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Ms. Christina Carbajal April 24, 2006 Page 3 percent by volume were detected at any location tested,with the exception of GP-11 and GP-12 up to 58.5 percent by volume (see Table 1). During this reporting period, methane gas concentrations detected at Monitoring Probe Nos. GP-9, GP-11 and GP-12 have indicated a fluctuating trend in response to system.adjustments. SCS will continue to monitor Probe Nos. GP-9, GP-11 and GP- 12 weeldy as directed by the client. The next quarterly probe monitoring is due by the end of June 2006. Finally, on March 8, 2006, SCS performed monthly monitoring of Temporary Gas Probes, defined as TGP-01 through TGP-39,as directed by the Client. Results of this monitoring indicated that methane gas concentrations in excess of the LEL were detectedat several locations tested(up to 59.8 percent by volume). However, during their.reporting period, SCS has continued to observe a fluctuating trend in the detected methane gas concentration.Note, that these probes are intended :For evaluation purposes only and are not compliance locations(see Table 1). Uri-Site Structure nitori>a In accordance with the approved testing schedule,the interior of the on-site structures are to be tested quarterly. On March 27, 2006, SCS performed testing of the on-site structures (office, sacalehouse, breakroom) for the presence of LFG. Results of this testing indicated.that no methane gas was detected at any location tested(see Table 6). The next quarterly interior structure monitoring is due by the end of June 2006. LFG Extraction Well Testing System adjustments are required wheDever an extraction well exhibits an unacceptable change in Methane and/or oxygen gas concentration(which could be due to an overpull or underpull condition). Overpull occurs when the extraction rate of a particular extraction well exceeds that of the LFG generation rate within the radius of influence of the well. During this overpull condition, air can be drawn through the ground surface to the extraction well and then ultimately be injected into the flare, if an excessive overpull condition is allowed to continue for a long period, a significant drop in the methane gas content of the LFG and/or a subsurface landfill fire could occur. Underpull occurs when the extraction rate of a particular extraction well is less than the generation rate within the radius of influence of the well.. This condition could result in off-site subsurface LFG migration and/or surface emissions. Results of monthly testing of LFG extraction wells performed on March 4, 8 and 28, 2006 (see Table 3) indicate that several extraction wells exhibited an overpull and/or uraderpull condition. These conditions are necessary to maintain operational criteria(e.g. maintain a minimum 1.400 degrees Fahrenheit flare exit gas temperature) at the BFS and to help maintain/decrease methane gas concentrations at perimeter monitoring probes to below the LEL.