Zonolite Insulation

Zonolite Insulation

Years Produced: 1940 – 1980

Zonolite Insulation is the trademarked name of a product sold as attic insulation between the 1940s and 1990s. Consisting of the naturally occurring mineral vermiculite, Zonolite was used for decades to insulate millions of American homes.

This attic insulation was typically gray-brown or silver-gold in color, consisting of a pebble-like texture. Part of its popularity within the construction industry stemmed from the fact it was lightweight and fire-resistant.

Although all vermiculite does not consist of asbestos, Zonolite insulation was tainted with asbestos. Zonolite may prove harmful to residents because it remains in many attics and homes across the United States and the world. Removing Zonolite as a do-it-yourself project should not be attempted because the material contains high amounts of asbestos.

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History of Zonolite Insulation

At A Glance

  • Places Used: Attics
  • Toxicity: High
  • Asbestos Use Banned: No
  • Friable: Yes

The history of Zonolite insulation can be traced back to the early years of vermiculite mining. E.N. Alley owned vermiculite mines in Libby, Montana, where much of the mineral was mined during the early to late-1900s.

In 1963, W.R. Grace purchased the vermiculite mine from the Zonolite Company. Some estimates predict that the company processed nearly 200,000 tons of vermiculite each year. The mine was closed in 1990.

Meanwhile, the executives of W.R. Grace were fully aware of the risks associated with asbestos exposure and did nothing to protect them, which allowed their employees to fall ill. W.R. Grace no longer manufactures asbestos-containing products and focuses on developing chemicals, materials and technologies.


Most of the vermiculite used for Zonolite was found to contain some of the most toxic forms of asbestos. According to reports, tremolite asbestos was found in portions of vermiculite, possibly being 10 times more carcinogenic than chrysotile asbestos (which is the more common form).

Some estimates project as many as 35 million U.S. homes, buildings and offices contain asbestos-containing Zonolite Insulation. There is no official account of the number of families and individuals that may be affected by exposure to Zonolite.

The Environmental Protection Agency (EPA) has known about the dangers of the contaminated insulation product for more than a decade, yet has not taken steps to warn and inform consumers who may have Zonolite insulation in their attics and buildings. A home with asbestos-laced insulation could yield mild to moderate asbestos exposure over many years. This long-term exposure increases the likelihood that a resident of the home will develop mesothelioma, lung cancer or another asbestos-related disease such as asbestosis.


Individual lawsuits and class action lawsuits were among the many legal claims filed as a result of asbestos exposure to this attic insulation product. With the insulation present in as many as 35 million American attics, legal repercussions for former Zonolite insulation-owner W.R. Grace was once tremendous. In fact, the company was named in over 112,000 asbestos-related lawsuits.

In 2008, W.R. Grace settled a class action lawsuit filed against the company to the tune of $140 million. The payment for this claim, which must be paid out over a 25-year period, will go towards the cost of abatement, property-related damage and general compensation.

Abating Zonolite Insulation

Handling asbestos-containing Zonolite is a dangerous task that must be performed with caution. The EPA and other experts made recommendations for consumers who may possess the product.

According to the environmental agency, it is advised that you don’t disturb Zonolite insulation material and don’t attempt to remove the insulation yourself if you are not a trained professional. Don’t store any items in the area where the insulation may be and avoid allowing anyone to go in the attic unless completely necessary. Consult or hire a professional asbestos contractor to assist with any removal, renovations or remodeling of parts of the home that may affect the attic.

Fast Fact: Between 1919 and 1990, 70 percent of the world’s supply of vermiculite came from the asbestos-contaminated Libby mine, according to the U.S. Environmental Protection Agency.

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Matt Mauney is an award-winning journalist with nearly a decade of professional writing experience. Prior to joining The Mesothelioma Center as a Content Writer in 2016, Matt spent three years as an Online Producer for the Orlando Sentinel.

  1. Ewing, WM, Hays, SM, et al. Zonolite attic insulation exposure studies. International Journal of Occupational and Environmental Health. (2010 July-September). Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/20662420#
  2. Environmental Protection Agency – Protect Your Family from Asbestos-Containing Vermiculite. (2010 November 30). Retrieved from http://www.epa.gov/asbestos/pubs/verm_questions.html
  3. Environmental Protection Agency – Vermiculite. (2012 July 10). Retrieved from http://www.epa.gov/asbestos/pubs/verm.html
  4. Schneider, A. Killer in the Attic: EPA Still Evades Zonolite Warnings. AOL News. (2010 December 8). Retrieved from http://www.aolnews.com/2010/12/08/killer-in-the-attic-epa-still-evades-zonolite-warnings/
  5. Schneider, A. White House budget office thwarts EPA warning on asbestos-laced insulation. St. Louis Post-Dispatch. (2002 December 29). Retrieved from http://www.citizen.org/documents/zonolite.pdf
  6. DSP Inspections – Vermiculite Insulation. (n.p). Retrieved from http://www.dspinspections.com/vermiculite_insulation.htm
  7. Schneider, A. Canadian Who Lost Five Family Members to Asbestos in Zonolite Insulation Wants Government to Warn Others. SeattlePI Blog. (2008 February 25). Retrieved from http://blog.seattlepi.com/secretingredients/2008/02/25/canadiian-who-lost-five-family-members-to-asbestos-in-zonolite-insulation-wants-government-to-warn-others/
  8. Great Falls Tribune – Q&A Zonolite? Vermiculite? Asbestos?. (2004 March 8). Retrieved from http://www.greatfallstribune.com/news/stories/20040308/localnews/45301.html

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