How Do Stink Bombs Work? Are They Safe?   Recently updated !


Stink bombs either contain one smelly chemical or else two that create a stink when mixed together.
Stink bombs either contain one smelly chemical or else two that create a stink when mixed together. (photo: Simul)

Stink bombs are products designed to release a stinky odor. Despite the name, they do not explode. Stink bombs are readily available as pranks, plus there are versions used for crowd control. Here is a look at how stink bombs work, the chemicals involved, and their safety.

How Stink Bombs Work

A stink bomb is a sealed container of either a single chemical or else two separate chemicals that are mixed to produce a smell. Typically, stinky molecules are volatile and have a small molecule weight, so they readily disperse through air.

Products containing a single chemical may be sold as 1-ml and 2-ml glass ampules. For example, ammonium sulfide stink bombs come in small, breakable containers. When crushed or thrown, the chemical is released, where it reacts with water in air to produce a stinky mixture of hydrogen sulfide (rotten egg), ammonia, and ammonium sulfide (another rotten smell).

Other products consist of two separate packets. There is a larger bag with a powdered chemical and a smaller inner bag with a liquid chemical. When the bag is crushed, the inner bag ruptures, allowing the powder and liquid to mix. This type of stink bomb usually produces hydrogen sulfide gas (rotten egg). The gas expands and ultimately pops the outer bag, releasing the unpleasant odor.

List of Chemicals Used in Stink Bombs

Ammonium sulfide and hydrogen sulfide are the most common ingredients in stink bombs, but many other smelly chemicals may be used. Most odoriferous compounds are organic, but some are inorganic:

Type of OrganicExamplesOdor
Aldehydes
ButyraldehydePungent, musty
Amines
CadaverineRotting meat
EthanolamineUnpleasant, like ammonia
PutrescineRotting meat
TriethylamineRotting fish
Carboxylic acids
Butyric acidRancid butter or vomit
Caproic acidOld cheese
Propionic acidSweat
Valeric acidStinky feet
Heterocyclics
IndoleFeces
SkatoleFeces
Inorganic sulfur compounds
Ammonium sulfideRotten eggs
Hydrogen sulfideRotten eggs
Organic sulfur compounds
ButanethiolSkunk
EthanethiolDurian or cooked cabbage
MethanethiolVomit
PropanethiolCooked cabbage
List of chemicals used in stink bombs

Are Stink Bombs Safe?

When used as directed, stink bombs are not dangerous. Most of the compounds they contain or produce have a toxicity category rating of III or IV (where I is the most toxic and IV is the least toxic). The small quantities used in a single stink bomb may cause eye or skin irritation, which should resolve within 72 hours (7 days or severe eye exposure).

However, the safety relies on the small dose of a single stink bomb and brief exposure. Stink bomb compounds are toxic at high concentrations or after prolonged exposure at low concentrations. Some chemicals, such as hydrogen sulfide, are flammable. It’s important to only use stink bombs singly and in large, well-ventilated areas. Using too many stink bombs at once can be dangerous.

How to Make a Homemade Stink Bomb

The safest and easiest stink bomb is the classic rotten egg version. Basically, you boil and egg and let it “ripen” for a few weeks. Then, you can either throw the egg or else puncture the shell with a pin and leave it to do its work. The infamous “rotten egg” smell comes from hydrogen sulfide (H2S). The human body produces small amounts of hydrogen sulfide. It’s one molecule responsible for halitosis (bad breath), plus it’s produced by bacteria, occurs in natural gas, and may be found in some well water. However, hydrogen sulfide is toxic and flammable. Throwing one rotten egg isn’t likely to cause a problem, but don’t crush a dozen. Rotting seafood is an alternative to the rotten egg. It smells horrible and doesn’t take long to achieve.

Burning human hair or pet fur smells awful. Some people wrap the hair or fur with rubber bands before igniting them. While burning rubber does increase the stink-factor, it isn’t healthy to breathe the smoke and is not recommended.

Crush pods from the stink bean plant to release a stinky, sulfurous odor.
Crush pods from the stink bean plant to release a stinky, sulfurous odor. (photo: Hariadhi)

If you have a green thumb, you can grow a plant called “stinky bean” (Parkia speciosa). Stomping on a partially dried pod from the plant releases a pungent stench. The odor is similar to that of a shiitake mushroom or boiled cabbage, but stronger and more sulfurous. The bean is edible, too, and is a popular ingredient in Indian and Indonesian cuisine.

It’s easy to make a homemade ammonium sulfide [(NH4)2S] stink bomb using a book of matches, household ammonia, and an empty 20-ounce bottle. Ammonium sulfide is one of the compounds used in store-bought stink bombs. To make the produce, cut the heads off the matches (20 matches in a book) and drop them into the empty bottle. Add a couple of tablespoons of household ammonia. Seal the bottle and allow three or four days for the match heads and ammonia react. Uncap the bottle to release the smell.

The reaction between the match heads and ammonia to produce ammonium sulfide is:

H2S + 2 NH3 → (NH4)2S

The resulting odor includes a mixture of hydrogen sulfide, ammonia, and ammonium sulfide. All of these compounds stink and all are toxic at high concentration. As with commercial stink bombs, only use homemade stink bombs in a well-ventilate area, away from heat and flames.

References

  • 40 CFR 156.64: Toxicity Category“. Code of Federal Regulations. Office of the Federal Register.
  • Ellison, D. Hank (2007). Handbook of Chemical and Biological Warfare Agents (2nd ed.). CRC Press.
  • Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  • Pain, Stephanie (July 7, 2001). “Stench Warfare“. New Scientist.
  • Trivedi, Bijal P. (January 7, 2002). U.S. Military Is Seeking Ultimate “Stink Bomb”. National Geographic News.

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