BP has finally started tests on a new cap designed to temporarily fix its leaking oil well in the Gulf of Mexico.
The government previously delayed the testing, citing that more analysis was needed on the plan.
The tighter-fitting cap was lowered over the blown-out well Monday night and is designed to be a temporary fix until the well is plugged underground.
Kent Wells, a senior vice president at BP, said Wednesday that the valve on the top portion of the cap was shut and oil had stopped pouring out from there.
He added that crews began working late that evening to shut off the other two valves and completley close the oil in, but that the process will take hours.
If the fix works, the cap will hold all the oil inside the well machinery like a stopper. But if the pressure is too strong to shut down the well, the cap can still be used to channel oil through pipes to collection ships.
Officials stress there are no guarantees and urge patience from Gulf residents.
"The oil recovery and the impacts of this oil will probably extend well into the fall, in terms of oil coming ashore, tar balls, beach cleanup," said U.S. National Incident Commander Thad Allen.