Vermiculite in the house?!
Vermiculite was used in insulation products in many Canadian and American houses. A good part of that vermiculite, sold in North America, was extracted from a mine where the ore naturally contained a small percentage of asbestos tremolite, an amphibole.
If removed, these insulation products can be dangerous for health.
The ore causing trouble is the one extracted from the mine Libby (Montana), between 1920 and 1990. It was sold in Canada between 1963 and 1984 under the brand Zonolite® Attic Insulation. Santé Canada estimated that approximately 200 000 houses in Canada contain this insulator. Please note that this vermiculite contained, naturally, a small percentage of tremolite.
What to do with this insulation product?
If the tremolite fibres are integrated or sealed in the insulation product (the fibres should not be released in the air), it is not risky for health. The best way of reducing the exposure to tremolite is to avoid removing the insulation product. If the product is contained, therefore absent from ambient air of the house, the risk is tiny.
Tremolite and chrysotile
The tremolite fibres have a very large biopersistance in the lungs, contrary to chrysotile’s. One thus should not confuse all the kinds of asbestos; this vermiculite case in is a good example. Today, the only asbestos fibre commercialized is chrysotile.
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