a soft, fibrous silicate mineral in the serpentine subgroup of phyllosilicates. Its chemical formula is Mg3(Si2O)(OH)4.
- Chrysotile asbestos was used primarily in the chlor-alkali industry, which produced chlorine bleach, caustic soda and other chemicals used in water treatment.
- However, chrysotile asbestos diaphragms, safer alternatives to filters used in chlorine production, have been available for some time.
- Its physical properties make it desirable for inclusion in construction materials, but it poses serious health risks when dispersed in the air and inhaled.
- This was the last asbestos type to be legally used in the US.
- Since 2005, all asbestos products have been banned in all EU countries, including the member states of Eastern Europe.