Uranium in the environment resulting in workers exposed to high levels of radiation. Conventional uranium ore treatment mills create radioactive waste in the form of tailings, which contain uranium, radium, and polonium. Consequently, uranium mining results in "the unavoidable radioactive contamination of the environment by solid, liquid and gaseous wastes". Inhalation of radon gas caused sharp increases in lung cancers among underground uranium miners employed in the 1940s and 1950s. In the 1940s and 1950s, uranium mill tailings were released with impunity into water sources, and the radium leached from these tailings contaminated thousands of miles of the Colorado River system. Between 1966 and
Depleted uranium Depleted uranium has been used in a number of sampling calorimeters (such as in the D0 and ZEUS detectors) due to its high density and natural radioactivity. Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by uranium exposure because, in addition to being weakly radioactive, uranium is a toxic metal, although less toxic than other heavy metals, such as arsenic and mercury. It is weakly radioactive but is 'persistently' so because of its long half-life. The Agency for Toxic Substances and Disease Registry states that: "to be exposed to radiation from uranium, you