Rep. Ed Whitfield, R-Ky., filed resolutions on Monday opposing Obama's plan to impose new regulations on new and existing coal-fired plants. Senate Majority Leader Mitch McConnell was expected to follow suit late Monday or Tuesday.
The challenges by the two Kentucky Republicans were being filed under the little-used Congressional Review Act, which allows Congress to block executive actions with simply majority votes. The maneuver is subject to a presidential veto and has rarely been successful in overturning executive branch rules.
Still, it allows opponents to set up votes calculated to embarrass the Obama administration ahead of international climate talks in Paris this fall.
Republican senators are expected to tout the congressional challenge in a series of floor speeches starting Tuesday. One notable exception is New Hampshire Sen. Kelly Ayotte, who became the first GOP senator to support Obama's sweeping regulation that mandates carbon emissions cuts from the nation's power plants.
Ayotte, who is locked in a difficult re-election fight, said Sunday that the Clean Power Plan would "address climate change through clean-energy solutions that will protect our environment."
New Hampshire is already well on its way to meet the plans' goals, Ayotte said, adding that she would monitor the plan to ensure it does not have an adverse impact on state energy costs.
McConnell said in a statement that the regulations being imposed under the Clean Power Plan "make it clearer than ever that the president and his administration have gone too far — and that Congress should act to stop this regulatory assault."
The administration's "crusade for ideological purity" threatens the livelihoods of coal miners and their families in Kentucky and other states, McConnell said.
"These are Kentuckians who just want to work, provide for their families and deliver the type of low-cost energy that attracts more jobs to Kentucky. And coal is what allows so many of them do all that," he said.
The congressional resolutions follow court challenges filed Friday by industry groups and states dependent on fossil fuels. The challenges from all but two of the 25 states were filed by Republicans. They deride the plan as an "unlawful power grab by Washington bureaucrats" that will kill coal mining jobs and drive up electricity costs.
The Obama administration and environmental groups counter that the rules are needed to cut carbon emissions while curbing the worst impacts of climate change and sea-level rise. They also say the plan will spur new clean-energy jobs.
The new rules require states to cut carbon emissions by 32 percent by 2030, based on emissions in 2005. Each state has a customized target and is responsible for drawing up an effective plan to meet its goal.
The EPA says it has authority to enact the plan under the Clean Air Act.