First nitrogen gas execution in US has happened, but did it go as expected?

The Alabama attorney general said Friday that nitrogen gas is now a "proven" method of execution and that he believes more such executions will follow after the first one in the U.S. was carried out.

The inmate, Kenneth Smith, 58, was pronounced dead at 9:25 p.m. ET Thursday at the William C. Holman Correctional Facility in Atmore, Alabama – about 120 miles southwest of Montgomery – after the U.S. Supreme Court rejected a last-minute effort to halt the execution.

"What occurred last night was textbook," Attorney General Steve Marshall said during Friday's press conference. "And I now suspect that many states will follow. As of last night, nitrogen hypoxia as a means of execution is no longer an untested method. It is a proven one. It's the method that Kenny Smith ultimately chose."

However, there is criticism that the execution was not the humane, painless death state officials had said it would be in previous court appeals, with the person losing consciousness within seconds of inhaling the nitrogen and dying within minutes.

Instead, the execution took about 22 minutes from the time the curtains of the viewing room opened and closed, according to the Associated Press, during which time Smith reportedly shook and writhed on the gurney, pulling against the restraints "for at least two minutes" before he began breathing heavily and ultimately passed away.

Nitrogen hypoxia is the term for when enough nitrogen gas is inhaled that it deprives the body of oxygen -- in this instance, intentionally so, as a means of execution.

The protocol in Alabama calls for the condemned inmate to be strapped to a gurney and fitted with a mask connected to a breathing tube that administers 100% pure nitrogen to the inmate until they die.

Smith, who was sentenced to death for his role in the 1988 murder-for-hire of a preacher's wife, was originally set to be executed via lethal injection in November 2022. However, after several attempts, officials were unable to locate a vein to insert an intravenous line and were forced to delay the execution.

Smith and his attorneys had argued that death by nitrogen gas constituted "cruel and unusual" punishment under the U.S. Constitution. But Alabama officials said nitrogen hypoxia was a method Smith himself suggested when he was arguing that lethal injection was unconstitutional.

During the press conference, Marshall rejected criticism that the execution proceeded differently than what officials had described beforehand.

"The execution last night was not at all contrary to anything we filed, but in fact was entirely consistent, not only with what we filed, but also the experts that were retained on behalf of Mr. Smith," Marshall said. "There's no specific time that we can identify for which the nitrogen began to flow and so identifying that time no one can do. But we believe that not only was this constitutionally carried out, but entirely consistent with how it was planned from the beginning."

However, Associated Press reporter Kim Chandler, who says she has witnessed "most of the executions" in Alabama over the past decade and who witnessed Smith's execution, said "the movements exhibited by Smith were not typical for what you see in a normal execution."

"The state had maintained in court filings that consciousness could occur in seconds and death within minutes. It seemed to take longer than what was predicted in this court filings," Chandler said, adding, "I just think we're going to see extended litigation over what happened last night in Alabama. And we have continued, we will have continued disagreement over what Smith experienced and the meaning of those seizure-like movements and convulsions that he had for several minutes after the nitrogen gas began to flow."

Marshall said that 43 other inmates currently on death row in Alabama have chosen nitrogen hypoxia as their method of execution, and that the method will likely be used in more subsequent executions in the state.