Most plumes detected combusted and vented emissions: Approximately 20% of midstream plumes show visible transport where the origin of the plume can be clearly identied on the facility (Table ). The remainder of plumes show little transport; the plume indicates a general methane enhancement, typically over the main equipment at the facility. Figure and Table illustrates that facilities with multiple detections generally have higher estimated emissions, and that in the majority of cases when a facility had more than one plume, the plume was located on the same location on each detection, over the compressor building (Table However, not all midstream plumes are consistent with compressor or processing emissions. Midstream facilities may also have large fugitive emissions, notably from isolation and blowdown valves, valves on liquid separation equipment, or combustion issues with ares. These fugitive sources tend to be located away from compressors or processing equipment, and are typically concentrated point sources. These data suggest that the majority of midstream plumes may be explained by detections of known compression and processing emissions.