Asbestos

Abstract The term asbestos is a generic designation referring usually to six types of naturally occurring mineral fibers that are or have been commercially exploited. These fibers belong to two mineral groups: serpentines and amphiboles. The serpentine group is represented by a single asbestiform variety‐chrysotile. There also are five commercial asbestiform varieties of amphiboles‐anthophyllite asbestos, cummingtonite‐grunerite asbestos (amosite), riebeckite asbestos (crocidolite), tremolite asbestos, and actinolite asbestos. Amosite and crocidolite are no longer mined. Nearly all of the asbestos mined after the mid‐1990s was chrysotile. Only very small amounts of actinolite, anthophyllite, and tremolite asbestos may be mined in a few countries. Asbestos was mined in Argentina, Brazil, Canada, China, India, Kazakhstan, and Russia in 2010; world production was estimated to be 1.97 × 10 6 tons. Properties that made asbestos valuable for industrial applications were their thermal, electrical, and sound insulation properties; inflammability; matrix reinforcement (cement, plastic, and resins); adsorption capacity (filtration, liquid sterilization); wear and friction properties (friction materials such as brakes and clutches); and chemical inertia (except in acids). These properties led to the use of asbestos in about 3,000 products by the 1960s. Since about 1995, asbestos‐cement products, including pipe and sheets, accounted for more than 95% of global asbestos consumption as other uses of asbestos have declined. Global consumption of asbestos was estimated to have been about 1.98 × 10 6 tons in 2009. The leading consuming countries in 2009 were Brazil, China, India, Russia, and Thailand, each with more than 100,000 tons of consumption.