The U.S. Environmental Protection Agency recommends that homeowners not try to remove vermiculite insulation themselves. If the insulation is inside walls or an attic where it is not likely to be disturbed, leave it alone. If renovations are planned, the vermiculite should be removed by a professional asbestos contractor.
Most vermiculite used in home insulation between 1919 and 1990 came from a single mine in Montana known as the Libby mine. The Libby mine also contained a large deposit of asbestos that contaminated the mined vermiculite. Loose-fill vermiculite insulation from the Libby mine was marketed in the United States and Canada as Zonolite. Spray-on vermiculite from the mine was sold under the brand name Monokote. The EPA says that any home insulated with vermiculite prior to 1990 probably contains contaminated vermiculite and should be treated with appropriate caution.
Vermiculite is a weathered mica clay that expands when heated. Vermiculite is soft, lightweight, translucent and pliable. Colors of the mineral range from yellowish white to light brown. Exfoliated vermiculite is used to make fireproof panels, brake linings, potting media, animal substrate and absorbent packing material. Mixed with Portland cement, vermiculite is also used as a base for vinyl swimming pool liners.