Abstract: The disclosure relates to a tank for storing volatile gas under pressure and a structure comprising the tank. The tank has a wall formed of a filament wound carbon fibre reinforced polymer (CFRP). The CFRP may have a graphene nanomaterial filler dispersed in the polymer adhesive matrix. The structure includes a frame for bearing static and dynamic forces from internal and external loads, the frame including the tank, the tank being an active load bearing structural element configured as a stressed member in the frame such that, in the structure in use, the tank bears static and dynamic forces from internal and external loads. One or more of: the filament winding pattern of the carbon fibre, the wall thickness, the wall shape, or the material properties of the polymer matrix including the dispersed graphene; is configured such that the tank has mechanical properties required by the design of the structure.