Glow-In-The-Dark Necklaces

Stupid Question ™
July 16, 1998
By John Ruch
© 1998

Q: What’s in those glow-in-the-dark toy necklaces? Is it toxic?
—B.K.


A: Magic in the Nite Lite-Rope Necklaces are thin, 22-inch-long plastic sticks full of liquid that glows four to six hours when bent.

The magic liquid is Cyalume, invented 20 years ago by the American Cyanamid Company for use in emergency light sticks. Massachusetts’ Omniglow Corporation now owns the Cyalume product line. A new employee in Omniglow’s PR office tried to explain how Cyalume works, but didn’t really know. Didn’t send us a promised info packet, either.

But patent filings and an analysis of the original light stick provided by Mary Bailey in Ohio State University’s chemistry department give us the basic idea.

The American Cyanamid light stick consisted of a plastic tube containing a glass ampule. (Instead of an ampule, the Lite-Rope Necklace has a thin layer of glass down the entire stick.)

Inside the ampule are diluted hydrogen peroxide and a “phthalic ester solvent.”

Surrounding the glass ampule in the plastic tube are a “phenyl oxalate ester” and the dye.

When you bend the light stick, it breaks the glass ampule, allowing the peroxide to ooze out into the oxalate ester. The ensuing reaction creates an energized “intermediary” substance that transfers its energy to the dye molecules. The dye then gives off the excess energy as cold light, the color depending on the sort of dye.

Hydrogen peroxide and acid esters are certainly toxic at high levels and concentrations. Since they’re present here in only small amounts, Lite-Ropes are not required to carry a warning label—and don’t, except on the 50-count mailing tubes they’re shipped in.

That label says the product is non-toxic—but also says you shouldn’t cut the thing open and splash Cyalume around your eyes, skin or mouth.

The US Consumer Product Safety Commission has logged 23 complaints about chemical light sticks since 1990. None involved serious injury.

Of those, 15 involved chemical burns to the eyes. Two were stomach upsets from drinking Cyalume. One was from a supposedly exploding light stick, and the other five were from being poked in the eye or whipped with a stick.

Cyalume can also soften paint and varnish, and the dye can stain clothing. I wasn’t thrilled about the gritty glass powder I got on my fingers when I cut open a sample Lite-Rope, either.

Columbus, Ohio’s Children’s Hospital reports no light stick injuries. If you don’t want your kids to be the first, tell them not to bite into their Lite-Ropes.

But if they do get a little sick, you can always say a prayer to Omniglow’s brand new product: the Glow Cross.