BP engineers said they would leave the leaky cap fixed to its crippled Gulf of Mexico well head closed as key ships stationed over the site were ordered to evacuate 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 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.
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.
Scientists say even a severe storm shouldn't affect the well cap, nearly a mile beneath the ocean surface 40 miles from the Louisiana coast.