After it took nearly two hours for an Arizona death row inmate to die by lethal injection, the death penalty is once again under fire, with leaders taking a closer look at how it's carried out.

Witnesses say convicted double murderer Joseph Wood gasped for air more than six hundred times in the fifty-seven minutes it took him to die on Wednesday. It's the third time this year there's been a controversial execution.

The American Civil Liberties Union now wants all executions halted.

"These are experimental cocktails and we don't have reason to know that these would work and we have reason to know that they don't work," said ACLU Activist Cassandra Stubbs

The family of Wood's victims doesn't have a lot of sympathy.

"Everybody's worried about - did he suffer? Who really suffered is my dad and my sister when they were killed," said Jeanne Brown.

Arizona's governor ordered a review of the state's execution procedures, but says Wood died in a lawful manner and didn't suffer.

The drug used in Wood's execution had never been used in Arizona before. It was the same two-drug combo used in botched executions in Ohio and Oklahoma earlier this year.

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In Tennessee, lethal injection protocol calls for a single drug.

Billy Ray Irick is scheduled to be the first death row inmate in Tennessee to die using the new single-drug method. He raped and murdered a 7-year-old Knoxville girl in 1985. His execution is set for October 7th.

Previous: Victim's brother: Wait for execution 'never-ending'

Until 2010, most states used a 3-drug combination for lethal injections. Tennessee was one of them.

But the drugs needed for that cocktail are now harder go get because drug makers that oppose capital punishment stopped selling to prisons and corrections departments.

To try to get companies to sell the drug, many states, including Tennessee, passed bills to withhold information about the drugs used for lethal injections and where they come from.

Tennessee lawmakers approved the bill last year.

And back in May, Tennessee brought back the electric chair.

Related: Electric chair brings life to old death penalty debates

Governor Bill Haslam signed a law that would allow electric chair executions if lethal injection drugs are unavailable.

The ACLU calls the electric chair a quote "extremely brutal and cruel means of execution."

Haslam said in May that the law will hold up in court.

"The Supreme Court has ruled that while the electric chair is not the means Tennessee uses, it is a means that is acceptable and does not constitute cruel and inhumane treatment," said Haslam.

10 death row inmates in Tennessee are scheduled to die through 2016. There are a total of 74 inmates on Tennessee's death row right now. Click here to see a list.