There are 61 women on death row across the country, according to the Death Penalty Information Center, making up only 2% of the 3,125 inmates on death row across the country.  Take a look at all the women sentenced to death in the United States.  Source: Death Penalty Information Center
PAUL BUCK/AFP/Getty Images
There are 61 women on death row across the country, according to the Death Penalty Information Center, making up only 2% of the 3,125 inmates on death row across the country. Take a look at all the women sentenced to death in the United States. Source: Death Penalty Information Center
Now playing
01:27
Lethal injection explained (2014)
orig sanjay death penalty explainer npr mg_00002313.jpg
KJRH/Oklahoma Department of Corrections
orig sanjay death penalty explainer npr mg_00002313.jpg
Now playing
01:27
Lethal Injection: The process
death row stories botched executions_00004405.jpg
death row stories botched executions_00004405.jpg
Now playing
02:16
How executions go wrong
Alabama Police Department
Alabama Police Department
Alabama Police Department
Now playing
02:28
Witness: Inmate struggled during execution
Kenneth Williams Arkansas execution victim family orig vstan dlewis_00000000.jpg
Kenneth Williams Arkansas execution victim family orig vstan dlewis_00000000.jpg
Now playing
01:30
Victim's family fulfills killer's last wish
orig jag death penalty stats_00000214.jpg
orig jag death penalty stats_00000214.jpg
Now playing
01:22
The death penalty in America
orig who gets the death penalty cevallos _00010620.jpg
orig who gets the death penalty cevallos _00010620.jpg
Now playing
02:07
Who gets the death penalty?
Lethal Injection Drug Orig_00013204.jpg
Lethal Injection Drug Orig_00013204.jpg
Now playing
01:50
Court rules on the use of lethal injection drug
Now playing
01:24
Conservatives vs. the death penalty
Will Mullery/CNN
Now playing
02:04
Lethal injection at the Supreme Court in two minutes
Will Mullery/CNN
Now playing
01:23
Supreme Court Justice Breyer on the death penalty
pope francis death penalty abortion_00011325.jpg
pope francis death penalty abortion_00011325.jpg
Now playing
03:41
2015: Pope Francis calls for abolition of death penalty
kelly gissendaner georgia woman execution pkg_00010902.jpg
WGCL
kelly gissendaner georgia woman execution pkg_00010902.jpg
Now playing
03:20
Detective recalls how he put Georgia woman on death row
idesk intv dieter tennessee electric chair_00000210.jpg
WKRN
idesk intv dieter tennessee electric chair_00000210.jpg
Now playing
01:40
Tennessee to use the electric chair
exp Lead pkg brown botched lethal injection oklahoma _00013214.jpg
exp Lead pkg brown botched lethal injection oklahoma _00013214.jpg
Now playing
02:19
Execution drugs shrouded in secrecy
new dnt botched execution brown_00000904.jpg
new dnt botched execution brown_00000904.jpg
Now playing
04:33
Inmate dies after botched execution

Story highlights

Nitrogen gas causes a quick loss of consciousness and then death from lack of oxygen, Oklahoma says

The state's executions are on hold while the U.S. Supreme Court reviews the state's use of lethal injections

(CNN) —  

Oklahoma Gov. Mary Fallin signed a bill on Friday that would allow the state to perform executions with nitrogen gas if lethal injection is ruled unconstitutional or becomes unavailable.

Nitrogen causes a quick loss of consciousness and then death from lack of oxygen, Fallin’s office said in a press release. CNN affiliate KFOR says it’s never been used in an execution in the United States.

“The person will become unconscious within eight to 10 seconds and death a few minutes later. In other words, a humane, quick and painless death,” said Rep. Mike Christian, one of the bill’s authors, according to KFOR.

Robert Dunham, executive director of the Death Penalty Information Center, told the Washington Post that the same “painless” argument had been used to advance the use of lethal injections.

“The hasty manner in which this bill sped into law reflects the same lack of care with which Oklahoma has managed its execution process historically,” he said.

Oklahoma’s executions have been put on hold while the U.S. Supreme Court reviews its use of lethal injections. Last year, the state came under scrutiny when it took 43 minutes to kill convicted killer Clayton Lockett.

Fallin reaffirmed her support for the death penalty.

“Oklahoma executes murderers whose crimes are especially heinous,” Fallin said. “I support that policy, and I believe capital punishment must be performed effectively and without cruelty. The bill I signed today gives the state of Oklahoma another death penalty option that meets that standard.”

The governor’s office said the first alternative for execution is lethal injection, followed by nitrogen gas, the electric chair and the firing squad.