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Water Boards Central Valley Regional Water Quality Control Board 18 April 2012 01? �+ R 23 Michael N. Oliphant Chevron Environmental Management Company 6001 Bollinger Canyon Road P. 0. Box 6012 San Ramon, CA 94583 NO FURTHER ACTION REQUIRED DETERMINATION, CATELLUS PROPERTY, TRACY, SAN JOAQUIN COUNTY Chevron Environmental Management Company (Chevron) submitted a request for a No Further Action Required (NFAR) determination for the Catellus project (Site). The NFAR, dated 25 May 2011, was prepared by Science Applications International Corporation Energy, Environment ei Infrastructure, LLC (SAIC), on behalf of Chevron. The Site is northwest of Tracy along the app alignment of the historical Old Valley Pipelines (OVP), and Tidewater Associated Oil Company (TAOC) crude oil pipelines. The former OVP and TAOC (Chevron predecessors) pipelines were within the West Byron Road and the Union Pacific Railroad tracks right-of-way easements. Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff reviewed the NFAR documentation and project files, and detailed comments are contained in the enclosed memorandum. in a letter to Chevron dated 25 January 2011, Central Valley Water Board staff concurred that soil and groundwater affected by crude oil leaks from the historical pipelines had been delineated, and additional characterization was not needed. Fuel fingerprint evaluation by the laboratory, determined that the petroleum hydrocarbons present are consistent with weathered San Joaquin Valley crude oil. There are no groundwater monitoring wells associated with the Site. It is unlikely that future development will be considered in the future since the Site is developed with the highway, railroad tracks, and as a utility corridor. SAIC's October 2010 human health risk screening evaluation determined that exposure to residual crude oil components present in onsite soil was within the acceptable range of risk management and does not present an unacceptable health risk for a hypothetical onsite resident. The risk screening evaluation considered a conservative residential exposure scenario, but the likely future onsite use will be by construction/trench maintenance workers. The risk scenario considered by SAIC is a conservative estimate and actual risks are believed to be much lower. Additionally, an ecologica! receptor evaluation indicates threats to sensitive ecological receptors do not appear to exist and future land use is unlikely to provide suitable habitat. According to the findings and the risk evaluation, it is anticipated that the residual crude oil remaining will naturally degrade over a period of several years. Based on the investigation's findings, combined with the risk screening evaluation, the documentation provides the appropriate technical data and rationale to support an NFAR determination. _owc�� SCD, P.E�, e.i,�sr PAmr,a C �F[EL1pM .�. DCEE. exEcirin�_ ' '18=` 5iree' FrgSnc GF 9370i- www wUiertaaar0•r...now r.-enc:'arvakiH}