Vermiculite insulation was sold in Canada under the name of Zonolite® and was extracted from the Libby Mine in Montana, USA. This mine had a natural deposit of asbestos which resulted in the vermiculite being contaminated with asbestos.
What is vermiculite?
Vermiculite is a naturally occurring mica-like mineral that has the unusual property of expanding into worm-like accordion shaped pieces when heated.
The treated vermiculite becomes a light-weight, fire-resistant, absorbent, and odourless material. These properties allow vermiculite to be used to make numerous products, including attic insulation. Vermiculite insulation is a pebble like poured in material and is usually light brown to gold in colour. Sizes of vermiculite products range from very fine particles to large (course) pieces nearly an inch long. It is also common to find vermiculite as loose fill insulation in outside wall cavities including concrete block walls.”
Vermiculite is also used in acoustic finishes, concrete mixes for swimming pools, agricultural and horticultural products, and in industrial products (i.e. brake shoes and pads, drilling mud, furnaces, and insulation blocks).
Why is vermiculite insulation a problem?
Vermiculite insulation has been an established commercial commodity for well over 50 years, and is currently used throughout the world. Of concern is the vermiculite ore produced by the Libby Mine in Montana from the 1920’s to 1990. During this period, the Libby Mine accounted for more than half the worldwide production of vermiculite. One tenth of the Libby Mine production was shipped to Canada.
Unfortunately, the vermiculite produced at the Libby Mine was found to be contaminated with asbestos and asbestos like fibers. Workplace exposure to these fibers caused a serious health problem with local miners and millers, as well as some downstream workers.
The Libby Mine produced vermiculite was sold in Canada under the name Zonolite Attic Insulation and possibly other brands. The type of asbestos contamination present is tremolite, a particularly hazardous form of asbestos and the concentration ranges from 0.3% to 7%.
I have vermiculite insulation in my building – does it contain asbestos?
Products made from vermiculite ore produced by the Libby Mine were not widely used after the mid-1980’s and have not been on the market in Canada for more than 10 years. Not all vermiculite produced before 1990 contains asbestos fibers. However to be safe and in the absence of evidence to the contrary, if your building has older vermiculite insulation, it is reasonable to assume it contains asbestos.
If you wish to test your vermiculite insulation for the presence of asbestos, have a professional collect three samples for laboratory analysis. The samples should be collected and analyzed following USEPA method EPA / 600 / R-04 / 004 (Sampling and Analysis of Fibrous Amphibole in Vermiculite Attic Insulation).
Today, vermiculite is mined at facilities which are asbestos free or have low levels of asbestos contamination in the finished material.
What should I do if I have vermiculite attic insulation?
DO NOT DISTURB IT. Any disturbance has the potential to release asbestos fibers into the air. Vermiculite insulation that is contained and not disturbed poses very little risk to building occupants. If you decide to remove vermiculite insulation from your building, speak to a trained and qualified asbestos removal professional. NEVER attempt to remove the insulation yourself.
Further information on minimizing your exposure to asbestos in vermiculite can be found on the Health Canada and USEPA websites. Alternatively, you can contact your local Power Environmental representative.
How can Power Environmental help me?
Power Environmental is a leading provider of environmental services involving hazardous materials and indoor air quality. These services include investigations, remediation and contracting. We have pioneered the development of low cost removal vermiculite techniques involving the use of industrial power vacuums and high efficiency cloth filter bags. All work is done in accordance with Ministry of Labour Regulations using certified crews specially trained for this type of work.