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Vermiculite Insulation | When Was It Last Sold/Installed?

Vermiculite insulation has a poor reputation for those living in North America, and for good reason. A large percentage of US vermiculite insulation is highly dangerous to you and your household.

The question is, is your vermiculite part of the small percentage that came from asbestos-free sources, or is your home in the majority that came from the contaminated mine? Your insulation may be safe if installed after Zonolite was no longer available, but this must be confirmed.

The production of the asbestos-tainted Zonolite ceased in 1984. There is no record of Zonolite being removed from the market at any point. Since it is no longer used in the US, it must be assumed the insulation contains asbestos unless proven safe.

Vermiculite Insulation Still Exists

It’s important to know that vermiculite is a naturally occurring mineral that is not inherently toxic as an insulating material.

Vermiculite insulation still exists in the US from old installations. It is also still used in other parts of the world because there are no health risks associated with the mineral itself.

The danger you might associate with vermiculite insulation is due to a single mine in Libby, Montana, that contained asbestos (including tremolite) deposits that contaminated the mineral supply. Vermiculite was found there in 1919, with commercial selling starting in 1921.

Close-up of vermiculite insulation

Unfortunately, this particular mine was used to supply an estimated 70% of vermiculite insulation to North America from sometime in the 1940s to 1984, when the company cut off production.

This insulation is still present in homes, and while not all the vermiculite on the market at the time was dangerous, the majority of it (even sold under house brand names) was Zonolite. As such, any vermiculite should be treated as though it contains asbestos.

Zonolite Vermiculite Insulation Was Discontinued

The contaminated vermiculite insulation from Libby, Montana that dominated the North American market was sold under the name Zonolite, even after a change in ownership (W.R. Grace & co.) in 1963.

Shockingly, evidence indicates that the W.R. Grace Corporation was aware of health issues associated with the mine when they acquired it and the Zonolite brand and continued to sell the product until 1984, even potentially covering up some proof of the danger during that period.

The mine shut down in 1990 because of the contamination. The town of Libby was severely and tragically affected by the asbestos. It became a Superfund site in 2002, and eventually, in 2009, a public health emergency was declared for Libby. 

I found no proof or even mention of Zonolite being banned or pulled from the market. I can only state that several sources indicate the insulation was no longer produced after 1984.

Information regarding the government’s action on the Zonolite situation is difficult to find, especially dates and exact actions. There was seemly a lot of politics involved in taking action and issuing warnings.

I do know that it was 2003 before the Environmental Protection Agency (EPA) was able to notify the public and inform them on how to manage the insulation.

US Vermiculite Insulation Sales and Installations

As I said, there is not a lot of information on the end of Zonolite, meaning it is difficult to determine when Zonolite and other vermiculite insulation stopped being sold and installed. There is also no record of the product being removed from the market to put a deadline on its usage.

While we know when Zonolite production stopped and when the mine was officially closed, we don’t know how much stock stores and companies had. This could have been used up the same year that production stopped, or it could have continued being used for a few years after.

Is Vermiculite Insulation Still Available?

Other vermiculite products are still sold under strict regulations and testing to ensure that there are no contaminants and that they are safe to use. However, vermiculite is not used for construction and insulation in North America anymore.

It is understandable that with so much Zonolite still out there in homes, people are likely to be skeptical of any vermiculite and the potentially severe risks.

Zonolite Attic Insulation and vermiculite insulation

While it is still a legitimate insulator elsewhere in the world, it wouldn’t necessarily be well-received in the US since finding it in your home, school, or office can be a scary discovery as you would have assumed it is the old, unsafe Zonolite.

Vermiculite Insulation | Does It Need to Be Removed?

Non-US Sales and Installation

While vermiculite from the mine near Libby in Montana was distributed outside of the US, this was in small amounts. Therefore, aside from Canada, the negative image of vermiculite insulation from asbestos contamination is mostly limited to North America.

Since the material itself is a decent insulator with no evidence of inherent health risks, you will still see it sold and installed in other parts of the world.

In addition to the geographically limited contamination event, vermiculite is regulated and tested for use in Europe, meaning that the material is verified as safe.

If you are moving outside of the US and come across vermiculite insulation, you don’t need to worry about asbestos fibers coming from the material. If the mineral were tainted in any way, the authorities would never have cleared it for use.


If you are in Canada, there may be some concern that older insulation came from the contaminated mine. However, unlike in the US, not all of the vermiculite insulation came from Libby since there are vermiculite mines in Quebec and Ontario, which are also potential sources.

As in the US, official sources in Canada provide information on tainted vermiculite insulation and how to handle it.

Living With Vermiculite Insulation | Risks and Precautions


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