According to Caldicott, up to 70% of the uranium released when DU munitions are exploded is converted into microscopic particles that can be inhaled or ingested immediately or when air, soil and water get contaminated. Once inside the human body, these particles kill or mutate the cells they come in contact with. Photographs of DU particles in living lung tissues show them as tiny sun-like, radiating objects. The half-life of this radioactive substance is 4.5 billion years.