|The oil spill has been an economic nightmare for people along the Gulf Coast [GALLO/GETTY]
BP is to conduct one more test as it continues to seal its blown-out well in the Gulf of Mexico before it can declare the well permanently sealed, officials say.
Rich Robson, the offshore installation manager on the Development Driller III vessel, said once the pressure and weight test is finished and officials are confident that the seal will hold permanently, the well will be declared dead.
The 74 barrels of cement that the energy firm pumped into the well on Friday have dried, he said.
Robson said there may be an official announcement that the well has been killed some time on Sunday.
He said that while the declaration will be a significant milestone, 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."
To mark their accomplishment, the crew planned to share a meal of prime rib together, he said.
Once the well is declared dead, it will mark the first time in five months that Gulf Coast residents can be completely assured oil will never spew from the well again.
Worst oil spill
The catastrophe began on April 20, when an explosion 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.
Mud and cement were later 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.
The spill posed major environmental challenges and has been an economic nightmare for people along the Gulf Coast.
With oil still in the water - some of it still washing ashore - fishermen are still fighting the perception that their catch is tainted.
The oil spill, which has brought increased governmental scrutiny of the oil and gas industry, also triggered civil and criminal investigations and cost Tony Hayward, the BP chief, his job.
A costly moratorium on deepwater offshore drilling is still in place as a result of the spill.