Asbestos in Zonolite Insulation

Sold from the 1940s until the 1990s, Zonolite insulation became the trademarked name for vermiculite attic insulation. Unfortunately, this product was also highly toxic because of its asbestos contamination. Manufacturers produced this insulation as loose-fill insulation that was poured onto attic floors. While no longer made, because it was so commonly used until the 1990s, it can still be found in homes that were constructed prior to this date. 

The Relationship Between Asbestos and Vermiculite

By itself, vermiculite is not dangerous in the same way that asbestos-based products can cause lung cancer and mesothelioma. Both products, however, are resistant to chemicals and they can be used for fireproofing as well. What sometimes occurs is that the two minerals occur together at the same time. One documented case comes from Libby, Montana, at the W.R. Grace Company mine. This supply of vermiculite was unfortunately contaminated with amphibole. Much of the vermiculite supply in the world came from this vermiculite mine, which resulted in a bad reputation. 

Over 20 years have been spent trying to do cleanup around this mine in Libby, Montana, but the Zonolite insulation used in homes will most likely haunt them for even longer. 

How It All Began

Zonolite first started Libby, Montana nearly 100 years ago. E.N. Alley began business and the Zonolite brand was born. Four decades past and in 1963. E.N. Alley had his business acquired by W.R. Grace Company. During the takeover, W.R. Grace Company ignored some of the fundamental problems with this business. The fact that miners were getting lung diseases and dying became a serious problem. Even throughout the 1970s, W.R. Grace Company continued to expand as a company, but they saw a raging fury of lawsuits to follow that led to them filing for Chapter 11 Bankruptcy in 1982. 

An estimated 200,000 tons of asbestos-based materials were processed at this mine and these fibers were so toxic that it sickened the entire town of Libby. The mine finally shut down its operations in 1990, but it was too late for the W.R. Grace Company. Lawsuit after lawsuit eventually brought this company to its knees. In 2002, the EPA declared the mine a superfund site. Homeowners are now advised to take exceptional precautions if they encounter Zonolite insulation in their attics.