Before You Tear it Down, Get the Mercury Out
Recommended Management Practices for Pre-Demolition Removal
of Mercury-Containing Devices from Residential Buildings
Mercury can be found in various devices in residential buildings. When a mercury-containing product breaks and the
mercury is spilled, the exposed mercury can evaporate and become an invisible, odorless toxic vapor. To prevent
mercury releases, these products should be used and stored safely, and managed properly at the end of their useful
lives. This fact sheet specifically addresses pre-demolition removal of mercury-containing gas pressure regulators,
mercury-containing boiler heating systems, and thermostats. For information on proper removal and management of
other mercury-containing products in homes, go to www.epa.gov/osw/hazard/tsd/mercury/con-prod.htm.
Mercury-Containing Gas Pressure Regulators
Issue: Some homes that were built prior to 1968 have a mercury-
containing gas pressure regulator adjacent to the gas meter. Most
of these devices were manufactured and installed in the 1940s and
1950s, but a few were manufactured and installed in some areas as
late as 1967. These devices contain approximately two teaspoons
of mercury. Mercury spills have sometimes occurred during
improper removal of these devices, causing a potentially significant
health risk and resulting in costly cleanups.
Recommended Management: Mercury-containing gas pressure
regulators should be removed only by qualified gas company
personnel. Local government entities planning to demolish
residential buildings (or anyone planning to demolish any building)
having gas pressure regulators or other gas equipment should
inform the local gas company of their proposed demolition
schedule at least two
A gas pressure regulator, adjacent to a gas meter, with
the location of the mercury cup identified.
weeks in advance of
demolition. This notice will enable the gas company to ensure that gas service
is turned off, protect underground natural gas pipes and infrastructure from
damage, prevent gas leaks, and coordinate the proper removal and disposal of
any mercury-containing gas pressure regulators prior to demolition.
REMINDER: Call 811 before you dig to identify the location of gas lines!
World War ll-era mercury-containing gas
pressure regulator. (Photo courtesy of the
American Gas Association.)
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Mercury-Containing Boiler Heating Systems (e.g., Honeywell Heat Generators)
Issue: Some homes with an old boiler heating system may have a Honeywell Heat
Generator (also called a mercury seal generator), which was invented in 1904 to
improve home hot-water heating systems. These devices may be found near the
boiler in the basement or near a radiator on an upper floor. They contain several
fluid ounces of mercury. Mercury spills can occur as a result of improper removal of
these devices. A spill can require a significant cleanup effort: in April 2011, EPA's
Region 10 Superfund Program responded to a mercury spill at a home where an old
1920s boiler had been improperly removed, resulting in a spill of about 4 fluid
ounces of mercury.
Recommended Management: Prior to demolition, Honeywell Heat Generators
should be removed in a manner that ensures no mercury is released from the unit.
Remove the unit intact, as seen in the photo. Then, place the entire unit into a large
plastic bag, always keeping the unit in a vertical position. Take the unit to a local
household hazardous waste facility or hire a professional environmental consulting
company, both of which have trained personnel who can handle and dispose of
mercury appropriately.
A mercury-containing Honeywell heat
generator may be connected to old
boiler heating systems.
Mercury-Containing Thermostats
Issue: Some thermostats contain mercury switches. Mercury is
contained in one or more glass bulbs inside the thermostat. There is a
risk of a mercury spill if the item is broken.
Recommended Management: Mercury-containing thermostats
should be removed, with the covers replaced for safety, and properly
disposed prior to demolition. Your county or solid waste
management district may already operate a thermostat recycling
program. If not, they can begin one or you can find a recycler near
you by contacting the Thermostat Recycling Corporation (TRC). TRC
will provide a collection bin for intact thermostats (with the cover
attached). The filled bin is shipped back to TRC free-of-charge and
Thermostats with mercury switches
showing glass ampoule containing mercury
(Image courtesy of Vermont Department of
Environmental Conservation.)
TRC will replace it with an empty collection bin. Communities interested in collecting thermostats from their residential
building demolition program should contact TRC directly about potential collection options. See
www.thermostat-recycle.org for more information about TRC's thermostat recycling collection program or email TRC at
trc@thermostat-recycle.org.
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