Transocean Deepwater Inc. has pleaded guilty to a violation of the Clean Water Act for illegal conduct leading to the 2010 Deepwater Horizon disaster, Attorney General Eric Holder said.

The company was sentenced to pay $400 million in criminal fines and penalties.

Transocean owned the Deepwater Horizon rig that exploded on April 20, 2010, killing 11 people. The accident led to the worst oil spill in U.S. history.