EST performed soil gas surveys as well as soil and groundwater sampling services for an environmental law firm representing the Orange County Water District at over 40 sites within the OCWD North Basin area. The sites included past aerospace industry properties that utilized organic solvents in their manufacturing processes. EST provided sampling and testing services as part of the assessment team assembled by the law firm. The objectives of the soil gas, soil and groundwater testing program were to identify potential sources of VOC contamination in groundwater within the OCWD North Basin area. Soil gas surveys were performed at multiple depths ranging between 10 and 70 feet below the ground surface. Individual and nested soil gas probes were installed and sampled by EST field technicians and chemists. Over 300 soil and soil gas samples were analyzed using EST’s mobile environmental laboratories. Environmental assessment activities and EST’s involvement with the OCWD North Basing project is ongoing.