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• Ms. Sarah Slaughter Page 3 Atwell, LLC November 4, 2010 BULK SAMPLING METHODOLOGY AND FINDINGS Bulk samples were analyzed by Polarized Light Microscopy (PLM) using the United States Environmental Protection Agency USEPA/600/R- 93/116 method. The analysis of samples was conducted by Air Quality Environmental, Inc., 9325 Seminole Blvd., Seminole, Florida (NVLAP Accreditation 200759 -0). There are six minerals grouped into the term "asbestos." Chrysotile, amosite, and crocidolite are the asbestos minerals most commonly found in building materials. ACM is deemed as a material containing more than one percent (1 %) asbestos by weight. Materials found to be asbestos containing are listed below. Exact sample compositions are included in the laboratory reports or chains of custody found in Attachment I. Polarized light microscopy (PLM) is the root method used for the identification of ACM. The USEPA Office of Research and Development (USEPA/ORD) has reviewed data from performance audits of various laboratories performing PLM. The results of that review indicated an unacceptable number of false negatives and positives for visual estimation of materials containing less than 10% asbestos. On the basis of those findings the National Emission Standards Hazardous Air Pollutants (NESHAP) regulations were amended on November 20, 1990 (Federal Register, V.55, N.224). The revisions state that if the analyst detects asbestos in the sample and estimates the amount to be less than 10% by visual estimation, the parties legally responsible (owner or operator) for the building may (1) elect to assume the amount to be greater than 1% and treat the material as ACM or (2) require verification of the amount by point counting. Point counting is a technique used to quantify the amount of asbestos present in a sample on which PLM has already been performed. ECS recommends point counting re- analysis for asbestos values less than 10 %, and where applicable those results are reflected in the report. In instances where client authorization is not received for this reanalysis, PLM visual results indicating a trace or 1% value will be reported as assumed ACM as required by item (1) above. A similar situation exists for matrix bound fibers such as those found in floor tiles, mastics, and asphalt based materials. The inorganic matrix of these bulk samples may interfere with the identification and quantification of asbestos mineral content. These types of samples are generally referred to as Non - organically bound (NOB) materials. Transmission Electron Microscopy (TEM- NOB) is a method that utilizes a combination of special sample preparation techniques and high magnification to more accurately quantify asbestos content. Although additional cost is involved, ECS recommends TEM -NOB analysis under certain circumstances, as a state of the art means of evaluation. A summary of the materials sampled, their locations, and analytical results are presented in Table 1, and the Asbestos Analysis Results, with chain -of -custody, are provided in Attachment 1. CONCLUSIONS AND RECOMMENDATIONS A total of twenty -four (24) samples of suspect ACM were collected of the eight (8) different homogeneous building materials identified. Based on "first positive stop" request on analysis, 24 total analyses were conducted. Analytical results of the samples revealed that none of the homogenous materials sampled contained asbestos in concentrations >1% by PLM analysis. ECS recommends that no response action be taken due to the lack of asbestos containing materials identified at the subject property. However, it should be noted that any areas deemed inaccessible by this report, or any other building materials not identified herein should be treated as asbestos