The report gives results of a pilot study of six U.S. landfills that have methane (CH4) gas recovery systems. NOTE: The study was a first step in developing a field testing program to gather data to identify key variables that affect CH4 generation and to develop an empirical model of CH4 generation based on those variables. The field test program development, in turn, is part of EPA/AEERL's research program aimed at improving global landfill CH4 emissions estimates.) o evaluate the effects of climate on CH4 production and recovery, the six sites represented a variety of moisture and temperature patterns (i.e., hot and wet, cool and wet, hot and dry). andfill gas was tested at each landfill to evaluate the quality of the gas recovery data available at each. The testing included assessing the adequacy of on-site instrumentation and scanning the landfill surfaces for organic vapors that would indicate emissions of CH4. n addition, information on waste composition and landfill characteristics was sought for each landfill. xcept for flow measurements, the test procedures selected were well suited to the types of gas recovery installations encountered at the landfills visited. ased on comparisons between EPA Reference Method 3C and instrument analyses of the landfill gas composition, all on-site analysis instruments appeared to be operating with reasonable accuracy.