It seems believable given the story of the “Radium Girls”, workers who painted radioactive paint on watch dials to make them glow. They’d lick the tips of the brushes when they got too frayed… which eventually led to cancer.
A department store still had one of these when I was a kid, but it wasn't used. It was, however, in occasional use when my brother was very little in the early 80s. My mom has pictures of him with his foot in it.