The approach of Tropical Storm Bonnie has forced BP Plc to halt efforts to permanently plug a gushing oil leak in the Gulf of Mexico, sending ships and workers retreating to safety.
Two rigs stopped drilling the relief wells intended to halt the leak for good and prepared to move out of the path of the storm, which was expected to hit the spill area tomorrow.
But the tropical storm has been downgraded to a tropical depression. There was a chance Bonnie could regain tropical storm strength as it moves out over the Gulf of Mexico this evening, but the Miami-based hurricane center said that it is unlikely.
Many non-essential workers have already abandoned the spill site.
Ships collecting seismic and acoustic data on the capped well and those operating underwater robots that provide a live feed of the wellhead would be the last to leave, and could stay if seas do not become too rough, officials said.
BP sealed the leak last week with a tight-fitting containment cap, choking off the flow of oil for the first time since a 20 April rig explosion killed 11 workers and sent crude spewing into the Gulf, soiling coastlines and devastating tourism and fishery industries.
The evacuation could push back BP's mid-August target date for a permanent solution to the leak to late August.
But the blown-out well will remain capped during the halt to operations, easing fears the gushing leak would resume.
The evacuation also delayed another potential solution, the launch of a ‘static kill’ operation to pump heavy drilling mud and possibly cement into the well.
BP said workers were securing eight company-operated platforms in the Gulf and preparing for a full evacuation of workers.
The US government said 28.3% of Gulf oil production and 10.4% of Gulf gas output by all companies had been shut ahead of the fast-moving storm.
Admiral Allen said the storm could have benefits and drawbacks for containment efforts.
Heavy waves and tidal churn could help break up the oil more quickly, but high winds and waves could drive it deeper into fragile wetlands and coastal areas.
‘In some scenarios it might actually be good for cleansing the system, but in other circumstances it might cause even more problems if it blows a lot of the oil directly onshore,’ said Chuck Kennicutt, a professor at Texas A&M University, who studied the 1989 Exxon Valdez spill in Alaska.
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Meanwhile, it has emerged in an investigation into events that led to the oil spill, that an emergency alarm that could have warned workers aboard the doomed Deepwater Horizon Gulf of Mexico drilling rig was intentionally disabled.
Mike Williams, chief engineer technician aboard Swiss-based Transocean Ltd's rig, said the general alarm that could have detected the cloud of flammable methane gas that enveloped the rig's deck on 20 April was 'inhibited.'
Mr Williams told a six-member federal board in Louisiana that
the rig managers 'did not want people woken up at 3am due to false alarms.'
The panel will convene for another week of hearings in Houston from 23-27 August , where high-level managers from BP and Transocean are scheduled to testify.
At this week's hearings, Transocean officials recited a litany of mechanical problems that plagued the rig.
The drilling in the Macondo well was said to be 43 days behind schedule and that rig workers referred to the rig as the 'well from hell.'
