Oklahoma hasn't finished creating a new execution protocol involving nitrogen gas and it's unclear when executions will resume.
The Oklahoma Attorney General's Office and the state Department of Corrections say there is no estimated completion date for the new nitrogen-hypoxia protocol.
Officials announced in March their intention to switch to nitrogen hypoxia for executions after they had trouble obtaining lethal injection drugs. Officials had hoped to have the new plan drafted by July.
Executions have been on hold in Oklahoma since 2015, following several mishaps.
Robert Dunham is the executive director of the Death Penalty Information Center. He says the state is under court order not to perform any executions until a new protocol is in place.
State records show 16 inmates have exhausted all appeals and are awaiting execution dates.