"Drilling at several natural gas wells in southwestern Pennsylvania released methane into the atmosphere at rates that were 100 to 1,000 times higher than federal regulators had estimated, new research shows.

Using a plane equipped to measure greenhouse gas emissions in the air, scientists found that drilling activities at seven well pads in the Marcellus shale formation emitted 34 grams of methane per second, on average. The Environmental Protection Agency has estimated that such drilling releases between 0.04 grams and 0.30 grams of methane per second.

The study, published Monday in the Proceedings of the National Academy of Sciences, adds to a growing body of research suggesting that the EPA is seriously underestimating methane emissions from oil and gas operations. The agency is expected to issue its analysis of methane emissions from the oil and gas sector as soon as Tuesday, which will give outside experts a chance to assess how well regulators understand the problem."

Neela Banerjee reports for the Tribune Washington Bureau April 14, 2014. [2]