a canister assembly 200 according to an exemplary embodiment in which solenoid valve 6 has been placed on plug enclosure 2 instead of on manifold port 19 in this embodiment plunger 15 of male fitting 14 of solenoid valve 6 may interface with manifold port 21 shown in fig7 b o ring seal 5 on male fitting 14 would provide a tight seal with manifold port 21 manifold port 21 may include for example a recessed manifold inlet 22 having an electrical connection 23 that connects to solenoid valve 6 and activates plunger 15 as shown in fig7 a a check valve 20 may also be present to prevent the back flow of gas the valve arrangements of fig1 and 2 would provide a redundant fuel shut off system hydrogen gas would be prevented from entering manifold port 19 21 or leaving canister 1 unless an electronic control device not shown has activated delivery valve mechanism 4 gas could not flow backwards out of manifold port 19 21 due to the action of a check valve 20 shown in fig7 a likewise gas could not enter manifold port 19 21 unless a canister 1 is properly placed in connection to manifold port 19 21 solenoid valve 6 should be properly aligned and activated by control.