A reservoir safely accommodates a fuel using a barrier layer, which at least partly separates the contact areas of the reservoir and/or contact elements to be protected. The barrier layer is formed of a fire-proof medium which displaces volatile and ignitable fuel having a density less than the density of the fire-proof medium, providing a chemical-physical separation of hydrogen from the air surrounding the reservoir. In vehicles, particularly aircraft, safe operation may be improved by application of the barrier in the reservoir. In one embodiment, there is an additional reservoir filled with an inert material that surrounds the hydrogen reservoir.