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FAQs About Vermiculite 

Author: Sam "Butch" Nigro

Q. Is all Vermiculite harmful?​

At Dudley, we dispose of all vermiculite of unknown origin as an asbestos containing material, regardless of any test results showing percentages of asbestos content below 1 percent.  Our independently funded Transmission Electron Microscopy (TEM) testing of vermiculite from hundreds of attics has consistently verified the presence of regulated (chrysotile) and unregulated Libby Amphibole Asbestos (LAA) asbestos fibers.  This data leads us to conclude that treating each project as an asbestos abatement project is the correct path to take due to the potential risk of exposure when disturbing vermiculite and the dust it contains.

Q.  What is Vermiculite? 

 Vermiculite is a naturally occurring mineral (basically, it's a rock) that has a high moisture content and the unusual property of expanding into accordion shaped pieces when heated. The "expanded" vermiculite is a light weight, fire-resistant, absorbent, and odorless material widely used by industry in the past and is currently processed in factories around the world and here in the United States. These unique molecular properties allow vermiculite to be used in a wide variety of products, most notably as a popular attic insulation called "Zonolite".  Surprisingly to some, vermiculite is still sold in stores today.  However, the vermiculite we may purchase at the local nursery as a soil conditioner should have been tested frequently and should not contain asbestos.   Look to this website for clarification:   The main concern these days is with a particular vermiculite ore that originated from a certain mine(s) in Libby, Montana.  Unfortunately, this mine had vermiculite ore mixed with Libby Amphibole Asbestos (LAA) and was processed, bagged and installed in well over 20 million attics & homes throughout the United States and the world. Estimates conclude that approximately 75 to 80% of the vermiculite installed in attics, up until the mid 1990's, originated from this mine.   The most common brand name for the vermiculite that originated from this mine was a product named "Zonolite".  The Zonolite Company started producing its Zonolite brand in the 1920's in Libby, Montana and sold its operations to WR Grace in 1963.

Q. How Do I Know If I Have Vermiculite Insulation?
Vermiculite attic insulation is a pebble-like, pour-in substance that is usually light-brown or gold in color. For pictures of the material click HERE.  If you are not sure whether you have vermiculite in your attic please call us to arrange for an inspection.   Vermiculite is not always easy to see.  Often, other forms of insulation may have been installed over the vermiculite.  Unfortunately, the only way to be sure is to enter the space and physically lift or dig into existing insulation.  We highly recommend donning proper respiratory protection while looking for vermiculite in the confined spaces attics present.  In many instances vermiculite may have fallen into wall cavities or pipe chases and can be seen in lower areas of a dwelling.  Following plumbing/chimney chases, looking at lighting fixtures and up on basement sills are common areas where the material may fallen and become visible.

Q. Should I Test The Vermiculite for Asbestos Content?

  At this point in time, according to the EPA, since there is no current standard testing protocol availalble for quantifying the percentage of asbestos fibers in vermiculite we should move forward assuming ALL vermiculite (of unknown geological origin) previously installed in attics/walls..etc contains asbestos. However, If you do choose to have the vermiculite tested for asbestos content we strongly recommend finding a lab that has extensive experience identifying asbestos containing fibers within vermiculite:  is a lab known to have experience in this realm.    The Massachusetts DEP has a guidance document that explains a bit more about vermiculite testing (page 13)

If the decision is made to test vermiculite for asbestos content we recommend utilizing the ASTM TEM Qualitative Test for identifying Libby Amphibole Fibers in Vermiculite as the test of choice (determining a percentage of asbestos content in vermiculite is not feasible at this time according the the EPA ).

Here is a microscopic view of a single piece of Vermiculite 

Each piece of vermiculite has hundreds of layers where toxic 

Libby Amphibole Asbestos (LAA) fibers and other types of 

asbestos fibers were "geologically" lodged for millions of 

years.  According to the EPA, testing each layer for a 

"percentage of asbestos content"​ is just not practical or even 

possible with current testing methodologies....not to mention 

some attics will have two or three types of vermiculite from 

different mine origination. 

microscopic view of vermiculite

Q. I had the vermiculite in my attic tested and the lab report states that it contains less than 1% asbestos content? What does this mean?  Should I still treat this as an asbestos containing material?  Is it safe for me to remove it myself? 


   The verification that asbestos fibers are present within vermiculite (in any quantitative  amount/percentage/trace level--below 1%) is, in many "expert opinions", reason enough to consider having the material removed & disposed of properly by a licensed asbestos abatement professional.   We completely agree with this "expert position".   It is a known fact that asbestos was not intentionally "added" to the vermiculite ore originating from Libby, Montana during the processing steps (except for products such as the spray on Monokote 3 product or others as such) rather, asbestos amphibole was geologically mixed in over millions of years.  Veins of Libby Amphibole Asbestos ore were mixed in with the vermiculite ore and is still present in the mines of Libby, Montana to this day.  The mined vermiculite ore was not refined or mixed into a pulp/slurry and then turned into a consistent end product.  Instead, it was randomly milled, placed on railcar, shipped to factories all over the world then superheated in a controlled factory setting (exfoliated) with the end result being that the asbestos fibers were randomly strewn throughout the final product.  This "exfoliation/expansion" and subsequent bagging of the Zonolite vermiculite enabled the release of the geologically trapped microscopic Libby Amphibole fibers into our world once added to our attics or building products.  What this "randomness" means is that current "known" testing procedures often used by labs cannot test for "true percentages" of asbestos content within is just far too random to test using known and established protocols and methods.  The 1% or greater threshold rule that is used as the benchmark to gauge whether a material needs to be handled as a regulated asbestos containing material here in MA  really does not offer much help/guidance when dealing with the Zonolite ore/vermiculite attic insulation issue.  Asbestos tiles, asbestos paper, asbestos pipe insulation, asbestos mastic adhesive: all of these products were manufactured/processed as a consistently mixed pulp during their manufacturing process. This type of processing creates a testing scenario where a small representative sample of these "homogeneous" products gives you a very accurate representation of the product "as a whole".  This is not the same for testing a small portion of vermiculite with hundreds of layers.  Labs operators that test materials for asbestos content with knowledge and experience will know (or should know) this to be true and special consideration must be taken when performing any type of analysis on vermiculite samples of unknown geological origination.   

Q. What Can Cause My Family to be Exposed to Asbestos Fibers in Vermiculite? Is it Really a Problem, or Just Hype?

 The vermiculite ore that originated from the mine(s) in Libby, Montana was proven to be contaminated with various forms of amphibole asbestos types now commonly known as "Libby Amphibole Asbestos" (LAA) and there are incredible amounts of published studies addressing these facts.  The types of amphibole asbestos found in LAA  ( Winchite, Richterite & Tremolite) can pose a significant health risk to you, your family and those invited to work in your home if the material is disturbed and then either inhaled or ingested.   When vermiculite (Zonolite ore) is disturbed it can release billions of asbestos fibers into the air which increases the risk of lung cancer, mesothelioma, asbestosis and other asbestos related diseases. If the area containing the vermiculite is avoided and left undisturbed, then risk of exposure to asbestos fibers is decreased. However, for various reasons, it often proves necessary to access an attic area.  Activities such as plumbing repairs, fixing roof & chimney leaks/deterioration, mold remediation from improper venting, solar panel installation, rodent removal, electrical upgrades (knob & tube wiring) or recessed lighting installation, heating/cooling installation/repair/replacement, installing upgraded insulation to prevent Ice damming or a responsible citizen attempting to do their part in the battle against climate change by weatherizing their home... these are some of the reasons that necessitate attic entry.  (Not to mention storing all the holiday ornaments/presents!)  Avoiding entering attics often is just not feasible...which is why we highly recommend that all vermiculite be removed when possible, when in the budget and when the timing is right. For more information from the EPA website regarding vermiculite attic insulation click HERE. ​

This website has some interesting information as well: Informative Website 

Q. What is the Zonolite Attic Insulation Trust Fund?

    As of February 3, 2014, W.R. Grace is funding the Zonolite Attic Insulation Trust. This Trust will run for a minimum of 20 years and will allow for partial reimbursement of the cost to remove vermiculite insulation under the ZAI brand name. If you had vermiculite removed prior to the 2/3/2014 date you are still eligible for claim submission under their guidelines.

Q. Who Can Make A Claim?

   If ZAI was installed into a structure which you own or rented, and you have incurred expenses by either removing, abating, or containing the ZAI, you are entitled to submit a claim. In order for the claim to be successful, you must establish that the vermiculite is the Zonolite ore product, provide documentation of spent funds on removing, abating, or containing the ZAI, and provide proof that you either owned or were a tenant of the structure that contained the ZAI.  We strongly recommend emailing the ZAI Trust with any and all questions about the claims process if you cannot find the answers from their website. ​

Q. How do I go about figuring out if I have Zonolite Attic Insulation and how do I qualify for Positive Product Identification (PPI) for a ZAI Trust Claim?

  If you have a discarded bag of vermiculite in your attic with the label “Zonolite” on it then the chances are very high that all the vermiculite in the space is the Zonolite brand.  Please refrain from stirring up any dust near this product and if you need to go into the space for any reason we recommend protecting yourself with a HEPA filtered mask.  If you do not have an easily identifiable discarded bag of Zonolite in the attic or no other evidence that this is the type of vermiculite present (receipt from purchase), then contact us for an inspection.  Please note, even though you may have a bag of vermiculite that does not have markings displaying the “Zonolite” brand name it is known that other vermiculite processors (exfoliators) purchased Zonolite ore from the Libby Mine (s) and applied their own brand name to the packaging….so don’t be fooled by a label.  If your situation requires that you identify whether your vermiculite is Zonolite we have obtained permission from the ZAI Trust to expedite this process in a shortened period of time (2 weeks or less).   The Lab which handles the sample will be looking for the level of a non-asbestos mineral called Barium.  Fortunately, Barium just so happened to be prevalent within the vermiculite ore which originated from the mine(s) in and around Libby, Montana.  If this level of Barium reaches a certain threshold then it is considered to be the Zonolite ore product.  We are currently not charging a fee for this expedited service.  Our experience with this step is crucial and we will guide you through the process that follows.  The ZAI Trust will also accept samples directly from claimants for this Barium test, yet the turnaround times can take 4-6 weeks (or longer) for verification.  The ZAI Trust does not charge a fee for this service and the cost of mailing the sample to their office in South Carolina is usually $4 to $10.   We strongly urge having us take the sample due to there being the possibility that more than one type of vermiculite may have been added to the attic space over the years.   Sometimes multiple samples will need to be submitted if this happens to be the situation.   Please note: If the vermiculite is shown to have a low Barium count this does not mean that the vermiculite is free of asbestos contamination and a high Barium count does not necessarily mean that the material contains asbestos.  This test is designed to provide "origination" for the ZAI Trust.  For claimants, knowing what the product is allows for informed decisions on dealing with the elevated probability of asbestos contamination. 

Q. How Much Will I Be Reimbursed?

   In short, the Trust will reimburse up to 55% of the total cost of removal, abatement, or containment, and re-insulation, (as long as the re-insulation costs are reasonably related to the size of the vermiculite abatement) with a maximum reimbursement of $5,102.50 at a total cost of $9,277.21   The ZAI Trust has guidelines for what they will and and will not cover in a claim.  Please contact them for clarification. 

Reimbursement Examples:

         If: Total Cost = $5,000.00   ------------- Then: Reimbursement = $2,750 

         If: Total Cost = $7,000.00   ------------- Then: Reimbursement = $3,850

         If: Total Cost =  $9,277.21 -------------- Then: Reimbursement = $5,102.50

         If: Total Cost = $10,000.00 ------------  Then: Reimbursement = $5,102.50

         If: Total Cost = $18,000.00 ------------  Then: Reimbursement = $5,102.50

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