The National Institute of Standards and Technology has launched a website to further educate industrial end-users about mercury in old temperature sensors and provide alternatives to their use.

Mercury is a potent neurotoxin, and NIST created the website to help industry scientists and engineers decide the best temperature measurement alternative for their purposes. The website includes information about myths pertaining to mercury and temperature measurement, and how to safely package and recycle mercury-containing products.

NIST stopped providing calibration services for mercury thermometers in 2011, motivated in part by NIST’s work with the Environmental Protection Agency to eliminate as many sources of mercury in the environment as possible.

Mercury thermometers are neither a superior nor a standard method for measuring temperature, according to Greg Strouse, leader of NIST’s temperature, pressure and vacuum programs.

“We haven’t used mercury thermometers as a calibration standard since 1927 when the platinum resistance thermometer standard was adopted,” Strouse says. “Our goal with this new website is to show that there is a temperature-sensing technology that will satisfy their needs as well as, or better than, a mercury thermometer, all without the added liability of containing a neurotoxin that is hugely expensive to clean up if released into the environment.”

Industrial scientists commonly object to replacing their mercury thermometers because they have grown accustomed to getting the same answer from their devices over the years, even if it is less accurate than can be provided by modern digital thermometers, says Dawn Cross, a NIST researcher.

“Some people who are used to using mercury thermometers think 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.”

Other thermometers based on the principle of thermal expansion of a fluid, such as alcohol, are not hopelessly inaccurate, according to Cross. In fact, they are as accurate as mercury thermometers and are suitable for some applications that don’t require stringent temperature control, she says. For example, alcohol thermometers might be suitable for measuring the temperature of gasoline and other fuels, but they would be unsuitable for monitoring the temperature of vaccines, the viability of which relies on strict control of their temperature.

Go to for more information about how NIST can help your industry find an accurate, nontoxic and environmentally benign alternative to mercury thermometers.