Alabama, a US state with 165 people on death row, carried out the first-ever execution by an untested method known as nitrogen hypoxia.
The convicted manhad been on death row since 1996.
Nitrogen hypoxia is a method of execution where a respirator mask is placed over the inmate’s face, and their breathing air is replaced with pure nitrogen gas.
This deprives the individual of oxygen, leading to unconsciousness in a few seconds, and ultimately causing death in several minutes.
Lethal injection is the most common form of execution in the US and was also introduced as an experimental and “gentler” method in 1982.
The last execution in US using gas was in 1999, by using hydrogen cyanide gas.