Depleted uranium (DU) weapons refer to munitions and armor that are made of DU, a toxic metal that is the by-product of a nuclear reaction. For munitions, this means that the bullet is made of DU while the shell casing is made of steel. In terms of armor, such as tanks, the DU is sandwiched between two pieces of rolled steel. In addition to its military applications, DU has civilian uses: It is used in aircrafts, shipping, and radioactive shielding. Although DU is not as radioactive as enriched or unadulterated uranium, it is still a hazardous substance, and, [Page 484]thus, its use raises health concerns. DU weapons are significant in the history of warfare because they are an important development in anti-armor munitions.