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Undark was a trade name for luminous paint made with a mixture of radioactive radium and zinc sulfide, as produced by the U.S. Radium Corporation between 1917 and 1938. It was used primarily in radium dials for watches and clocks. The people working in the industry who applied the radioactive paint became known as the Radium Girls because many of them became ill and some died from exposure to the radiation emitted by the radium contained within the product. The product was the direct cause of radium jaw in the dial painters. Undark was also available as a kit for general consumer use and marketed as glow-in-the-dark paint.
Mixtures similar to Undark, consisting of radium and zinc sulfide, were used by other companies. Trade names include:
Radium is a chemical element; it has symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) upon exposure to air, forming a black surface layer of radium nitride (Ra3N2). All isotopes of radium are radioactive, the most stable isotope being radium-226 with a half-life of 1,600 years. When radium decays, it emits ionizing radiation as a by-product, which can excite fluorescent chemicals and cause radioluminescence. For this property, it was widely used in self-luminous paints following its discovery. Of the radioactive elements that occur in quantity, radium is considered particularly toxic, and it is carcinogenic due to the radioactivity of both it and its immediate decay product radon as well as its tendency to accumulate in the bones.
An incandescent gas mantle, gas mantle or Welsbach mantle is a device for generating incandescent bright white light when heated by a flame. The name refers to its original heat source in gas lights which illuminated the streets of Europe and North America in the late 19th century. Mantle refers to the way it hangs like a cloak above the flame. Gas mantles were also used in portable camping lanterns, pressure lanterns and some oil lamps.
Ebenezer McBurney Byers was an American socialite, sportsman, and industrialist. He won the 1906 U.S. Amateur in golf. He died from jawbone cancer after consuming Radithor, a patent medicine made from radium salts dissolved in water.
Tritium radioluminescence is the use of gaseous tritium, a radioactive isotope of hydrogen, to create visible light. Tritium emits electrons through beta decay and, when they interact with a phosphor material, light is emitted through the process of phosphorescence. The overall process of using a radioactive material to excite a phosphor and ultimately generate light is called radioluminescence. As tritium illumination requires no electrical energy, it has found wide use in applications such as emergency exit signs, illumination of wristwatches, and portable yet very reliable sources of low intensity light which won't degrade human night vision. Gun sights for night use and small lights used mostly by military personnel fall under the latter application.
The Radium Girls were female factory workers who contracted radiation poisoning from painting radium dials – watch dials and hands with self-luminous paint. The incidents occurred at three factories in the United States: one in Orange, New Jersey, beginning around 1917; one in Ottawa, Illinois, beginning in the early 1920s; and one in Waterbury, Connecticut, also in the 1920s.
Radioactive quackery is quackery that improperly promotes radioactivity as a therapy for illnesses. Unlike radiotherapy, which is the scientifically sound use of radiation for the destruction of cells, quackery pseudo-scientifically promotes involving radioactive substances as a method of healing for cells and tissues. It was most popular during the early 20th century, after the discovery in 1896 of radioactive decay. The practice has widely declined, but is still actively practiced by some.
Radioluminescence is the phenomenon by which light is produced in a material by bombardment with ionizing radiation such as alpha particles, beta particles, or gamma rays. Radioluminescence is used as a low level light source for night illumination of instruments or signage. Radioluminescent paint is occasionally used for clock hands and instrument dials, enabling them to be read in the dark. Radioluminescence is also sometimes seen around high-power radiation sources, such as nuclear reactors and radioisotopes.
Luminous paint is paint that emits visible light through fluorescence, phosphorescence, or radioluminescence.
Radium and radon are important contributors to environmental radioactivity. Radon occurs naturally as a result of decay of radioactive elements in soil and it can accumulate in houses built on areas where such decay occurs. Radon is a major cause of cancer; it is estimated to contribute to ~2% of all cancer related deaths in Europe.
Radium dials are watch, clock and other instrument dials painted with luminous paint containing radium-226 to produce radioluminescence. Radium dials were produced throughout most of the 20th century before being replaced by safer tritium-based luminous material in the 1970s and finally by non-toxic, non-radioactive strontium aluminate–based photoluminescent material from the middle 1990s.
Lume is a short term for the luminous phosphorescent glowing solution applied on watch dials. There are some people who "relume" watches, or replace faded lume. Formerly, lume consisted mostly of radium; however, radium is radioactive and has been mostly replaced on new watches by less bright, but less toxic compounds. After radium was effectively outlawed in 1968, tritium became the luminescent material of choice, because, while still radioactive, it is much less potent than radium, tritium being about as radioactive as an x-ray, the decrease in radioactivity resulting from a diminishment of strength and quantity of the beta waves that are given off by tritium as an element.
The United States Radium Corporation was a company, most notorious for its operations between the years 1917 to 1926 in Orange, New Jersey, in the United States that led to stronger worker protection laws. After initial success in developing a glow-in-the-dark radioactive paint, the company was subject to several lawsuits in the late 1920s in the wake of severe illnesses and deaths of workers who had ingested radioactive material. The workers had been told that the paint was harmless. During World War I and World War II, the company produced luminous watches and gauges for the United States Army for use by soldiers.
Radium jaw, or radium necrosis, is a historic occupational disease brought on by the ingestion and subsequent absorption of radium into the bones of radium dial painters. It also affected those consuming radium-laden patent medicines.
The Radium Dial Company was one of a few now defunct United States companies, along with the United States Radium Corporation, involved in the painting of clocks, watches and other instrument dials using radioluminescent paint containing radium. The resulting dials are now collectively known as radium dials. The luminous paint used on the dials contained a mixture of zinc sulfide activated with silver, and powdered radium, a product that the Radium Dial Company named Luma. However, unlike the US Radium Corporation, Radium Dial Company was specifically set up to only paint dials, and no other radium processing took place at the premises.
Super-LumiNova is a brand name under which strontium aluminate–based non-radioactive and nontoxic photoluminescent or afterglow pigments for illuminating markings on watch dials, hands and bezels, etc. in the dark are marketed. When activated with a suitable dopant, it acts as a photoluminescent phosphor with long persistence of phosphorescence. This technology offers up to ten times higher brightness than previous zinc sulfide–based materials.
Radium-226 is the longest-lived isotope of radium, with a half-life of 1600 years. It is an intermediate product in the decay chain of uranium-238; as such, it can be found naturally in uranium-containing minerals.
Uranium tiles have been used in the ceramics industry for many centuries, as uranium oxide makes an excellent ceramic glaze, and is reasonably abundant. In addition to its medical usage, radium was used in the 1920s and 1930s for making watch, clock and aircraft dials. Because it takes approximately three metric tons of uranium to extract 1 gram of radium, prodigious quantities of uranium were mined to sustain this new industry. The uranium ore itself was considered a waste product and taking advantage of this newly abundant resource, the tile and pottery industry had a relatively inexpensive and abundant source of glazing material. Vibrant colors of orange, yellow, red, green, blue, black, mauve, etc. were produced, and some 25% of all houses and apartments constructed during that period used bathroom or kitchen tiles that had been glazed with uranium. These can now be detected by a Geiger counter that detects the beta radiation emitted by uranium's decay chain.
William John Aloysius Bailey was an American patent medicine inventor and salesman. A Harvard University dropout, Bailey falsely claimed to be a doctor of medicine and promoted the use of radioactive radium as a cure for coughs, flu, and other common ailments. Although Bailey's Radium Laboratories in East Orange, New Jersey, was continually investigated by the Federal Trade Commission, he died wealthy from his many devices and products, including an aphrodisiac called Arium, marketed as a restorative that "renewed happiness and youthful thrill into the lives of married peoples whose attractions to each other had weakened."
Despite the best efforts of the government, health, and environmental agencies, improper use of hazardous chemicals is pervasive in commercial products, and can yield devastating effects, from people developing brittle bones and severe congenital defects, to strips of wildlife laying dead by poisoned rivers.
The radium fad or radium craze of the early 20th century was an early form of radioactive quackery that resulted in widespread marketing of radium-infused products as being beneficial to health. Many radium products contained no actual radium, in part because it was prohibitively expensive, which turned out to be a grace, as high levels of radium exposure can result in radiation-induced cancer.