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ATTACHMENT C FIELD AND LABORATORY PROCEDURES Chevron 9-6258, 2409 East Main Street at F Street, Stockton, CA Health and Safety As required by the Occupational Health and Safety Administration (OSHA) Standard "Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910.120), and by California Occupational Health and Safety Administration (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192), SECOR will prepare a Site-Specific Health and Safety Plan prior to the commencement of fieldwork. The Site-Specific Health and Safety Plan will be reviewed by the field staff and contractors before beginning field operations at the site each day. Exploratory Drilling and Soil Sampling The boring will be drilled to a depth of approximately 60 feet bgs. The boring will be advanced using 8-inch hollow-stem auger drilling equipment and logged by a SECOR representative using the Unified Soil Classification System and standard geologic techniques under the direction of a Registered Geologist. Soil samples for logging will be collected at 5-foot depth intervals using a California-modified split-spoon sampler. The sampler will be driven a maximum of 18 inches using a 140-pound hammer with a 30-inch drop. Soil samples for chemical analysis will be retained in brass liners, capped with Teflon squares and plastic end caps, and sealed in clean zip-lock bags. The samples will be placed on ice for transport to the laboratory accompanied by chain-of-custody documentation. Down-hole drilling and sampling equipment will be steam-cleaned prior to and following the completion of the soil boring. Down-hole sampling equipment will be washed in a tri-sodium phosphate or alconox solution between samples. Groundwater Monitoring Well Installation and Sampling The boring will be converted to a groundwater monitoring well by installing 2-inch diameter, flush-threaded, Schedule 40 PVC casing with 0.020-inch factory-slotted screen. Approximately 15 feet of screen will be placed in the bottom of the boring. A grade of sand appropriate to the screen size will be placed in the annular space across the entire screened interval, and will extend approximately 2 feet above the top of the screen for the well. A bentonite seal will extend two feet above the sand pack. The monitoring well will be completed with neat cement from the bentonite seal to ground surface. The well casing will be topped with a locking cap. The wellhead will be contained in a watertight well box, either traffic rated and flush mounted or in a "stove-pipe" arrangement. The boring logs will show the well construction details. The well will be developed after completion. The development procedure for the well will consist of pumping or bailing water from the well until the water is visibly clear, the well goes dry, or until a maximum of ten casing volumes have been removed. After development, water levels will be allowed to partially recover. Groundwater samples will then be collected using a disposable teflon bailer, placed into appropriate EPA- approved containers, labeled, placed on ice, and transported to the laboratory accompanied