Understanding Vermiculite - American Society of Home Inspectors, Inc.

What is vermiculite? It was first named in the early s after an occurrence in Millbury, Massachusetts. Vermiculite has been mined in the US, Brazil, Uganda, Australia, Russia, and Canada, and it’s formed by the weathering of hydrothermal alteration of biotite, or iron-bearing phlogopite.

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The word vermiculite comes from the Latin for “worm breeding” because of its worm-like appearance when it puffs up in high heat. Vermiculite is a naturally occurring mineral composed of shiny flakes, resembling mica, according to the EPA.

Vermiculite undergoes significant expansion when heated; it can increase up to 30 times its original size. You can see visible layers in expanded vermiculite. If you pinch expanded vermiculite, It flattens back to a shiny mica with a silvery gray appearance. 

Vermiculite has been used for many purposes—including loose fill home insulation, gardening soil, brake linings, pool liners, fire-resistant panels, decorative gas fireplaces, and much more. The negative aspect? Vermiculite has been found to be contaminated with deadly asbestos.

The Dangers

Pure vermiculite does not contain asbestos. Impure vermiculite can contain many forms of asbestos—including tremolite, chrysotile, amphibole, winchite, and richterite.
Asbestos contamination of vermiculite was discovered at a mine in Montana after workers’ health concerns were investigated. As a result, the Zonolite Attic Insulation Trust (ZAI Trust) was created to help educate the public about the possible health effects of asbestos-containing vermiculite and to provide partial reimbursement for ZAI removal to qualified claimants. I’ll explain more about that later. And to read a complete history of the Zonolite mine, see the article with in-depth timeline at homeinspector.org/Newsroom/Reporter.

Mine Timeline

(courtesy of High Country News)

 — In an old mine shaft about seven miles from Libby, prospector Edgar Alley notices his candle causing a strange rock to expand; he’s discovered veins of vermiculite, which contains tremolite asbestos.

 — Universal Zonolite Company takes over the vermiculite mine, processing the ore into insulation for buildings around the nation.

 — A state inspector takes air samples in the vermiculite mine and processing mill, and finds that “the asbestos in the air is of considerable toxicity.”

s — Workers handling the vermiculite begin to come down with asbestos-related illnesses.

 — Multinational conglomerate W.R. Grace & Co. takes over the vermiculite operation. Over time, the company improves working conditions to reduce the asbestos risk but allows the exposure of workers and families to continue.

s — The EPA conducts four studies that show the dangers of asbestos in Libby but keeps them quiet.

Mid-s — Ralph Nader’s Public Citizen magazine and Montana newspapers report on asbestos-related illness in Libby and victim lawsuits against W.R. Grace. The national press ignores the story.

 — EPA bans most uses of asbestos nationwide.

 — W.R. Grace & Co. closes its Libby vermiculite operations.

 — Ruling on an industry lawsuit, the 5th Circuit Court of Appeals tosses out the EPA’s asbestos ban, saying the EPA’s cost-benefit analysis is flawed. The George H.W. Bush administration lets the issue drop.

 — Tipped by Montana environmentalists and lawyers, the Seattle Post-Intelligencer makes the Libby asbestos disaster a national story, forcing the EPA top dispatch a cleanup team.

 — W.R. Grace & Co. declares bankruptcy to shield itself from lawsuits filed by asbestos victims nationwide.

 — EPA declares Libby a Superfund cleanup site.

 — Federal Judge Don Molloy in Missoula orders W.R. Grace & Co. to pay $54.5 million to help cover the cost of the Libby cleanup. The company has appealed that verdict.

 — Insurance experts predict that Libby asbestos victims’ medical bills will total $32 million during the next five years. W.R. Grace may pay only one-third of the cost.

 — Sen. Arlen Specter, R-Pa., introduces the Fairness in Asbestos Injury Resolution Act, which would collect $140 billion from asbestos and insurance companies to pay the victims’ medical bills while making the companies immune from lawsuits. The bill wouldn’t cover most of the Libby victims.

 — On Feb. 2, President George W. Bush, in his State of the Union Address, says, “Justice is distorted, and our economy is held back, by irresponsible class actions and frivolous asbestos claims—and I urge Congress to pass legal reforms this year.”

LOGGING AND ENVIRONMENTALISM

s — Mining begins with gold rushes on banks of Libby Creek.

 — Family-owned J. Neils Lumber Co. relocates from Minnesota to Libby, buying sawmills and, eventually, several hundred thousand acres of timberland.

 — J. Neils sells out to the giant St. Regis Paper Co., which later builds more sawmills.

s — Libby’s economy booms, employing more than 1,300 in logging and about 2,000 in constructing the Libby Dam.

 — Local environmentalists organize the Cabinet Resource Group to fight risky mining proposals. Over time, environmentalists oppose heavy-handed logging and stop two additional dams.

 — St. Regis Paper Co. merges with Champion International, which liquidates old growth on the private timberland for short-term profits.

 — Kootenai National Forest logging peaks at 250 million board-feet per year.

s — Environmentalists’ appeals and lawsuits, as well as insect outbreaks and wildfires, cause the Forest Service to reduce the timber cut in the Kootenai National Forest by more than 75% to about 60 million board-feet per year.

 — Champion sells its local timberland to the giant Plum Creek Timber Company. Plum Creek finds a buyer for the sawmills, Oregon-based Stimson Lumber Co., which lays off hundreds of people and closes all but one of the mills.

 — Stimson shuts down the last sawmill in Libby, laying off 200 people, in part because of the skyrocketing cost of medical insurance for workers and families poisoned by asbestos.

 — Lincoln County leaders ask the Ecology Center to drop a lawsuit that has stalled logging on the Kootenai National Forest. The Ecology Center refuses, but Sen. Conrad Burns, R, passes a rider that allows some timber sales to proceed.

 — Five environmental groups file a new lawsuit challenging logging on the Kootenai National Forest. Other lawsuits challenge the same risky mine proposals that began in the s.

 — Jim Hurst, owner of Lincoln County’s biggest remaining sawmill, in Eureka, announces that he’ll shut down in May, laying off 90 people. He blames environmentalists for “obstructing” logging on the national forest.
 

Close Encounters

My first encounter with vermiculite occurred near the start of my home inspection career more than 20 years ago. I do not recall any training or awareness around vermiculite in the course of my becoming a home inspector before I inspected a Rhode Island beach cottage that had asbestos hardboard siding, vinyl asbestos floor tiles, and asbestos pipe insulation on steam heating pipes. I made the standard comments in my inspection report that the home had items known to contain asbestos, and the client was advised to consult an asbestos contractor for further evaluation.

The client did not seem alarmed, but a few weeks later I received a letter from his attorney asking for compensation from me for failing to identify a product known to contain asbestos. I was shocked, as I did report asbestos. I called the client, confused. He informed me that the asbestos contractor told him the vermiculite attic insulation was also contaminated with asbestos. I had no idea, but I immediately investigated the issue and was directed to the EPA website.

The client forwarded the asbestos contractor’s report and information. I read it and kept it handy while doing more research. I called a contact at the Rhode Island Department of Health—an industrial hygienist who oversees environmental licensing, inspection, and mitigation—and explained the situation. The hygienist asked me who tested the vermiculite, and I gave him the information provided by the client. The hygienist told me he would call me back, so I sat chewing my fingernails. I was starting to question whether I was ready to inspect homes. I had been in construction most of my life and felt confident I would be a good home inspector based on my decades of experience in commercial and residential construction. I went to a professional training school for home inspections. I passed the exams with high grades. I passed the national home inspector exam with an almost perfect score. I became ASHI-certified. I knew homes.

The industrial hygienist called me back and said there were several issues. First, any client who knowingly bought a home with asbestos siding, vinyl asbestos floor tiles, and asbestos pipe insulation had very little claim about a fourth product that may contain asbestos. I asked him to clarify “may contain asbestos.” He said they had not proven it had asbestos because the test they did on the vermiculite was done wrong, and the lab result failed to adhere to the EPA protocol. They sampled a single teaspoon full of vermiculite taken off the top surface of the rafter bay. The lab used a standard microscope and not a “PLM” analysis, or polarized light microscopy—the minimum standard for looking at vermiculite for asbestos, and the lab returned a negative result. 

He went on to explain that the EPA mandates that no analytical lab can ever return a negative or “none found” on a report when testing vermiculite. The lab report must include a disclaimer that states “although no asbestos fibers were observed in this sample provided, based on EPA protocol, you must assume the sample to be positive based on the random dispersal of the asbestos fibers, and due to settlement of the fibers in attic insulation.” 

I breathed a sigh of relief and began to read even more about vermiculite. I also emailed the client and his attorney to explain the situation as explained to me by the industrial hygienist. They withdrew their demand.
 
 

A Second Encounter

It would be a few years before I encountered vermiculite again. I was inspecting a Dutch Colonial. The home was close to an international airport and had been soundproofed under a federally funded program to mitigate the sounds of planes flying over the home. The soundproofing included installing central AC since the homeowners were less likely to open the windows on a nice day due to the noise from flights passing overhead. The Airport Corporation also installed a second layer of windows over the existing windows and additional insulation in the attic.

The inspection started out rather typically. I always begin with my exterior walkaround, roof inspection, and then proceed inside to the basement where I begin structural, heating, electrical, and plumbing inspections. When I reached the second floor and opened a closet door I saw silvery gray debris on the closet floor and the shelf above. I looked closer and immediately recognized vermiculite flakes. I looked up and saw the attic scuttle hatch. Vermiculite flakes clung to a felt weatherstrip around the hatch opening. This time I was prepared. I told the client what I saw and that I would need to look around more before going into the attic.

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In another bedroom HVAC ducts traveled through the closet and into the attic. Vermiculite flakes were littered all around the closet and falling through the gaps of the hole where the HVAC duct passed through the plaster ceiling.

I put on my PPE before entering the attic. When I opened the attic hatch, there was vermiculite everywhere. The HVAC unit was sitting in it, as was the unvented bath fan. Personal items and rolled up carpeting were partially submerged in the vermiculite along with plastic bags and other debris. I took many photos. I could see vermiculite seeping out where light fixtures were mounted and inside the housing of the bath fan.

I explained my concerns to the client and their agent, and the listing agent was skeptical, to say the least. “I’ve been selling homes for 25 years, and I have never heard of this before. I’m sure the Airport Corporation contractors would know if there was a danger here” was the sentiment. I compiled my report and advised the clients to consult an asbestos contractor before proceeding. I included links to the EPA website and the Department of Health information.

Ultimately an asbestos contractor did a test on this home, and a similar process unfolded, as the same lab did the same thing again. This time they were fined and sanctioned by the Rhode Island Department of Health.
 

Educating the Industry

I felt something needed to be done to bring awareness to this issue in my area. I wrote my first article on the subject in the February issue of the ASHI Reporter, including photos of the home near the airport and the vermiculite insulation.

Since my first encounter, I have probably discovered vermiculite in 500 homes all over Rhode Island. The ages of homes in Rhode Island start around the mid-s, but based on my observations the homes most likely to contain vermiculite insulation range from the s to around the s.

I have encountered many scenarios where vermiculite was present, and both contractors and homeowners were unaware of the product or its dangers. On several occasions home inspectors who previously inspected a home I was later hired to inspect did not report the presence of vermiculite when it was quite readily visible. In some cases, fiberglass batting was laid over the vermiculite, but there were signs of shiny flakes littered around gaps in the fiberglass batting or around areas that were previously disturbed by storage or recent repairs.

In one situation a home being renovated by a contractor caught fire during the renovation. The firefighters pulled down the ceiling only to have large amounts of vermiculite fall into the home. I arrived to inspect the home as finishing touches were being made and observed two workers sweeping up debris. It was littered with vermiculite, and a cloud of dust hung in the air. I asked the workers to step outside and explained the hazard. To his credit, the owner of the renovation company went out and bought the workers approved respirators and had an asbestos company address the issue. 

More recently I was hired to inspect a s high-end home when, as I reached the attic and opened the access door, I saw the ceiling joist bays were filled with vermiculite. There were some flooring boards, but as with all s era Cape Cod style homes, there were half-inch gaps in the boards. Vermiculite was everywhere. There were some personal storage items in the attic, as well as evidence of recent upgrades to wiring, lighting, and ductwork from recently installed Mini split AC units.

I let the clients and the real estate agents on both sides know my concerns. I showed them the literature and recommended a course of action. The seller’s agent was shocked, as the sellers had hired a home inspector when they bought the home, and nothing was mentioned about vermiculite. The sellers also hired a home inspection company to do a pre-sale home inspection and again, nothing was mentioned. More concerning was the fact that a pipe had burst recently, part of the ceiling fell, and large amounts of vermiculite fell into the home. Significant renovations have occurred to repair that damage and make improvements before sale, and not a single person reported vermiculite or the potential dangers. The homeowners were nervous that no asbestos mitigation or testing was conducted, and they had been living in the home all that time. 

Recommendations

When I discover vermiculite insulation, I advise testing by the Zonolite Attic Insulation Trust, created after the Montana mine discovery mentioned at the top of this article. I recommend reading more about the Zonolite mine in Montana from the Trust as well as reports from the EPA.

If the Zonolite Trust confirms that the vermiculite is from the Zonolite mine, you will get credit for compensation from the Trust. I do not recommend having typical lab testing done, as I feel it does not accurately detect asbestos contaminated vermiculite.

While the EPA recommends leaving vermiculite alone, I feel that’s not realistic. A number of incidents can occur that result in the home being contaminated, such as the earlier incidents I’ve described or a broken pipe, fire, or renovations by contractors unfamiliar with vermiculite contamination, and so on. Any of these situations can result in contamination of the home with a loose harmful asbestos fiber that can cause severe health issues. Why risk it? 

An estimated 70% of the vermiculite insulation installed in homes was of the Zonolite brand. The Trust will compensate up to 55% of the cost of mitigation, and the maximum credit is reported to be $8,972.33 per home. Eventually, though, the fund will run out. It seems ill-advised to leave the vermiculite in the home and worry about potential contamination or that the presence of vermiculite may reduce the home’s value.

Asbestos mitigation removes the contaminated product, provides air testing post mitigation, and confirms the home is asbestos-free. A local mitigation contractor in my area goes one step further and seals the attic surfaces with a sprayed sealer that will encapsulate all surfaces in the attic in case any asbestos fibers were to be stuck to surfaces only to become disturbed in the future.

The presence of marked Zonolite bags provides a simple confirmation that saves time and removes doubt. The presence of the clearly labeled bags made acceptance of the claim through the Zonolite Trust a hassle-free and quick experience. I recommend having a trained asbestos contractor help with the claim process. An asbestos contractor can safely and properly take a sample to submit and maintain an untainted chain of custody. 

I am always available to anyone who wants to reach out with questions or needs guidance. Let’s spread the word. Let’s keep home inspectors safe, and let’s give more informative recommendations to our clients.

People have had problems finding vermiculite because of two reasons:

1. In the early 's the W.R. Grace Company closed its mine in Libby, Montana and over 20 processing plants located across the country. As a result, there are many regions where there simply isn't a local vermiculite processing plant.
2. Because of a lot of bad publicity about Libby and the Libby vermiculite mine, most of the larger "box stores" no longer stock and supply vermiculite.

Nevertheless, vermiculite continues to be used by professional pool contractors, by large greenhouse growers, by industrial fireproofing manufacturers and applicators, by installers of insulation, by industrial manufacturers and commercial businesses.

Unfortunately, homeowners and hobbyist have had problems find sources for relatively small quantities, and so this site has been designed to try to help them find and purchase vermiculite.

We've tried to organize this site by basic areas of interest and/or by applications for which vermiculite would be used. If you have suggestions on other ways to organize this site, or would like to add listings, please contact us. (See address and contact information at the bottom of this page.)

SWIMMING POOL CONSTRUCTION:

Not all vinyl liner contractors and dealers use vermiculite, but first try your local pool stores and dealers to see if they will sell you any regular pool base vermiculite (what we call V+16 Pool Base) or the pre-blended product that is a mix of vermiculite and portland cement (what we call Ultra Mix II). Many dealers will not sell the vermiculite to you since they feel the DIY pool builder is taking away from their livelihood. Nevertheless, try to persuade the dealer that you intend to build your pool one way or the other and you will need to purchase chemicals for the lifetime of the pool, and, therefore, they should help you now in the hope of gaining another good customer.

A typical vemriculite pool bottom
just before the liner is installed.

If that fails, a listing of distributors throughout the country can be found at The Pool and Spa News Online Directory. The distributors usually will not sell direct, but they may tell you the name of a dealer near you who may.

And if that fails, try to see if you can find some vermiculite concrete aggregate at your local lumberyard or masonry yard (not one of the box stores like Home Depot or Lowes since they don't carry perlite and vermiculite aggregates.)

Or, you can try local garden centers and/or greenhouses and see if they can get some fine grade vermiculite for you. The grades used for the horticultural industry range from a fine to an extra coarse, and for swimming pools you want the fine grade.

On the west coast, you will have a lot of trouble finding vermiculite. We recommend you try perlite concrete aggregate and just follow the directions we have for mixing and troweling V+16 Pool Base.

Unfortunately, manufacturers like The Schundler Company normally sell to distributors in our distribution area. As such, we really don't know which local dealers or contractors have our materials or use them. And other manufacturers are the same.

We also aren't set up to handle retail, to ship in small lots, or to have homeowners come to our plant to purchase material.

Nevertheless, if all else fails, we suggest you contact us or locate a vermiculite manufacturer near you.

HORTICULTURE

If you want quite a few bags (4 cubic foot bags) of perlite or vermiculite, we suggest you contact your local garden center or greenhouse, and see if they can help. Don't bother with the large box stores (Home Depot, Lowes, Wal-Mart) since they often stock only small bags, and may not stock any vermiculite. Garden Centers and greenhouse operations purchase materials from distributors who do stock and carry large bags of perlite and vermiculite, and they might help you and/or sell you materials directly.

You can also try regional chains or farm stores like Agway, Pennington Seed, Southern States, etc.

Flowers in Sqaure Foot Gardening ........Or, go to the internet and purchase from sites like:

• 7 Springs Farm
• Carlin Horticultural Supplies
• Morton's Horticultural Products

Sometimes products like our Soilac (for use in outdoor gardens and for landscaping) simply are not available from horticultural distributors. For these grades of perlite, you might want to contact local masonry supply stores and ask for perlite (NOT vermiculite) masonry wall, loose fill insulation. It's usually dusty, gritty, and just what you want for your garden (the fine particles keep the clay loam soils from compacting, and hold significant amounts of water.)

Again, if all else fails, then contact a local manufacturer. There are a lot more perlite manufacturers than vermiculite manufacturers, and the perlite producers can be found at The Perlite Institute. Unfortunately, there is not a readily available listing of vermiculite manufacturers since the Vermiculite Association membership is mostly mining companies and consultants, and most of the major manufacturers in both the United States and Europe are not members.

INDUSTRIAL:

For lab packing grades of vermiculite, industrial grades of perlite or vermiculite, and any other uses, feel free to contact us (: ) or a manufacturer close to you.

Vermiculite: A General Overview

Essentially vermiculite is a member of the phyllosilicate group of minerals, resembling mica in appearance. It is found in various parts of the world, but currently the major mines are located in South Africa, China, Brazil, Zimbabwe, and the United States. The largest operating mines today are located in the Palabora region of North-Eastern Transvaal in South Africa, in the northwestern corners of China, and along the eastern Appalachian range in the United States (Virginia and South Carolina). The vermiculite ores from these mines are different forms of hydrated phlogopite or biotite mica which has the remarkable ability of being able to expand to many times its original volume when heated---a property known as exfoliation.

From a geological perspective, almost all of the commercial vermiculite mines operating today work in deposits which were formed in pre-Cambrian and Archean deposits (1.5-3.0 billion years old). These are quite different from the former Libby, Montana deposit which was Triassic in age (225 million years old).

Recently there has been a lot of confusion about vermiculite and asbestos. To read more about vermicuilte, about its many uses, and or to read some of the many reports on vermiculite, go to:

• The Schundler Company---Perlite and Vermiculite Products since , or
• The Vermiculite Home Page, or
• The Vermiculite Institute, or
• The Vermiculite Association

TYPICAL PHYSICAL PROPERTIES

TYPICAL SIZES, DENSITIES, AND NAMES
OF EXPANDED VERMICULITE1

SIZESDENSITIESGRADES OR SIZES MMIN U.S. Standard
Inch/SieveKG/CU MLB/CU FTU.S. SYSTEMINTERNATIONAL 8 to 165/85/16 to 5/856-723.5-4.5N/APremium (6) 4 to 85/165 mesh to
5/16 inch64-854.0-5.01Large (4) 2 to 45/ mesh to
5 mesh72-904.5-5.52Medium (3) 1 to 20. mesh to
10 mesh75-.7-7.03Fine (2) 0.5 to 10. mesh to
18 mesh80-.0-9.04Super Fine (1) less than 0.50.02less than
35 mesh90-.6-10.05Micron (0) NOTES:

1. These sizes and values are given for general information purposes only. All manufacturers do not necessarily produce all these grades, and many use grades which may not conform to these specifications at all times.

We hope this page has helped! And please recommend links, or make other suggestions that will make purchasing vermiculite easier for others!

The company is the world’s best Expanded Vermiculite supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.