The hydrogen containing gases generated during operation and maintenance of a fusion machine need to be detritiated prior their discharge to the environment. The amounts, chemical and isotopic compositions of gas impurities which were decontaminated in JET Impurity Processing system during and after deuterium- tritium experiment, DTE1, are presented. Two different techniques for impurities detritiation were tested. The first technique is based on hydrogen containing species catalytic oxidation followed by water decomposition in reaction with uranium at elevated temperature. The second technique is direct decomposition of impurities with molecular hydrogen liberation in reactions with uranium at elevated temperatures. The results of the impurities detritiation using both techniques are given.