revised June 16, 2003

By Bruce Schundler


On May 21, 2003, the Environmental Protection Agency issued its report: "A Pilot Study to Estimate Asbestos Exposure form Vermiculite Attic Insulation" (66 pages). At the same time, EPA issued a brochure entitled: "Current Best Practices for Vermiculite Attic Insulation" (2 pages).

Hopefully before panicking, becoming too concerned, or hiring professional consultants, homeowners will read the full EPA report, consider the source, and put the report and warnings into perspective---and then relax!

To be sure, if one reads the full study, there seems to be no scientific basis for the kind of conclusions and recommendations included in EPA's two-page consumer brochure. And similar to the previous USEPA study (2000) on Garden Products Containing Vermiculite, the current study has a number of technical errors, and is fraught with scientific limitations, organizational bias, and simple mistakes.

What also is interesting is comparing this study and the EPA's response to asbestos contamination in Manhattan after the World Trade Center disaster. In the vermiculite EPA study, the agency resorted to its previous tendency to promote "zero-tolerance" towards asbestos; and yet, after the World Trade Center disaster the EPA took an entirely different approach.

"Faced with a public health scare that could have sent thousands in Manhattan fleeing the city or jamming hospitals, the EPA decided to cough up the truth about asbestos. Its officials bent over backward to get out the message that asbestos was harmful only if breathed at high levels and over sustained periods of time. When reporters pointed out that some of the tests had exceeded the EPA's safety levels, the agency hurried to explain that this was a "stringent standard based on long-term exposure" and repeated that the public was not at any real risk. (Quoted from article written by Kimberly A. Strassel writing for the Wall Street Journal, October 19, 2001 see The EPA Comes Clean on Asbestos by Kimberley A. Strassel (Wall Street Journal).)"

The EPA's Report on Attic Insulation and Vermiculite:

Knowing their first report had been severely criticized within the scientific community, EPA and its subcontractor, Versar, Inc, tried to make a few disclaimers on the very first page of the report:

  1. "There are uncertainties associated with the exposure estimates based on the data from this study and the frequencies and durations used in this assessment." (Translation: The EPA does not know, or cannot calculate how often and for what periods of time a person would need to be exposed to vermiculite to be at risk for anything.)
  2. "There are no survey data indicating the number of times residents install wiring or disturb insulation in their attics." (Translation: The EPA knows most people spend virtually no time in their attics, and few people spend much time doing home repairs or home wiring in their attics. And risk assessments become totally meaningless, if not impossible, if there is virtually no time period of exposure to virtually no detectable fibers.)
  3. "Cancer risks are not estimated in this report because there is great uncertainty associated with primarily basing cancer risk estimates on a limited sampling of vermiculite products that contain only trace amounts of asbestos in the simulations." (Translation: The EPA contractor is not able to or willing to make any kind of risk assessments based on the data found in the report.)

Some More Background Information:

There are many vermiculite mines in the world, and current operating mines being used today have no asbestos contamination. Historically the two largest mines had been the Palabora, South Africa mine and the Libby, Montana mine. Like all the other vermiculite mines being used today, Palabora has never had an asbestos problem. Unfortunately, the Libby, Montana mine had been used since the late 1920's, it was second only to the Palabora mine in size, and it was unique among vermiculite mines in that the vermiculite developed next to and commingled with diopside that eventually turned into a harmful form of asbestos.

The Libby, Montana mine was closed in 1990, but vermiculite from this mine has been used to insulate many homes and buildings throughout the years of its operation. (Vermiculite had been a very prominent and popular form of home insulation until the invention and marketing of fiberglass and rock wool.)

To date, the only people who have had health problems from this particular Libby, Montana vermiculite have been:

  • mine workers and people living next to the mine and the vermiculite mining operation in Libby, and
  • a very small number of processing plant workers who worked with the crude ore every day for years and years.

Among people who were exposed to or worked with only the expanded, processed vermiculite, we don't know of any one who has become sick or developed asbestosis or mesothelioma from exposure to Libby, Montana vermiculite. This may be because if any fibers are found in the expanded Libby material, the levels of asbestos are very, very low. And most people simply are not exposed to expanded vermiculite enough to ever develop problems at these levels.

To put EPA's results into perspective, it should be noted that asbestos has been in and around homes for years. It was used in virtually all home-heating appliances like toasters, ovens, stoves, irons, hair driers, and floor heaters. Electrical cords and plugs for these appliances often had "bundles" of pure asbestos fibers in and around them. Asbestos also was used in floor tiles, cement siding, roofing shingles, refractory cements, and many furnaces. And it was used in automobile brakes and clutches. To be sure, it is not the mere presence of asbestos that is potentially dangerous----what can and is dangerous is if people are exposed to very high levels of respirable asbestos fibers over a long period of time.

For instance, according to current OSHA standards, a worker working 8 hours/day, five days a week, for 52 weeks a year can be exposed constantly to 0.1 f/cc (fibers/cubic centimeter) because OSHA considers this level to be acceptable and because there is no scientific data available that demonstrates a health risk at this level.

If a worker has to do work in which there will be greater exposure, then there is an "excursion limit." The excursion limits mean a worker can work for up to 30 minute to up to 1.0 f/cc and still be working in conditions that OSHA considers safe.

There are many materials in and around our homes that can become unsafe if we are exposed to too much. People living in the northeast have radon gas in many basements. As long as families don't live in basements, close all their doors and windows and never leave their basements, most homes are considered safe, and remediation is only necessary when there are excessive amounts of radon gas present. In fact, the same could be said for attics where very little time is usually spent!

"The presence of a small proportion of tremolite-actinolite in a building material, even if it is present as the asbestos variety, does not necessarily mean that the material is hazardous. If that were the criterion for definition of a hazardous material, we would have to say that sand, concrete and cement are all extremely hazardous because they contain high concentrations of crystalline silica. We don't don dust masks, for example, when we walk on a sandy beach or enter a building with concrete walls, and children are still allowed to play in sand boxes without any concern that any one of them will contract silicosis as a result of these activities." (Letter to the Editor, Progressive Builder Inc, October 9, 1987 from Dr. Eric Chatfield.)

Because of its usage in so many products throughout many years, asbestos fibers are present in almost all older homes---and yet, how many people have died as a result?

Needless to say, we feel the most recent EPA study on Attic Insulation should be read in its entirely by homeowners and reporters, and then put into perspective.

Outline of the EPA Report:

The EPA studied only 10 samples of vermiculite, and 6 homes insulated with vermiculite:

The 10 samples came from:

  • 5 products from four different cities (three of these were Zonolite brand)
  • 3 samples of vermiculite from an old storage area from the Seattle Public Utility (all of these were W.R. Grace's Zonolite and they are presumed to be from the closed Libby mine),
  • and 2 partially used bags of vermiculite attic insulation that were obtained from two Washington state residents (these bags were old Zonolite bags and it was presumed that this material also came from Libby, Montana too).

In addition, EPA checked 5 attics in occupied homes in Vermont and 1 unoccupied home in Vermont.

EPA also tried to simulate activities with vermiculite such as installing vermiculite, disturbing it, removing it, etc.

In EPA's report, it describes how:

  • No asbestos fibers were found in any of the five vermiculite products purchased. (Note: no fibers by both the PLM method and more definitive TEM method)

    (Translation: The PCM analysis not only counts asbestos fibers, but also non-asbestos fibers. It cannot distinguish between asbestos fifers and non-asbestos fibers. After fibers are detected by the PCM method, a TEM analysis is conducted to determine if the fibers are Asbestiform or not. As such, sometimes there are fibers found in vermiculite that are not asbestos!)

    The vermiculite currently on the market and vermiculite processed from mines other than Libby, Montana do not have asbestos problems, and this was verified once again by this EPA study!)

  • In the other five older bags of Libby, Montana vermiculite, the asbestos content was found to be <1 % by PLM methods, and either ND (non detect) or <0.1 % by the TEM method.

    (Translation: The amount of Asbestiform material was found to be less than the Limits of Quantification for each of the test methods.)

  • In the six homes that were checked, the TEM method of analysis found ND (non detect) in 11 of the 29 samples taken, and < 0.1 % in 7 of the others.

Note: These test were done to identify whether there were any fibers of any kind in the vermiculite, and whether any of the fibers found could be identified as asbestos.

Actually what is more important for homeowners is a very different issue: how many fibers are present in the air if and when Libby, Montana vermiculite is present in an attic. And are these fibers small enough to get into lungs and cause problems?

To be sure, the presence of crystalline silica in Portland cement in our homes isn't nearly as important as whether the crystalline silica is present in the air we breath and in particle sizes that can harm us. And asbestos insulation in many of our older stoves and ovens doesn't hurt us if it stays there and doesn't get into the air we breath.

The EPA conducted a number of tests in addition to the bulk sampling. They were trying to find out if asbestos from Libby, Montana gets into homes and attics, and whether asbestos would become airborne if disturbed, moved, or installed.

The important results:

(Page 23) After a complex "simulation" with material known to have come from Libby, the results were summarized:

  • "During the three days in which fibers were allowed to settle, no asbestos fibers were detected by TEM in these air samples. No fibers were detected by either PCM or TEM in the air samples collected on the third day of fiber settling stimulation."
  • "Before the initiation of the residential activity simulation asbestos fibers were not detected in the air samples, suggested that asbestos fibers had settled."
  • "During the simulation of residential activities (i.e. moving the vermiculite insulation to install wiring, moving boxes, etc) airborne asbestos fibers were detected. The highest asbestos level of 0.43 fibers per cc was detected in one of the personal air samples. (Reminder: this is less than half of the OSHA excursion levels.)

Or, consider EPA's "Exposure Scenarios":

  • Living in a house where vermiculite was installed once in a lifetime....the asbestos detected ranged from 0.0078f/cc to 0.011 f/cc (e.g. almost the levels known as the "ambient levels of asbestos in any home."
  • Living in a house where dry vermiculite insulation is removed once....the asbestos concentrations detected ranged from 0.011 to 0.089 f/cc, and in another house from 0.0026 to 0.014 f/cc.
  • Living in a house where there was minimal vermiculite attic insulation disturbance (moving boxes four times a year) fibers were detected in the simulated living space during or after the simulations.
  • Background exposure (living in a house with vermiculite insulation ) ....."No fibers were detected in the living areas of the occupied houses containing vermiculite attic insulation visited in Vermont during Phase 1."

Some Unscientific Postscripts or Final Observations:

  • Only a very few fibers were ever found by the EPA, and only when the EPA really "worked" at stirring up the vermiculite, and only when the vermiculite being tested was Libby, Montana material.
  • Even in these cases, fibers were not found in the ambient air before the vermiculite was handled or moved.
  • In other word, vermiculite insulation, even when Libby, Montana vermiculite is present, does not seem to pose a significant health risk, and homeowners would be advised to just leave it alone (This is what EPA has been advising homeowners anyway.)

Other reports and information on Vermiculite:

Or, call or contact us at:

The Schundler Company P.O. Box 513 Metuchen, New Jersey 08840
(ph)732-287-2244 (fax) 732-287-4185

Back to Vermiculite Institute Links, or

Back to Our Main Page