Is Radium Lume Really That Dangerous?

 In Watch Basics

Many vintage watches have radium lume on the dial and in the watch hands. It’s a big part of the overall appearance and the charm of these vintage watches. Especially when the lume has changed into that attractive vintage yellow/brown color.

However, all over the internet are scary stories about radium, radioactivity, and the potential dangers.

Is radium lume really that dangerous or is it a tempest in a teapot?

A bit of history

In 1898, Pierre and Marie Curie discovered radium when they found out that the mineral uraninite was still radioactive after they’d removed the uranium.

Radioactivity was new and exciting. They had no idea that it was potentially dangerous. In fact, people thought that it was healthy and it was included as an ingredient in many products. Those products even included drinks and creams.

Is radium lume really that dangerous

Radior cream, because every woman deserves a beautiful glow

Watchmakers discovered that they could mix the radium with paint to create a paint that glows in the dark.

In the early 1900s, the dials and hands of nearly all timepieces were painted with this radioluminescent paint.

Almost all of the workers were women and they were told that the paint was absolutely harmless. They pointed their brushes on their lips to create a fine tip for the delicate work.

Several of the women got seriously ill and sued their employer for having contracted an occupational disease. These women are known as the Radium Girls.

The case was settled in 1928 and since that time, radium dial painters were provided with protective gear. Most importantly, they were forbidden to point the tip with their lips and they avoided to ingest or inhale the luminous paint.

Eventually, safer options were discovered and the use of radium was discontinued in the 1960s.

Radiation

Radium has a half-life of 1600 years. That means that the old radium on your watch dial and in the hands doesn’t glow anymore but it’s still radioactive.

It emits two types of radiation; alpha radiation and gamma radiation.

Alpha radiation

97% of the radiation is alpha radiation, also known as alpha particles.

These particles have such a large mass that they can only travel for a few centimeters and they’re easily absorbed. The watch crystal and the watch case(back) absorb all the alpha particles while wearing the watch.

The particles also can’t penetrate the epidermis so they’re absorbed by the skin without entering the body.

Alpha particles are highly dangerous inside the body though, because it kills and mutates cells. That’s why those poor radium girls got sick. They licked their brushes with luminous paint hundreds of times a day and ingested radium every time they did so.

Gamma radiation

3% of the radiation is the penetrating gamma radiation. Unlike alpha radiation, this type of radiation won’t be stopped by paper or plastic and it also penetrates the skin.

Tests have shown that a radium dial emits approx. 10uSv / hr. That means that you’ll have been exposed to a full day’s worth of background radiation in about 20 minutes. This is almost exclusively the gamma radiation because the alpha particles will have been blocked.

Decasing, removing the hands and dial and vice versa shouldn’t take more than 30 minutes. That means you’ll have been exposed to approx. a day and a half worth of background radiation as a watchmaker. While that’s not perfectly safe, it’s also not an immediate cause for concern.

What you might not have realized is that you’re exposed to the same level of radiation when you’re wearing the watch because gamma radiation requires a massive shield (a thick layer of lead for example) to be absorbed. You’ll actually be more exposed because you’ll likely wear a watch for more than 30 minutes at a time.

So, it’s not only the watchmaker who’s affected by the gamma rays but also the wearer.

Is radium lume really that dangerous?

Dial with radium of a Tiega watch

Radon

The gaseous decay product of radium is radon.

According to the United States Environmental Protection Agency, radon is the number one cause of lung cancer among non-smokers. In other words, it’s a serious health hazard. It also comes from natural sources and occurs as background radiation.

However, radon could only pose a threat in watches that are airtight, like divers. Many of the older dress watches are barely dustproof so there’s no way that gas could have built up.

If you suspect that radon might have built up over time, carefully remove the crystal in a well-ventilated room and let it cool down for a while.

Discontinued

The use of radium was discontinued since the 1960s. Omega stopped using radium around 1963.

Immediately after, substances like promethium and tritium were used as a luminous material and they’re still being used today.

Nowadays, Super-LumiNova, which is completely non-radioactive and non-toxic, is the most used lume in watchmaking.

Safety

As you can see, radium isn’t completely safe. That’s why the use of radium was discontinued in the 1960s.

But it’s also not as life-threatening as many claim it to be. Not a single factory worker got sick after they started wearing protective gear and stopped licking their paintbrush.

The biggest risk is inhalation or ingestion of radium because alpha particles are harmful inside the body. Old lume has often dried out and turned brittle so that’s certainly a risk when you want to relume the hands, for example.

Radium could still be hazardous. Always use protective clothing and use common sense.


What do you think of those old radium dials and hands? Let me know in the comments below.

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Showing 18 comments
  • Avatar
    Eugene
    Reply

    So, how much ionizing radiation would you expect to be dosed with if you wear a watch with old radium lume?

    • Melvin Hollenberg
      Melvin Hollenberg
      Reply

      I don’t know. It depends on the watch and how long you wear it. If someone really wants to know, a Geiger counter would be the best way of measuring it.

  • Avatar
    Sebastian Persson
    Reply

    You should still be really careful when handling radium watches that does not have any crystal on them. They do release a large amount of beta radiation and most can give off over 100uSv/h when they dont have the crystal over it. I own a lot of radium clocks and watches and one of the watches gives off 67uSv with the crystal on and another clock that I have does not have any crystal over it and it gives off 2130uSv! And thats not counting the alpha radiation. When putting my camera over it it starts to flash from the high radiation so always be careful and it is not recommended to tamper with the paint because it can still be hazardous and contaminate large areas.

    • Melvin Hollenberg
      Melvin Hollenberg
      Reply

      Thanks, Sebastian. It’s still potentially hazardous like you said. Always be careful, use protective clothing, and use common sense.

  • Avatar
    Al
    Reply

    My father was a watchmaker. I remember watching him apply new radium to watch hands. As children, my sister and I were always fascinated with how it glowed intently when we held the radium container under light. Recently I came across the little tin with a small a out of radium left in it. What would be a proper way to safely dispose of it?

    • Melvin Hollenberg
      Melvin Hollenberg
      Reply

      I always collect it to bring it to the recycling center.

      • Avatar
        Al
        Reply

        Is there a specific type of recycling center I should look for?

        • Melvin Hollenberg
          Melvin Hollenberg
          Reply

          We have one nearby for the municipality. The most important thing is that they’re equipped to dispose of radioactive waste. Better call them first.

  • Avatar
    Keith
    Reply

    I want to buy my first radium vintage watch. I’ll only wear it from time to time. What do people recommend..? I can spend about 500€

  • Avatar
    ANDREA
    Reply

    Read the book “The Radium Girls” and learn that radium is more dangerous than this article claims. It was not only the dial painters that became ill. Even family members (in one case a sister who shared a bed with her dial painter sibling) became ill. READ THE BOOK AND LEARN THE TRUTH. AS ALWAYS, BIG BUSINESS ONLY CARES ABOUT PROFITS, NOT PEOPLE.

    • Melvin Hollenberg
      Melvin Hollenberg
      Reply

      I’ve read Kate Moore’s book. It’s not safe, that’s why it was banned. But there’s no need to get hysterical about it. There’s a way to handle it safely with the proper protective clothing and procedures.

  • Avatar
    Kj
    Reply

    Hi,
    Thank you for this article.
    I bought a Steinhart watch one month ago (black military 42 model). It’s said to use “old radium” as lume. Do you know if it’s really made out of radium or is it a like-radium lume to make the whole more vintage?

    • Melvin Hollenberg
      Melvin Hollenberg
      Reply

      As far as I know, it uses the BGW9 SuperLuminova lume so it’s not radium. It should be whitish in daylight with a blue glow in the dark.

  • Avatar
    Joe
    Reply

    In 2009 I bought a 100% factory accurate fully restored 1961 (M1) Bulova Accutron Spaceview Alpha 14kt solid white gold from a reputable dealer. The luminous hands were advertised as new old stock . Do you have any experience with these watches to know if Bulova was still using Radium in 1961? It has been a concern of mine for quite some time particularly since I have to open the back of the watch to replace the battery from time to time. I guess I could buy a geiger counter but I was hoping someone might know the answer to this question.

  • Avatar
    Peter
    Reply

    Nice article. Most people are not aware how much 10 uSv/h is. It is equivalent to a dental Xray every hour.
    Do you have any tips to remove the paint from dials without destroying the paint?
    And how do you dispose of the radium?

    • Melvin Hollenberg
      Melvin Hollenberg
      Reply

      Hi, thanks. Everybody knows what a dental Xray is so thank you for clarifying. I try to keep away from the dial as much as possible because it’s very easy to accidentally remove varnish or lettering/markings. But if I had to, I’d use a toothpick or cotton swab with some alcohol. I collect tissues and cloths with old radium in a tin and I take it to the recycling point.

      • Avatar
        Eugene Velednitsky
        Reply

        I actually disagree with the usefulness of the above comparison. First of all, though many know what a dental x-ray is, they have little or no clear understanding of negative effects from the dose of radiation, nor do they realize that there is a massive difference between the various types of x-rays. For example, a standard chest X-ray has approximately 20 times the radiation dose of a dental x-ray. Secondly, when dose estimates are given for x-ray procedures, they are estimating the actual dose the patient receives, not the amount of radiation emitted from the source. As the particles are emitted from the radium markers in every direction, only a fraction of the total dose emitted is actually absorbed by the person wearing or working on the watch. So, with that stated. I do not personally know the exact dose of the radiation received by the wearer, I can safely say that there is likely a much better way of assessing the safety of it then saying it’s like dental x-rays.

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