U.S. President Barack Obama is expected to establish a commission to investigate the oil spill in the Gulf of Mexico.

Created by executive order, it will be similar to panels that looked into the space shuttle Challenger disaster and the nuclear accident at Three Mile Island, according to a White House official who spoke on condition of anonymity ahead of a public announcement.

No current government employee or elected official will be eligible to serve on the commission, the official said. Other details weren't immediately available.

In the first casualty of the crisis, Chris Oynes, who oversees offshore drilling programs at the Minerals Management Service at the Interior Department, will retire at the end of the month, according to an email from the agency.

Oynes has come under criticism for being too close to the industry the agency oversees. His departure comes as Obama has vowed to end a "cozy relationship" between the MMS and industry.

A BP diagram shows how the Riser Insertion Tube Tool is to be positioned within the leaking pipe 1,500 metres below the water's surface in the Gulf of Mexico. (BP)

Meanwhile, a newly installed pipe drawing oil from a broken pipe on the floor of the Gulf of Mexico to a tanker on the surface is helping to contain the catastrophic oil spill, but is "not a solution to the problem," U.S. officials say.

BP installed the Riser Insertion Tube Tool (RITT) successfully on Sunday morning after a failed attempt on Saturday evening.

Since then, it has captured the oil and gas spewing out of the broken underwater pipe at a rate of about 191,000 litres a day and drawn it to the surface 1,500 metres above, BP chief operating officer Doug Suttles said Monday. That's a fraction of the 800,000 litres believed to be gushing out of it daily.

"This technique is not a solution to the problem, and it is not yet clear how successful it may be," Interior Secretary Ken Salazar and Homeland Security Secretary Janet Napolitano said in a joint release Sunday.

"We will not rest until BP permanently seals the wellhead, the spill is cleaned up, and the communities and natural resources of the Gulf Coast are restored and made whole," they said.

Reefs at risk

Those natural resources are facing a new danger: scientists say the spill has spewed columns of oil over ecologically sensitive reefs and that two powerful Gulf currents will carry the oil to other reefs.

Computer models show the oil may have already seeped into a powerful water stream known as the loop current, which could propel it into the Atlantic Ocean, according to William Hogarth, dean of the University of South Florida's College of Marine Science.

Scientists have used this image of oil gushing from the broken riser pipe connected to the well to suggest more than 800,000 litres daily is spewing into the Gulf of Mexico. (BP)

That could bring it to the Florida Keys, about 725 kilometres away.

"This can't be passed off as 'it's not going to be a problem,'" said Hogarth. "This is a very sensitive area. We are concerned with what happens in the Florida Keys."

A second current could move the oil as far west as central Texas.

The models are based on weather, ocean current and spill data from the U.S. navy and the National Oceanic and Atmospheric Administration, among other sources.

BP has deployed almost three million litres of chemical dispersants to break down the oil.

Marine scientists say dispersing and sinking the oil helps protect the surface species and the Gulf Coast shoreline but increases the chance of harming deep-sea reefs, which are seen as bellwethers for sea health.

Ramping up

BP had previously said the tube, if successful, was expected to collect most of the oil that has been gushing from the well since a drilling rig it had leased, the Deepwater Horizon, exploded on April 20 and sank.

Underwater robots inserted the tube, 10 centimetres in diameter, into the end of the 53-centimetre-wide busted riser pipe most recently on Sunday. Rubber flaps on the tube are meant to form a seal around it to keep oil from gushing out around it.

Crews will slowly ramp up how much it funnels over the next few days. They need to move slowly because they don't want too much frigid seawater entering the pipe.

That seawater could combine with gases to form the same ice-like crystals that doomed a previous containment effort just over a week ago.

With files from The Associated Press