A new study released by the oil and gas industry claims the Environmental Protection Agency (EPA) has been overestimating methane emissions from natural gas and fracking, but environmental groups have dismissed the study as “fatally flawed” and “biased.” The study, released by the American Petroleum Institute (API) and America’s Natural Gas Alliance (ANGA), claims methane emissions given off during natural gas production are as low as half of what the EPA is estimating. The study arrived just in time for a June 19 congressional hearing in which industry officials are testifying in defense of natural gas production and fracking, a relatively new drilling process that involves pumping thousands of gallons of water underground to break up shale formations in order to release natural gas and oil. The nonprofit environmental group Physicians, Scientists, and Engineers for Healthy Energy (PSE) has questioned the methodology behind the study. One criticism is that the study only covers 20 out of hundreds of oil and gas operators. This makes the study “statistically invalid,” according to Anthony Ingraffea, a professor of engineering at Cornell University and a member of PSE. Ingraffea also says questions for the study were framed poorly. In one example, he pointed out that the study gave survey-takers, which work within the oil and gas industry, EPA estimates of methane emissions. Given the industry’s interest in making sure methane emissions are low, this could have “coached” survey-takers into giving lower estimates, according to Ingraffea. Ingraffea says he would have preferred a study that randomly samples a larger number of operators from all over the country with more objective questions. That, he says, would have produced much more credible results. Ingraffea also emphasizes that the data from this study is made up of estimates derived by mathematical equations, not any actual measurements taken from the field. “No one, with one exception, has actually gone out into the field and made measurements,” he says. The one exception is a study by the National Oceanic and Atmospheric Administration (NOAA) that was published February in the Journal of Geophysical Research. The NOAA study measured Colorado gas wells in an attempt to get more accurate data than what the EPA and the industry have been providing. The measurements showed methane emissions were at least twice as large as what the EPA was previously estimating, leading NOAA researchers to conclude the EPA is greatly underestimating emissions, a stark contrast to the API/ANGA study.