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j *low <br /> . t <br /> EA ENGINEERING, Western Regional Operations <br /> 41 rcle <br /> SCIENCE, AND Lafayette. <br /> eCate lifornia ornia 94549 <br /> TECHNOLOGY, INC. (415)283-7077 <br /> 16 September 1987 <br /> Richard Reed <br /> State of California <br /> Contractors License Board <br /> 3132 Bradshaw Road <br /> Sacramento, California <br /> Dear Mr. Reed: <br /> I am writing to request your opinion concerning the requirements <br /> for a contractor ' s license to perform a soil vapor survey. <br /> EA Engineering, Science, and Technology, Inc. ( EA) , an environ- <br /> mental consulting firm, has conducted more than 200 of these <br /> survey' s nationwide and more than 50 in the state of California. <br /> These investigations have been conducted in the presence of , and <br /> with the concurrence of numerous California cities, county health <br /> departments, and regional water quality control boards. Without <br /> exception, never outside of San Joaquin County has EA, or to EA' s <br /> knowledge any other consultant conducting soil vapor surveys been <br /> required to possess a contractor ' s license. As you are aware, <br /> the San Joaquin Local Health District is requiring that in order <br /> to conduct a soil vapor survey a consultant must have a C-57 well <br /> drillers license. <br /> In the process of conducting a soil vapor survey EA hand drives <br /> 5/8-inch hollow steel probes into the soil to collect soil gas or <br /> vapor samples. These probes are typically driven to depths of 3 <br /> to 5 feet, at times we have driven the probes to 12 feet. The <br /> probes are never driven into ground water as this would prevent <br /> collection of a soil vapor sample. The probes are immediately <br /> removed after the sample is extracted. We have never left a <br /> probe in place. The samples are analyzed in the field using a <br /> gas chromatograph. The primary emphasis of the process is <br /> collection and analysis of soil vapor. The process is <br /> essentially the same as used by natural gas pipeline owners to <br /> test for gas leaks. <br /> On developed sites with pavement a 1 -inch pilot hole is drilled <br /> through the pavement ( 6-8 inches deep ) using a small hammer drill <br /> and the probe driven in that hole. On undeveloped sites the <br /> probe is simply driven from the ground surface. The sampling <br /> process typically takes 5-15 minutes, after which the probe is <br /> extracted from the ground. No probe has ever been left for more <br /> than one hour . On paved sites the hole is patched with Portland <br /> BALTIMORE 0 CHICAGO 0 CINCINNATI ❑ LINCOLN 0 NEW YORK 0 SAN FRANCISCO <br />