Transocean owned the Deepwater Horizon rig, which exploded in April 2010, setting off a leak at the Macondo well in the Gulf of Mexico that took three months to cap. The company agreed to plead guilty to criminal charges, paying $400 million in fines, as well as another $1 billion in civil penalties for violations of the Clean Water Act, officials said.
The settlement and plea were filed with a federal court in Louisiana and still must be approved by a judge.
"This resolution of criminal allegations and civil claims against Transocean brings us one significant step closer to justice for the human, environmental and economic devastation wrought by the Deepwater Horizon disaster," Attorney General Eric Holder said. "This agreement holds Transocean criminally accountable for its conduct and provides nearly $1 billion in criminal and civil penalties for the benefit of the gulf states."
The explosion on the rig killed 11 workers and injured 17 more. By the time the leak was capped, nearly 5 million barrels of oil had spewed into the gulf, fouling beaches as far away as Florida and endangering marine life.
The disaster was the largest marine spill in the history of the oil industry.