One week before a man's scheduled execution for killing a baby, the head of Oklahoma's prison system says he's confident in his staff's ability to carry out the first lethal injection in the state since one went awry in April.

Department of Corrections Director Robert Patton told the Board of Corrections on Thursday that the staff at the Oklahoma State Penitentiary in McAlester has worked "very hard" to prepare for the execution and three others planned soon.

Charles Warner is scheduled to die next Thursday for the 1997 killing of his roommate's 11-month-old daughter. Warner was scheduled to be executed the same night as Clayton Lockett, whose lethal injection went awry when an intravenous line failed.

Warner and other death row inmates are suing to stop their executions.