Asbestos, Asbestosis, Mesothelioma

A new advisory from Health Canada warns homeowners to stay away from vermiculite insulation that may contain asbestos.

The insulation, which was used in Canada until the mid-1980s, and sold primarily under er the brand name of Zonolite, may contain asbestos. When fibres from asbestos are in the air people breath, they can cause lung cancer or other serious respiratory illnesses. While not all vermiculite insulation contains asbestos, it's best to assume the worst and take precautions if you have it in your home.

Health Canada says that if the insulation is sealed behind wallboards and floorboards, isolated in an attic, or otherwise sealed from the living areas of the home, there is "currently no evidence of risk to your health." However, when the insulation is moved during maintenance, renovation or demolition work, fibres can be released into the air and become a hazard.

Photos of vermiculite insulation are available at the Health Canada link above, and at the U.S. Environmental Protection Agency's website.

If you know you have vermiculite-based insulation in your attic, Health Canada says don't allow children to play there, and don't use the area for storage because moving things around could disturb the insulation. If you must go into the attic, walk on boards and use a respirator mask. Regular dust masks will not protect against asbestos fibres. Seal all cracks and holes in the ceilings of the rooms below the insulation, including light fixtures and the attic hatch, to prevent insulation from sifting through.

If you suspect there is vermiculite-based insulation in the walls, seal all cracks and holes. Aply caulking around window and door frames, along baseboards and around electrical outlets.

Most importantly, if you must renovate or repair the area, hire a contractor who is trained to deal with asbestos removal. They are listed in the Yellow Pages under Asbestos. Asbestos is a natural mineral that can resist high temperatures, and is a good insulator. It has been used for hundreds of applications -- the ancient Greeks wove it into oil lamp wicks, funeral shrouds and ceremonial tablecloths, says Canada Mortgage and Housing Corp.

It's still used in some industries, and in some household products such as roofing, flooring and appliances. The products are regulated under the Hazardous Products Act, and are encapsulated and sealed to reduce the escape of fibres.

The vermiculite ore, used to make the insulation that may contain asbestos, came from the Libby Mine in Montana, which was in operation from 1920 to 1990. It has been more than 10 years since the insulation was sold in Canada, and Health Canada says it wasn't widely used here after the mid-1980s.

"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," says Health Canada.

"Asbestos related illnesses are usually associated with frequent and prolonged exposure to asbestos," says the federal agency. "The time it takes to develop a disease from exposure to asbestos is usually long -- up to decades."

How the exposure can affect you depends on the concentration of asbestos fibres in the air, how long the exposure lasted, how often you were exposed, the size of the fibres inhaled and the amount of time since the initial exposure.

"When inhaled in significant quantities, asbestos fibres can cause asbestosis (a scarring of the lungs which makes breathing difficult), mesothelioma (a rare cancer of the lining of the chest or abdominal cavity) and lung cancer," says Health Canada. "The link between exposure to asbestos and other types of cancers is less clear.

"Based on current information, there is no evidence that vermiculite currently available for horticultural purposes (such as potting plants) is a health risk when used as directed." Health Canada says if you are concerned about exposure to the material, talk to your doctor. Minimize further exposure to asbestos by following the guidelines above.

Smoking and exposure to second-hand tobacco smoke and other irritants also increases your chances of developing lung cancer.

For more information, Canadians are encouraged to visit the website above or call Health Canada at 1-800-443-0395.

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