W.R. Grace / Zonolite
Zonolite was vermiculite attic insulation contaminated with tremolite asbestos from the Libby, Montana mine.
Description
W.R. Grace and Company's Zonolite brand is at the center of one of the worst environmental health disasters in US history. Zonolite vermiculite attic insulation, sold from the 1960s through the mid-1980s, was produced from ore mined at Vermiculite Mountain near Libby, Montana. The Libby vermiculite deposit was naturally contaminated with tremolite and other amphibole asbestos minerals, meaning that every bag of Zonolite insulation contained asbestos fibers.
W.R. Grace acquired the Libby mine in 1963 from the Zonolite Company. The mine supplied approximately 80% of the world's vermiculite, and the processed product was sold primarily as loose-fill attic insulation under the Zonolite brand. An estimated 15 to 35 million homes across the United States had Zonolite insulation installed, making it one of the most widespread asbestos exposures in residential settings.
The health impact in Libby, Montana was catastrophic. Miners and their families, as well as residents of the town, were exposed to amphibole asbestos fibers from mining operations, processing plants, and contaminated waste used throughout the community. Hundreds of Libby residents developed asbestosis, mesothelioma, and other asbestos-related diseases. The EPA declared Libby a Superfund site and conducted a massive cleanup operation.
W.R. Grace was aware of the asbestos contamination in its vermiculite from the 1970s onward but continued operations and did not adequately warn workers or consumers. The company filed for Chapter 11 bankruptcy in April 2001, citing approximately 65,000 pending asbestos-related personal injury claims. After a protracted bankruptcy process, W.R. Grace emerged from Chapter 11 in 2014, establishing the WR Grace Asbestos Personal Injury Trust and the Zonolite Attic Insulation (ZAI) Trust.
The ZAI Trust is specifically designed to reimburse homeowners for the cost of Zonolite insulation removal from their attics, paying up to 55% of eligible removal costs. W.R. Grace also manufactured MonoKote, a sprayed fire protection product that contained asbestos in earlier formulations.
Countries where commonly found
Commercial brands
How to identify
Zonolite attic insulation appears as loose, lightweight granules resembling small, accordion-shaped pebbles, typically grey-brown, silver-gold, or dark brown in color. The granules are 2mm to 8mm in size and feel light and papery when handled. In attics, the insulation is usually poured between ceiling joists to a depth of several inches. Older bags may still be present in the attic space, bearing the "ZONOLITE" brand name, the W.R. Grace logo, or the text "Zonolite Attic Insulation." Not all vermiculite insulation is Zonolite, and not all vermiculite contains asbestos — but because Libby supplied such a large proportion of US vermiculite, the EPA recommends that all vermiculite insulation be presumed to contain asbestos unless tested. Do not disturb the insulation or walk through the attic without precautions.
Health risk & friability
This material has a risk level of 4 out of 5.
It is classified as friable, meaning asbestos fibers can be released into the air with minimal disturbance. This makes it one of the more dangerous asbestos-containing materials. Any work on or near this material should only be carried out by licensed professionals with appropriate containment measures.
What to do if you find this material
If you find vermiculite insulation in your attic that may be Zonolite, the most important step is to leave it undisturbed. Do not attempt to remove it yourself, and minimize time spent in the attic. Do not use the attic for storage, and avoid any renovation work that might disturb the insulation. The EPA recommends that homeowners assume all vermiculite insulation may contain asbestos. If you need to remove the insulation, hire a qualified asbestos abatement contractor. The Zonolite Attic Insulation (ZAI) Trust, established by W.R. Grace, may reimburse up to 55% of eligible removal costs for qualifying homeowners. Visit the ZAI Trust website to check eligibility and file a claim before beginning removal work.
Frequently asked questions
Does all Zonolite contain asbestos?
Can I get money to remove Zonolite insulation?
What happened in Libby, Montana?
Is it safe to live in a house with Zonolite in the attic?
What is the difference between Zonolite and MonoKote?
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