Asbestos

Asbestos (Greek ????????: a-, "not"; sbestos, "extinguishable") describes any of a group of fibrous metamorphic minerals of the hydrous magnesium silicate variety. The name is derived for its historical use in lamp wicks; the resistance of asbestos to fire has long been exploited for a variety of purposes. It was used in fabrics such as Egyptian burial cloths and Charlemagne's tablecloth, which, according to legend, he threw in a fire to clean. Asbestos occurs naturally in many forms (see below); it is mined from metamorphic deposits.

Controversy

As with some other environmental prohibitions like DDT and CFCs, the movement to ban asbestos has many critics, some of whom claim either that the substance in question is not harmful, or that the ban does more harm than good http://spiderjohnson.com/asbestos.html.

Related Topics:
DDT - CFC

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Among the arguments around asbestos prohibition:

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• The view that the shuttle Challenger exploded because the maker of O-ring putty was pressured by the EPA into ceasing production of its more temperature-resistant, asbestos-laden putty, prompting replacement with an inferior putty, which had continual problems of a sort which could have caused the O-ring leak and subsequent explosion.
• The "Amphibole Hypothesis" states that Chrysotile asbestos is not as harmful as asbestos from the amphibole group. Several studies have been conducted which support this conclusion. Criticisms have been raised about the methodology used in these studies. Several other studies have been conducted which contradict the "Amphibole Hypothosis" http://www.cdc.gov/niosh/pdfs/97-162-d.pdf.
• Some countries, notably Canada, still use Chrysotile asbestos http://www.chrysotile.com/en/chrysotile/regulation/qc-gov.aspx. Canada has a significant economic interest in the mining of Chrysotile.
• The question of why asbestos is also banned in circumstances where inhalation is nearly impossible, such as when it's being included in sealed areas already dangerous to human beings, instead of simply when it might be used as insulation in a ventilated area, or other similar cases which actually expose it to people against their will.
• Critics argue that where asbestos has been banned, its roles were taken by products which are often either inferior, or far more expensive. They argue that this has a negative impact on society as a whole, which (especially if the previous arguments are true in whole or part) may be greater than the benefit of its removal.