NEW ORLEANS - The Department of Justice says the government dropped all manslaughter charges against two BP supervisors in the deadly 2010 Gulf oil spill because circumstances of the case had changed.

Department spokesman Peter Carr said Wednesday in a statement that the department determined it could "no longer meet the legal standard for instituting the involuntary manslaughter charges."

The manslaughter charges were dropped Wednesday against the two BP supervisors responsible for safety aboard the Deepwater Horizon oil rig where an explosion killed 11 workers in 2010.

One of the workers, Donald Vidrine, pleaded guilty Wednesday to a misdemeanor charge of violating the Clean Water Act.

Carr said a trial for the other defendant, Robert Kaluza, is scheduled for Feb. 16.