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Practices of Science: Interpreting Safety Information

NGSS Science and Engineering Practices

Read the following safety information and answer the questions.


Dihydrogen Monoxide:  Safety Information


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<p><strong>SF Fig. 1.1 </strong>Dihydrogen monoxide (DHMO) chemical safety label</p>

SF Fig. 1.1 Dihydrogen monoxide (DHMO) chemical safety label

Image by Alyssa Gundersen

Dihydrogen monoxide (DHMO, SF Fig. 1.1) is a chemical compound that is commonly used in lab investigations. This chemical compound, sometimes referred to as hydric acid, is colorless and odorless. DHMO is known to be a part of many environmental hazards, toxic substances, diseases, and disease-causing agents. Each year DHMO is listed as a contributing factor in thousands of deaths, and it contributes to millions of dollars of damage to personal property and the environment. However, DHMO continues to be used widely by industry, government, and consumers worldwide. See Table SF Table 1.1 for a summary of the uses, effects, and hazards of DHMO.


SF Table 1.1. Some uses, effects, and hazards of DHMO.
Dihydrogen monoxide is used
  • as an industrial solvent and coolant,
  • in nuclear power plants,
  • by elite athletes to improve performance,
  • in biological and chemical weapons manufacture,
  • as a spray-on fire suppressant and retardant,
  • as a hydrocarbon combustion byproduct in furnaces and air conditioning compressors,
  • in pesticide production and distribution,
  • as an additive to food products,
  • in cough medicines and other liquid pharmaceuticals,
  • in shampoos, shaving creams, deodorants and numerous other bathroom products,
  • as a preservative in fresh produce, and
  • in the coffee available at major coffee houses.
Dihydrogen monoxide
  • is a major component of acid rain,
  • contributes to soil erosion,
  • leads to corrosion and oxidation of many metals,
  • causes short-circuiting of electrical systems, and
  • decreases effectiveness of automobile brakes.

Some hazards of dihydrogen monoxide are

  • death due to accidental inhalation of liquid DHMO, even in small quantities,
  • severe tissue damage caused by prolonged exposure to solid DHMO,
  • severe burns from exposure to gaseous DHMO, and
  • pre-cancerous tumors and lesions composed largely of liquid DHMO.
Symptoms of accidental dihydrogen monoxide overdose include 
  • excessive sweating or urination,
  • a bloated feeling, nausea, or vomiting,
  • electrolyte imbalance, and
  • hyponatremia (dangerously low sodium levels, which can lead to heart, liver, and kidney failure).

Table adapted from


Question Set
  1. Based on the safety information, how do you think DHMO should be regulated and handled?
  2. What is the meaning of the prefix di-? What is the meaning of the prefix mon(o)-?
  3. Based on your answer to Question 2, what is DHMO? Consult with your classmates and teachers if necessary.
  4. Now that you know what DHMO is, explain some of the statements in the safety information:
    1. Accidental inhalation of DHMO, even in small quantities, can cause death.
    2. Prolonged exposure to solid DHMO causes severe tissue damage.
    3. DHMO is found in biopsies of pre-cancerous tumors and lesions.
    4. DHMO is a major component of acid rain.
    5. DHMO contributes to soil erosion.
    6. Elite athletes use DHMO to improve performance.
    7. DHMO is used in cough medicines and other liquid pharmaceuticals.
    8. Symptoms of accidental DHMO overdose include excessive sweating or urination.
  5. Why do you think it is important to understand chemical names, even for common substances?
  6. What do you think was the author’s intended purpose in describing DHMO in this way?
  7. A Materials Safety Data Sheet (MSDS) is a way to convey safety information about a chemical. Do an internet search for the MSDS of DHMO (search using its common name). How does this information differ from the information presented in the reading?
  8. What do each of the numbers and the term “oxy” mean on DHMO’s safety label (SF Fig. 1.1)?
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.