Gulf storm threatens U.S. efforts to plug spill

HOUSTON (Reuters) - BP Plc oil spill workers in the Gulf of Mexico prepared for a possible evacuation on Thursday as a brewing tropical storm threatened more delays in attempts to end the environmental disaster.

U.S. officials said they would decide on Thursday night whether to unhook surface ships and evacuate the site, but said the blown-out well would remain capped even if an evacuation forces a temporary halt to undersea surveillance.

Some oil-skimming ships came ashore and the Gulf seas grew more choppy with high winds and rain moving northwest out of the Caribbean near the Bahamas. The system, which the National Hurricane Centre could become a tropical storm, is projected to swirl across the Gulf near the site where crews are working to plug the spill.

"We have determined that if we have to evacuate the site, we are prepared to leave the well capped," retired Coast Guard Admiral Thad Allen told reporters at a briefing.

BP evacuated nonessential workers from eight operated offshore Gulf facilities, but the evacuations did not affect operations at the spill.

"It's very possible that we could have wave heights that could exceed the operational envelope for all platforms," Allen said of the storm. "It will probably have some significant impacts."

The largest offshore oil spill in U.S. history, triggered by an April 20 explosion that killed 11 workers, has unleashed an environmental disaster in the Gulf and devastated the region's tourist and fishing industries.

BP capped the well last week, choking off the flow of oil for the first time since the explosion. The company is conducting pressure tests on the capped well, but those would be halted by an evacuation.

Workers also had been close to completing a relief well designed to permanently stop the spill and to launching a "static kill" operation to pump heavy drilling mud and possibly cement into the well.

Surplus boom and other equipment was being moved inland to prevent storm-related damage, an official said.

An evacuation could force a delay of 10 to 14 days in operations.

CRISIS FOR BP

The spill has sparked a crisis for British energy giant BP, which created a $20 billion (£13 billion) fund to compensate victims of the disaster.

BP shares remained relatively steady in New York trading, climbing 0.3 percent as the overall market rose. The oil giant is due to report quarterly results next week.

President Barack Obama, who has been under political pressure for his handling of the spill, will spend the August 14 weekend along the hard-hit Florida Gulf Coast, the White House announced.

Vice President Joe Biden visited Theodore, Alabama, on Thursday to assess BP's efforts, and met with fishermen and small business owners from the area.

"We are preparing for a short-term evacuation. Once the weather passes, we will be back out there," Biden told reporters. "We are ramping up and looking a lot better. We will resume as soon as possible."

The government announced it was reopening 26,388 square miles of Gulf waters to commercial and recreational fishing after tests and U.S. Coast Guard flights showed no oil in the area and fish showed no signs of contamination.

In a report to a federal judge in New Orleans, the Obama administration said it had complied with his order blocking the government's original six-month ban on deepwater drilling. But it also argued the case was moot because a revised suspension order has been issued.

The new moratorium, which lasts through November and bars new projects that use blowout preventers similar to the one used on the BP well, has already been challenged by one drilling company, Ensco Plc.

In a separate case, a federal judge ruled on Wednesday that all activity on oil and gas leases in the Chukchi Sea off Alaska must stop until regulators complete a more thorough review of how drilling there would impact the environment.

In a lawsuit filed by environmental and Alaska Native organizations, the judge said the U.S. government failed to abide by federal environmental law when it sold $2.66 billion worth of leases in the Chukchi in 2008, mostly to Royal Dutch Shell.

Workers on the doomed Deepwater Horizon drilling platform in the Gulf expressed concern about safety practices in a confidential survey conducted a month before the oil rig exploded, according to a survey commissioned by rig owner Transocean.

In the survey, workers said they "often saw unsafe behaviours on the rig" and indicated they feared reprisals if they reported mistakes or other problems.

(Additional reporting by David Alexander and Jeremy Pelofsky in Washington, Verna Gates in Alabama; Writing by John Whitesides; Editing by David Storey and Jackie Frank)