Home Improvement Expert Danny Lipford

Dangers of Asbestos Contaminated Vermiculite Insulation in Your Home

Vermiculite insulation between floor joists in attic.

Vermiculite insulation between floor joists in attic.*

Vermiculite is a popular insulation material, but much of the vermiculite used in the U.S. during the 20th century was contaminated with asbestos. Removal of vermiculite insulation can be costly and complicated; but in some cases, you may be able to leave the material in place with proper precautions.

If your home or office has vermiculite insulation, here’s what you need to know to protect yourself from exposure to dangerous asbestos.

The Vermiculite/Asbestos Connection

Vermiculite is a natural flaky mineral (similar to mica) that expands like popcorn when heated. Vermiculite is used in insulation, fire retardants, cement aggregate, fertilizer, and potting soil. The most popular vermiculite insulation in the U.S. was sold under the brand name Zonolite by W.R. Grace & Co.

Vermiculite insulation granules

Vermiculite insulation granules.*

Until 1990, most of the vermiculite sold in the U.S. came from a mine near Libby, Montana, that contained a deposit of asbestos which contaminated the vermiculite.

Asbestos is a mineral fiber that can easily become airborne and causes serious lung diseases such as asbestosis, mesothelioma, and other types of lung cancer.

The Libby mine was closed in 1990, but not before contaminated vermiculite insulation made its way into millions of homes and buildings. The problem is so widespread that the EPA recommends that all vermiculite insulation should be assumed to be contaminated with asbestos.

Indentifying Vermiculite Insulation

Vermiculite insulation is pretty easy to identify. It’s pebbly and loose and resembles very lightweight gravel or small packing peanuts. Most other types of insulation are fibrous or woolly.

Vermiculite insulation may be poured inside framed walls or cinder (concrete) block walls, as well as spread out between attic rafters or under floors.

How to Deal with Vermiculite Insulation

If you find vermiculite insulation in your home, the most important step is not to disturb it. Asbestos is only a danger if it becomes airborne. Sometimes the best solution is to leave the insulation in place, and take steps to protect your home against any airborne asbestos particles.

In dealing with existing vermiculite insulation in your home:

    Vermiculite insulation granules next to paper clip for scale

    Vermiculite insulation granules.*

  • Assume Asbestos Contamination: There’s no firm cut off date for asbestos contaminated insulation; so to be safe, treat all vermiculite insulation as if it contains asbestos. Testing is expensive and inaccurate, and the probability of asbestos contamination is so great, that the EPA recommends erring on the side of caution rather than testing for asbestos.
  • Do Not Disturb Vermiculite: Never stir, handle, or move vermiculite insulation, or do anything to it that might create dust. Even small movements can send asbestos particles into the air. If the asbestos is undisturbed, and it’s sealed away from your home’s living space (such as in a ventilated attic or inside the walls), many homeowners decide to leave vermiculite insulation alone, rather than spending thousands of dollars on remediation.
  • Professional Asbestos Removal Contractor: If you’re doing remodeling that will stir up vermiculite insulation or you want to remediate the building, be sure to hire a professional asbestos removal contractor. Professional negative pressure systems can protect your living space from air contamination during the removal process. At the very least, have someone inspect your home to make recommendations for encapsulating the insulation and preventing leakage.
  • Vermiculite insulation granules

    Vermiculite insulation granules.*

  • Keep Out of Contaminated Areas: Don’t store anything in attics insulated with vermiculite, and make the area is off limits.
  • Seal Off Vermiculite Insulation: Make sure any area containing vermiculite insulation is sealed off from the interior of your home. Use caulk or spray foam around seams, light fixtures, fans, and switches, as well as plumbing pipes or other openings where insulation dust might filter in. Hire an asbestos contractor to install attic flooring that completely covers and seals off the insulation.
  • Warn Workers About Vermiculite Insulation: Talk with anyone working on your home to make sure they understand the risks of working around vermiculite insulation. Special precautions should be taken before cutting a hole in the walls or ceilings if the vermiculite insulation might be disturbed. You may also want to put up signs in the attic, as a warning to workers who may disturb the insulation by accident.
  • Wear Protection Around Vermiculite Insulation: If you must be exposed to the insulation for even short periods of time, wear goggles and a HEPA respirator (not just a dust mask). Walk only on the floored part of the attic, and don’t touch or disturb the vermiculite particles. Clean up small amounts of dust with a wet cloth or HEPA filtered vacuum. However, remember that it’s much better not to have ANY contact with vermiculite insulation!

*Photos from the Environmental Protection Agency.

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4 Comments on “Dangers of Asbestos Contaminated Vermiculite Insulation in Your Home”

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  1. rosalinda zepeda Says:
    September 21st, 2011 at 3:47 pm

    my husband works doing weatherization and is constantly doing insulation for houses,apartments,and other types of buildings. Do i need to be worried about him being exposed to vermiculite and asbestos? What warning signs should I be looking for regarding his health? I know lately he hasn’t been feeling well. what should he do if he’s been exposed? I know today for example that he was exposed, he was wearing a respirator however atfer about 10-15 min he had to get out of the attic because he was having a hard time breathing. he sent me a picture and i could se it was all over him,it was even on his arms and did make full skin contact with his hands. What do we do?

  2. Phyllis Donovan Says:
    April 2nd, 2012 at 5:58 pm

    Vermiculite insulation fell into my daughter’s house from a hole in the ceiling. We did not know anything about asbestos contamination at the time. We cleaned it up like it was just dirt. How long would asbestos stay in the house if it was contaminated vermiculite? The previous owners had work done to the kitchen celing, and I’m sure some must have fallen into the room as well.

  3. Chris Says:
    April 28th, 2012 at 12:28 pm

    If a home has vermiculite asbestos in the attic, would you recommend this as a property that should not be lived in or purchased. Can these homes be safely remediated and is it best to have the old insulation removed by a licensed asbestos professional?

  4. N. DUNLAP Says:
    December 9th, 2014 at 4:41 am

    We have lived in this house for 40 years. It has vermiculite insulation in the attic. About 20 years ago I had additional insulation blown in to the attic that covered the vermiculite. I occasionally worked in the vermiculite. I installed sofett covers and did electrical rewiring over the 30 to 40 years I have lived here. I only wore a dust mask , sometimes not. should I worry?

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