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f s.I„� Eomrsr:u G. 43r:ovvn JK. <br /> P O.. <br /> MATTHEW RL']RIOUT2 <br /> SG:. [T/.Rv FOR <br /> f H41t7.I1+f IiTRI >:HOIF[:IIOr: <br /> Water Boards <br /> Central Valley Regional Water Quality Control Board <br /> �1 VED <br /> OCT <br /> 26 October 2012 31 ,,? <br /> PEAi;1T/S 'AOL�C tACTH <br /> Michael N. Oliphant <br /> Chevron Environmental Management Company <br /> 6001 Bollinger Canyon Road <br /> P. O. Box 6012 <br /> San Ramon, CA 94583 <br /> NO FURTHER ACTION REQUIRED DETERMINATION, FORMER VERNALIS PUMP STATION, <br /> VERNALIS, SAN JAOQUIN AND STANISLAUS COUNTIES <br /> Chevron Environmental Management Company (Chevron) submitted'a request for a No Further Action <br /> Required (NFAR) determination for the former Old Valley Pipeline (OVP) Vernalis Pump Station project <br /> (Site). The NFAR, dated 30 March 2011, was prepared by Science Applications International <br /> Corporation Energy, Environment & Infrastructure, LLC (SAIC), on behalf of Chevron. The Site is at <br /> 35500 Welty Road at the intersection with California State Highway 33, in the rural community of <br /> Vernalis in San Joaquin and Stanislaus Counties. The project encompasses a portion of the Highway <br /> 33 and Union Pacific Railroad (UPRR) right-of-way easements, which contained the historical OVP and <br /> the Tidewater Associated Oil Company (TAOC) crude oil pipelines, which are Chevron predecessor <br /> companies. In addition to the Highway 33 and railroad easements, nearbyladjacent land use includes <br /> agriculture and some rural residences. <br /> Central Valley Regional Water Quality Control Board (Central Valley Water Board) staff has reviewed <br /> the NFAR documentation and 2002 —2009 reports in the project files. Detailed comments are <br /> contained in the enclosed memorandum. <br /> In a letter to Chevron dated 2 December 2010, Central Valley Water Board staff concurred that soil and <br /> groundwater affected by crude oil leaks from Chevron's historical pipelines and pump station had been <br /> delineated, and additional characterization was not needed. It is not known if the land use(s) other than <br /> existing development will be considered. Groundwater monitoring wells previously associated with the <br /> Site were properly destroyed in 2009. <br /> SAIC's September 2010'human health risk screening evaluation, exposure to residual crude oil present <br /> in soil was determined to be 1E-06, equivalent to the U.S. Environmental Protection Agency threshold <br /> lifetime de minimus cancer risk of.1 E-06. This value indicates an acceptable cancer risk for exposure to <br /> onsite soils for a hypothetical future resident under the Site conditions evaluated. <br /> Future potential non-cancer health hazards from direct contact and indirect inhalation exposure to <br /> onsite soils, and the non-cancer hazards for individual chemicals'of potential concern (COPCs), were <br /> estimated. The exposure to onsite soils and non-cancer hazards from subsurface vapor intrusion, <br /> determined to be 3E-03, is well below the acceptable non-cancer hazard index of 1. Residual <br /> concentrations of crude oil remaining will naturally degrade with time, likely over several years. <br /> KARL E. La NGLEY SOD. P.E., C:-IAIr I PAMELA C. Gnvr DoN P.E.. SGEE, rxECuIIv_o=rlcry- <br /> 1685 E Streel,Fresno,CA 93746 j -watn_rgnflrry 3,ca.govlcent:RlvBlley <br /> �� IIC GvCK- ATCh <br />