Second nitrogen execution in U.S. to take place Thursday

The Alabama Department of Corrections scheduled convicted murderer Alan Eugene Miller for execution by nitrogen gas hypoxia on Thursday. Authorities opted to use the emerging execution method after a previous lethal injection attempt on Miller failed when a vein could not be punctured within the timeframe allotted for the execution. Alabama conducted the first nitrogen gas execution in the United States in January, amid controversy. At that time, convicted murderer Kenneth Eugene Smith was executed after his lethal injection attempt also failed.

What’s controversial about a nitrogen gas execution? Nitrogen gas execution involves strapping a prisoner down with a gas mask on. The mask supplies the prisoner with nitrogen gas instead of oxygen, causing them to die of hypoxia. Some advocates maintain that the method is efficient and painless, while critics say it amounts to torture. They say smothering constitutes cruel and unusual punishment and should be considered illegal under the U.S. Constitution. However, the U.S. Supreme Court rejected an appeal from Smith’s attorney in January to halt the execution. January’s execution sparked both lawsuits and state legislation around the practice. Despite the controversy, Alabama Gov. Kay Ivey gave state corrections officers a 30-hour window to conduct the second nitrogen hypoxia execution in U.S. history.

What were Miller’s crimes? Miller killed three colleagues execution-style in August 1999, alleging the trio had started rumors behind his back, the Alabama attorney general’s office said in a press release. The court sentenced Miller to death in 2000, describing the murders as calculated, premeditated, and callous.

Dig deeper: Read Lauren Canterberry’s report on Swiss police arresting four people operating an assisted suicide pod with nitrogen gas.