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Mr. Mike Infurna <br /> ConocoPhillips Site No. 5449, Former Thrifty Oil Company Station No. 172 <br /> May 12, 2010 <br /> Page 2 <br /> Groundwater Extraction (GWE) System: <br /> Several missing groundwater pumps <br /> Missing air compressor <br /> Some piping repair necessary. <br /> In addition, the electrical conduit will need to be replaced and inspected by PG&E before it <br /> can be connected to the meter. Stantec has inquired and found that this work will require a <br /> building permit, which is being acquired. <br /> After receiving the monitoring results, Stantec evaluated options to replace, repair, or <br /> redesign the system. Due to the extensive damage and loss of parts to the SVE system, <br /> repair of the existing SVE unit does not appear feasible. Groundwater concentrations are <br /> such that groundwater remediation will likely be required to continue. While we are <br /> evaluating the existing GWE system to determine if GWE is to be continued or if another <br /> form of groundwater remediation such as air sparging will be pursued, we will restart SVE <br /> with another unit to check for vapor rebound as requested by your agency. <br /> A SVE unit available from another location in Fort Bragg has become available, and PG&E <br /> has verified that power requirements for this unit can be met at the site. Stantec will <br /> expedite obtaining a new air discharge permit from the San Joaquin Valley Air Pollution <br /> Control District. We plan to run the SVE system for approximately one to two quarters to <br /> help lower dissolved concentrations in the wells, evaluate the concentrations, and then <br /> consider the path forward for groundwater cleanup. Pending approval of permits, a PG&E <br /> inspection, and mobilizing and connecting the SVE unit, we anticipate that the SVE system <br /> will be running in June 2010. <br /> Due to the condition of the remediation system, Stantec was not able to complete the <br /> rebound testing deadline established by the SJCEHD. However, if the SVE system can be <br /> started in June 2010 as planned, meaningful rebound testing data can be included in the <br /> third quarter report. We request an extension of the rebound evaluation reporting date from <br /> July 17 to October 15, 2010. <br /> Based on review of historical groundwater monitoring data, Stantec previously <br /> recommended that the site be monitored and sampled semiannually during the second and <br /> fourth quarters. Due to the lack of monitoring data during the last three quarters of 2009, <br /> we recommend that groundwater monitoring and sampling be performed during the third <br /> and fourth quarters of 2010. After these results are available, Stantec will reevaluate the <br /> recommendations previously made in our 2009 and 2010 quarterly status reports and Site <br /> Conceptual Model. We expect to be able to make recommendations regarding further site <br /> assessment and remediation in the fourth quarter report due January 15, 2011. We <br /> anticipate that a work plan, as appropriate, can then be submitted by March 31, 2011. <br /> Per the request of the SJCEHD, the April 16, 2010 EDF and Geo_Well files were uploaded <br /> to GeoTracker on May 3, 2010, confirmation no. 6904267311 and 6175195157, <br /> respectively. <br /> 5449 Extension Request Letter,5-10.doc <br />