the United States, including one in which 32 workers were exposed to a cloud of and its reaction products in 1986 at a Gore, Oklahoma, commercial uranium conversion facility. One person died; while a few workers with higher exposure experienced short-term kidney damage (e.g., protein in the urine), none of them showed lasting damage from the exposure to uranium. The U.S. government has been converting depleted to solid uranium oxides for use or disposal. Such disposal of the entire D inventory could cost anywhere from million to million. Military applications Depleted uranium is very dense; at 19,050 kg/m3, it is 1.67 times as dense as lead, only slightly less dense than tungsten and gold, and 84% as dense as osmium or iridium, which are the densest known substances under standard (i.e., Earth-surface) pressures. Consequently, a DU projectile of given mass has a smaller diameter than an equivalent lead projectile, with less aerodynamic drag and deeper penetration because of a higher pressure at point of impact. DU projectiles are inherently incendiary because they become pyrophoric upon impact with the target. Armor plate Because of its high density, depleted uranium can also be used in tank armor, sandwiched between sheets of steel armor plate. For instance, some late-production M1A1 and M1A2 Abrams tanks built after 1998 have DU modules integrated into their Chobham armor, as part of the armor plating in the front of the hull and the front of the turret, and there is a program to upgrade the rest. Nuclear weapons Depleted uranium can be used as a tamper, or neutron reflector, in fission bombs. A high density tamper like DU makes for a longer-lasting, more energetic, and more efficient explosion. Ammunition Most military use of depleted uranium has been as 30 mm ordnance, primarily the 30 mm PGU-14/B armour-piercing incendiary round from the GAU-8 Avenger cannon of the A-10 Thunderbolt II used by the United States Air Force. 25 mm DU rounds have been used in the M242 gun mounted on the U.S. Army's Bradley Fighting Vehicle and the Marine Corps's LAV-25. The U.S. Marine Corps uses DU in the 25 mm PGU-20 round fired by the GAU-12 Equalizer cannon of the AV-8B Harrier, and also in the 20 mm M197 gun mounted on AH-1 Cobra helicopter gunships. The United States Navy's Phalanx CIWS's M61 Vulcan Gatling gun used 20 mm armor-piercing penetrator rounds with discarding plastic sabots and