The Department of Corrections in New York State has tried to fire many prison guards for unjustified force against inmates. They are generally unsuccessful because of the union contract. It gives substantial job protection rights to the correction officers, including the right to arbitration. Arbitration rarely results in dismissal because unions have a hand in picking the arbitrators.
The inability to dismiss bad apples in turn creates a culture of impunity. The inattention of numerous guards permitted two notorious murders to tunnel out of an upstate New York State prison. Two prison employees actively aided their escape. The result was not only millions of dollars in costs to New York State, but nights of terror for nearby residents with natural born killers on the loose. And then the guards brutalized inmates with no connection to the escape in a search for scapegoats to cover up their own misfeasance.
Reducing the power of public unions in paramilitary forces, like correction officers and the police force, is one of the great civil rights issues of our time.