The governor of Tennessee has signed a bill allowing the southern U.S. state to use the electric chair to perform executions on death row inmates.
Republican Governor Bill Haslam signed the bill into law Thursday. Tennessee lawmakers passed the electric chair legislation in April.
The new law allows Tennessee to electrocute death row inmates in the event prisons are unable to obtain lethal injection drugs, which have become scarce since a European-led boycott of drug sales for executions.
Pharmaceutical companies in the United States have also begun refusing to supply the drugs needed for lethal injections, forcing state authorities to turn to more loosely regulated companies known as compounding pharmacies.
Lethal injection is the primary execution method in U.S. states that have capital punishment.
The Tennessee law comes as lethal injection is receiving more scrutiny as an execution method after last month's botched execution in Oklahoma. In that case, convicted killed Clayton Lockett received a new three-drug lethal injection combination that left him writhing on a gurney for several minutes before he eventually died from a heart attack.
Several death row inmates have launched court cases against their sentences, arguing that the use of less regulated pharmaceuticals could cause significant pain and is inhumane.
Amnesty International says there was a spike in the number of death sentences carried out worldwide in 2013, with China topping the list. The U.S. was fifth on the list with 39 executions, one place behind Saudi Arabia's 79.