Vermiculite insulation in this attic ceiling may contain asbestos fibers. Asbestos in Vermiculite Building Insulation

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Vermiculite insulation home page:

Vermiculite identification photos, hazards, history, advice: what is vermiculite insulation, how is it identified, & what should be done about potential vermiculite-asbestos hazards ascribed to Zonolite ZAI attic insulation?

This article series explains how to recognize vermiculite building insulation that may contain asbestos fibers.

We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Vermiculite Building Insulation: properties, uses, asbestos content

Vermiculite Insulation particles (C) Daniel Friedman

This article permits visual identification of vermiculite insulation; we include our own as well as US EPA photographs of various forms of vermiculite insulation to assist in recognizing vermiculite in buildings. We describe the history of vermiculite insulation, the asbestos hazard that may be present depending on which vermiculite insulation product is present, and how asbestos is identified in vermiculite insulation.

We give the history of the Libby vermiculite mine, its purchase by WR Grace Corporation, the asbestos-related bankruptcy filing, asbestos abatement cost claims & filings & the current ZAI settlement trust that may assist building tenants or owners with vermiculite removal costs.

We also list other, including current producers of vermiculite insulation. This document assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple visual inspection.

Watch out: vermiculite from some sources contains asbestos and can be an asbestos dust hazard in buildings. Details about the asbestos content in some vermiculite insulation products is found in this article.

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What is vermiculite insulation & where is it used?

Vermiculite insulation still in the original bag in this attic ceiling may contain asbestos fibers.Vermiculite is a mineral (hydrated laminar magnesium-aluminum-iron silicates or hydrated phlogopite or biotite mica) from the phyllosilicate group. Vermiculite looks somewhat like mica in that it includes shiny flat plates of material that can be separated.

Details about the properties of vermiculite are at VERMICULITE PROPERTIES.

Vermiculite has a wide range of uses in industry, construction, packaging, insulation, packaging, even animal feed.

Building owners of older structures that had little or no attic insulation are most-often familiar with vermiculite that was poured into attic floors as a loose-fill insulating product. In some buildings vermiculite may also have been blown into previously-uninsulated wall cavities. See VERMICULITE LOOSE FILL Attic Insulation May Go Unrecognized as a Potential Hazard

In addition to its use as an insulation product and in construction as a masonry fill, a cavity fill, & in concrete blocks, vermiculite is added to soils in horticultural applications and to cement to make a lightweight concrete swimming pool base.

In contemporary building construction (2016) vermiculite is used in lightweight concrete and it has been widely used in spray-applied fireproofing. Spray-on fireproofing takes advantage of the light-weight and fireproof properties of vermiculite.

Older spray fireproofing that also used vermiculite may have employed Libby Amphibole Asbestos (LAA) from the Libby Montana mine: a vermiculite source that contained asbestos in several forms that we list later in this article.

After 1991 spray-applied fireproofing that uses vermiculite would not be expected to use Libby-Montana vermiculite, so it would not be expected to be contaminated with asbestos. Pure vermiculite would not contain asbestos.

Vermiculite is also used in special applications such as industrial filters [17], in ceramics (ground & exfoliated, bonded with calcium silicate to form an unfired insulating layer), as a heat resistant component in brake linings (Yun 2010) and even as a treatment for oil-contaminated waters (Mysore 2005) and as a dessicant (>Spitze 1942).

And as we illustrate below, vermiculite insulation can show up as an insulating layer in many products such as a ceiling light fixture.

Question: Vermiculite insulation used in light fixtures?

Vermiculite insulation in a ceiling-mounted light fixture (C) SE

Your website is terrific and very helpful. I was on there to try to identify something. We removed a front hall lamp, by the entrance, and found some wood like droppings inside the lamp. Please see attached photos. We are not sure what this is but are concerned that it could be dry wood termite droppings. Any ideas? - Anonymous by private email, 2016/09/19

Vermiculite insulation in a ceiling-mounted light fixture (C) SE Vermiculite insulation in a ceiling-mounted light fixture (C) SE


What your photos show looks very much like vermiculite insulation - see VERMICULITE INSULATION.

Anon said:

I will send you a photo of the light fixture when I return home (just writing from the office). The house was built in 1934 (plaster walls, etc.). The light fixture looks something like this (picture from the internet):

Vermiculite insulation in a ceiling-mounted light fixture (C) SE

Mod said:

OK now I understand: that ceiling light fixture is insulating its heat from the ceiling above, perhaps for added fire safety. I look forward to seeing actual photos and with your OK will add this info to our vermiculite and light fixture articles as that will help other readers.

Beware that some vermiculite contains asbestos - avoid making a dusty mess and use damp wiping not a household vacuum cleaner for any spill cleanup.

Anon said:

Would you suggest we have the vermiculite tested for asbestos? We kept a sample.

Mod said:

No. The volume of such a small amount of insulation and thus the hazard are rather small. It wouldn't change what you do.

Identify Vermiculite Insulation - Photographs, Description, Properties

Vermiculite insulation small particles (C) Daniel FriedmanThis topic has moved


Watch out: while it is certainly possible to identify a material as vermiculite or vermiculite insulation by examining it with the naked eye or by examining photographs such as those on this page, one cannot determine whether or not vermiculite contains asbestos simply by looking at it with the naked eye nor by comparing photographs of the insulating material.

To absolutely identify asbestos content in vermiculite microscopic examination using polarized light (PLM) is necessary.

See ASBESTOS TESTING LAB LIST if you need to have an insulation sample tested for asbestos.

Vermiculite Insulation Identification Photographs



Watch out: vermiculite insulation was not only poured into attic floors but also into building wall cavities during insulation retrofit projects. Particularly in older balloon-framed buildings, vermiculite could be poured from the attic right into wall cavities extending all the way to the building foundation top. Vermiculite was also often poured into hollow-core concrete block walls.

Unidentified Vermiculite Insulation Photographs


Vermiculite Insulation Identification Images from the US EPA & Other Sources


Vermiculite Loose Fill Attic Insulation - a Potential Hazard

Vermiculite found on closet floor - now look up (C) David Grudzinski Vermiculite found on closet floor - now look up (C) David Grudzinski

These photographs by David Grudinski illustrate a potential asbestos hazard that merits further investigation.

Loose-fill vermiculite from the attic of this home was found falling through a ceiling opening into the occupied space below.

A cursory inspection of the attic showed fiberglass insulation in the attic floor. The vermiculite was below the fiberlass.

Attic loose fill vermiculite found under fiberglass: test for possible asbestos contamination (C) David Grudzinski

We cannot assert that this is an asbestos hazard but it might be. Common-sense advice would include:

Home inspector David Grudzinski provided more vermiculite insulation photographs now found

at VERMICULITE LOOSE FILL Attic Insulation May Go Unrecognized as a Potential Hazard

Which Vermiculite Insulation Products Contain Asbestos? Does All Vermiculite Contain Asbestos?

Vermiculite insulation photograph for identification (C) Daniel Friedman

Vermiculite building insulation might contain asbestos

Our vermiculite insulation photo (left) from the attic of a home in New York state, shows how you might spot the presence of vermiculite insulation even when most of the attic floor has been covered-over. You'll also notice that while most of the vermiculite insulation particles in this photograph are silver-tan or silver gray, some dark fragments are also present, as well as incidental debris.

Does All Vermiculite Contain Asbestos


Libby Amphibole Asbestos mined at the Libby Montana site until 1990 was formed in the Triassic period (225 million years ago) and contained tremolite asbestos as well as other forms of asbestos including winchite and richerite, two forms of fibrous amphiboles.


Most of the vermiculite in the currently operating vermiculite mines (listed below) was formed 1.5 to 3 billion years ago in the pre-Cambrian and Archaen periods.

See this VERMICULITE MSDS from Schundler[17]

How is Asbestos Identified in Vermiculite Products?

Fibrous tremolite -Walter McCrone McCrone Research

While an expert lab test using polarized light microscopy may be needed to identify the specific type of asbestos fiber, or to identify the presence of asbestos in air or dust samples, many asbestos-containing building products not only are obvious and easy to recognize, but since there were not other look-alike products that were not asbestos, a visual identification of this material can be virtually a certainty in many cases.

Also see ASBESTOS DUCTS, HVAC a field identification guide to visual detection of asbestos in and on heating and cooling system ducts and flue vents.

Also see Micro-Photographs of Dust from the World Trade Center collapse following the 9/11/01 attack. Links to U.S. government and other authoritative research and advice are included.

Non-fibrous tremolite - Walter McCrone McCrone Rersearch

Walter C. McCrone, at McCrone Research Institute published detailed procedures for identifying asbestos by microscopic examination, and identifying which type of asbestos is in a material.

His text and microscopy courses taught at McCrone Research and subsequently at McCrone Institute provided methods for identifying fibrous and non-fibrous asbestos in a wide range of materials.[12]

Dr. McCrones photograph of fibrous tremolite asbestos is illustrated at above left. Like many minerals and some other particles, asbestos, including tremolite asbestos, can occur in both fibrous (above left) and non-fibrous (below left) forms.

What to Do About Vermiculite Building Insulation


The best way to minimize your risk of amphibole asbestos exposure is to avoid disturbing vermiculite-based insulation in any way. If vermiculite-based insulation is contained and not exposed to the home or interior environment, it poses very little risk.

Zonolite Brand Vermiculite Insulation, ZAI (Zonolite Attic Insulation) Dust & Tremolite Asbestos Hazards

Vermiculite insulation still in the original bag in this attic ceiling may contain asbestos fibers.

This discussion has moved to a separate article.


Watch out: Depending on the mine from which this mineral-based insulation was obtained, vermiculite insulation may contain asbestos fibers (including tremolite asbestos) and could present a hazard in buildings, especially if disturbed during renovations.

The U.S. EPA has photos of the original bags in which this product was shipped - you're not likely to see these bags in a home, though I've found them on occasion as you'll see in our own photograph of a Zonolite Insulation Fill bag shown at left.

As we discuss at our notes on other loose-fill insulations such as mineral wool or cellulose, any building insulated with loose-fill or spray-in insulation may benefit from the ability of these loose materials to fill gaps and openings more uniformly than might be found if sloppy workers are careless about installing insulating batts.

Munn & Steele Vermiculite Insulation, Siscoe Vermiculite Mines, & Mica-Fill Vermiculite Insulating Products

Moved to MUNN & STEELE VERMICULITE, MICA-FIL, Siscoe Vermiculite Mine

Current Vermiculite Mines & Companies Providing Vermiculite Insulation

Chinese vermiculite from the Leijie Trade Co., Ltd.

Vermiculite mining operations are found world-wide but the largest currently operating vermiculite mining operations continue in

Some Current Producers and/or Vendors of Vermiculite Products

Contemporary Uses of Vermiculite Insulation

Hazards from Incidental Exposure to Vermiculite


Vermiculite & Vermiculite Mining & Uses

Uses of vermiculite were explored as early as 1824 by Webb, appearing the very next year in Robinson's catalog of American minerals. (Robinson 1825).

Please see details about the history of vermiculite at HISTORY of the DISCOVERY & CHARACTERIZATION of VERMICULITE.

Properties of Vermiculite Insluation

Moved to a new article at VERMICULITE PROPERTIES

Research on Asbestos in Vermiculite

Contributor & Technical Review


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