The Waterbury Clock Company experienced an increased demand for watches after the First World War, and to turn a profit, they hired women at low wages to work seven days a week.
The company called for women with “nimble fingers” to paint the dials and numbers onto watches in assembly-line fashion. To speed up the process, women would “lip-dip,” meaning that they placed the paintbrush into their mouths and then dipped the brush into the radium-laced paint. Repeating this process caused the radium to linger in their mouths.
Initially, the women did not know the risks of radium and even enjoyed painting it onto their nails and clothing to glow in the dark, but exposure to radium later led to over 30 deaths in the company.