Questions & answers about potential vermiculite insulation exposure levels in residential buildings.

This article series describes reasonable risk assessments for people exposed to vermiculite insulation that contains asbestos (not all does) and that has been installed in residential buildings. Most research on health hazards from asbestos-containing vermiculite insulation has focused on workers at vermiculite mining or processing sites or at communities close to those locations.

Incidental Exposure to Vermiculite: Research & Opinion FAQs

Question: How to assess asbestos exposure hazard from HVAC ducts near Vermiculite Insulation

2019/05/08 Anonymous wrote: Thanks for running this site – very informative resource. I had a home inspection on a house I was planning to buy and the inspector found vermiculite insulation poured down the wall cavities from the attic. The AC line runs along the perimeter of the interior of the roof, above where the vermiculite insulation is visible.

We have a 3yr old, with a baby on the way and felt like passing was the best option. Do you think this was an overreaction?

Reply: inexpensive, practical dust test for objective data on asbestos risk; remaining EnviroScare impact on future home sale

Thanks for the interesting question.

Our photo above shows loose fill vermiculite in an attic close to an air handler and flexible return-duct. Air leaks into the return plenum of the air handler or into the return duct itself or vermiculite dust tracked back into the living area by an A/C service technician working in the attic could pose potential asbestos hazards.

But vermiculite insulation in wall cavities, even if the insulation is one of that subset that contained asbestos (Zonolite, for example) is less-likely to be a detectable asbestos exposure hazard when left alone.

Having inspected thousands of homes in North America over roughly forty years, my OPINION is that it is rarely appropriate to walk from the purchase of a home based on a theoretical worry about a possible hazard such as the one you describe, in which the cost to cure, should the actual hazard be confirmed, would most-likely be a very small percentage of the value of the property.

Rather, I'd have followed up with reliable inspection and testing, and I'd also have wanted to know what other probable repair or cleanup costs the home requires for safe habitable use in order to have a good overall perspective of the actual cost to buy and occupy the home.

Assessing Vermiculite Asbestos Exposure Risk via HVAC Ducts

With the reclama that nobody can give a completely reliable email answer about a possible hazard in a building they've never seen, in general, if we assume - as the most-conservative approach - that your vermiculite insulation contains asbestos and we assume that it's close to HVAC duct work, then the risk of exposing building occupants to asbestos dust from the vermiculite through the duct system would depend on

1. Type of Ductwork whether the ducts are supply (under positive internal pressure) or return (under negative internal pressure ) lines.
2. Duct leaks: whether there are leaks or openings in the ductwork as it passes through or near vermiculite insulation. The duct material itself (flex-duct vs. metal ductwork for example) may also be a factor in risk of future return duct leaks.
3. Air Filtration: the HVAC system air filters: type, location, maintenance, and leakiness
4. Actual occupant exposure level for asbestos: the concentrations of or levels of asbestos dust in the occupied space vs. fresh air and occupant exposure time - in other words, the actual, objective exposure level for building occupants (and of course individual occupant vulnerability)

A leaky return duct passing through or near asbestos-containing vermiculite could in principle draw such dust into the duct system and could thus distribute it into building air. If the system air filters is ahead of that duct passage (such as an air filter at the return air inlet) then the filter, even a HEPA filter, would not prevent the asbestos-dust transport into the living area. If in that case sufficient asbestos dust is drawn into the duct system and blown into the living area, it is possible that a hazardous asbestos dust exposure could occur.

However without any objective data it would be specious to assert that a meaningful hazard is actually present.

See objective data research on actual vermiculite insulation asbestos exposure risk hazard levels found

at VERMICULITE INSULATION INCIDENTAL EXPOSURE HAZARDS ?

Here is one excerpt from the references given there

• [7] VERMICULITE INSULATION CONTAINING, AMPHIBOLE ASBESTOS [PDF], Health Canada, September 2009, web search Jan 2011, source: http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/prod/insulation-isolant-eng.php [copy on file as /hazmat/Vermiculite_Health_Canada.pdf] Vermiculite Insulation Containing Amphibole Asbestos - September 2009, Health Canada Quoting from the PDF document:
  
  Some vermiculite insulation may contain amphibole asbestos fibres. These products can cause health risks if disturbed during maintenance, renovation or demolition.
  
  However, there is currently no evidence of risk to your health if the insulation is sealed behind wallboards and floorboards, isolated in an attic, or otherwise kept from exposure to the interior environment.

Screen For Vermiculite Asbestos Exposure Risk in a Home - first step

So what might you do should this sort of asbestos-exposure-hazard question arise again for the home involved,or for another one?

For an initial qualitative assessment of the possibility of asbestos exposure in your building one might use TAPE & BULK SAMPLING & TESTS for MOLD to sample one or more representative samples of settled dust (from a horizontal surface not recently cleaned, such as trim over a window or door, to see if there are significant levels of asbestos in the dust.

If such is confirmed, then further investigation for the source, and thus decision on the appropriate remedy, would be in order.

If no asbestos is found in representative samples of settled dust - a more-reliable qualitative screen for asbestos contamination than a one-shot "air test" - then the immediate asbestos hazard from the vermiculite source is probably insignificant.

There might still be additional steps appropriate to avoid a future issue, such as testing the actual vermiculite insulation for asbestos and depending on that result either sealing it against accidental tracking (e.g. from attic) into the occupied space, or occasionally, it's removal.

Generally it's safer and also far more economical to leave asbestos-containing materials alone, covering them or sealing them, than to disturb the material.

Finally, in my OPINION, as with many environmental hazard topics that scare people, independent of the actual, objective health risk in such buildings, there remains a fear factor that has an un-deniable economic impact at the time of resale of a home stigmatized by fear of electromagnetic fields, proximity to power lines, prior flooding, mold contamination, asbestos materials, lead paint, etc.

Those concerns mean that some (not all) buyers will be worried just as you were, and in turn for the home seller that can translate into longer time on the market to sell a home or a reduced selling price.

In my experience and opinion those economic effects are almost completely independent of any actual hazard that is, was, or was never actually present in the home.

See details at ENVIRO-SCARE - PUBLIC FEAR CYCLES

Question: is .0004% of asbestos ok to be working in and preparing food in?

I work in a school in mt, and 2 years ago this substance was removed from two rooms in the school, one which is right by the kitchen i work in. well 2 days ago i found this substance on top the the cupboards and everywhere else, and can see that it is falling from the ceiling.

Very concerned because i have a fan blowing in there, and there was asbestos in the school when they came and had it cleaned. my question to you is, is .0004% of asbestos ok to be working in and preparing food in?

i truly found this site excellent, it answered a lot except that one question. thank you - Amy Swanson 9/2/11

Reply:

Thanks for tine nice note Amy.

A proper asbestos cleanup project, especially in a school, should have included post-cleanup inspecting and testing to assure that no asbestos hazard remained. You might want to ask for and read that report.

About the substance falling from your ceiling, if you think it's asbestos-containing material you certainly shouldn't be running a fan, and it would make sense to have it tested for asbestos content.

The % of asbestos number you cite leaves me confused.

If you mean that the general dust from the environment is down to that minimal level, it sounds almost below the limits of detection.

But I don't know what test you are describing, nor where nor how it was performed -those questions are key in understanding what the test results mean.

Your concern should be answered more specifically by a hygienist or similar professional who has specific expertise in asbestos and indoor air quality and who knows the building and its history.

We would much appreciate hearing any comments, critique, suggestions, or further questions from you or other readers. We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Working together and exchanging information makes us better informed than any individual can be working alone.

Reader follow-up:

Well this is my first year at this school, and was told that 2 years ago there was asbestos in the library and the music room and they did have it cleaned up professionally, but they didn't do it to the kitchen.

now this stuff that looks like your picture above with the gold and silver flakes in is is all over my kitchen and my boss told me it wasn't harmful cause they had it tested and it was at .0004%, but my concern is that if they had to clean it out of the other 2 rooms that it should be also done to my kitchen and i have 2 other ladies that work with me and we are all really concerned and are wondering what it is or whom it is that we can contact because everyone is telling us its ok and i don't think it is ok.

my boss is having someone come out there to caulk the ceiling again, and that is it...more or less just sweeping this under the rug. ..i have some of this stuff that fell from the ceiling in a plastic folder. it was hanging on the wall and caught it, but my concern is that i didn't know it was in there at the time i pulled a few papers out of it.

that is how it was brought to my attention of what it was. i am seriously concerned and would just like to know whom it is i need to contact outside the school, since no one in the school seems to really care about it or us.

Question: Zonolite Rolled Glass Fiber Home Insulation

i got zonolite rolled glass fiber home insulation is it safe ? - Concerned

Reply:

Concerned: I don't recognize the product you name - can you send me a photo of the material and of any labels or markings on packaging? Then I can research and comment further. Use the CONTACT US link at page top or bottom to send photos if you can.

Certainly "fiberglass" is not an asbestos material. In our opinion, fiberglass insulation is safe if it has been properly installed and has not been damaged. Severely damaged fiberglass insulation, such as a product that has been walked-upon numerous times, or that has been macerated during demolition, may produce high levels of glass fiber dust, including small particles that may are a respiratory irritant and may be more harmful.

Should I have my Attic Insulation Tested?

I found plastic bags in my attic space that say "Full Fill" Insulation 100% abestos free from Koos Inc. Kenosha, WI. Should I have the insulation tested? - Colleen 3/4/12

Reply: U.S. EPA Koos WI Site Visit Report on Vermiculite & Asbestos Exposure

Colleen, some mesothelioma and asbestosis websites, usually ones seeking to provide legal services, report that workers at Koos corporation in Wisconsin were exposed to dangerous levels of asbestos. The U.S. EPA visited the Koos site in Kenosha, WI on 9 March 2000. Here are two reports from the U.S. Government Accounting Office.

Unknown facility:

An EPA database compiled from W.R. Grace shipping invoices did not contain any records indicating Libby ore was shipped to this site. Because this site was associated with the Koos Inc. site in Kenosha, Wisconsin, EPA visited this site. (The Kenosha site is listed separately in this database) At the time of EPA's visit, IMC Salt, Inc. operated at this site.

The company warehoused and distributed packaged salt. According to company officials, IMC started operations at the site in 1995. Company officials were not aware of vermiculite ore being handled at this facility. EPA did not find any records indicating that Koos had operated at this site before 1995. On the basis of this information, EPA determined no further action was needed.[19]

Former Koos Inc. exfoliation facility, asbestos, & vermiculite

According to an EPA database compiled from W.R. Grace shipping invoices, 1,995 tons of vermiculite ore from the Libby mine were shipped to this site between April 1969 and March 1982.

In addition, reports published by the U.S. Geological Survey in 1975, 1980, 1985, and 1990 indicated that this facility had been a vermiculite exfoliation plant. The site was about 10 acres and was bounded to the north by a street, to the east by railroad tracks, and to the west and south by businesses and residences. At the time of EPA's site visit, IMC Salt, Inc. was operating at the site. The site consisted of an office building, a warehouse and production area, a bulk storage building, and a maintenance shop.

According to IMC officials, IMC Vigaro purchased Koos, Inc. in 1995 and all exfoliation equipment was sold at that time. In 1998, IMC Salt, Inc. began salt packaging and warehousing operations at the site. From 1960 until 1995, Koos had exfoliated vermiculite at the facility and sold vermiculite wholesale. Exfoliated vermiculite was sold for use in fertilizer and in fire proof doors. Some of the exfoliated vermiculite waste had been placed in a local landfill.

An IMC official said Koos purchased vermiculite ore from American Vermiculite (a South African mine) and from W.R. Grace, but, to their knowledge, none of the ore came from the Libby mine. The ore was shipped to the facility by truck and rail and the exfoliation process was performed indoors. EPA did not see any evidence of vermiculite on the site.

On April 3, 2001, EPA collected five soil samples at the site and analyzed them using polarized light microscopy (PLM). None of the samples contained detectable levels of asbestos. On the basis of this information, EPA decided no further action was needed.[20]

Therefore, while the "safe answer" is to spend your money testing your insulation, and given only the information in your brief question, we caution that as we report in detail in the article above, even if your insulation is a vermiculite product (you did not say that it was), a bulk test can give a false negative result. Therefore the EPA and other experts advise that consumers assume that their vermiculite contains asbestos and follow EPA's advice to leave the material alone, undisturbed.

Question: What are the chances that vermiculite in our home came from the Libby Mine?

I have a house in Massachusetts that was constructed circa 1770. Local lore has it that there was an attic fire circa 1890. The wood work and plaster indicate that the attic was "finished" circa 1900. Some floor boards are missing, the floorboards are 1" hard pine, T&G. They also indicate late 19th, early 20th century.

The floorboards were removed in the 1950's for electrical wiring (I am certain vermiculite was not added at that time). I can see about 1 1/2 inches of vermiculite between the joists.

I have spoken with a local resident who grew up in the house in the 1940's, when it did not have electricity. He tells me that heat was by way of a hot air furnace in the cellar which released heat through a large grate in the first floor. This also indicates late 19th century. I would assume that was when any attic insulation was added.

So,my question is. given the era what is the likelihood that the vermiculite came from the Libby mine which contained the asbestos? - Ralph Donaldson 5/5/12

Reply:

Ralph,

Considering the very wide-spread use of Zonolite as a retrofit building insulation product, it is certainly possible that it was used in your home. Zonolite, which was found to contain tremolite asbestos, was produced in very large quantities, reaching 150,000 tons per year by 1950, and the plant continued to operate until 1990. There are other vermiculite mines that do not contain asbestos in their product and that continue to operate today.

It would be a mistake to presume that the Libby Montana Zonolite vermiculite mine source was the only source of asbestos containing products, including insulation, found in homes, as asbestos was used in a very wide range of building and in-home products and continues to appear in some products today. And it might be an error to presume this is the most serious hazard in a home as well.

In our article above we report in detail on the occurrence of asbestos in Zonolite Attic Insulation (ZAI) produced by the Zonolite Company and by its successor owner- W.R. Grace Corporation between 1923 and 1990.

Watch out: It might be useful to have your vermiculite insulation tested. If the result shows Tremolite asbestos (vermiculite mined at Libby Montana had a 10% Tremolite asbestos content) that probably points to the Libby vermiculite mine. But the US EPA warns that bulk testing of vermiculite for asbestos content can sometimes lead to a false negative finding (failing to detect asbestos even though it is present). That's a reason that the US EPA warned that people should err on the side of caution, assuming that it is asbestos-contaminated.

We also are researching the question of whether or not one can report a contents profile that would let one assay a vermiculite sample and guess at its source - as can be done very accurately with roofing slates. We will add that information here.

Question: Insulation in a 1969 house looks like white and gray furry stuff - is this vermiculite or asbestos?

I am buying a house that was build in 1969. I have not tested the insulation yet (I will). However, it doesn't looks like any of the above pictures. It looks like white and gray and furry. Are there still chance for the insulation to contain vermiculite or asbestos? - Will 7/12/2012

Reply:

Will,

For help in identifying the type of insulation in your home, see our INSULATION IDENTIFICATION GUIDE.

From your description you may be looking at Mineral Wool - Rock Wool Insulation.

Question: was asbestos-contaminated vermiculite imported into the U.K.?

Are you aware if any of this contaminated vermiculite was imported to the UK? Thank you. - Laurence 9/15/2012

Reply:

Sorry Laurence, no I don't know.

Typically, because of price competition and the importance of shipping costs, insulation products are produced and shipped from locations a bit closer to their point of use.

Question: where can I have a sample of vermiculite insulation to have it tested?

I recently purchased a house from HUD. I had my home inspected and found out there is exposed vermiculite in the basement that has fallen to the floor and is now been tracked around. Where can I take a sample of this insulation to have it tested ? - Tim 9/16/2012

Reply: Where to Find a Certified or Accredited Asbestos Testing Laboratory

Tim, you can use any test laboratory certified for asbestos testing. Both the US EPA and many U.S. states or Canadian provinces maintain lists of currently-approved asbestos testing labs.

Most state and provincial governments regulate and certify asbestos testing laboratories, and we recommend that where there are health, legal, or cost concerns, you should only use a certified and competent asbestos testing laboratory to examine material samples for asbestos content.

We give a list of several ways to find a certified asbestos test lab at ASBESTOS TEST LABS.

Question: worried sick after our home inspector tested our "vermiculite insulation" for asbestos - lab said it was cellulose

I recently bought a 1940s house which upon inspection was suspected to have vermiculita in a small area of the attic. The home inspector got it tested and it came back composed of cellulose and non fibrous materials, no asbestos. fast forward a few months we are now having our batting insulation replaced and the guys doing the work tell us its vermiculite.

What do we go by? we also had our contractor tell us that its not vermiculite...im worried sick that now that the batting insulation is being removed, asbestos fibers might flying all over our house! - Worried sick., 10/5/2012

Reply: cellulose is not vermiculite and is not asbestos; but one insulation sample may not represent all building insulation in the structure

Worried:

You might be best off trying to not be worried sick, as that itself may be an immediate health hazard and also invites opportunists who may price-gouge you when they see that you're terrified. Scared means costly.

Provided your home inspector used a qualified forensic or asbestos test lab (see Where to Find a Certified or Accredited Asbestos Testing Laboratory),

I'd trust their lab result for the insulation sample that was actually tested.

I am a little surprised that your home inspector could not himself tell the very obvious difference between cellulose building insulation and vermiculite insulation. They are not at all visually similar. Why did he test cellulose (Cellulose loose fill insulation - basically paper) for asbestos? Did he charge you a profit beyond the actual lab fee for that test?

I am not surprised that workers may have found vermiculite insulation in a 1940's house; Vermiculite was widely used as a pour-in insulation retrofit and often a 1940's home was originally built with little or no insulation to start with. In the 1970's many of us (including myself) added various insulation products, including vermiculite, in those homes.

By taking a look at the photographs in this article, even a child should be able to see the difference between vermiculite and other building insulation products.

Our photo above shows a typical blown-in cellulose insulation installation. If indeed your workers are correct and vermiculite is in place, you should

• Stop any work on the building that is or is likely to disturb the material and then
• Follow the advice at Protect Your Family from Asbestos-Contaminated Vermiculite Insulation
• If someone has already made a dusty mess in the home, extra cleaning measures such as damp-wiping and HEPA vacuuming are probably in order, asbestos-containing-vermiculite or not.

Question: did Vermiculite Insulation sold in the U.K. (Ireland in this case) contain asbestos?

I hope you can help me with a query I have. [Paraphrasing at reader request]: there was a vermiculite spill in my home in Ireland. How do I make sure that the home has not been contaminated with asbestos?

Reply: Dust sampling theory: usefulness & definitions of "old dust" and "recent dust" in buildings & where these are found

In an effort to be more clear about dust sampling theory I have expanded the descriptions of old dust, recent dust, where such samples are usually found, and why one would collect them for analysis - that discussion is now found at

DUST SAMPLE TYPES

In short, if you were worried that an original vermiculite spill had not been adequately cleaned, *or* if you wanted to know if the original vermiculite spill included asbestos, you might want to collect both a recent-dust sample and an old dust sample for comparison.

If, however, the cleanup was professionally conducted and post-cleanup testing was already performed properly, and if those steps indicated no problem remaining, in my *opinion* further testing would not be justified unless a new reason for further investigation is apparent.

Examples of such reasons are at MOLD / ENVIRONMENTAL EXPERT, HIRE ? 

and also at MOLD TEST REASONS.

Reader follow-up:

The vermiculite spill was not professionally cleaned, and was swept and vacuumed with a standard household vacuum cleaner by the plumber before I ever knew what vermiculite was

Reply:

Thanks for the follow-up; Ordinary vacuuming actually increases the level of fine particulates; HEPA vacuuming would have been in order if we thought that asbestos was present, along with damp wiping of horizontal surfaces.

Most likely, from your case history, you're ok. If you want to get a settled-dust sample analyzed just send it to a certified asbestos testing laboratory and allow them to choose their method of analysis; typically the lab uses polarized light microscopy following the Walter McCrone procedure.

Some asbestos test labs may also make use of other methods such as SEM; any certified lab will use appropriate asbestos identification procedures - as an amateur I would not second guess the lab ty telling them what to do, just make sure the sample is collected and question posed following their requrested procedure.

...

Continue reading at VERMICULITE INSULATION INCIDENTAL EXPOSURE HAZARDS ? - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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