The state of Alabama can't execute an incarcerated man using nitrogen hypoxia, a federal judge has ruled, finding the method violates the man's constitutional rights because a firing squad can be used instead.

The Alabama federal court ruled Tuesday that the asphyxiation protocol violated plaintiff Jeffrey Lee's rights under the Eighth Amendment as a cruel and unusual punishment, because Lee's proposed alternative method, the firing squad, is feasible. The case was on remand from the 11th Circuit.

"The State has failed to articulate a legitimate penological reason for refusing to adopt Lee's proposed alternative," U.S. District Judge Emily C. Marks said in the opinion. "Therefore, Lee has shown by a preponderance of the evidence that the protocol constitutes cruel and unusual punishment in violation of the Eighth Amendment."

Lee filed his lawsuit challenging the use of nitrogen hypoxia as a method of execution, claiming it had only been used five times in Alabama history. The state carried out an additional two hypoxia executions after Lee's lawsuit was filed in August of last year.

Alabama lawmakers allowed nitrogen hypoxia for the first time after amending laws in June 2018 in response to litigation over lethal injection drugs. States including Alabama began switching execution methods after drugmakers refused to manufacture drugs used to carry out lethal injections, the opinion said.

Under Alabama's nitrogen hypoxia protocol, the person facing execution is brought to the execution chamber, secured to a gurney and fitted with an industrial-use respirator. After officials read a death warrant and the condemned person is given a chance to say a few final words, pure nitrogen flows into the mask for 15 minutes or until five minutes after an electrocardiogram shows a flatline, whichever period is longer.

Lee's lawsuit says that during the execution, incarcerated people have suffered "exponentially longer" than officials with the Alabama Department of Corrections have claimed. Eyewitnesses to nitrogen hypoxia executions have claimed incarcerated people were "convulsing, shaking vigorously and gasping for breaths," the lawsuit said.

A federal district court found following a three-day trial in May that while the hypoxia method causes "one to three minutes of severe air hunger," it does not violate the Eighth Amendment. Lee appealed the finding, and the Eleventh Circuit on Monday reversed, finding the method carries a "substantial risk of serious harm," the district court said in its order.

Eleventh Circuit precedent requires that if an incarcerated person seeks to challenge an execution method, they must provide a feasible alternative method. Lee proposed a firing squad, the district court order said.

Alabama has vigorously challenged the use of a firing squad, citing difficulty finding five trained marksmen to carry out the execution. Judge Marks rejected the state's claims, however, instead finding that the state was unwilling to use an otherwise viable alternative to execute Lee, the opinion said.

The opinion said that because Lee had successfully proved that the hypoxia method was dangerous, and that the state refused to use his chosen alternative method, the state was permanently enjoined from using the nitrogen hypoxia method on Lee.

The court said the state could use other legal methods, such as electrocution, or the lethal injection protocol if the state were able to find the requisite drugs.

A spokesperson for the Alabama attorney general did not respond to a request for comment about Tuesday's federal court ruling. The Alabama Attorney General's Office released a statement on Monday vowing to continue pursuing the death penalty for Lee.

Attorney General Steve Marshall blamed what he called "a few far-left activists" at the ACLU and at a local online newspaper in Alabama who sought to have Lee's conviction overturned. The state's chief legal official also accused the organizations of wanting "dangerous criminals released back into our communities."

"For nearly 30 years, courts at every level have reviewed and upheld Lee's conviction and sentence," the release said. "As recently as one week ago, a federal court ruled that his method of execution is constitutional. Every legal avenue has been exhausted. The legal process has run its full and proper course."

Lee was convicted of a December 1998 double murder in which he used a sawed-off shotgun purchased from a pawn shop to kill two people and injure a third. Lee then fled to Georgia and was apprehended the following morning and returned to Alabama, the attorney general's press release said.

An attorney representing Lee did not respond to a request for comment.

Lee is represented by Paige Hester Sharpe, Angelique A. Ciliberti, Kevin Ashley Cline, Anna Ku Thompson, Caleb Thompson and Tommy Huynh of Arnold & Porter Kaye Scholer LLP.

The state is represented by Alexander Barrett Bowdre, Talmadge Butts, Polly Spencer Kenny, Robert M. Overing, Brenton Leigh Thompson and Lauren Ashley Simpson of the Alabama Attorney General's Office.

The case is Lee v. Lovelace et al., case number 2:25-cv-00680, in the U.S. District Court for the Middle District of Alabama.

--Editing by Linda Voorhis.