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Mr. Lochlin Caffey October 8, 2006 Page 2 0 Gas Testing Instrumentation and Methods Testing for methane gas, oxygen gas, carbon dioxide gas and pressure was performed using a Landtec Gem -2000 or Gastech GT -302 Gas 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 methane 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. 10 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, turn 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 seconds. • 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 Monitoring 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. 1 through GP -25 were tested for the presence of LFG. Test results (shown on Table 1) indicated that all GP probes tested exhibited methane gas concentrations below the LEL (5 percent by volume) or no methane gas was detected. These results indicated that the subject site perimeter probes are in compliance with the requirements of Title 27 CCR Sections 20919.5 and 30931 through 20934. Also, during this reporting period, SCS performed monitoring of temporary subsurface evaluation probe Nos. TGP-01 through TGP-39. Results of this testing indicated that most of these evaluation probes exhibited methane gas concentrations above the LEL (up to 58.6 percent by volume). Note, that the methane gas concentrations at these locations, which are for evaluation purposes and are not compliance locations, have indicated a decreasing trend. SCS is scheduled to perform fourth quarterly monitoring of 2006 (October through December) of the GP probes by the month of December 2006.