Vermiculite Insulation Warning


Vermiculite Insulation Containing Asbestos

Alberta Municipal Affairs, Safety Services Branch is aware of a Health Canada advisory concerning vermiculite insulation mined at the Libby Mine in Montana. The vermiculite was sold as Zonolite® Attic Insulation and possibly other brands in Alberta from the 1920’s to 1990. The Health Canada advisory warns vermiculite insulation from the Libby Mine may contain asbestos.

What is vermiculite?

Vermiculite is a mica-like mineral mined around the world and used in a variety of commercial and consumer products, including as attic insulation in homes, because it is fire-resistant and has good insulation qualities. Vermiculite from the Libby Mine may contain asbestos. The Libby Mine supplied the majority of the world market in vermiculite-based insulation.

Products made from vermiculite ore produced by the Libby Mine were not widely used after the mid-1980's and have not been on the market in Canada for more than 10 years. 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.

Photo courtesy U.S. Environmental Protection Agency

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. If asbestos fibres are enclosed or tightly bound in a product, for example in asbestos siding or asbestos floor tiles, there are no significant health risks.

Photo courtesy Canada Mortgage and Housing Corporation

Safety tips

The best way to minimize your risk of asbestos exposure is to avoid disturbing vermiculite-based insulation in any way. If vermiculite-based insulation is contained and not exposed to the home or interior environment, it poses very little risk.

Health Canada advises taking the following precautionary steps if you know you have vermiculite-based insulation in your attic:

  • Do not allow children to play in an attic with open areas of vermiculite-based insulation and make sure anyone working in the attic knows about the possible presence of asbestos.
  • Do not use the attic for storage if retrieving items from it may disturb the insulation.
  • If you must go into the attic, walk on boards in order to minimize disturbance of the insulation and use an appropriate respirator mask. Do not remain in the attic any longer than is necessary.
  • Common dust masks are not effective against asbestos fibres. Visit the Health Canada web site referenced below for information on appropriate respirator masks.
  • If you have vermiculite-based insulation and you decide to have it removed, speak to trained and qualified asbestos removal professionals to handle the insulation removal. They can be found by looking up experts in "asbestos abatement /removal." NEVER attempt to remove the insulation yourself.
  • If you plan to remodel or renovate in a manner that would disturb the vermiculite, speak to professionals who are trained and qualified to handle asbestos removal before proceeding with the work to be done.
  • Seal all cracks and holes in the ceilings of the rooms below the insulation (for example, apply caulking around light fixtures and the attic hatch) to prevent insulation sifting through.
  • If you suspect you have vermiculite-based insulation in your walls, as a precautionary step, seal all cracks and holes. For example, apply caulking around window and doorframes, along baseboards and around electrical outlets.

The foregoing is reproduced from information prepared by Health Canada.

Further Information:

Health Canada
Telephone:     1-800-443-0395

Alberta Employment and Immigration - Workplace Health & Safety
Telephone:     1-866-415-8690

Alberta Municipal Affairs - Safety Services Branch
Telephone:     1-866-421-6929