Activity-based asbestos air sampling was done in 2004 for U.S. EPA to assess the public health hazard due to Naturally Occurring Asbestos (NOA) in El Dorado Hills, CA. Asbestos TEM Labs perform custom bulk soil sample preparation and analysis by polarized light microscopy (PLM). In addition,air sample analysis by phase contrast microscopy was performed for EPA to assess the public health hazard from NOA. The results are included in EPA's 2005 "El Dorado Hills Naturally Occurring Asbestos Multimedia Exposure Assessment, El Dorado Hills, California Preliminary Assessment and Site Inspection Report - Interim Final".(here)
Controversy arose after the publication of the report with the 2006 Stone, Sand and Gravel by the RJ Lee Group which criticised many of the EPA's findings stating, in summary, that little or no asbestos was present in El Dorado Hills, and that EPA had erroneously identifed the presence of asbestos (here).
Asbestos TEM Labs President, Mark Bailey PG, was retained by EPA as consulting geologist/mineralogist to respond to the criticisms leveled at the EPA report on El Dorado Hills by the Sand and Gravel Association. While not responsible for the final report, his findings were used as part of the basis for EPA's 2006 report titled "Response to the November 2005 National Stone, Sand & Gravel Association Report Prepared by the R.J. Lee Group, Inc “Evaluation of EPA’s Analytical Data from the El Dorado Hills Asbestos Evaluation Project” (here)
In addition, research was performed, and a report generated by Dr. Greg Meeker of the US Geologlical Survey in his 2006 Report, "Mineralogy and Morphology of Amphiboles Observed in Soils and Rocks in El Dorado Hills, California" (here), which also contributed to EPA's reponse confirming EPA's initial findings. The USGS findings were also consistent with Mr. Bailey's findings in his initial response.
Through it all, Mr. Bailey and Asbestos TEM Labs were involved in various parts of the both EPA's original report and final response.