Salted bomb A salted bomb is a Radiological weapon designed to produce enhanced quantities of radioactive fallout , rendering a large area uninhabitable . The term is derived both from the means of their manufacture , which involves the incorporation of additional elements to a standard atomic weapon , and from the expression " to salt the earth " , meaning to render an area uninhabitable for generations . The idea originated with Hungarian - American physicist Leo Szilard , in February 1950 . His intent was not to propose that such a weapon be built , but to show that nuclear weapon technology would soon reach the point where it could end human life on Earth . No salted bomb has ever been atmospherically tested , and as far as is publicly known none have ever been built . A salted bomb should not be confused with a " dirty bomb " , which is an ordinary chemical explosive bomb containing radioactive material which is spread over the area when the bomb explodes . A salted bomb is able to contaminate a much larger area than a dirty bomb . Design . Salted versions of both fission and fusion weapons can be made by surrounding the core of the explosive device with a material containing an element that can be converted to a highly radioactive isotope by neutron bombardment . When the bomb explodes , the element absorbs neutrons released by the nuclear reaction , converting it to its radioactive form . The explosion scatters the resulting radioactive material over a wide area , leaving it uninhabitable far longer than an area affected by typical nuclear weapons . In a salted hydrogen bomb , the radiation case around the fusion fuel , which normally is made of some fissionable element , is replaced with a metallic salting element . Salted fission bombs can be made by replacing the neutron reflector between the fissionable core and the explosive layer with a metallic element . The energy yield from a salted weapon is usually lower than from an ordinary weapon of similar size as a consequence of these changes . The radioactive isotope used for the fallout material would be a high intensity gamma ray emitter , with a half - life long enough that it remains lethal for an extended period . It would also have to have a chemistry that causes it to return to earth as fallout , rather than stay in the atmosphere after being vaporized in the explosion . One example of a possible salted bomb would be a cobalt bomb , which would produce the radioactive isotope cobalt - 60 ( Co ) . Other radioactive isotopes that have been suggested for salted bombs include gold - 198 ( Au ) , tantalum - 182 ( Ta ) and zinc - 65 ( Zn ) . Sodium - 24 has also been proposed as a salting agent . The UK tested a 1 kiloton bomb incorporating a small amount of cobalt as an experimental radiochemical tracer at their Tadje testing site in Maralinga range , Australia , on September 14 , 1957 . In popular culture . This concept is best known from the Soviet " Doomsday Device " in the 1964 satirical Cold War film " Dr . Strangelove " . In the 1957 novel " On the Beach " by Nevil Shute , the death of all humanity is brought about by the detonation of cobalt bombs in the Northern Hemisphere . The 1970s movie " Beneath the Planet of the Apes " featured an atomic bomb that was hypothesized to use a cobalt casing . The use of a salted bomb is a component to the plot of Frank Miller ' s graphic novel series " The Dark Knight Returns " .