|MadSci Network: Physics|
Several radioactive materials have been used to illuminate watches, however radium was the only substance used for the purpose in 1925. I was unable to find documented evidence of harm due to wearing radio-luminescent watches or having radio-luminescent clocks in the home. I did find one anecdotal account of a neoplasm (an abnormal growth, possibly a precursor to cancer) occuring on the wrist of a man who wore a radium-dialed watch for many years. Given the information above, I would have to say that wearing a radium-dialed watch is essentially risk-free. However, during the manufacture of radium-dialed watches, clocks, and gauges in the early days of this century (in the 'teens and twenties), several dozen people (mostly young women) were seriously injured or killed when they ingested large quantities of radium (much much larger quantities than could be found on one watch or clock alone). An excellent historical reference for the uses and risks of radioactive materials is "Radioactivity and Health: A History" by J. Newell Stannard (ISBN 0-87079-590-2, or microfiche 0-87079-591-0). It's pretty expensive, but any competent technical library should have one. Also, a great source of reliable information on anything that radiates or is radioactive is the Health Physics Society. Their website is http://www.hps.org/ and contact information and a list of local chapters is available by calling (703) 790-1745. Unfortunately, there is a lot of dis-information out there about anything radioactive, so anything you find 'surfin' the net' should be taken with a grain of salt.
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