Asbestos Risk in Vermiculite

Vermiculite has been widely used as an insulation material, a lightweight aggregate in concrete and plaster, a soil conditioner, and a carrier for fertilizers and other chemicals. It is used in an expanded or

exfoliated form—the raw micaceous vermiculite flakes are rapidly heated, thus vaporizing water between the mica layers and producing accordianlike or wormlike particles. The product is chemically inert, fire resistant, and odorless. In 1998, the U.S. produced roughly 170,000 metric tons of exfoliated vermiculite, with a market value of $53 million.