Study links Texas quakes to oil companies' gas injections Workers attach pipes at a natural gas drill site in Bradford County, Pennsylvania. A cluster of earthquakes in Texas may be tied to oil companies injecting carbon dioxide into deep rock formations in the area, according to a paper released on Monday. The study, published in Proceedings of the National Academy of Sciences, is the first to document a correlation between earthquakes greater than magnitude 3 and the gas injection process. University of Texas seismologist Cliff Frohlich, who led the research, warned that the science was new and there was more work to do. Professor Frohlich and his colleague Wei Gan said gas injection at the Cogdell oilfield north of Snyder, Texas, may have sparked as many as 18 earthquakes with magnitudes of 3 or greater between 2006 and 2011 - including one that registered 4.4 on the magnitude scale. The earthquakes took place at a time when energy companies were increasingly using carbon dioxide to extract oil from the Cogdell field. US Energy Secretary Ernest Moniz has touted the potential of carbon dioxide to boost US oil recovery, while also indefinitely storing the greenhouse gas. At test injection sites in Australia, Algeria and Utah, recorded seismic activity has been negligible. Hearst newspapers