Scientists have found that oil and gas fields along Colorado's Front Range have been emitting three times more methane and nearly eight times more cancer-causing benzene than previously thought.
A study by the National Oceanic and Atmospheric Administration and partly supported by the Environmental Defense Fund is based on data gathered in 2012 from aircraft flying over drilling zones north of Denver.
The Denver Post reports that for years, health and environmental officials have estimated air pollution primarily by measuring ground-level sources. State agencies didn't begin monitoring methane until 2012, and the new study marks one of the first efforts to investigate pollution in the atmosphere above ground level.
Colorado Oil and Gas Association representatives declined to comment, saying they haven't reviewed the study.