The first US execution using nitrogen gas is expected to be carried out today in Alabama after the Supreme Court rejected arguments that the procedure was at risk of being carried out incorrectly. The inmate, 58-year-old Kenneth Smith, was convicted in a 1988 murder-for-hire plot.
The vast majority of US executions over the past five decades utilize lethal injection. Alabama approved the use of nitrogen gas as an execution method in 2018 amid a shortage of the drugs required for lethal injection and mounting criticism over the method. The subject dies of nitrogen hypoxia—while the nontoxic gas makes up 78% of ambient air, the 100% nitrogen gas lacks any oxygen, effectively leading to suffocation.
The state attempted to execute Smith in 2022, but prison officials called off the procedure after repeatedly failing to connect the intravenous lines required for lethal injection.