Nod for $400m fine in Gulf of Mexico spill A US judge has approved a $US400 million ($A388 million) settlement in criminal penalties against the rig operator involved in the 2010 Gulf of Mexico oil spill, the worst environmental disaster in American history. The punishment was part of a plea bargain agreement reached last month by rig owner Transocean and the US Justice Department. The penalty was approved on Thursday by Judge Jane Triche Milazzo of the US District Court for the Eastern District of Louisiana, in New Orleans. The blowout on the drilling rig Deepwater Horizon on April 20, 2010, killed 11 people and sent 4.9 million barrels of oil gushing from the sea floor into the Gulf, and was uncontrolled for almost three months in a tragedy that riveted the nation. Transocean pleaded guilty to one count of violating the Clean Water Act on account of negligence that led to the explosion of the Deepwater Horizon rig. Separately, Transocean has agreed to pay $US1 billion in civil penalties. It was operating the rig for BP, which for its part was fined $US4.5 billion over its role in the disaster.