When no other metadata was available, owline routing provided by ECMC was used to augment existing metadata. Flowlines are pipelines which connect wellheads to the liquid/gas separation equipment on wellpads. For example, a wellpad report record from CDPHE may have specied a wellhead location, rather than the wellpad location. Assuming the wellpad was detected by satellite recognition and a owline between the two was reported, the owline routing could be used to assign the misplaced wellpad metadata to the true wellpad location. A mapping example of production facilities is shown in Figure . This method recovered metadata for 360 facilities (2.9%). Since all events reported by partners originated, by denition, from a facility, any event locations not matched to a facility from one of the public sources were added to the facility list (173/1.4% of facilities). These additions include pigging locations where pigging operations occurred and one pipeline leak location detected by the aircraft and veried by the study team. emissions from these units may be larger than fugitive emissions at the facility. The majority of units utilized gas-fueled drivers (51% reciprocating engines and 18% turbines). emission rates vary over two orders of magnitude depending upon the type of engine. Since combustion slip is both hot and dilute (1000-2500 ppm v is typical ), it often does not form the well-dened plumes characteristics of cold point sources like vent stacks or leaks. Combustion slip also occurs in heaters of gas upgrading equipment. Compressors also include large (2-5 kg/h) vented sources such as rod packing and shaft seals vents that are co-located with compressor driver emissions.