The president today sought to reassure residents and urged patience. He also defended the administration's moves and called for unity on solving the crisis.
"Not every judgment we make is going to be right the first time out," Obama said. "There are going to be disagreements... There are not going to be silver bullets."
The spilling crude oil has destroyed sea life and wildlife and has been designated the worst oil spill in U.S. history, based on new estimates of the oil flow released Thursday by a government task force. Scientists say the mile-deep well has been spewing between 12,000 and 19,000 barrels of oil a day, an estimate far worse than previously estimates.
Meanwhile, another huge underwater plume has been found south of Mobile, Alabama. Marine scientists say it may be 20 miles long and several miles wide.
The Obama administration says the next 12 to 18 hours will be critical in examining whether BP can sustain this effort to stop the oil from gushing into the ocean.
"They've demonstrated they can do something that actually has never been done before, that's actually apply this mud 5,000 feet below the surface," Coast Guard Adm. Thad Allen, who is overseeing the Obama administration's response to last month's oil spill, said on "Good Morning America" today. "The challenge will be to get enough down there to overwhelm the pressure that's pushing the oil up."
BP CEO Tony Hayward said on "GMA" today that BP has also been pumping rubber and other material into the well in a process known as "junk shot," and that they will continue to pump more mud today.
"The operation is continuing, it's going pretty well, according to plan," Hayward said. "As everyone appreciates, this has never been done in 5,000 feet of seawater, so we've proven the technology, and we are learning about how to optimize the technology."
But Hayward added it won't be until Sunday "before we can have confidence that we've succeeded."
The "top kill" procedure, which is being shown on a live video feed to the public, is the best shot at stopping the spill, BP officials have said.
The engineers behind the effort to plug the oil leak were worried that too much of the drill mud was pouring out, so they stopped piping it down unexpectedly early Thursday morning to the broken blowout preventer 5,000 feet below sea level.
Technicians turned the pumps back on Thursday evening and resumed the process of trying to jam the leaking well on the sea floor. Through the night, a 30,000-horsepower engine shot drill mud down two narrow tubes in an effort to stop the leaking oil once and for all.
If the drill mud can plug the leaking well, engineers will then cap it with cement.
Fishermen in the region are apparently getting sick because of the tainted waters. At least seven fishermen working to clean the spill for BP were hospitalized Wednesday and dozens of others have complained of similar symptoms after inhaling the noxious fumes: nausea, headaches, and dizziness.
"I'm mad as hell. I want everyone to know that. If they [the federal government] want a bigger role they can do that," fisherman A.C. Cooper told ABC News.