Sustainable Hospitals
Mercury Reduction
Best Management Practices for
Mercury-containing Products in the Hospital

Thermostat Probes in Gas Appliances
Mercury-containing thermostat probes may be found in several types of gas-fired appliances that have pilot lights, such as ranges, ovens, clothes dryers, water heaters, furnaces or space heaters. They are usually present as part of the safety valve that prevents gas flow if the pilot light is not lit. The metal probe consists of a metal bulb and thin tube attached to a gas-control valve. The bulb of the probe projects into or near the pilot light. The mercury is inside the tube and expands or contracts to open and shut the valve.
A mercury thermostat probe may also be part of the main temperature-controlling gas valve. In this application, the probe is in the air or water that is being heated and is not directly in contact with any flame. These are typically found in older ovens, clothes dryers, water heaters and space heaters.
If there is a question about the mercury content of a thermostat probe, obtain this information from the manufacturer.
Alternatives for mercury-containing thermostat probes in gas appliances
Non-mercury thermostat probes are also used in the appliances listed above. They are:
  • Sodium/potassium thermostat probes
  • "Dissimilar metals" thermostat probes
Recycling/disposal of mercury-containing thermostat probes in gas appliances
Remove thermostat probes from the appliances to be discarded and store them along with the mercury-containing electrical equipment described in the section on Electrical Equipment. Place them in a covered container that is labeled as to the type of equipment being stored. The container could be located in the supply room of the hospital where the replacements are stored until it is full and ready for transport to the hospital's designated hazardous waste collection point.
Management Practices

Fever Thermometers
Gastrointestinal Tubes
Dental Amalgam and Mercury
Laboratory Chemicals
Pharmaceutical Products
Cleaners and Degreasers
Electrical Equipment
Thermostat Probes in Gas Appliances
Industrial Thermometers
Pressure Gauges
Storage Areas
Hospital Employee Health and Safety
Related Topics:
Case Studies
Why is mercury a problem?
How to establish mercury pollution prevention in your hospital.

Best Management Practices for Mercury-containing Products in the Hospital
Mercury Reduction
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