Introduction

This Fact Sheet summarizes the use of mercury-added components in cooking ranges and other cooking equipment based on data obtained only from the Interstate Mercury Education & Reduction Clearinghouse (IMERC)¹ Mercury-Added Products Database². It covers gas and electric cooking ranges manufactured for both residential and commercial use. The residential ranges are used in both homes and in recreational vehicles.

Mercury Components in Cooking Ranges

Mercury-added components are used in three types of cooking ranges: gas, gas-electric, and electric. Gas ranges typically contain only one mercury-containing component, a flame sensor, or gas shut-off valve. Gas-electric and electric ranges contain fluorescent bulbs for backlighting; gas-electric ranges may also contain a flame switch, which acts like a flame sensor. Commercial electric ranges may also contain relays. Each of these components and the function of mercury in them are described below.

Flame sensors, also called automatic gas shut-off valves, are used as safety devices in gas ranges and other appliances. A flame sensor stops the flow of gas if the open flame does not produce heat, such as when the pilot light is out or the product is malfunctioning. Mercury is contained within the bulb of the sensor, and the heat of the pilot light vaporizes and expands this mercury, causing the gas valve to open. Note that today's household gas-electric ranges do not require a flame sensor because electrical current controls the pilot light; however, electric ignition gas ranges may also contain a flame switch which acts like a flame sensor to shut off gas to the oven when the power is off.

Fluorescent bulbs provide back lighting for control panels. Mercury in the bulb vaporizes, producing ultraviolet energy that passes through phosphor coatings to produce visible light.

A relay is an electrically controlled device that allows electrical current flowing through one circuit to switch current on and off in a second circuit. Relays are often used to switch large current loads by supplying relatively small currents to a control circuit. There are two general families of relays: electro-mechanical and semiconductor.

Mercury displacement relays are one type of electro-mechanical relay; they use metallic plunger devices containing magnetic shells or sleeves to displace mercury. When power is off, the mercury level is below the electrode tip of the plunger and no current path exists between the insulated center electrode and the mercury pool. When power is applied, the pull of the magnetic field draws the plunger down into the mercury pool and the plunger centers itself within the current path. When power is shut off, the buoyancy force of the mercury causes the plunger, which is lighter than the mercury, to resume its original position. The mercury level then drops, breaking the current path through the center electrode and mercury pool.

Amount of Mercury Used in Cooking Equipment

Table 1 presents the amount of mercury in each of the three components that are used in gas, gas-electric, and electric ranges, as reported in the Mercury-Added Products Database. The number of manufacturers refers to the number of manufacturers of ranges, or range components, reporting a particular amount of mercury. Note that the amount of mercury in fluorescent lamps, relays, and thermostats is provided only for the flame sensors, fluorescent lamps, and relays that are used in cooking ranges.

A number of important caveats must be considered when reviewing the data summarized in this fact sheet:

• The information does not represent the entire universe of cooking ranges containing mercury-added components, and therefore underestimates the total amount of mercury reported for this category of products. IMERC continues to receive product notification forms and reviews these filings prior to adding the data to the database.
• The data presented summarizes mercury-added components in ranges sold nationwide in the U.S. in calendar year 2001. It does not include products that were manufactured prior to January 1, 2001.
• Summing the total amounts of mercury across product categories may result in double counting the same mercury. The same mercury component may be reported on by the original equipment manufacturer, the manufacturer that purchases that component and incorporates it into a larger product, and a distributor that makes that product available for sale in one of the IMERC states.
• Reported data only includes mercury that is used in the product, and does not include mercury emitted during the mining and/or manufacturing.

Table 1: Amount of Mercury in Individual Components in Cooking Ranges
Mercury-added Component	Amount of Mercury (milligrams)	Number of Components in Each Range	Number of Manufacturers
Flame sensor	> 1,000	1	8
Fluorescent lamps	> 5 - 10 > 10 - 50	1 1	1 3
Relay	> 1,000	1	1

Total Amount of Mercury in Mercury-Added Components Used in Cooking Ranges

Table 2 presents the total amount of mercury in cooking ranges sold in the U.S. during calendar year 2001 for the three types of ranges and the names of the manufacturers reporting their use of mercury-added components in these appliances.

TABLE 2: Total Mercury in Cooking Ranges Sold in the US, Calendar Year 2001
Product/Component	Total Mercury in Products Sold, Calendar Year 2001 (pounds)	Manufacturers Reporting
Gas ranges with flame sensors	1,311.21	Blodgett Corporation, Maytag Appliance, GE Appliances, Whirlpool Corporation, Gunkol Gunes, Electrolux, Brown Stove Works, & Peerless Premier Appliance Co.
Gas-electric range with fluorescent bulbs	11.95	Maytag Appliance, GE Appliances, Electrolux, & Whirlpool
Commercial electric ranges with relays	6328.26	Blodgett Corporation
Total for all ranges:                   7,651.42

The total amount of mercury in the flame sensor components sold in the U.S. during calendar year 2001 is presented in Table 3. Gas range manufacturers reported selling 1,311.21 pounds of mercury as flame sensors in their cooking ranges in the US in 2001, while the manufacturers of flame sensors reported selling 2,829.08 pounds of mercury. It is important to note that this is simply presented here as a ballpark comparison because some oven manufacturers did not provide data on the total amount of mercury sold in the U.S. in their products, and instead referred to the original equipment manufacturer of the mercury-added component for the information. For example, one gas range manufacturer did not provide total data on mercury sold in its products and referred the IMERC states back to the manufacturer of the flame sensor for this information. Other possible explanations include:

• mercury flame sensors are used in products other than gas ranges, and/or
• a number of manufacturers of gas ranges have not yet filed Notification Forms, and/or
• US manufacturers of gas cooking ranges purchased more flame sensors in calendar year 2001 than they needed to make the units that they sold that year.

TABLE 3: Total Mercury in Gas Shut-Off Valves Sold in the US, Calendar Year 2001
Component	Total Mercury in Products Sold, Calendar Year 2001 (pounds)	Manufacturers Reporting
Flame switch	35.82	Harper-Wyman
Flame sensor	2,793.26	Harper-Wyman
Total for all shut-off valves:         2,829.08

Total Amount of Mercury in Mercury-Added Components Used in Other Cooking Equipment

Table 4 presents the total amount of mercury in other types of cooking equipment sold in the U.S. during calendar year 2001.

TABLE 4: Other Mercury "Cooking" Equipment
Component	Total Mercury in Products Sold, Calendar Year 2001 (pounds)	Manufacturers Reporting
Commercial frialator with relay	274.4	Pitco Frialator Inc.
Commercial gas griddle with flame sensor	39.5	Vulcan Hart/ITW, Wolf Range Company
Hot Plate holder with relay	98.0	Carrier Commercial Refrigeration
Rethermalizer and hot plate holder with relay	112.2	Carrier Commercial Refrigeration
Total for all other mercury cooking equipment:         524.1

The states participating in IMERC are continuously receiving Notification Forms from mercury-added product manufacturers, possibly including those that produce mercury flame sensors and cooking ranges, and the data presented in this Fact Sheet probably underestimate the amount of mercury sold in these products.

²The Mercury-added Products Database contains information on the amount and purpose of mercury in products submitted by, or on behalf of, product manufacturers in compliance with laws in the states of Connecticut, Maine, New Hampshire, and Rhode Island. Beginning in 2001, these states required companies manufacturing, distributing, or importing mercury-added products to report certain information on these products. The information is reviewed and approved by an IMERC Notification Committee comprised of representatives from each participating state. The online Mercury-added Product Database and the Notification Forms and Instructions can be found at the following URL: http://www.newmoa.org/prevention/mercury/imerc/notification/

Published in September 2004