Many old vintage watches—especially military watches—have gold or white-ish colored paint on their hands or the numbers on their dials.
This paint could potentially be made of a phosphorescent compound mixed with radium.
This compound would cause the hands/numbers to glow in the dark. This type of mixture was often chosen over others because of the superiority of its glow and longevity.
Unlike any other glow-in-the-dark paints, the radium-mixed paint could glow through an entire night (where other paints would lose their glows as the night progressed) and could potentially continue to glow for many years.
The problem with vintage radium-painted watches was that their “glow” came from the radioactive decay of the radium itself, which had the very serious potential to cause various health problems to those who handled them frequently.

Identifying a Radium Watch
There are a couple ways to identify a radium-painted watch.
One is to look for an “R” or “Ra” located on the dial below the six o’clock marker. Beginning around the 1950s or ’60s, watches dials began to be labeled this way in order to distinguish the element used in its markers.
Similarly, a watch featuring tritium in its paint during this time would also be marked with two small Ts, or T<25 labels near the same six o’clock marker. The “<25” label signified that the watch included less than 25 millicuries of radioactive tritium.
The use of a Geiger counter or dosimeter to measure any present radiation levels.
These instruments will be able to pick up the radiation of a vintage radium-painted watch, but will not be able to detect other, non-radioactive glow-in-the-dark compounds, or tritium-painted compounds.
You can also make an educated guess concerning the age of the watch; the older the watch, the more likely it is to contain radioactive material.

Radium Girls
Radium was used in watch paint beginning around 1910 well before the danger of radioactivity began to be understood. After World War I and through the 1920s, radium-painted dials became very popular for both watches and clocks.
Companies that produced radium-painted watch and clock dials, and other instruments typically hired young women to do the painting, and generally failed to disclose to them the potential hazards of working with the radioactive material.
While scientists and the owners of the U.S. Radium Corporation were well aware of the potential harm of interacting with radium, much of the rest of the population was lead to believe the opposite.
Radium was touted as a new miracle compound with fantastic medical potential—it was even believed to be a stomach cancer cure. Because of all this, workers were unsurprisingly given little-to-no warning of the health dangers of handling such radioactive materials.
Workers were often encouraged to lick the tips of their paintbrushes in order to keep the tips pointed for more accurate painting, which resulted in many workers continually ingesting small amounts of radioactive material each workday.
When the dangers of radioactive paint began to receive media attention in the 1920s after numerous workers began to fall ill from unknown causes, investigations into the working environments of these companies showed just how lax their regard for the safety of their workers was.
In 1927 Raymond Berry, a New Jersey attorney, filed a lawsuit against U.S. Radium on behalf of Grace Fryer, a former U.S. Radium employee stricken with radium poisoning.
Soon thereafter four other women with similarly severe medical problem were added to the lawsuit, which asked for $250,000 for the medical expenses and pain of the women.
Sensationalist newspapers quickly latched onto the court case due to the large popularity of radium-infused health products at the time and began referring to the five women as the “Radium Girls.”
After being delayed by U.S. Radium for months, the company eventually settled with the five women, agreeing to pay $10,000 and $600 per year in annuity to each woman while they lived, as well as all their legal and medical expenses.
Although the women “won” their case, they all inevitably died from their earlier exposures to radium.

Risks of Radium
Ingesting and inhaling radium dust are the main ways to contract illnesses associated with radium poisoning, although making any sort of bodily contact with radium-infused materials can be harmful.
Contact with radium can cause different bone diseases and cancers, as well as a host of other problems.
Radium that is breathed in, however, may be settled in the lungs to cause lung damage in addition to being absorbed into the bloodstream.

Mark Sirianni Watch Repair
25 Fraley Street
Kane, Pa. 16735
814-837-9435
814-558-4818 (cell)
watchdoctorpa@gmail.com

CHARLEY PHOTO OF THE WEEK: Charley is hard at work defending the back yard from trespassers and bunnies.

12 Comments
Tom Gonzales
Very interesting! My best friend and watchmaker, Mark Gerrish who died from ALS in 2018 actually had several very old cans of the stuff in his vast array of stock inventory. As I remember, he also had some tubes of paint that he would use to “refresh”, “glow in the dark” dials on some of the older watches he worked on. Boy, am I glad I never messed with any of that stuff. You did a great job Mark, and please continue the good work! Oh, and by the way, that Hamilton 992B that you overhauled for me has kept perfect time for nearly three months without any adjustment. Just want you to know that it is still within 55 seconds of the atomic clock on the wall. Thank You!!
Len. (UK)
Sounds like yet another case of “history tepeating itself.”
The corona vaccine, with it’s possible danger to health, has not been tested…………..merely rolled out and shoved in!
Len. (UK)
Sounds like yet another case of “history repeating itself.”
The corona vaccine, with it’s possible danger to health, has not been tested…………..merely rolled out and shoved in!
Jim
In the 1980s I went to work for EG&G at plant that made special switches that contained radio active material. In my desk I found an old glow in the dark watch mixed in with some of the switches. I inquired as to why my predecessor had it. I was told that when the women were afraid of the switches that they worked on, he would show them with a Geiger counter that the switches had less radiation than the watch.
Mark Morgan
Great information thank you
Melissa Johnson
Very scary & sad, yet such an informative article. I had no idea of this. I learn something every time I open your emails. Thank you!
Have a great day, you, Charley & family stay warm!
Miami Mike
Many older aircraft instruments also used radium on the dials and hands. Anyone working on vintage military aircraft will encounter this. There are specific (and expensive) procedures to deal with these instruments, and there are no modern replacements. Most instrument repair shops won’t touch them any more. That’s why you sometimes see WW2 vintage aircraft with modern glass panels installed. The new stuff works better, too.
Johnny
Great informative article. Charley looks raring to go.
Mel Schuman
A well written, important paper. Thank you for the information.
Julio Leblanc
Great info Mark. Keep up the good work. I will always send my Rolex watches to you for repair and overhaul. My stainless Sub has been working perfectly since you overhauled it several years ago at such a reasonable price. Thank you so much! Julio
Alan Brody
There was never any danger to someone wearing the watch, even wearing it every day there was not enough exposure. It’s hard to imagine a danger to anyone from these watches today. As Mark wrote, the danger was from people swallowing tiny amounts of radium many times each day for years. I don’t know how big the paint containers they dipped their brushes in were, but with a lot of those around a crowded room that could have been an exposure risk too.
Most radium dials no longer glow, but that’s because of changes in chemicals in the paint, not because the radium is no longer radioactive. The half life of radium is 1600 years, so after 100 years it still has 95% of the radioactivity it did when the watch was new.
Mike Graves
Very important historical data, Mark. Thank you very much. We should never forget incidents like these.