SITE INFORMATION AND CORRESPONDENCE

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Nofurther Action Required Determination _ q _ Former Lyoth Loading Station 19 November 2009 Lyoth Offsite concentrations reported were below applicable screening levels and the consultant concluded the exposure to residual crude oil compounds does not pose a threat to future residents/workers at the offsite property. • A Soil Management Plan (SMP) for both sites submitted in June 2009, describes procedures and contains the contact names and phone numbers for representatives of Chevron and the San Joaquin County Department of Environmental Health Department if future activities encounter crude oil affected soil. The SMP serves as a guideline for Chevron to implement for the handling, reuse, and disposal of any crude oil-affected soil and/or groundwater that may be encountered or excavated at either site. The SMP provides procedures for property owners, developers, and/or maintenance firms to follow that addresses such topics as trench excavations, dewatering, and health and safety guidelines. A copy of the SMP was provided to owners of the properties determined to overlie the area of affected soil/groundwater. • On 26 May 2009, Central Valley Water Board staff provided notification to the owner of the properties overlying affected soil/groundwater and to property owners within a 500- foot radius of the approximate boundary of the affected soil and/or groundwater at both sites. The notification stated that the Central Valley Water Board was considering a No Further Action determination for the sites and that comments should be submitted within 30 days. No comments were received. • Four onsite and two offsite groundwater monitoring wells associated with the project were properly destroyed in accordance with San Joaquin County guidelines in October 2009. Extent defined: Yes. Estimated Residual Petroleum Mass: Unknown. Petroleum occurs primarily as degraded petroleum hydrocarbons at approximate depths of between 6 and 15 feet bgs for both sites. The highest TPHc concentration of 70,000 mg/kg was detected at a depth of 13 feet bgs on the former Lyoth facility. Threat to Groundwater: The historical OVP pipelines were removed from service more than 35 years ago. The lateral and vertical extent of affected groundwater is limited, having slightly larger dimensions than the area of affected soil. Crude oil affected groundwater has been defined within and beneath the approximate location of the historical OVP right- of-way easement. Six water supply wells identified within a 2,000-foot radius of the project site(s) were either lateral/upgradient and/or well beyond the defined areas of affected groundwater. Considering the distance from the sites, it is unlikely that these wells will be affected by historical crude oil leaks. Additionally, it is unlikely that new groundwater wells will be installed considering the readily available City of Tracy municipal water supply. Threat to Human Health: • The exposure risk potential due to vapor inhalation was determined by the HRA documents to be within the acceptable risk range for the former Lyoth site. According to the HRA determination, chemicals of potential concern (BTEX and PAHs) are not present in groundwater. BTEX and PAH compounds detected in soil were limited to