Just as efforts to kill the Deepwater Horizon gusher are nearing completion, a setback looms: a tropical storm that has halted all work and could send all the ships scurrying for cover.
A tropical wave now near Hispaniola, which is likely to dump rain on the Tampa Bay area this weekend, prompted Coast Guard and BP officials to bring the work on the relief well and the stacking cap to a near-standstill Wednesday.
"What we didn't want to do is be in the middle of an operation and potentially put the relief well at some risk," BP vice president Kent Wells said.
If the system strengthens into a tropical storm that threatens the oil spill site off the Louisiana coast, "any operations out there will have to be suspended," said Thad Allen, the retired Coast Guard admiral overseeing the cleanup.
Allen said he was waiting to see how the storm developed before deciding whether to order any of the ships and crews stationed some 50 miles out in the Gulf of Mexico to head for safety.
Operations off Louisiana aren't the only ones affected. Workers will soon begin pulling in boom that had been deployed along Pensacola's shoreline, the state Department of Environmental Protection announced.
"During a tropical storm, boom can cause additional damage to the natural resources that we are trying to protect from oil spill impacts," DEP Secretary Mike Sole said. "Given the current oil spill trajectories and the tropical activity in the Gulf of Mexico we think this is the best decision for Florida's communities."
The wave lost some steam Wednesday as it passed the mountains of Hispaniola, said National Hurricane Center spokesman Dennis Feltgen. It also showed no signs of low-level circulation.
But the wave could strengthen today as it moves away from Hispaniola, the island that includes the Dominican Republic and Haiti, and encounters favorable winds. Forecasters gave the tropical wave a 50 percent chance of developing into a tropical storm by Friday.
Feltgen said a hurricane hunter airplane would go into the storm today to take a closer look. It's too early to pinpoint where the system is headed, but Tampa Bay should expect higher rain chances this weekend.
Forecasters with Accuweather said the likely path would be across South Florida early this weekend, entering the eastern gulf as a weaker system and sending thunderstorms across the spill area. The choppy seas and gusty winds could send skimming vessels scurrying to port.
The storm is cropping up just as the relief well, expected to kill the Deepwater Horizon gusher for good, is nearly finished, Allen said.
Crews had planned to spend Wednesday and today reinforcing with cement the last few feet of the relief tunnel that will be used to pump mud into the gusher and kill it once and for all. But BP put the task on hold and instead placed a temporary plug called a storm packer deep inside the tunnel, in case it has to be abandoned until the storm passes.
Meanwhile the stacking cap is containing oil so well that the hundreds of skimmer boats cruising the spill site are "starting to have trouble finding oil" to pick up, Allen said.
But if a tropical storm is headed their way, the ships — some of which move very slowly — will need plenty of time to evacuate the area, Allen said. It would take them some time to move back into position once the storm passes.
"If we have to evacuate the area … we can be looking at 10- to 15-day gaps" before the ships can return to their current locations, Allen said.
The last ships to evacuate would be the ones controlling the robot vehicles monitoring the gusher, he said, and they would be the first ones back. That would still leave three to four days with no surveillance of the spill, he said.
Boat captains hired by BP for skimming duty were already being sent home and told they wouldn't be going back out for five or six days, said Tom Ard, president of the Orange Beach Fishing Association in Alabama.
If a tropical storm did hit the remaining slick from Deepwater Horizon, it would cause the oil that remains on the surface to become more weathered, turning it to tar balls that are easier to clean up. On the other hand, it could drive more oil onto the shoreline, and hurl tar balls and other oily debris further inland.
Information from the Associated Press was used in this report.