Carbon monoxide similarly replaces the oxygen in your red blood cells. There are even suicide tutorials online by using carbon monoxide as it’s a painless way to go.
Also, this is not advice and it’s also potenttially lethal to the people coming to save you. Don’t do it and if you do, for the very least, leave a sign warning others about it.
I don’t have anyone I’d want to remove and I’m also not so naive to think it wouldn’t come with major unpredictable consequences.