The U.S. Environmental Protection Agency (EPA) says greenhouse gases (GHGs) threaten the public health and welfare of the American people, and that greenhouse-gas emissions from on-road vehicles contribute to that threat. This official "endangerment finding" is a necessary move to empower the Obama administration to impose new emission standards on automobiles, and to potentially opening the door for regulation on such large emitters as power plants, oil refineries, and chemical plants. The announcement comes on the opening day of the global climate summit in Copenhagen, Denmark. "Business leaders, security experts, government officials, concerned citizens, and the United States Supreme Court have called for enduring, pragmatic solutions to reduce the greenhouse gas pollution that is causing climate change," says EPA Administrator Lisa P. Jackson in the announcement. "This continues our work towards clean energy reform that will cut GHGs and reduce the dependence on foreign oil that threatens our national security and our economy." The Wall Street Journal reports that many business groups and lawmakers oppose the declaration, fearing the burden it will place on the economy. "[The declaration] could result in a top-down command-and-control regime that will choke off growth by adding new mandates to virtually every major construction and renovation project," says Thomas Donohue, president of the U.S. Chamber of Commerce. "The devil will be in the details, and we look forward to working with the government to ensure we don't stifle our economic recovery."