MONTGOMERY, Ala. (AP) — Lawyers for an Alabama inmate, scheduled to be executed with nitrogen gas this fall, argued in a Tuesday court filing that the state has ignored problems with the method as it seeks to carry out more nitrogen executions.

Attorneys for Carey Dale Grayson asked a federal judge to block the state from using the same nitrogen protocol that Alabama used in January to execute Kenneth Smith. The court filing cited witness descriptions of the execution and the findings of an autopsy conducted on Smith.

Alabama, after becoming the first state to carry out a nitrogen execution, has scheduled two additional executions with the new method. A second execution via nitrogen gas is set for Sept. 26 for Alan Eugene Miller. Grayson is scheduled to be executed Nov. 21.

“Rather than investigating what went wrong — as other states have done following issues with executions. Defendants have chosen to ignore clear and obvious signs the current protocol contains major problems that will result in more unconstitutionally torturous executions if it continues to be employed,” attorneys for Grayson wrote in the Tuesday night court filing.

The Alabama attorney general’s office declined to comment Wednesday on the court filing but has maintained that the method is constitutional. Alabama Attorney General Steve Marshall previously described the execution as “textbook.” The state will file a response later to the request for a preliminary injunction.

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Smith had blood and fluid in his lungs after his death, according to an autopsy conducted by the Alabama Department of Forensic Sciences. The state autopsy noted that his lungs when cut showed “marked congestion and edema with dark maroon blood.” It also noted that the tracheobronchial tree contained a “small amount of frothy fluid.”

An expert hired by Grayson’s legal team to review the autopsy wrote that the finding is “highly concerning.”

Dr. Brian McAlary, an anesthesiologist, wrote that it was the result of negative pressure pulmonary edema which occurs when drawing a breath is attempted against an upper airway obstruction, leading to fluid being drawn from blood vessels. He said it can also occur after strangulation or smothering with a plastic bag. He also wrote that the lack of a sedative given ahead of nitrogen gas increases the likelihood that the person will panic.

“Mr. Smith’s autopsy demonstrates what happens to the body when this panic response occurs. An individual experiencing panic and the sensation of the inability to breathe while also being denied oxygen will experience a constricted airway similar to an upper airway obstruction,” McAlary wrote.

Dr. Thomas Andrew, who retired after two decades as the chief medical examiner of New Hampshire, told The Associated Press that lung congestion is consistent with asphyxia as the mechanism of death. He said as the heart rapidly fails, “blood backs up and the lungs become quite congested.”

Andrew said he thought it was possibly a “bridge too far” to conclude there was an airway obstruction. However, he did agree that the lack of sedation could cause a person to panic.

“I think that’s a critical critique of the protocols used in this form of execution... You certainly will have a sense of the absence of oxygen, air hunger, and all of the panic and discomfort that is part and parcel of that way of dying,” Andrew said.

Alabama in 2018 authorized nitrogen gas as a new execution method. Grayson in 2018 selected it as his execution method but at the time the state had not developed a process for using it to carry out an execution.

Grayson was one of four teenagers convicted in the 1994 killing of 37-year-old Vickie Deblieux in Jefferson County. Prosecutors said Deblieux was hitchhiking from Tennessee to her mother’s home in Louisiana when four teenagers, including Grayson, offered her a ride. Prosecutors said they took her to a wooded area, attacked and beat her and threw her off a cliff. The teens later mutilated her body, prosecutors said.

Grayson is the only one of the four facing the death penalty because he was 19 at the time of the crime.