Danger seen in popular home insulation product

Apr 19, 2003 | 2003 Toronto Star Columns

By Bob Aaron
Toronto Star contributing columnist

Bob Aaron

Bob Aaron bob@aaron.ca

April 19 2003

Danger seen in popular home insulation product

Some vermiculite product tainted by toxic asbestos

Production stopped in 1984 at Montana mine


Every homeowner has reason to be concerned about potentially dangerous substances which might be found in Canadian homes – urea formaldehyde, radon gas, asbestos, mould, and other harmful gases, bacteria and dust.

Now it may be time to add another one to the list. In its latest environmental law bulletin, the Toronto environmental law firm of Willms & Shier claims that potentially dangerous vermiculite attic insulation may be found in some Canadian homes.

Carcinogenic asbestos fibres in the vermiculite may be contaminating hundreds of thousands of Canadian homes, according to the Willms & Shier newsletter.

It seems that vermiculite attic insulation sold under the trade name Zonolite from 1940 to 1984 is contaminated with tremolite, an extremely carcinogenic form of asbestos may be found in some Canadian homes.

By itself, vermiculite is harmless. In fact, it used to be called "the miracle mineral." After it was heated, it was useful for potting soil, home insulation and fireproofing. It was a very popular product in Canada and the United States for three decades, from the 1950s through the late 1970s. In fact, under its Canadian Home Insulation Program (CHIP), the Canadian government subsidized homeowners who upgraded their insulation with vermiculite from 1977 to the mid-1980s.

A primary source of the material was a mine in Libby, Montana, operated by W.R. Grace Co. starting in 1963.

A documentary on The National on CBC News in February cited expert reports alleging that the tremolite asbestos is found in the Libby mine. Tremolite is a toxic form of asbestos, 10 times as carcinogenic as the more prevalent chrysotile asbestos. The documentary stated that more than 70 per cent of world supplies of the compound came from Libby before the mine was closed.

More than 1.5 billion pounds of raw contaminated ore was shipped from Libby to Canadian processing plants before 1984 when its sale by the company was discontinued.

Recently, I spoke to Bruce Stewart, senior vice president of Pinchin Environmental Ltd., one of Canada s largest environmental health and safety consulting firms. He told me that 95 per cent of Canadian supplies of vermiculite came from the mine in Montana. It was shipped to six Canadian provinces, and processed in places like Montreal, St. Thomas, Ajax, Toronto, and five plants in Western Canada.

Stewart s estimate was that as many as 30 million American homes contain the toxic form of vermiculite. It s anyone s guess how many hundreds of thousands of Canadian homes are contaminated.

The best advice for the owners of those homes is to avoid any contact with vermiculite insulation contaminated with tremolite. It only becomes dangerous when it is disturbed, and airborne asbestos fibres are breathed into the lungs. According to the U.S. Environmental Protection Agency, as few as four or five contacts with the contaminated vermiculite can cause asbestosis.

Any disturbance of the attic material can be dangerous. Remodelling, plumbing, wiring, renovation or storing goods in the attic can lead to serious health risks.

Removal of contaminated vermiculite insulation can be very expensive because of the need to protect the workers from toxic dust particles, and the risk of spreading the material throughout the rest of the house.

Only expert testing can determine whether vermiculite insulation material is from the Libby mine, and the typical homeowner will have no idea whether the attic contains the toxic substance. As a result, a warranty in an agreement of purchase and sale that there is no vermiculite insulation in a house will probably be meaningless.

W.R. Grace says on its Web site that there is no unreasonable risk of injury or illness associated with the presence of this insulation in their homes and that homeowners should leave it in place (

Following a torrent of lawsuits filed against it, W.R. Grace filed for bankruptcy protection in 2002.

The Canadian government through its Health Canada Web site remains silent on the health dangers of the contaminated vermiculite, and the government s role in subsidizing the use of the product under the CHIP program.

It s time for the Canadian government to take ownership of the problem, and reassure us that it is not ignoring a potentially serious health risk to millions of Canadians.


Bob Aaron is a Toronto real estate lawyer. Send questions to Bob Aaron, 10 King Street East, #1400, Toronto, Ontario M5C 1C3, or by e-mail to bob@ aaron.ca , phone 416-364-9366, or fax 416-364-3818.


Bob Aaron is a Toronto real estate lawyer. He can be reached by email at bob@aaron.ca, phone 416-364-9366 or fax 416-364-3818.
Visit the Toronto Star column archives at https://www.aaron.ca/columns for articles on this and other topics or his main webpage at www.aaron.ca.


Contact Bob Aaron

Bob Aaron is a Toronto real estate lawyer and frequent speaker to groups of home buyers and real estate agents.
He can be reached by email at bob@aaron.ca, phone 416-364-9366 or fax 416-364-3818.

Aaron & Aaron specialize in Real Estate Law, specifically Sale of Rental, Condominium, Residential, Rural Recreation, Offer to Lease, Commercial, and New Construction

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