It’s true some Fiestaware is radioactive. Red pottery from the early to mid 20th century is particularly likely to emit significant radiation. However, not all colors of old Fiestaware are radioactive and modern Fiesta dinnerware is perfectly safe. Here’s a look at why Fiesta is radioactive, whether it’s safe to use, and how to tell whether your Fiestaware is radioactive.
Why Fiestaware Is Radioactive
Fiesta dinnerware that’s radioactive contains uranium oxide in its ceramic glaze. For a while, uranium oxide was commonly used in glazes because of the vivid color it imparted. Red and ivory-colored dishes manufactured in certain years contain the most uranium oxide and are the most radioactive, but other glaze colors also contain the compound. The uranium emits alpha particles and neutrons. When bound to the cookware, the alpha particles can’t even penetrate a sheet of paper, much less food. However, acidic foods (like spaghetti sauce) or a crack allow chemicals in the glaze to leach into food. Eating food that has absorbed compounds from the pottery or glaze is much more dangerous because alpha particles can penetrate the esophagus and digestive tract. Also, leaching is unhealthy because uranium, lead, and other heavy metals used in old pottery are toxic.
The half-life of uranium-238 is 4.5 billion years, so Fiestaware is as radioactive today as when it was made. The uranium decays into thorium-234, which emits beta and gamma radiation. Thorium-234 has a half-life of 24.1 days and decays into protactinium-234 (a beta and gamma emitter) and uranium-234 (an alpha and gamma emitter).
How Radioactive Is Fiestaware? Is It Safe?
There is no record of anyone ever becoming sick from manufacturing or using radioactive Fiestaware. Even so, the U.S. Environmental Protection Agency advises consumers to avoid using any radioactive glazed ceramics for food or drink use or storage.
Researchers at Oak Ridge National Laboratory tested a 7-inch red Fiesta plate and determined it released enough radiation to expose anyone in the same room to gamma radiation, anyone touching the plate to beta radiation, and anyone eating acidic food from the plate to alpha radiation. The radioactivity was about 3 to 10 milli-Roentgen per hour (mR/hr). A single red plate contains about 4.5 grams of uranium or is about 20% uranium, by weight. The scientists estimate that eating off radioactive dinnerware daily would lead to ingesting about 0.21 grams of uranium per year. Similarly, using a radioactive red ceramic teacup daily would result in an annual radiation does of 400 mrem to the lips, 1200 mrem to the fingers, and some ingestion of uranium from leaching. Ingesting uranium increases the risk of tumors and cancer, especially of the gastrointestinal tract.
In summary, if you have radioactive Fiestaware, it’s not a good idea to eat off of it. If you do, reserve it for special occasions and only use undamaged pieces. Even displaying Fiestaware carries some risk, but it’s not significant unless you have a lot of pieces or spend a lot of time in close proximity to the dishes.
How to Tell If Fiestaware Is Radioactive
The only sure way to know if your Fiesta dinnerware is radioactive is to test it with a Geiger counter. Assuming you don’t have a Geiger counter, you can tell which Fiestaware is radioactive based on the year it was made. Fiestaware made between 1936 and 1972 may be radioactive.
Fiesta first started selling colored dinnerware in 1936. Most Fiestaware (and colored ceramics made by other companies) contained uranium oxide from 1936 until 1943. In 1943, uranium was needed for weapons for World War II, so manufacturers stopped using it in ceramics. Homer Laughlin, the company that makes Fiesta, resumed using uranium in its red glaze in the 1950s. However, this was depleted uranium, which was less radioactive than the original material. The use of depleted uranium in Fiestaware ended in 1972.
Fiesta dishes made after 1972 do not contain uranium and are not radioactive. Modern Fiesta is different in other ways, too. In 1986, the company changed from a semi-vitreous clay to a fully vitrified clay. The new claw required new glazes. Modern Fiestaware is hard, smooth, glossy, and can be used in the microwave, oven, and dishwasher. It’s also lead-free.
It’s Not Just Fiesta
While many people know Fiestaware can be radioactive, they may not realize other companies used similar uranium-containing glazes. Fiesta’s ceramics actually aren’t as radioactive as many other items produced during the same timeframe. Red and orange glazed ceramics are among the products mostly likely to be radioactive. Vaseline glass is also radioactive, although it’s usually green, yellow, or blue.
Whether cookware is radioactive or not, don’t use it for food if it has cracks or chips. Even compounds that aren’t radioactive can pose a health risk if they leach into food.
References
- Buckley et al. (1980). Environmental Assessment of Consumer Products Containing Radioactive Material. Nuclear Regulatory Commission. NUREG/CR-1775.
- Landa, E; Councell, T. (1992) “Leaching of Uranium from Glass and Ceramic Foodware and Decorative Items”. Health Physics 63 (3): 343-348.
- National Council on Radiation Protection and Measurement (1987). Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources. NCRP Report N0. 95.
- Nuclear Regulatory Commission (June 2001). Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials. NUREG 1717.
- Oak Ridge Associated Universities (1999). Fiesta Ware (ca. the 1930s).
- Piesch, E.; Burgkhardt, B.; Acton, R. (1986) “Dose Rate Measurements in the Beta-Photon Radiation Field from UO2 Pellets and Glazed Ceramics Containing Uranium”. Radiation Protection Dosimetry 14 (2): 109-112.
- Vaughn Aubuchon (2006). Geiger Counter Comparison – Popular Models.