(Reuters) – BP Plc will pay $4.5 billion in penalties and plead guilty to felony misconduct in the Deepwater Horizon disaster, which killed 11 workers and caused the worst U.S. offshore oil spill ever.

The settlement includes a $1.256 billion criminal fine, the largest such levy in U.S. history, the oil company said on Thursday. Wall Street analysts said the deal will allow BP to focus again on oil production.

One U.S. senator from Louisiana said he hoped the settlement would not prevent his state and others for collecting civil penalties. An environmental group said BP should ultimately pay billions more.

The April 2010 explosion on the Deepwater Horizon rig in the Gulf of Mexico killed 11 workers. The mile-deep 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.

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