IN.gov - Skip Navigation

Note: This message is displayed if (1) your browser is not standards-compliant or (2) you have you disabled CSS. Read our Policies for more information.

Recycle Indiana

Recycle Indiana > Mercury > Mercury Related Programs at IDEM > Mercury Reduction Outreach for Publicly Owned Treatment Works (POTW) > Mercury Reduction Outreach: HVAC-R Mercury Reduction Outreach: HVAC-R

The HVAC-R industry has a long history of working with mercury-containing items, especially thermostats. Mercury is a good and reliable conductor of electricity. However, mercury must be disposed of properly in order to protect human health and the environment.

Because mercury can be a solid, liquid, or a vapor, properly managing mercury can be a tricky task. When mercury thermostats are thrown into the trash, they are either sent to an incinerator or to a landfill. When incinerated, the liquid mercury found in thermostats turns into a vapor that is released into the air. Likewise, if mercury containing devices are disposed in a landfill, they could be broken, allowing the liquid mercury to escape, vaporize, and be vented into the atmosphere through pipes that were once thought to only emit methane. The airborne mercury is then deposited to our lakes and steams when it rains, where some of the mercury is converted by naturally occurring bacteria into methylmercury, a highly bio-accumulative compound that contaminates our water and our fish.

When mercury is allowed to escape down the drain, it comes in contact with water and becomes a contaminant that must be removed by your local wastewater treatment plant. Once in the water, it can be difficult and costly to remove or to reduce mercury to safe limits.

Where can mercury be found in the HVAC-R Industry?

Mercury can be found in many products used by the HVAC-R industry. The following are some of the commonly used items:

  • Thermostats
  • Switches
  • Relays
  • Sensors
  • Thermometers

Mercury may also be found in sewer pipes from past management practices. Mercury can settle at a low point, such as a sump or trap, and remain in the pipes of a facility for many years. Often, the slow dissolution of the mercury in a sump, trap or pipe is enough to cause exceedance of mercury limits in wastewater, even after best management practices are implemented. Hot spots in a facility's piping may appear where laboratories or equipment maintenance areas were located. Whenever traps or sumps are moved or cleaned, the solid contents should be treated as a hazardous waste unless proven otherwise.

Why the concern?

Although mercury performs many useful functions, it is toxic and can impair the way we see, hear, and function.

In the environment, a percentage of mercury undergoes a biological/chemical process and is converted to methylmercury, which is a more toxic form of mercury.

Mercury poisoning can attack the central nervous system in humans. Women of child-bearing age and children, especially those under the age of 6, are most susceptible to mercury poisoning.

Stricter Regulation:

Wastewater treatment plants are facing increased regulatory attention for levels of mercury in the wastewater they treat and ultimately discharge into Indiana waters. As a result, treatment plants throughout the state need the cooperation of business, industry and citizens to minimize the amount of mercury escaping down the drain.

What can the HVAC-R industry do to help?

You can help by joining IDEM's Mercury Thermostat Reduction & Recycling Program. This program seeks to reduce the amount of mercury used and includes a recycling program for mercury-containing thermostats. The program is free to HVAC-R contractors. There is a one-time fee of $15 for wholesalers.

For more information on IDEM's Mercury Thermostat Reduction & Recycling Program, visit the following Web sites:

  • Information for Contractors
  • Information for Wholesalers

Other Mercury-Containing Items

  • Complete a mercury inventory of your facility by using the Mercury Checklist [DOC];
  • Phase out mercury-containing products and equipment, when possible;
  • Properly recycle or dispose of mercury-containing items; and
  • Implement a mercury-free purchasing policy.

Other Resources

For additional information call (800) 988-7901 or (317) 232-8172