SITE INFORMATION AND CORRESPONDENCE

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California Regional Water Quality Control Board Central Valley Region Karl E. Longley, SO, P.E., Chair go Linda S.Adams Secretary for 1685 E Street, Fresno,California 93706 i t; Arnold Environmental (559)445-5116•Fax(559)445-5910 LI ❑� V L� Schwarzenegger Protection http://www.waterboards.ca.gov/centralvalley Governor 19 November 2009 NO � 3 2009 EN%JlFiMtN1 HEALTH PERMIT/SERVICEC) M. Scott Mansholt Chevron Environmental Management Company 6111 Bollinger Canyon Road, Rm 3432 San Ramon, CA 94583 NO FURTHER ACTION REQUIRED, FORMER LYOTH LOADING STATION AND LYOTH OFFSITE, SOUTH BANTA ROAD, TRACY, SAN JOAQUIN COUNTY, CA Chevron Environmental Management Company (Chevron) submitted a request for No Further Action Required(NFAR) determination for the former Lyoth Loading Station and the Lyoth Offsite project sites (Sites). The NFAR, dated 17 April 2008, was prepared by Science Applications International Corporation (SAIC) on behalf of Chevron. The Sites are located in southern Tracy at 26501 and 26457 South Banta Road, respectively. Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff has reviewed the NFAR documentation and project files and detailed comments are contained in the attached memorandum. Based on the findings of a May 2005 investigation report, SAIC concluded that soil and groundwater affected by crude oil leaks from Chevron's historical Old Valley Pipeline (OVP) at the former loading station was adequately delineated and additional characterization was not needed. In addition, based on the findings of SAIC's May 2007 investigation report, Central Valley Water Board staff informed Chevron that affected groundwater at the Lyoth Offsite property was also delineated and additional characterization was not needed. Results of the findings indicate that crude oil affected soil and groundwater is limited in extent near the approximate center of the former loading station. A slightly larger elongated portion of affected soil extends offsite, beneath and generally within the historical OVP/railroad right- of-way easement. The extent of affected groundwater is slightly larger than and generally coincides with the areas of affected soil. Offsite, the areas of affected soil and groundwater is limited in extent and has been delineated. Six monitoring wells associated with the groundwater investigations on both Sites have been properly destroyed. According to the results of the investigations, the findings in the health risk assessment (HRA), and environmental risk evaluation reports, it is anticipated that the residual crude oil remaining in soil and/or groundwater on either Site would not present an unacceptable threat to human health for the adult/child resident or for the construction/trench worker scenario. The San Joaquin County Assessors records indicate that the former Lyoth Loading Station and the Lyoth Offsite properties are designated for commercial/industrial purposes. Review of the project files indicates that the anticipated future uses of the Sites are for commercial and/or industrial purposes. Based on historical project documentation, this is unlikely to change. The risk assessments for the Sites considered potential exposure by future onsite California Environmental Protection Agency 2d Recycled Paper