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Asbestos (Greek a-, "not"; sbestos, "extinguishable") is a group of fibrous metamorphic minerals. The name is derived for its historical use in lamp wick s. It was also used in fabrics such as Egyptian burial cloths and Charlemagne's tablecloth, which, according to legend, he threw in a fire to clean. The fibers are typically mixed with cement or woven into fabric or mats. It is used in buildings for its flame-retardant and insulating properties, its tensile strength, flexibility, and resistance to chemicals. Asbestos is now known to be carcinogenic and is banned in many countries.
Most asbestos fibers are invisible to the unaided human eye because their size is about 3.0-20.0 µm.
Confusingly, the Modern Greek word asbestos means quicklime.
Notes: Serpentine rocks are those with curled fibres. AmphiboleHornblende) Amphibole defines an important group of dark-colored rock-forming silicate minerals composed of double chain SiO tetrahedra linked at the vertices and generally containing ions of iron and/ or magnesium in their structures. In chemical composis have straight, needle-like fibres.
The amphiboles, in their fibrous form, are friable and therefore the most carcinogenic, although they also exist in safer non-fibrous forms.
Other asbestos minerals, such as tremolite, actinoliteThere is also a community named Actinolite,_Ontario in Canada. metadiabase intrudes light granitic gneiss Actinolite is an inosilicate mineral with the chemical formula Ca(MgFe)SiO(OH) Mineralogy Actinolite is an intermediate member in a series between tr and anthophyllite are not used industrially but occur in traces.
Strong concerns about the health hazards associated with asbestos had been described many times over the years. As early as 1898 the Chief Inspector of Factories of the United Kingdom reported to the Parliament in his Annual Report about the "evil effects of asbestos dust". He reported the "sharp, glass like nature of the particles" when allowed to remain in the air in any quantity, "have been found to be injurious, as might have been expected" (Report of the Select Committee 1994). In 1906 a British Parliamentary Commission confirmed the first cases of asbestos deaths in factories in Britain and recommended better ventilation and other safety measures. In 1918 an American insurance company produced a study showing premature deaths in the asbestos industry in the United States and in 1926 the Massachusetts Industrial Accidents Board processed the first successful compensation claim by a sick asbestos worker.
The fine asbestos fibres are easily inhaled, and can cause a number of respiratory complaints, including a potentially serious lung fibrosis called asbestosisAsbestosis is a chronic inflammatory medical condition affecting the parenchymal tissue of the lungs. Causes and presentation It is caused by long-term inhalation of asbestos fibers. People with occupational exposure to the mining, manufacturing, handling. Exposure to asbestos has also been determined to cause a very serious form of cancerFor other meanings of Cancer: see Cancer (disambiguation . apoptosis; cancer cells, however, avoid apoptosis. Cancer is a group of related diseases characterized by uncontrolled cell division. Currently, it is believed that cancers arise from both genetic, mesotheliomaMesothelioma is an uncommon form of cancer, usually associated with prolonged exposure to asbestos, which affects the pleura, a sac which surrounds the lungs, the peritoneum, the lining of the abdominal cavity, or the pericardium, a sac that surrounds the, that occurs in the chest and abdominal cavities. This aggressive disease is not properly referred to as a lungThe lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. Its function is to exchange oxygen from air with carbon dioxide from blood. The process in which this happens is called " exte cancer, as the malignant cells are derived from the mesothelium, a tissue found on the inner walls of the chest and abdominal cavities and on the outer surface of the lungs rather than in the lung itself.
Asbestos is carcinogenic. In the United States alone, it is estimated that ten thousand people die each year of asbestos-related diseases, such as mesothelioma, asbestosis, lung cancer, and gastrointestinal cancer. Asbestos has a synergistic effect with tobacco smoking in the causation of lung cancer. In the United States, asbestos was one of the first hazardous air pollutants regulated under Section 112 of the Clean Air Act of 1970.
In mid-2004, a huge public outcry across Australia followed revelations at a New South Wales government-sanctioned inquiry into the company James Hardie's handling of its asbestos injury liabilities. See that article for details.
See also: List of minerals, Eternit, Vermiculite
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