Would you like some uranium with your tea?
From 1936-1972, the makers of Fiestaware (and also many other ceramics from that time) used uranium oxide in the glaze to get certain colors, the most common of which is a brilliant redish-orange. This however made the dining sets radioactive.
Production lines initially used uranium from natural sources, which contains a mix of uranium-238 and uranium-235, but during World War II, the US government seized uranium supplies around the country to collect the U-235 for use in atomic weapons. After the war, the ceramics were glazed with “depleted” uranium oxide, which has a smaller percentage of U-235 and therefore “depleted” of the more coveted form of uranium. Eventually, other glazes were developed and uranium oxide was no longer needed to achieve certain colors, but many sets are still available in second-hand markets around the world.
When something is “radioactive,” we are usually referring specifically to ionizing radiation, which is when high energy particles are emitted from an unstable element. Our bodies are bombarded with radiation everyday, coming from sources like cosmic rays from space or the granite in buildings. These, and many other types of exposures, are no cause for concern and are just a normal part of living on earth. Scientists called Health Physicists have studied levels of radiation exposure that are acceptable to humans (i.e. no increase in cancer risk or acute effects) and old, orange Fiestaware use falls into this category. The uranium oxide is encased in the glaze, so although your skin is exposed to the radiation, you will not ingest any, assuming the finish is not cracked.
If you’ve been dreaming of teaching your kids about radioactivity, check out Nuclear Physics for Babies for their first taste of this wild subject. 😉
Oak Ridge: https://www.orau.org/ptp/collection/consumer%20products/fiesta.htm
Landa, E. and Councell, T. Leaching of Uranium from Glass and Ceramic Foodware and Decorative Items. Health Physics 63 (3): 343-348; 1992.
Piesch, E, Burgkhardt, B, and Acton, R. Dose Rate Measurements in the Beta-Photon Radiation Field from UO2 Pellets and Glazed Ceramics Containing Uranium. Radiation Protection Dosimetry 14 (2): 109-112; 1986.