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Controlling the Hazard and Liability of Asbestos in Vermiculite Insulation
Warnings for the Homeowner, Building Manager, Contractor and Real Estate Industry

Originally Published by Pinchin Environmental

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.

Testing for Asbestos in Vermiculite
Vermiculite insulation in loose form can be readily visually identified as a light weight, silvery grey or blonde, granular, layered material, with particle sizes of about 2 to 10 millimeters. If vermiculite is known to have been installed prior to 1990, visual identification should be adequate to confirm the material as asbestos-suspect.

The visual identification can be confirmed by laboratory testing, although caution in selecting the laboratory is advised. The laboratory should be accredited by one of the two US agencies that qualify laboratories for the analysis of asbestos in bulk samples. Even these laboratories require extra care to detect the very fine fibres at these low concentrations. Laboratories that do not specialize in asbestos analysis should never be relied on for asbestos analysis.

If the owner decides to test the vermiculite for asbestos content, the US EPA advises using a respirator effective against asbestos during sample collection. The sample should be taken from the bottom and lower section of insulation since the finer particles or dust (which contains a higher concentration of asbestos) tend to settle out of the vermiculite particles. Sampling only the top of the insulation may provide a false negative analysis for asbestos.

It is extremely important to note that the overall percentages of asbestos in the bulk vermiculite are very low, possibly below existing legal limits for asbestos. None-the-less, the airborne concentrations can be very high when the material is disturbed, due to the very fine and loose nature of the asbestos. A recent US EPA study of six homes in Vermont showed elevated airborne asbestos concentrations even in cases where the laboratory could not detect asbestos in the bulk material. Therefore EPA recommends that all loose-fill insulation visually identified as vermiculite, and installed prior to 1990, be treated with asbestos precautions

Risk to Occupants and Contractors
The Pinchin Group is aware of many studies that confirm the potential for harmful asbestos exposures when vermiculite insulation is disturbed. The US EPA study referred to earlier indicated that, in homes with vermiculite insulation, asbestos was not detected in the air or dust samples in the home in the absence of disturbance of the insulation. However even relatively minor disturbances generated excessive levels of airborne asbestos in the area of disturbance.

It is not possible, partly because of the variable amounts of the asbestos in the vermiculite, to predict with certainty the actual airborne concentration. The current occupational exposure limit for asbestos is 0.1 fibers per cubic centimeter of air (f/cc). Compared to this, levels of airborne asbestos measured in various studies using either optical or electron microscopes confirmed very elevated exposure levels.

These results strongly support the following recommendations for homes from the US EPA publication "Current Best Practice for Vermiculite Attic Insulation".

This same advice should be followed if vermiculite insulation is found in other settings.

• Vermiculite insulation should be left undisturbed. Due to the uncertainties with existing testing techniques, it is best to assume that the material may contain asbestos.
• Do not store boxes or other items in the attic if retrieving the material could disturb the insulation.
• Children should not be allowed to play in attics with open areas of vermiculite insulation.
• If renovations are planned that might disturb the vermiculite, it should be first removed by professionals trained and certified to handle asbestos.
• The homeowner or maintenance personnel should never attempt to remove the insulation. Hire professionals trained and certified to safely remove the material.