from the Independent UK:
....(snip)....
Word also came yesterday that the oil spill may be five times worse than previously thought. Ian MacDonald, a biological oceanographer at Florida State University, said he believed, after studying Nasa data, that about one million gallons a day were leeching into the sea, and that the volume discharged may have already exceeded the 11 million gallons of the 1989 Exxon Valdez disaster, widely regarded as the world's worst marine pollution incident. Mr MacDonald said there was, as of Friday, possibly as much as 6,178 square miles of oil-covered water in the Gulf.
Meanwhile, at the site of the ill-fated well, a mile beneath the surface, a massive metal chamber had been positioned over the rupture so it could contain and then capture the bulk of the leaking oil. The operation, which uses undersea robots, and has never before been attempted at this depth and pressure. But last night, the formation of ice crystals meant the dome had to be moved away from the leak.
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The interviews with rig workers, described to the Associated Press by Robert Bea, a University of California Berkeley engineering professor, recall the chain reaction of events that led to the disaster. They said that on 20 April a group of BP executives were on board the Deepwater Horizon rig celebrating the project's safety record. Far below, the rig was being converted from an exploration well to a production well.
The workers set and then tested a cement seal at the bottom of the well, reduced the pressure in the drill column and attempted to set a second seal below the sea floor. But a chemical reaction caused by the setting cement created heat and a gas bubble which destroyed the seal.
As the bubble rose up the drill column from the high-pressure environs of the deep to the less pressurised shallows, it intensified and grew, breaking through various safety barriers. "A small bubble becomes a really big bubble," Professor Bea said. "So the expanding bubble becomes like a cannon shooting the gas into your face." ..........(more)
The complete piece is at:
http://www.independent.co.uk/news/world/americas/million-gallons-of-oil-a-day-gush-into-gulf-of-mexico-1969472.html