Depleted uranium is a heavy metal that is also slightly radioactive. Heavy metals (uranium, lead, tungsten, etc.) have chemical toxicity properties that, in high doses, can cause adverse health effects. Depleted uranium that remains outside the body can not harm you.
A common misconception is that radiation is depleted uranium's primary hazard. This is not the case under most battlefield exposure scenarios. Depleted uranium is approximately 40 percent less radioactive than natural uranium. Depleted uranium emits alpha and beta particles, and gamma rays. Alpha particles, the primary radiation type produced by depleted uranium, are blocked by skin, while beta particles are blocked by the boots and battle dress utility uniform (BDUs) typically worn by Service members. While gamma rays are a form of highly-penetrating energy , the amount of gamma radiation emitted by depleted uranium is very low. Thus, depleted uranium does not significantly add to the background radiation that we encounter every day.
When fired, or after "cooking off" in fires or explosions, the exposed depleted uranium rod poses an extremely low radiological threat as long as it remains outside the body. Taken into the body via metal fragments or dust-like particles, depleted uranium may pose a long-term health hazard to personnel if the amount is large. However, the amount which remains in the body depends on a number of factors, including the amount inhaled or ingested, the particle size and the ability of the particles to dissolve in body fluids.