For much of the twentieth century the United States Department of Defense was a major production of radioactive waste. The Pentagon not only produced its own nuclear waste. For years, the Pentagon depended on an unknown number of private defense contractors to supply countless radioactive parts and equipment. In the mid-twentieth century, the U.S. government actually gave some of these defense contractors permission to dump radioactive waste on their private properties. The Pentagon seldom, if ever, disclosed the whereabouts of these dangerous nuclear dumps. The problem becomes one for the ages: many of these radioactive isotopes remain dangerous and "hot" for thousands of years, even as the radiation is invisible to unsuspecting victims.