Have you had your current thermostat for 10 years or more? If so, most likely it is a mercury thermostat. Though the United States Environmental Protection Agency states that, “Mercury thermostats are unlikely to break or leak mercury while in use…” it is important to note that mercury is still a harmful substance. That is why when mercury thermostats are replaced with newer thermostats, such as digital and automatic thermostats, the old mercury thermostats must be disposed of in a proper manner.
Professional heating and cooling companies such as Flame, can correctly dispose of mercury thermostats. However, the EPA also gives resources for disposing of these thermostats on your own. They recommend contacting your local collection program to find out information for this, or checking out earth911.com. This is not something that should be done without the proper research, and when in doubt, contact a heating and cooling company for help!