Oil is no longer spewing into the Gulf of Mexico, at least temporarily, as BP said it choked off the flow from its undersea well that ruptured in April and caused the worst offshore oil spill in United States history.
It is the first time the flow has stopped since an explosion on the Deepwater Horizon rig on 20 April. The well has been sealed with a cap as part of a test of its integrity that could last up to 48 hours.
Â â€œI think that it is a positive sign,” said U.S. President Barack Obama, whose public approval ratings fell as the oil spill crisis dragged on.
He however cautioned that “we’re still in the testing phase.”
BP executive Kent Wells said the oil had been stopped at 14:25 hours local time (1925 GMT) and he was “excited” by the progress.
“It is very good to see no oil go into the Gulf of Mexico,” said Mr Wells.
BP shares rose in New York trading on Thursday after the flow was stopped, having already performed well over the day.
However, BP is stressing that even if no oil escapes for 48 hours, that will not mean the flow of oil and gas has been stopped permanently.
BP Chief Operating Officer, Doug Suttles emphasised that there was no reason for “celebration” yet, particularly for those in areas already damaged by oil.
“The job is not finished,” he said.
The pressure testing is necessary to check the strength of the well.
If the pressure within the cap on top is low, that could indicate oil is leaking out further down the well.
If the pressure remains high, BP and the government will have to decide whether to try to keep the well shut or to leave it open and pipe oil to four vessels on the surface.
The US government’s incident commander, Admiral Thad Allen, said even if it was successful, the well would be re-opened and oil capture by ships on the surface would restart while a seismic test was done.
“We can go back then and put the system under pressure again.
â€œOnce we are convinced we can certainly consider shutting in the well, that is always possible and we would certainly look to do that,” said Admiral Allen.
He emphasised that the option of shutting in the well – closing all the valves and stopping the flow – was a “side benefit” of the new capping stack.
After three months of many failed attempts, people are sceptical and at the same time the mood has brightened considerably, because this oil spill has had a deadening psychological effect on the Gulf Coast.
The long-term plan is still to dig a relief well which will intercept the leaking one.
People have just left this coastline, tourists in particular, because they don’t want to run the risk of having a vacation ruined by oil.
Meanwhile, BP continues to face political pressure in the US.
A congressional committee has agreed measures that would ban the firm from new offshore drilling for seven years.