The invention relates to a head (2) for a tank (1) used to store pressurised gas, comprising, in an integrated manner: at least two components (131, 132) for treating, distributing and/or shutting off the gas; an upstream connector (20) suitable for being removably attached in a boss (4) of the tank (1); and downstream outlet pipes (211, 212) suitable for connecting the head (2) to any system using said gas by means of the aforementioned components (131, 132). According to the invention, each component (131, 132) comprises at least two sealing devices (141, 142) defining an intermediate space therebetween, and at least one pipe (12), called tapping pipe, connects each of the intermediate spaces and a common space (8) into which ail the tapping pipes (12) emerge, with an orifice (15) providing a connection between the common space (8) and a gas-detection device (16).