WASHINGTON -- Three undersea robots worked a mile below the Gulf of Mexico's surface Friday to position a tube inside a leak spewing oil in the gulf. That effort continued as President Barack Obama appeared in the Rose Garden, saying he wouldn't be satisfied until the leak is stopped -- and chastising the oil companies for looking to pass the blame to one another.
Officials said they would know within the next 24 hours whether the latest effort to contain the leak is successful.
"And what really matters is this: There's oil leaking and we need to stop it, and we need to stop it as soon as possible," Obama said.
He accused BP, Transocean and Halliburton of making a "ridiculous spectacle" of finger pointing during congressional hearings earlier in the week.
"The American people could not have been impressed with that display, and I certainly wasn't," he said. "A full investigation will tell us exactly what happened. But it is pretty clear that the system failed, and it failed badly. And for that, there's enough responsibility to go around. And all parties should be willing to accept it."
The federal government is responsible as well, he said, for having too cozy a relationship between the oil companies and the Minerals Management Service, which regulates oil rigs.
"It seems as if permits were too often issued based on little more than assurances of safety from the oil companies. That cannot and will not happen anymore," he said.
Officials for days have been working to cap the leak, which they say is spewing about 210,000 gallons, or 5,000 barrels, of oil into the gulf each day.
But an NPR report Friday questioned that amount, saying their analysis of oil spilling into the gulf finds the spill is far greater than official estimates. NPR findings suggest the BP spill is already far larger than the 1989 Exxon Valdez accident in Alaska.
In that incident, about 250,000 barrels of oil were dumped into Prince William Sound after a tanker crashed.
Up to this point, it is estimated the gulf spill has dumped 4 million gallons, or nearly 100,000 barrels, into the water. That is using a government and BP figure that the spill is dumping 5,000 barrels a day.
A report in the New York Times on Friday citing scientists also questioned that figure.
Coast Guard Commandant Thad Allen said Friday that while there have been different estimates, even if the spewing oil exceeds the 5,000 estimate, "our mobilization is far beyond that," he said. "We haven't been constrained by flow estimates. Ultimately, we'll have to know the extent."
The president noted there have been "varying reports" about how large the leak is, "but since no one can get down there in person, we know there's a level of uncertainty."
Following the reports, Rep. Edward Markey, D-Mass., sent a letter to BP saying the public needs to know how much oil is spewing into the gulf and how much might make it to shore.
"I am concerned that an underestimation of the flow may be impeding the ability to solve the leak and handle management of the disaster. We have already had one estimate that grossly underestimated the amount of oil being released and we cannot afford to have another," he wrote.
BP officials on Friday said while the measurement of 5,000 barrels a day is inexact, it is still the best estimate.
The efforts to mitigate the leak continued Friday on the sea floor, where robots must place a 6-inch wide tube, which is surrounded by a rubber flap, into the leaking 21-inch riser.
The tube is attached to a ship, and if everything goes correctly, the oil will be pumped above. About 85 percent of the spill is pouring from that leak.
The robots are "working under very difficult conditions due to the temperature and pressure and the flow coming out of the pipe itself," said Mark Proegler, a BP spokesman.
Allen said we could know later in the day whether the effort is successful and that BP is continuing to pursue other options to stop the leak before a relief well can be drilled.
The oil slick is "changing in character" Allen said.
"There's good and bad," he said, adding that means shore impacts will be in small bursts.
A final decision is also expected Friday on whether dispersants can be used below the sea to help break up the oil.
A day earlier, lawmakers on Capitol Hill wrangled over the liability limits for oil companies and continued to probe the mishaps and regulatory failures that caused the mammoth spill.
The Interior Department's Minerals Management Service, which regulates oil rigs, came under more scrutiny as congressional investigators scheduled hearings to find out why the federal agency never completed rules that would have required additional controls on blowout preventers -- the safety equipment that failed to stop the spill.
Staffers from the House of Representatives Natural Resources Committee, who traveled to Louisiana this week to sit in on the U.S. Coast Guard-led inquiry into the April 20 explosion of the Deepwater Horizon oil drilling rig, said they learned from the testimony of Mike Saucier, an MMS regional supervisor for field operations, that new rules had been proposed.
Saucier said the agency prepared but never completed regulations in 2001, the first year of George W. Bush's presidency, that would have required secondary control systems for blowout preventers.
"As far as I know, they're still at headquarters," Saucier said.
The devices have been at the heart of the inquiry into what caused the explosion that killed 11.
The House committee also will be examining the agency's ties to the oil industry and whether a cozy relationship kept it from enacting tougher regulations. McClatchy Newspapers reported last week that nearly 100 standards set by the American Petroleum Institute are included in the MMS' offshore operating regulations.
The chairman of the committee, Rep. Nick Rahall, D-W.VA., asked the MMS on Thursday to provide all documents related to regulations that it proposed but never finalized. He also asked the agency to turn over inspection reports from the oil rig and a list that details potential noncompliance with MMS regulations.
Meanwhile, efforts on Capitol Hill to raise the liability cap for oil companies from $75 million to $10 billion ran into a roadblock when Sen. Lisa Murkowski, R-Alaska, objected to the proposal.
Murkowski said she supports lifting the cap, but contended the $10 billion figure would prevent smaller, independent companies from drilling on the Outer Continental Shelf.
Sen. Bob Menendez, D-N.J., mocked the idea of independent companies as "mom and pop" oil companies and questioned why smaller companies shouldn't be held responsible in the event of a catastrophe. "Ten billion dollars is a drop in the bucket," Menendez said, noting that BP, the owner of the runaway well, posted profits of more than $5 billion for the first quarter of 2010.
Menendez said that he and other lawmakers plan to try to push the bill again.
"We're going to see who stands with the average citizen, community, fishermen and others and who stands with Big Oil," he said.
Six West Coast senators and a Florida congresswoman also introduced separate bills that together would have the effect of banning offshore drilling permanently.
The legislation by U.S. Rep. Corrine Brown, D-Fla., would permanently prohibit offshore drilling on the outer Continental Shelf of the Atlantic Ocean and Gulf of Mexico. The bill by Democratic Sens. Barbara Boxer and Dianne Feinstein of California, Jeff Merkley and Ron Wyden of Oregon and Maria Cantwell and Patty Murray of Washington would permanently ban oil and gas drilling off the California, Oregon and Washington coasts.
While the political storm over the spill gathered steam, BP engineers said their best chance to control the underwater oil leak now rests with the tube.
If the tube fails, then BP officials have a back-up plan: lower a steel and concrete dome called a "top hat" over the leak. The top hat -- four feet in diameter and five feet tall -- would be attached to a drill pipe that
would siphon the oil to a ship at the surface.
The "top hat" has been resting on the sea floor since Tuesday and originally was planned as BP's next attempt to control the spill. There was no explanation for why BP engineers decided to try the insertion tube first.
On Thursday, BP estimated that it has spent about $450 million on fighting the oil spill and drilling a relief well since the Deepwater Horizon exploded. That's $100 million more than estimates released earlier in the week.
Meanwhile, Transocean, the Switzerland-based offshore contractor that owned the Deepwater Horizon, filed a petition in federal court in Houston seeking to limit the company's liability from the oil spill to less than $27 million.
Invoking a little-known 1851 maritime law, the company said it shouldn't have to pay more than the salvage value of the charred oil rig and its freight, all of which sank in 5,000 feet of water. Before the accident, the rig was valued at more than $500 million.
In a statement, Transocean said the court petition was filed at the request of its insurance companies, and the petition will allow the company to consolidate more than 100 current lawsuits before a single federal judge in Houston.
Lawyers for those injured in the blast said the petition could also prevent any claims filed more than six months after the accident.
"It's very unfair," said Matthew Shaffer, a Houston attorney who represents a handful of Transocean employees injured in the blast. "It's a slap in the face to anyone who has been injured because of their negligence."
Along the Gulf Coast, state officials noted additional reports of oil washing ashore amid a growing chorus of concern over the massive use of chemical dispersants to break up the oil.
The Coast Guard said that tar balls were found at South Pass, La., at the mouth of the Mississippi River, and on the southern end of the Chandeleur Islands east of New Orleans. More tar balls were found on Whiskey Island off the Louisiana coast, the farthest point west where oil has been seen so far.
At a town hall meeting in Port Sulphur, La., dozens of local residents were angry over the hundreds of thousands of gallons of chemical dispersants.
Asked Kindra Arneson, whose husband is a fisherman: "How much of this stuff, this dispersant, the toxins from the oil spill itself and everything, is evaporating up into the air, coming onto our shores, pouring down onto our land?"Murkowski under fire for position on spill liability cap
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By ERIKA BOLSTAD, LESLEY CLARK, DANIEL CHANG and JENNIFER LEBOVICH