Oxygen is required for treatment of patients in hospitals and at home, in industrial processes and for fuel combustion. Most commonly oxygen is produced by cryogenic or pressure swing adsorption routes. Other techniques include oxygen-ion conducting ceramic membranes, polymer membranes and chemical processes used mainly in civil aviation to reduce the condition of hypoxia at high altitudes. Water electrolysis is used mainly for the production of hydrogen with oxygen as a by-product. In order to use this system only for oxygen production, hydrogen must be utilised and disposed off safely. This, however, is not practical in many instances where there is no use for hydrogen and it poses an explosion hazard. In this paper, an electrolyser system based on polymer electrolyte membrane is described in which hydrogen produced on one side of the electrochemical cell is consumed by combining it with atmospheric oxygen, through operating the cell in a carefully configured fuel cell mode. This reduces the power consumed in the electrolysis operation by more than 35% and eliminates hydrogen in exit gases. Oxygen generated is of high quality and can be used for human consumption (portable and plug-in home care oxygen therapy devices, in hospitals, defence or aerospace requirements) and for many other industrial applications. (C) 2009 Published by Elsevier B.V.