May 17, 2010 -- President Obama announced today that he will create a presidential commision to investigate the oil spill in the Gulf of Mexico, an administration official said.

The commission, said to be similar to those that probed into the space shuttle Challenger disaster and the Three Mile Island nuclear accident, will examine the oil industry's practices, such as rig safety.

It will also examine the government's response and study the "structure and function" of government agencies like the embattled U.S. Mineral Management Service.

Current government officials or elected officials would not be eligible to serve on the commission.

On Capitol Hill, Congress is also promising more scrutiny of the government's response to the BP spill.

The Senate Homeland Security committee today began questioning government officials, including Homeland Security Secretary Janet Napolitano and Interior Secretary Ken Salazar about their agences' actions.

Sen. Barbara Boxer and other Senate Democrats called today for the Department of Justice to open a criminal and civil investigation into the spill.

There are already signs that the increased scrutiny is having an effect.

An administration official confirmed to ABC News today that an Interior Department official will step down in the wake of the spill. Chris Oynes, who oversaw offshore oil and gas drilling in the Gulf of Mexico for the Minerals Management Service is said to be "retiring" from his position as associate director at the end of the month.

BP Claims Some Success in Capturing Oil

While news of the investigation broke in Washington, BP said today that, for the first time, one of its schemes to capture oil from the leak is actually working.

Remote submersibles hooked up a mile-long tube to the broken well pipe over the weekend. BP says it is siphoning some of the leaking oil to a tanker on the surface, which will eventually be processed and sold like other crude.

It can be called a partial success at best. The tube doesn't stop the gushing oil, but slows it, according to the company. BP says that over time, they may be able to stop up to 80 percent of the oil.

"We've got flow going, it is great progress over the last 24 hours. What we are doing is slowing, doing something called opening up the choke at the top of well to slowly increase the flow rates," Bob Dudley, BP's managing director who is overseeing the response efforts, said on "GMA."

This morning, BP said the tube was suctioning about 1,000 barrels of oil a day, or about 20 percent of what BP estimates is leaking from the well, according to The Associated Press.

Others call the plan wildly optimistic.

"I don't think it's realistic that they're going to get a significant fraction of the leak into the containment vessel," said Steve Wereley, professor of fluid mechanics at Purdue University. "Plugging the 4-inch pipe into the 20-inch pipe, that area is going to leak.

To address that concern, BP has surrounded the straw with a series of rubber stoppers to create a seal.

BP is also pursuing two other methods of stopping the oil. Today, the company started drilling a second relief well, and at the end of the week, BP may turn to the "top kill" strategy, where concrete and mud would be shot into the leak to plug it.

"We've got an engineering operation where we will enter the blowout preventer at the well head and be able to inject some heavy fluids to be able to try to permanently stop the flow from the well," Dudley said. "In addition to that we are still drilling the relief well."

BP Will Reimburse 'All Legitimate Claims'

Over the weekend Napolitano and Salazar sent a letter to BP that stated: "We understand that BP will not in any way seek to rely on the potential $75 million statutory cap to refuse to provide compensation to any individuals or others harmed by the oil spill even if more than $75 million is required and BP will not seek reimbursement from the American taxpayers."

BP Will Reimburse 'All Legitimate Claims'

This morning Dudley said the $75 million cap was irrelevant and BP "will pay all legitimate claims."

"We've said from day one we will take responsibility for the spill, we will not hide behind the $75 million cap. We are taking responsibility for the spill not just in words, we've set up claims centers across the Gulf Coast," Dudley said. "We are issuing checks to those who have been affected in the fishing area so they don't miss a boat payment or a house payment [and can] put food on the table. I think we are seeing not only our agreement with that as well as our actions."

Plumes of Oil Discovered Underwater

Scientists discovered disturbing findings under the sea -- huge plumes of oil, some of which are 10 miles long and three miles wide. These plumes may explain why the oil slick hasn't grown on the surface.

"This oil as you can see has depth, it's not only the size of Manhattan in area, but it's also several hundred meters depth," University of Southern Mississippi professor of geological oceanography Vernon Asper said.

Rep. Edward Markey Lashes Out at BP

On Sunday, Rep. Edward Markey, a Democrat from Massachusetts, lashed out at BP and accused the company of "burying its head in the sand on these underwater threats" and compared the underwater plumes to "hidden mushroom clouds."

In response to Markey's statement, Dudley said the joint incident command will investigate the plumes, but "as of today, it is hard to even comment on them."

But some scientists say these plumes are not huge "mushroom clouds" under the sea. In fact, they are not visible to the human eye. What they detected were dips in the oxygen level of the water between 2,000-6,000 feet. Microbes are feasting on the oil, and that frenzied meal is causing them to consume oxygen as well, but the scientists say that so far not at dangerous levels.

The biologists says they are pleased with the way the bacteria are devouring the oil in the deep, and are beginning to question the wisdom of using dispersants at the source of the leak, because that might interrupt that bacterial smorgasbord.

BP and the Coast Guard, however, have been saying that dispersants are the reason more oil has not been seen rising to the surface.

When asked if the chemical dispersants were making the situation in the Gulf worse by depleting the oxygen, Dudley said the dispersants are like "soap suds."

"It is like soap that breaks up the oil into small, very small droplets and then it degrades, biodegrades. And that's part of the natural process of it," Dudley said. "And so what will happen then is a little of the oxygen will be reduced, that means the bacteria is working. We think we see the natural processes at work here through the use of dispersants."

ABC's Sunlen Miller, Reuters and The Associated Press contributed to this report.