The following info is from Health Canada's official site:

The Issue

Some vermiculite insulation may contain amphibole asbestos fibres. These products can cause health risks if disturbed during maintenance, renovation or demolition. However, there is currently no evidence of risk to your health if the insulation is sealed behind wallboards and floorboards, isolated in an attic, or otherwise kept from exposure to the interior environment.

Background

Photo courtesy of CMHC

Vermiculite is a mica-like mineral mined around the world and used in a variety of commercial and consumer products because it is fire-resistant and has good insulation qualities. Of concern is vermiculite ore produced by the Libby Mine in Montana from the 1920's to 1990. It was sold as Zonolite^® Attic Insulation and possibly other brands in Canada during that time. Vermiculite from the Libby Mine may contain amphibole asbestos. The Libby Mine supplied the majority of the world market in vermiculite-based insulation.

Photo courtesy of EPA

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 since 1990. Not all vermiculite produced before 1990 contains amphibole 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 amphibole asbestos.

The Health Risks Of Vermiculite Containing Amphibole Asbestos

Although the overall percentages of amphibole 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. How exposure to asbestos 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 asbestos 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. 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 (e.g. potting plants) is a health risk when used as directed.

Minimizing Your Risk

The best way to minimize your risk of amphibole 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.

If you are concerned that your home may contain vermiculite-based insulation visit the Need More Info? section in this article or the Health Canada Web site to get the most up-to-date information as it becomes available.

If you know you have vermiculite-based insulation in your attic, take these precautionary steps.

• 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 amphibole 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. For information on appropriate respirator masks, see the Need More Info? section.
• 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--for instance, by re-insulating your attic--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 door frames, along baseboards and around electrical outlets.

What To Do If You Suspect You Have Been Exposed To Asbestos

Asbestos related illnesses are usually associated with frequent and prolonged exposure to asbestos. The time it takes to develop a disease from exposure to asbestos is usually long - up to decades. However, some steps you can take if you have concerns about exposure to asbestos are:

• Talk to your health care provider;
• Avoid or minimize further exposure to any form of asbestos; and
• Stop smoking and avoid second hand tobacco smoke and other irritants that could affect your lungs. Exposure to cigarette smoke and asbestos greatly increases your chances of developing lung cancer.

Need More Info?

For the most up-to-date information on this issue, call 1-800-443-0395

For more information on asbestos, visit the following sites:

• It's Your Health article Health Risks of Asbestos
• The Canada Mortgage and Housing Corporation publication on  Asbestos

For information on general safety tips and guidelines for working with different types of insulation and other materials, visit:

• Natural Resources Canada publication, Keeping the Heat In, Chapter II, Part IV,
   Health and Safety Considerations

For specific information on safety precautions and acceptable respirator masks when working with asbestos, go to:

• Canadian Centre for Occupational Health and Safety (CCOHS)  Respirator page
  Tel: 1-800-668-4284 (toll-free in Canada and USA)

For more information on workplace safety, visit the Environment and Workplace Health, Occupational Health and Safety Web section

For more information on vermiculite and asbestos visit, the following Web sites:

• Natural Resources Canada publication on  Chrysotile Asbestos
• Health Canada, Consumer Product Safety Web section
• Health Canada, Environmental Contaminants Web section
•  Agency for Toxic Substances and Disease Registry (ATSDR)

For more information on the  Hazardous Products Act (HPA) and asbestos, see Justice Canada's Web site

For more photographs of vermiculite insulation and additional information regarding vermiculite containing asbestos, please visit the US EPA's  Asbestos Home Page

For additional articles on health and safety issues go to the It's Your Health Web section
You can also call toll free at 1-866-225-0709 or TTY at 1-800-267-1245

Updated: September 2009
Original : March 2004
©Her Majesty the Queen in Right of Canada, represented by the Minister of Health, 2009

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ASBESTOS info from the CMHC site:

Asbestos is a natural mineral with unusual qualities. It is strong enough to resist high temperatures, chemical attack and wear. A poor conductor, it insulates well against heat and electricity.

Asbestos crystals become long, flexible, silky fibres, so it can be made into a wide variety of forms. It can be spun into yarn, woven into cloth or braided into rope. Asbestos can also be added to materials as diverse as cotton and cement.

This combination of properties gives asbestos performance capabilities that are difficult to match.

What has asbestos been used for?

Asbestos has been used in hundreds of applications and products over the past 4,500 years. The ancient Greeks wove it into oil lamp wicks, funeral shrouds and ceremonial tablecloths. During the 1800s, it insulated the hot engines, boilers and piping that powered the Industrial Revolution.

For half a century, until the 1980s, asbestos was used in office buildings, public buildings and schools. It insulated hot water heating systems, and was put into walls and ceilings as insulation against fire and sound.

Asbestos has also been widely used in transportation and electrical appliances, frequently mixed with, and encased in, other materials.

Asbestos has also been found in many products around the house. It has been used in clapboard; shingles and felt for roofing; exterior siding; pipe and boiler covering; compounds and cement, such as caulk, putty, roof patching, furnace cement and driveway coating; wallboard; textured and latex paints; acoustical ceiling tiles and plaster; vinyl floor tiles; appliance wiring; hair dryers; irons and ironing board pads; flame-resistant aprons and electric blankets; and clay pottery. Loose-fill vermiculite insulation may contain traces of “amphibole” asbestos.

How has the use of asbestos changed?

When it became evident that regular exposure to asbestos on the job involved health risks, the public became more concerned about exposure to asbestos in offices and schools, and, eventually, about all asbestos products.

This concern has led to a dramatic decline in asbestos use since the early 1980s. The use of asbestos insulation in buildings and heating systems has virtually disappeared. Residential use, for roofing, flooring and appliances, continues to decrease.

While alternative products are being developed to replace asbestos, products sold today containing asbestos are regulated under the Hazardous Products Act. Asbestos can be used safely, and public concern has led to improved product design and manufacture. Asbestos is now better encapsulated and sealed to reduce the escape of fibres.

Asbestos is valuable in many applications because it has been difficult to find comparable substitute materials. For example, it is still an important component of brake lining and clutch facings.

What health problems are associated with exposure to asbestos?

Health Canada states that the asbestos content of a product does not indicate its health risk.

Asbestos poses health risks only when fibres are in the air that people breathe. Asbestos fibres lodge in the lungs, causing scarring that can ultimately lead to severely impaired lung function (asbestosis) and cancers of the lungs or lung cavity.

Concern for the health of asbestos workers was expressed as long ago as the late 1800s. The risks became more evident in the late 1960s, when workers who had been heavily exposed 20 to 30 years earlier showed increased incidence of lung disease. Occupational exposure is now strictly regulated by provincial governments.

When can asbestos be a problem in the home?

Today, far fewer products in the home contain asbestos. Current products that do contain the material are better made to withstand wear and use.

However, frequent or prolonged exposure to asbestos fibres may still bring health risks. This can happen with the release of fibres into the air when asbestos-containing products break down, either through deterioration as they age or when they are cut. People can put themselves at risk — often without realizing it — if they do not take proper precautions when repairs or renovations disturb asbestoscontaining materials. This can occur in a number of situations:

• Disturbing loose-fill vermiculite insulation which may contain asbestos
• Removing deteriorating roofing shingles and siding containing asbestos, or tampering with roofing felt that contains asbestos
• Ripping away old asbestos insulation from around a hot water tank
• Sanding or scraping vinyl asbestos floor tiles
• Breaking apart acoustical ceilings tiles containing asbestos
• Sanding plaster containing asbestos, or sanding or disturbing acoustical plaster that gives ceilings and walls a soft, textured look
• Sanding or scraping older water-based asbestos coatings such as roofing compounds, spackling, sealants, paint, putty, caulking or drywall
• Sawing, drilling or smoothing rough edges of new or old asbestos materials

How to minimize the asbestos risks in the home?

If you do not know if products in your home contain asbestos, have an experienced contractor inspect them. If there is asbestos, the best interim measure (unless the product is peeling or deteriorating) is to seal the surface temporarily so that fibres will not be released into indoor air. If the product is already protected or isolated, simply leave it alone.

It is a complex and expensive matter to remove asbestos, and should be done by an experienced contractor. When disturbing an asbestos product, maximum precautions must be taken to safeguard the workers and anybody else who may be nearby. Asbestos dust must remain within the work area so that it cannot be breathed in by unprotected persons.

It is essential to take adequate precautions. Everybody who works with asbestos should always wear an approved face mask and gloves, along with protective clothing. Be sure to tape sleeve and trouser cuffs, and wash clothes separately after use. Keep the work area moist to keep dust and fibre particles from floating into the air. Isolate the work space.

Reduce the air pressure to prevent asbestos fibres from escaping from the work area, and filter the exhaust air. Dispose of all waste appropriately, according to the guidelines of your provincial department of the environment. Other removal methods may be warranted for special conditions — consult an expert.

Vermiculite Insulation

Some vermiculite may contain asbestos.

• Do not disturb loose-fill vermiculite insulation.
• Do not store items near vermiculite insulation, if the insulation can be disturbed.
• Do not allow children near loose fill vermiculite insulation.
• If activities are planned that will disturb vermiculite, consult a certified asbestos removal company.

Where can you get more information on asbestos?

For information on how to minimize exposure to asbestos refer to:

It's Your Health — Vermiculite Insulation Containing Asbestos
Health Canada

For information on occupational exposure to asbestos, contact the:

Canadian Centre for Occupational Health and Safety (CCOHS)
135 Hunter Street East
Hamilton, ON
L8N 1M5
Phone: 1-905-570-8094
Toll-Free: 1-800-668-4284
Fax: 1-905-572-2206
Web Site: www.ccohs.ca

For contractors who specialize in asbestos abatement and removal, look in the Yellow Pages™ under "Asbestos".

US EPA's Asbestos Home Page

Although this information product reflects housing experts' current knowledge, it is provided for general information purposes only. Any reliance or action taken based on the information, materials and techniques described are the responsibility of the user. Readers are advised to consult appropriate professional resources to determine what is safe and suitable in their particular case. CMHC assumes no responsibility for any consequence arising from use of the information, materials and techniques described.