A federal appeals court has issued a stay of execution for Missouri inmate Russell Bucklew, whose lawyers argued that he has a rare medical condition that would have made a lethal injection unnecessarily painful.

It would have been the first time an inmate was put to death since the botched lethal injection of Clayton D. Lockett last month in Oklahoma. That execution was stopped owing to complications and Lockett died of a heart attack about 40 minutes later.

The stay granted on Tuesday came hours before Bucklew was scheduled to die for a 1996 murder.

“Bucklew’s unrebutted medical evidence demonstrates the requisite sufficient likelihood of unnecessary pain and suffering beyond the constitutionally permissible amount inherent in all executions,” the U.S. Court of Appeals for the 8th Circuit wrote.

The Associated Press says it is not immediately clear whether the state will appeal to the U.S. Supreme Court.

The AP says Bucklew “suffers from a rare condition that causes weakened and malformed veins.” His condition is known as cavernous hemangioma.

“The state does not have the right to inflict extreme, torturous pain during an execution,” Bucklew’s attorney Cheryl Pilate said before the stay was granted.

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