Zonolite

Zonolite Insulation

Zonolite, the brand name of attic insulation formerly manufactured by the W. R. Grace Company, contains asbestos. Significant exposure to asbestos increases the risk of lung cancer, malignant mesothelioma and other lung disorders. As a result, government agencies (e.g. OSHA and the Environmental Protection Agency) set limits on exposure to asbestos in the workplace and actively pursue not only methods for reducing the exposure to asbestos but also for cleaning up sites of former manufacturing operations with heavy asbestos usage (e.g. SuperFund sites).

Asbestos

Asbestos is a group of minerals exhibiting characteristic long, thin fibers that separate from each other. Working with or disturbing asbestos-containing materials potentially releases fibers into the surrounding air, where they can be inhaled and lodge in the lungs. While the lungs are capable of clearing themselves of a variety of pollutants, the long fibers of asbestos cannot be cleared as readily, setting the stage for lung malfunction and disease.

Asbestos occurs naturally in the environment but poses little threat to the average citizen in its natural form. However, throughout the 20th Century, asbestos-containing minerals were widely used in construction and manufactured products. Evidence of significantly increased rates of lung disease in miners and other workers exposed to asbestos brought the potential risks of asbestos to the forefront.

The Role of Vermiculite

While asbestos was purposely included in building products, for example in asbestos floor tile, asbestos was not intentionally included in the formulation of Zonolite attic insulation. Rather Zonolite was manufactured from vermiculite, another naturally occurring mineral, which was mined in Libby, Montana. Vermiculite mines are found around the world but the Zonolite product utilized only vermiculite from the Libby mine which, along with the insulation manufacturing facility, was owned by the W. R. Grace Company.

The mineral vermiculite has valuable chemical properties. Somewhat like popcorn, when heated vermiculite expands to fluffy light granules which are fire resistant, chemically inert and lightweight, making vermiculite an excellent insulating material. Vermiculite’s light weight was especially useful in attic insulation applications.

The asbestos problems of Zonolite arose because the geological content in the area of the Libby mine included tremolite asbestos which was mined along with the vermiculite. Residual asbestos in the vermiculite of course was included in the Zonolite insulation that was sold as attic insulation for millions of homes across the Unites States from 1963 through 1984.

The Libby mine ceased operations in 1990 due to the effects of asbestos exposure on mine workers and residents. According to government estimates, approximately 1,800 residents of the town of Libby, Montana died or become ill from the asbestos dust generated at the mine during its operations. An estimated 20 new cases of asbestos-related illnesses occur each month due to the long-term residual effects of the asbestos dust. To put these numbers into perspective, the town of Libby and a 10-mile radius around it have a population of 15,000. The Libby mine and the surrounding area have been declared an EPA Superfund site.

Zonolite Insulation

The danger posed by Zonolite insulation to home dwellers was debated but it is now accepted that anyone who lives in a house with Zonolite has some risk. While the heavy exposure of the miners to asbestos dust resulted in mesothelioma and asbestosis, local residents of the Libby area who experienced only light exposure to dust from the mine also became ill.

Some indstrial hygiene experts feel that any disturbance of Zonolite insulation, even through ordinary household activities like moving boxes that are stored on attic rafters or changing a ceiling light fixture, will release asbestos fibers which can then be inhaled.

Zonolite was manufactured and installed in U.S. homes from 1963 until 1984. The Census Bureau estimates approximately 35 million homes were built from 1963 through 1984. Estimates of the number of houses with zonolite insulation range from 12 million to 35 million.

Homeowners can often identify vermiculite attic insulation; vermiculite is a loose lightweight pebble-like material. The asbestos product originally was golden or light brown in color but over the years typically changes to a shade of gray. Replacing Zonolite insulation requires the assistance of professionals and is an expensive undertaking.

After a study conducted in Vermont, the EPA recommends that homeowners with Zonolite vermiculite insulation not disturb the insulation and hire professionals for removal if replacement insulation is installed.

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