ARE RADIUM WATCH
DIALS DANGEROUS?

A watch is only as good as its ability to tell you the time. This means that early watches, however finely made or accurate, were daytime timepieces. Before widespread public and domestic lighting, ‘night’ meant dark until morning. A chiming clock might mark passing hours if you were rich or close enough to a church. Chiming watches, known as repeaters, were only available to the privileged rich.

The substance that put the ‘time’ into night-time was discovered by Marie and Pierre Curie in 1898. Radium is a curious element, consistently warmer than its surroundings due to the radiation it emits, but what suited it to watchmaking was the fact that it glowed. This meant it could be used to impregnate the hands and dials of watches and clocks, making them glow at night. Luminous paint was invented in 1902 by William J Hammer, who first mixed radium with zinc sulphide, but he failed to patent his creation and lost out to George Kunz at Tiffany & Co., who did.

Radiation can seriously affect human health, and these effects vary depending on the type of particle emitted. All radiation has an ionising effect, changing the chemical composition of cells, damaging them, and even leading to cancer.

There are three major types of radiation to consider here:

1. Alpha particles:
Alpha particles cannot penetrate most matter. A piece of paper or the outer layers of skin is sufficient to stop alpha particles.

Radioactive material that emits alpha particles (alpha emitters) can be very harmful when inhaled, swallowed, or absorbed into the bloodstream through wounds.

2. Beta particles:
Beta particles can be stopped by a layer of clothing or a few millimetres of a substance such as aluminium.

Beta particles are capable of penetrating the skin and causing radiation damage, such as skin burns.
As with alpha emitters, beta emitters are most hazardous when they are inhaled, swallowed or absorbed into the bloodstream through wounds.

3. Gamma rays and X-rays:
Gamma rays and X-rays are penetrating. Several feet of concrete or a few inches of
lead are required to stop them.

Gamma rays and X-rays are a radiation hazard for the entire body. While gamma rays and X-rays can easily pass completely through the human body, some fraction of the energy will always be absorbed by body tissue.

The hazardous consequences of Radium were identified only two years after its discovery. Despite this, the early 20th century saw an outbreak of ‘Radium Fever’. As with former discoveries such as magnetism and electricity, it was offered as a health-giving cure-all. Radium-laced toothpaste, face cream and even underpants were sold, all with dreadful effects.

Early use of radium paint was most widespread in Switzerland where, to quote Ross Mullner – author of ‘Deadly Glow’, “there were so many radium painters in that country that it was common to recognise them on the streets even on the darkest nights because of the glow around them: their hair sparkled almost like a halo.”

The USA began using radium paint in 1914, bringing its toxic effects to the workplace. In the case of the ‘Radium Girls’, women who worked at three dial-making facilities were told that the luminous paint was harmless by their managers. In addition to daubing each other for fun, they pointed their brushes for delicate work by licking the bristles. In doing so, they ingested lethal amounts of radium.

Using brushes in this way, a practice derived from ceramic painting, was rare in Europe where glass pens or wooden styluses were used. The manufacturers denied liability and suppressed medical evidence accusing some of the victims of contracting syphilis. Eventually, the women proved their case and the fact that the management knew of the risks. Radium continued to be used until the 1960s, but with new safety measures being followed, workplace contamination stopped.

It is unusual for collectors to focus on watches with radium dials and hands, but an interest in vintage watches from 1910 to 1960 will inevitably bring such watches into consideration. The distinctive blackened lume dots and star-burst dial ‘burn’ of this Rolex Oyster Perpetual 14ct Model Ref. 6084 from 1952 show the untouched originality of the watch that collectors appreciate. Many military watches had their luminous material changed from radium to tritium at service, so to find a watch in its original condition is more rare and valuable.

Unless you are a WWII MOD Quartermaster, or your vintage watch collection is enormous, the risk of storing several vintage radium dials watches together is negligible. Still, the presence of radon gas is an important consideration.

Radon Gas

Radon is a colourless, odourless gas that is the natural product of radioactive decay. It occurs as small amounts of uranium naturally found in rocks, such as granite, decay. The decay of radium also produces radon. It is a radioactive material in its own right, and being a gas can easily be inhaled or ingested. In nature, concentrations rarely build to harmful levels, but stagnant air trapped underneath houses can cause problems as levels build. Long-term radon exposure can lead to breathing problems and lung cancer.

The active radium in the dial and hands of a vintage watch produces radon in small quantities. This will leak out of the case as they are not hermetically sealed. The solution to radon in houses is good ventilation. Houses in badly affected areas have small fans installed in basement areas to circulate the air and prevent radon build-up. If you store several vintage watches together in a box or safe, it is a good idea to open the door regularly and take them out. This will disperse any radon and prevent health problems. While you have your watch out, why not take the opportunity to wear and appreciate it?