Two BP employees charged in the deaths of 11 rig workers claim the US Justice Department is trying to make them scapegoats for the Deepwater Horizon disaster.
The claims came after BP resolved a sweeping criminal probe of its role in the massive 2010 oil spill in the Gulf of Mexico.
Lawyers for the highest-ranking BP employees aboard the Deepwater Horizon during the deadly explosion in April 2010 vowed to fight manslaughter charges against their clients.
According to the indictment, Robert Kaluza and Donald Vidrine are accused of disregarding abnormal high-pressure readings that should have been glaring indications of trouble just before the blow-out.
Mr Vidrine's lawyer, Bob Habans, said in a statement that prosecutors showed "exceedingly poor judgment" in charging his 65-year-old client.
"It is almost inconceivable that any fair-minded person would blame this hard-working and diligent man for one of the most catastrophic events in the history of the oil business," Mr Habans said in a statement.
Mr Kaluza's lawyers, Shaun Clarke and David Gerger, said their 62-year-old client was a dedicated rig worker who "mourns his fallen co-workers every day."
"After nearly three years and tens of millions of dollars in investigation, the government needs a scapegoat," they said in a statement. "No one should take any satisfaction in this indictment of an innocent man. This is not justice."
Another indictment charges former BP executive David Rainey with obstruction of Congress and making false statements. Prosecutors said Mr Rainey, who was BP's vice president of exploration for the Gulf of Mexico at the time, withheld information that more oil was gushing from the well than BP had initially estimated. Mr Rainey's lawyers accused the Justice Department of trying to "turn a tragic accident and its tumultuous aftermath into criminal activity."
Meanwhile, London-based BP has agreed to pay a record 4.5 billion dollars (£2.8 billion) and plead guilty to felony charges involving the 11 deaths and lying to Congress about how much oil was spewing from the blown-out well. The settlement includes nearly 1.3 billion dollars (£820 million) in fines - the biggest criminal penalty in the nation's history.