The Radium Girls were female factory workers who contracted radiation poisoning from painting radium dials – watch dials and hands with self-luminous paint. The incidents occurred at three factories in the United States: one in Orange, New Jersey, beginning around 1917; one in Ottawa, Illinois, beginning in the early 1920s; and one in Waterbury, Connecticut, also in the 1920s.
Radium painters working in a factory
Former factory site in West Orange, New Jersey
Radium dials are watch, clock and other instrument dials painted with luminous paint containing radium-226 to produce radioluminescence. Radium dials were produced throughout most of the 20th century before being replaced by safer tritium-based luminous material in the 1970s and finally by non-toxic, non-radioactive strontium aluminate–based photoluminescent material from the middle 1990s.
A 1950s radium clock, exposed to ultraviolet light to increase luminescence
November 1917 ad for an Ingersoll "Radiolite" watch, one of the first watches mass marketed in the USA featuring a radium-illuminated dial.
Wristwatch produced for the US Army during World War II showing characteristic sandy deterioration of radium–zinc sulfide painted hands and numbers. Such a watch should not be opened due to the danger of inhalation of airborne particles.
Three radium dials and a radon detector are placed in a sealed plastic container. After 6 hours, the radon level was 446 pCi/L.
