Abstract: A portable oxygen generating system using the principle of exothermic catalytic decomposition of an aqueous hydrogen peroxide comprising a feed tank having a mouth to receive liquid hydrogen peroxide, a cap to seal the mouth during operation and an outlet pipe, an on/off valve to control discharge from the feed tank, a regular valve to stop discharge from the feed tank when pressure in the system is equal to a predetermined pressure, a reactor containing a catalyst of lead strips in which hydrogen peroxide is decomposed, a cooling coil to cool and condense the reaction products, a separator tank to hold liquid water and gaseous oxygen, a return pipe to the feed tank to balance pressure in the system, a drain with a drain valve to discharge water, and a product line to supply oxygen for use by an operator of the system.