Published: Jul 23, 2010 10:53 AM EDT
Updated: Jul 22, 2010 11:17 PM EDT

ON THE GULF OF MEXICO (AP) - Work to permanently choke off the

oil well that had been spewing into the Gulf of Mexico was at a

standstill Friday after ships around the site were ordered to

evacuate ahead of the approaching Tropical Storm Bonnie.

There had been worries that the cap that has mostly contained

the oil would have to be reopened and left gushing if a major storm

came through. But engineers were confident enough in the strength

of the cap that they decided to leave it sealed while most of the

ships on the surface were told to leave the area.

Meanwhile, a tropical storm watch was issued early Friday for

the northern Gulf coast from Destin, Fla., to Morgan City, La.

The storm, which blossomed over the Bahamas and was to 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

Coast Guard Adm. Thad Allen and BP officials conceded. Even if it's

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," Allen said in Mobile, Ala.

Bonnie had maximum sustained winds near 40 mph (65 kph) early

Friday as it swirled about 155 miles (250 kilometers) southeast of

Miami.

The delay in work would be worse if BP had to fully open the cap

while the ships closely monitoring the well head left. More oil

would have been allowed to spew into the Gulf until they returned.

A week of steady measurements through cameras and other devices

convinced Allen they don't 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.

Allen said earlier in the day that evacuating the vessels could

leave the well head unmonitored for up to a few days. He said he

ordered BP to make sure the ships carrying the robotic submarines

watching the well are the last to leave and the first to return.

Allen issued the order 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 in a statement.

It was unclear Thursday night whether some of the vessels would

go back to port or head farther south in the Gulf out of the path

of the storm and await orders once the storm passes. The Coast

Guard cutter Decisive, the hurricane guard for the vessels at the

spill site, was awaiting instructions. In an evacuation, the

Decisive is the last vessel to leave the area.

Bonnie caused flooding in Puerto Rico, the Dominican Republic

and Haiti before reaching tropical storm strength later Thursday,

and Allen said crews expected sustained wind above 39 mph at the

spill site by early Saturday.

Seas already were 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 cleanup were called into port, Coast

Guard Rear Adm. Paul Zukunft said.

Louisiana Gov. Bobby Jindal said he expects local leaders in

coastal parishes to call for evacuation of low-lying areas as early

as Friday morning.

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 shouldn't 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, La.

Before the cap was attached and closed a week ago, the broken

well spewed 94 million to 184 million gallons into the Gulf after

the BP-leased Deepwater Horizon rig exploded April 20, killing 11

workers.

Work on plugging the well came to a standstill Wednesday, just

days before authorities had hoped to complete the relief shaft.

Allen said Thursday he has 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 Allen before starting the procedure.

Vice President Joe Biden visited cleanup workers in southern

Alabama, and said he was cheered the cap could remain on.

"After the storm's passage we will be right back out there,"

Biden said.