Alabama has already tried once to execute Kenneth Smith. On the evening of Nov. 17, 2022, Smith lay on a gurney as workers tried for an hour to insert needles into the veins of his hand, arms and collarbone so they could put him to death by lethal injection. Just before midnight, the execution was called off.

Surviving an execution is uncommon. Only one other prisoner alive today has done it — a death row prisoner from Alabama whom the state also failed to execute by lethal injection. But Smith’s case is even more unusual. When the state again tries to execute him, on Jan. 25, Alabama plans to use nitrogen gas. It will be the first time the gas has been used as an execution method in the U.S.

The method has come under scrutiny for safety and human rights reasons. NPR exclusively published a document that showed the Alabama Department of Corrections had required Smith’s spiritual adviser, the Rev. Dr. Jeff Hood, to sign a waiver acknowledging that the state believes he could be at risk of exposure to the gas. In January, the United Nations published a statement that declared U.N. experts were concerned the method could lead to grave suffering.