…are a particularly nasty ‘dirty bomb’ that will contaminate an area for a lifetime and kill all living things. Theoretically, a number of these could kill all life on Earth as the fallout spreads around. It’s a real ‘scorched earth’ doomsday weapon. Why anyone would use it is insane. It’s never been tested, but is easily accomplished by adding a cobalt jacket to a fission bomb.
http://rense.com/general40/dooms.htm