A death row inmate has asked a federal court to halt his execution next month because Oklahoma has only one dose left of a lethal injection drug, and it might not work.
Pentobarbital has become hard to get after its manufacturer stopped selling it for executions last year.
An attorney for Michael Hooper said in a motion filed Tuesday that with one remaining dose, Oklahoma has no backup plan if the drug fails to render Hooper unconscious.
The motion mentions cases where anesthesia drugs "failed to take hold" but doesn't give specifics.
Concerns were raised in April after an Arizona inmate shook for several seconds upon receiving a lethal dose of pentobarbital. In that case, the drug was used by itself. In Oklahoma, it is used with two other drugs.