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Stantec August 15,2013 Page 4 of 8 The LTCP is applicable to all petroleum UST sites subject to Chapter 6.7 of Division 20 of the Health and Safety Code as well as Chapter 16 of Division 3 of Title 23 of the California Code of Regulations. The LTCP states that UST cases are appropriate for closure pursuant to Health and Safety Code section 25296.10 if they meet the general and media-specific criteria outlined in the LTCP, and provided that site-specific conditions are not demonstrated to increase the risk associated with the residual petroleum constituents. With the absence of attributes of site-specific conditions that demonstrably increase the risk associated with residual petroleum constituents, the site meets the requirements for case closure outlined in the LTCP as described below: General Criteria a. The unauthorized release is located within the service area of a public water system. The site is located within the service area of California Water Service (CalWater). b. The unauthorized release consists only of petroleum. The release at the site was motor fuel from the former USTs and associated equipment. c. The unauthorized release has been stopped. The USTs and associated equipment were replaced in 1998, and removed in June 2013. d. Free product has been removed to the maximum extent practicable. Investigations at the site have not indicated the presence of free product. e. A conceptual site model that assesses the nature, extent, and mobility of the release has been developed. A conceptual site model was developed for the site and submitted to the SJCEHD on September 30, 2005. f. Secondary source has been removed to the extent practicable. Oxygen injection was conducted into sparge wells 1-2 through 1-5 on a biweekly to monthly basis from April 2009 through March 2013. Between 150 and 450 cubic feet of oxygen was injected into each well during each injection event, for a total of 98,400 cubic feet (8,758 pounds) of oxygen injected at the site since April 2009. Since that time, TPHg concentrations have decreased from 2,700 pg/L prior to remedial activities (first quarter 2009) to 720 fag/L during the most recent sampling event (second quarter 2013), and MtBE concentrations have decreased from 220 pg/L prior to remedial activities (first quarter 2009) to 1.9 pg/L during the most recent sampling event (second quarter 2013). Summaries of oxygen injection events and subsequent dissolved oxygen measurements are included in Tables 4 and 5. g. Soil and groundwater have been tested for MtBE and results reported in accordance with Health and Safety Code section 252926.15. All soil and groundwater samples have been analyzed for MtBE and reported to the CRWQCB since the UST replacement in August 1998. Summaries of soil and groundwater analytical results are presented in Tables 1 and 2, respectively. V:\1857\active\7- Eleven\active\185750063_711_14117\05_report_del iv\reports\14117_2013_08_15_closu re_report.doc