Background Information on Mercury Sources and Regulations

I. Introduction

Mercury enters our lives more frequently than we may imagine. It may be in the fluorescent lights in our office, in old cans of latex paint, in our batteries, in our dental fillings, and numerous other sources. Within the United States alone, manufacturers use 500 - 600 metric tons of mercury annually as part of their manufacturing processes or to create products that rely on mercury's diverse properties.

A naturally-occurring, inorganic element, mercury's value in numerous industrial processes was discovered centuries ago. In very small quantities, it conducts electricity, measures temperature and pressure, acts as a biocide, and functions a catalyst. Over time, however, we have discovered that mercury is a potent neurotoxin, capable of impairing neurological development in fetuses and young children and damaging the central nervous system of adults. Mercury does not degrade and is not destroyed by combustion. When released to the environment, even in small quantities, it bioaccumulates, reaching dangerous levels in fish at the top of the aquatic food chain. Fish consumption advisories throughout Great Lakes waterbodies are testament to the health risks caused by mercury present in the Great Lakes ecosystem. Thirty-seven states have issued fish consumption advisories due to mercury contamination.

Scientists believe that atmospheric deposition contributes a large portion of the mercury found in the lakes and soil. Mercury emitted into the air by combustion, incineration, or manufacturing processes may later be deposited in lakes. Mercury emissions also come from natural sources including marine and aquatic environments, as well as volcanic and geothermal activity. However, recent studies suggest that anthropogenic sources contribute the majority of mercury releases.

Table 1: Overview

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At both federal and state levels, numerous efforts are underway to curtail mercury releases into the environment. To understand what options are available to reduce mercury use and release we must first answer four basic questions:

1. What are the sources of the mercury (supplying mercury and releasing mercury) into the environment?
2. What products contain mercury?
3. What regulations and non-regulatory measures currently influence mercury use and release?

The objective of this background information is to provide a context for understanding the full range of mercury sources and existing regulations that affect mercury use and release. From this information, we will be able to understand the extent to which existing regulations encourage a reduction in mercury use and release, and identify other opportunities--including regulatory and non-regulatory programs--that might hasten the pace of reductions.

Table 1 provides an overview of the material covered in this background section.

II. What are the sources of mercury?

Mercury is released into the environment from natural and anthropogenic sources. This report focuses on anthropogenic sources of mercury. Because mercury use is widespread throughout multiple industries as a process or product ingredient, its releases cannot be traced to one industrial sector. As a naturally occurring metallic element, mercury is also present as a trace contaminant in ores and fuels. It may be released into the environment when raw materials containing mercury are heated, even though the mercury itself plays no role in these processes. Thus, mercury releases occur as a result of decisions to intentionally use mercury in consumer products or manufacturing processes, and as a result of incidental releases.

Through a separate analysis, EPA is estimating the relative air emissions of different mercury sources. In the "Mercury Study," mandated by the Clean Air Act amendments of 1990 (§112(n)(1)(B); see discussion in Section III of this report), anthropogenic mercury sources are divided into the following broad groups, based on their emission properties: (1) combustion point sources; (2) manufacturing point sources; (3) miscellaneous point sources; and (4) area sources. Note that the individual source categories in the mercury study are similar to the ones used in this report.

Using emissions factors to estimate mercury releases, preliminary analysis indicates that, in the United States, anthropogenic sources emit 263 tons of mercury annually to the atmosphere. Of this total, combustion point sources, which include utility, commercial, industrial and other boilers, as well as municipal waste combustors and other incinerators, account for 85% of anthropogenic mercury emissions. Four specific combustion source categories account for the majority of anthropogenic emissions: municipal and medical waste incineration (25% each); utility boilers (21%); and commercial/industrial boilers (12%). In addition, manufacturing sources, which include chlor-alkali production, smelting, secondary mercury production, equipment manufacture, and other processes, account for 12% of total anthropogenic mercury emissions.

For the Virtual Elimination project, we have divided mercury sources into two broad groups, based on these two different roles of mercury: is mercury intentionally used or is it incidentally released? Table 2A shows the categories of mercury sources used in this report.

Table 2A: Categories of Mercury Sources

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Intentional Use: When mercury is used intentionally as an input in production processes or consumer products, three distinct but inter-related types of sources contribute to mercury releases. Sources in this category include:

1. Produce or supply mercury;
2. Use mercury as an input to manufacture products containing mercury or as part of a manufacturing process; and
3. Receive mercury-containing wastes for disposal.

All of these sources supply, use, or release intentionally used mercury into the environment. Because the quantity of mercury used in the manufacturing sector directly influences a significant amount of the mercury ultimately released into the environment, several leverage points are potentially available to reduce mercury releases. The price and supply of mercury, the feasibility of recycling, the availability of alternative inputs or processes, and the structure of existing regulations all contribute to a company's decision to use mercury in their production processes or products.

Incidental Release: Incidentally released mercury comes from two categories of sources:

1. Manufacturing processes where the raw materials contain trace amounts of mercury; and
2. Energy Production where the fuel source (primarily coal) contains mercury.

These sources, particularly coal combustion, and copper, lead and zinc smelting, may contribute a large portion of overall mercury air emissions. However, because their processes or products do not rely on mercury, their mercury emissions are not influenced by the costs associated with using mercury. They are affected only by regulatory costs associated with releasing mercury. Therefore, the menu of opportunities for reducing mercury releases from these sources will differ from sources that rely on mercury for some aspect of their business.

The source categories used throughout this report are, for the most part, consistent with sources identified in recently released reports that track mercury use and emissions, specifically the Bureau of Mines Mineral Industry Surveys, and the EPA Mercury Study Report to Congress mandated under the Clean Air Act Amendments of 1990 (§112(n)(1)(B)) (in preparation). By using similar source categories, we can combine information on mercury use and emissions trends at a national level with an overview of existing regulations. Table 2B lists the specific source categories of mercury that are covered in this analysis.

Table 2B: Sources of Mercury

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For this analysis, we have focused only on the largest uses and releases of mercury. Part D of this section discusses the reporting data available to track mercury sources. Data on mercury releases available through different reporting programs illustrates the industrial sectors where mercury release occurs most frequently in the Great Lakes states (based on the reporting requirements of each program). Because mercury has thousands of applications, these data may cover a much broader list of sources than the categories covered in this report. Appendix A includes a detailed "use tree" of mercury sources.

A. Intentional Use

This section provides a brief overview of the three source categories that contribute to mercury releases as a result of intentional mercury use: 1) production; 2) use; and 3) disposal.

1) Producing or Supplying Mercury

The mercury available for use in the United States comes from five main sources: (1) Primary mercury production; (2) Secondary mercury production (mercury recovery); (3) Mercury compound production; (4) Government stocks; and (5) Imports. Table 3 (and the accompanying figure) illustrates the relative contributions of these sources to the United States mercury supply.

1. Primary Mercury Production. Virgin mercury is mined from mercury ore or produced as a by-product of gold mining. In the United States, mercury is produced only as a by-product of gold mining. The last mercury ore mine, the McDermitt Mine in Nevada, closed in 1990. No by-product mercury mines are located in the Great Lakes States.

2. Secondary Mercury Production. Mercury is also recovered from discarded products and wastes such as chlor-alkali wastes, dental amalgams, fluorescent light tubes, electronic devices, and others. The mercury is vaporized in a retort and collected by condensation. Condensed mercury is then distilled to remove impurities. Triple-distilling yields the highest purity mercury. Secondary production almost doubled in 1993, expanding to 63% of U.S. total mercury consumption from 30% in 1991. The table below shows the trends in U.S. mercury consumption and secondary mercury production.

Three facilities, all located in Great Lakes states, produce the bulk of secondary mercury in the United States. D.F. Goldsmith Chemical and Metal in (Evanston, IL) specializes in distilling 99% or greater flowable mercury, and Bethlehem Apparatus (Hellertown, PA) and Mercury Refining Company (Albany, NY) retort and distill a wide variety of mercury wastes and scrap material. However, they do not accept certain types of RCRA wastes. At the end of 1993, eleven plants in the U.S. recycled mercury from fluorescent lights, using physical separation to recover mercury. Six of these facilities opened in 1993.

3. Mercury Compound Production. Mercury compounds are used in a wide variety of pharmaceutical and other uses. Commonly used mercury compounds include mercuric oxide (cathode material in batteries), mercuric chloride (pharmaceuticals), phenylmercuric acetate (used in paints and pharmaceuticals), mercuric sulfide (used in red pigment and other pharmaceuticals), and thimerosal (contact lens solution). Several mercury compound manufacturers are located in Great Lakes states:

4. Government Stocks. The United States government maintains a supply of mercury as part of the National Defense Stockpile, established at the end of World War I to maintain adequate supplies of materials deemed critical to national defense. The Defense Logistics Agency (DLA), a unit of the Department of Defense, manages the stockpile. DLA periodically evaluates the quantity of mercury and other materials needed in the stockpile, and may sell any "excess" material on the open market. Mercury is stored and sold in flasks, which contain 34.5 kg of mercury. Regulations governing the sale of excess mercury are described in Section III ("Regulations").

At the end of April 1994, DLA held 127,000 flasks (4,381 metric tons) of mercury in the stockpile. With a current stockpile goal of zero for mercury, all of this material is considered excess. DLA suspended stockpile mercury sales in January after selling its entire 1994 mercury allocation (10,000 flasks). However, DLA received Congressional approval to increase the total amount of mercury available for sale in fiscal year 1994 to 50,000 flasks (1,725 metric tons), leaving 40,000 flasks (1,380 metric tons) available to sell by September 30, the end of the fiscal year. For comparison, DLA sold only 8,250 of the 10,000 (345 metric tons) flasks authorized for sale during fiscal year 1993. In July 1994, however, DLA suspended future mercury sales until the environmental implications of these sales are addressed.

In past years, DLA also sold mercury for the Department of Energy (DOE), at monthly auctions. DOE holds secondary mercury (scrap mercury) at its facility in Oak Ridge, TN, leftover from mercury accumulated by the Atomic Energy Commission (DOE's predecessor) for use in nuclear reactors. All of this mercury is also considered excess to government needs. DLA suspended these mercury sales in July 1993, and plans to continue the suspension through 1994 in order to concentrate on selling its own material.

5. Imports. The United States imported 92 metric tons of mercury in 1992, the most recent year for which data are available. Of this total, 70% (64 metric tons) came from Canada and 29% came from Germany. The remainder (one percent) came from Spain and the United Kingdom. Mercury compounds are also imported. Section III ("Regulations") discusses mercury imports and relevant tariffs in more detail.

2) Using Mercury as an Input

Mercury is used throughout the worldwide industrial base as a result of its diverse properties. In very small quantities, it conducts electricity, measures temperature and pressure, and forms alloys with almost all other metals. With these and other unique properties, mercury plays an important role as a process or product ingredient in several industrial sectors.

a) Industrial Categories

For this report we have used the industrial categories reflected in the Bureau of Mines Minerals Commodities Summaries to illustrate the quantities of mercury used in different industrial sectors. Table 4 shows the trends in domestic mercury use since 1988, and the relative amounts of mercury used in the following industrial categories:

• Chemical and Allied Products;
• Electrical and Electronic Uses; and
• Instruments and Related Products.

Mercury use in the United States has declined 63% since 1988, to 558 metric tons per year in 1993 from 1,503 metric tons in 1988. In many cases, manufacturers appear to be moving away from mercury except those uses for which mercury is currently considered essential. However, the rate of decline has slowed since 1990.

Public pressure has also driven manufacturers to seek alternatives to non-essential mercury in their products. For instance, recent public outcry against mercury switches contained in children's light-up sneakers caused the manufacturer to change to a non-mercury switch that accomplishes the same purpose. The manufacturer now provides a toll-free number for customers to request a postage-paid mailer and return the shoes for proper mercury disposal.

U.S. Mercury Supply and Demand Source: Bureau of Mines: Mineral Industry Surveys, July, 1994

Chemical and Allied Products:
Chemical and allied products are responsible for the largest quantity of mercury used in the United States. This is due to the fact that a single industrial process--chlorine and caustic soda manufacture--alone uses more mercury than any of the other industrial sectors that use mercury. One chlor-alkali process, known as the mercury-cell process, relies on a mercury cathode to produce hydrogen gas and caustic soda. Caustic soda produced from this process may contain mercury, which in turn may contaminate other products.

At a national level, the chlor-alkali industry is regulated more directly for mercury than any other industry, with national air emissions limits, water discharge limits, and waste disposal restrictions. Although most mercury-cell chlor-alkali plants in the United States have closed, two still exist in the Great Lakes. Fourteen facilities remain in the United States. The chlor-alkali facility in Wisconsin is the second largest source of mercury emissions in that state.

Until the early 1990s, paint manufacturing used large quantities of mercury. The mercury compound phenylmercuric acetate was used as a biocide to control mildew in latex paints. However, EPA curtailed this use, eliminating mercury in interior latex paints in 1990 and exterior paints in 1991. Mercury emissions from volatized paint and demolition waste may continue from paints manufactured before the ban.

Electric and Electronic Uses:
In the electrical industry, mercury is used in electric lighting devices such as fluorescent lamps, wiring devices and switches, and several different kinds of batteries. In 1992, electrical manufacturing accounted for approximately 25% of the mercury used in the United States. As recently as 1988, battery manufacturing alone consumed almost 25% of the total mercury use in the United States. As manufacturers have found alternatives to mercury in alkaline batteries, and states began limiting mercury content in batteries, the volume of mercury used in batteries declined by over 95%. Mercury substitutes are not as readily available in fluorescent and other lamps. Mercury use in lamps appears to be rising especially as fluorescent lamps are promoted for energy conservation. Some manufacturers are developing fluorescent lamps that rely on smaller quantities of mercury.

Instruments and Related Products:
Mercury is also used in navigational devices, instruments that measure temperature and pressure, and other related uses. It is also used frequently in dental amalgam tooth fillings, although substitutes are available. Mercury use in this area has declined.

U.S. Consumption of Refined Mercury Metal, By Use (click for a larger image) Source: Bureau of Mines: Mineral Industry Surveys, July, 1994

b) Specific Uses of Mercury

In each of the industrial categories listed above, mercury plays a unique role in a manufacturing process or in a product. Table 5 lists the primary products that contain mercury in each of the source categories discussed in this section. These products, which may not pose mercury-related health risks during regular use, contribute mercury to the environment upon disposal. In addition, Appendix A includes a detailed mercury use tree.

Several states regulate mercury-containing products directly by limiting or prohibiting mercury content in certain products, and restricting disposal options. These regulations, which have had a direct impact on the quantity of mercury consumed in industrial activities, are discussed in more detail in Section III ("Regulations"). Many mercury products are used as components in widely used products. Mercury may be released when products are discarded. For example, Honeywell, Inc. a thermostat manufacturer, has developed a thermostat collection program in Minnesota to recycle the mercury switches.

Mercury is also used in numerous industrial processes for amalgamation, wood processing, as a solvent for reactive and precious metals, in nuclear reactors, and as a catalyst. Any facility that uses mercury in its process is a potential source of mercury emissions. Available reporting data may help locate and identify these sources. However, many sources that use or release mercury may fall below existing reporting thresholds.

3) Waste Disposal

Mercury-containing waste streams and products sent offsite for disposal contribute mercury to waste disposal facilities, which then release mercury into the environment. Industrial facilities, hospitals, and dental offices that divert their wastewater to Publicly Owned Treatment Works (POTWs) contribute to mercury in POTW effluent. Batteries, electric lamps, old paint, and other mercury-containing products contribute to the mercury emissions at municipal, hazardous waste, and medical waste incinerators, and may leach or vent mercury from landfills. As long as mercury is used in industrial processes, facilities will generate wastes that contain mercury, and consumer products will contribute mercury upon disposal. Table 6 shows the trends in mercury products contained in municipal solid waste.

Table 2B lists the different types of waste disposal sources. Appendix B provides details on the mercury-specific regulations for waste disposal sources. Note that cement kilns are not listed as a waste disposal source. However, cement kilns, used frequently as a waste disposal option, may burn hazardous wastes as a fuel source. Mercury may accumulate in the cement kiln dust. Metals emissions from cement kilns, which are regulated under EPA's interim standards for boilers and industrial furnaces (BIFs), are currently under review.

B. Incidental Release

1) Manufacturing Processes

As a natural element, mercury is found in many raw materials that form the backbone of the industrial base. Mercury is emitted from numerous manufacturing processes that use raw materials containing mercury as a trace element. A list of these sources is included in Table 2B, and Appendices A and B describe these sources in greater detail.

Smelting processes, such as copper, lead, and zinc smelting, may contribute a large percentage of overall mercury releases. For example, the Copper Range Smelter in White Pine, Michigan, releases over 1000 pounds of mercury annually. In 1992, Zinc Corporation of America contributed 90% of total mercury releases reported in Toxic Chemical Release Inventory (TRI) for the Great Lakes states. This high level of mercury release, which was sent off site for recycling, reflected periodic cleaning of the sulfuric acid plants, not ongoing releases. Mercury is also present in zinc concentrates and is removed as an impurity during sulfuric acid production.

Because these sources are not dependent on mercury as a component of their business, they are not influenced by the costs associated with using mercury. In some cases, they may be more amenable to control technology or to incentives that are not tied directly to mercury.

2) Energy Production

Utility boilers, particularly coal-fired utilities, may contribute a large portion of the overall atmospheric mercury emissions due to the presence of mercury in fuel sources. Although currently unregulated for mercury emissions, they are the subject of intensive study under a separate Utility Study mandated by the 1990 Clean Air Act amendments (§112(n)(1)(A)). The report, scheduled for completion in 1995, is evaluating the extent to which coal combustion contributes to overall mercury releases, as well as the need for specific mercury emissions regulations for the utility industry. Given this in-depth report on the full range of utility emissions, we will not focus on utility mercury emissions in this report, beyond identifying any relevant existing regulations.

C. Data Sources for the Great Lakes States

Mercury releases are reported under several different federal and state programs, each with a different set of regulatory requirements, and each covering a different subset of the regulated community. Mercury information is available from three federal reporting programs: (1) the Toxic Chemical Release Inventory (TRI), (2) RCRA Biennial Report System (BRS) data, and (3) the Permit Compliance System (PCS) data for water releases. In addition to these federal reporting programs, some Great Lakes states maintain other reporting systems that provide additional information on mercury releases. Data is included for Wisconsin air point sources, Michigan's Critical Materials Wastewater Report, and Indiana's Aerometric Information Retrieval System (AIRS).

Information from each of these sources is summarized below, and included in detail in Appendix F. With the exception of TRI data, all information is shown by SIC code to illustrate the distribution of mercury releases across different industrial sectors. Appendix F1 provides a summary of the number of facilities that report mercury releases under each of these programs, and shows how the number of facilities varies by reporting program as a result of differing reporting requirements. For instance, 572 facilities in the Great Lakes states report mercury-bearing wastestreams under RCRA biennial reporting requirements, while only 14 facilities report mercury releases under TRI.

Toxic Chemical Release Inventory (TRI). Appendix F2 shows TRI mercury releases for the Great Lakes states. The Toxic Chemical Release Inventory contains chemical release and transfer information from manufacturing facilities (SIC codes 20 - 39) that meet reporting thresholds (manufacture or process 25,000 pounds of a listed chemical or otherwise use 10,000 pounds of a listed chemical. Appendix F2a includes 1992 data for the eight Great Lakes states, including any source reduction activities implemented by each facility. Appendix F2b contains similar data for the 1991 reporting year.

In 1992, 14 facilities in the Great Lakes States reported mercury releases, down from 20 facilities that reported in 1991. Tables 7A shows the trends in mercury releases from 1987 -1992, and Table 7B shows the industrial sectors that reported mercury releases in 1992. The majority of mercury releases reported in 1992 came from Zinc Corporation of America. Because zinc concentrates contain mercury that is released during the sulfuric acid production process, mercury builds up in the sulfuric acid plants. Periodically, these plants must be cleaned, which generates a higher then normal volume of waste for that year.

Appendices F2c and F2d show nationwide mercury releases reported in TRI for 1992 and 1991, respectively. Great Lakes states reported 60.65% of the mercury releases and transfers reported nationwide in TRI for 1992. This number was skewed by the large volume of waste generated by Zinc Corporation of America, as described above. In 1991, Great Lakes states reported 18.13% of total mercury releases and transfers nationwide.

RCRA Biennial Report data. Appendix F3 includes 1991 data from the RCRA Biennial Report System (BRS). BRS data tracks information on hazardous waste generated and managed by large quantity generators and permitted Treatment, Storage, and Disposal (TSD) facilities. RCRA wastes are identified by waste code, several of which indicate the presence of mercury in a wastestream or discarded product (see RCRA discussion in section III).

Appendix F3a shows the number of facilities, by SIC code, that report mercury-bearing wastestreams. The data reflects only recurrent waste generation, and does not include one-time waste or remediation wastes. A total of 572 facilities reported mercury-bearing wastestreams. Mercury-bearing wastestreams showed up most frequently in the following industrial sectors: colleges and universities (35 facilities), pharmaceutical preparations (28 facilities), electric services (22 facilities), plastics materials and resins (21 facilities), and industrial organic chemicals (20 facilities). Because most of the mercury-bearing wastes are characteristic for mercury (i.e., they exceed the regulatory concentration limit for mercury), and include other substances, it is difficult to gauge the quantity of mercury in the wastestreams.

Biennial report data also indicates the source processes that generated a given waste stream. Appendix F3b lists the sources processes in each SIC code that generated mercury-bearing waste streams. A summary table at the end of the appendix shows the frequency with which each process occurred. A total of 39 different sources processes contributed to mercury-bearing wastestreams. Laboratory wastes was reported most frequently (168 facilities), followed by discarded out of data products or chemicals (76 facilities).

PCS data. Appendix F4 contains data from EPA's Permit Compliance System (PCS) for water discharges. PCS data approximates point source loads from municipal and industrial dischargers. The information is based on monitoring data supplied by regulated facilities. EPA uses PCS data as the basis for its enforcement program. In 1993, the top 10 mercury dischargers in Region 5 were:

Wisconsin Air Point Source Emissions Data. Appendix F5 contains air emissions data for Wisconsin facilities (1992 data). As part of its Clean Air Act Title V Operating Permit Program, Wisconsin collected emissions data from facilities that reported releases greater than one pound of hazardous air pollutants, including mercury. Sixty one facilities reported mercury emissions under this program. This total includes 13 utilities and nine paper mills. A utility reported the largest emissions (1272 pounds), followed by a chlor-alkali facility (1071 pounds).

Michigan Critical Materials Registry. Appendix F6 includes data from Michigan's Critical Materials Wastewater Report (1991 data). As part of its water quality program, Michigan collects information on chemical use and release from facilities that use any substance, including mercury, on the "Critical Materials Registry." It is the only program that requires facilities to report information about chemical use. Under this program, "use" means the presence of the chemical on site. A total of 270 facilities reported mercury use, including 19 hospitals, 18 motor vehicle parts facilities, 16 plastics products facilities, and 16 utilities. The total mercury use was between 288,174 - 308,510 pounds. Of this total, 121 facilities reported discharges ranging in total between 271 and 1740 pounds. 160 facilities reported residuals ranging in total between 2720 and 10,420 pounds.

Indiana Aerometric Information Retrieval System (AIRS): Appendix F7 includes data from Indiana's 1991 AIRS database. Mercury emissions quantities in this database are estimates derived by the Indiana Department of Environmental Management, based on data reported for criteria pollutant emissions. As such, the quantities do not represent measured data, nor data supplied directly by individual facilities.

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