SITE INFORMATION AND CORRESPONDENCE

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Pacific Car Wash • • December 2013 4405 Pacific Avenue, Stockton Claim No: 12325 Far Downgradient Well BENZENE Results for MW10A 3.5-I , 3 _._. 2.5 � 2 v m 1.s -- 0. _= BENZENTmnd Evaluation of Current Risk • Estimate of Hydrocarbon Mass in Soil: None reported. • Soil/Groundwater tested for MTBE: Yes. • Oxygen Concentrations in Soil Vapor: None reported. • Plume Length: <1,000 feet. • Plume Stable or Decreasing: Yes. • Contaminated Zone(s) Used for Drinking Water: No. • Groundwater Risk from Residual Petroleum Hydrocarbons: The case meets Policy Criterion 1 by Class 4. The contaminant plume that exceeds water quality objectives is less than 1,000 Na feet in length. There is no free product. The nearest water supply well or surface water body1s, greater than 1,000 feet from the defined plume boundary. The dissolved concentrations of benzene and MTBE are each less than 1,000 pg/L. • Indoor Vapor Risk from Residual Petroleum Hydrocarbons: The case meets the Policy Exclusion for Active Station. Soil vapor evaluation is not required because the Site is an active commercial petroleum fueling facility and the release characteristics do not pose an unacceptable health risk. • Direct Contact Risk from Residual Petroleum Hydrocarbons: Although no document titled "Risk Assessment'was found in the files reviewed, a professional assessment of site-specific risk from exposure through the direct exposure pathway was performed by Fund staff. The assessment of site-specific risk from potential exposure to residual soil contamination found that maximum concentrations of petroleum constituents remaining in soil will have no significant risk of adversely affecting human health. The Site is paved and accidental exposure to site soils is prevented. As an active petroleum fueling facility, any construction worker working at the Site will be prepared for exposure in their normal daily work. Page 12 of 14