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1 ' <br /> November 22, 1995 <br /> Page 3 <br /> Previous Investigations <br /> Previous investigations concluded that there are areas of hydrocarbon-impacted soil and <br />' groundwater beneath the site A brief summary of Unocal's most recent investigations at <br /> the site are presented below <br /> A Phase I Environmental Site Assessment Report, dated January 8, 1994, was prepared by <br /> L M Swift and Associates (LMS) for Well Fargo The initial investigation included the <br /> results of a title search, physical characteristics of the site, historic site conditions, current <br />' conditions, review of regulatory agency records, and a review of the environmental <br /> database The assessment did not include a subsurface investigation✓ <br /> A Imuted subsurface investigation was conducted by LMS for Wells Fargo and is detailed <br /> in a Phase I Report, Addendum 1, dated March 29, 1994 The investigation included an <br /> underground electronic survey of the parking lot to determine if any abandoned USTs exist <br />' beneath the site, and exploratory borings to collect soil and groundwater samples Soil and✓ <br /> groundwater samples were collected from four hand-augered borings (B 1 through B4) <br /> completed to depths of up to 12 5 feet below ground surface (bgs) (Figure 1) The results <br />' of that investigation are as follows <br /> • The underground survey detected no large metal anomalies, and concluded that <br /> there were no USTs beneath the site <br /> • Groundwater was encountered in the borings at depths of approximately 10 feet✓ <br /> • Soil analytical results for total recoverable hydrocarbons (TRPH) ranged from <br /> 44 to 650 parts per million (ppm), benzene concentrations ranged from non- <br /> detect to 5 9 ppm The most sigl i cant hydrocarbon impact to soils appeared to <br /> be limned to the northern portion✓✓of the site at the groundwater interface <br /> • Hydrocarbon-impact d groundwater was detected in the northern portion of the <br />' site Groundwateralytical results for benzene ranged from non-detect to <br /> 650 parts per billion (ppb) <br /> APhase I Environmental Site.4ssessment, dated December 16, 1994, was prepared <br /> by Enviros Inc , for Unocal The site assessment concluded that twelve sites, in the <br /> vicinity of the Unocal site, have'een identified as having impacted soil and <br /> groundwater However, none of these sites were identified in the immediate <br /> upgradient direction from the Unocal site Additionally, the report concluded that <br /> two former service stations were located across from the Unocal site, a former Shell <br /> Oil service station at the northwest corner of 11th Street and Central Avenue during <br /> the period of approximately 1949 to 1962, and a former service station {possibly <br /> 3100971A/REPORT _ <br />