A death row inmate at Oklahoma’s state penitentiary reportedly began to convulse and vomit after he was executed last Thursday. His body’s reaction to the state’s lethal injection method has sparked renewed criticism surrounding the three-dose lethal cocktail used in states throughout the nation.

Oklahoma inmate John Marion Grant, 60, was Oklahoma’s first inmate to be executed after executions were paused six years ago. Grant was serving what amounted to a life sentence for several armed robbery convictions. During his time behind bars, he attacked and killed prison cafeteria worker Gay Carter.

The state’s pause on executions came after two inmates’ executions went awry in 2014 and 2016. In 2014, Clayton Lockett’s death took 43 minutes, while the 2015 death of Charles Warner left him crying out that he felt like his body was on “fire.” An autopsy of Warner’s body revealed that he was killed with an incorrect mixture of drugs. The autopsy led then-governor Mary Fallin to call off the upcoming execution of Richard Gossip that was set to take place the same year. The lethal cocktail used in Lockett’s and Warner’s execution was the same three-dose injection used in Grant’s execution.

Local KOKH reporter Dan Snyder witnessed Grant’s execution and afterward explained that Grant’s entire upper back repeatedly lifted off the gurney," Snyder said. "As the convulsions continued, Grant then began to vomit."

Grant was executed and declared dead at 4:21 by Oklahoma Corrections Department spokesperson Justin Wolf. Reports from witnesses detail that Grant began to convulse and vomit after he received midazolam, the first of Oklahoma’s three-drug lethal injection cocktail. Snyder shared with CNN that after receiving the first drug, Grant began to show adverse reactions. Sydney described medical staff members entering the room on multiple occasions to remove the vomit from Grant who was still breathing at the time. At 4:15, Grant was declared unconscious and the second and third drugs were administered.

Following the execution, the Director of the state’s corrections, Scott Crow, shared in a statement that “This execution was carried out in accordance with Oklahoma statutes. The Oklahoma Department of Corrections followed policies and procedures without complication.” Despite this announcement, Snyder later tweeted, “As a witness to the execution who was in the room, I’ll say this: repeated convulsions and extensive vomiting for nearly 15 minutes would not seem to be “without complication.”

Another AP reporter who witnessed Grant’s execution recalls Grant convulsing at least two dozen times after he was injected with midazolam.

Robert Dunham, the executive director of the non-partisan Death Penalty Information Center, echoed his concern. “I’m not aware of a case like this, where there were such strong and prolonged full-body convulsions and vomiting,” Dunham told Vice News.

A retired AP reporter also shared with Vice that after witnessing 450 executions, the reporter had only seen an inmate vomit one other time.

The botched execution has raised concerns yet again over the state’s lethal injection cocktail, particularly the first injection, midazolam. An NPR report that looked into midazolam details mounting evidence that the drug is an inhumane method for ending life.

Anesthesiologist and expert physician on lethal injections, Dr. Joel Zivot, analyzed more than three dozen autopsy reports of inmates who received midazolam. Their analysis shows that in about three-quarters of the cases, inmates experienced pulmonary edema or fluid in their lungs. The condition is associated with subjects feeling a sensation similar to drowning. "I began to see a picture that was more consistent with a slower death," Dr. Zivot explains. He adds the autopsies detail “a death of organ failure, of a dramatic nature that I recognized would be associated with suffering."

Midazolam has been used as the first drug in Oklahoma’s three-drug lethal injection execution since 2014, with Lockett being the first to receive it. Midazolam was introduced after the standard lethal injection cocktail that included anesthetic sodium thiopental was longer available because the only US manufacturer stopped making it. Manufacturers in Europe had the drug needed for the cocktail but refused to sell to those who planned to use it in executions.

Midazolam is currently used in three-dose lethal injection cocktails in Alabama, Arkansas, Florida, Ohio, Tennessee, and Virginia. Ohio and Arizona also use the drug in their two-drug lethal injections. Louisiana, Kentucky, and Oklahoma have also considered using midazolam in a two-drug cocktail as well but have not moved forward in doing so.