With billions of dollars at stake, the trial to figure out how much more BP and other companies should pay for the nation's worst offshore oil spill began Monday in New Orleans with the federal government saying the oil giant was mostly to blame for a disaster caused by putting profits ahead of safety.

Justice Department attorney Mike Underhill said BP, which leased the rig and owned the blown-out Macondo well, said the disaster resulted from the London-based company's "culture of corporate recklessness."

"The evidence will show that BP put profits before people, profits before safety and profits before the environment," Underhill said during opening statements.

Eleven workers died when the rig exploded April 20, 2010, and millions of gallons of oil spilled into the Gulf of Mexico. Unless a settlement is reached, the judge, not a jury, ultimately will decide months from now how much more money BP and other companies involved in the ill-fated drilling project owe for their roles in the environmental catastrophe.

"Despite BP's attempts to shift the blame to other parties," Underhill said, "by far the primary fault for this disaster belongs to BP."

Underhill heaped blame on BP executives and on-shore managers for cost-cutting decisions they made in the months and weeks leading up the disaster. He said the primary "rig-based" cause of the blowout was a botched safety test in which two BP rig supervisors, Robert Kaluza and Donald Vidrine, disregarded abnormally high pressure readings that should have been glaring indications of trouble.

Underhill said Vidrine and Mark Hafle, a BP engineer in Houston, discussed the test results over the phone less than an hour before the explosion but failed to take steps that could have prevented the blast.

"Instead, both men, armed with knowledge that could have saved 11 lives and prevented the Gulf oil spill, did absolutely nothing," Underhill said.

Kaluza and Vidrine have been indicted on federal manslaughter charges. Hafle hasn't been charged with wrongdoing.

BP has said it already has racked up more than $24 billion in spill-related expenses and has estimated it will pay a total of $42 billion to fully resolve its liability for the disaster.

But the trial attorneys for the federal government, Gulf states and attorneys for people and businesses hope to convince the judge that the company is liable for much more.

Hundreds of attorneys have worked on the case, generating roughly 90 million pages of documents, logging nearly 9,000 docket entries and taking more than 300 depositions of witnesses who could testify at trial.

Judge Carl Barbier has promised he won't let the case drag on for years as has the litigation over the 1989 Exxon Valdez spill, which still hasn't been completely resolved. He encouraged settlement talks that already have resolved billions of dollars in spill-related claims.

(Copyright 2013 by The Associated Press.  All Rights Reserved.)