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12 May 2010 AGE-NC Project No. 09-1692 Page 2 of 4 Prior to mobilization,the area of excavation will be clearly marked and an utility clearance obtained through Underground Service Alert. Permits required from other agencies will be procured. 2.2. SOIL EXCAVATION The lateral distribution of petroleum hydrocarbon-impacted soil extends approximately 80 feet towards the southeast, 50 feet towards the northeast, and 30 feet towards the southwest from the center of the dispenser island located under the fueling canopy. The lateral extent is undefined towards the west beyond boring B2 (Figure 3). The highest concentrations of impacted soil were encountered in samples collected beneath the dispenser island area and south of the truck wash area, at depths between approximately 5 feet and 10 feet below surface grade(bsg).Analytical results of soil samples are summarized in Table 1. AGE proposes to excavate two areas (Area A and Area B) on site, to maximum depths of 10 feet bsg, to remove approximately 325 cubic yards (410 tons) of impacted soil. Approximately 607 square feet of soil will be removed from Area A, located under the fueling canopy. Approximately 271 square feet of soil will be removed from Area B,located south of the truck wash area. Soil will be excavated utilizing a backhoe and stockpiled on-site. The proposed extent of the soil excavation and stock pile location are depicted in Figure 3. Soil will be screened for volatile organic compounds in the field using a organic vapor meter(OVM) during excavation activities. Using OVM measurements and visual evaluation, soil will be segregated into "clean"and"impacted" stockpiles. 2.3. SOIL SAMPLE COLLECTION AND ANALYSIS Following CVRWQCB Tri-Regional Board recommendations, soil samples will be collected from the base and each side wall of the excavations at a minimum interval of every 20 linear feet and from the base of the excavation at a minimum of one sample for every 400 square feet of excavation area. Composite (4:1 per 100 cubic yards) samples will also be collected from stockpiles (both "clean"and"impacted") for disposal characterization purposes. Field procedures for collection of soil samples are presented in Section 3.2. Each soil sample will be analyzed by Cal Tech Environmental Laboratories (CTEL), a State of California Department of Public Health(CDPH)-certified laboratory,for the following constituents: • Total petroleum hydrocarbons quantified as diesel (TPH-d) in accordance with EPA Advanced GeoEnvironmentnl,Inc.