DALLAS, Texas -- After simmering behind closed doors for more than 15 years, a disagreement between U.S. EPA and Texas environmental officials over air pollution permits has boiled over in a big way. Al Armendariz, the administrator of EPA's Region 6 office, has threatened to take over state programs, revoking three major permits and ordering the state's second-largest refinery to apply directly to EPA officials. Texas Gov. Rick Perry (R), never shy about challenging the federal government, has blamed the feud on the Obama administration, saying EPA would prefer a "less effective Washington-based, bureaucratic-led, command and control mandate." But while the feud has made national headlines thanks to Armendariz and Perry, air experts and former agency officials say the conflict, at its core, is the result of a long-dysfunctional relationship between the world's two largest environmental agencies -- EPA and the Texas Commission on Environmental Quality.