Vermiculite insulation exposure levels in residential buildings:

What are 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

. But those researchers have extrapolated from that work to offer observations about the probability that amphibole-asbestos in Zonolite insulation is hazarous to occupants of normal residential structures where vermiculite was used as attic or wall insulation.

This article series explains how to recognize vermiculite building insulation that may contain asbestos fibers. This article series assists building buyers, owners or inspectors who need to identify asbestos materials (or probable-asbestos) in buildings by simple visual inspection. We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products to permit identification of definite, probable, or possible asbestos materials in buildings.

Hazards from Incidental Exposure to Vermiculite: Research & Opinion

Reader Question: accidental exposure of children to vermiculite insulation that might contain asbestos

We were researching when we found your website. We're currently remodeling our bathroom and found vermiculite insulation and the balsam wool insulation. We had no idea what either was and my 5 year old daughter and 2 year old sun were in the bathroom with me playing in the vermiculite insulation.

My wife and I feel like horrible parents after reading all about vermiculite insulation. She saw that you guys do testing but we read it can be expensive and the results can be skewed? we're not sure what to do or who to trust.

I feel pretty good about the balsam wool insulation but your site seemed very knowledgeable and we read that we need to arrange something before sending out to your lab.
Thanks for any information

Reply:

Sorry, I'm not able to perform testing of your insulation. To assure readers of our impartiality, in general we don't offer goods or services for sale.

I'm not sure you need to test as I elaborate below, but if you want to proceed you can use any certified asbestos test lab,

ASBESTOS TESTING LAB LIST will help you choose one.

Even if you test a sample and confirm that it contains asbestos I'm doubtful that that will change what you do about the loose insulation now. In any event it'd make sense to handle the material as if it contained asbestos - fine particulates are respiratory irritants regardless. Clean up using a HEPA vacuum cleaner, damp mopping, etc.

Don't berate yourselves. A limited, short term exposure to dust is unlikely to produce measurable effects. The people who developed asbestosis were generally workers in construction or in factories where the air was thick with material. I'm not cavalier about your kids, I've had kids, grand kids and so on myself but that's my OPINION, supported by some of the citations below such as Hughes (1994) and Vinikoor (2010)*.

Wash everybody and stay out of the dust. If you see the kids coughing consult with their pediatrician for follow-up.

Take a look at theReferences or Citations below for more details from the US EPA. Don't panic - doing so is likely to result in gouging by a clean-up contractor.

Watch out: see WARNINGS BEFORE REMOVING VERMICULITE INSULATION

References on asbestos hazards from incidental or other vermiculite exposure

Some of these references on asbestos hazards from vermiculite exposure can be scary if you don't read them carefully. Noting the emphasis on the unusual nature of some of these cases means that non-occupational exposure to asbestos-containing vermiculite insulation has only rarely been linked to disease.

From Radon data & research we know that smokers have an 80 times higher risk of lung cancer from breathing in small harmful particles to which radon or its daughters were attached. Smoking is a risk multiplier that it seems to me probably pertained to asbestos hazards as well. Unless your kids are smokers, one might infer that their risk is further reduced.

• Antao, Vinicius C., Theodore C. Larson, and D. Kevin Horton. "Libby vermiculite exposure and risk of developing asbestos-related lung and pleural diseases." Current opinion in pulmonary medicine 18, no. 2 (2012): 161-167.
• ATSDR, EXPOSURE TO ASBESTOS-CONTAINING VERMICULITE FROM LIBBY, MONTANA, AT 28 PROCESSING SITES IN THE UNITED STATES [PDF] (2008) U.S. Department of Health and Human Services Agency for Toxic Substances and Disease Registry Division of Health Assessment and Consultation, Tel: 800-CDC-INFO (800-232-4636) E-mail: cdcinfo@cdc.gov Website: http://www.atsdr.cdc.gov.
  Excerpts:
  
  Conclusion (1) ATSDR identified these three groups of people who experienced significant exposure to asbestos (specifically Libby amphiboles) associated with facilities that exfoliated vermiculite:
  - Former employees,
  - Household contacts of former employees, and
  - Some community members, particularly children, who had frequent, direct contact with VC or waste rock from these facilities.
  
  Conclusion (2) The findings from evaluations of 27 exfoliation facilities3 (most of which operated in the past) suggest that residual asbestos in the form of Libby amphiboles may be present in indoor settled dust at many of the other 78 sites identified as former exfoliation facilities. Many of these facilities currently are being used for other, non-exfoliation commercial or industrial operations.
  
  Conclusion (3) The findings from evaluations of 27 exfoliation facilities (most of which operated in the past) suggest that residual asbestos in the form of Libby amphiboles may be present in exterior soil at many of the other 78 sites identified as former exfoliation facilities. Many of these facilities currently are being used for other, non-exfoliation commercial or industrial operations.
• Bandli, Bryan R., and Mickey E. Gunter. "A review of scientific literature examining the mining history, geology, mineralogy, and amphibole asbestos health effects of the Rainy Creek igneous complex, Libby, Montana, USA."Inhalation toxicology 18, no. 12 (2006): 949-962.
• Bourdès, Valérie, Paolo Boffetta, and Paola Pisani. "Environmental exposure to asbestos and risk of pleural mesothelioma: review and meta-analysis."European journal of epidemiology 16, no. 5 (2000): 411-417.
  Abstract:
  
  A number of epidemiological studies have addressed the risk of pleural mesothelioma from environmental (household and neighborhood) exposure to asbestos, but no overall risk estimate is available. We reviewed the epidemiological studies on risk of pleural mesothelioma and household or neighborhood exposure to asbestos.
  
  We identified eight relevant studies; most were conducted in populations with relatively high exposure levels. We combined the risk estimates in a meta-analysis based on the random-effects model.
  
  The relative risks (RRs) of pleural mesothelioma for household exposure ranged between 4.0 and 23.7, and the summary risk estimate was 8.1 (95% confidence interval [CI]: 5.3–12). For neighborhood exposure, RRs ranged between 5.1 and 9.3 (with a single RR of 0.2) and the summary estimate was 7.0 (95% CI: 4.7–11).
  
  This review suggests a substantial increase in risk of pleural mesothelioma following high environmental exposure to asbestos; however, the available data are insufficient to estimate the magnitude of the excess risk at the levels of environmental exposure commonly encountered by the general population in industrial countries. [Bold by Editors]
• Case, B. W., J. L. Abraham, G. D. P. F. Meeker, F. D. Pooley, and K. E. Pinkerton. "Applying definitions of “asbestos” to environmental and “low-dose” exposure levels and health effects, particularly malignant mesothelioma." Journal of Toxicology and Environmental Health, Part B 14, no. 1-4 (2011): 3-39.
• Gunter, Mickey E. "An overview of the past, present, and future concerns surrounding the asbestos content of vermiculite ore from Libby, Montana." In2004 Denver Annual Meeting. 2004.
  
  As we meet this November, we mark five years since a small town in northwestern Montana was placed in the national spotlight as the newest “asbestos problem” in the USA. The problem originates from the asbestos content of the vermiculite ore mined near Libby. Unfortunately, the geological conditions that formed this world-class vermiculite deposit by alteration of existing biotite in an ultramafic intrusion also altered the pyroxenes to amphibole and amphibole-asbestos.
  
  The vermiculite mine began production in the early 1920’s and ceased operation in 1990. During that time, it was one of the world’s largest vermiculite mines.
  
  After mining, the vermiculite ore was expanded by rapid heating. This expanded product has several industrial uses, most commonly in gardening products; however, the commercial product produced from the Libby ore, termed Zonolite, was also used as home attic insulation.
  
  The asbestos content of this product and the vermiculite ore have been measured as high as a few percent, but more often is considerably less. Interestingly, the majority of the amphibole-asbestos at the former mine are the non-regulated amphibole species winchite and richterite. [Bold by Editors]
  
  The major health concern was initially focused on the few hundred miners. Studies in the mid-1980’s showed their death rates were approximately 2.5 times higher than expected for asbestosis, mesothleioma, and lung cancer. Five years ago, concern shifted to the few thousand residents of the community and most recently to homeowners across the USA who have Zonolite as an attic insulation.
  
  The popular media has estimated as many as 35 million homes in the USA may contain Zonolite; however, common-sense dictates these estimates are far too high because there are fewer than 65 million homes in the USA.
  
  Regardless, it is clear that individuals with occupational exposure in the duster operations at the mine suffered increase asbestos-related deaths. The health risk becomes less clear for non-occupational exposure of the Libby residents.
  
  Finally, it would seem unlikely that Zonolite attic insulation would pose a significant health risk to a homeowner because exposure levels decrease by orders of magnitude between the miners and the homeowners. [Bold by Editors]
• Hughes, JANET M. "Human evidence: lung cancer mortality risk from chrysotile exposure." The Annals of occupational hygiene 38, no. 4 (1994): 555-60. - Excerpt:
  ... a number of studies have demonstrated evidence that lung cancer risk is not associated with years exposed to low exposure
• Libby, Montana, Where Asbestos Can Be Found, and What To Do If You Have. "Protocol to Confirm Asbestos-Related Abnormalities." http://www.atsdr.cdc.gov/Asbestos/sites/libby_montana/doc_abnorm.html
• Egilman, David, Wes Wallace, and Candace Hom. "Corporate corruption of medical literature: Asbestos studies concealed by WR Grace & Co.∗."Accountability in research 6, no. 1-2 (1998): 127-147.
• Erwin, Daniel, "Libby Vermiculite Insulation: A Guide for Homeowners, Homebuyers, Home Inspectors, Real Estate Professionals, Residential Contractors and Tradespersons [Kindle Edition]", [sold via Amazon.com] (2014) ASIN: B00LNEO4PO
• Erwin, Daniel, "Libby Vermiculite Insulation: A Guide for Environmental Professionals [Kindle Edition]", [at Amazon.com] (2014), ASIN: B00LCIFNLU
• Lowers, Heather A., Alfred L. Bush, Gregory P. Meeker, Geoffrey S. Plumlee, Isabelle K. Brownfield, and Stephen J. Sutley. Reconnaissance Study of the Geology of US Vermiculite Deposits: Are Asbestos Minerals Common Constituents?. US Department of the Interior, US Geological Survey, 2002.
• McDonald, J. Corbett, and Alison McDonald. "Mesothelioma and asbestos exposure." In Malignant mesothelioma, pp. 267-292. Springer New York, 2005.
• Ostroff, Rachel M., Michael R. Mehan, Alex Stewart, Deborah Ayers, Edward N. Brody, Stephen A. Williams, Stephen Levin et al. "Early detection of malignant pleural mesothelioma in asbestos-exposed individuals with a noninvasive proteomics-based surveillance tool." PloS one 7, no. 10 (2012): e46091.
  Abstract:
  
  An unusual case of pleuroparenchymal lung disease caused by the inhalation of vermiculite dust, presumably containing asbestos fibers is described. The uniqueness of the case lies in the very indirect nature of exposure – the wife of a factory owner, rather than a worker exposed to asbestos, whose factory manufactured vermiculite.
  
  The present case illustrates the importance of taking careful occupational histories of all household members when presented with a patient whose chest radiograph exhibits features consistent with asbestos exposure.
  
  Asbestos-associated lung disease may occur without direct occupational exposure to asbestos, such as in the spouses of exposed workers. It is suspected that the disease is caused by the direct inhalation of asbestos fibers contained in work clothes. We describe the case of a woman who developed lung disease from an even less direct exposure.
  
  Her husband owned a factory manufacturing vermiculite, which may contain an asbestiform amphibole mineral.
  Keywords: Asbestosis, Pleural disease, Second-hand exposure, Vermiculite
• Reid, Alison, Geoffrey Berry, Nicholas de Klerk, Janice Hansen, Jane Heyworth, Gina Ambrosini, Lin Fritschi, Nola Olsen, Enzo Merler, and AW Bill Musk. "Age and sex differences in malignant mesothelioma after residential exposure to blue asbestos (crocidolite)." CHEST Journal 131, no. 2 (2007): 376-382.
  Excerpt:
  Blue asbestos was mined and milled at Wittenoom, Western Australia, from 1943 until 1966. Various public records were used to establish a cohort of residents of the nearby township. Mine tailings were distributed throughout the town.
• Samet, Jonathan M., and John D. Spengler. "Indoor environments and health: moving into the 21st century." American Journal of Public Health 93, no. 9 (2003): 1489-1493.
• Sanchez, Matthew S., and Mickey E. Gunter. "Quantification of amphibole content in expanded vermiculite products from Libby, Montana USA using powder X-ray diffraction." American Mineralogist 91, no. 8/9 (2006): 1448.
• Vinikoor, Lisa C., Theodore C. Larson, Thomas F. Bateson, and Linda Birnbaum. "Exposure to asbestos-containing vermiculite ore and respiratory symptoms among individuals who were children while the mine was active in Libby, Montana." Environmental health perspectives 118, no. 7 (2010): 1033.
• Wylie, Ann G., and Jennifer R. Verkouteren. "Amphibole asbestos from Libby, Montana: Aspects of nomenclature." American Mineralogist 85, no. 10 (2000): 1540-1542.
  Excerpt:
  These cases are in non-occupationally exposed people, appearing to have resulted from exposure to contamination of the community, the surrounding forested area, and areas in proximity to the Kootenai river and railroad tracks used to haul vermiculite. ​ These exposures are considered to be of a low degree of magnitude, but are similar to those in Western Australia's crocidolite mine at Wittenoom Gorge. An epidemic of mesothelioma can likely be expected from this type of asbestos contamination over the next 20 plus years. Am. J. Ind. Med. 51:877-880, 2008. © 2008 Wiley-Liss, Inc
• Whitehouse, Alan C., C. Bradford Black, Mark S. Heppe, John Ruckdeschel, and Stephen M. Levin. "Environmental exposure to Libby asbestos and mesotheliomas." American journal of industrial medicine 51, no. 11 (2008): 877-880.

What should I do if I have vermiculite insulation in my building ?

Quoting & paraphrasing or elaborating further from the U.S. EPA information on Vermiculite[5]:

You should assume that the vermiculite insulation contains asbestos and it should not be disturbed. Particularly, do not stir up nor spread dust from this product.! Any disturbance could potentially release asbestos fibers into the air. If you absolutely have to go in your attic and it contains vermiculite insulation, you should limit the number of trips you make and shorten the length of those trips in order to help limit your potential exposure.

We and the US EPA recommend that you:

• Leave vermiculite insulation undisturbed in your attic or in your walls.
• Do not store boxes or other items in your attic if it contains vermiculite insulation.
• Do not allow children to play in an attic with vermiculite insulation.
• Do not attempt to remove the vermiculite insulation yourself.
• Hire a professional asbestos contractor if you plan to remodel or conduct renovations that would disturb the vermiculite in your attic or walls to make sure the material is safely handled and/or removed.
• [If substantial costs are involved in handling or removing any building product suspected of containing asbestos, particularly friable asbestos that can easily be spread through a building as airborne dust, you should have the material tested to confirm its asbestos content and in order to understand what special handling may be required. ] - Ed.

For more details about the inspection and detection of concerns with fiberglass building insulation, see:

INSULATION INSPECTION & IMPROVEMENT

and FIBERGLASS HAZARDS .

Our separate websites on Fiberglass building insulation and or series of articles about HVAC duct work defects contain in-depth discussion about possible air quality and health concerns which may be associated with exposure to fiberglass dust.

To compare insulating material R-values of fiberglass in various forms as well as other insulating materials, see

our Table of Properties of Insulating Materials

Also see these U.S. & Canadian Guides to Asbestos-Hazards in Vermiculite Insulation

• Vermiculite: Protect Your Family from Asbestos-Contaminated Vermiculite Insulation, U.S. EPA
• Proteja su familia del aislante de vermiculita contaminado con asbestos, U.S. EPA
• Current Best Practices for Vermiculite Attic Insulation - May 2003, U.S. EPA
• Vermiculite Insulation Containing Amphibole Asbestos - September 2009, Health Canada

How Vermiculite Attic Insulation Becomes Airborne

Any airborne dust particles can be a respiratory irritant, but the hazard level is likely to be increased if the dust contains insect or rodent materials and of course also if it contains asbestos as is present in some vermiculite insulation installations. Particularly where loose fill vermiculite insulation remains exposed in an attic, such as in the attic floor, the following act ivies are likely to cause dust from this product to become airborne.

• Operating a whole house fan or an attic vent fan
• Walking on or near the vermiculite insulation
• Disturbing the vermiculite insulation during building remodeling, renovations, or roofing work
• Storing items on the vermiculite insulation - which risks transporting dust out of the attic into the living space if those items are then brought into the occupied space below

You can reduce these dust risks by installing a plywood floor over the tops of the floor joists (ceiling joists of the rooms below), by installing fiberglass batts on top of the vermiculite, or by spraying an acrylic encapsulant on the exposed surface of the vermiculite in the attic.

Watch out: spray-coating the upper surface of an attic insulation material installed in the floor risks creating a vapor barrier on the wrong side (the cold side) of the structure, trapping moisture and leading to condensation or even mold troubles.

...

Continue reading at WHAT TO DO ABOUT VERMICULITE INSULATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see VERMICULITE INSULATION INCIDENTAL EXPOSURE HAZARD FAQs - questions & answers posted originally at this page.

Or see these

Recommended Articles

• ASBESTOS STYROFOAM PANELS
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• INSULATION IDENTIFICATION GUIDE
• VERMICULITE INSULATION - home
• HOW TO IDENTIFY VERMICULITE INSULATION - separate article
• VERMICULITE HISTORY & PROPERTIES
• WHAT TO DO ABOUT VERMICULITE INSULATION
• ZONOLITE BRAND VERMIULITE INSULATION ZAI & CLAIMS
• MUNN & STEELE VERMICULITE, MICA-FIL, Siscoe Vermiculite Mine
• VERMICULITE INSULATION INCIDENTAL EXPOSURE HAZARDS ?
• VERMICULITE INSULATION INCIDENTAL EXPOSURE HAZARD FAQs

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VERMICULITE INSULATION INCIDENTAL EXPOSURE HAZARDS ? at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to ASBESTOS HAZARDS

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In addition to any citations in the article above, a full list is available on request.

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