Asbestos
Asbestos is a set of six
naturally
occurring silicate minerals used
commercially for their desirable
physical
properties. They all have in common
their eponymous, asbestiform habit:
long (ca. 1:20 aspect ratio), thin
fibrous crystals. The prolonged
inhalation
of asbestos fibers can cause serious
illnesses including malignant lung
cancer, mesothelioma, and asbestosis (a
type of pneumoconiosis). The European
Union has banned all use of asbestos and
extraction, manufacture and processing
of asbestos products.
Asbestos became increasingly
popular among manufacturers and builders
in the late 19th century because
of its sound absorption, average tensile
strength, its resistance to fire,
heat, electrical and chemical damage,
and affordability. It was used in
such applications as electrical
insulation for hotplate wiring and in
building
insulation. When asbestos is used for
its resistance to fire or heat, the
fibers are often mixed with cement
(resulting in fiber cement) or woven
into fabric or mats.
Asbestos mining began more
than
4,000 years ago, but did not start
large-scale until the end of the 19th
century. For a long time, the world's
largest asbestos mine was the Jeffrey
mine in the town of Asbestos, Quebec.
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