"RADIOACTIVE RED" FIESTAWARE PLATES

Made with Natural Uranium Glaze, 1936-1943

General

The radiation level of the red/orange plates, measured by a geiger "pancake probe," averages about 25,000. cpm. This is in the middle level of radiation shown by uranium rocks found in the field. The radiation level of white/ivory Fiesta plates, based on 2% uranium in the glaze, is only about 1,000 cpm, using a pancake probe.  The white/ivory plates are barely measurable at all with a "yellow toy geiger, CDV-700.

The following is a Googled report on these famous vintage plates; the report lacks the photos.  Sorry about the missing photos, but my photos can substitute.  The 

The Fiesta dinnerware line was introduced in 1936 with a choice of five colors: red, blue, green, yellow and ivory. Red was the first color that the company selected when designing the product, and blue was the second (these were the colors of the Fiesta ware that Andy Warhol collected). Since the idea was to mix and match the dinnerware, the five colors had to be compatible.

Fiesta red has always been the most popular color even though it was the most expensive. The higher price was due to the cost of the raw materials and the fact that the production of the red required a greater level of control during the firing process.

The red color was achieved by adding uranium oxide in the glaze  -  measurements have indicated that by weight, up to 14 % of the glaze might be uranium.  How much glaze was employed per plate is unclear but it has been estimated that a single plate contains 4.5 grams of uranium (Buckley et al). Piesch et al estimated the glaze thickness at 0.2 mm.  

Since this uranium could be used in the production of an atomic bomb, Fiesta red became a victim of World War II when the US government confiscated the company’s stocks of uranium. Fiesta red disappeared until 1959 when production resumed, this time using depleted uranium (DU) rather than the original natural uranium.  The Fiesta red plate in the above photo was made from depleted uranium while the ivory plate was made from natural uranium.

In 1969 the entire Fiesta ware line was discontinued, and in its place the company produced what was known as Fiesta Ironstone. The latter, which was only manufactured in Fiesta red (aka Mango Red), didn’t last long. It was discontinued in 1973.  This was the end of Fiesta red.  Years later, in 1986, a new line of Fiesta ware was introduced but without the red color.

                        1936 – 1943  Fiesta red was produced using natural uranium

                        1959 – 1969 Fiesta red Fiesta Ware was produced using depleted uranium

                        1969 - 1973 Fiesta red Fiesta Ironstone was produced using depleted uranium

It is worth noting that the use of uranium to produce a red ceramic glaze was not limited to Fiesta ware.  Almost any antique ceramic with a deep orange/red color is likely to be radioactive, e.g., that produced by the Bauer Pottery Company.  In addition, various manufacturers, including the Homer Laughlin Company, have used uranium to give their ceramics other colors, e.g., yellow, green, brown.  Buckley et al estimated that 2 million pieces of dinnerware between 1959 and 1969 that employed uranium containing glaze.

                                 Estimates of Radiation Exposures

A very detailed analysis of the radiation exposures due to uranium in dinnerware can be found in the Nuclear Regulatory Commission publication “Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials” (NUREG 1717).

There are three principal radiation exposure pathways associated with Fiesta Ware and other uranium containing tableware:

1.    Exposure to the body from the gamma rays emitted by radionuclides in the ceramic glaze

Buckley et al reported exposure rates of 0.5 and 15 mR/hr at the surface of a dinner plate and 0.002 and 0.3 mR/hr at one meter.

The following effective dose equivalent rates were reported in NUREG-1717 for the gamma rays emitted by uranium-containing dinnerware (20 % by weight uranium):

Distance                             10” Plate                                  3.5” Cup

             1 foot                           6.5 x 10^-4 mrem/hr                    3.7 x 10^-4 mrem/hr

            3 feet                            7.7 x 10^-5 mrem/hr                    4.1 x 10^-5  mrem/hr

            6 feet                            1.9 x 10^-5 mrem/hr                    1.1 x 10^-5 mrem/hr