Cobalt Bombs

Leo Szilard originated the idea of the use of Cobalt 59 in nuclear weapons in February 1950 to demonstrate that in theory it would be possible to build a weapon with the capability of killing everyone on earth. Cobalt 60 is an ideal radioactive isotope because it could be dispersed worldwide before decaying and its half-life would make this possible. To public knowledge, no such bomb has actually ever been atmospherically tested or built. However, the UK tested a bomb which incorporated cobalt as an experimental radiochemical tracer on 14 September 1957 at its test site in Maralinga, Australia.