The Gulf of Mexico oil spill response faced a temporary setback heading into the weekend, as operations were halted due to the expected approach of tropical storm Bonnie.

In an update, the Gulf Unified Area Command Centre said it was tracking tropical weather near the Bahamas very closely and was constantly engaged in discussions with the National Hurricane Centre, the National Oceanic and the Atmospheric Administration and Federal Emergency Management Agency to ensure the safety of more than 40,000 people currently assisting in the oil spill response and recovery efforts.

Admiral Thad Allen, National Incident Commander overseeing the disaster response said, "Due to the risk that Tropical Storm Bonnie poses... many of the vessels and rigs will be preparing to move out of harm's way beginning tonight. Some of the vessels may be able to remain on site, but we will err on the side of safety." He added that the rig drilling the relief well — which it is hoped will ultimately kill the well — as well as other vessels needed for containment will also be moved from the areas at risk from the storm.

The Unified Command Centre further noted that boom was being removed from marsh areas where oil was not threatening the shore to prevent damage from the heavy equipment getting pushed into the delicate area by strong winds and high tides.

Underscoring his firm handling of BP’s role in the mop-up, Admiral Allen said that he had directed BP to "continue with the well shut-in procedure while the work to kill the well is temporarily suspended". He added he had insisted that BP take measures to ensure the vessels operating the remotely operated undersea vehicles were the last to leave the site and the first to return in order to maximise monitoring of the well. Monitoring of the site during the well integrity test remained one of the government's highest priorities, he said.

The administration said that while this latest response to avoid Bonnie would delay the effort to kill the well for several days, they were staging skimming vessels and other assets in a manner that would ensure that oil mitigation efforts were promptly re-started as soon as the storm passed and the safety of personnel was assured.

Biden visits again

Meanwhile Vice President Joe Biden made his second trip to the Gulf Coast since the oil spill began, on this occasion, meeting with Admiral Allen and other response personnel, inspecting boom and participating in a roundtable discussion with fishermen and small business owners.

In a statement after his visit, Mr. Biden said, "We’re not going to stop until this area, all the entire Gulf, has recovered; until the economy of the Gulf is revitalised and literally a way of life is restored. Because we’re not just talking about a natural ecosystem that’s in danger down here, we’re talking about an economic ecosystem. We’re also talking about a cultural ecosystem, a whole way of life," he said. "Whatever it takes to make this Gulf right, we’re going to make it right."

As per the administration’s data, to date 123,457 claims have been opened, from Americans who have suffered a financial loss as a result of the BP oil spill. Of this, the administration said, more than $234.9 million has been disbursed and no claims have been denied to date.

AP reports:

Tropical Storm Bonnie raked the low-lying Turks and Caicos Islands and the Bahamas with rain and lightning on Thursday, and forecasters at the U.S. National Hurricane Centre said the storm could reach the Gulf of Mexico by Saturday. The storm is expected to cross over the site of the spill.

Scientists say even a severe storm shouldn’t affect the well cap, nearly a mile (1.6 kilometers) beneath the ocean surface 40 miles (64 kilometers) from the Louisiana coast. “Assuming all lines are disconnected from the surface, there should be no effect on the well head by a passing surface storm,” said Paul Bommer, professor of petroleum engineering at University of Texas at Austin.

Still, it could delay by another 12 days the push to plug the broken well for good using mud and cement, retired Coast Guard Adm. Thad Allen and BP officials conceded.

“While this is not a hurricane, it’s a storm that will have probably some significant impacts, we’re taking appropriate cautions,” Adm. Allen said in Mobile, Ala.

Bonnie had maximum sustained winds near 40 mph (65 kph) early Friday as it swirled about 220 miles (350 kilometers) southeast of Miami.

A broken oil well has spewed somewhere between 94 million and 184 million gallons into the Gulf before the cap was attached a week ago. The crisis, the biggest offshore oil spill in U.S. history, unfolded after the BP—leased Deepwater Horizon rig exploded on April 20, killing 11 workers.

Some experts worry the hurricane season could worsen environmental damage from the spill, with powerful winds and large waves pushing oil deeper into estuaries and wetlands and also depositing more of the pungent, sticky mess on beaches.

Adm. Allen said forcing ships to move out could leave the well head unmonitored for up to a few days, and he ordered BP to make sure the ships carrying the robotic submarines watching the well were the last to leave and the first to return.

Adm. Allen issued the order on Thursday night to begin moving dozens of vessels from the spill site, including the rig that’s drilling the relief tunnel engineers will use to permanently throttle the free-flowing crude near the bottom of the well. Some vessels could stay on site, he said.

“While these actions may delay the effort to kill the well for several days, the safety of the individuals at the well site is our highest concern,” he said.

It was not yet clear whether the ships would go back to port or head farther south in the Gulf out of the path of the storm. The Coast Guard cutter Decisive, the hurricane guard for the vessels at the spill site, was awaiting instructions. It will be the last vessel to leave the area.

Bonnie caused flooding in Puerto Rico, the Dominican Republic and Haiti before reaching tropical storm strength.

Seas already were choppy in the Gulf, with waves up to five feet rocking boats as crews prepared to leave, and smaller boats involved in the coastal cleanup were called into port, Coast Guard Rear Adm. Paul Zukunft said.

Louisiana Governor Bobby Jindal said he expects local coastal leaders to call for evacuation of low—lying areas later on Friday.

At the spill site, the water no longer looks thick with gooey tar. But the oil is still there beneath the surface, staining the hull of ships motoring around in it.

One large vessel, the Helix Q4000, is burning off oil collected from the water, and bright orange flames flared at the side of the ship.

Charles Harwell, a BP contractor monitoring the cap, was confident.

“That cap was specially made, it’s on tight, we’ve been looking at the progress and it’s all good,” he said after his ship returned to Port Fourchon, La.

The spill began after the BP—leased Deepwater Horizon rig exploded on April 20, killing 11 workers.

Work on plugging the well came to a standstill on Wednesday, just days before authorities had hoped to complete the relief shaft. Adm. Allen said he has told BP to go ahead preparing for a second measure called a static kill, which would pump mud and cement into the well from the top, a move he said would increase the relief well’s chances for success. BP will have to get final approval from Allen before starting the procedure.