I don't think there is a concern about suffocation. but you should be aware that these tanks are pressurized to 2500 psi (in the states), and that can get pret

I don't think there is a concern about suffocation. but you should be aware that these tanks are pressurized to 2500 psi (in the states), and that can get pretty dangerous. use a new regulator with an overpressure release valve. myth busters did a segment where they chopped the top valve off a tank - it shot all 100lbs of steel through a cinderblock wall.