Alabama executed a condemned man Thursday using nitrogen gas in only the second instance in the United States of the method's use, which drew criticism from human rights groups.
Alan Eugene Miller, a former delivery driver who was convicted in 2000 for a workplace shooting spree, was executed in the state prison in Atmore, the governor's office said.
Prison staff members put Miller, 59, to death via nitrogen hypoxia, in which a person breathes only nitrogen through a mask apparatus and is deprived of oxygen. It was also the second time Alabama moved to execute him after an execution squad struggled to do so two years ago by lethal injection.
Curtains to the death chamber were opened at 6:12 p.m. Miller said in a final statement that "I didn't do anything to be in here" and "I didn't do anything to be on death row," reported AL.com. Gas then appeared to flow into his mask at 6:16 p.m., media witnesses said.
AL.com reported that his fingers moved slightly when his spiritual adviser came to his side. Miller then pulled against his restraints, shaking and trembling for about two minutes, and periodically gasped for about six minutes, The Associated Press reported.
He was declared dead at 6:38 p.m., the state said.
His death caps a particularly busy period of executions nationwide with five occurring over the past seven days. They included Oklahoma carrying out an execution Thursday morning, South Carolina executing someone last week for the first time in 13 years and a Missouri man executed Tuesday who maintained his innocence in a case that drew national attention.
"Just as Alan Miller cowardly fled after he maliciously committed three calculated murders in 1999, he has attempted to escape justice for two decades," Alabama Gov. Kay Ivey said in a statement. "Tonight, justice was finally served for these three victims through the execution method elected by the inmate. His acts were not that of insanity, but pure evil."
Alabama in January became the first state to execute a prisoner using nitrogen; eyewitnesses reported the inmate, Kenneth Smith, 58, remained conscious for several minutes and violently thrashed and heaved while strapped to a gurney.
State Attorney General Steve Marshall has argued in court filings that the method is "swift, painless and humane."
In a statement following Miller's execution, Marshall accused political activists, out-of-state lawyers and the media of perpetrating a "misinformation campaign," and said the procedure went "as expected and without incident."
Miller initially sought to challenge the use of nitrogen. He filed a federal lawsuit in March seeking to halt his execution, citing the state's past execution failures and concerns that the method of nitrogen hypoxia would add pain and prolong death.
But Miller had opted for Alabama to use nitrogen, the state's alternative to lethal injection approved in 2018, after his execution in September 2022 was called off when staff members were unable to access a vein for more than an hour — a process Miller described as "excruciating" as two men punctured him several times in his arms and a foot. In his lawsuit, Miller said his weight, 350 pounds, has made securing an IV line "challenging."
The state agreed it would not try to execute Miller for a second time using lethal injection.
In July, Alabama officials posted unredacted documents related to Miller's suit in the federal courts' electronic filing system, shedding new light on the case before some of them were sealed.
The records, which were reviewed by NBC News, included a deposition in which Miller expressed concern that the execution team would have trouble securing a mask over his face to breathe in the nitrogen gas.
"Are these people that are going to fit [the mask], what's their training?" Miller said.
"I've got a big old head," he added. "Nothing else fits my head."
Miller had claimed the Alabama Department of Corrections refused to check whether the mask would fit him before the execution, but in his deposition, he declined an offer to have it fit-tested before the procedure.
"I think this is psychological terror right here," Miller said in his deposition.
However, the attorney general's office announced last month that Miller had agreed to settle his suit. The terms remain confidential.
"The resolution of this case confirms that Alabama's nitrogen hypoxia system is reliable and humane," Marshall said in a previous statement.
Miller's lawyers did not immediately return a request for comment.
With apparently no more legal barriers or plans by his legal team for a last-minute appeal, his execution went on as scheduled.
Miller does not contest that he was responsible for the 1999 shooting rampage south of Birmingham. Prosecutors said he fatally shot two co-workers, Lee Holdbrooks and Christopher Scott Yancy, and then went to a previous place of employment, where he confronted a former colleague, Terry Lee Jarvis, and killed him.
Testimony at his trial claimed that Miller was upset about "people starting rumors on me," according to court documents. In attempting to appeal his case following his conviction, Miller said he lacked the necessary intent to commit murder because he suffered from mental instability.
The use of nitrogen has raised concerns from human rights groups as states have looked for viable alternatives to lethal injection, a method that has become increasingly difficult to use because of a shortage of the necessary drugs.
If nitrogen, a naturally occurring, colorless and odorless gas, is not mixed with enough oxygen, it can cause physical side effects, such as impaired respiration, vomiting and death.
During an execution, medical experts say, a small amount of oxygen's getting into an inmate's mask as the inmate breathes nitrogen could lead to slow asphyxiation and prolong the time it would take to die.
The state has denied Smith's heaving was due to oxygen's leaking into the mask and argued that he held his breath, which hindered his becoming unconscious sooner.
Maya Foa, the U.S. director of Reprieve, a London-based human rights nonprofit group, said that the use of gas is akin to "human experimentation" and that studies indicate waning support for capital punishment among Americans.
"Whether by lethal injection or nitrogen suffocation, the myth of the 'humane execution' is a lie fewer and fewer people believe," Foa said in a statement.
