"A study of abandoned oil and gas wells in Pennsylvania finds that the hundreds of thousands of such wells in the state may be leaking methane, suggesting that abandoned wells across the country could be a bigger source of climate changing greenhouse gases than previously thought.
The study by Mary Kang, a Princeton University doctoral candidate, looked at 19 wells and found that these oft-forgotten wells are leaking various amounts of methane. There are hundreds of thousands of such oil and gas wells, long abandoned and plugged, in Pennsylvania alone, and countless more in oil and gas fields across the country. These wells go mostly unmonitored, and rarely, if ever, checked for such leaks.
A growing list of studies conducted over the past three years has suggested that crude oil and natural gas development, particularly in shale formations, are significant sources of methane leaks — emissions not fully included in U.S. Environmental Protection Agency greenhouse gas inventories because they are rarely monitored. Scientists say there is inadequate data available for them to know where all the leaks are and how much methane is leaking."