Reporting from Houston; Cocodrie, La.; and Atlanta — Engineers hoping to contain oil gushing from the mangled pipe beneath the Gulf of Mexico appeared to make important headway Sunday, as robot submarines jammed a suction tube into the pipe in an attempt to coax the oil to a ship on the surface.
Officials for the oil company BP said they could not estimate how much oil and gas was flowing through the tube, nor what percentage of the leak was being contained, until Monday or Tuesday at earliest. They originally said the plan might suck up as much as 75% of the leaking oil.
Without the number of gallons retrieved, it remained unclear Sunday whether the nation's brightest minds would be capable of solving an engineering conundrum that is spewing 210,000 gallons of oil a day, and perhaps more, into the gulf waters from a canyon 5,000 feet below the sea.
Although relatively little oil has washed up on land so far, scientists are growing worried about the effects of massive plumes of oil hovering below the surface in areas teeming with life, including plankton, turtles, dolphins and whales.
Interior Secretary Ken Salazar and Homeland Security Secretary Janet Napolitano warned in a statement Sunday that the latest in a series of short-term attempts at stopping the leak was "not a solution, and it is not clear how successful it may be."
In recent days, the Obama administration has assembled a "dream team" of scientists to deal with the leak, including experts in robotics, physics, X-ray technology and the hydrogen bomb. Energy Secretary Steven Chu, a physicist who won the Nobel Prize, met with BP engineers in Houston last week and promised that the "intellectual horsepower of the country is engaged in solving this problem."
But unlike many science and engineering problems that can be worked out in a lab or on a blackboard, this one is unfolding far from the reach of a human hand, in real time, with a potentially high penalty for failure.
"It's not just theory. It's reality that has to be dealt with," said Henry Petroski, a Duke University professor of civil engineers and history. "This is a really tough problem."
The leak was triggered April 20 by a blowout of a BP well that caused an explosion on the Deepwater Horizon, a mobile oil rig that had just finished drilling an 18,000-foot hole about 48 miles off Louisiana. The accident killed 11 workers, and the $600-million rig now lies at the bottom of the sea.
BP's engineers first focused on using robot submarines to shut off the blowout preventer, an apparatus that had failed to sever or plug the well pipe. More recently, a 100-ton box lowered over the leak in an attempt to siphon it to the surface failed when icy gas crystals, hydrates, clogged it.
This weekend's plan involved running a long suction tube from a ship to the damaged riser pipe on the ocean floor. A 4-inch-wide insertion tube was guided into the 21-inch-wide riser, which also was plugged with rubber diaphragms.
If all goes as planned, a flow of nitrogen in the tube will lift the oil to the ship. Methanol will be added to help prevent the formation of hydrates, and heated seawater will promote the flow of oil.
At a Houston news conference, company leaders said they first inserted the tube about midnight Saturday. It operated for four hours and was just beginning to bring oil to the surface ship when an undersea robot knocked the tube loose. Engineers reinstalled the tube a few hours later.
BP officials said the flow rate was slowly increasing. But they couldn't say how much they had collected. "I don't have any idea at this point," said Kent Wells, BP's senior vice president for exploration and production.
Even if successful, BP must also contain a second leak on the ocean floor.
The huge and growing stain of oil continues to hover in and around the shores and inlets of Alabama, Louisiana and Mississippi. The latest oil landfall was reported at Grand Isle, La., where a number of tar balls washed ashore, said Coast Guard Petty Officer Erik Swanson.
At the same time, scientists have begun measuring the vast quantities of oil hidden to the human eye. Vernon Asper, an oceanographer and marine professor at the University of Southern Mississippi, was part of a group that landed at Cocodrie, La., on Sunday, after completing a two-week research trip in the gulf. Asper said they documented plumes of oil 2,000 to 6,000 feet below the water's surface, covering an area 4 miles wide and 15 miles long.
Bacteria in the water naturally break down oil, but that process sucks up large amounts of oxygen. Such a scenario could cause dead zones similar to a seasonal one caused by nitrogen-rich runoff down the Mississippi River.
"We're concerned about that, because everything that lives down there at these depths in the water needs oxygen, so if you use up all the oxygen they're going to be impacted," said Ralph Portier, an environmental science professor at Louisiana State University.