Beginning March 1, 2011, the National Institute of Standards and Technology (NIST) will no longer provide calibration services for mercury thermometers. The cessation of the mercury thermometer calibration program marks the end of an era at NIST, which has provided the service since the doors opened in 1901. The closing of the program is part of a larger effort, in collaboration with the U.S. Environmental Protection Agency (EPA) and a number of professional standards organizations and environmental and industry groups, to phase out the use of mercury thermometers altogether.
Mercury is a potent neurotoxin. Elemental mercury is found in thermometers and used in a number of industrial processes such as gold mining. Once released into the environment, mercury makes its way into streams, rivers, and finally the ocean. The mercury is absorbed by sea life and accumulates in the larger fish that humans like to eat. This is the main source of mercury poisoning in humans today.
While many industries follow ASTM standards that stipulate the use of mercury thermometers, these standards have fallen behind the states, many of which have outlawed the sale and transport of mercury thermometers. Presently about 300 of the approximately 700 standards have been amended to allow for the use of both mercury-free liquid-in-glass and digital thermometers.
According to NIST researcher Dawn Cross, each of these ASTM standards is reviewed on a rolling basis. She estimates that all the standards will have been amended to include detailed procedures for making the switch to mercury thermometer alternatives within three years.
"One of our major activities is fielding calls from industry and explaining the science of how they can make the switchover," says Cross. "Change always brings confusion and apprehension, but in every case there is an alternative thermometer to suit the measurement need. It's like learning to use a new cell phone or drive a c
|Contact: Mark Esser|
National Institute of Standards and Technology (NIST)