A modified compressed gas cylinder for use in hydrogen powered vehicles which lessens the explosive danger from accidental collisions by using an electronic signal from the airbag system to open a normally closed pressure relief valve. The released hydrogen gas releases through a vent pipe which exits either through the fill pipe area or through a vent in the top of the automobile. A whistle on the vent pipe informs drivers, passengers and bystanders if the pressure relief valve is allowing the escape of hydrogen gas. A mechanical lever maintains the open position of the pressure relief valve once the airbag signal is received until the driver triggers a mechanical latch similar to a trunk release which returns the pressure relief valve to its normally closed position. The pressure relief valve can also open if for some reason the internal pressure of the hydrogen storage tank exceeds the appropriate safety level due to excess density and or temperature rise.