An inert gas stream containing parts per million levels of impurities such as O.sub.2, CO, CO.sub.2, H.sub.2, H.sub.2 O, is purified by passing the same sequentially through a first bed and second bed of material. In the first bed, carbon monoxide and hydrogen are both reacted with oxygen to form CO.sub.2 and H.sub.2 O. The latter is retained in this first bed while the reaction products and the inert gas stream are supplied to a second of material which is comprised of a getter. In this bed, oxygen reacts with the getter material and carbon dioxide is adsorbed therein so that the inert gas stream leaving the second bed is substantially free of such impurities. The first and second beds of material operate at temperatures up to about 38.degree. and these materials may be regenerated by heating the same to approximately 200.degree. C. and purging such beds with a purge gas flow.