ARPANSA - Australian Radiation Protection and Nuclear Safety Agency

Following the discovery of radium by Pierre and Marie Curie in the early 20th century, it was quickly realised that the luminescent properties of radium made it useful on watch and clock faces, as it made them easy to read in the dark. Paint containing small quantities of radium-226 has been used since the early 1920’s on the hands and numerals of wrist watches.

Although the scientific literature contains many stories about the high rate of cancer among the women employed as dial painters, the radiation risk associated with wearing a standard wrist watch is extremely small.

Radium emits alpha radiation and gamma radiation. The alpha radiation carries most of the energy, but is only hazardous when taken into the body by inhalation or ingestion, or through open wounds. Gamma radiation is more of an external hazard, but there is only a small amount of radium on the face of a typical wrist watch, and the back of the watch (next to the skin) is protected by a metal or plastic case.

The problem with the dial painters occurred because watch faces are very small, and the dial painters had the habit of licking the tips of their brushes to make a fine point, so that the paint would go where it was wanted. As a result of this practice, which was carried out for a number of years, most of the cancers suffered by the dial painters were cancers of the jaw, mouth and throat.

Other non-radioactive substances are now used in modern watches to make them visible in the dark. The wearing of older wrist watches that do contain luminescent radium paint is not regarded as any form of health hazard.

 

 

 

 

 

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