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w■ KLEINPELDER According to Chevron Pipeline Company, an 18-inch crude oil pipeline ruptured on December 4, 2003 at the subject site, releasing an estimated 750 barrels of crude oil to site soil (approximately 31,500 gallons). The pipeline carries crude oil from oil fields near Bakersfield to refineries in the Bay Area. The pipeline was reportedly ruptured during grading activities (ripping) of the soil for agricultural purposes by the farmer ' leasing the property. Chevron's consultant Cambria, documented emergency response and oil-impacted soil ' removal activities in a report titled "Emergency Response Environmental Report, Country Flags Release, Spatafore Property, 23577 Mountain House Parkway (Cambria Project #483-1858), dated March 11, 2004. Chevron workers reportedly arrived on the site on December 4, 2004 in an attempt to limit lateral migration of crude oil, recover free product with a vacuum truck and to remove contaminated oil saturated soil. Limited soil sampling and analyses and backhoe exploration was performed to assess the lateral and vertical limits of oil-impacted soil. Oil impacted soil was reported at depths ranging from 5 to 9 feet below ground surface (bgs), although vertical migration ' was noted as "ongoing." Therefore, the oil still appeared vertically mobile, potentially migrating to deeper depths over time. The apparent lateral extent of oil impacted soil is shown on Cambria's Figure 3 in this report, which shows an irregular shape area at approximate maximum dimensions of 380 by 380 feet. Chevron estimated that approximately 400 barrels were recovered (16,800 gallons) and ' that approximately 350 barrels still remain in onsite soil at the site (14,700 gallons). Based upon a visual survey of oil impacted soil, conducted by Kleinfelder and Siegfried Engineering, Inc. the area of impacted soil was estimated to encompass approximately 2.2 acres, extending north, east, west, and south of the pipeline rupture location (See ' Plate 2). Please note the footprint area has since been revised (See Plate 4). Based upon aerial photo review of the spill area, it appears the largest amount of oil settled to the east and northeast of the rupture following the crop lines and surface topography. San Joaquin County Environmental Health Division (SJC/EHD) requested a workplan ' for the purpose of assessing the limits of contaminated soils and groundwater quality beneath the site. That workplan (File No. 42428 / ST04P118) was prepared by Kleinfelder, dated March 22, 2004 and was submitted to SJC/EHD for review and comment. This workplan was subsequently approved by SJC/EHD. The following summarizes Kleinfelder's findings from implementation of that workplan. On May 19 and 20, 2004, a pushprobe soil and groundwater assessment was conducted. A total of twenty-nine (29) push probes were advanced during the field activities. A total of twenty-two 4-point composite soil samples, 26 discrete soil samples ' and 4 groundwater samples were submitted for chemical analyses for purgeable and extractable petroleum hydrocarbons and benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds. Twenty five (25) shallow probes were advanced to total depths t ranging from approximately 8 to 24 feet below ground surface (bgs). Four deeper groundwater pushprobes were advanced to total depths ranging from 44 to 58 feet bgs. Groundwater was noted approximately 43 feet bgs in these four deeper borings. 44843.T04/STO5R1333/DH:ly Page 2 of 17 t0 2005 Kleinfelder, Inc. October 25,2005