From Reddit:
It depends. You can die in multiple ways from solvent abuse.
There's lack of oxygen, frostbite, and cardiac arrest or failure. Most commonly is aspiration of vomit while they are unconscious and lack of oxygen.
It really depends on what one is inhaling, what methods they are using (using a bag is much more dangerous than just sniffing because you are limiting the flow of oxygen) and the condition they are in.
There are safer ways to get high than sniffing gasoline.
Shitty way to go I think. I get nauseous whenever some douche that drowned himself in Axe body spray walks by me.