Engineers struggle to plug source of oil spill

Using remote-controlled submarines to shut off the leaking oil well in the Gulf of Mexico is like doing "open heart surgery at 5,000 feet in the dark," the head of BP's US operations said yesterday.

BP America Chairman and President Lamar McKay acknowledged that the oil gushing from the fractured well nearly a mile (1,500 metres) below the ocean surface was due to a defective equipment designed to shut down the well in a blowout.

Six robotic submarines struggled to activate a 450-tonne blowout preventer valve that failed to work properly when the well exploded April 20, igniting a fire that sent the Deepwater Horizon rig to the ocean floor with 11 workers missing and presumed dead.

British oil giant BP, which owns the well, is "still working hard" on fixing the valve, Mr McKay said on ABC's "This Week" news show.

"As you can imagine, this is like doing open heart surgery at 5,000 feet in the dark with robot-controlled submarines," Mr McKay told ABC.

The well is gushing an estimated 200,000 gallons of crude a day and has produced a slick more than 200 kilometres long that is threatening an environmental and economic catastrophe on the coast of Louisiana and other southern US states.

"Everything is done remotely, including the inspection of the pipeline, the survey and the repair of the hydraulic systems associated with the blowout preventer," said Interior Secretary Ken Salazar, speaking on CNN'S "State of the Union" programme.

"The highest technology is being applied," he said.

Mr Salazar was clear on the source of the problem. "There is no doubt at all that what has happened is that the blowout prevention mechanism at the bottom of the well is defective," he said.

"Our job is basically to keep the boot on the neck of British Petroleum to carry out the responsibilities that they have under the law and contractually to move forward and stop this spill."