To Top of Page The following mercury-containing devices are found in many or most buildings,
and should always be removed prior to demolition. Doing so will generally be
the responsibility of the demolition contractor:
The following items are commonly found in many industrial and commercial settings, and in homes as well. These items should be removed prior to demolition, although in many cases it may not be the demolition contractor's responsibility to do so. For instance, mercury gas flow regulators should be removed by gas company personnel, and mercury-containing appliances should be dealt with by municipal programs or scrap dealers. In some cases, such as mercury-containing rubber floors or mercury in pipes, removal by a contractor with specialized experience may be called for. Mercury will need to be poured out of any device that cannot be moved or shipped without spilling mercury, as may be the case with some manometers and flow meters. Only contractors who are experienced with mercury and have adequate worker protections should pour mercury out of these devices.
Whenever you encounter a device that you are unprepared to handle, you must inform the building owner so that arrangements for proper handling can be made.
Description: Amount of Mercury:
From less than 10 milligrams to 50 milligrams per tube, depending on size and
model.
Alternative Devices:
Fluorescent lamps are an excellent lighting choice because they use
up to 50% less energy than other lamps. This reduces the amount of mercury produced
at the power plant, where mercury is given off by coal and oil combustion. Thus,
even though incandescent bulbs contain no mercury, their inefficient energy
use results in more mercury being released to the environment. However, it is
essential that fluorescent lamps are disposed of properly, so as not to allow
the mercury to enter the environment. The best disposal method is recycling.
A new type of long-life fluorescent lamp has been developed which contains such a small amount of mercury that it is no longer considered a hazardous waste. The typical fluorescent lamp has a lot of "extra" mercury in it because mercury loses its effectiveness over time due to physical and chemical reactions. This new lamp has a buffering system that blocks these physical and chemical reactions so that the lamp contains less than 10 mg of mercury. These lamps should still be recycled.
How to Locate the Device:
Fluorescent lamps are located in offices and businesses. The most common
style is the long, skinny tube used in overhead indoor lighting. Compact globe
styles are also used in homes and offices.
Safe Removal:
Caution should be taken to avoid lamp breakage. Breakage may result
in mercury released into the environment. Lamp recyclers also generally require
that the lamps arrive unbroken. The best way to protect them is putting old
lamps into the boxes the new lamps came in or boxes from a lamp recycler.
Most bulbs are removed in one of two ways:
The bulbs are very delicate and should be carefully removed and then placed in boxes for disposal. Often, mercury recyclers rent or provide cylindrical cardboard containers for fluorescent bulbs.
Safe Disposal:
Location & Description:
Most HID lamps are used in security, outdoor, or warehouse applications. Probable
locations are parking-lot light poles, warehouse rafters, and the outside walls
of buildings. There are three types of HID bulbs; Mercury vapor, high pressure
sodium, and metal halide. All three contain mercury.
Amount of Mercury:
Anywhere from 20 to 250 milligram are found in the average HID lamp.
Alternative Devices :
Until recently, there were few alternatives for mercury containing HID lamps,
which provide high intensity, energy-efficient light. However, mercury-free
HID lamps have been developed recently, and are becoming increasingly available
on the market. It is extremely important to properly recycle existing mercury
lamps to keep the mercury used out of the environment.
Safe Removal:
Depending on the type of light, screwdrivers, nutdrivers or wrenches
may be necessary. Usually the best way to remove the light is to remove the
whole lighting unit. The ballasts and batteries usually also contain PCBs and
a toxic type of battery acid that should also be handled properly. The average
time to remove these lights is around 90 seconds.
Safe Disposal:
Source: Department of Environmental Engineering, University of Florida.
Description:
Mercury is contained in temperature-sensitive switches and mechanical tilt switches.
Mercury tilt switches are small tubes with electrical contacts at one end of
the tube. As the tube tilts, the mercury collects at the lower end, providing
a conductive path to complete the circuit. When the switch is tilted back, the
circuit is broken. Reed switches are small circuit controls that are used in
electronic devices. Their electronic contacts are wetted with mercury to provide
an instantaneous circuit when the switch is closed and then an instantaneous
current interruption when the circuit is broken. A third type,
float switches, are used in sump pumps and bilge pumps to turn the equipment
off when water reaches a certain level.
How to Identify:
A mercury tilt switch is usually present when no switch is visible. They are
used in thermostats, silent light switches, clothes washer lids, and chest freezers.
Float switches, on the other hand, are visible.
Amount of Mercury:
About 3.5 grams of mercury are contained in a small electrical switch. Industrial
switches may contain up to 8 pounds of mercury.
Alternative Devices:
Alternatives to mercury switches include hard-contact switches, solid-state
switches, electro-optical switches, inductive sensors, capacitive sensors, photoelectric
sensors, and ultrasonic sensors.
How to Locate the Device:
Mercury tilt switches are used in a number of ways including light
switches, chest freezers, and washing machine lift covers.
Switches are typically found in furnace controls, light and traffic controls, lab equipment, high voltage industrial equipment, and motors. If a switch is suspected to be a mercury switch, remove the cover plate and look for the word "TOP" stamped on the upper end of the switch. If it is present, it is most likely a mercury switch. Remove the entire switch using screwdrivers and wirecutters and place it in a suitable container for storage and shipment.
Washing machines made before 1972 could contain a mercury switch, but most of these machines have already reached the end of their usable life and have already entered the wastestream.
Safe Removal:
Remove switches from appliances very carefully so as not to release
any mercury into the environment.
Safe Disposal:
Description:
Mercury-containing thermostats use mercury tilt switches.
How to Identify:
Most Thermostats, other than electronic thermostats, contain mercury.
To determine if a thermostat contains mercury, remove the front plate. Mercury-containing
thermostats contain one or more small mercury switches.
Amount of Mercury:
About 3 grams of mercury is in each mercury tilt switch. Most thermostats have
one switch; some have two, and up to six switches are possible.
Alternative Devices:
Programmable electronic thermostats are mercury free, and they are
more energy-efficient than the mercury models. Look for programmable electronic
thermostats that have the Energy Star label.
How to Locate the Device:
Thermostats are generally mounted on walls and easily found.
Safe Removal:
Remove the entire thermostat using a screwdriver and a pair of wirecutters
and store safely. DON'T remove the switches from the thermostat or dismantle
the thermostat.
Safe Disposal:
Store the entire thermostat in a marked container until it can be
sent for proper disposal. In many states, the Thermostat Recycling Corporation
operates a recycling program utilizing heating, ventilation and air conditioning
(HVAC) wholesalers; eventually this program will be in operation nationwide.
The wholesalers consolidate thermostats from contractors and send them to recyclers;
only whole thermostats are accepted. Contact your HVAC wholesaler to find out
whether you can drop off thermostats. If the Thermostat Recycling Corporation
program is not yet operating in your state, inquire with your state or local
hazardous waste program for information about where you can send mercury thermostats
for proper disposal.
Description:
Mercury light switches were manufactured prior to 1991. Mercury light switches
are sometimes encountered in older buildings. These devices look like typical
wall switches, but they do not make the audible "click" sound when activated.
They operate on the principal of liquid mercury in a metal encased glass button
that completes the electrical circuit when the switch is lifted up, submerging
an electrical contact point. These switches are often referred to as "silent
switches."
How to Identify:
Mounted on walls near doors and walkways.
Amount of Mercury:
About 2 grams
Safe Removal:
Remove the whole switch from the wall very carefully as not to release
any of the mercury from the switch.
Safe Disposal:
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Be aware of potential mercury containing switches within the heating or cooling unit. Consult the manufacture for information concerning the potential for mercury release when disposing of the unit.
Name: Elemental Mercury and Mercury Compounds
Description:
Bottle or container labeled as mercury or with the periodic symbol 'Hg', possibly
in a dentist's office, laboratory or in an industrial business. Properties of
elemental mercury are liquid at room temperature, but with a metallic and shiny
appearance, conductive, and highly volatile.
CAUTION! If a substance appears to be mercury, but is not labeled as such nor labeled as another material, contain the material and have a laboratory test the material to conclude what the substance is. When handling the unidentified material, take all safety precautions in handling the material so as to not come in contact with the material nor to introduce the material into the environment. If a spill does occur, follow the proper safety guidelines to clean up and contain the spilled mercury.
Storage of Elemental Mercury:
Chemical Compounds and Alternatives:
Name: Chest Freezers
Description:
Some chest freezers made with an internal lid light have a mercury switch incorporated
in the light socket. If a chest freezer has a light in the cover and no visible
mechanical switch, then it contains a mercury switch. This device senses when
the lid is raised and turns on the light. The appliance recycling center estimates
that around 190,000 freezers with this type of device in them were sold in the
United States. Various types of cooling and refrigeration equipment used in
restaurants and industrial applications contains mercury switches as well.
How to Identify:
The person or company responsible for recycling or disposal of the appliance
must dispose of the mercury properly. If you think you have come across a freezer
with this type of switch, the following steps will allow you to remove the switch
and store it properly.
Amount of Mercury:
The freezer light switch contains about 1 gram of mercury.
Safe Disposal:
Description:
The metal flame sensor consists of a metal bulb and thin tube attached to a
gas-control valve. The mercury is contained inside the tube and expands or contracts
to open and shut the valve.
How to Identify:
Several types of gas-fired appliances that have pilot lights, like ranges, ovens,
clothes dryers, water heaters, furnaces, and space heaters use mercury-containing
flame sensors. Some non-mercury flame sensors have been used in these appliances,
but you should treat all sensors as if they contain mercury, unless you know
for sure that they don't.
Alternative Devices:
Electric flame sensors are mercury-free and have been used in some
appliances.
How to Locate the Device:
Most often, mercury thermostat probes are part of the safety valve
that prevents gas from flowing when the pilot light is not lit. In this case,
the bulb of the thermostat projects into or near the light. Mercury flame sensors
are also present sometimes as part of the main temperature-controlling gas valve.
In this operation, the sensor would be located in the air or water that is being
heated, and not in direct contact with the flame. These are typically in older
ovens, clothes dryers, water heaters, and space heaters.
Safe Removal:
Remove the entire flame sensor unit from the appliance.
Safe Disposal:
Description:
Float switches are used at larger factories and sewage plants to maintain a
given level of liquid. The float switch is a round or cylindrical float with
a switch attached to it. The switch keeps the circuit closed until the float
reaches a certain height. Then, the mercury slides down, opening the circuit
and shutting off the pump.
Amount of Mercury:
Most of the switches contain other devices.
Alternative Devices:
New versions of float switches are mercury free.
How to Locate The Device:
Float switches are used in plants where levels of liquids such as water,
oil or sewage need to be monitored. If you are at all suspicious that the plant
handled large amounts of fluids, you need to look for them. Sometimes float
and level switches are hidden inside storage tanks and are not always visible.
When this is the case, follow electrical leads from the control unit to the
switch. Float switches usually have a large hollow float.(See Picture Above)
Safe Removal:
When you find the float, there will be a rod connected to it. This is a control rod that connects to the control box. Once you are at the control box, open the front and you should see a mercury filled glass ampoule. This is the only thing containing mercury in the float switch.
Safe Disposal
Description:
Flow meters are used for measuring water flows and steam pressure at larger
plants, such as water and sewage plants, power stations and heating plants.
How to Identify:
A variety of different sizes and shapes can be found. Ask the personnel at the
plant for help and ask how much they know about the equipment. If the equipment
has been replaced and or repaired, check drains located nearby for possible
contamination.
Amount of Mercury:
Always assume that the flow meter does contain mercury until you can find the
facts about the manufacturer and the model. Some models do contain large quantities
of mercury - 5 kilograms and more.
Safe Removal:
If the device is small enough to be contained in a airtight package, consult
a mercury recycler about how to ship properly to avoid spillage.
If the device is too large to be shipped in an airtight container (such as the devices pictured above), the mercury will need to be poured out of the device into a separate container. Given the potential for spills, such operations require that you are prepared to contain possible spills, that you have appropriate airtight, unbreakable containers for the mercury, that you have personal protective equipment on hand, that you provide adequate ventilation, and that Occupational Health and Safety regulations are followed. Thus, the typical demolition contractor should inform the building owner when such a device is encountered, so that a contractor with the necessary equipment and experience can remove the device.
Safe Disposal:
The mercury drained from the device, as well as the parts of the meter that
have been in contact with mercury should be regarded as mercury waste and properly
disposed of with a mercury recycler.
Description:
Some gas ranges use a pilot light ignition. Pilot light ranges require a mechanical
safety device to detect whether the pilot light is on and shut off the supply
of gas to the burner when the pilot light is not burning. If the ranges did
not have this safety device, unignited natural gas could leak into the home
and create a very dangerous situation. The device most often used is called
a mercury flame sensor. They are made of a bulb and bellows filled with mercury.
The bulb is located in the pilot light flame. When the pilot light is on, the
heat from the flame turns the mercury into vapor which expands the bellows and
opens the gas valve. Switches similar to these are used on basically all gas
pilot light operated appliances. Some of these switches are mercury-free but
have the same or similar appearance to ones that contain mercury. These devices
need to be removed when the range is going to be destroyed. Appliances with
electronic ignition and a Hot Surface Ignitor do not have mercury flame sensors.
Some ovens contain mercury switches. The switch may be found on the door, it
is used to turn on the light when the door is opened. Oven thermostats were
made of mercury until the mid 1970s. This was another capillary and bellows
full of mercury that expanded and contracted as the temperature rose and fell.
This device was connected to a switch that controlled the main oven burner.
How to Identify:
The person or company responsible for recycling or disposal of the appliance
must dispose of the mercury properly. The mercury containing sensor is located
on the burner. The sensor is made of three components: a safety valve sensor
bulb; a safety valve capillary tube and a gas safety valve control. The light
switches are very easy to find. They are located along the inside of the door
and are connected to the oven with a clamp. The capillary tubes are long, thin
tubes leading from the safety valve to the oven burner. All flame sensors and
thermostat controls with mercury are made with stainless steel.
Amount of Mercury: Most sensors contain about 2 grams of mercury. Most switches contain 1 gram of mercury.
Alternative Devices:
One alternative is the electronic ignition range. This is fueled by gas the
same way the pilot light ones are, only it does not have a constant running
pilot light. There are no mercury containing devices in the electric ignition
gas ranges, so they are a good alternative. It is not a good idea to convert
a pilot light range to an electric ignition range. The parts are expensive and
many times it requires extensive wiring to power the electric ignition.
Safe Disposal:
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Description:
Manometers and barometers are used for measuring air pressure.
How to Identify:
All these devices will have a gauge for reading air pressure.
Amount of Mercury:
Varies. Typically 100 - 500 grams. Can be more.
Alternative Devices:
Aneroid and electronic manometers, analog gauges (also known as vacuum gauges).
How to Locate the Device:
Typically found mounted on walls in medical facilities (for measurement of blood
pressure), in dairy barns (attached to a milking machine), and in a variety
of industrial operations. Mechanics shops have mercury-containing carburetor
synchronizers, multi-column manometers used by mechanics who service motorcycle
engines and outboard motors.
Safe Removal:
To safely remove the manometer or barometer, remove the entire device from
the machine it is attached to. Do not tip, because some manometers will spill
mercury when tipped.
Safe Disposal:
Put the entire unit upright into an airtight, labeled container. Consult
a mercury recycler about how to ship the device to the recycler.
(NOTE: If a manometer is present, look for containers of elemental mercury to refill the manometer. Click here for more information on elemental mercury.)
Name:
Mercury Gas Flow Regulators
Description:
Some homes that were built prior to 1961 contain a mercury regulator attached
to the gas meter. This device does not create a spill risk while in service,
but some mercury spills have occurred during removal.
How to Identify:
The mercury regulator is attached to the gas meter.
Amount of Mercury: Roughly 100 grams.
Safe Removal:
These devices should be removed only by qualified gas company personnel.
Contact the local gas company to ensure proper removal of these devices in homes
that are to be demolished. In other homes, contact the gas company so that they
will be aware of the presence of the mercury device and remove it properly when
the meter needs to be replaced.
Safe Disposal:
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Mercury is often found in the plumbing at dentists offices in the form of amalgam, a compound containing about 50% mercury, which is used in dental fillings. Other buildings such as schools, hospitals and laboratories should also be inspected for mercury in the drain pipes. Below are some tips for inspecting drainage pipes.
Hospitals have experience with cleaning mercury out of pipes and traps. Detailed
information about appropriate procedures is available in an Infrastructure Report
by Beth Israel Hospital to the Massachusetts Water Resources Authority and the
Medical Academic and Scientific Community Organization (MASCO), available on
the web at http://www.masco.org/mercury/infra/pp.html
This report is also summarized in the Hospitals for a Healthy Environment's
Mercury Virtual Elimination Model Plan, Appendix L, available at http://www.h2e-online.org/mercury.asp.
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Description:
Fever thermometers for home and medical use, laboratory thermometers, and industrial
thermometers.
How to Identify:
Most industrial thermometers contain mercury. The bulbs of thermometers containing
mercury are usually silver in color. Types of mercury thermometers include:
Amount of Mercury:
Typical fever thermometers contain about 0.5 grams of mercury each, while larger
laboratory thermometers contain up to 3 grams of mercury. Industrial thermometers
can be even larger.
Safe Handling:
Mercury thermometers are easily broken when not handled carefully.
If a break occurs, use two pieces of paper or two razor blades to scoop it up
from a smooth surface. An eyedropper can also be used. Mercury spill kits are
available from safety equipment supply companies for larger mercury spills.
Safe Disposal:
Homeowners can use local household hazardous waste collection programs
for disposal, if available. For businesses:
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Name: Description:
3M Brand Tartan Track, or Flooring installed during the early 1970s contained
a mercury catalyst and was installed in gymnasiums during the 1970s. Other rubber
tracks or sports surfaces used in gyms may have contained mercury as well.
Safe Disposal:
The mercury content of this flooring varies, as does the amount of
degradation that has occurred over time, and therefore the extent to which mercury
can be leached from the flooring. In some cases, this flooring must be treated
as hazardous waste because it will fail the Resource Conservation and Recovery
Act Toxicity Characteristic Leaching Procedure. The 3M Corporation recommends
that even if the flooring is not characterized as a hazardous waste, that it
be disposed of in a landfill that is lined to prevent leaching rather than in
just any hazardous landfill. 3M will not provide assistance in removal or disposal,
but can provide a list of vendors that can remove the flooring, and dispose
of it properly. To obtain assistance, send approximately 5 pounds of track surface
cut into 1 pound or smaller pieces to:
Description:How to Identify:
A mercury float switch is usually present and visible in the septic tank.
Alternative Devices:
Alternatives to mercury float control switches include magnetic dry reed switches,
optic sensors, or mechanical switches. Most new float switches are made without
mercury.
How to Locate the Device:
The mercury is usually located in the bulb of the float. The float consists
of a hollow cylinder or sphere with an integral mercury or microswitch.
Safe Disposal:
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