Who where the radiant girls?

The radiant girls were a group of girls hired to paint glow-in-the-dark numerals on watches in the mid 1920's, they were told to keep the paint brushes pointy by licking them after every stroke, what they didn't know was that the chemicals in the glow-in-the-dark paint was harmful if ingested slowly all of the radiant girls began to fall ill with bone cancer and eventually deceased