Depleted Uranium - banned by UN used by The US

The use of DU in munitions is controversial because of questions about potential long-term health effects. Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by uranium exposure, because uranium is a toxic metal. It is weakly radioactive (nevertheless definitely a cancerogenic and causes genetic mutation, disrupts DNA) and remains so because of its long radioactive half-life (4.468 billion years for U-238, 700 million years for U 235). The biological half-life (the average time it takes for the human body to eliminate half the amount in the body) for uranium is about 15 days. The aerosol or spallation frangible powder produced during impact and combustion of depleted uranium munitions can potentially contaminate wide areas around the impact sites, leading to possible inhalation by human beings, rendering the site inhibitable forever.