President Barack Obama returns to the Gulf of Mexico coast Friday, insisting he's in charge of efforts to shut down what is now estimated as the worst oil spill in U.S. history.
Still Obama has admitted the U.S. government doesn't have the technology or expertise and must rely on oil giant BP. It could be late Friday or over the weekend before BP knows if its latest experimental effort has succeeded in stopping the undersea gusher of oil.
Obama was to attend a briefing Friday at the U.S. Coast Guard Station in Grand Isle, La., by Adm. Thad Allen, who is overseeing the response to the spill. It would be his second visit to the region since the disaster began with an April 20 explosion at the drilling rig Deepwater Horizon that killed 11 workers.
Obama seized ownership Thursday of what he called a "tremendous catastrophe," after weeks of loveallowing Cabinet members take the public lead as the crippled BP PLC well spewed millions of gallons (liters) of crude oil into the Gulf from nearly a mile (1,500 meters) below the surface.
"I take responsibility. It is my job to make sure that everything is done to shut this down," Obama declared at a White House news conference dominated by the spill.
For everyone, the stakes grew even higher Thursday as government scientists said the oil has been flowing at a rate 2 1/2 to five times higher than what BP and the U.S. Coast Guard initially estimated.
Two teams of scientists calculated the well has been spewing between 504,000 gallons (1.9 million liters) and more than 1 million gallons (3.8 million liters) a day. Even using the most conservative estimate, that means about 18 million gallons (68 million liters) have spilled so far. In the worst-case scenario, 39 million gallons (148 million liters) have leaked.
Even at the lowest estimate, the Gulf spill has far surpassed the size of the previous largest U.S. oil spill, the 1989 Exxon Valdez disaster, in which a tanker ran aground in Alaska, spilling nearly 11 million gallons (42 million liters).
BP PLC insisted its "top kill" attempt to plug the gusher was progressing as planned, though the company acknowledged drilling mud was escaping from the broken pipe along with the leaking crude.
"The fact that we had a bunch of mud going up the riser isn't ideal but it's not necessarily indicative of a problem," spokesman Tom Mueller said.
Early Thursday, officials said the process was going well, but later in the day they announced pumping had been suspended 16 hours earlier. BP did not characterize the suspension as a setback, and Eric Smith, associate director of the Tulane Energy Institute, said the move did not indicate the top kill had failed.
"The good news is that they pumped in up to 65 barrels a minute and the thing didn't blow apart," Smith said. "It's taken the most pressure it needs to see and it's held together."
A top kill has never been attempted before so deep underwater. If the procedure works, BP will inject cement into the well to seal it permanently. If it doesn't, the company has a number of backup plans. Either way, crews will continue to drill two relief wells, considered the only surefire way to stop the leak.
In another troubling discovery, marine scientists said they have spotted a huge new plume of what they believe to be oil deep beneath the Gulf, stretching 22 miles (35 kilometers) from the leaking well head northeast toward Mobile Bay, Alabama. They fear it could have resulted from using chemicals a mile below the surface to break up the oil.
Obama, meanwhile, has been under mounting criticism _ even from members of his own Democratic Party _ for seeming aloof to what could be the biggest environmental tragedy in U.S. history.
Asked about inevitable comparisons between his administration's handling of the disaster with his predecessor's response to Hurricane Katrina in 2005, which flooded New Orleans and other areas, Obama said: "I'll leave it to you guys to make those comparisons. ... What I'm thinking about is how do you solve the problem?"
Comparisons to former President George W. Bush's paltry response to the devastating storm have come mainly from opposition Republicans.
"I'm confident people are going to look back and say this administration was on top of what was an unprecedented crisis," he said. "We've got to get it right."
Obama is struggling for high ground in the political wars raging in the months before the November congressional elections, where his Democratic majorities in both House and Senate are in danger.
He has passed through bruising legislative sessions and took a notable battering from Republicans as he pushed through health care overhaul. Now he's struggling to keep congressional Democrats focused on financial regulatory reform while trying to smooth the Senate confirmation of his second Supreme Court nominee.
The president, who campaigned on a promise to change the way Washington does business, blasted a "scandalously close relationship" he said has persisted between Big Oil and government regulators.
Conceding that "people are going to be frustrated" until the well is capped, Obama said he would use the full force of the federal government to extract damages from BP.
"We will demand they pay every dime they owe for the damage they've done and the painful losses they've caused," Obama said.
He spoke shortly after the head of the troubled agency that oversees offshore drilling resigned under pressure. The departure of Minerals Management Service Director Elizabeth Birnbaum was announced just before Obama's news conference began.
While making clear he was leading the response, Obama acknowledged some things could have been better handled.
He said his administration didn't act with "sufficient urgency" prior to the spill to clean up the Minerals Management Service, accused of corruption and poor regulation of drilling rigs and wells.
While Obama defended calling for an expansion of offshore drilling prior to the spill, he said he "was wrong" to believe that oil companies were prepared to respond to worst-case oil spills.
Obama also said the administration took too long to make its own measurements of the size of the spill, and didn't push BP hard enough early on to release underwater footage of the gusher.