Photo: Carson Dunlop
More Questions and Answers About Vermiculite Insulation: What is Zonolite? Where was it used? What are the concerns?
What is vermiculite?
Vermiculite is a volcanic material compound that expands when it is heated and has the unusual property of expanding into worm-like or accordion-like pieces. They are usually the size of a nickel or dime. Vermiculite has been used in various industries for more than 80 years. It is used in the construction, agricultural, horticultural and industrial markets.
Where are vermiculite reserves?
Vermiculite is found throughout the world. Countries that hold commercial vermiculite mines include Australia, Brazil, Kenya, South Africa, Zimbabwe and the United States. The vermiculite commercially available today comes from deposits that are not considered harmful.
What brand of vermiculite is dangerous?
More than 70 per cent of the vermiculite ore mined in the world came from the Libby mine, which has been closed since 1990. This particular mine was unusual because the area also included a natural deposit of tremolite asbestos. As a result, much of the vermiculite from the Libby mine was contaminated with tremolite asbestos. According to experts, it's a very toxic form of asbestos, 10 times as carcinogenic as the more prevalent chrysotile asbestos. That vermiculite was sold under the brand name Zonolite Attic Insulation.
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How is W.R. Grace Co. involved in this issue?
W.R. Grace bought the vermiculite mine in Libby in 1963 from the Zonolite Company. More than 1.5 billion pounds of raw contaminated ore was sent to processing plants across Canada. From a third to a half of the vermiculite from this mine was sold as attic insulation from the 1940s until 1984, when its sale by the company was discontinued.
Was Zonolite widely used?
According to documents from the U.S. Environmental Protection Agency (EPA), between 15 and 35 million U.S. homes and businesses were insulated with Zonolite. Documents show about one tenth of the production from Libby was shipped to Canada. It was even on the list of eligible materials for the federal government's Canadian Home Insulation Program (CHIP), a program that offered grants to homeowners from 1977 to the mid-1980s.
What if I have Zonolite insulation?
Stay away from it. If it's left untouched in the attic, there should be minimal or no risk at all. 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. The risk is linked to exposure. It becomes risky is when you have activities that bring you up in the attic, like storing boxes, anything that disturb the material will cause airborne fibres almost immediately.
According to the U.S. EPA, there are cases of individuals who got asbestosis from four or five significant contacts with the insulation material. Tradesman face a higher risk.
What if I'm renovating?
If you are doing work in the attic yourself, such as remodeling, plumbing or rewiring, you should treat Zonolite as asbestos-containing material. You should wear a proper respirator and change your clothes. You have to make sure the fibres won't spread it to other areas of your home. It is recommended to hire a contractor who is properly equipped to work with asbestos.
What should I do if I think I have Zonolite in my attic?
Do not let children play in the area. Do not sweep the Zonolite or use a normal vacuum cleaner. This will re-circulate the dangerous fibres, which could linger in the air for days. There are vacuum cleaners on the market that come with highly sensitive HEPA filters that will capture the fibres.
My home insulation looks like vermiculite. How do I know 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 WR Grace Canada, Grant Industries or F. Hyde and Co, the product is probably from Libby and is likely contaminated. 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 if 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.
According to Bruce Stewart from Pinchin Environmental in Mississauga, there should be several samples 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 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 costs thousands of dollars.
Secondly, due to the physical characteristics of vermiculite, there's a low potential the material is getting into the air. If the insulation is not exposed to the home environment (for example, it's sealed behind wallboards and floorboards or is isolated in the attic which 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. EPA. To avoid conflict of interest, have the insulation tested by one firm and removed by another. Carefully check the credentials of those you hire.
What do Canadian health authorities have to say?
The Government of Canada recognizes that breathing in asbestos fibres can cause cancer and other diseases. We help protect Canadians from asbestos exposure by regulating:
Gil Strachan is a professional home inspector, representing Electrospec Home Inspection Services in east-central Ontario since 1994.