The need to accurately characterize inorganic oxidizers is evident because these materials are available to the general public and may be used to make improvised explosive devices. Following a review of the methods that have previously been employed for the analysis of inorganic oxidizers in explosive formulations and post-blast residue, the authors contend there remains a need for a methodology that can be used to rapidly provide initial assessment on the presence and identity of inorganic oxidizers. The addition of spectral libraries to the ESI-MS approach provides a feasible way to attain a real-time analysis; the approach has been successfully used in gas chromatography/mass spectrometry analysis of controlled substances. MS analyses were carried out with a Thermo-Finnigan LCQ ion trap mass spectrometer. A series of miniature pipe bombs filled with 1-3 g of oxidizer and sugar mixture were exploded to obtain post-blast residue samples. ESI-MS of oxidizers shows a series of characteristic cluster ions that can be thought of as a fingerprint of a particular oxidizer. The addition of a spectral library allows for the tentative identification of inorganic oxidizers through an automated and easy-to-use process. Moreover, the use of tandem mass spectrometry (MS/MS) further confirms the identity of the oxidizer in real-time. Among the advantages of this methodology are the ease of sample preparation, the small sample consumption, and that it can be readily implemented on various ESI-MS systems currently in use in analytical laboratories. Tables, figures, references