Alabama wants to carry out second nitrogen gas execution

The state of Alabama wants to carry out a second execution using the controversial method of nitrogen gas. 

It comes a month after the state carried out the first execution using the new method.

On Wednesday, Alabama Attorney General Steve Marshall's office asked the state Supreme Court to set an execution date for Alan Eugene Miller. 

Miller, 59, was convicted of killing three people during a pair of 1999 workplace shootings in suburban Birmingham.

"The State of Alabama is prepared to carry out the execution of Miller's sentence by means of nitrogen hypoxia," the attorney general's office wrote in a letter obtained by the Associated Press. 

What happened during the first execution?

The first inmate to be executed using the method was Kenneth Eugene Smith.

The execution took about 22 minutes, and Smith appeared to remain conscious for several minutes. For at least two minutes, he appeared to shake and writhe on the gurney, sometimes pulling against the restraints. That was followed by several minutes of heavy breathing, until breathing was no longer perceptible.

What is nitrogen hypoxia?

It's a method that involves forcing an inmate to breathe pure nitrogen, depriving them of oxygen which is needed to maintain bodily functions.

In regards to Smith the United Nations has previously said it is an "untested method of execution which may subject him to cruel, inhuman or degrading treatment or even torture" in a Jan. 3 statement.

U.N. experts said there's no scientific evidence to prove Smith won't experience "grave suffering," and implored U.S. officials at the state or federal level to halt the execution, pending review of the protocol.

"We are concerned that nitrogen hypoxia would result in a painful and humiliating death," the U.N. experts said.

In the U.S., veterinarians won't use nitrogen hypoxia in the euthanasia of most animals, except chickens, turkeys, and pigs, according to the 2020 American Veterinary Medical Association's euthanasia guidelines.

The Associated Press contributed to this story. It was reported from Los Angeles.