Radium Clock Dials

In the early 1900s a new trend started in the world of time-telling: radium clock dials.

With this revolutionary glowing dial, those who purchased a clock or watch could enjoy the luxury of knowing the time in a dark room or during the middle of the night. Numbers on the dial were painted carefully with radium paint, allowing them to glow for long periods of time. Not only were these attractive timepieces a convenience, but they also provided thousands of new jobs, mostly for women.

Young and old women and even some men were employed by radium dial companies to hand-paint the dials; they were offered attractive weekly wages that were double or triple what they could earn elsewhere. Everyone was purchasing these must-have clocks and watches – until the dangers of radium were discovered in a horrific way.

Discovered in 1898 by the famous Marie Curie, radium is a pure white radioactive earth metal chemical element which also has the capability of turning black when oxidized. Radium caused quite a stir after its discovery and soon after in 1902, an American named William J. Hammer invented the first radium-based paint. By mixing a tiny bit of radium with paint, he discovered that the mixture was beneficial when used on watch dials and devices used in science. Soon after this the popularity spread through Europe and Switzerland in the timepiece industry. Not until 1914 did the the trend catch in the United States, when the first radium dial company opened in Newark, New Jersey. Popularity of radium dial clocks and watches grew in leaps and bounds; to meet demands many new companies opened and immediately each one hired plenty of new workers.

Radium, as it appears as item number 88 in the Periodic Table of Elements.

Young and old women and immigrants were enticed by the entrepreneurs who were eager to make a fortune by offering them a job painting radium dials. Without any knowledge of radium or radioactivity, these women and immigrants happily showed up for work every day, often painting over 100 dials. They were taught to lick the end of their paintbrush before carefully painting the tiny numerical digits on the dials. By licking the brushes they were ingesting small amounts of radium with each lick.

One of the most common types of paint used was called Undark. This paint consisted of zinc sulfide and radioactive radium. Ingested by thousands, this paint was used between 1917 and 1938 by the United States Radium Corporation. The few women who were skeptical about the paint were lightheartedly reassured by the supervisors that the paint was harmless and some were even told it would help their complexion, so some painted their nails and faces for fun; they were soon to find this statement was horribly untrue.

Undark Advertisement - an old ad for Undark Radium Paint for clock faces

In 1917 just a few years after the first U.S factory opened, the workers who painted dials soon found themselves suffering from the effects of radium poisoning. During their employment at the radium dial factories, they were unaware that many of the factory owners actually knew the radium was dangerous and were frequently and secretly testing their workers for levels of radioactivity. Those who tested positive for radioactivity were not informed.

Known in history as “The Radium Girls“, five of several affected women in Orange, New Jersey filed suit against The United States Radium Company in which they had worked. Various effects were seen in the women who became radioactive; anemia set in first, often followed by bone fractures and jaw deterioration called Radium Jaw.

In the condition known as Radium Jaw, both the upper and lower jawbones would deteriorate and grow tumors, causing facial distortion, loss of teeth, gum tissue and even sections of the jawbones. One woman named Peg Looney contracted radium poisoning in 1925 and again three years later, but her family was unaware of this until after her death in 1929. They recounted episodes in her last years where she would actually pull pieces of her decaying jaw and teeth from her mouth with ease. While the term “Radium Girls” refers to those employed by the factory in Orange, New Jersey, many other workers all over the world died of radium poison’s effects.

By 1930 radium dial painters were ordered not to paint their fingernails or skin with the radium and more importantly not to lick their paintbrushes to sharpen them. This practice soon showed the rates of poisoning to decrease and incidences had diminished completely by 1950. The sale of radium dials fell after news of this harmful substance spread, but they were still manufactured and sold. In fact, timepieces with radium dials were still made for years after, but not in as large of numbers. When word spread about radium, many consumers refused to purchase these clocks and watches anymore. Any dial made with radium after 1950 was marked with “Ra” or “R”, indicating the presence of radium paint on the dial.

Thankfully, today radium dial timepieces are something no longer found on store shelves!

Some antique dealers may carry these items but if they are aware of the radium, they usually keep them in glass cases where they’re safe. The only place to find them regularly is on sites such as eBay, where a small handful of auctions may be found for vintage radium clocks and watches sometimes. Only timepiece collectors usually buy these items, as cleaning them may be very difficult. Most radium paints used on these clocks have a life of about 40 to 50 years before the paint crumbles and becomes a powder which is harmful if swallowed or inhaled; the fine dust coming off the face of an open radium dial would be a hazard to any human.

Those who are concerned about radium dial timepieces should wait before throwing out any and every glowing clock or watch – not all glowing dials are harmful. But if you’ve done you’re research about radium clock dials and have read this article and followed our advice, and you still suspect that a clock of yours has a radium dial, then please, be on the safe side and have it disposed of!

Radium dials may be identified by how long they glow for. Even the dust and powder from decayed paint will glow.

To test a dial for radium, a person should leave the dial facing direct light, then shut the light off and check the dial frequently. While most glowing dials only glow for a short time, radium clocks may glow for hours afterwards. If a clock or watch has cracked letters or a decrepit look to the paint on the letters, it should also be disposed of.

Should the timepiece break and the powder be allowed to spill, the dangers of cleaning it up are more than the timepiece is worth. Disposal of radium must be done by contacting your local hazardous waste department.

Editorial Cartoon about the Radium Girls from the American Weekly, February 28, 1926

Those who choose to keep their radium dial clocks for nostalgic value should keep them in sealed plexi-glass casings in a safe location.

We at the Online Alarm Clock were sad during our research into this particularly dark hour in clock history.

Our sympathies go out to all the friends and family of The Radium Girls and anyone else who’s been affected by radium poisoning! We hope their undeserved deaths will not become forgotten.

Tags: clock history, radium clock dials, radium dial company, radium dial painters, radium dials, radium girls, radium jaw, radium paint, radium poisoning, undark, united states radium corporation