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Contaminant concentrations have further decreased substantially since active remediation by i" ozone injection started five years ago and in many cases have become non-detect. The residual mass of gasoline in groundwater is well defined with very little gasoline remaining. The remaining contaminants currently do not pose a threat to human health and safety due to the low quantity of gasoline remaining and the lack of any expected uses for the shallow groundwater. The last of the Groundwater Quality Objectives are expected to be reached in twelve years. A soil vapor surrey was performed to determine if vapor intrusion into indoor air, for any future building, may be a concern, and as a side benefit, give an indication if any petroleum hydrocarbon impacted soil remains. The soil vapor survey results were non-detect at or above the laboratory reporting limits for all analyzed compounds. As a result, there is no risk to human health and safety due to potential vapor intrusion. Due to the soil vapor survey results and the ozone sparging of the soil excavation pits for over four years, there is no expectation of any significant soil contamination from petroleum hydrocarbons remaining in the vicinity if the former underground storage tanks (USTs). 11.0 RECOMMENDATIONS Based on the results of the work conducted at the subject site over the last ten years and the �. overall history and use of the site, JJW recommends that the eleven monitor wells and twelve sparge point locations should be properly destroyed, and the site closed with a "no further action required" letter issued by the appropriate regulatory agencies and in line with State Water Resources Control Board recommendations for closing these older sites. L. 12.0 LIMITATIONS The lack of identification of contamination on a site does not preclude its existence. JJW Geosciences incorporates the current, standard of care when making judgments concerning the presence of contamination on a site. However, due to natural circumstances, it is not always possible to identify and/or accurately determine the presence of contamination. Additionally, changes in appropriate standards may occur, whether they result from legislation, the broadening of knowledge, or other reasons. Such changes may invalidate certain findings of this report. �- This report has been prepared for the exclusive use of the client and is applicable only for the subject site. JJW Geosciences is not responsible for interpretations by others of the data presented in this report. This report does not represent a legal opinion and no warranty is L. expressed or implied. This report is issued with the understanding that it is the responsibility of the property owner to ensure that the information and recommendations herein are brought to the attention of the appropriate regulatory agency. This work was performed in accordance with the generally accepted standards of care existing in Northern California at the time of the investigation. V LN g JJW GEOSCIENCES Inc.