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t Ms. Christina Carbajal. July 19,2006 Page 2 If the methane gas component of LFG is allowed to accumulate in a confined area(i.e., utility lines,irrigation valve boxes, vaults,basements,wall spaces, etc.)and is exposed to an ignition. source, it can be explosive at concentrations between 5 and 15 percent by volume. At higher concentrations, methane gas is flammable. However,the presence of methane gas in site soil does not mean there is an immediate threat of explosion because flames cannot typically propagate through soil. Operation Criteria The most current Permits to Construct/Operate dated.July 22,2002 and October 8, 2002, issued by the San Joaquin Valley Unified Air. Pollution Control District (SJVUAPCD)delineates several. main operational criteria for the subject system. This operational criteria states that flare exit gas temperature be maintained at a minimum of 1400 degrees Fahrenheit during system operation. In addition the systems are to be operated to maintain compliance with.SJVUAPCD Title V and Rule 4642 requirements. State California Code of Regulations (CCR Title 27)requires that solid waste disposal site owners/operators implement LFG control or monitoring provisions to ensure that methane gas concentrations in soil at the property line do not exceed the lower explosive limit(LEL, or 5 percent by volume) and that interiors of onsite structures do not exceed 1.25 percent methane by volume in.air. Gas Testing Testing for methane gas(the combustible component of LFG), oxygen gas, carbon dioxide gas, pressure,and temperature was performed using a Landtec Gem-2000 Gas Analyzer or comparable unit. This instrument measures combustible gas concentrations in air directly on either of two scales: the first as percent by volume of the lower explosive limit(LEL)of methane gas in air (5 percent), the second as percent by volume (0 to 100 percent) in.the gas sampled.. Instrument calibration.forms are attached.to this report. LFG Monitoring Probes In accordance with the approved testing schedule,LFG Monitoring Probes(GP) are to be tested quarterly or when methane gas concentrations detected exceed 5 percent by volume. During this :reporting period,all perimeter LFG monitoring probes defined as Nos. 9 and 11. through 25 were tested for the presence of LFG. Results indicated that no methane gas concentrations in excess of 5 percent by volume were detected at any location tested. SCS will continue to monitor Probe Nos. GP-9,GP-11 and GP-12 weekly as directed by the client. The next complete quarterly probe monitoring is due by the end of September 2006.