A method for inerting a protected space. Process water is delivered to an anode of an electrochemical cell where a portion of the process water is electrolyzed to form protons and oxygen. The protons are transferred across the separator to the cathode, and process water is directed through a process water fluid flow path including a first side of a membrane. Gas is transferred to a second side of the membrane to form a de-gassed process water on the first side of the membrane, and the de-gassed process water is recycled to the anode. Air is delivered to the cathode and oxygen is reduced at the cathode to generate oxygen-depleted air. The oxygen-depleted air is directed from the cathode of the electrochemical cell along an inerting gas flow path to the protected space.