The dihydrogen monoxidehoax 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.
"Dihydrogen monoxide", shortened to "DHMO", is a name for water that is consistent with the basic rules of chemical nomenclature, but is not among the names published by IUPAC 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, revised by Craig Jackson (also a UC Santa Cruz student) in 1994, 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?".
"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). 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.
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.
The first appearance on the internet was attributed by the Pittsburgh Post-Gazette to the so-called Coalition to Ban Dihydrogen Monoxide, a hoax organization started by Craig Jackson following the initial newsgroup discussions. The site included the following warning:
in the distribution of pesticides. Even after washing, product remains contaminated by this chemical.
as an additive in certain "junk-foods" and other food products.
The water molecule has the chemical formula H2O, meaning each molecule of water is composed of two hydrogenatoms 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.
Various names for water are commonly used within the scientific community. Some such names 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.
Under the 2005 revisions of IUPAC nomenclature of inorganic chemistry, there is no single correct name for every compound. 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.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.
The use of numerical prefixes is typical nomenclature for compounds formed by covalent bonds, which are present in water. 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. Thus H2S is often simply called hydrogen sulfide, and lithium oxide is a common name for Li2O. However, the names dihydrogen sulfide, dilithium oxide, and dilithium monoxide 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. Thus for instance the IUPAC name of H2S is hydrogen sulfide rather than hydrogen monosulfide. 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
The logo of DHMO.org, primary current residence of the dihydrogen monoxide hoax
In 1989, Eric Lechner, Lars Norpchen and Matthew Kaufman circulated a Dihydrogen Monoxide contamination warning on the University of California, Santa Cruz campus via photocopied fliers. The concept originated one afternoon when Kaufman recalled a similar warning about "Hydrogen Hydroxide" that had been published in his mother's hometown paper, the Durand (Michigan) Express, and the three then worked to coin a term that "sounded more dangerous". Lechner typed up the original warning flier on Kaufman's computer, and a trip to the local photocopying center followed that night.
In 1994, Craig Jackson created a web page for the Coalition to Ban DHMO.
The Friends of Hydrogen Hydroxide was created by Dan Curtis Johnson partly as a foil on the Coalition page, to provide evidence of 'misguided' supporters of dihydrogen monoxide. This form of collaborative connivance is a classic tool of internet spoofers.
In 1997, Nathan Zohner, a 14-year-old junior high student at Eagle Rock Junior High School in Idaho Falls, Idaho, gathered 43 votes to ban the chemical, out of 50 people surveyed among his classmates. Zohner received the first prize at Greater Idaho Falls Science Fair for analysis of the results of his survey. In recognition of his experiment, journalist James K. Glassman coined the term "Zohnerism" to refer to "the use of a true fact to lead a scientifically and mathematically ignorant public to a false conclusion."
In 2001 a staffer in New Zealand Green Party MP Sue Kedgley's office responded to a request for support for a campaign to ban dihydrogen monoxide by saying she was "absolutely supportive of the campaign to ban this toxic substance". This was criticised in press releases by the National Party, one of whose MPs fell for the very same hoax six years later.
In 2002, radio talk show host Neal Boortz mentioned on the air that the Atlanta water system had been checked and found to be contaminated with dihydrogen monoxide, and set about relating the hazards associated with that "dangerous" chemical. A local TV station even covered the 'scandal'. A spokesperson for the city's water system told the reporter that there was no more dihydrogen monoxide in the system than what was allowed under the law.
The idea was used for a segment of an episode of the Penn & Teller show Penn & Teller: Bullshit!, in which actress Kris McGaha and a camera crew gathered signatures from people considering themselves "concerned environmentalists" to sign a petition to ban DHMO.
In March 2004, Aliso Viejo, California, almost considered banning the use of foam containers at city-sponsored events because dihydrogen monoxide is part of their production. A paralegal had asked the city council to put it on the agenda; he later attributed it to poor research. The law was pulled from the agenda before it could come to a vote, but not before the city received a raft of bad publicity.
In 2006, in Louisville, Kentucky, David Karem, executive director of the Waterfront Development Corporation, a public body that operates Waterfront Park, wished to deter bathers from using a large public fountain. "Counting on a lack of understanding about water's chemical makeup," he arranged for signs reading: "DANGER! – WATER CONTAINS HIGH LEVELS OF HYDROGEN – KEEP OUT" to be posted on the fountain at public expense.
Several petitions on the UK Government e-petitions Web site on this subject have been correctly identified as hoaxes and rejected.
In 2007 Jacqui Dean, New Zealand National Party MP, fell for the hoax, writing a letter to Associate Minister of Health Jim Anderton asking "Does the Expert Advisory Committee on Drugs have a view on the banning of this drug?"
On April 1, 2010, Canadian Member of Parliament Andrew Scheer used the DHMO hoax as the basis for an April Fool's Day "media release" on his web site, in which he claimed to have tabled a bill to ban the substance from all federal government buildings.
In April 2013, two presenters at Gator Country 101.9, a radio station in Lee County, Florida, told listeners dihydrogen monoxide was coming out of their water taps as part of an April Fool's Day hoax and were suspended for a few days by the station's general manager, Tony Renda. Renda later told NewsPress: "It is one thing when radio stations change their format or other crazy things they do. But you are messing with one of the big three, food, water or shelter. They just went too far; I just knew I didn't like that." The prank resulted in several calls by consumers to the local utility company, which sent out a release stating that the water was safe.