Mercury Thermometer Exchange Program
Special Note on Broken Mercury Thermometers
The University of Minnesota Department of Environmental Health and Safety has developed a mercury thermometer exchange program to help eliminate mercury and its associated health and environmental hazards. The USEPA has identified mercury as one of their waste minimization priority chemicals, making the reduction of mercury a priority. The reduction in use of mercury is not only a U.S. priority, but is also an international priority. Mercury reduction is especially important to Minnesotans as many of the 10,000 lakes for which we are known are showing degradation in terms of mercury in fish populations. Other benefits include a reduction in costs associated with the cleanup and disposal of mercury and contaminated equipment, and less down time in research and teaching labs as spills are cleaned up.
The Department of Environmental Health and Safety will provide a one-for-one exchange of mercury thermometers for non-mercury thermometers. These non-mercury thermometers meet accuracy standards established by the National Institute of Standards and Technology (NIST). Just order the non-mercury thermometers from U Stores using the part numbers provided and they will be delivered to you. DEHS will then come to your location and collect the corresponding mercury thermometers. If you want to give up more than you replaced, that's fine too. You or your department will not be billed for exchanging thermometers.
The blue spirit thermometers listed contain non-toxic isoamyl benzoate and dye. The science and development of non-mercury thermometers have made great improvements over the past few years. However, although their separation rate is now equal to or better than mercury thermometers, the manufacturer and distributor still recommend storing them in the upright position to prevent column separation.
There are non-mercury thermometers with temperature and accuracy ranges equal to most mercury thermometers. An exception is on the high end of the temperature scale. Typically, 260° C is the typical limit for non-mercury thermometers. If scientific procedures cannot be performed with non-mercury thermometers, Teflon coated mercury thermometers should be used. The Teflon coating will help to reduce releases of mercury should a thermometer be broken.
Non-mercury thermometers have scale divisions equal to mercury thermometers. Most range from 0.5° to 1° C. Accuracy limits for non-mercury thermometers below 150° C are also compatible with mercury thermometers; accuracy is typically ± 1° - 2° C. For thermometers that have a high range of 260° C, accuracy below 100° C is ± 1°-2° C for both mercury and non-mercury thermometers. Above 100° C mercury thermometers have an accuracy range of ± 1.5° C, while non-mercury thermometers have an accuracy limit of ± 3° C.
All of the non-mercury thermometers listed meet NIST standards.
The blue spirit non-mercury thermometers are non-toxic and environmentally safe. The broken glass should be placed in a sharps container to prevent injury. The remaining liquid can be cleaned up with soap and water. NOTE: red spirit non-mercury thermometers may contain hazardous chemicals, such as kerosene or toluene. Collect these and manage as hazardous waste.
Understanding the different classifications of thermometers and how to use them is essential for accurate temperature measurements. The following information is provided to help promote accuracy and repeatability.
Total immersion thermometers indicate the actual temperature when the bulb and the entire liquid column are exposed to the temperature being measured. To permit reading, typically one inch or less of the liquid column should be exposed. These thermometers can also be totally submerged in liquid or placed in a freezer.
Partial immersion thermometers indicate the actual temperature when a specified portion of the stem is exposed to the temperature being measured. A partial immersion thermometer will usually have an inscription stating the required depth or a ring inscribed on the stem, which indicates the depth.
Note: Total Immersion thermometers can be used as partial immersion if correction factors are known and used to calculate the temperature.