BP Plc completed a cement plug at the top of its Macondo well in the Gulf of Mexico, sealing off the source of millions of gallons of oil dumped into the sea after an April drilling-rig explosion.
Cementing the top of the well completes the so-called static kill. The next stage for BP is to finish drilling a relief well that will intercept with the bottom of Macondo to inject cement, according to Bloomberg.
"This is not the end, but it will virtually assure us there will be no chance of oil leaking into the environment," retired Coast Guard Adm. Thad Allen, who oversees the government's spill response, said today.
On Wednesday, crews poured heavy mud down the broken wellhead, pushing the oil back to its underground source -- the first part of the operation.
But the official death knell, according to the government, will come from a "bottom kill," where mud and cement are injected through an 18,000 foot relief well that will intersect with the old well.
This will plug the reservoir 13,000 feet beneath the seabed, bookending the runaway well with impenetrable cement columns hundreds of feet long, ABC News reports.