Why do people keep speculating on the reason it took a reported 22 minutes? It’s more likely that asphyxiation regardless of the method implemented is a poor way to execute people. I’m aware of the science behind using this gas but it’s never been used in this specific way. Now we are trying to say the mask wasn’t sealed around his face? What about the small traces of oxygen already in his lungs? What happens when his body switches over to anaerobic metabolic functions to try to keep the body alive. Probably the seizure like convulsions they saw. Acting as if this is a sound way to kill people but it “just needs to be done properly” is laughable at best. First, states that love executions don’t really care about getting it right. All the other forms of execution were said to be painless and quick when done “right”. Second, the humane execution came about for the executioner not for the condemned. The person turning on the gas wants to go home and think they just made the person slip into death peacefully. But the reality is killing is killing. Humanity only knows of one fullprof way for a painless death. Severing the brain instantly.