US Attorney General Eric Holder called the deal a "critical step forward" but was adamant that it did not end the criminal investigation of the 2010 spill.

The settlement announced on Thursday includes a $1.256 billion criminal fine, the largest such levy in US history. It was not, however, the "global" settlement some had hoped for, which would have also resolved the considerable federal civil claims against the company at the same time. "BP lied to me," said representative Ed Markey, the top Democrat on the House Natural Resources Committee who led investigations at the time of the spill. "They lied to the people of the Gulf. And they lied to their shareholders, and they lied to all Americans."

The government also indicted the two highest-ranking BP supervisors aboard the Deepwater Horizon during the disaster, charging them with 23 criminal counts including manslaughter. One man's lawyer said his client was being turned into a scapegoat for the disaster.

The April 2010 explosion on the rig in the Gulf of Mexico killed 11 workers. The mile-deep (1.6 km) Macondo oil well then spewed 4.9 million barrels of oil into the Gulf over 87 days, fouling shorelines from Texas to Florida and eclipsing in severity the 1989 Exxon Valdez spill in Alaska.

BP said it would plead guilty to 11 felony counts related to the workers' deaths, a felony related to obstruction of Congress and two misdemeanors. It also faces 5 years' probation and the imposition of two monitors who will oversee its safety and ethics for the next 4 years. The disaster has dragged BP from second to a distant fourth in the ranking of top Western oil firms by value.