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„ FIELD PROCEDURES Site Safety Plan Field work will be performed by ERI personnel in accordance with a site safety plan developed for the site. This plan describes the basic safety requirements for the subsurface investigation and the drilling of soil borings at the work site. The site safety plan is applicable to personnel and subcontractors of ERI. Personnel at the site are informed of the contents of the site safety plan before work begins. A copy of the site safety plan is kept at the work site and is available for reference by appropriate parties during the work. The ERI geologist will act as the Site Safety Officer. Soil Borings and Sampling Prior to drilling of borings and construction of wells, ERI will acquire necessary permits from the appropriate agency(ies). ERI will also contact Underground Service Alert(USA) and a private underground utility locator before drilling to help locate public utility lines at the site. The driller will hand-auger boring locations to a depth of approximately 5 feet before drilling to reduce the risk of damaging underground structures. Soil borings will be drilled with a CME-55 (or similar) drill rig equipped with 8-inch-diameter, hollow- stem augers. Auger flights and sampling equipment will be steam-cleaned before use to minimize the possibility of crosshole contamination. The rinseate will be containerized and stored on-site. ERI will coordinate with Unocal for appropriate disposal of the rinseate. Drilling will be performed under the observation of a field geologist, and the earth materials in the borings will be identified using visual and manual methods, and classified as drilling progresses using the Unified Soil Classification System. Shallow soil borings will be drilled to approximately 15 feet below the uppermost zone of saturation or 5 feet into any competent clay layer (aquitard) encountered beneath the water-bearing zone. If an aquitard is encountered, the boring will be terminated and backfilled with bentonite before installing a groundwater monitoring well. Deep soil borings will be drilled to approximately 75 feet below grade. A bentonite plug will be placed above the screened interval within the water-bearing zone to prevent conduits. Cuttings generated during drilling will be placed on plastic sheeting and covered and left at the site. ERI will coordinate with Unocal for the soil to either be treated on site or removed to an appropriate recycling facility. One composite oil sample (4 brass sleeves) will be collected from the cuttings for chemical analysis and each sleeve will be sealed promptly with Teflon® tape and plastic caps. The samples will be labeled and placed in iced storage for transport to the laboratory. Chain of Custody Records will be initiated by the geologist in the field, updated throughout handling of the samples, and sent with the samples to the laboratory. Copies of these records will be in our report. Monitoring Well Construction Monitoring wells will be constructed in borings using thread jointed, 2-inch-inner-diameter, Schedule 40 polyvinyl chloride (PVC) casing. No chemical cements, glues, or solvents will be used in well construction. The screened portion of each well will consist of factory-perforated casing with 0.020- inch-wide slots. If unconfined aquifer conditions exist, the well screen will be installed from the total depth of each well to approximately 2 feet above the uppermost water-bearing unit. If confined conditions exist, the uppermost water-bearing unit will be screened exclusively. Unperforated casing will be installed from the top of each screen to the ground surface. The annular space in the well will be