BP engineers in the Gulf of Mexico said they will leave the leaky cap fixed to its well head closed as key ships stationed over the site were ordered to evacuate today as Tropical Storm Bonnie loomed.
Bonnie, which blossomed over the Bahamas and will enter the Gulf of Mexico by the weekend, could delay by another 12 days the push to plug the broken well for good using mud and cement, retired US Coast Guard Admiral Thad Allen and BP officials admitted.
Even if it is not a direct hit, the rough weather will push back efforts to kill the well by at least a week.
"While this is not a hurricane, it's a storm that will have probably some significant impacts, we're taking appropriate cautions," Admiral Allen said in Mobile, Alabama.
He issued the order today to begin moving dozens of vessels from the spill site, including the rig that is 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.
A week of steady measurements through cameras and other devices convinced Admiral Allen they did not need to open vents to relieve pressure on the cap, which engineers had worried might contribute to leaks underground and an even bigger blowout.
The cap was attached a week ago, and only minor leaks have been detected.
The storm system caused flooding in Puerto Rico, the Dominican Republic and Haiti before reaching tropical storm strength last night and Admiral Allen said crews expected sustained wind above 39mph at the spill site today.
Seas were already choppy in the Gulf, with waves up to five feet, rocking boats as crews prepared to leave, and more of the smaller boats involved in the coastal clean-up were called into port.
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 cutters 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.
Scientists say even a severe storm should not affect the well cap, nearly a mile beneath the ocean surface 40 miles 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.
Charles Harwell, a BP contractor monitoring the cap, was also 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, Louisiana.
Before the cap was attached and closed a week ago, the broken well spewed 94 to 184 million gallons into the Gulf 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.
Admiral Allen said yesterday he had told BP to go ahead preparing for a second measure called a static kill that 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 Admiral Allen before starting the procedure.
US vice president Joe Biden visited clean-up workers in southern Alabama, and said he was pleased that the cap could remain.
"After the storm's passage we will be right back out there," he said.