One day it will take a book or many books to categorize the gusher of BP's mistakes and miscalculations. But many damnable errors, spectacular misjudgments and horribly false assurances have already come to light since the start of this nation's Summer of Oil. Based on government hearings and investigative reports these past two months, here are the worst.
April 14-15: Six days before the explosion, BP won approval from the Interior Department's Minerals Management Service for a series of permit changes that would help it speedily conclude its over-budget drilling operation at Deepwater Horizon. BP had already won a "categorical exclusion" from the National Environmental Policy Act the previous year. The changes it got on April 14-15 allowed BP to install a cheaper, smaller, single pipe in the length of the well, rather than double-lined pipe. A double-lined pipe would offer protection from escaping gas, but BP argued that the single pipe made the best financial sense.
April 20: On the day of the explosion, BP executives came on board Deepwater Horizon to celebrate the rig's safety record. At the same time, Halliburton, a contractor for BP, was trying to temporarily plug and cap the well with cement so the drilling rig could be moved to another job. BP now says mud might have contaminated the cement Halliburton used.
Technicians noticed a rise in pressure from the well that suggested the cement wasn't holding. They did tests. One test showed a "very large abnormality.'' They took another test and misread it, declaring the well safe. BP called that a "fundamental mistake."
Although the pressure was rising, the workers began withdrawing drilling mud — which holds down oil and gas in the well. They replaced the drilling mud with seawater, which is standard procedure if all is well. Some workers say they objected but were overruled by a BP "company man." As they injected seawater, they observed a dangerous jump in pressure from oil and gas rising in the well.
The rig exploded.
Technicians then hesitated to switch on their last line of defense — a blowout preventer, which is supposed to seal the well in a disaster.
They waited for an official approval from BP. When they did switch it on, it had no hydraulic power. BP now says a seal may have leaked.
April 22: BP sent a robot camera down to look at the well. It said it found no leaking oil.
April 24: BP said it found some oil leaking from the well. It didn't know how much.
April 25: BP estimated a leak of 1,000 barrels a day. It sent four robots down to try to shut off the blowout preventer. The attempt failed.
April 28: BP estimated 5,000 barrels a day were leaking.
April 30: BP began spraying chemical dispersants directly on the gushing well, 5,000 feet below the surface, something no one has ever tried. The environmental impact is unknown, and last week the Environmental Protection Agency told BP to find a less toxic dispersant. So far, BP has not.
May 3: BP's CEO Tony Hayward said: "This is not our accident, but it's our responsibility. . . . We are going to defend the beaches. We will fix this." Oil began washing up on beaches the following weekend.
May 8: Operation Top Hat tried and failed. This was the attempt to cover the leak with a four-story containment dome. Icelike hydrates, a slushy mixture of gas and water, clogged the box. Hayward said he wasn't really counting on it to work.
May 14: Hayward said not to worry: "The Gulf of Mexico is a very big ocean. The amount of volume of oil and dispersant we are putting into it is tiny in relation to the total water volume."
May 16: BP inserted a mile-long tube into the broken riser pipe. It was able to siphon about 2,000 barrels a day into a tanker above. It was soon disconnected to set the stage for Operations Top Kill and Junk Shot.
May 26: Top Kill involved pumping millions of gallons of heavy mud into the well to try to force back the rising oil. Junk Shot came right after.
It involved shooting shredded tires and golf balls downward to clog the blowout preventer. The next day, Hayward said the work was going well. He gave it a 60 to 70 percent chance of success.
Americans could see for themselves how it went. A live video stream showed the mud pouring out of the blowout preventer. BP gave up on Top Kill.
Thursday: U.S. Geological Survey director Marcia McNutt said government scientists now estimate the oil is flowing in the range of 12,000 and 19,000 barrels per day, which means it is a bigger spill than the Exxon Valdez.
Sunday: Hayward dismissed reports of massive underwater plumes of oil, miles long, perhaps caused by BP's chemical dispersants. "The oil is on the surface," Hayward said. "Oil has a specific gravity that's about half that of water. It wants to get to the surface because of the difference in specific gravity."
This report is compiled from many published sources, including the St. Petersburg Times, Wall Street Journal, New York Times, Washington Post, Associated Press, Houston Chronicle and Baton Rouge Advocate. Times staff writer Craig Pittman and Times researcher Carolyn Edds contributed to this report. John Barry can be reached at (727) 892-2258 or firstname.lastname@example.org.