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Mercury Thermometer Exchange Program

We are working to get elemental mercury out of UVM laboratories as well as the environment. You can help us by swapping your mercury thermometers for non-mercury thermometers. Contact us at safety@uvm.edu and let us know what you need for replacement. The choices are:

Temperature range: -20 to 110 degrees Celsius or -10 to 260 degrees Celsius

Partial or total immersion:

  • Total immersion thermometers are designed to indicate temperatures correctly when the bulb and the entire liquid column are exposed to the temperature being measured.

  • A partial immersion thermometer usually has a line or mark at the immersion distance from the bottom. It reads correctly when the bulb and the liquid column to that line are exposed to the temperature being measured and the emergent stem is at ambient or surrounding temperature.

More about the UVM mercury thermometer exchange program

In January 1997, Environmental Safety Facility technicians became aware of a growing problem; an increase in the number of broken mercury thermometer spills on campus. Not only was this potentially dangerous, but cleaning up the debris is time consuming, and the disposal costs are expensive. Highlighting this increase in broken thermometers, the University had been required by the EPA to have in place a chemical waste minimization program. Since opening in January 1994 as a TSD (Treatment/Storage/Disposal) facility, we had seen an increase in chemical waste due primarily to our efforts at cleaning up old chemicals left over in chemistry laboratories. Documenting that the University was actively engaged in reducing the amount of chemical waste became one of the goals of the ESF. Reducing the number of mercury thermometers on campus became one way to show initiative in that direction. The vehicle we chose for this project was UVM ChemSource, the chemical and safety equipment distribution program for the campus administered through the ESF.

Mercury as a Hazard

Mercury compounds have been used throughout history to chase away evil spirits, change base metals into gold, and as medicine. Of course, the usefulness of mercury is limited by it's poisonous nature. As with most chemicals there are two types of mercury poisoning--acute and chronic. Acute mercury poisoning results from the ingestion of soluble mercury salts which corrode skin and mucous membranes. Mercury vapor aspirated into the lungs can cause severe pneumonia and death. Chronic mercury poisoning occurs through the regular absorption of small amounts of mercury. This condition is often a disease of workers in mercury mines, laboratories, and industries that use mercury. Organic mercury compounds, such as dimethyl mercury, are among the most dangerous.

Mercury vapors are colorless, odorless, tasteless, and toxic. When mercury thermometers break, laboratory and clean-up personnel are exposed to dangerous mercury fumes. An incomplete clean-up creates the threat of long term exposure to mercury fumes. Furthermore, drops of the liquid metal can become lodged in floor cracks and behind equipment. Depending on the amount spilled and the air movement within the laboratory, the mercury vapor concentration in a laboratory with "hidden" mercury spills may exceed safe limits. A spill is more dangerous when mercury thermometers break in ovens or incubators because mercury evaporates readily at high temperatures, creating high mercury concentrations.

Disposal of mercury thermometers and the contaminated clean-up materials generated by a spill is very expensive. Materials containing mercury are currently disposed of at a cost upward to $100 per gallon. Thus, one 55-gallon drum of mercury waste shipped for disposal, could potentially cost the University $5,500. Spill debris uses much more space than an intact thermometer, resulting in increased cost. Special clean-up procedures, such as dismantling an incubator or oven that has spilled mercury also increases costs substantially.

In the Beginning

Our initial search for replacement thermometers turned out to be a less than easy task. Most suppliers and vendors had very small selections of environmentally safe thermometers. The most common being the red alcohol thermometer, which we decided against mostly because the color did not meet our environmental perceptions. Early on we investigated a green spirit filled Enviro-Safe thermometer distributed by H-B Instrument Company. After several in-house tests and trial uses on campus, problems with column separation, thus accuracy, occurred, so we continued our search. We previewed various thermometer catalogs, trying to come up with a good selection of safe thermometers; our great wish being to get a good price. We had decided that the initial exchange would be funded through our operational budget. We turned to one of our campus scientific vendors, Krackeler Scientific http://ksionline.com to help us in our search. Eventually we came upon a blue spirit Ever-Safe thermometer distributed by Ever Ready Thermometer Company http://www.ertco.com of West Paterson, New Jersey.

Learning of our project the Chemistry Department immediately put in an order for replacement thermometers to be used by it's undergraduate and graduate laboratories. We eventually stocked -20/110 deg. Celsius (both total and partial immersion),and -10/260 deg. C, partial immersion thermometers--both in 1.0 scale divisions, as well as -1/101 deg. Celsius thermometers marked off in .2 scale divisions. Choosing between a partial or total immersion thermometer created further problems.

Partial or Total Immersion?

Total immersion thermometers are designed to indicate temperatures correctly when the bulb and the entire liquid column are exposed to the temperature being measured. A partial immersion thermometer usually has a line or mark at the immersion distance from the bottom. It reads correctly when the bulb and the liquid column to that line are exposed to the temperature being measured and the emergent stem is at ambient or surrounding temperature.

Step By Step

We needed to create an effective way to publicize the "swap." We hired a graphic artist to develop a flyer for us that would grab the attention of laboratory faculty and staff--not always an easy task. We spent a fair amount of time selecting an appropriate logo and colors for this project, but eventually came up with a design we liked. Fortunately we had already gone through some of the details beforehand when UVM ChemSource first got underway.

By the Spring of 1997 we were ready to introduced our "Mercury Thermometer Swap." Surveys were sent to individuals and departments that we felt would most likely have significant numbers of mercury thermometers to exchange, one-for-one, and cost free. We also included several articles announcing the thermometer "swap" in Safety News, the University's chemical safety and health newsletter. As envisioned the initial cost would be covered by our operational budget, but we had no idea how many thermometers actually existed on campus. From the start we had expected a relatively small exchange, and were slightly overwhelmed by the initial request from the Chemistry Department for over 800 thermometers. By January 1999, we had exchanged over 1,450 thermometers--with the bulk of them going to the Chemistry Department, and the remaining thermometers swapped or sold to other campus laboratories. Those investigators and laboratories that didn't have mercury thermometers to exchange could buy our non-mercury thermometers at greatly reduced cost. We instituted a 90-day return policy during which we stored the mercury thermometers at the facility until we received favorable, or no feedback concerning the use of the new thermometers. After that time we would declare the mercury as hazardous waste. We later sent a customer survey to the "swap" participants for their comments about the exchange in general. We eventually filled one 55-gallon barrel with these thermometers at a disposal cost of about $3,700.

More Precise, Sharing the Cost

We received several requests for specialized thermometer replacement, and supplying these would cost far more than our budget could handle. We were able to get a promise from the Chemistry Department to help offset the increase in cost, with an agreement to share those costs over the next two fiscal years. In particular, the Chemistry Department's required thermometers marked off in .1 divisions. Upon placing an order with ERTCO, we were told that these were no longer being made, and were being replaced with .2 division thermometers. We had to verify how accurate these thermometers would be for general laboratory purposes. We talked directly with an ERTCO technical sales advisor and were sent calibration certification results to review. The .2 division thermometers performed well, with some decree experienced at the higher end of the temperature scale.

Overview

In general our campus initiative to replace mercury thermometers with more environmentally safe thermometers went well. This "short term" project became more complex then we initially thought. The program added yet another dimension toward meeting our overall waste minimization objectives, while helping to bring about an increased awareness of the dangers involved with mercury. The campus has been given a non-mercury thermometer alternative to replace those "unloved" mercury thermometers, and has also helped reduce the University's overall clean-up and disposal costs. It is a small but hopefully model program for continued thermometer swaps, and waste minimization strategy.

Last Updated: October 12, 2006