Mercury is present in many consumer products that become part of the solid waste stream. The report, Trends in Mercury Use in Products: Summary of Interstate Mercury Education & Reduction Clearinghouse (IMERC) Mercury-Added Products Database summarizes the IMERC data for these products. They include, but are not limited to, the following mercury-added products and components:

• Thermometers
• Thermostats
• Fluorescent and other lamps (including CFLs)
• Manometers
• Switches
• Relays
• Button-cell batteries
• Dental amalgam
• Chemicals and Formulated Products

The Interstate Mercury and Education Reduction Clearinghouse (IMERC) Mercury-Added Products Database presents information submitted by or on behalf of mercury-added product manufacturers to the IMERC-member states on the amount and purpose of mercury in consumer products. The database is intended to inform consumers, companies, recyclers, policy makers, and others about: products that contain intentionally-added mercury, the amount of mercury in a specific product, the amount of mercury in a specific product line sold in the U.S. in a given year, and manufacturers of mercury-added products.

The following is a brief list of some of the mercury-containing products that are still being manufactured and/or sold in the U.S. Mercury-free alternatives are available for many of these products.

Wiring Devices - Switches, Relays, & Thermostats
This is currently the category of mercury-added products that consumes the largest amount of mercury. The category includes individual switches as well as switch components that are built into larger products, such as cooking equipment, home appliances, and pumps.

• Switches - Mercury switches are products or devices that open or close an electrical circuit, or a liquid or gas valve. They include float switches, actuated by a change in liquid levels; tilt switches, actuated by a change in the switch position; pressure switches, actuated by a change in pressure; and temperature switches actuated by a change in temperature. They are used in a variety of consumer, commercial, and industrial products, including appliances, space heaters, ovens, air handling units, security systems, leveling devices, and pumps. The amount of mercury used in individual switches varies widely. Depending on the type of switch and their function, they contain anywhere from less than 1 gram to up to 70 grams of mercury.

• Relays - Mercury relays are products or devices that open or close electrical contacts to control the operation of other devices in the same or another electrical circuit. Mercury-added relays include mercury displacement relays, mercury wetted reed relays, and mercury contact relays. They are used in telecommunication circuit boards, commercial or industrial electric ranges, and other cooking equipment. The amount of mercury used in individual relays ranges from less than 1 gram to more than 150 grams. Relay units, devices that contain multiple relays per "unit" may contain up to 400 grams of mercury.

  See additional information in the IMERC Fact Sheet: Mercury Use in Switches and Relays.

• Flame Sensors - Automatic gas shut-off valves, also known as flame sensors, are used as safety devices in stand-alone gas ranges. Mercury is contained within the bulb of the sensor, and is used to regulate the flow of gas in the oven. Flame sensors generally contain greater than one gram of mercury. However, many states have started to restrict or prohibit the use of mercury flame sensors in ovens and other cooking equipment and there are now non-mercury alternatives available.

  See additional information in the IMERC Fact Sheet: Mercury Use in Cooking Equipment.

• Thermostats - Mercury thermostats use mercury switches to sense and control room temperature through communication with heating, ventilating, and air conditioning (HVAC) equipment. According to the Thermostat Recycling Corporation (TRC), mercury thermostats contain an average of 1.4 mercury switches with approximately 2.8 grams of elemental mercury per switch. Alternative non-mercury electronic thermostats are widely available.

  See additional information in the IMERC Fact Sheet: Mercury Use in Thermostats and in the Mercury-Thermostats Topic Hub.

Electric Lighting
Mercury is used in a variety of light bulbs, including fluorescent lamps, high-intensity discharge (HID) lamps, and neon signs. Mercury-based lighting, particularly fluorescent light bulbs are relatively energy-efficient in comparison with incandescent lamps.

• Fluorescent lighting - Depending on the type of fluorescent lamp, they can contain a wide range of mercury, from greater than 0 up to 100 milligrams (mg). The typical types of fluorescent lamps include: linear (straight), U-tube (bent), and circline (circular) fluorescent lamps/tubes; bug zappers; tanning lamps; black lights; germicidal lamps; high output lamps; cold-cathode fluorescent lamps; and compact fluorescent lamps (CFLs).

• CFLs - Compact fluorescent lamps (CFLs) use the same basic technology as linear fluorescent lamps, but are folded or spiraled in order to approximate the physical volume of an incandescent bulb. Individual CFLs generally contain less than 10 mg of mercury, with a significant portion (over two-thirds) containing less than 5 mg of mercury.

• HID lighting - High intensity discharge (HID) is the term commonly used for several types of lamps, including metal halide, high pressure sodium, and mercury vapor lamps. Depending on the type of HID lamp, they can contain 5 mg to over 1,000 mg of mercury.

• Neon lighting - Neon lights are gas discharge bulbs that commonly contain neon, krypton, and argon gasses (also called noble gasses) at low pressure, which are combined to form different colors. Neon lights are estimated to contain approximately 250 to 600 mg of mercury per bulb, depending on the size, shape, and color of the neon bulb or sign. Red neon lights do not contain mercury.

See additional information about the types of mercury-added lamps and the amounts of mercury that they contain in the IMERC Fact Sheet: Mercury Use in Lighting.

Also, the Maine Department of Environmental Protection (Maine DEP) completed the Maine Fluorescent Lamp Study Final Report in 2001, which estimates the total mercury content in certain types of fluorescent lamps: www.state.me.us/dep/rwm/mercury/lampreport/lampstudy.htm.

Measuring Devices & Control Instruments
As the only metal that is liquid at room temperature, mercury expands and contracts evenly with temperature and pressure changes. These characteristics have made mercury useful in devices used for measuring temperature and pressure, including thermometers, barometers, and sphygmomanometers (blood pressure cuffs).

Mercury fever, laboratory, and industrial thermometers help to measure temperature as the mercury inside the glass rises and falls with the temperature.

• Fever thermometers - Mercury fever thermometers contain approximately 0.5 - 1 gram of mercury. There are many types of alternative non-mercury fever thermometers on the market, including a variety of small digital thermometers and others.

• Laboratory thermometers - The average mercury laboratory thermometers contains three grams of mercury; long or over-sized lab thermometers may contain up to five grams of mercury. A variety of non-mercury thermometers are available for laboratory use including certain alcohol, spirit-filled, and digital thermometers.

  See additional information in the Mercury-Thermometers Topic Hub.

• Barometers - A barometer is a device that measures atmospheric pressure. Mercury barometers contain approximately 500 grams of mercury each. Non-mercury digital replacements and mineral spirit barometers are readily available.

• Manometers - Manometers are used to measure the pressure difference in liquids and gases and are frequently used to measure air pressure within air ducts or compressed air lines. Dairy manometers may contain approximately 350 grams of mercury, which is usually contained in a U-shaped tube that has one end open to the atmosphere. Sphygmomanometers are a specific type of mercury manometer used for measuring blood pressure. Sphygmomanometers contain approximately 110 grams of mercury. There are a variety of non-mercury alternatives available, including digital and aneroid.

See additional information in the IMERC Fact Sheet: Mercury Use in Measuring Devices.

Dental Supplies
The most common use of mercury in dental operations is dental amalgam. Dental amalgam is a filling material used in restoring teeth. It is an alloy that contains silver, tin, copper, other metallic elements, and mercury, which typically makes up about 50 percent. The total amount of mercury per amalgam capsule can range from less than 100 mg to greater than 1,000 mg of mercury depending on the size of the amalgam. Non-mercury resin and composite materials are alternatives for mercury dental amalgam.

See additional information in the IMERC Fact Sheet: Mercury Use in Dental Amalgam and in the Mercury-Dental Topic Hub.

Batteries
There are a variety of button-cell batteries that contain mercury, including zinc air, silver oxide, and alkaline manganese oxide batteries. Mercuric oxide button-cell batteries are no longer sold in the U.S.; however, larger mercuric oxide batteries may still be used in limited applications, such as hospitals and military facilities. Other batteries, such as AAA, AA, C, and D alkaline; atomic; and lithium-ion batteries, do not contain mercury.

Zinc air, silver oxide, and alkaline manganese oxide batteries, including those used in hearing aids, wristwatches, toys, and small and portable electronic devices, contain mercury. These batteries contain between 5 and 25 mg of mercury each. There are now non-mercury alternatives available for some of these button-cell batteries. In addition, U.S. battery manufacturers have voluntarily committed to eliminating mercury in button-cell batteries by 2011.

See additional information in the IMERC Fact Sheet: Mercury Use in Batteries.

Laboratory and Pharmaceutical Chemicals, Paints, and Pesticides
Mercury can be an active ingredient, a preservative, or a contaminant introduced in the manufacture of one of the ingredients in a chemical formulation. Examples of mercury compounds used in clinical laboratories include Zenker's solution, B5 solution, certain hematoxylin solutions, and thimerosal. Mercury compounds (e.g., mercuric chloride, mercuric nitrate, and others) were used as fungicides and biocides, in pesticides manufactured prior to 1995, and indoor and exterior paint manufactured prior to 1991.

See additional information in the IMERC Fact Sheet: Formulated Mercury-Added Products.

Other
Numerous mercury-containing products in today's waste stream are no longer produced, including cylindrical alkaline batteries, certain pesticides, and certain latex paints made before the early 1990s. These and other "legacy products" are mercury-added products that are no longer sold as new in commerce, but may still be in use, may be resold as a used or antique product, or may be stored in homes or businesses. For more information about mercury-added legacy products, visit the Mercury Legacy Product website.

Source: NEWMOA/IMERC, "Trends in Mercury Use in Products: Summary of the Interstate Mercury Education and Reduction Clearinghouse (IMERC) Mercury-Added Products Database," June 2008. http://www.newmoa.org/prevention/mercury/imerc/factsheets/mercuryinproducts.pdf {PDF]

Last Updated: 11/14/08