Radium Girls were a group of female factory workers who contracted radiation poisoning from painting watch dials with glow-in-the-dark paint at the United States Radium factory in Orange, New Jersey around 1917.
An estimated 4,000 workers were hired by corporations in the U.S. and Canada to paint watch faces with radium. They mixed glue, water and radium powder, and then used camel hair brushes to apply the glowing paint onto dial numbers. The going rate, for painting 250 dials a day, was about a penny and a half per dial. The brushes would lose shape after a few strokes, so the U.S. Radium supervisors encouraged their workers to point the brushes with their lips, or use their tongues to keep them sharp. For fun, the Radium Girls painted their nails, teeth and faces with the deadly paint produced at the factory, sometimes to surprise their boyfriends when the lights went out.