Obama flies to Louisiana as fears grow over oil-spill disaster

President Barack Obama took a first-hand look at the response effort at the southern tip of Louisiana as oil from a leaking BP well continued to spew into the Gulf of Mexico, declaring that the British energy giant retained primary responsibility for meeting the crisis – and footing the cost.

Caught under a rain squall, Mr Obama called the spill a "massive and potentially unprecedented environmental disaster". And he was blunt in placing the burden of blame. "BP is responsible for this leak. BP will be paying the bill," he said, before adding: "But as President of the United States I am going to spare no effort to respond to this crisis."

Earlier the chairman of BP, the London-based oil company which was operating the rig that exploded and crumpled nearly 50 miles out to sea almost two weeks ago, said a "failed piece of equipment" may have been to blame. He also equated efforts to plug the leak at a depth of almost a mile to "open heart surgery".

Even as Mr Obama arrived in Venice, calculations as to the scale of the unfolding tragedy varied. Some experts gave warning that the oil would soon head east and then quite quickly loop around the bottom of Florida, carried by the Gulf stream and into the Atlantic.

No one could even say for sure how much oil was bleeding into the Gulf waters, although the US Coast Guard continued to estimate the flow at about 240,000 gallons a day. At that rate, more oil will be lost into the environment within weeks than was in the Exxon Valdez disaster of 1989.

The presidential visit was intended to repel criticism that Washington had been too sluggish in galvanising a federal response to the spill and, indeed, on applying proper pressure on BP to act to stop it. Senior government officials also fanned out yesterday to defend the White House's response.

"From day one we have prepared and planned for the worst even as we hope for the best," Mr Obama said outside the US Coast Guard station. "I am not going to rest ... until the leak at the site is stopped and the oil that has spilled is cleaned up."

Also on the defensive was Lamar McKay, the chairman of BP in the US, who said that engineers had almost completed plans to begin an attempt at placing a dome over the area of the leaks that might contain at least some of the leakage if it is successful. That could be done within six days, but he offered no guarantee it would work. The best solution – drilling an adjacent relief well – could take three months. "As you can imagine, this is like doing open-heart surgery at 5,000 feet, with, in the dark, robot-controlled submarines," he said.

A spokesman for BP in Louisiana said that the failed piece of equipment referred to by the chairman was the so-called Blowout Preventer which is meant to shut down the flow of oil at the sea bed in the event of a calamitous failure. The spokesman, Bill Salvin, would not speculate on the underlying cause of the accident. "We're not ruling anything out," he said.

Frustration continues to mount in local communities – particularly among fishermen who depend on the fragile ecosystems for their livelihood – that efforts to deploy booms to try to stop the oil hitting land have not moved more quickly. Last night the authorities shut down commercial and recreational fishing all the way from the Mississippi Delta to Florida.

The US Interior Secretary, Ken Salazar, agreed that it may be three months before the "ultimate solution" to the leak is in place – the drilling of the relief well. It's an admission that does nothing to ease the fears of some experts about what might come next. With the slick tripling in size during the weekend, some ventured that a broken pipe at the seabed may be leaking faster than anyone has so far realised.

"The spill and the spreading is getting so much faster and expanding much quicker than they estimated," said Hans Graber, Professor of Meteorology and Physical Oceanography at the University of Miami. That could mean the slick could travel over time far beyond the Gulf Coast. "It will be on the east coast of Florida in almost no time," Professor Graber said. "I don't think we can prevent that. It's more of a question of when rather than if."

Another expert, Ed Overton of Louisiana State University, gave warning of something even more dire: a comprehensive blow-out of the well sending far greater quantities of crude into the sea. "When these things go, they go 'Kaboom!'," he said. "If this thing does collapse, we've got a big, big blow."

The Homeland Security Secretary Janet Napolitano said the Obama administration had treated the explosion at the BP rig on 20 April as a potential disaster from the beginning. "The physical response on the ground has been from day one as if this could be a catastrophic failure," she said. Not so certain was Rene Cross, the owner of Cypress Cove Marina, which was the centre of the additional swirl caused by Mr Obama's visit here yesterday. "It's like they say about closing the barn door when the cows are already out," he lamented.

Recalling that residents in the area had barely recovered from the effects of Hurricane Katrina in 2005 before this happened, he noted the major difference between the two calamities: "Katrina was Mother Nature that you can't do anything to stop, but this thing has been man-made."

RSPCA ready to embark on rescue mission

A squad of clean-up experts is on stand-by to fly from Britain to the US to help decontaminate birds and other wildlife caught in the slick. More than 30 fully trained RSPCA inspectors have been told to be ready to travel "at a moment's notice" to help the clean-up operation along the coastline of the Gulf of Mexico.

Wildlife organisations in the US are preparing for the worst as the slickthreatens to overwhelm countless birds and other animals.

Until oil-covered animals, whether dead or alive, start being reported in any numbers, the scale of the rescue operation required remains uncertain. But US animal groups have already asked the RSPCA, which has specialist training and experience in this area, to remain ready to help.

Klare Kennett, an RSPCA spokeswoman, said: "We have spoken to the Americans about the problem. They have a specialist unit to deal with birds that get covered in oil and we have offered our services so if they need us at any time we will go over and assist.

"All of our inspectors are trained to deal with oiled animals and we have specialist teams who can go at a moment's notice. We probably have 30-plus inspectors who are ready to go to the States.

"They would take their equipment with them but mainly it's about expertise; how to handle the birds when they're being cleaned up.

"You can wash them and keep washing them but they can get very stressed so you have to do it as quickly as you can. It's also about safety – you wouldn't want to get pecked."