The Permian Basin, located in western Texas and southeastern New Mexico, is the largest oil- and gas-producing region in the U.S. The oilfield operations emit methane, but quantifying the greenhouse gas is difficult because of the large area and the fact that many sources are intermittent emitters. Now, researchers reporting in ACS' Environmental Science & Technology Letters have conducted an extensive airborne campaign with imaging spectrometers and identified large methane sources across this area.