Rapid structural oxidation resulting from accidental high temperature exposure of activated fusion material to reactive gases is potentially an important mechanism in the release of radioactivity or damage to the reactor. The reaction rates of 316 SS, HT-9, V-alloy, and TZM with air have been examined on the basis of theory and previous experiments. The low melting points of the primary oxides of the base metals cause oxidation of V-alloy and TZM to become very rapid above approximately 700°C, although vanadium species are far less volatile. The Mo content of 316 SS and HT-9 appears to make them susceptible to rapid oxidation above approximately 1000 and 1300°C, respectively. At such temperatures, the oxidation rates of steels are predicted to be over an order of magnitude less than Mo and V. The volatilization rates of TZM are expected to be several orders of magnitude higher than the other materials studied.