Dihydrogen monoxide hoax

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Water consists of two hydrogen atoms and one oxygen atom.

The dihydrogen monoxide hoax involves calling water (H2O) by an unfamiliar name, "dihydrogen monoxide", followed by a listing of the real effects of this chemical, often presented as an argument that this substance should be regulated, labeled as hazardous, or banned. The hoax is intended to illustrate how the lack of scientific literacy and an exaggerated analysis can lead to misplaced fears.[1]

"Dihydrogen monoxide", shortened to "DHMO", is a name for water that is consistent with the basic rules of chemical nomenclature,[2] but is not among the names published by IUPAC[2] and is almost exclusively used in a satirical context.

A version of the hoax was created by Eric Lechner, Lars Norpchen and Matthew Kaufman, housemates while attending University of California, Santa Cruz in 1990,[3] revised by Craig Jackson (also a UC Santa Cruz student) in 1994,[4] and brought to widespread public attention in 1997 when Nathan Zohner, a 14-year-old student, gathered petitions to ban "DHMO" as the basis of his science project, titled "How Gullible Are We?".[5]

"Dihydrogen monoxide" may sound dangerous to those with a limited knowledge of chemistry or who hold to an ideal of a "chemical-free" life (chemophobia).[5] The only familiar common usage of the term "monoxide" is in the highly toxic gas "carbon monoxide", and the simplified term "monoxide poisoning" is commonly used to refer to poisoning by this colorless and odorless substance.[6]

The joke has been frequently extended over the years. For example, a material safety data sheet—a list of information about potentially dangerous materials used in research and industry—has been created for H2O.[7][8]

Original internet appearance[edit]

The first appearance on the internet was attributed by the Pittsburgh Post-Gazette to the so-called Coalition to Ban Dihydrogen Monoxide,[4][9] a hoax organization started by Craig Jackson following the initial newsgroup discussions. The site included the following warning:[10]

Dihydrogen monoxide:

Despite the danger, dihydrogen monoxide is often used:


The water molecule has the chemical formula H2O, meaning each molecule of water is composed of two hydrogen atoms and one oxygen atom. Literally, the term "dihydrogen monoxide" means "two hydrogen, one oxygen", consistent with its molecular formula: the prefix di- in dihydrogen means "two", the prefix mon- in monoxide means "one", and an oxide is a compound that contains one or more oxygen atoms.[11]

Various names for water are commonly used within the scientific community. Some such names[citation needed] include hydrogen oxide, as well as an alkali name of hydrogen hydroxide, and several acid names such as hydric acid, hydroxic acid, hydroxyl acid, and hydroxilic acid. The term "hydroxyl acid" used in the original hoax is a non-standard name. An additional name, μ-oxido dihydrogen, has been developed for this compound.[12]

Under the 2005 revisions of IUPAC nomenclature of inorganic chemistry, there is no single correct name for every compound.[13] The primary function of chemical nomenclature is to ensure that each name refers, unambiguously, to a single substance. It is considered less important to ensure that each substance should have a single name, although the number of acceptable names is limited.[13] Water is one acceptable name for this compound, even though it is neither a systematic nor an international name and is specific to just one phase of the compound. The other IUPAC recommendation is oxidane.[14]

The use of numerical prefixes is typical nomenclature for compounds formed by covalent bonds, which are present in water.[15][16] The prefix for the first named element is often dropped if the elements involved commonly form only one compound, or even if the number of atoms of the first-named element is the same in all the compounds of the two (or more) elements.[11] Thus H2S is often simply called hydrogen sulfide, and lithium oxide is a common name for Li2O. However, the names dihydrogen sulfide,[17] dilithium oxide,[18] and dilithium monoxide[19] are also commonly used both in industry and in universities, even though Li2O is ionic.

The "mono-" prefix is often dropped for the second-named element if it is the only common compound the elements form.[20] Thus for instance the IUPAC name of H2S is hydrogen sulfide rather than hydrogen monosulfide.[21] However, since carbon and oxygen can form several compounds (carbon monoxide, carbon dioxide, tricarbon dioxide, and dicarbon monoxide), the mono- prefix is kept, as it is with silicon monoxide and silicon dioxide. Indeed, hydrogen and oxygen do form another common compound, H2O2 (hydrogen peroxide). Using prefix nomenclature, H2O2 would be called dihydrogen dioxide. Thus, keeping the "mono-" in dihydrogen monoxide could in principle serve to distinguish it from another compound.

Public efforts involving DHMO[edit]

The logo of DHMO.org, primary current residence of the dihydrogen monoxide hoax
Danger sign in Louisville, Kentucky

See also[edit]


  1. ^ Carder, L; Willingham, P.; Bibb, D. (2001), "Case-based, problem-based learning: Information literacy for the real world", Research Strategies 18 (3): 181–190, doi:10.1016/S0734-3310(02)00087-3 .
  2. ^ a b Leigh, G. J. et al. (1998), Principles of chemical nomenclature: a guide to IUPAC recommendations, Blackwell Science Ltd, UK, pp. 27–28, ISBN 0-86542-685-6 
  3. ^ Erich Lechner (February 23, 1990), Warning! Dangerous Contamination! (original usenet posting), Usenet rec.humor.funny archive 
  4. ^ a b Kruszelnicki, Karl S. (2006), Mysterious Killer Chemical, Australian Broadcasting Corporation .
  5. ^ a b c d Dihydrogen Monoxide from Urban Legends Reference Pages, Retrieved 2006-09-25.
  6. ^ Knight, Bernard (1998), Lawyers Guide to Forensic Medicine, Routledge, p. 280, ISBN 978-1-85941-159-9 
  7. ^ "DHMO Material Safety Data Sheet". Improbable Research. 
  8. ^ "Material Safety Sheet - DIHYDROGEN MONOXIDE". DHMO.org. 
  9. ^ Roddy., Dennis B. (1997), Internet-inspired prank lands 4 teens in hot water, Pittsburgh Post-Gazette (published April 19, 1997) 
  10. ^ a b Craig Jackson (1994), Ban Dihydrogen Monoxide!, Coalition to ban DHMO, archived from the original on 1996-10-31 . Coalition to ban DHMO officers, Coalition to ban DHMO, archived from the original on 1997-01-25 .
  11. ^ a b Van Bramer, S.E. (1996), Chemical Nomenclature .
  12. ^ "/www.bluelaketec.com". Bluelake Technologies. Retrieved 2010-04-02. 
  13. ^ a b IUPAC Report: General Aims, Functions and Methods of Chemical Nomenclature (March 2004) http://www.iupac.org/reports/provisional/abstract04/RB-prs310804/Chap1-3.04.pdf
  14. ^ Leigh, G. J. et al. 1998. Principles of chemical nomenclature: a guide to IUPAC recommendations, p. 99. Blackwell Science Ltd, UK. ISBN 0-86542-685-6
  15. ^ Leigh, G. J. et al. 1998. Principles of chemical nomenclature: a guide to IUPAC recommendations, p. 28. Blackwell Science Ltd, UK. ISBN 0-86542-685-6.
  16. ^ Nishiura, James, "Polar Covalent Bonds", Biology 4, City University of New York .
  17. ^ Office of Environmental Health Hazard Assessment, Dihydrogen sulfide (PDF), California Environmental Protection Agency .
  18. ^ Diagnostics on calculations: Species with negative natural orbital occupation numbers, National Institutes of Health 
  19. ^ Lithium oxide, PubChem public chemical database 
  20. ^ Leigh, G. J. et al. 1998. Principles of chemical nomenclature: a guide to IUPAC recommendations, p. 28. Blackwell Science Ltd, UK. ISBN 0-86542-685-6: "The multiplicative prefixes may not be necessary if the oxidation states are explicit or are clearly understood."
  21. ^ Hydrogen sulfide, PubChem public chemical database .
  22. ^ The original poster circulated at UC Santa Cruz (PDF)
  23. ^ http://www.armory.com/~crisper/DHMO/
  24. ^ Glassman, James K (1997). "Dihydrogen Monoxide: Unrecognized Killer". The Washington Post. 
  25. ^ Campaign launched against dihydrogen monoxide, Deutsche Presse-Agentur, April 1, 1998 .
  26. ^ a b Gnad, Megan (2007-09-14). "MP tries to ban water". New Zealand Herald. 
  27. ^ http://fellowshipofminds.wordpress.com/2012/06/05/neal-boortz-to-hang-up-the-headphones/
  28. ^ "Penn & Teller: Bullshit!" Environmental Hysteria (2003), Internet Movie Database 
  29. ^ Local officials nearly fall for H2O hoax, at MSNBC March 15, 2004, Retrieved 2006-09-25.
  30. ^ Water without hydrogen would warrant warning, Louisville Courier-Journal, Monday, July 17, 2006 (link inactive as of Friday, May 18, 2007)
  31. ^ Danger! H in H2O, Chemical & Engineering News, October 23, 2006 webcite mirror
  32. ^ Petition to "Ban dihydrogen monoxide" on UK Government e-petitions Web site
  33. ^ "Questions And Answers – Wednesday, September 12, 2007". Scoop. September 13, 2007. 
  34. ^ "PDF file of related correspondence" (PDF). Scoop. September 13, 2007. 
  36. ^ Sosiaalinen VaalikonePitäisikö lakia tiukentaa vetyhapon saatavuuden ja käytön osalta?, Sosiaalinen Vaalikone, February 25, 2011 .
  37. ^ "Florida DJs Are Off the Hook for Their Successful April Fool's Prank". The Atlantic Wire. April 3, 2013. Retrieved 2013-04-11. 
  38. ^ "Presenters suspended for April Fool hoax". Radio Today. April 1, 2013. Retrieved 2013-04-02. 
  39. ^ "2 radio personalities suspended due to April Fools' Day prank". WFTV. April 2, 2013. Retrieved 2013-04-02. 

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