TULSA, Okla., April 18 (UPI) -- Oklahoma became the first state to approve nitrogen gas for executions, making it the state's backup method if lethal injection drugs can not be utilized.
Gov. Mary Fallin signed the law Friday, less than two weeks before the U.S. Supreme Court is set to determine if lethal injections are constitutional. The move also comes amid a nationwide shortage of lethal injection drugs.
Oklahoma is the third state to substantially change its methods of execution, but it is the first time a state added a method not already on the books. Utah made death by firing squad an alternative and Tennessee made the electric chair the alternative.
Before the new law Friday, the electric chair and firing squad were the other execution methods if lethal injection was unavailable in Oklahoma. The new law makes nitrogen gas the immediate backup and keeps the electric chair and firing squad as alternatives.
"Oklahoma executes murderers whose crimes are especially heinous," said Fallin, a Republican. "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 nationwide shortage of lethal injection drugs has forced changes, including fewer executions.
In December, Oklahoma changed the drugs used in Clayton Lockett's execution because of the shortage. It took 43 minutes for Lockett to die.
The U.S. Supreme Court is scheduled in late April to review the drug protocol used in Oklahoma and other states, partially in response to Lockett's death. Justices will determine if lethal injections violate the Constitutional ban on cruel and unusual punishment.