1 Submitted to J. Nanomater. Mol. Nanotechnol. Nano-aluminum Thermite Formulations: Characterizing the Fate Properties of a Nano- technology During Use Aimee R. Poda 1,* , Robert D. Moser 2 , Michael F. Cuddy 1 , Zac Doorenbos 3 , Brandon J. Lafferty 1 , Charles A. Weiss Jr. 2 , Ashley Harmon 1 , Mark A. Chappell 1 , Jeffery A. Steevens 1 1 Environmental Laboratory, US Army Engineer Research and Development Center, 3909 Halls Ferry Rd., Vicksburg, MS, 39180 2 Geotechnical and Structures Laboratory, US Army Engineer Research and Development Cen- ter, 3909 Halls Ferry Rd., Vicksburg, MS, 39180 3 Innovative Materials &Processes LLC, 8420 Blackbird Ct., Rapid City, SD, 57703 Abstract Nanothermites represent an emerging class of highly efficient propellants/explosive materials whose environmental impacts are poorly understood. This work strives to examine the potential for exposure to the constituents evolved from nanothermites during their use. Several nanothermite formulations (e.g., Fe/Al and Bi/Al) were investigated following material trans- formation during end use. It is shown that these materials subsist with unique physical and chemical forms as compared to the original materials. End-use combustion processes result in the formation of inert spinel structures in the case of the iron-based formulations, whereas Bi 2 O 3 /Al composites react fully, transforming to metallic bismuth and aluminum oxide. In addi- tion, variations in size of combustion products suggest that some thermite formulations maintain their nanoscale whereas others are converted to size ranges consistent with the bulk material. The products of combustion are largely resistant to wetting and evidence suggests that transport in aqueous environments would be limited. Due to the particle size ranges found, it is speculated that the main transport route for these materials is aerosolization. These data will ultimately es- * Corresponding: Aimee.R.Poda@usace.army.mil / 1 601 634 4003