Yes, some depression glass is radioactive. Pieces that contain uranium as a coloring agent emit low levels of radiation, and this includes the popular green, yellow, and yellow-green varieties produced during the 1920s and 1930s. The uranium content typically sits around 2% by weight, though some pieces manufactured in the early 1900s contained as much as 25%.
Not all depression glass is radioactive, though. The term “depression glass” refers broadly to the colorful, inexpensive glassware mass-produced during the Great Depression. Only the pieces colored with uranium compounds qualify as radioactive. Pink, blue, amber, and clear depression glass were colored with other additives and contain no uranium at all.
Why Glassmakers Added Uranium
For hundreds of years, glassmakers used uranium compounds, specifically sodium uranate, potassium uranate, or uranium oxide, to produce striking yellow and green tones in glass. The practice dates back well before the Depression era and continued through the mid-20th century. Manufacturers weren’t trying to make anything dangerous. Uranium was simply an effective and readily available coloring agent that produced vivid hues no other additive could replicate.
The uranium in these pieces is natural uranium, containing both uranium-238 and uranium-235. Gamma spectrometry testing on a uranium glass collectible measured activity concentrations of roughly 9,031 becquerels per kilogram for uranium-238 and 472 becquerels per kilogram for uranium-235. Those numbers confirm the presence of real radioactive material, but at levels far below what would pose an acute health risk from normal handling.
Which Pieces Contain Uranium
The terminology around uranium-containing glass can get confusing because collectors use several overlapping names. Here’s how they break down:
- Vaseline glass: Transparent yellow to yellow-green glass, named for its resemblance to petroleum jelly. This always contains uranium.
- Canary glass: An older term from the 1840s that describes the same transparent yellow-green glass now called Vaseline glass.
- Custard glass: An opaque, creamy yellow glass that also contains uranium but looks quite different from the transparent varieties.
- Burmese glass: Another opaque uranium-containing glass, typically shading from yellow to pink.
The key distinction is that “uranium glass” is the broad category, while Vaseline glass, custard glass, and Burmese glass are specific styles within it. A piece of depression glass in bright green or yellow-green is a strong candidate for uranium content. A pink or cobalt blue piece almost certainly contains none.
How to Test With a Black Light
The most reliable way to confirm uranium in glass is to expose it to ultraviolet light in a dark room. If the glass glows a vivid, bright green, it contains uranium. This fluorescence is unmistakable: it’s not a faint shimmer but a strong, almost electric green glow that looks nothing like the glass’s color under normal lighting.
The fluorescence peaks when excited by UV light around 330 nanometers, which falls in the shortwave UV range. Standard black lights sold for hobby use (typically in the 365 to 395 nm range) work well enough to trigger the glow, though shorter wavelengths produce a stronger response. An inexpensive black light flashlight from a hardware store is all you need. Hold it close to the glass in a dark room, and the result will be obvious within seconds.
Glass that doesn’t fluoresce green under UV light is not uranium glass, regardless of its color in daylight. Some green depression glass was colored with iron oxide rather than uranium, and those pieces won’t glow.
Is It Safe to Collect and Display?
Uranium glass sitting on a shelf poses very little risk. The radiation it emits is primarily alpha and beta particles, which don’t travel far through air and can’t penetrate skin effectively. Keeping the glass in a display cabinet or on a shelf means your actual radiation exposure from it is negligible compared to the background radiation you absorb every day from natural sources like soil, rocks, and cosmic rays.
Handling the glass occasionally, washing it, and moving it around your home is similarly low-risk. The uranium is locked into the glass matrix, so it doesn’t rub off on your hands or become airborne under normal conditions. Millions of collectors own and handle uranium glass without any documented health consequences.
Should You Eat or Drink From It?
This is where caution is more reasonable. Acidic foods and liquids, things like orange juice, wine, vinegar, or tomato-based dishes, can leach small amounts of uranium from the glass surface over time. The concern isn’t radiation exposure so much as chemical toxicity: uranium is a heavy metal, and ingesting it in meaningful quantities can stress the kidneys.
For occasional use with non-acidic beverages like water, the leaching is minimal. But regularly eating or drinking acidic foods from uranium glass isn’t a great idea, especially for pieces with higher uranium content. Many collectors treat their uranium glass as display-only, which eliminates the question entirely. If you love the look of a uranium glass pitcher, use it as a vase rather than for lemonade.
Uranium Glass Is Still Being Made
Production of uranium glass didn’t end with the Depression. A few American companies, including Fenton Glass, Mosser, Boyd Crystal Art Glass, and Summit Glass, continued producing Vaseline glass well into the 2000s, though exclusively as decorative collectibles rather than everyday tableware. Modern pieces tend to have lower and more consistent uranium content than their antique counterparts, but they fluoresce under UV light just the same. If you buy a new piece of Vaseline glass from a specialty glassmaker, it contains real uranium and is mildly radioactive, just like the vintage originals.