When fourteen-year-old Katherine Schaub started work at the watch-dial factory of the Radium Luminous Material Corporation in Newark, New Jersey, in February 1917, she thought she was the luckiest girl in the world. Her new job, applying the numbers to watch dials in luminous paint, would be hard work, requiring diligence and a steady hand, but it promised to pay well and the other girls were welcoming and would become friends. More than that, though, there was the glamour of working with radium: the so-called ‘watch studio’ looked as if it had been sprinkled with stardust.

Discovered by Marie and Pierre Curie only nineteen years earlier, radium was a wonder element. At $120,000 a gram it was the most valuable substance on earth and had been hailed as a miracle cure that could wither cancerous tumours and restore vitality to the old. Even its name made it sound as if those in contact with it would actually become radiant. ‘Sometimes I am halfway persuaded that I can feel the sparkles inside my anatomy,’ claimed one happy user with unconscious insight.

At the studio, tiny particles of radium used in the luminous paint made everything gleam. The girls were covered with a fine layer of dust that infiltrated their clothes and clung to their hair and skin and particularly their lips, since they repeatedly wet the tips of their slender brushes