"Radium Girls" refers to a group of female factory workers in the early 20th century who painted watch dials with luminous paint containing radium. These women were often instructed to use their lips to shape the brushes, leading to severe health issues due to radium exposure. The plight of the Radium Girls highlighted the dangers of industrial work and the lack of safety regulations. Their struggle for justice against their employers eventually contributed to changes in labor laws and workplace safety standards, raising awareness about the rights of workers and the importance of protecting public health.