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Underground Storage Tank and Product Line Replacement Report-Tosco 76 Branded Facility No. 11195 Avril 23, 1999 Compounds (VOCs), reactivity, corrosivity, and ignitbility (RCI), total sulfides, total cyanide, and the metals antimony, arsenic, barium, beryllium, cadmium, chromium (III)., cobalt, copper, lead, mercury, molybdenum, nickel selenium, silver, thallium, vanadium, and zinc (CAM 17 metals). A total of approximately 67,500 gallons of groundwater was removed from the gasoline UST excavations by Walton during construction activities and stored on-site in portable tanks. Water sample W-STI was collected from this water for further disposal characterization purposes and analyzed for TPHg, BTEX, and MtBE. Water analytical data for samples Water-Ref and W-STI are summarized in Table 2. The water was transported by Waste Management Industrial Services, Inca (WMIS) of Benicia, California to the Tosco Refinery for treatment and disposal from January 19 to February 5, 1999. The WMI transportation manifests are attached. TEMPORARY CONDUCTOR CASING INSTALLATION Prior to backfilling and compacting of the former gasoline UST complex excavation, one conductor casing was placed near the northwest corner of the former UST excavation. The casing was installed to facilitate the removal of groundwater from within the former UST cavity. The conductor casing consisted of 11.5 vertical feet of 6-inch diameter polyvinyl chloride (PVC) and 10 horizontal feet of 6-inch PVC in an "L" configuration. The bottom 10 feet of the vertical casing and the horizontal casing consist of 0.02-inch machine slotted well screen. A locking well plug was placed on the top and a bottom cap was installed at the bottom end of the horizontal casing. In addition, two PVC conductor casings, one 6-inch diameter and one 10-inch diameter, were installed in the center of the new gasoline UST complex between the USTs. Each unslotted casing was plugged at the top with a locking well plug. These casings were installed to facilitate potential drilling beneath the USTs. A traffic-rated well box was installed over the top of each of the three casings. Installation of the conductor casings was approved by Mr. Michael Infurna of SJCEHD. REMEDIAL ACTIVITIES Remedial activities performed at the site include: • Removal of the primary source of petroleum hydrocarbon contaminants. The newly installed USTs, piping, and dispensers meet the 1998 EPA UST standards and are in compliance with SJCEHD requirements. • Removal of secondary source of petroleum hydrocarbon contaminants (hydrocarbon-impacted soil) to the extent practical. This includes removal of 1,017.19 tons of UST backfill sand and pea gravel from the former UST pits and overexcavation of all accessible areas impacted by petroleum hydrocarbons. The highest concentrations in soil remaining in place above 140193.03 6