When Pd gains or loses hydrogen or deuterium, the lattice expands or contracts causing a change in physical dimension. Under certain conditions, there is an additional expansion that is largely irreversible. Repeated gain and loss of hydrogen caused this excess volume to steadily increase. After all dissolved hydrogen has been removed, the diameter of a rod is found to have increased and the length to have decreased. These changes suggest the creation of micropores and/or dislocations within the metal. Such changes in the ennvironment with Pd metal can alter the local D/Pd ratio, affect the diffusion of impurities and, perhaps, affect the Fleischmann‐Pons Effect.Palladium cathodes that have been purposely contaminated with tritium show a rapid removal of the tritium with over 95% going into the evolved gas. This loss of tritium is first‐order with a half‐life that depends at least on cell current, amount of excess volume and electrode shape. The pattern of tritium release is consistent with the presence of micropores and is significantly different from that observed in active cold fusion cells. When used as an anode, over 99% of this dissolved tritium appears in the electrolyte thereby providing a method for its quantitative determination.