Vermiculite is a mica-like mineral mined around the world and used in a variety of commercial and consumer products from 1919 to 1990. Vermiculite is a lightweight, odorless and fire-resistant material that has been used in numerous applications, such as insulation for attics and walls.
Not all vermiculite produced before 1990 contains asbestos fibres. However, to be safe and in the absence of evidence to the contrary, it is reasonable to assume that if your building has older vermiculite-based insulation, it may contain some asbestos. Although the overall percentages of asbestos in bulk vermiculite are very low, the airborne percentages can increase if the material is disturbed. Asbestos poses health risks only when fibres are present in the air that people breathe.
Exposure to asbestos can result in lung cancer, mesothelioma, inflammation of the chest cavity, and a scarring disease of the lungs known as asbestosis. The risk of contracting these diseases generally increases with the duration and intensity of exposure to asbestos, and smokers may face an even greater risk of lung cancer.
Vermiculite insulation is a pebble-like or rectangular, chunky product about the size of a pencil eraser, and usually gray-brown or silver-gold in color. Inspectors should be on guard for empty bags in the attic that bear the name Zonolite®, as this was the commercial name for vermiculite mined in the notorious Libby mine.
Never disturb vermiculite or any asbestos insulation. These products must be airborne to cause a health risk through inhalation, which most likely happens when they are removed or handled. The following are some additional tips with vermiculite issues:
In summary, vermiculite is a potentially hazardous mineral used as an insulator in buildings, but its dangers can be mitigated with some simple precautions.