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Former Lyoth Loading Station -2 - 26 August 2009 Lyoth Offsite historical OVP right-of-way and railroad tracks easement at the northeast property boundary. A smaller oval area of affected soil, less than 100-feet across, occurs near the western property boundary, extending offsite into the railroad easement. As indicated on the attached Figure, affected groundwater occurs: a) along a part of the loading station's northeast property boundary,b) within the OVP and railroad easement, and c) offsite from the loading station site to the northeast onto the Lyoth Offsite. The areas of affected soil and groundwater have been delineated on the former loading station site, including those that extend downgradient to Lyoth Offsite. There are four groundwater monitoring wells located on the parcel. LYOTH OFFSITE For investigation purposes, the area of affected groundwater downgradient of the loading station is referred to as Lyoth Offsite and has been addressed separately since approximately 2005. Two areas of affected soil extending from the former loading station property and a third smaller area of affected soil within the OVP/railroad easement have been defined. Additionally, the extent of affected groundwater offsite has been delineated including the area within the OVP and railroad easement (see the attached Figure). There are two groundwater monitoring wells on the offsite parcel. DISCUSSION In 1999, Chevron Environmental Management Company's (Chevron) consultant conducted a Health Risk Assessment (HRA) based on the anticipated future use of the former loading station. According to the findings, the total theoretical excess cancer risks determined were 1 X 10-6 to 1 X 10-5. The latter value is within or less than the California Environmental Protection Agency (Cal/EPA) generally acceptable risk range of 1 X 10-6 to 1 X 10-4, indicating there should be no unacceptable health risk to future residents. The HRA, based on a potential exposure scenario for an adult or child resident, was submitted for review by the California Office of Environmental Health Hazard Assessment (OEHHA). In an April 2002 addendum to the HRA, OEHHA staff concurred that review of additional inhalation pathway data, indicated changes to total risk resulted in a 7 X 10-7 to 2 X 10"5 exposure risk. The additional findings are consistent with the previous findings of no unacceptable risk for future residents. OEHHA approved the HRA stating that "risk between 10-6 and 10"4 are within the range of risk management, wherein other factors, along with risks, may be used to evaluate the acceptability of the risk". The total non-carcinogenic hazard indexes (HI) are 0.1 and 0.02, which are less than the target HI of 1. In January 2009, Chevron's consultant submitted an Environmental Risk Evaluation (ERE) for the Lyoth Offsite property. The consultant used applicable environmental screening levels for the evaluation of potential risk to human health and the environment. According to the findings, affected soil has not been observed at less than 10 feet bgs, therefore no exposure pathway exists and thus no risk for future site residents or site workers. Direct exposure to petroleum chemicals of potential concern by future construction/trench workers at the site were compared to applicable environmental screening levels. The analytical results reported are less than respective screening levels and thus, exposure to petroleum chemicals of potential concern does not pose a threat to future construction/trench workers. Additionally, according to the consultant's ERE report, threatened, endangered, or sensitive species do not occur within a one-mile radius of the sites.