Undark
Encyclopedia
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 watch dials. 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.
and
Luminous paint
Luminous paint or luminescent paint is paint that exhibits luminescence. In other words, it gives off visible light through fluorescence, phosphorescence, or radioluminescence.-Fluorescent paint:...
made with a mixture of radioactive radium
Radium
Radium is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, becoming black in color. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226,...
and zinc sulfide
Zinc sulfide
Zinc sulfide is a inorganic compound with the formula ZnS. ZnS is the main form of zinc in nature, where it mainly occurs as the mineral sphalerite...
, as produced by the U.S. Radium Corporation
United States Radium Corporation
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...
between 1917 and 1938. It was used primarily in watch dials. The people working in the industry who applied the radioactive paint became known as the Radium Girls
Radium Girls
The Radium Girls were female factory workers who contracted radiation poisoning from painting watch dials with glow-in-the-dark paint at the United States Radium factory in Orange, New Jersey around 1917....
, 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
Radium jaw
Radium jaw is an occupational disease brought on by the ingestion and subsequent absorption of radium into the bones of radium dial painters. The symptoms are necrosis of the mandible and the maxilla as well as constant bleeding of the gums and after some time, severe distortion due to bone...
in the dial painters.
Undark was also available as a kit for general consumer use and marketed as glow-in-the-dark paint.
Similar products
Mixtures similar to Undark, consisting of radium and zinc sulphide were used by other companies. Trade names include:- Luna used by the Radium Dial CompanyRadium Dial CompanyThe now defunct Radium Dial Company, was one of a few 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. These dials are collectively known as radium dials...
, a division of Standard Chemical Company
and
- Marvelite used by Cold Light Manufacturing Company (a subsidiary of the Radium Company of Colorado)
Further reading
- Clark, Claudia. (1987). Radium Girls: Women and Industrial Health Reform, 1910-1935. University of North Carolina Press. ISBN 0-8078-4640-6.
- Ross Mullner. (1999) Deadly Glow. The Radium Dial Worker Tragedy. American Public Health Association. ISBN 0-8755-3245-4.
- National Council on Radiation Protection and Measurements. "Radiation Exposure from Consumer Products and Miscellaneous Sources. NCRP Report No. 56. 1977.
- Scientific American (Macklis RM, The great radium scandal. Sci.Am. 1993 Aug: 269(2):94-99)