Vermiculite  Insulation



Feds Warn That Vermiculite Insulation Poses Danger From Asbestos
In a recent memo to the National Institute of Occupational Safety and Health, assistant U.S. surgeon general, Dr. Hugh Sloan of the U.S. Public Health Service, has warned that Asbestos-contaminated vermiculite insulation in millions of homes across the country poses a "substantial health risk'' to anyone who works in the houses' attics.  "Internal company documentation and recent testing of residential insulation material reveals that even minimal handling by workers or residents poses a substantial health risk,'' says Sloan.   He goes on to say that while recent studies show that even casual handling of the insulation can expose workers or homeowners to 150 times the asbestos level considered safe under federal regulations, the risk to homeowners would be small if they leave the insulation alone.  "My sense is that homeowners themselves, if the insulation remains undisturbed, shouldn't have any worry,"

According to Aubrey K. Miller, an official in the health service's Denver region, The Public Health Service has asked the National Institute of Occupational Safety and Health to "look into the current worker exposures that may be dealing with these products and issue an alert if need be."



What Is Vermiculite Insulation?
It is an insulation product that contains a mineral called vermiculite that comes from mines in Libby, Montana and other mines across the United States and other countries.  For more than 60 years, W.R. Grace & Co. dug vermiculite ore out of the Zonolite Mountain in Libby. Vermiculite is a volcanic mineral compound that expands when wet. It is used in agricultural, construction, horticultural and industrial applications, including pesticides, insulation, potting mixes, brake pads, sound deadening materials, fire protection, paints, sealants, insulating concrete and nuclear waste disposal.

Insulation made of vermiculite was sold under the brand name Zonolite, and was sold as a product for attic insulation and marketed until the mid 1980's.  Vermiculite from Grace's mine at Libby, Mont., was sold for use in garden products, fireproofing, cement mixtures and more than a dozen other consumer products. The bulk of the ore was heated until it expanded like popcorn.  Then marketed as Zonolite insulation, it was stuffed between rafters and inside walls in millions of homes from coast to coast.  Nobody is sure how many homes contain Zonolite. Estimates range between 2.5 million and 16 million. 

"It sold like mad,'' said Stephen Sheeran, who was a salesman for Grace in Michigan and eventually a sales manager for the company. "Millions of bags of that stuff from Libby were sold as attic fill insulation,'' Sheeran said. "They couldn't get it fast enough."  Vermiculite (Zonolite) products were widely marketed by various suppliers. Records indicate that an estimated 80 % of the worlds' supply of vermiculite came from Libby, Montana. Records further indicated that approximately 300,000 pounds of asbestos per day went through the primary ore-processing facility.



What Does Vermiculite Insulation Look Like?
Vermiculite insulation is easily distinguished from the much more common types of loose fill insulations - cellulose, fiberglass and rock wool. All of these common insulation types are fibrous. In contrast vermiculite is in the form of brownish-pink or brownish-silver accordion-shaped chips.


vermiculite_1.jpg (222315 bytes)

Click on the thumbnail image to view a photo of vermiculite

 insulation in a typical residential attic.



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Click on the thumbnail image to view a photo of a

microscopic view of vermiculite.



Should I Have It Removed From My Home?
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, 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 might be to leave it alone.

If you suspect you have vermiculite in your home, the U.S. Environmental Protection Agency (EPA) recommends you do not disturb it.  You should consider contacting an asbestos specialist for further advice.



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