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Stanford Report, July 12, 2000

New program aims to eliminate mercury thermometers


A mercury thermometer exchange program that debuted at Stanford Medical School earlier this year has been extended to the rest of the university.

The pilot program was designed to collect and replace -- for free -- potentially hazardous mercury thermometers with environmentally friendly ones.

The exchange was launched in tandem with the opening of the Center for Clinical Sciences Research (CCSR), where during March and April, thermometers containing a total of 56 grams of mercury -- enough to pollute nearly 300 million gallons of San Francisco Bay -- were replaced.

David Silberman, manager of the school's health and safety program, said the CCSR venture was an attempt to test the replacement program on a small scale before asking the entire campus to make the switch to non-mercury thermometers (except where absolutely needed).

Tracy L. Ingebrigtsen, an environmental quality engineer with Facilities Operations, coordinated the program with Silberman. It was underwritten by the Environmental Health and Safety (EH&S) department, which this month gave the go-ahead to support a campus-wide exchange project.

Broken thermometers pose a safety hazard to faculty, staff and students in laboratory areas and to the local environment, Silberman said, adding that "the absence of mercury thermometers also reduces our regulatory risk and can potentially decrease the cost of renovation projects."

Silberman explained that mercury-free environments don't require the special disposal features in the design of new construction. "There's a lot of money and time saved down the line," he said.

Ingebrigtsen said that when a mercury thermometer breaks and EH&S staff is dispatched to clean up, the cost is about $75 per incident.

The replacement thermometers contain biodegradable liquid and dye and can be used in incubators, water baths and other applications. They differ from their mercury counterparts in that they must be stored upright to keep the liquid inside from separating. Their temperature range is from minus 100 degrees to 260 degrees Celsius, or minus 148 degrees to 500 degrees Fahrenheit.

During the replacement campaign at CCSR, 115 mercury thermometers were exchanged. The half-gram of mercury found in one thermometer is enough to pollute five million gallons of Bay water, Ingebrigtsen said. Mercury is volatile at room temperature with vapors that are colorless, odorless, tasteless and toxic.

Those making exchanges have several models of thermometers to select as replacements. The retired mercury thermometers will be taken to a recycling plant.

Exchanges can be made by appointment or at an arranged exchange event. For more information, contact Ingebrigtsen at or 723-9747. Or visit and click on the link for the mercury thermometer exchange program.

Stanford's exchange program is for campus-based thermometers only. For information about exchanging household mercury thermometers, call the Regional Water Quality Control Plant, which serves Palo Alto, East Palo Alto, Los Altos, Los Altos Hills, and Mountain View, at 329-2598. SR