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Weights and Measures Connection, Vol. 4 , Issue 1 Page 1

March 1, 2013

NIST Launches New Website to Educate Industry About 

Alternatives to Mercury Thermometers

Byline: Mark Esser, NIST

As part of a larger effort to reduce the amount of mercury, a potent neuro-toxin, in the environment,the

National Institute of Standards and Technology (NIST) has launched a new website

(www.nist.gov/pml/mercury.cfm) to help industry scientists and engineers decide the best temperature

measurement alternative for their purposes. The website also includes information about myths

pertaining to mercury and temperature measurement and how to safely package and recycle mercurycontaining products.

NIST stopped providing calibration services for mercury thermometers on March 1, 2011. This was

motivated in part by NIST’s work with the Environ- mental Protection Agency to eliminate as many

sources of mercury in the environment as possible.

According to Greg Strouse, leader of NIST’s temperature, pressure and vacuum programs, mercury

thermometers are neither a superior nor a standard method for measuring temperature.

“We haven’t used mercury thermometers as a calibration standard since 1927 when the platinum

resistance thermometer standard was adopted,” says Strouse. “Our goal with this new website is to

show that there is a temperature-sensing technology that willsatisfy their needs as well as, or betterthan,

a mercury thermometer, all without the added liability of containing a neurotoxin that is hugely

expensive to clean up if released into the environment.”

According to NIST researcher Dawn Cross, industrial scientists commonly object to replacing their

mercury thermometers because they have grown accustomed to getting the same answer from their

mercury thermometers over the years, even if it is less accurate than can be provided by modern digital 

thermometers.

“Some people who are used to using mercury thermometersthink that they define temperature, and this 

simply isn’t true,” Cross says. “Graduations on a piece of glass filled with a fluid can never give as

accurate a reading as a digital thermometer, based on how the conductivity of metals change as a 

function of temperature,something we know and can characterize very, very well.”

Cross points out that other thermometers based on the principle of thermal expansion of a fluid, such as 

alcohol, are not hopelessly inaccurate. In fact, they are as accurate as mercury thermometers and are 

suitable for some applications that don’t require stringent temperature control. For example, alcohol 

thermometers might be suitable for measuring the temperature of gasoline and other fuels, but they 
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would be unsuitable for monitoring the temperature of vaccines, the viability of which relies on strict 

control of their temperature.

Visit the website at www.nist.gov/pml/mercury.cfm for more information about how NIST can help your 

industry find an accurate, non toxic and environmentally benign alternative to mercury thermometers. 

Media Contact: Mark Esser, mark.esser@nist.gov, (301) 975-8735

Source: Tech Beat, June 12, 2012

Link to original article: www.nist.gov/public_affairs/tech-beat/index.cfm