The Obama administration today said BP's efforts to contain the oil leak in the Gulf of Mexico are working, but that the next few days will be critical in determining the success of the "top kill" procedure.
BP CEO Tony Hayward said on "Good Morning America" today that the cleanup operation along the Gulf coast is "going pretty well," an assessment echoed by Coast Guard Adm. Thad Allen, who is overseeing the Obama administration's response to last month's oil spill.
"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," Allen said. "The challenge will be to get enough down there to overwhelm the pressure that's pushing the oil up."
BP's "top kill" procedure entails putting mud on the leak to stop the oil from flowing up.
Allen said the challenge will be to put enough pressure on the mud to keep the organic compounds from coming up.
"They have been able to stop the hydrocarbons from coming up the wellbore," he told "GMA's" George Stephanopoulos. "I think the real challenge today is going to be sustain the mud on top of the hydrocarbons and reduce the pressure to the point where they could actually put a cement plug in."
Allen said the next 12 to 18 hours will be "very critical" and the real question will be whether they can sustain this effort to stop the oil from gushing into the ocean.
Hayward said BP has also been pumping rubber and other material into the well, 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 will be at least another 48 hours "before we can have confidence that we've succeeded."
The Obama administration -- the president in particular -- has taken heat for the perception that it didn't pressure BP enough early on. 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.
Former Alaska Gov. Sarah Palin said Thursday the response represents a culture of "buck passing" in the Obama administration, a charge that the Coast Guard's Allen denied.
"I don't believe the federal effort has caused this disaster," Allen countered. "The issue is it's one of the most anomalous and unprecedented events we've encountered because there's no human access at the source of the leak and human technology to deal with that source lies in the hands of the private sector."
BP has said the "top kill" procedure, which is being shown on a live video feed to the public, is the best shot at stopping the spill.
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.
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.
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 AC Cooper told ABC News.
Some locals have blamed the Obama administration for responding too slowly, and putting its boot on BP's neck too late in the game.
"I think President Obama is going to have to take control of this situation and let the federal government take over the clean-up and let BP and their 'expertise' to do the blowout," said Clint Guidry, director of the Louisiana Shrimpers Association.
Allen said the government hired local fishermen to help with the cleanup and also to provide them with job opportunities. He said toxicologists are looking at what might be behind the fishermen's sickness, including food sources. But environmentalists say more needs to be done in ensuring the health of local fishermen.
"We as the public have a right to know and fisherman need to not have to chose between putting a meal on the table and their own health," said Miriam Rotkin-Ellman of the environmental group Natural Resources Defense Council. "Some of the fisherman have come to work with their own protection and told they are not allowed to wear it on the job."
Obama will visit the Gulf coast today, his second trip to the region since the leak began last month. White House officials say the purpose of his trip is to hear from local officials and other individuals at the scene and see what ideas they have about containing the oil spill.
The president is also visiting the region in the hopes of convincing locals that he is on the case and that the federal government is doing everything it can to contain the disaster.
The president held a nearly hour-long news conference Thursday to announce that planned oil exploration in the Gulf coast and off the Atlantic Coast will be cancelled and a six-month moratorium will be placed on new, deepwater drilling permits.
The president also pushed back against critics who say the federal government didn't act quickly enough.
"Those who think that we were either slow on our response or lacked urgency don't know the facts," Obama said. "This has been our highest priority since this crisis occurred."
At the same time, he also took responsibility, saying the federal government is in charge of containing the oil spill, not BP.
"I take responsibility," he said."It is my job to make sure that everything is done to shut this down."
A USA Today/Gallup poll released Thursday showed that 6 in 10 Americans say the government is doing a "poor" job on the oil spill.
Democratic lawmakers from the region say too little is being done to contain the worst ecological disaster caused by an oil spill in U.S. history.
"Everything that I know and love is at risk," an emotional Rep. Charlie Melancon, D-La., said Thursday. "Even though this marsh lies along coastal Louisiana, these are America's wetlands."
Plaquemines Parish president Billy Nungesser has been a vocal critic of the federal government's response to the oil disaster, even calling Allen a "national embarrassment."
"I want him [Obama] to say that they're doing everything physically possible to keep this oil from destroying our wetlands," Nungesser, who is based in Venice, Louisiana, said on "GMA" today. "That's all we've been asking for from the beginning.
"I don't think the president knew what was really going on."
ABC News' Jake Tapper and Karen Travers contributed to this report.