Poison Centers Get 13 Times the Glow-Stick Calls on Halloween. The Snap Breaks a Vial of Hydrogen Peroxide

Every year the busiest night for glow sticks is also the busiest night for glow-stick phone calls. America’s Poison Centers, the body that accredits and represents the country’s poison centers, told ABC News last Halloween that on a typical day poison centers receive around 20 calls for glow products. On Halloween, around 260. Nobody is calling because the stick is haunted. They are calling because a tube of oxidizer chemistry ended up in a mouth or an eye, which is where it is least welcome.

This article explains that chemistry: what is in the tube, what the snap actually breaks, why the colour comes from a dye and not the reaction, why a glow stick in the freezer seems to pause, and where the whole thing came from. It is not medical guidance. For any exposure, the authority is Poison Control (1-800-222-1222 in the U.S.), and the first-aid lines below are quoted from it, not written by us. Alliance Chemical sells hydrogen peroxide and oxalic acid; we do not make or sell glow sticks.

What is inside a glow stick?

Two compartments and four kinds of ingredient. C&EN’s explainer describes the layout: “The glow stick’s outer plastic tube holds a solution of an oxalate ester and an electron-rich dye along with a glass vial filled with a hydrogen peroxide solution.” The National Capital Poison Center, which runs Poison Control, names the parts the same way: “The hydrogen peroxide is contained in a glass vial, which separates it from diphenyl oxalate or phthalate, a dye and sodium salicylate, in the plastic tube.”

The last row is the one most consumer pages get slightly wrong, and Poison Control’s own sentence shows why. It lists the reactive chemicals as hydrogen peroxide “and either diphenyl oxalate (i.e., cyalume) or a phthalate”. In the chemistry, the phthalate is not an alternative reactant. It is the solvent. The Royal Society of Chemistry’s teaching column on the reaction makes the point in passing when it explains why schools rarely run the commercial recipe: it relies on “solvents that are either unlikely to be found in a typical school store (diethyl phthalate), or are unsuitable for use in school (dichloromethane).” The oxalate ester does the reacting; the phthalate keeps it in solution. Both are in the tube, which is why both end up on the list.

How does snapping a glow stick make light?

The snap is a mixing step, not an ignition. C&EN’s explainer puts it in one sentence: “The signature snap that starts the reaction signals that you’ve broken the glass tube, releasing the hydrogen peroxide.” Shaking the stick spreads the peroxide through the ester solution, and the chemistry runs in a short chain that the Royal Society of Chemistry summarises like this: “The initial oxidation product is 1,2-dioxetanedione, which rapidly decomposes to electronically excited carbon dioxide.”

1. Peroxide meets ester. Hydrogen peroxide attacks the oxalate ester. In the textbook version with diphenyl oxalate, the two phenol groups are pushed off.
2. A strained ring forms. What is left of the oxalate closes into 1,2-dioxetanedione, a four-membered ring of two carbons and two oxygens with two more oxygens attached. It is a very small, very strained molecule holding a lot of chemical energy.
3. The ring breaks into carbon dioxide. It falls apart almost at once into two molecules of CO₂, and the energy released goes into an excited state rather than into heat.
4. The dye takes the energy. On its own, the excited intermediate is a poor light source. In the RSC’s words, “Alone this will not efficiently chemiluminesce but a fluorescent dye can capture energy from the CO₂ efficiently and release this in the form of visible light.”
5. The dye relaxes and emits a photon. The dye is not used up in this step. It returns to its ground state and is ready to accept energy again, which is why a small amount of dye can colour the whole stick for hours.

This family of reactions is called peroxyoxalate chemiluminescence: light from a chemical reaction, as opposed to light from heat (a candle) or from absorbed light (a glow-in-the-dark sticker, which has to be charged by a lamp first). That is why a glow stick feels cool in the hand. The energy that leaves the tube leaves mostly as light.

Why does the dye, not the reaction, set the colour?

Because every glow stick runs the same reaction and only the dye changes. The excited intermediate hands the same packet of energy to whatever fluorescent molecule is nearby, and that molecule emits at its own characteristic wavelength. Swap the dye and you swap the colour without touching the peroxide or the ester. The RSC’s teaching column lists the dyes it has used for its demonstration:

The chlorophyll line is the best one in the table. A leaf is green because chlorophyll absorbs red and blue light and reflects green. Give the same molecule energy from a chemical reaction instead and it emits in the red, at its own fluorescence wavelength. The colour you see on a leaf and the colour it glows are different questions, and a glow stick answers the second one.

Does putting a glow stick in the freezer make it last longer?

It slows it down, which is not quite the same thing. Like most reactions, the peroxide-ester reaction runs faster when warm and slower when cold. The RSC column demonstrates it with a sealed vial: “Temperature effects on the rate of reaction can be easily demonstrated by dipping the lidded sample vial in an ice bath and back into warm water – the glow will diminish and return accordingly.”

A stick has a fixed amount of fuel. The total amount of light it can produce is set by how much ester and peroxide are in it, not by the temperature. Warming spends that budget faster, so the stick is brighter for a shorter time. Cooling spends it slower, so the stick is dimmer, and it seems to pause in a freezer. When it warms up, it picks up where it left off. The freezer does not add light; it only changes the rate at which the stick uses what it has.

Why do poison centers get 13 times the calls on Halloween?

Because glow sticks spend one night a year in the hands, and mouths, of very small children in costume. The figures come from America’s Poison Centers, as reported by ABC News on 1 November 2025: “On a typical day, poison centers around the country will receive around 20 calls total for glow products. On Halloween, that number jumps to around 260, according to America’s Poison Centers.” On our arithmetic, that is about 13 times the normal daily volume, concentrated into one evening.

The calls are mostly about irritation, not poisoning. Poison Control’s page on glow sticks says plainly: “Glow sticks are not poisonous.” It also says the liquid is unpleasant: “The liquid in the glow stick can be irritating and cause a burning sensation to the eyes and skin.” The ingredients explain both halves. An oily organic solvent carrying an oxidizer and a base is exactly the kind of liquid that stings an eye and tastes awful, without being a poison in the sense of a toxic dose.

The first-aid instructions are Poison Control’s, and they are short. For eyes: “If it gets in someone’s eye, immediately rinse the eye with running water for 15 minutes.” For skin: “If it gets on the skin, wash with soap and water.” And the line America’s Poison Centers puts in its Halloween guidance, which is the whole prevention plan in six words: “Glow sticks should be worn, not chewed.” For anything beyond that, call 1-800-222-1222 or use the online Poison Control tool.

Who invented the glow stick?

One chemist found the light, and a chemical company made it last. In 1963 Edwin Chandross published “A new chemiluminescent system” in Tetrahedron Letters, reporting visible light from the reaction of oxalyl chloride, hydrogen peroxide and a fluorescent compound. Oxalyl chloride is a corrosive, water-reactive liquid: a fine reagent, and a poor thing to seal inside a toy.

The practical version came from Michael Rauhut and colleagues at American Cyanamid, who worked through the late 1960s on replacing oxalyl chloride with oxalate esters stable enough to store and bright enough to use. Rauhut’s group published the chemistry in the Journal of the American Chemical Society in 1966 and reviewed it in Accounts of Chemical Research in 1969. The patent record shows the result: U.S. Patent 3,749,679, “Carboalkoxy substituted bis-phenyl oxalates as superior chemiluminescent materials”, names Rauhut as inventor and was granted to American Cyanamid on 31 July 1973. Those substituted phenyl oxalates are the long-lived esters behind the commercial light stick.

What this means on a specification

Most people who search for glow-stick chemistry want to understand the toy. A smaller group, mostly teachers and lab technicians, want to run the reaction as a demonstration. The RSC column is the reference for that, and it is a fume-cupboard procedure with its own hazards list, not a kitchen activity. Its kit uses “2 cm³ 10 vol hydrogen peroxide in ethanol”. On our arithmetic, 10-volume peroxide is roughly a 3% solution, the same strength as the familiar brown bottle.

The oxalate row is worth reading twice. The “oxalate” in an oxalate ester is the same two-carbon backbone as oxalic acid, and the esters are derived from it. But oxalic acid is not a glow-stick ingredient. The reaction needs the ester, because its phenol groups are the parts that leave as the strained ring forms in step one above. The RSC kit uses one specific ester, bis(2,4,6-trichlorophenyl) oxalate, known as TCPO.

About supply. This article explains general glow-stick chemistry and reports figures and guidance published by poison centers and chemistry educators. It makes no claim about ours: we do not make or sell glow sticks, and nothing here says that the hydrogen peroxide or oxalic acid we list is used in any glow product. Grades, pack sizes and prices are on the product pages.

Common questions

What chemicals are in a glow stick?

Hydrogen peroxide in a sealed glass vial, and around it, in the plastic tube, an oxalate ester such as diphenyl oxalate, a fluorescent dye, a base catalyst such as sodium salicylate and an organic solvent, often a phthalate ester. Bending the stick breaks the vial so the peroxide can reach the ester.

Why do glow sticks glow?

Hydrogen peroxide oxidizes the oxalate ester to 1,2-dioxetanedione, a strained, energy-rich intermediate that breaks down into carbon dioxide. The energy passes to a fluorescent dye, which emits it as visible light. This is called peroxyoxalate chemiluminescence.

Is the liquid in a glow stick poisonous?

Poison Control says glow sticks are not poisonous, but the liquid can irritate the mouth, skin and eyes. For eyes it advises rinsing with running water for 15 minutes, and for skin washing with soap and water. For any exposure, call Poison Control at 1-800-222-1222.

Does putting a glow stick in the freezer make it last longer?

Cold slows the reaction, so the stick dims and lasts longer, and it brightens again when it warms. It does not add light: the total output is set by the amount of peroxide and ester in the stick, and temperature only changes how fast it is spent.

What decides the colour of a glow stick?

The dye. Every stick runs the same peroxide-and-ester reaction, and the dye that catches the energy emits at its own wavelength. Rubrene gives orange, 9,10-diphenylanthracene gives blue and rhodamine B gives red.

How many glow-stick calls do poison centers get on Halloween?

Around 260, against around 20 on a typical day, according to America’s Poison Centers as reported by ABC News in November 2025. That is about 13 times the normal daily volume, on our arithmetic.

What we stock

Hydrogen Peroxide 3% Technical Grade

About 10-volume strength, for general use, quart to tote.

Hydrogen Peroxide 30% ACS Grade

Reagent-grade stock for labs that dilute to the method.

Oxalic Acid ACS Grade

The parent acid of the oxalate family, for reagent work and wood bleaching.

Key numbers and sources