Topkill Fails

BP announces the failure of its "topkill" plan to plug the Oilmaggedon leak.

BP began a risky operation known as "top kill" on Wednesday. The procedure involves pumping heavy drilling mud into the crippled well in a bid to stop the oil. It's never been tried in 5,000 feet of water.

The oil spill began after the Deepwater Horizon drilling rig exploded last month, killing 11 people. It's the worst spill in U.S. history, dumping between 18 million and 40 million gallons into the Gulf.