Arizona death row inmate Joseph Wood was injected 15 times with an experimental lethal drug cocktail during the nearly two hours that it took him to die.

Once was supposed to be enough.

Close video The ethics of the death penalty In the wake of a recent botched execution in Arizona, is there a new ethical debate to be had over the death penalty? Sarah Knight of Network Advancement at the American Constitution Society and Philip Hansten from the University of Washington discuss. In the wake of a recent botched execution in Arizona, is there a new ethical debate to be had over the death penalty? Sarah Knight of Network Advancement at the American Constitution Society and Philip Hansten from the University of Washington discuss. share tweet email Embed

The new revelations about the number of times the execution drug protocol was administered came through documents released by the Arizona Department of Corrections to the state’s office of Federal Public Defenders. Wood was sentenced to die for the 1989 murders of his ex-girlfriend and her father. Prior to his execution, Wood and several other inmates sued the state in order to ascertain information about the qualifications of the officials performing the execution, the source of the drugs, and how the lethal injection protocol was developed. That lawsuit is ongoing.

“We can’t tell at this point whether he suffered, but what we do know is that the experiment failed.” Dale Baich, attorney for executed prisoner Joseph Wood

“The people who were in charge of putting him to death really did not know what they were doing,” said Austin Sarat, a death penalty expert and professor at Amherst.

Wood’s attorneys have called for an independent investigation into his execution, while the Arizona Department of Corrections is conducting its own review.

“We can’t tell at this point whether he suffered, but what we do know is that the experiment failed. The department said one dose of this drug combination would be enough to kill a prisoner, and it was not enough,” said Dale Baich, Wood’s attorney. “Under the Arizona protocol, if the prisoner remains conscious, a backup set of drugs can be administered, but there’s nothing in the protocol that permits fourteen additional doses to be administered when the prisoner is unconscious.”

The U.S. Court of Appeals for the Ninth Circuit originally put a hold on Wood’s execution so that his lawsuit could proceed, but their decision was overturned by the U.S. Supreme Court and Wood was put to death on July 23. Witnesses at Wood’s execution said the condemned man spent an hour of his execution “gasping and snorting.” But witnesses couldn’t see how many times the drugs were administered, because the injections are made in a separate room, then pass through tubes attached to the inmate.

Wood was executed using a combination of hydromorphone and midazolam, the first time Arizona had used this particular drug combination. Midazolam has been associated with other botched lethal injections, according to the Death Penalty Information Center, which said in June that “nearly one-third of the executions using midazolam have had extremely troubling problems,” such as a prisoner who ”appeared to fall asleep but then started moving again.”

Anti-death penalty activists and companies averse to having their products associated with executions have contributed to a shortage of drugs used in lethal injections.

“It indicates yet again that’s what happening in various states that are trying to continue to use lethal injection is a period of experimentation on human beings,” said Sarat. ”Lack of availability of the drugs necessary to carry out that protocol has resulted in states trying out different things.”

Lethal injections, Sarat said, were more likely than other methods to result in botched executions. In a study of U.S. executions that took place between 1890 and 2010, Sarat said, 7% of executions by lethal injection were botched, compared to 3% for all executions.

Even before Wood’s execution, difficulties with lethal injection had provoked calls to adopt more effective – if gruesome – methods of killing. Dissenting from the Ninth Circuit decision that was ultimately reversed, Chief Judge Alex Kozinski wrote that lethal injection was a failed attempt to make the inherently brutal seem benign.

“If we, as a society, cannot stomach the splatter from an execution carried out by firing squad, then we shouldn’t be carrying out executions at all,” Kozinski wrote.