SITE INFORMATION AND CORRESPONDENCE

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California Stop September 2013 2224 Manthey Road, Stockton Claim No: 18428 unlikely that they will be, considering these factors in the context of the site setting. Remaining petroleum hydrocarbon constituents are limited and stable, and concentrations are decreasing. Corrective actions have been implemented and additional corrective actions are not necessary. Any remaining petroleum hydrocarbon constituents do not pose a significant risk to human health, safety or the environment. Rationale for Closure under the Policy • General Criteria: The case meets all eight Policy general criteria. • Groundwater Specific Criteria: The case meets Policy Criterion 1 by Class 5. This case does not meet Policy Criteria 1 by Class 1 through Class 4 because irrigation wells are located within 1,000 feet of the Site. However, the MTBE/TBA plume is stable and decreasing in the directions of those wells and is also limited to the Site boundary. The monitoring data strongly suggest biodegradation occurring at the Site. The contaminant plume that exceeds water quality objectives is less than 250 feet in length. There is no free product. There are no public supply wells regulated by the California Department of Public Health within 1,000 feet of the defined plume boundary. No surface water body is located within 1,000 feet of the defined plume boundary.The regulatory agency determines, based on an analysis of site specific conditions, which under current and reasonably anticipated near-term future scenarios, the contaminant plume poses a low threat to human health and safety and to the environment and water quality objectives will be achieved within a reasonable time frame. • Vapor Intrusion to Indoor Air: 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. • Direct Contact and Outdoor Air Exposure: The case meets Policy Criterion 3b. Although no document titled "Risk Assessment" was found in the files reviewed, a professional 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. Even though maximum concentrations in soil are higher than those in Policy Table 1 for Commercial/Industrial use, and the concentration limits for a Utility Worker are exceeded, the impact were limited to the shallow soil in the dispenser area. The dispenser area was subsequently upgraded and the release stopped. The area is capped with concrete and accidental access to site soils is prevented. As an active commercial petroleum fueling facility, any construction worker working at the Site will be prepared for exposure in their normal daily work. Determination The Fund Manager has notified the tank owners or operators and reviewed the case history of their tank case. The Fund Manager determines that closure of the tank case is appropriate based upon that review. The Fund Manager has prepared this review summary report summarizing the reasons for this determination, provided the Review Summary Report to the applicable regional board and local agency, as appropriate, with an opportunity for comment on the Review Summary Report_ Pursuant to Health and Safety Code as of the date of the signature of the Fund Manager below, the regional board or local agency shall not issue a corrective action directive or enforce an existing corrective action directive for the tank case until the board issues a decision on the closure of the tank case, unless one of the following applies: (A) The regional board or local agency demonstrates to the satisfaction of the manager that there is an imminent threat to human health, safety, or the environment. Paae 2 of 13