In the 1910s and 1920s, young women across the United States took jobs painting glow-in-the-dark numbers on watches and military dials. The paint contained radium, a newly discovered element that gave off a ghostly green glow—and was believed to be harmless, even healthy.

To keep their brushes fine, workers were told to “lip-point” them—placing the bristles between their lips after each dip. They were encouraged to do this dozens of times per day.

Over time, the women began to suffer agonizing symptoms: bone fractures, progressive bone damage in the face and mouth, anemia, and fatal cancers. Doctors were baffled, and the companies denied any connection to the paint.

They were called the Radium Girls and some of them refused to be silenced. In the face of legal threats and public skepticism, a few brave women sued the corporations—and won. 

Their fight led to groundbreaking labor protections and helped establish workplace safety standards we still rely on today.