Mercury Thermometers

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In a mercury thermometer, a glass tube is filled with mercury and a standard temperature scale is marked on the tube. With changes in temperature, the mercury expands and contracts, and the temperature can be read from the scale.  Mercury thermometers can be used to determine body, liquid, and vapor temperature. Mercury thermometers are used in households, laboratory experiments, and industrial applications. 

Household Uses of Mercury Thermometers

Common household uses of mercury thermometers include fever thermometers and oven, candy and meat thermometers.

Fever Thermometers

Mercury fever thermometers are made of glass the size of a straw, with a silvery-white liquid inside. They are common in many households, schools and medical facilities. There are two general types of mercury thermometers that measure body temperature:

  • oral/rectal/baby thermometers, containing about 0.61 grams of mercury
  • basal temperature thermometers (used to track slight changes in body temperature), containing about 2.25 grams of mercury

Is There Mercury in My Thermometer?

  • If there is no liquid in your thermometer, for example, if it uses a metallic strip or coil to measure temperature (like most meat thermometers do), it is not a mercury thermometer.
  • If the liquid in the thermometer bulb is any color other than silver, it is not a mercury thermometer.
  • If the liquid in your thermometer bulb is silver, then the liquid might be
    • mercury, or 
    • a non-toxic compound that looks similar to mercury.   

Learn more about how to tell if there is mercury in your fever thermometer.

Educational and Medical Uses of Mercury Thermometers

Mercury thermometers may be used in many applications, including chemical experiments, water and acid baths, blood banks, ovens and incubators

Industrial Uses of Mercury Thermometers

Mercury thermometers are used in:

  • power plants and piping
  • chemical tanks and vats
  • heating and cooling equipment
  • breweries, canneries
  • bakeries, candy making
  • dairies, ships
  • wineries and distilleries
  • paint kettles

Phasing out Mercury Thermometers in Industrial and Laboratory Settings

EPA has launched an effort to reduce the use of mercury-filled non-fever thermometers used in industrial settings where suitable alternatives exist. As part of a partnership EPA developed with the National Institute of Standards and Technology (NIST), NIST no longer provides calibration services for mercury thermometers. You can read more about the impact the decision will have in NIST’s February 2011 press release announcing the change.

In January 2012, EPA issued a final rule incorporating updated ASTM International (ASTM) standards into EPA regulations (PDF)(11 pp, 204 K, About PDF).Exit These changes provide flexibility to use alternatives to mercury-containing thermometers. The rule applies to certain regulations pertaining to:

  • petroleum refining,
  • power generation, and
  • polychlorinated biphenyl (PCB) waste disposal.

To date, multiple ASTM standards have been updated to approve the use of mercury-free alternatives for temperature measurement. View a list of the updated ASTM standards.

For more information about phasing out industrial mercury thermometers, visit EPA's Phasing Out of Mercury Thermometers Used in Industrial and Laboratory Settings page.

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Restrictions on Sales of Mercury Fever Thermometers

Some states and municipalities have passed laws or ordinances barring the manufacture, sale and/or distribution of mercury fever thermometers. This is to help remove the threat of thermometer breakage and the subsequent release of mercury vapor indoors. At least 13 states -- California, Connecticut, Illinois, Indiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, Rhode Island, Oregon, and Washington -- have passed such laws. The Health Care Without Harm website presents information on specific state laws, resolutions and declarations.Exit

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Alternatives to Mercury Fever Thermometers

A variety of accurate and reliable mercury-free fever thermometers are available at your local pharmacy. The most similar alternatives to mercury fever thermometers are battery and solar powered digital thermometers. These are alike in both price and use. These can all be used orally, rectally, or in the armpit. You should choose a thermometer that is easy to use and read.

If you are choosing a battery powered digital thermometer, choose one that contains a replaceable battery. Some of these thermometers do not have replaceable batteries. The battery is a button cell battery and may contain a small amount of mercury, so it should be recycled with a hazardous waste collection program. You can use Earth911's Recycling Locator Exit to find a mercury recycling center near you.

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Mercury Thermometer Cleanup and Disposal

If you break a thermometer while using it or if you improperly dispose of it, the thermometer will release mercury vapors that are harmful to human and ecological health.

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