Chem Scope, Inc. Client Advisory

Vermiculite Analysis – Asbestos

5/5/05, Supersedes Issue of 5/29/03

This advisory is for clients and potential clients wishing investigations regarding vermiculite.

EPA Hazard Warning:

In May 2003, EPA released information indicating that vermiculite contaminated with traces, less than 1% asbestos is of significant concern. A notice appeared on the EPA web site "National Consumer Awareness Campaign Launched on Vermiculite Insulation Used in Some Attics." In this release EPA states that "… home testing vermiculite in attics is not currently practical. Therefore it is best to assume that the material may contain asbestos and take the appropriate precautions…"

The data supporting EPA’s position is complex and there is disagreement among members of the scientific community. I have summarized the key points below.

Summary of the Analytical Concerns Reported:

1. Two rare forms of asbestos have been reported in Zonolite vermiculite from Libby Montana which are not among the 6 asbestos minerals regulated by federal and state agencies and are not routinely included in lab tests, other than a research method which is described below.

2. Asbestos is not uniformly distributed in vermiculite so that a negative sample result may not be reliable.

3. There is evidence of hazardous airborne asbestos concentrations associated with disturbance of vermiculite with amounts of asbestos less than the current regulated (1%) concentration.

Several methods are available to conduct tests for asbestos:

1. To determine asbestos content of the bulk material:

a. PLM (polarizing light microscopy) EPA Method (# 600/R-93/116). This is the method legally accepted by regulating agencies vs the standard of 1%.

b. TEM (transmission electron microscopy), useful as a confirmatory test.

c. Research Method EPA/600/R-04/004 which uses a combination of PLM and TEM.

PLM is the method upon which regulations for asbestos in building materials are based. EPA has set a standard and regulates building materials with more than 1% asbestos. This is the least costly method, $20-50 per sample.

TEM is more sensitive method which sees smaller fibers although there is no regulated standard based on TEM in bulk materials federally or in the state of Connecticut. Sometimes TEM detects asbestos in samples when PLM does not or the TEM results are much higher. This test costs $50-150/ sample.

The Research method uses water flotation to separate the vermiculite into fractions. PLM is used on one fraction and TEM on the other. The estimated cost is $400-1,000/ sample.

2. To determine background levels of asbestos in air:

a. PCM (phase contrast microscopy (NIOSH Method 7400)

b. PCM plus PLM (OSHA Method ID-160)

c. TEM (transmission electron microscopy) (EPA- AHERA Protocol)

Note: The following are limitations of background air samples:

Air samples may vary from day to day and are only representative of concentrations at the time of sampling.

Background sampling does not usually simulate conditions during which vermiculite is being disturbed.

PCM alone counts all fibers in air and can be compared to state and federal final clearance criterion of 0.01 fiber per cc of air (f/cc) and to the OSHA permissible exposure limit of 0.1 f/cc.

PCM plus PLM counts all fibers except it does not count recognizable non-asbestos fibers and results can be compared to the OSHA permissible exposure limit of 0.1 f/cc.

As above, TEM is more sensitive and can identify very small asbestos fibers. Results can be compared to the clearance criterion of 70 structures per sq. mm (s/mm2).

Justification for Testing Vermiculite

Although a result of none detected or < 1 % by PLM does not assure that the material is "safe", the primary purpose would be to see if the material is regulated under the present EPA, OSHA, DEP and DPH regulations, i.e. > 1% by PLM. Historically, we have found up to 30% asbestos in environmental vermiculite samples by this method. If the material exceeds the 1% level, then specific requirements are triggered if the owner elects to remove or otherwise abate the material.

Our Recommended Minimum Test Program for Initial Screening:

1. A licensed inspector & project monitor should collect the samples using proper safety precautions.

2. PLM analysis of at least 3 samples of each bulk material.

Each sample should be collected through the entire cross section of a vermiculite layer. If the material is in a bag with the manufacturer’s label, you can also consult the manufacturer. If bags are sampled, note any lot number and product information and take samples from top, middle and bottom of bag using a core sampler, then repairing the bag and enclosing in an air-tight plastic bag.

Other Options:

1. Vacuum dust samples tested by PLM.

Select areas where tracking may have occurred, areas with visible dust or other areas judged by the inspector to be of interest.

2. At least one TEM background air sample inside vs one outside air sample at locations determined by the project monitor.

3. If PLM results are negative, the bulk samples can be checked by TEM.

4. Additional bulk, dust or air samples can be taken to improve reliability.

5. TEM dust samples can be taken at the client’s option. Be advised that this test is so sensitive that most buildings show up asbestos in the dust and there is no standard for comparison.

6. In the occupational setting, PCM personal exposure sampling is needed.

7. If the above tests are negative, the Research Method could be used, with the following reservations:

a. The method was specifically developed for one brand of vermiculite and does not necessarily work for all vermiculite brands.

b. The results are for information only. There are no regulated standards based on this method.

Supplementary Information:

1. EPA reports 2-15% tremolite asbestos in Libby, Montana vermiculite ore tailings using the PLM method.

2. EPA has also had many other vermiculite samples tested using both TEM and PLM.

The concentrations found in EPA studies of the actual vermiculite product as sold is much lower than the Libby mine tailings, ranging from none detected to about 2%. Most samples had below 1%. Sometimes the TEM picks up these traces and PLM does not. Sometimes PLM detects asbestos and TEM does not. Part of the problem is that the material is not homogeneous considering the small sample size used.

3. Asbestos has also been added to vermiculite in the range of 10-30% as part of a manufacturing process. These materials are unquestionably regulated and the asbestos is readily detected by routine PLM analysis.

This advisory may be modified without notice in the future as more information is developed. The client is encouraged to visit the EPA web site at EPA.gov to obtain more information and to stay abreast of this issue.