This invention relates to a valve assembly for metal hydride hydrogen storage (MHHS) or chemical hydride hydrogen storage (CHHS) devices. The valve assembly comprises a body with an inlet connector for connecting to the MHHS or CHHS device, an outlet connector for connecting to an external device, a cavity in the body that is in gas communication with the inlet and outlet connectors, and a shut-off valve in the cavity that can be moved between an opened position that permits gas flow between the inlet and outlet connectors, and a closed position that denies said gas flow. The outlet connector has a first valve therein that is biased to remain closed when external pressure thereon is less than or equal to ambient pressure, thereby impeding at least atmospheric gas backflow into the cavity. The outlet connector can also have a second, one-way valve that permits gas flow out of the valve assembly only, as well as a bypass mechanism including a gas passage coupled to the cavity and upstream of the first and second valves, through which gas can be transmitted to the canister during charging.