Extended storm warnings could force oil giant BP to re-open its capped well, allowing oil again to gush into the Gulf of Mexico until the bad weather passes, the US coast guard has said.
High winds and choppy seas could force the evacuation of dozens of ships working on the clean-up and halt operations to drill relief wells to permanently plug the disastorous leak.
The National Hurricane Center in Miami said a cluster of thunderstorms in the Bahamas formed into a tropical depression on Thursday and high winds and choppy waters are expected to hit Florida and the central Gulf region in the next several days.
Some fishermen hired by BP for oil skimming have already been sent home and told they wouldn't be going back out on the water for five or six days, Tom Ard, president of the Orange Beach Fishing Association in Alabama said.
Thad Allen, the retired coast guard admiral who is overseeing the US government's response to the oil spill, said that uncapping the well and calling ships back to shore is "necessarily going to be a judgement call".
Allen was watching the weather on Thursday to see how the storm developed before making a decision on the future of the clean-up effort.
Scott Dean, a spokesman for BP said on Thursday that no decisions on uncapping the well or removing clean-up ships have been made.
BP placed a temporary plug called a storm packer deep inside the well tunnel, in case it had to be abandoned until the storm passes.
"What we didn't want to do is be in the middle of an operation and potentially put the relief well at some risk," Kent Wells, BP's vice-president, said.
Transocean Ltd., the company which operates the rig drilling relief wells, has been watching the storm but had not planned evacuations on Thursday.
"Obviously as storm tracks toward the rig we'd have to take initial actions, pulling up subsea equipment, securing the location and preparing to move out of the way," Guy cantell, a company spokesman, said.
Scientists have been watching under-water video and well-pressure data for days, trying to determine if the capped well is holding tight or in danger of rupturing and causing an even bigger disaster.
BP's oil rig exploded on April 20 and experts believe that 35,000-60,000 barrels of oil poured into the Gulf of Mexico every day for about 13 weeks, threatening vulnerable wildlife and destroying local economies and communities.
The well cap, which was sealed in mid-July, is designed to stop the spill until BP August.