All nuclear materials remain highly toxic for thousands of years.
Man-made radiation is more toxic to humans than naturally occurring radiation even if the dose is the same. The human body has the capability to repair damaged caused by exposure to radiation. In the US, most cases of cancer in humans are known to be caused by man-made radiation. I would rather live within a 50 mile radius of a coal-burning plant than a nuclear power plant. One of the chief dangers from nuclear power plants is that they can explode like a nuclear bomb.