Centrist Senate Democrats are pushing back against the Environmental Protection Agency’s recent move to begin regulating greenhouse gases and are warning that the agency risks overstepping its bounds — even as the House is taking the EPA’s action as a signal to move expeditiously on its own climate change bill.

“I’m very concerned about their unilaterally moving forward,— Sen. Ben Nelson (D-Neb.) said. “If alphabet agencies can do what they want without regard to what Congress believes, there’s something wrong with the system. In other words, just because we can’t get something through the Senate or the House or can’t get something done through Congress as a whole, doesn’t justify an alphabet agency jumping out and doing it on their own, even if they believe they have the authority to do it.—

Both moderate Democrats and Republicans have been concerned that regulation of carbon dioxide and other greenhouse gases will increase energy costs for consumers, and they have made a series of moves to try to temper whatever climate change legislation moves through Congress this year. But one of their biggest fears has been that the EPA would move forward on the issue without Congressional input.

“I do think that there will be a sense that Congress should make these determinations and not one of the agencies to set the broad policy for the country,— Sen. Mark Pryor (D-Ark.) said. “It puts the onus on us to do something and if we don’t, it sounds like the EPA, they’re going to.—

Sen. Debbie Stabenow (D-Mich.), whose state is reeling from job losses, also said she doesn’t support the EPA moving ahead on its own.

“It is much better to do something legislatively,— she said. “I would much rather see a balanced approach.—

The EPA’s declaration last week that greenhouse gases represent a public health threat is the first step to regulating emissions that are blamed for global warming, which scientists say is responsible for increased droughts, stronger floods and storms, and a rise in sea levels, among other threats to the environment.

That decision has been seen as a signal that the Obama administration is prepared to play hardball on the issue of climate change, and it puts pressure on moderate Democrats nervous about voting in the midst of a recession on a cap-and-trade plan that could increase costs throughout the economy.

“The Democrats, in some ways, are using that as a good cop, bad cop’ routine, saying that if we don’t do something up here, the evil’ EPA is going to do it,— said Sen. John Thune (R-S.D.), who added that he is concerned both the EPA and Democrats in the White House and Congress are “overreaching— and moving too far to the left on climate policy.

Whether or not the Obama administration is using the EPA to goose the Senate into action, centrist Democrats are clearly alarmed. However, many said they have not yet mapped out a plan of action.

Nelson said he would likely wait to see what the EPA comes up with, but he warned that Congress must be heard on the issue.

“They’re not going to run the government,— Nelson said. “They administer but they’re not going to make policy or set policy. … It’s not up to them.—

Centrist Democrats have plenty of friends on the Republican side of the aisle to help them rally the opposition to any EPA regulations that they believe go too far. Together, centrist Democrats and Republicans could attempt to pass a resolution of disapproval that would have the effect of nullifying any EPA regulation. However, the House also would have to pass the resolution, and the president would have to sign it.

“A government bureaucracy is not the place to write a cap-and-trade program that affects our economy in such a dramatic way,— Senate Republican Conference Chairman Lamar Alexander (Tenn.) said.

Alexander said President Barack Obama would be “extraordinarily unwise— to sidestep Congress and go the EPA route, saying it would spark a “huge backlash.—

Still, House leaders are eyeing the EPA decision as a way to help round up votes and push forward aggressively with legislation this spring.

“We need to recognize that it’s not a question of whether we’re going to deal with carbon emissions,— Energy and Commerce Chairman Henry Waxman (D-Calif.) said. “The question is whether Congress will.—

Rep. Ed Markey (D-Mass.), chairman of the Subcommittee on Energy and Environment, called the EPA ruling “the environmental equivalent of Brown v. Board of Education.

“We have the responsibility now to act,— he said.

Speaker Nancy Pelosi (D-Calif.) reiterated her intention to move a climate change bill.

“The commitment is real and we will pass legislation this year,— she said. “We don’t want another Earth Day to go by saying, What are we going to do about the climate crisis?’—

Waxman and Markey are holding hearings on the legislation through Thursday, and Waxman predicted a bill will be voted out of committee the week before the Memorial Day recess.