Senate Democrats defeated a bill on Thursday that would have blocked federal environmental regulators from slashing power plant air pollution that blows downwind to other states and causes lung and heart problems.

     The bill, sponsored by Rand Paul, a Kentucky Republican and Tea Party favorite, needed only a simple majority of 50 to pass. The measure got only 41, while 56 voted against it. Only one Democrat, Joe Manchin from coal-rich West Virginia, voted for it.

     The measure would have blocked the Cross State Air Pollution Rule the Environmental Protection Agency finalized in July.

     The rule aims to slash air pollution from coal-fired power plants east of the Rocky Mountains. It would reduce sulfur dioxide emissions by 73 percent by 2014, from 2005 levels, when combined with state environmental laws. It would cut nitrogen oxide emissions by 54 percent by 2014.

     Republicans in the House of Representatives have passed a raft of bills that would delay or kill EPA clean air rules, but Thursday's vote was an indication of the tough battle they could face in the Senate.

     Six Republican senators, including Lamar Alexander, who offered his own clean air measure, voted against Paul's bill.

     The White House had indicated that President Barack Obama would have vetoed the bill had it passed in Congress.

     Barbara Boxer, the chairman of the Senate Energy and Public Works Committee, said the pollution the bill would have allowed to blow downwind would have been the equivalent of putting toxic trash on your neighbor's lawn.

     "I know all of us, 100 of us in this chamber would condemn it if somebody took all their garbage and put it on the lawn of the next-door neighbor," Boxer said on the Senate floor.

     Environmentalists and health groups cheered the vote.