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There are six forms of Asbestos although only three are commonly used, these are Chrysotile (white asbestos), the most common; Amosite (brown asbestos) which can often be found in ceiling tiles and as a fire retardant in thermal insulation products; Crocidolite (blue asbestos), commonly used in high temperature applications. [9]
Asbestos (/ æ s ˈ b ɛ s t ə s, æ z-,-t ɒ s / ass-BES-təs, az-, -toss) [1] is a group of naturally occurring, toxic, carcinogenic and fibrous silicate minerals.There are six types, all of which are composed of long and thin fibrous crystals, each fibre (particulate with length substantially greater than width) [2] being composed of many microscopic "fibrils" that can be released into ...
The use of White Asbestos was banned in England, Scotland and Wales in 1999 by The Asbestos (Prohibitions) (Amendment) Regulations 1999. [61] Asbestos was banned in Northern Ireland in 2000 by the Asbestos (Prohibitions) (Amendment) Regulations (Northern Ireland) 2000. [62]
The most common asbestiform mineral is chrysotile, commonly called "white asbestos", a magnesium phyllosilicate part of the serpentine group. Other asbestiform minerals include riebeckite, an amphibole whose fibrous form is known as crocidolite or "blue asbestos", and brown asbestos, a cummingtonite-grunerite solid solution series.
Three polytypes of chrysotile are known. [8] These are very difficult to distinguish in hand specimens, and polarized light microscopy [6] must normally be used. Some older publications refer to chrysotile as a group of minerals—the three polytypes listed below, and sometimes pecoraite as well—but the 2006 recommendations of the International Mineralogical Association prefer to treat it as ...
Chrysotile asbestos, also known as white asbestos, was first commercially mined at the Havelock Mine in 1939 [3] after detailed prospecting from 1928 to 1929. [4] Mining and processing methods included dry grinding, which, together with the crushing, sorting, grinding and bagging of the ore, generated substantial dust at the mine site and in the surrounding area.
In 1935, officials of Johns-Manville and Raybestos-Manhattan instructed the editor of Asbestos magazine to publish nothing about asbestosis. [42] In 1936, a group of asbestos companies agreed to sponsor research on the health effects of asbestos dust, but required that the companies maintain complete control over the disclosure of the results. [41]
Pleural contamination with asbestos or other mineral fibers has been shown to cause cancer. Long thin asbestos fibers (blue asbestos, amphibole fibers) are more potent carcinogens than "feathery fibers" (chrysotile or white asbestos fibers). [28] However, there is now evidence that smaller particles may be more dangerous than the larger fibers.