ABSTRACTPreliminary work suggests that Acoustic Resonance Spectroscopy (ARS) can non-invasively determine gas pressurization of waste drums. This is done by exciting the various mechanical vibrational modes of the test drum and analyzing the characteristics of the resulting resonance frequencies and their higher harmonics. If the contained waste is a liquid, the liquid level and also some properties of the liquid including density can be determined. Additional work is needed to exploit this novel acoustic technique for noninvasive characterization of waste storage drums.