Vermiculite insulation is a shiny, mica-like mineral that expands when heated and is used as a thermal insulator. It is lightweight and has found its way into many different types of products. Until 1990, however, much of the supply of mined vermiculite was contaminated with asbestos.
From 1919 to 1990, a single vermiculite mine in Montana produced over 70 percent of the vermiculite sold in the United States. Unfortunately, that mine also contained asbestos, which contaminated the minerals produced there. Many homes that were built in the 20th century contained contaminated vermiculite, exposing the inhabitants to asbestos and increasing the risk of cancer.
Asbestos is a family of minerals that appear in nature as bundles of fibers. When disturbed, these fibers can become airborne, and inhaling them can cause the fibers to lodge inside the lungs. Exposure to asbestos increases the chances of lung cancer, pleurisy, mesothelioma and other life-threatening conditions.
The Environmental Protection Agency recommends that homeowners avoid areas with exposed vermiculite insulation in order to prevent any disturbance that might cause asbestos fibers to become airborne. Items should not be stored in areas with vermiculite present, and only a licensed asbestos contractor should attempt to remove the insulation or perform remodeling in any area around vermiculite insulation.