DEPLETED URANIUM (aka DU or U238)

Naturally occurring uranium contains mostly two isotopes: U238 (about 99.2745%) and U235 (about 72%). The U235 isotope fuels the chain reaction in weapons and reactors. The process of enrichment concentrated the amount of U235 in fuel and bomb material. The U238 left behind is referred to as Depleted Uranium, since it has been depleted of its U235.

Although unable to sustain chain reactions like U235, DEPLETED URANIUM (U238) is very radioactive and also is a toxic heavy metal, with "a toxicity on par with lead arsenate, and more dangerous than phosgene or arsenic" according to online sources.

Being a very heavy metal - denser than lead - it turns out to be very effective as a material for the tip of warheads. Weapon designers also love the fact that after impact it is pyrophoric - meaning it bursts into flame. After an impact, this spreads a fine dust of toxic, radioactive uranium dioxide dust..

US forces have measured DU fragments in the Gulf emitting up to 250 millirads of radiation per hour (exceeds recommended US annual radiation dose in under 30 minutes), and the US military are on record as confirming activity levels of 2.5mGy/hr at the surface of a DU shell.

An excellent overview of current science about DU can be found at: