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Q & A: Depleted uranium ammunition health hazards

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Most recent answer: 10/22/2007
I heard in one of your previous answers that bullets are made out of uranium. If they’re uranium, how come the soldiers do not get cancer? Don’t they handle a lot of bullets?
- Socrates Fernandes (age 13)
SFS Seoul Foreign School, India
This is a very important question which has been hotly debated in recent years, due to the use of depleted uranium in ammunition fired in recent wars. (Ordinary bullets are made of lead, but the military has developed some special ammunition made of uranium. )

Depleted uranium is almost entirely made up of U238, which has a much longer half-life than U235, and therefore the nuclei decay much more slowly and emit much less radiation per pound of the stuff than U235. U235 spontaneously decays fast enough to be useful in making nuclear fuel for reactors or for weapons. Naturally-occurring uranium is mostly U238, with a small amount of U235 mixed in. The U235 may be separated out to make nuclear fuel, and the remaining U238 is a waste product, which is mostly useless. It is a bit less radioactive than natural uranium. It is dense, hard, and not too expensive, and so putting U238 in ammunition instead of making bullets entirely out of the much softer metal lead, sounds like a good idea if you want to make bullets that can punch through armor.

U238 decays by emitting alpha particles (two protons and two neutrons stuck together), and by spontaneous fission. Alpha particles have a very limited range through air (a few millimeters), and do not penetrate even very thin layers of most materials. Larger nuclear fragments travel with even more difficulty. Handling bullets probably isn't hazardous as long as direct contact is minimized, and as long as grinding, dust, and powder is not made which could be ingested. Current opinion from the European Union and the State Department is that the radioctivity in depleted-uranium ammunition poses a negligible health effect for soldiers using the ammunition as long as proper handling procedures are followed. (But it is an active area of debate and further reports can come out saying otherwise).

The people living around spent bullets may not be so fortunate. The uranium in a bullet may vaporize and burn when it strikes an armored vehicle, producing fine dusts of uranium and uranium compounds. These are toxic (most heavy metals are poisonous), and can be ingested. Alpha particles don't travel very far, but if the uranium is ingested into someone's body, they don't have to travel anywhere to cause their damage. It is a separate debate entirely if the residents of a country where a war is fought with depleted uranium ammunition are at an elevated health risk. Certainly the presence of depleted uranium will not make anyone any healthier.

Tom (w. Mike)

(published on 10/22/2007)

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