In 1997, a 14-year-old boy at Eagle Rock Junior High School in Idaho Falls began telling his classmates about the dangers of dihydrogen monoxide.
"Dihydrogen monoxide is colorless, odorless, tasteless, and kills uncounted thousands of people every year. Most of these deaths are caused by accidental inhalation of DHMO, but the dangers of dihydrogen monoxide do not end there," information given out to fellow students read, per Snopes. "Prolonged exposure to its solid form causes severe tissue damage. Symptoms of DHMO ingestion can include excessive sweating and urination, and possibly a bloated feeling, nausea, vomiting and body electrolyte imbalance. For those who have become dependent, DHMO withdrawal means certain death."
The info sheet compiled by Nathan Zohner went on to explain that DHMO is a major component of acid rain, can cause severe burns, and has been found in tumors taken from cancer patients. The sheet continued to hype up the dangers of this compound.
"Quantities of dihydrogen monoxide have been found in almost every stream, lake, and reservoir in America today. But the pollution is global, and the contaminant has even been found in Antarctic ice. DHMO has caused millions of dollars of property damage in the midwest, and recently California."
Despite this, Zohner explained, the substance was still in wide use, being used as everything from an additive in junk food, to a fire retardant.
"The American government has refused to ban the production, distribution, or use of this damaging chemical due to its 'importance to the economic health of this nation.' In fact, the navy and other military organizations are conducting experiments with DHMO, and designing multi-billion dollar devices to control and utilize it during warfare situations," Zohner's info sheet concluded. "Hundreds of military research facilities receive tons of it through a highly sophisticated underground distribution network. Many store large quantities for later use."
After getting the info out there, Zohner then asked 50 classmates whether the substance should be banned. Forty-three out of the 50 – or 86 percent of the class – "voted to ban dihydrogen monoxide because it has caused too many deaths".
This was of course concerning to Zohner, because dihydrogen monoxide is water. By giving it an unfamiliar name and simply listing facts about, Zohner was able to convince the majority of his class that water should be banned, even though dihydrogen monoxide (two hydrogen, one oxygen) merely describes the more familiar H2O. Though we don't have the data to go on, it's likely that the term "monoxide" was associated by some with carbon monoxide and its sometimes deadly effects.
The schoolchildren were not the only ones to be taken in by the hoax, which spreads around from time to time. In 2007, New Zealand MP Jacqui Dean signed a letter calling for water to be banned. In 2011, two radio DJs in Lee County, Southwest Florida, were temporarily suspended after warning listeners that dihydrogen monoxide was coming out of the taps. Residents began calling the utility company, believing the water to be unsafe, simply because it contained water.