Gas is elusive. It's inevitable that some natural gas escapes during the drilling process, but new research suggests drilling operations in the Barnett Shale region are leaking more methane (CH4) than previously estimated.

Scientists at the University of Houston say this escaped methane may offset natural gas's environmental advantages over oil and coal.

Barnett Shale is a natural gas-rich rock formation in Texas, surrounding the Dallas-Fort Worth metropolitan area. The gas trapped in the ancient rock is hard to extract, and drilling operations have only recently begun there, thanks to advancements in hydraulic fracturing technologies.

With that uptick in natural gas production comes environmental hazards, researchers write in their new paper on the subject, published this week in the journal Environmental Science and Technology.

"In the past decade, the horizontal-drilling and hydraulic-fracturing techniques have led to a boom in natural gas production," researchers explained. "However, CH4 emissions associated with the production and transmission of natural gas have raised concern from several parties."

Scientists used a mobile laboratory to measure methane emissions near natural gas well pads, compressor stations and processing plants over the course of two weeks in October 2013. To get a baseline comparison, researchers also measured emission levels at places that naturally produce methane like wetlands and landfills.

In total researchers measured emissions near 125 well pads, 13 compressor stations, two gas processing plants and 12 landfills -- at 152 different facilities.

Rates of escaped methane ranged from 0.01 percent to 47.8 percent, with processing plants and compressor stations being the facilities most likely to leak the natural gas. Researchers say average emission rates were significantly higher than natural gas producers have predicted.

Researchers say the rates of methane release at some sites were egregious enough to make, in some instances, natural gas production more environmentally hazardous than coal or oil.

Natural gas, when burned, is more efficient at producing energy than other fossil fuels. But methane's greenhouse gas effect is 34 times more potent than CO2.

The research was funded by the Alfred P. Sloane Foundation and the Environmental Defense Fund.