BP well site leaders Robert Kaluza and Donald Vidrine, along with former BP vice-president of exploration for the Gulf David Rainey, remained free on bond following their arraignments in federal court.
Kaluza and Vidrine are charged with manslaughter in the deaths of 11 rig workers. They are accused of disregarding abnormally high pressure readings that should have been glaring indications of trouble just before the blowout of BP's Macondo well.
Rainey was charged separately with concealing information from Congress about the amount of oil that was leaking from the well. Millions of gallons of crude oil spewed from BP's well for months.
Kaluza professed his innocence on his way into court, making his first public comments since the April 2010 explosion that killed his co-workers.
"I think about the tragedy of the Deepwater Horizon every day," Kaluza told reporters. "But I did not cause this tragedy. I am innocent and I put my trust, reputation and future in the hands of the judge and the jury."
Kaluza and Vidrine's lawyers both accused the Justice Department of using their clients as scapegoats. They noted that other government investigations have spread out the blame for the disaster and concluded it was the product of a complex series of mistakes, made both onshore and on the rig.
"Bob and Don did their jobs," said Shaun Clarke, one of Kaluza's attorneys. "They did them correctly and they did them in accordance with their training."
Robert Habans, one of Vidrine's lawyers, said his client diligently followed instructions he received from engineers and others onshore.
"He's not the architect or the engineer. He didn't design the well, and he didn't make the critical decisions in this case," Habans said.
The case against Kaluza and Vidrine centres 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.
Habans, however, said court records related to civil litigation over the spill indicate Vidrine did discuss the test results with an onshore engineer less than an hour before the blast. A Justice Department attorney questioned a BP expert about the phone conversation between Vidrine and the engineer, Mark Hafle.
"It's almost inconceivable to me that the government in the indictment makes a contrary allegation," Habans said.
But the indictment appears to fault Kaluza and Vidrine for failing to phone engineers on shore earlier that day while the tests were being performed.
Lawyers for Rainey declined to comment. A Justice Department spokeswoman also declined to comment.
A trial for Kaluza and Vidrine is scheduled to start on Feb. 4, while Rainey has a Jan. 28 trial date. Both dates could be postponed given the complexity of the cases.
BP announced earlier this month that it will plead guilty to manslaughter, obstruction of Congress and other charges and pay a record $4.5 billion in penalties to resolve a Justice Department probe of the disaster.
Attorneys for BP and the Justice Department are scheduled to meet Dec. 11 with a federal judge to discuss a date for the company to plead guilty.
The Deepwater Horizon oil rig, owned by Transocean Ltd. but operated on behalf of BP, was drilling in the Gulf of Mexico off the Louisiana coast on April 20, 2010, when it was rocked by an explosion. The bodies of 11 workers were never recovered.