The Bush administration last week reaffirmed its commitment to strengthen diesel-engine standards but at the same time to rollback enforcement efforts against aging coal-fired power plants after receiving separate Congressional requests that it reconsider. According to the Washington Post, House Speaker Dennis Hastert (R-IL) and other Republican lawmakers urged the administration to postpone a new standard for long-haul diesel trucks at the urging of Caterpiller, Inc., a leading truck manufacturer based in Illinois, which will face stiff penalties for noncompliance when the regulation is implemented in the fall. The standard grew out of a consent decree in 1998 between the Clinton administration and seven leading tucking companies, including Caterpiller, which for years unlawfully deceived the government about compliance with clean air regulations. Several of these companies (Cummins Inc. and Mack Trucks Inc.) have been able to develop technology to meet the new requirements, which are expected to reduce emissions of nitrogen oxide by 1.2 million tons within a year, and have argued, successfully, that the administration move forward. Meanwhile, Sens. Joseph Lieberman (D-CT) and John Edwards (D-NC) released a letter signed by 44 senators asking that the administration postpone its plans to relax enforcement of the Clean Air Act’s New Source Review program, requiring older power plants to make upgrades to control pollution. "[B]ecause the specific changes proposed have not been subject to careful study and full public comment, we have serious concerns that the changes could allow more air pollution -- causing more asthma, more heart and lung problems, and more premature deaths," the senators wrote. Administration officials dismissed the letter, signed by three Republicans, as "political posturing," according to the Post.