What's the "een" in Halloween?
Radioactive materials that may be left after a commercial or laboratory process has been carried out. Some is “low-level” waste, such as objects that have touched the radioactive tracers used in certain medical tests. Other waste may be “high-level,” such as the material left in a nuclear reactor after the fuel has been consumed.
Note: There has been public debate over the safest means of storing the waste, which can remain dangerously radioactive for up to hundreds of thousands of years. Present practice calls for encasing the waste in metal, concrete, and ceramic containers and burying the containers deep underground in geologically stable locations.