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Mr. Loeh.liu Caffey July 19,2006 Page 2 Gas Testing Instrumentation and Methods Testing for methane gas, oxygen gas,carbon dioxide gas and pressure was performed using a Lan.dtec Gena.-2000 or. Gastech GT-302 C7as Analyzer calibrated to methane gas. These instruments measure combustible gas concentrations in air directly on either of two scales, the first as percent by volume of the lower explosive limit(.LEL) of rnetbane gas in air(0 to 5 percent); the other as percent by volume (0 to 100 percent) in the gas sampled. The detection limit for both instruments is approximately 0.1.0 percent by volume. Gas monitoring well testing procedures are as follows: • Connect sample tubing, open test valve; observe pressure and.record data. • For probes 20 feet deep or less, turn on sample pump, observe and record methane, oxygen, and carbon dioxide gas concentrations, when readings have stabilized for 30 seconds. ® For probes more than 20 feet deep, tum on sample pump, extract a minimum.of one probe volume, observed and record methane,oxygen, and carbon dioxide gas concentrations, when readings have stabilized for 30 secoz).ds. ® Close test valve, disconnect sample instruments and secure sample location. SCS monitored structures by testing random selected locations where methane gas would most likely accumulate(e.g., electric outlets and junction boxes, conduits, drains, cabinets and closets). Other required monitoring documentation (e.g., sampling personnel, date, time and meteorological conditions) is shown on the attached testing data. tables. Gas 2%l!onitaring Well Testing In.accordance with,the approved testing schedule, all perimeter GP probes are to be tested at a -minimum., on a quarterly basis. During this reporting period, all accessible perimeter Gas Monitoring Probes defined as GP-Nos. l through GP-25 were tested for-the presence of LFG_ Fest results (shown on Table l) indicated that al 1 GP probes tested exhibited methane gas concentrations below the.LEL (5 percent by volume) or no methane gas was detected with the exception of GP-11 and GP-12 (up to 60.0 percent by volume). By May 23, 2006, methane gas concentrations detected at both probes b.addecreased to below the LEL in response to system adjustments and expansion. These results indicated that the subject site perimeter probes are in compliance with the requirements of Title 27 CCR Sections 2091.9.5 and 30931 through 20934.