Republicans wasted little time in stepping up attacks on President Obama's choice to head the Environmental Protection Agency Tuesday after Obama announced new climate-change restrictions.

The nomination of Gina McCarthy to head the EPA was already in trouble before Obama's big climate-change speech, but Republicans said the new emissions limits the administration wants to impose on coal-firing plants guarantees stiff opposition to her confirmation on both sides of the aisle.

McCarthy now heads the EPA's air and radiation office, and has won praise from conservative Democrats and even some Republicans for working with business interests and GOP officials to forge compromises on air-pollution rules.

But McCarthy may have made a fatal mistake when she told the Senate Environment and Public Works Committee in April that the agency was not drafting any new emissions regulations.

"She responded to questions in the Senate at the [Environment and Public Works] committee and her responses suggest that she was either arrogant or ignorant - so I think this is going to impact her nomination," Sen. John Barrasso, R-Wyo. told The Washington Examiner Tuesday. "She has bipartisan trouble in the Senate, and that's why we haven't seen this nomination come to the Senate floor."

Barrasso was referring to written responses McCarthy submitted in April to the committee's top Republican, Sen. David Vitter, R-La.

No less than three times, McCarthy said the EPA was not — at the time — pursuing additional restrictions on power plant emissions.

Given McCarthy's written testimony, one industry lobbyist said the president's climate change announcements puts McCarthy in an untenable position.

"This all but kills her nomination," the lobbyist said. "The president has basically sacrificed her nomination in order to push for these regulations."

While technically correct for the moment when it was asked, McCarthy's assertion has Republicans fuming in light of Obama's Tuesday announcement of the first-ever U.S. limits on carbon emissions at existing power plants. Obama also announced that he would block the Keystone XL pipeline if its construction would exacerbate greenhouse gases.

Sen. Roy Blunt, R-Mo., already has a hold on the nomination because of a decades-long dispute over a floodway project on the Mississippi River that would decrease Missouri's vulnerability to flooding. He initiated the hold back in March, citing bureaucratic infighting and gridlock by federal agencies, including the EPA, involved in analyzing the environmental impacts of the project.

Sen. Claire McCaskill, D-Mo., also expressed deep concerns about the delayed floodway project.

A spokeswoman for Blunt said Tuesday that his hold on McCarthy's nomination remains.

Given Obama's new climate-change initiatives, Barrasso predicts McCarthy's nomination will attract multiple holds by senators and said opposition this year from Democrats and Republicans has already prevented Senate Majority Leader Harry Reid, D-Nev., from bringing her nomination to the floor for a vote.

Sen. Joe Manchin, a Democrat who represents coal-heavy West Virginia, slammed Obama's proposal, saying the "unreasonable restrictions" will have "disastrous consequences" for not only the coal industry, but also for American jobs and the economy. He didn't say directly on how the president's announcement would affect his vote on McCarthy.

Sen. Jim Inhofe, R-Okla., a leading opponent of many of Obama's environmental policies, said he expected Obama's announcement on emissions and the Keystone Pipeline project, calling it "payback" for the support he received from green groups during the 2012 election.

He predicted the new regulation will "starve out fossil fuels and make them so expensive that people will have no choice but to try to go to alternatives."

Unlike Barrasso, Inhofe said McCarthy's fate was already in doubt, and won't likely be influenced by Obama's Tuesday's remarks at Georgetown.

"I think [his decision to announce new regulations] reflects more negatively on Obama than it does on McCarthy, because he knows she made those statements," Inhofe concluded, referring to McCarthy's written testimony denying the agency was working on new power plant emissions restrictions.

Sen. Tom Udall, D-N.M., a member of the committee before which McCarthy appeared, said it would be a shame if Republicans use McCarthy's nomination to vent their distaste for Obama's environmental agenda,

"I'm really disappointed because I worked with her as an EPA commissioner and she was extraordinarily responsive and sensitive to the needs and interests of the business community," he said. "She knows how to strike a balance within the parameters of the law."

And as the Washington Post reported earlier this week, blocking her elevation may do little to affect the nature of new climate change regulations. She heads the EPA's air and radiation office and will be in charge of writing the rules for power plants if she remains in her current post.