Vermiculite was once touted as a miracle mineral: it's fire-resistant and has strong insulation properties. It was incorporated into home insulation products branded Zonolite Attic Insulation in Canada and installed in hundreds of thousands of homes across the country. In fact, in the late 1970s and early 1980s, the federal government even offered a grant to people who installed products including Zonolite in their homes.
But then workers began developing respiratory illnesses at the Montana mine that was the primary source of the world's vermiculite; so did local townspeople. It turned out that some of the ore at the mine was contaminated by asbestos — which can cause serious health problems.
What is vermiculite?
Vermiculite is a volcanic mineral that is fire-resistant and has strong insulation properties. The Environmental Protection Agency notes that when vermiculate is heated, it expands into worm-like or accordion-like pieces and may release asbestos fibres. Vermiculite has been used in various industries including construction, agricultural and horticultural markets for more than 80 years.
What brand of vermiculite contains asbestos?
Vermiculate from the Libby Mine in Montana were used in insulation products sold under the brand name Zonolite Attic Insulation in Canada. Health Canada notes that vermiculate from the Montana mine may contain amphibole asbestos, which when inhaled may cause serious health problems, including cancer.
How is W.R. Grace Co. involved?
W.R. Grace bought the vermiculite mine in Libby in 1963 from the Zonolite Company. More than 680 million kilograms of raw contaminated ore was sent to processing plants across Canada. From one-third to half of the vermiculite from the Libby mine was sold as attic insulation from the 1940s until 1984, when its sale by the company was discontinued.
Was Zonolite widely used?
From 1977 to the mid-1980s, Canadian homeowners who installed products including Zonolite in their home were eligible for grants under the federal government's Canadian Home Insulation Program. Zonolite was estimated to still be in about 300,000 homes across the country in 2008.
The U.S. Environmental Protection Agency estimates that Zonolite was used in as many as 35 million homes and businesses.
Is Zonolite still being sold in Canada?
Insulation made from vermiculite ore from the Libby mine has not been sold in Canada for over a decade, according to Health Canada.
What if I have Zonolite insulation installed in my house?
Stay away from it — if it's left untouched in the attic, there should be minimal or no risk at all, according to Health Canada. The asbestos fibres must be airborne to be inhaled. Each time you breathe asbestos fibres into your lungs, you increase the chance of developing health problems.
The fibres can become trapped in the lungs and can cause lung cancer and mesothelioma, a cancer of the lungs' lining or the abdominal cavity.
According to the U.S. Environmental Protection Agency, there are cases of individuals who got asbestosis — a chronic breathing disorder in which the lungs become scarred with fibrous tissue — from four or five significant contacts with the insulation material. Tradespeople face a higher risk.
What if I'm renovating?
If you suspect you have vermiculate insulation, you should hire an asbestos removal professional before proceeding. Health Canada also suggests sealing cracks and holes in the window frames, door frames and walls. If you suspect Zonolite was installed in your attic, seal up any cracks in the ceilings of the rooms below.
My home insulation looks like vermiculite. How do I know whether it's Zonolite from Libby?
It's impossible to tell just by looking at it. Often, empty Zonolite kraft paper bags were left in the attic. If the bags show that ore was processed by W.R. Grace Canada, Grant Industries or F. Hyde and Co., the product is probably from Libby. If you know you have vermiculite insulation in your attic or walls and you're concerned about it, it probably makes sense to test the material to see whether it contains asbestos.
Can I test the material myself?
If you want to have a sample analyzed, it is suggested that you hire a trained consultant or contractor to collect the sample and get it analyzed at a laboratory. There are numerous consulting companies that perform this kind of asbestos analysis work.
Actes Environmental believes several samples should be taken since asbestos concentration may vary from one vermiculite piece to another.
Also, specialized consultants should be looking for traces of asbestos, even below 0.1 per cent on a weight-to-weight basis. Normally a concentration of less than 0.1 per cent is considered safe. But vermiculite is extremely friable — easily crumbled — and can release a very high number of asbestos fibres in the air when disturbed even if the concentration of asbestos is considered very low.
If there is asbestos in the insulation, should I have it removed?
Before taking that step, homeowners should consider a number of factors. First, removing asbestos-containing materials is typically very expensive. If a significant amount of material is involved, it will probably cost thousands of dollars.
Secondly, due to the physical characteristics of vermiculite, the risk of the material getting into the air is low. If the insulation is not exposed to the home environment — for example, it's sealed behind wallboards and floorboards or is isolated in an attic that is vented outside — the best advice would be to leave it alone.
But if you have a house that needs to be renovated or you use the attic, you expose yourself every time you go up there and risk spreading it to the rest of your house. In those circumstances you are better off removing it, says the U.S. Environmental Protection Agency. To avoid conflict of interest, have the insulation tested by one firm and removed by another. Carefully check the credentials of those you hire. Actes Environmental has the credentials you require.
Sources: Health Canada, U.S. Environmental Protection Agency, Pinchin Environmental, St. Louis Post-Dispatch, Radio-Canada