The federal commission investigating the BP blowout in the Gulf of Mexico has laid out for the first time its narrative of the disaster.

Eleven men were killed April 20 on the Deepwater Horizon rig. But while the investigators are putting together their version of events, the companies involved are still arguing over who is to blame.

So if you’re looking for one tidy explanation for the oil spill, you’re sure to be disappointed. Bob Graham, the former Florida governor and senator who is co-chairman of the commission, says it’s wise to consider the words of the federal panel that investigated the Columbia space shuttle disaster back in 2003.

“Complex systems fail in complex ways,” Graham said at a hearing Monday in Washington, D.C.

The commission laid out a long list of things that went wrong in the Gulf. It starts with bad cement, followed by a bad test to see if the cement was holding. Then, people on the rig missed warning signs that a blowout was imminent, and there are still major questions about how well the last line of defense, the blowout preventer, behaved during the disaster.

But with all this, the committee’s chief staffer, a theatrical trial lawyer named Fred Bartlit, started out calling into question a widely held belief about the disaster — namely, that BP cut corners to save time and money.

“We’ve studied the hell out of this,” he said. “We welcome anybody that gives us something we’ve missed, but we don’t see a person or three people sitting there at a table considering safety and cost, and giving up safety for cost. We have not seen that.”

As Bartlit set out to pull the pieces of information into a single narrative, he found he mostly agreed with BP’s own internal investigation.

For example, the commission agrees with BP that the oil and gas came up through the middle of the pipe in the oil well, not up and around its sides.

Representatives from the major companies involved in the disaster were called to testify at the hearing. And when they were asked whether anyone disagreed about where the oil came up, the man from Halliburton spoke up.

“I do disagree with the conclusion that’s drawn,” said Richard Vargo, who introduced himself as the cementing manager for the Gulf region.

Halliburton’s view is that the oil and gas squeezed up along the outside of the pipe. That was a result of a bad well design by BP, Halliburton contends, not because the cement job that Halliburton engineered was bad.

Vargo’s explanation about how the oil got outside of the pipe was highly technical and apparently even confusing to the BP man testifying at the hearing, Mark Bly.

Committee lawyer Bartlit asked Bly if he agreed with Vargo’s explanation.

“I could not follow the logic of his description,” Bly responded.

As the afternoon wore on, they debated evidence for and against this and many other elements of the disaster. And committee staff complained that they may never get to the bottom of some technical issues, because certain senators blocked the commission’s ability to issue subpoenas and gather testimony under oath.

But William Reilly, the other co-chairman of the commission, concluded that at heart it wasn’t a technical problem, it was a human failing — an assumption that the problems involved in sinking this well through a mile of water and two-and-a-half miles of rock were all routine and manageable.

“It’s very difficult for me to conclude that there was not a culture of complacency affecting everything involved with this exercise, with this experience,” Reilly said.

The commission continues hearing from experts Tuesday and has until mid-January to reach its final conclusions about the Deepwater Horizon disaster.

Copyright 2010 National Public Radio.