A 100-TON concrete containment structure known as a cofferdam was yesterday towed to the site in the Gulf of Mexico where BP’s Deepwater Horizon oil rig exploded and sank on April 20th.
A crane was transported on a separate ship, and work was to begin yesterday afternoon to lower the cofferdam onto the oil pipe that is spewing some 210,000 gallons of petrol into the Gulf daily.
BP said the procedure could take until Monday and, if successful, could stop the leak. Oil from the well would be siphoned through steel hoses to a tanker on the surface, until a more permanent solution is reached.
BP is drilling a nearby relief well that should be able to permanently plug the leaking well about three months from now.
The cofferdam strategy has never been attempted at such depths. The operation is complicated by high pressure and cold temperatures 1,500m below the surface.
“I know we are all hoping that this containment system will work, but I want to remind everybody that this is a first of its kind deployed in 5,000ft of water,” said Rear Admiral Mary Landry, of the US coast guard.
Earlier this week, BP capped the smallest of three leaks in the pipe. Underwater robots installed a valve but the same volume of crude oil is still escaping from two other holes.
In a congressional hearing on Tuesday, BP executives warned that if the cofferdam fails, the leak could worsen and gush more than 10 times the present amount, that is to say 2.5 million gallons a day.
Meanwhile, the first confirmed reports of oil making landfall were received from Freemason’s Island, in the Chandeleur island chain off the east coast of Louisiana.
The islands are part of the Breton wildlife refuge, which is home to the endangered brown pelican, the least tern and piping plover.
There are now 2,000 people working to contain the oil spill with booms and dispersants. “If we’re lucky, we’ll recover and intercept something like 10 per cent of it,” said Prof Ian McDonald of Florida State University. “We’re not going to stop much of it.”
BP has already used 150,000 gallons of dispersants, which also have negative environmental effects.
The spill has transformed the debate about offshore drilling in the US. Governors Arnold Schwarzenegger of California and Charlie Crist of Florida, both Republicans, have said they will oppose drilling off the shores of their states.
President Barack Obama announced new offshore drilling plans in March.
“You turn on television and you see this enormous disaster, and you say to yourself, ‘Why would we want to take that risk?’” Schwarzenegger said.
But Louisiana, the state which stands to lose the most from this spill, calls only for stronger regulation of the oil industry, and not a stop to offshore drilling.
It emerged this week that the Mineral Management Service, part of the US Department of the Interior, last year granted BP an exemption from a requirement for an environmental impact study for the Deepwater Horizon well, on the grounds that a massive spill was highly unlikely. Eleven days before the rig exploded, BP lobbied for further exemptions.