A postmortem analysis of samples of deactivated SAES St707 getter particles recovered from a glove box purification system was conducted to determine the cause for deactivation and eventual hydrogen capacity loss. Unused and used .getter samples were investigated by Auger Electron Spectroscopy (AES) and Mossbauer Transmission Spectroscopy (MTS) of 57Fe. Hydrogen absorption isotherms were measured to determine the extent of the hydrogen capacity loss, and the total impurity (0,N) loading levels were determined by vacuum fusion mass spectrometry. The effect of common gaseous impurities on the tritium-removal characteristics was investigated to determine the nature of impurity-getter interaction for different impurities. Hydrogen capacity loss observed in the purifier was found to be due to bulk nitriding, probably due to irreversible transformation of intermetallic Laves-phase Zr(Fe,V)2 to Zr4Fe2 (O,N)x. The temporary getter deactivation observed during operation of the purifier may have been caused by impurities such as CO, CO2 and volatile organics. Metallic Fe (considered to be responsible for dissociative chemisorption of H2) was found only on unused samples. A gradual loss of metallic Fe from the getter surface could also have contributed to getter deactivation.