Alabama has asked the state's Supreme Court to approve a date for death row inmate Alan Eugene Miller's execution,Christopher Caldwell which would be carried out using nitrogen hypoxia. 

The request, filed Wednesday, comes just under a month after Alabama executed Kenneth Eugene Smith using nitrogen hypoxia, the first time the controversial and widely-contested death penalty method was used in the United States. Both Smith and Miller had initially been scheduled to die by lethal injection, but Smith's first execution attempt was botched and Miller's was called off.

Miller's execution was originally scheduled to take place on Sept. 22, 2022, but it was called off when officials determined they couldn't complete the execution before the midnight deadline. Miller then filed a federal lawsuit arguing against death by lethal injection, which the Alabama Department of Corrections had tried to use in the first execution attempt, according to the suit. 

Miller said that when prison staff tried to find a vein, they poked him with needles for over an hour and at one point left him hanging vertically as he lay strapped to a gurney.

The state's highest court in Sept. 2022 ruled that Miller's execution could not take place by any means other than that of nitrogen hypoxia, and the Alabama Department of Corrections eventually agreed despite having earlier challenged the court's injunction.

Alabama Attorney General Steve Marshall said in Wednesday's filing the state is "prepared to carry out the execution of Miller's sentence by means of nitrogen hypoxia," adding, "it is once more the appropriate time for the execution of his sentence."  

Miller, now 59, was sentenced to death after being convicted of a 1999 workplace rampage in suburban Birmingham in which he killed Terry Jarvis, Lee Holdbrooks and Scott Yancy.

Alabama is one of three states that allows nitrogen hypoxia as an alternative to lethal injection and other, more traditional capital punishment methods. Oklahoma and Mississippi are the only other states that have authorized executions by nitrogen hypoxia.

Its application inside the execution chamber in Alabama has been criticized by some as experimental and, potentially, unnecessarily painful and dangerous for the condemned person and others in the room. United Nations experts cited concerns about the possibility of grave suffering that execution by pure nitrogen inhalation may cause. They said there was no scientific evidence to prove otherwise.

—Emily Mae Czachor contributed reporting.

In:
• Alabama
• Capital Punishment

S. Dev

S. Dev is a news editor for CBSNews.com.