"A large methane plume was spotted over northwestern Alabama near natural gas and coal sites three weeks ago -- though regulators have been unable to identify what spewed out the harmful greenhouse gas.
The Oct. 22 release was detected by satellite and pinpointed to an area in Marion County near natural gas wells in the Black Warrior Basin, a pair of gas pipelines and coal mines, some dating back to the late 1800s. An emissions rate of about 58 tons of methane per hour would have been required to generate the plume, according to an estimate from Kayrros SAS, which analyzed European Space Agency data.
The Alabama release is the fifth largest detected by the ESA’s Sentinel-5P satellite this year in the lower 48 U.S. states, according to Kayrros. State and federal regulators couldn’t identify the source with the satellite data, underscoring how difficult it is to use this greater visibility from space to take the next steps to understand the cause or to hold companies accountable."