This caused some caesium-137 from a measuring instrument to be included with eight truckloads of scrap metal on its way to a steel mill, where the radioactive caesium was melted down into the steel.
The salts of caesium are also soluble in water, and this complicates the safe handling of caesium. Test explosions "Simon" and "Harry" were both from Operation Upshot–Knothole in 1953, while the test explosions "George" and "How" were from Operation Tumbler–Snapper in 1952 Caesium-134 and caesium-137 were released into the environment during nearly all nuclear weapon tests and some nuclear accidents, most notably the Chernobyl disaster and the Fukushima Daiichi disaster.
Cobalt-60, , is preferred for radiography, since it is chemically a rather nonreactive metal and produces higher energy gamma-ray photons. As of 2005 and for the next few hundred years, caesium-137 is the principal source of radiation in the zone of alienation around the Chernobyl nuclear power plant.
By the end of 2014, "Fukushima-derived radiocesium had spread into the whole western North Pacific Ocean", transported by the North Pacific current from Japan to the Gulf of Alaska.
It has been measured in the surface layer down to 200 meters and south of the current area down to 400 meters.
By observing the characteristic gamma rays emitted by this isotope, one can determine whether the contents of a given sealed container were made before or after the first atomic bomb explosion (Trinity test, 16 July 1945), which spread some of it into the atmosphere, quickly distributing trace amounts of it around the globe.
This procedure has been used by researchers to check the authenticity of certain rare wines, most notably the purported "Jefferson bottles".
is the Goiânia accident of 1987, in which an improperly disposed of radiation therapy system from an abandoned clinic in the city of Goiânia, Brazil, was removed then cracked to be sold in junkyards, and the glowing caesium salt sold to curious, unadvised buyers.
This led to four confirmed deaths and several serious injuries from radiation contamination.
As a man-made isotope, caesium-137 has been used to date wine and detect counterfeits A 1972 experiment showed that when dogs are subjected to a whole body burden of 3800 μCi/kg (140 MBq/kg, or approximately 44 μg/kg) of caesium-137 (and 950 to 1400 rads), they die within 33 days, while animals with half of that burden all survived for a year. Together with caesium-134, iodine-131, and strontium-90, caesium-137 was among the isotopes distributed by the reactor explosion that constitute the greatest risk to health.