2 workers shoulder blame for 2010 BP oil disaster

"Though it is tempting to single out one crucial misstep or point the finger at one bad actor as the cause of the Deepwater Horizon explosion, any such explanation provides a dangerously incomplete picture of what happened — encouraging the very kind of complacency that led to the accident in the first place," the commission's January 2011 report says.

As well site leaders, Kaluza and Vidrine were the highest-ranking BP supervisors on the rig, each having four decades of experience in the oil patch.

Vidrine, 65, was on duty at the time of the April 20, 2010, explosion. Kaluza, 62, was filling in for another well site leader and had been on the rig only a few days before the blowout. He was in bed at the time of the blast.

The case against Kaluza and Vidrine centers on their roles in supervising "negative testing," which is designed to assess whether a cement barrier is effectively preventing oil or gas from flowing up the well.

The indictment says they had "multiple indications" from the negative testing that the well wasn't secure. Yet they allegedly failed to alert onshore engineers about the problems during the testing, accepted a "nonsensical explanation" for abnormal pressure readings and eventually decided to stop investigating.

When another rig worker attributed the pressure readings to a "bladder effect," Vidrine and Kaluza accepted that explanation.

"This explanation was scientifically illogical and was not recognized within the deep-water oil exploration industry," the indictment says.

Uhlmann said it's understandable that prosecutors would focus on the well site leaders' conduct because they were in charge of rig operations. However, he said the indictment could send a troubling message that the failures were limited to actions on the rig and not at higher levels of the company.

"Corporate culture and management policies are created far above the well site leaders," he said.