SITE INFORMATION AND CORRESPONDENCE

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Mr. Jeff Baker - 3 - 11• March 2009 Stockton Terminals TechnicalOmittee the STTC will prepare and submit a pilot study report, which will include evaluation of the data and recommendations. The STTC conducts monitoring at the Site pursuant to the requirements of Monitoring and Reporting Program (MRP) No. R5-2004-0823. Stantec conducted groundwater monitoring and sampling for the fourth quarter 2008 during November, and submitted the 31 January 2009 Fourth Quarter 2008 & Annual Groundwater Monitoring, and Remedial Summary Report (Annual Report). In the fall of 2004, the STTC began operation of two ozone sparge (OS) systems to clean up groundwater pollution migrating downgradient of the Site. The system is comprised of 57 A zone and 16 B zone wells connected to two five pounds-per-day (lbs/day) ozone generators. The OS system is divided into two portions. The west system is downgradient of Tesoro, and the east system is downgradient of BP. Between June and September 2008, the STTC estimates that the east system and west system had run times of 78 and 100 percent, respectively. The STTC is planning upgrades during the first quarter of 2009 with the objective of increasing system run times. The STTC monitors the ozone injection system using 12 A and B zone wells shown on the table on page 6.2 of the Annual Report. Six of the wells have been designated as remedial observation wells. A contingency plan is triggered if the concentration of benzene, toluene, ethylbenzene, and xylene (collectively BTEX) or methyl tertiary butyl ether (MTBE) in any of these wells, or TBA in the remedial observation wells, exceeds specified compliance limits. BTEX and MTBE concentrations in the ozone injection monitoring program wells were below compliance limits during the fourth quarter. Toluene, xylene, and TBA in remedial observation wells PS/MW-18 and AR/MW-18B exceeded compliance limits but not enough to warrant implementation of the contingency plan. The Annual Report also documented that, consistent with historical observations, separate phase hydrocarbon (SPH) sheen was observed in two A zone wells (TO/MW-1 and TS/MVV-2) on the Time Oil and Tesoro facilities. No STTC B, C, or D zone wells contained SPH. During the fourth quarter 2008, TS/MW-2 contained the highest concentrations of TPHg and TPHd at 240,000 micrograms per liter (pg/L) and 1,400,000 pg/L, iespeciively. Consistent with historical observations, the highest concentrations of BTEX were in BP tank farm monitoring well AR/MW-8A at 8,800 pg/L, 11,000 pg/L, 2,700 pg/L and 11,000 pg/L, respectively. TONT-2, located in the southwest entry area of the Time Oil and Tesoro facilities, typically contains the highest paired concentrations of TBA and MTBE. During the fourth quarter, however, the highest concentrations of MTBE and TBA were detected in BP tank farm wells AR/MW-50 and AR/MW-13C at 16,000 pg/L and 5,600 pg/L, respectively. The Annual Report contains monitoring results for the seven (PS/MW-20A through PS/MW-20D, OW-3CR, OW-3DR, and TS/MW-3D) newly-installed wells. The laboratory analytical results show the TPHg, TPHd, benzene and TBA concentrations in all new C and D zone wells exceed the WQOs for these constituents. Except for TBA, sample results for these constituents also exceeded the WQOs in the furthest downgradient D zone well, OW-5D.