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. It only takes being exposed to asbestos one time to get mesothelioma and other lung diseases. Some of these illnesses can take 20-40 years to show symptoms after exposure. Visit the Mesothelioma Cancer Alliance website for more information.

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.

Further Information


  1. 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. 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. 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. 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?

    • Peter,
      Vermiculite has been around since the 1800s, but most of the asbestos contaminated vermiculite found in homes dates from the early 1920s to 1990.

  5. Hi
    I’m writing from the UK, could you tell us whether the vermiculite used for attics over here will be contaminated with asbestos as well, or is this just a USA problem?

    Thank you

  6. I work in a huge drywall manufacturing company/mine and we often use fine powder form vermiculite for our board. Should I be concerned with coming in contact with airborne vermiculite? Should I assume this type of vermiculite is contaminated with asbestos?

  7. We are currently buying a home. Our home inspector found vermiculite asbestos in the attic (about 2 inches thick). This is a flip house. The owners put in canned lighting and
    Exhaused fans. Also the bathrooms were taken down to the studs. Is this something we should be worried about and back out of the deal? We love the house.

  8. Wow, asbestos does a lot of damage! It almost seems unavoidable if breathed in. What if you’ve had it in your home for several years? My home was built around twenty years ago. It’s probably a safe idea to get it checked for these tiny fibers.

  9. This is such a useful and important article! In my old work place we actually had to have an abestos awareness training course as we were based in an old building and so there was a risk of abestos. I didn’t even know what abestos was, or about the dangers it poses until then! I read recently that breathing in abestos kills 4500 people a year while at work so I think it’s really important that more people are made aware of this! That’s why articles like this, and services such as yours need to be circulated more! Keep up the great work! (If anyone is actually interested in doing an awareness course – I believe my old work used Safety Services Direct?

  10. Me and my partner had a hole in living room ceiling from where it had collapsed I cleaned loads of it up with no protection had no idea what it was an so worried now that it is poisoning our air in the house cause we cant fix the hole due to small roof leak so scared we have put our selfs and our baby at risk. Living there for a year luckily we are moving out very soon but am scared that we are all at high risk can anyone help

  11. I recently installed a ceiling fan where a chandelier used to be and had vermiculite fall out of the opening when I took down the chandelier. I didn’t even know what vermiculite was until I looked up why gravel was in my ceiling…
    I am a little bit concerned that I exposed my family to asbestos, however this was a couple of months ago now. Should I assume the contamination is still active, or would any harm have already occurred at this point? I at least know for the future but want to see if a project 2 months ago could still be contaminating the house.

  12. There is vermiculite coming out of two walls in my house where they installed heaters before I bought it 13 years ago. At one point a whole bucketful accumulated in one room I cleaned it with a Dyson hepa vacuum not knowing what it was but it clogged it and I took it apart and breathed in the dust as well as whenever I emptied the bag less canister. Thank God I’m not a good housekeeper and since it’s along the baseboards behind furniture I’ve only cleaned it up sometimes with a dustpan a handful of times over the years. I’m going to get someone to clean it up and seal the walls but I’m afraid it’s embedded in clothes and everything. Should I be worried.? It looks like the accordion type metallic asbestos kind house built before 1980. There is only a few tablespoons under there since I cleaned it out and one room only accumulated about half a cup. One had about a quart. The other a couple of gallons! It’s in the carpets so I guess I should have them taken out too? Should I be worried it’s in everything?

  13. My daughter is considering purchasing a home built in 1956,which has vermiculite insulation.Not knowing the history of the home and any possible previous remodeling projects, would it be a safe investment.

    • Hi, Chuck! Asbestos is dangerous to you when it is disturbed. Without knowing the full details of your home’s setup, it’s best to contact your local asbestos remediation contractor. They are available to handle the safe removal of asbestos material.
      Good luck!


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