The Environmental Protection Agency should not wait for Congress before taking steps to control the gases blamed for global warming, supporters of US greenhouse-gas regulation said Monday. The EPA hearing is the first of two public forums on the agency's April finding that concentrations of carbon dioxide and five other greenhouse gases in the atmosphere pose dangers to human health and welfare - and that emissions from new motor vehicles and engines are contributing to the problem. The proposal could eventually lead to regulation of greenhouse gases under the Clean Air Act, starting with emissions standards for motor vehicles. "We must reduce greenhouse gas emissions now without further delay and without waiting for a perfect solution," said Navis Bermudez, speaking on behalf of New York Gov. David A. Paterson. "While we also hope that Congress enacts comprehensive federal climate change legislation, we believe EPA can act now under the existing Clean Air Act without waiting for such legislation." The House Energy and Commerce Committee planned to begin work later on Monday on legislation that, for the first time, would limit the emissions blamed for global warming from large industrial sources. The EPA proposal has put pressure on Congress to take action. "It is clear that the choice is no longer between doing something and doing nothing to curb greenhouse gas pollution. It is a choice between regulation and legislation," said Rep. Edward Markey, a Democrat. "We believe that the bill we have crafted in the Energy and Commerce Committee ... protects consumers and provides businesses with the certainty they need to adapt to our clean energy future." Which proposal will ultimately win out depends mostly on Congress. The House bill would largely pre-empt the EPA from forcing industries to reduce greenhouse-gas emissions under the Clean Air Act. Instead, it writes a new chapter that would put a price on each ton of pollution and allow industry to decide how to meet increasingly more stringent targets. President Barack Obama has made it clear that he prefers new legislation to cope with the problem. In his weekly radio address Saturday, the president called the bill "a plan that will finally reduce our dangerous dependence on foreign oil and cap the carbon pollution that threatens our health and our climate." The agency was compelled to weigh in on the threat posed by greenhouse gases after a 2007 Supreme Court ruling found them to be air pollutants. Industry groups and Republicans quickly sounded the alarm saying the finding could eventually prompt the EPA to regulate pollution from a whole suite of sources and burden an already troubled economy. That view was reiterated Monday by Bryan Brendle, director of energy and resources policy for the National Association of Manufacturers. Brendle told EPA officials the Clean Air Act was ill-suited to deal with the global problem of climate change and would "pre-empt ongoing congressional debate on an issue that would impact all sectors of a struggling economy." Supporters tried to head off those criticisms Monday. "We are concerned that other commenters have used hyperbole to describe the consequences of potential endangerment finding claiming it will wreak havoc ... we disagree strongly," said Nancy Kruger, deputy director of the National Association of Clean Air Agencies, which represents state and local air pollution control agencies. More than a hundred people are signed up to testify at the EPA hearing, including environmentalists, scientists, religious leaders and climate change skeptics. The House Energy committee intends to complete work and vote on the climate and energy bill by the end of the week. But Republicans concerned that the 932-page proposal will drive up energy prices and harm the economy are expected to drag out the proceedings by offering hundreds of amendments.