(NewsNation Now) — A death penalty expert said firing squads are “more humane” than lethal injection after two Oklahoma death row inmates chose the alternative execution style this week.

“They are more efficient,” Fordham University law professor and death penalty scholar Deborah Denno said on “Dan Abrams Live.” “They’re also more certain.”

The two inmates, Donald Grant and Gilbert Postelle, want a judge to grant them a temporary injunction that would halt their upcoming executions until a trial can be held over whether Oklahoma’s three-drug lethal injection method is constitutional. A trial on the issue is set to begin Feb. 28, but the judge has said in order to be added as plaintiffs, inmates must select an alternative method of execution. 

The push to reassess Oklahoma’s lethal injection methods comes after a high-profile execution went awry last year. In October, John Marion Grant convulsed and vomited as he was put to death for a 1998 slaying of a prison cafeteria worker. It was the state’s first execution in six years, following three consecutive botched executions or attempts in 2014 and 2015.

“From the very first lethal injection execution, every execution has been botched almost repeatedly after that point,” Denno said.

Last year, South Carolina became the fourth state to allow death row inmates to choose to die by firing squad. Utah is the only state to have used it in the last 50 years. They used it most recently in 2010.

“Of the three modern firing squad executions that have taken place and the last, as you said, was in 2010, they’ve gone off and seemingly flawlessly,” Denno said.

During a firing squad execution in Utah, a prisoner is strapped into a chair. A hood covers the face and a target is placed on the chest above the heart of the prisoner. A squad of sharpshooters, volunteers from a pool of corrections employees or law enforcement, then carry out the execution.

Denno believes the method is not used more because states think it might create “bad press” for them.

“It’s associated with a more primitive, more violent culture, even though the actual executions are far more humane, far quicker, and far more reliable than any lethal injection,” Denno said.