In 1955, Charles E. Miller and L. D. Marinelli were measuring human
potassium levels with the whole body counter at the Argonne laboratory.
They were puzzled by finding several people who emitted 0.660-Mev gamma
rays. Gamma rays of this energy, which are emitted by cesium-137, had
not previously been detected in humans. To add to the perplexity, when
the same persons were examined a few months later, the count of these
gamma rays had increased. The Argonne findings indicated strongly that
radiocesium, which is known to occur in fallout from nuclear explosions,
was finding its way into people’s bodies. (See _Fallout from Nuclear
Tests_, another booklet in this series.)