What is Uranium Glass?
Uranium glass is the older and more general term for green or yellow-colored glass that was colored with Uranium.
Vaseline glass is a term that overlaps with Uranium glass, but this refers only to the transparent yellow Uranium glass. Canary glass is an even older name for Vaseline glass (source). Depression glass is glassware made during the Great Depression, and at this time, Uranium was used in the yellow and green glassware.
Not all green or yellow glass is colored with Uranium. To test your glassware for Uranium, you can expose it to UV light (i.e. a black light). Most Uranium glass will fluoresce (glow) a bright green from the UV exposure.
Some Uranium containing glass does not fluoresce under ultraviolet light says the Museum of Radiation and Radioactivity. The yellow glass called “gemstone” does not fluoresce under UV light despite the fact that it contains Uranium, they say.
Production of Uranium Glass
Uranium has been used to color glass since the 1830s, and it is still used today for some decorative glass.
It was popular from the 1880s to the 1920s. In 1943, production of Uranium glass was stalled and it didn’t come back to previous production levels when the production did resume.
Exposure to Radioactivity from Eating and Drinking from Uranium Glass
Because the glass only contains a small amount of Uranium, many websites argue that this glass is safe to eat off of.
I asked toxicologist Dr. Lyle Burgoon about this and he explained that based on the Nuclear Regulatory Commission‘s data, “drinking from Uranium glassware would result in fairly negligible exposures to Uranium – 0.002 mrem/year. That’s about 100x less than the radiation dose per hour flying in an airplane. That’s also 5,000x less than the radiation from a single chest X-ray (EPA)”.
“If all someone did was eat off of Uranium glassware, their dose will still be about 10,000x lower than the radiation from a 1-hour airplane flight,” says Dr. Burgoon.
The U.S. Environmental Protection Agency (EPA), on the other hand, recommends against eating or drinking from Uranium glassware.
Exposure to Radioactivity from Collecting Uranium Glass
In the case where someone is handling collectible glass (not eating or drinking from it), Dr. Burgoon explains that “they will still only see at most an exposure of 0.2 mrem/year. That’s equivalent to the radiation from a 1-hour plane flight in one year”.
Exposure to Uranium from Uranium Beads/Jewelry
While researching for this article I realized that I own Uranium beads that I bought in a bead market in Ghana!
The risk of health effects of radiation from Uranium glass jewelry is generally going to be very low.
If someone were to wear a Uranium glass bead jewelry item for 8 hours every day, the total radiation exposure over that year would be the equivalent amount of radiation as a 1-hour flight in a commercial airplane, says Dr. Burgoon. That exposure over the entire year is 44x less than a single chest x-ray, he explains.
The likely dose due to wearing the jewelry is a little higher than eating off Uranium glass but both are very low.
Lead, Cadmium & Arsenic in Uranium Glass
Please keep in mind, that Uranium glass could also contain Lead, Cadmium, or Arsenic which could be significantly more of a risk than the Uranium.
A lot of vintage glassware contains Lead, as the old glass manufacturing process used Lead oxide as a component (source). Depression glass was often made with Arsenic, and some Depression glass contains lead.
The FDA started to regulate lead levels in dishware in 1971, but that doesn’t mean that newer dishware is free of Lead. (source)
Is Uranium Glass Dishwasher Safe?
In general, most vintage dishware cannot go in the dishwasher without being damaged. But there is nothing in particular about Uranium itself that would make it not safe for the dishwasher.
“While some uranium might be leached during dishwashing, it would be removed with the wash water. There is no reason to expect any uranium to remain in the dishwasher” says Ray Johnson, Certified Health Physicist.
Is Uranium Glass Microwave Safe?
Many vintage glassware items are not microwave safe; Depression glass of any color can shatter in the microwave, according to the National Depression Glass Association.
But if your Uranium glass is newer and the glass itself is microwave-safe, Dr. Burgoon is not concerned about putting Uranium glass in a microwave. He explains that the microwave should not change the dose of Uranium or the likelihood of breakage (assuming the glass is microwave-safe).
Bruce Heinmiller, Certified Health Physicist, also goes into detail on how the microwaves interact with Uranium in glass in this article.
Dr. Burgoon is a trained regulatory toxicologist, risk assessor, and biostatistician. Dr. Burgoon earned his dual Ph.D. in Pharmacology and Toxicology with Environmental Toxicology from Michigan State University.
Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.