Abstract: In a process for producing a hydrogen-containing gas, a hydrocarbon feed gas and steam are introduced into a reaction vessel containing a complex metal oxide and steam-hydrocarbon reforming catalyst thereby forming a combustible gas mixture comprising hydrogen. A regeneration gas comprising greater than 0.1 volume % oxygen up to and including 2 volume % oxygen is introduced into the reaction vessel to displace at least a portion of the combustible gas mixture from the reaction vessel. Subsequently, additional regeneration gases may be introduced into the reaction vessel. Numerous means for providing various regeneration gases are presented.