The 112th Congress has just begun, and so have the attacks on the Environmental Protection Agency's ability to regulate greenhouse gases.

Three Republican House members -- Marsha Blackburn (Tenn.), Shelley Moore Capito (W. Va.) and Ted Poe (Tex.) have each introduced separate bills aimed at blocking EPA from regulating carbon dioxide and other greenhouse gases under the Clean Air Act.

The three measures hamstring the agency's authority in different ways: Blackburn's would "amend the Clean Air Act to provide that greenhouse gases are not subject to the Act," even though the Supreme Court ruled in 2007 that they are; Capito's would delay EPA from regulating carbon dioxide and methane for two years; and Poe's would prohibit any agency funding "to be used to implement or enforce a cap-and-trade program for greenhouse gases."

While Capito's bill is the most modest of the bunch, the West Virginia lawmaker explained in a statement that she has introduced a more limited bill because she thinks it has enough votes to pass and block initiatives such as new EPA permitting requirements that now require major new greenhouse gas emitters to show how they would use the best available current technology to lower their carbon footprint.

"Time is of the essence," she said. "The Democrats failed to act in any way to stop the EPA from implementing new rules pertaining to greenhouse gas emissions on January 2, 2011.Without congressional action to say otherwise, the EPA will continue to dismantle energy and manufacturing industries through regulation."

Franz Matzner, climate and air legislative director at the Natural Resources Defense Council, an advocacy group, decried the move.

"It sure didn't take long for big polluters to show what money can buy," Matzner said in a statement. "Banning or delaying the EPA from issuing any health safeguards whatsoever against carbon dioxide pollution would be nothing less than a dream-come-true for industries that would put profits ahead of our health and too many House members seem willing to do just that. It would be irresponsible for lawmakers to abolish the EPA's ability to cut carbon pollution, leaving polluters free to dump into our air without limit."

While one or more of these proposals may pass the House, it is unclear whether they can garner enough votes to pass the Senate. On Thursday Senate Environment and Public Works Committee Chairman Barbara Boxer (D-Calif.)--who kept her seat as well as her gavel despite last fall's GOP wave--issued a spirited defense of the EPA.

"EPA is following what the latest scientific research tells us about the threat posed by air pollution, including greenhouse gas pollution," Boxer said in her speech. "This committee will remain vigilant to ensure that politics and special interests do not interfere with the ability of the EPA and the states to act in accordance with the law to respond to what the scientists are telling us."

EPA officials could not be reached for comment on the new bills.