BP has conducted one more test before declaring the well permanently sealed, officials say. (photo, from bbcimg.co.uk)
The pressure test showed a cement plug put in place by BP to permanently “kill” the well was holding.
Officials are now confident that the seal will hold permanently, explained Rich Robson, the offshore installation manager on the Development Driller III vessel.
He added that the 74 barrels of cement that the energy firm pumped into the well on Friday have dried.
While the declaration is a significant milestone, Robson said it would be difficult to celebrate too much given the tragedy of the oil spill.
“It’s kind of bittersweet because we lost 11 men out here,” he said.
“There isn’t going to be any real celebration. To a lot of people, the water out here is a cemetery.”
In order to mark their accomplishment, the crew planned to share a meal of prime rib together, he said.
Now that the well has been declared dead, it is the first time in five months that Gulf Coast residents can be completely assured oil will never spew from the well again.
On April 20, the catastrophe began by an explosion that killed 11 workers, sank a drilling rig and led to the worst offshore oil spill in the US history.
The Gulf well spewed 206 million gallons (780 million litres) of oil before the gusher was first stopped in mid-July with a temporary cap.
Later mud and cement were pushed down through the top of the well, allowing the cap to be removed.
BP is a majority owner of the well and was leasing the rig from owner Transocean Ltd.
On top of the major environmental challenges, the spill has been an economic nightmare for people along the Gulf Coast.
But fishermen are still fighting the perception that their catch is tainted because there is still oil in the water, some of it is still washing ashore.
The oil spill has brought increased governmental scrutiny of the oil and gas industry. But it also triggered civil and criminal investigations and cost Tony Hayward, the BP chief, his job.
As a result of the spill, a costly moratorium on deepwater offshore drilling is still in place.