Agent Name

Vermiculite

CAS Number

1318-00-9

Formula

Al.Fe.4H2-O.H-O.Mg.O3-Si.O

Major Category

Mineral Dusts

Category

Other Mineral Dusts

Description

A hydrated magnesium-iron-aluminum silicate that expands up to 20 times when heated to 1093 degrees C; [Hawley]

Sources/Uses

Used for insulating, fireproofing, soil conditioning, oil well drilling, packing, and absorbing various materials; Also used in concrete, plaster, animal feed, and as a filler in paint, rubber, and plastic; [Hawley] Vermiculite installed in the past as loose-fill insulation in attics should be considered to be contaminated with asbestos. [Reference #1]

Comments

Vermiculite ores are commonly contaminated with actinolite and tremolite (noncommercial asbestos fibers). A mine and mill in Libby, Montana was closed in 1990, but health surveys showed increased asbestos-related lung and pleural diseases in former millers and miners as well as in residents. Studies of workers exposed to vermiculite in South Carolina and South Africa did not show increased incidence of lung fibrosis and pleural thickening. [Rosenstock, p. 415]

Reference Link

NIOSH Topic: Vermiculite Exposure

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Processes

Industrial Processes with risk of exposure: