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Depleted Uranium Depleted uranium is being used by the US armed forces in the Iraq war as an effective penetration weapon against hardened targets. It is also injuring the health of GIs and others exposed to it. The term “depleted” refers to the fact that the uranium being used is the residue from the enrichment of uranium for use in nuclear power reactors or nuclear weapons. The principal isotope of uranium, U238, does not easily undergo fission, so it is not useful for nuclear power. The fissionable isotope, U235, occurs naturally in the ore at a level of only a few percent, too low to be useful. Various enrichment methods are used to concentrate the U235 about three-fold. The residue, depleted uranium, is one of the largest sources of nuclear waste. Modern nuclear weapons are not based on fission, as were the Hiroshima and Nagasaki bombs. About a thousand times more potent, thermonuclear weapons take advantage of fusion reactions in which isotopes of hydrogen are converted to helium, a reaction not involving uranium. The temperature required to induce fusion, however, is so high that it requires a uranium bomb as a trigger. The uranium trigger requires an even higher degree of concentration than for nuclear power, thus producing additional depleted uranium as a residue. The attraction of depleted uranium for warfare is that it is an extremely hard and dense material, one able to penetrate the armor plate of tanks and other military vehicles. A depleted uranium shell consists of a case filled with conventional explosive material in the center of which there is a protruding rod of depleted uranium. It is this uranium rod which is able to penetrate the armor of the target. There is no explosive blast as with conventional shells. What, however, is the point of punching a small hole in the side of a tank? Such a hole by itself neither disables the tank nor injures the personnel within. The key to its military effectiveness lies in the fact that finely divided uranium is pyrophoric; that is, it bursts spontaneously into flame. The enormous friction from the impact raises the temperature to a few thousand degrees, so high that it quickly oxidizes the metal to uranium oxide and pulverizes it into numerous minute ceramic particles. The particles are so small that they remain suspended in the air as an aerosol for hours. With the interior of the tank filled with this aerosol, normal breathing brings the uranium particles deep within the lungs of the crew. The particles are so small that they are able to cross over into the bloodstream. Their glassy nature, on the other hand, prevents them from dissolving, so they escape the ordinary detoxification and clearing mechanisms of the liver and kidneys. The high concentration of the aerosol within the tank proves lethal to the crew, partly from heavy metal toxicity. The aerosol produced by the weapon, although not a gas, since a gas consists of individual molecular units, is so finely divided that it has properties similar to a gas. Like a gas, it remains suspended in air for a long time and it spreads quickly through the air. For this reason, critics have argued that it is banned by the Geneva Protocol of 1925 forbidding the use of poison gas weapons. In other terms, depleted uranium can be considered a weapon of mass destruction. One reason that poison gas has been relatively little used is that the spreading of the gas is unpredictable and can affect one’s own troops as well as the enemy. Of course, it can kill civilians as well. It is now becoming clear that depleted uranium can act the same way, causing harm to our own troops who are exposed to it. Unlike poison gas, which causes immediate and unmistakable physiological distress, breathing low levels of uranium aerosol is done unawares and without warning. Although uranium 238 does not undergo fission, it is radioactive with a very long half life. Ordinarily, long-lived radioisotopes are not of great concern, since their emission is not very intense. Furthermore, the alpha particles produced in their decay penetrate much less than beta or gamma emission. In the case of the uranium aerosol, however, the situation is more critical. The fact that the uranium is not cleared through excretion means that the minute ceramic particles will be lodged in place for many years. This continuous exposure to even this low-intensity radiation can be harmful over the years. In addition, the extreme subdivision into minute particles means an extremely high aggregate surface area, thus raising the effective dose considerably. There is further hazard. When uranium does decay, it produces isotopes which may be much more dangerous than uranium itself, isotopes with shorter half lives producing beta or gamma emissions. Since the decay takes place within the ceramic pellet, these hot isotopes remain in place in the body. Although this casual exposure to radioactivity is insufficient to cause somatic damage, like the radiation sickness experienced by the Japanese atom bomb victims, it can cause genetic damage through injury to DNA in the body and in reproductive tissue. Birth defects can result from damaged sperm or ovaries (teratogenic effects). Cancer can result from damage to somatic tissue (carcinogenic effects). Another effect can be weakening of the immune system, allowing any number of other medical problems to emerge. Military personnel and innocent bystanders alike can be harmed by breathing the uranium aerosol. It is estimated that about one-third of American GIs participating in the Gulf wars since 1991 have developed Gulf War syndrome, probably caused by exposure to depleted uranium. These veterans have suffered from multiple serious physiological disorders and have received little or no official recognition, medical relief, or compensation. The
depleted uranium tale is another instance of the irony of successful warfare
turning on its perpetrators. Undertaking a preemptive strike against a
defenseless opponent falsely accused of having weapons of mass destruction,
using our own weapon of mass destruction, we have injured our own fighters
and their families, perhaps for generations into the future. Does this make
sense? Dom Roberti |