Published: May 26, 2010 3:16 PM EDT
Updated: May 26, 2010 3:16 PM EDT

COVINGTON, La. (AP) - The Coast Guard has given BP approval to try to stop the oil leak in the Gulf of Mexico by pumping heavy mud into the well, but there's no word yet on when the attempt will start.

The Coast Guard said Wednesday it gave the approval for the "top kill" maneuver after consulting with government scientists. The top kill has never before been tried a mile beneath the sea, and company officials say it could be a couple of days before they know whether it is working.

Engineers hope to pump enough mud into the gusher to overcome the flow of the well. They plan to follow up the mud with cement that the company hopes will permanently seal the well. Millions of gallons of oil has spewed into the ocean since an April 20 rig explosion.