WASHINGTON --The Senate on Thursday blocked Sen. Lisa Murkowski's effort to limit for a year the Environmental Protection Agency's ability to regulate greenhouse gas emissions from power plants, factories and other stationary sources of pollution.

Murkowski, R-Alaska, had sought to amend the Interior Department appropriations bill being considered by the Senate, but was blocked from bringing forward her proposal.

It would have forbidden the EPA from working to regulate carbon dioxide emissions from power plants and large manufacturers even as the Senate continues to work on its own global warming proposal. It would not have prohibited the agency from continuing work on emission standards from mobile sources, such as automobile emissions.

Murkowski said she agrees emissions need to be brought in check, but said she didn't believe the EPA, acting under the authority of the Clean Air Act, is the proper agency to do so.

"Very clearly, stationary sources must reduce emissions in order to bring our nation to its climate goals," she said on the floor of the Senate Thursday. "But forcing them to do so through the Clean Air Act would be one of the least efficient and most damaging ways to pursue that goal. It would be rife with unintended consequences, and could be devastating for our economy."

Other senators disagreed, including Sen. Dianne Feinstein, D-Calif., who submitted letters objecting to Murkowski's proposal from the Alliance of Automobile Manufacturers, the Association of International Automobile Manufacturers and the United Auto Workers.

Feinstein also said that Murkowski's move sent the wrong signal to other nations as they ready for a United Nations summit on climate change in December.

"The amendment would send the wrong signal to the rest of the world about the Senate's intentions on climate change," Feinstein said. "It would suggest that we want to ignore the clear imperative to act, despite the efforts of the administration to motivate the international community in advance of the Copenhagen summit."

The EPA currently is working to comply with a 2007 Supreme Court decision, Massachusetts v. EPA, which required the agency to determine whether certain greenhouse gas emissions are harmful to the environment and public health. The EPA currently is in the middle of writing the final "endangerment finding" that would put the agency on the path of regulating greenhouse gas emissions.

If Congress doesn't act on legislation to cap emissions, the work the EPA is doing could emerge as the standard. The House of Representatives has passed legislation that would cap greenhouse gas emissions and create a market for trading pollution credits; the Senate has slowed in its effort but could release legislation in committee next week.

The EPA is a poor option fraught with all the pitfalls of a bureaucracy writing regulations, Murkowski said, and urged her colleagues to "step up and pass workable, intellectually honest climate legislation - whether a system of cap-and-trade, a carbon tax, or something else - that removes the Clean Air Act from the equation."

"Nearly every participant in this debate, from elected officials, to businesses and the environmental community, has stated their preference for legislation over regulation," Murkowski said.

Although the EPA's administrator, Lisa Jackson, has also said that she and the Obama Administration would prefer that Congress write laws regulating greenhouse gas emissions, the agency opposed Murkowski's proposal. The agency argued Murkowski's amendment would tie its hands on other regulatory matters, including issuing fuel standards for renewable fuels as well as enacting regulations under the Safe Drinking Water Act for capturing carbon and sequestering it to curb global warming.

The proposal also drew the ire of environmentalists and clean air advocates, who launched a full-out assault on Murkowski's amendment. Thursday, they were pleased the amendment failed to move forward.