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been met, the objectives of the proposed cleanup goals will be to meet the groundwater-specific criteria outlined in the policy. The Low-Threat Policy identifies five scenarios under the groundwater-specific criteria that can be evaluated to support case closure. The criteria for Scenario (4) of the policy are the most consistent with the Facility and are proposed for the site cleanup goals: a) Constituent plume exceeding water quality objectives is less than 1,000 feet. b) There is no free product. c) The nearest existing water supply well or surface water body is greater than 1,000 feet from the defined plume boundary. d) The dissolved concentrations of benzene and MTBE are each less than 1.0 mg/L. Goals (a) through (c) have been achieved for the Facility; however, as identified in Table 6, three wells still have concentrations of benzene and/or MTBE that exceed 1.0 mg/L. Therefore, the proposed cleanup goals for the COCs at the Facility are: COC Proposed Cleanup Goal(mg/L) Benzene 1.0 MTBE 1.0 5.2 Evaluation of Remedial Technologies A number of pilot studies have been conducted in the leasehold by various parties to assess possible technologies to address dissolved phase petroleum hydrocarbons in the subsurface. Ash Creek has reviewed the results of these pilot studies, as well as the application of other possible technologies to develop a recommended remedial approach for the Facility. Remedial technologies evaluated included: • Recirculation Bioaugmentation • Anaerobic to Situ Biological Treatment • Bioventing and Biosparging • Monitored Natural Attenuation • Ozone Injection • Groundwater Extraction and Treatment A brief description of each technology and its possible application at the facility is presented below. Revised Cleanup Plan Page 18 ak NuStar Stockton Terminal-Stockton,California November 7,2012 1014-12