Controlling the Hazard and Liability of Asbestos in
Vermiculite Insulation

Warnings for the Homeowner, Building Manager, Contractor and Real Estate Industry

Vermiculite insulation was installed as ceiling and wall insulation in hundreds of thousands of Canadian homes, offices, banks and other buildings. Much of this material is contaminated with potentially dangerous asbestos fibres.

Homeowners and property managers need to put careful controls in place to prevent disturbance of the insulation. Careful removal should precede any significant disturbance, for example, prior to renovations.Those involved in property assessments and transfers (building inspectors, real estate agents and brokers, lawyers, mortgagors) should warn the prospective purchaser of the presence of vermiculite insulation and consider its impact on property value.

Sources of Vermiculite Insulation

Vermiculite, a mineral mined around the world, is used in a variety of commercial and consumer products. After crushing and processing, the raw ore was shipped to many plants in Canada for exfoliation or expanding.

At these plants, the ore was heated to about 1000°C causing it to expand like popcorn into a lightweight granular material that is fire-resistant, absorbent, light weight and a good insulator.Vermiculite has been and continues to be used in a variety of building materials.

It was made into a variety of insulation products, was used as a loose fill insulation inside masonry block walls (the largest volume use), stove pipe and stack insulation, fire separations, cold rooms and in walls and attics of buildings, mostly homes. It is important to understand not all vermiculites contain asbestos.

Asbestos Contamination

Some vermiculite mines contain varying amounts of asbestos minerals mixed in the vermiculite deposit. Of particular importance to Canada was the Libby Montana mine owned by W.R. Grace, reported by the U.S. Environmental Protection Agency as the source of as much as 70% of the world's consumption until it closed in 1990.

The Libby deposit was contaminated with an asbestos mineral usually identified as tremolite. Although W.R. Grace took increasing measures through the history of the operation to reduce the asbestos content in their products, it is likely that most of their production contained at least a trace of free asbestos fiber.

Once vermiculite was mixed with a binder (as in concrete and plaster mixes, sprayed, fireproofing, etc.) it is unlikely to ever release significant airborne asbestos. The loose fill products do, however, pose a risk, causing substantial asbestos exposure when disturbed.

Exposure to asbestos for prolonged periods or at high concentrations increases the risk of lung cancer and other respiratory diseases. Many of the Libby workers and residents have become sick or died of asbestos disease originating from the mining and milling operations or from the handling and installation of vermiculite insulations. Workers involved in the vermiculite expansion plants have also been afflicted with asbestos disease. In Canada, construction workers are now protected from the hazards of asbestos exposure by detailed health and safety regulations.

Vermiculite in Canadian Buildings

The WR Grace asbestos-contaminated insulation was installed in many Canadian buildings, particularly in homes, but also in commercial, institutional and industrial buildings. There is no solid estimate of the number of affected Canadian buildings but it is almost certainly several hundred thousand or more, based on US EPA estimates. Its use in Canadian residential construction was certainly increased by inclusion in the CHIP Program between 1977 and 1984. This was the same program under which most Urea Formaldehyde Foam Insulation (UFFI) was installed, although to date the Federal Government has not addressed the cost to remove vermiculite insulation in the same way as the UFFI removal was funded.

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