# National Emission Standards for Hazardous Air Pollutants for Iron and Steel Foundries > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A02-31234 ## Record - **Collection:** Federal Register - **Document type:** Proposed Rule - **Published:** December 23, 2002 - **Citation:** 67 FR 78274 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 [OAR-2002-0034; FRL-7416-4] RIN 2060-AE43 National Emission Standards for Hazardous Air Pollutants for Iron and Steel Foundries AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: This action proposes national emission standards for hazardous air pollutants (NESHAP) for iron and steel foundries. The EPA has identified iron and steel foundries as a major source of hazardous air pollutant (HAP) emissions. These proposed standards will implement section 112(d) of the Clean Air Act (CAA) by requiring all major sources to meet HAP emissions standards reflecting application of the maximum achievable control technology (MACT). The HAP emitted by facilities in the iron and steel foundries source category include metal and organic compounds. For iron and steel foundries that produce low alloy metal castings, metal HAP emitted are primarily lead and manganese with smaller amounts of cadmium, chromium, and nickel. For iron and steel foundries that produce high alloy metal or stainless steel castings, metal HAP emissions of chromium and nickel can be significant. Organic HAP emissions include acetophenone, benzene, cumene, dibenzofurans, dioxins, formaldehyde, methanol, naphthalene, phenol, pyrene, toluene, triethylamine, and xylene. Exposure to these substances has been demonstrated to cause adverse health effects, including cancer and chronic or acute disorders of the respiratory, reproductive, and central nervous systems. The proposed NESHAP would reduce nationwide HAP emissions from iron and steel foundries by over 900 tons per year (tpy). DATES: Comments. Submit comments on or before February 21, 2003. Public Hearing. If anyone contacts the EPA requesting to speak at a public hearing by January 13, 2003, a public hearing will be held on January 22, 2003. ADDRESSES: Comments. Comments may be submitted electronically, by mail, by facsimile, or through hand delivery/courier. Follow the detailed instructions as provided in the SUPPLEMENTARY INFORMATION section. Public Hearing. If a public hearing is held, it will be held at the new EPA facility complex in Research Triangle Park, NC at 10 a.m. Persons interested in attending the hearing or wishing to present oral testimony should notify Cassie Posey, Metals Group (MD-C439-02), U.S. EPA, Research Triangle Park, NC 27711, telephone (919) 541-0069, at least 2 days in advance of the hearing. FOR FURTHER INFORMATION CONTACT: Kevin Cavender, Metals Group, (MD-C439-02), Emission Standards Division, Office of Air Quality Planning and Standards, U.S. EPA, Research Triangle Park, NC 27711, telephone number (919) 541-2364, electronic mail (e-mail) address, cavender.kevin@epa.gov. SUPPLEMENTARY INFORMATION: Regulated Entities. Categories and entities potentially regulated by this action include: Category NAICS code* Examples of regulated entities Industry 331511 Iron foundries. Iron and steel plants. Automotive and large equipment manufacturers. 331512 Steel Investment Foundries 331513 Steel foundries (except investment). Federal government Not affected. State/local/tribal government Not affected. *North American Information Classification System. This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. To determine whether your facility is regulated by this action, you should examine the applicability criteria in § 63.7682 of the proposed rule. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT section. Docket. The EPA has established an official public docket for this action under Docket ID No. OAR-2002-0034. The official public docket is the collection of materials that is available for public viewing in the Iron and Steel Foundries NESHAP Docket at the EPA Docket Center (Air Docket), EPA West, Room B-108, 1301 Constitution Avenue, NW., Washington, DC 20004. The Docket Center is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742. Electronic Access. An electronic version of the public docket is available through EPA's electronic public docket and comment system, EPA Dockets. You may use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public comments, access the index of the contents of the official public docket, and access those documents in the public docket that are available electronically. Once in the system, select “search” and key in the appropriate docket identification number. Certain types of information will not be placed in the EPA dockets. Information claimed as confidential business information (CBI) and other information whose disclosure is restricted by statute, which is not included in the official public docket, will not be available for public viewing in EPA's electronic public docket. The EPA's policy is that copyrighted material will not be placed in EPA's electronic public docket but will be available only in printed, paper form in the official public docket. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the EPA Docket Center. For public commenters, it is important to note that EPA's policy is that public comments, whether submitted electronically or in paper, will be made available for public viewing in EPA's electronic public docket as EPA receives them and without change unless the comment contains copyrighted material, CBI, or other information whose disclosure is restricted by statute. When EPA identifies a comment containing copyrighted material, EPA will provide a reference to that material in the version of the comment that is placed in EPA's electronic public docket. The entire printed comment, including the copyrighted material, will be available in the public docket. Public comments submitted on computer disks that are mailed or delivered to the docket will be transferred to EPA's electronic public docket. Public comments that are mailed or delivered to the docket will be scanned and placed in EPA's electronic public docket. Where practical, physical objects will be photographed, and the photograph will be placed in EPA's electronic public docket along with a brief description written by the docket staff. Comments. You may submit comments electronically, by mail, by facsimile, or through hand delivery/courier. To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your comment. Please ensure that your comments are submitted within the specified comment period. Comments submitted after the close of the comment period will be marked “late.” The EPA is not required to consider these late comments. Electronically. If you submit an electronic comment as prescribed below, EPA recommends that you include your name, mailing address, and an e-mail address or other contact information in the body of your comment. Also include this contact information on the outside of any disk or CD ROM you submit and in any cover letter accompanying the disk or CD ROM. This ensures that you can be identified as the submitter of the comment and allows EPA to contact you in case EPA cannot read your comment due to technical difficulties or needs further information on the substance of your comment. The EPA's policy is that EPA will not edit your comment and any identifying or contact information provided in the body of a comment will be included as part of the comment that is placed in the official public docket and made available in EPA's electronic public docket. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Your use of EPA's electronic public docket to submit comments to EPA electronically is EPA's preferred method for receiving comments. Go directly to EPA Dockets at http://www.epa.gov/edocket, and follow the online instructions for submitting comments. Once in the system, select “search” and key in Docket ID No. OAR-2002-0034. The system is an “anonymous access” system, which means EPA will not know your identity, e-mail address, or other contact information unless you provide it in the body of your comment. Comments may be sent by electronic mail (e-mail) to air-and-r-docket@epa.gov, Attention Docket ID No. OAR-2002-0034. In contrast to EPA's electronic public docket, EPA's e-mail system is not an “anonymous access” system. If you send an e-mail comment directly to the docket without going through EPA's electronic public docket, EPA's e-mail system automatically captures your e-mail address. E-mail addresses that are automatically captured by EPA's e-mail system are included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket. You may submit comments on a disk or CD ROM that you mail to the mailing address identified in this document. These electronic submissions will be accepted in WordPerfect or ASCII file format. Avoid the use of special characters and any form of encryption. By Mail. Send your comments (in duplicate, if possible) to: Iron and Steel Foundries NESHAP Docket, EPA Docket Center (Air Docket), U.S. EPA West, (MD-6102T), Room B-108, 1200 Pennsylvania Avenue, NW., Washington, DC 20460, Attention Docket ID No. OAR-2002-0034. By Hand Delivery or Courier. Deliver your comments (in duplicate, if possible) to: EPA Docket Center, Room B-108, U.S. EPA West, 1301 Constitution Avenue, NW., Washington, DC 20004, Attention Docket ID No. OAR-2002-0034. Such deliveries are only accepted during the Docket Center's normal hours of operation. By Facsimile. Fax your comments to: (202) 566-1741, Attention Iron and Steel Foundries NESHAP Docket, Docket ID No. OAR-2002-0034. CBI. Do not submit information that you consider to be CBI through EPA's electronic public docket or by e-mail. Send or deliver information identified as CBI only to the following address: Roberto Morales, OAQPS Document Control Officer (C404-02), U.S. EPA, 109 TW Alexander Drive, Research Triangle Park, NC 27709, Attention Docket ID No. OAR-2002-0034. You may claim information that you submit to EPA as CBI by marking any part or all of that information as CBI (if you submit CBI on disk or CD ROM, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is CBI). Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2. Worldwide Web (WWW). In addition to being available in the docket, an electronic copy of today's proposed rule is also available on the WWW through the Technology Transfer Network (TTN). Following the Administrator's signature, a copy of the proposed rule will be placed on the TTN's policy and guidance page for newly proposed or promulgated rules at http://www.epa.gov/ttn/oarpg. The TTN provides information and technology exchange in various areas of air pollution control. If more information regarding the TTN is needed, call the TTN HELP line at (919) 541-5384. Outline. The information presented in this preamble is organized as follows: I. Background A. What Is the Statutory Authority for NESHAP? B. What Criteria Are Used in the Development of NESHAP? C. What Processes Are Used at Iron and Steel Foundries? D. What HAP are Emitted and how are they Controlled? E. What Are the Health Effects Associated With Emissions From Iron and Steel Foundries? II. Summary of the Proposed Rule A. What Are the Affected Sources? B. What Are the Proposed Emissions Limitations? C. What Are the Proposed Work Practice Standards? D. What Are the Proposed Operation and Maintenance Requirements? E. What Are the Proposed Requirements for Demonstrating Initial and Continuous Compliance? F. What Are the Proposed Notification, Recordkeeping, and Reporting Requirements? G. What Are the Proposed Compliance Deadlines? III. Rationale for Selecting the Proposed Standards A. How Did We Select the Affected Sources? B. What Other Emissions Sources Did We Consider? C. How Did We Select the Pollutants? D. How Did We Determine the Basis and Level of the Proposed Standards for Emissions Sources in the Metal Casting Department? E. How Did We Determine the Basis and Level of the Proposed Standards for Emissions Sources in the Mold and Core Making Department? F. How Did We Select the Proposed Initial Compliance Requirements? G. How Did We Select the Proposed Continuous Compliance Requirements? H. How Did We Select the Proposed Notification, Recordkeeping, and Reporting Requirements? IV. Summary of Environmental, Energy, and Economic Impacts A. What Are the Air Quality Impacts? B. What Aare the Cost Impacts? C. What Are the Economic Impacts? D. What Are the Non-air Health, Environmental, and Energy Impacts? V. Solicitation of Comments and Public Participation VI. Statutory and Executive Order Reviews A. Executive Order 12866, Regulatory Planning and Review B. Paperwork Reduction Act C. Regulatory Flexibility Act (RFA), as Amended by the Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. et seq. D. Unfunded Mandates Reform Act of 1995 E. Executive Order 13132, Federalism F. Executive Order 13175, Consultation and Coordination with Indian Tribal Governments G. Executive Order 13045, Protection of Children from Environmental Health Risks and Safety Risks H. Executive Order 13211, Actions that Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer Advancement Act I. Background A. What Is the Statutory Authority for NESHAP? Section 112 of the CAA requires the EPA to establish technology-based regulations for all categories and subcategories of major sources emitting one or more of the HAP listed in section 112(b). Major sources are those that emit or have the potential to emit at least 10 tpy of any single HAP or 25 tpy of any combination of HAP. The EPA may later develop additional standards under section 112(f) to address residual risk that may remain even after application of the technology-based controls. Area sources are stationary sources of HAP that are not major sources. The regulation of area sources is discretionary. If there is a finding of a threat of adverse effects on human health or the environment, then the source category can be added to the list of area sources to be regulated. Section 112(c) of the CAA requires us to list all categories of major and area sources of HAP for which we would develop national emissions standards. We published the initial list of source categories on July 16, 1992 (57 FR 31576). “Iron Foundries” and “Steel Foundries” were two of the source categories on the initial list. The 1992 listing of these source category is based on our determination that iron foundries and steel foundries may reasonably be anticipated to emit one or more HAP listed in section 112(b) in quantities sufficient to be major sources. We combined these two categories into one category, “Iron and Steel Foundries.” We believe this is reasonable because of the similarities in processes, emissions, and controls. Also, several foundries pour both iron and steel. This proposed rule will apply to each new and existing iron and steel foundry. Approximately 650 iron and steel foundries exist in the U.S. Of these, about 100 iron and steel foundries are anticipated to be major sources of HAP. Most of these major sources are foundries that are operated by manufacturers of automobiles and large industrial equipment and by suppliers of these manufacturers. B. What Criteria Are Used in the Development of NESHAP? Section 112 of the CAA requires that we establish NESHAP for the control of HAP from both new and existing major sources. The CAA requires the NESHAP to reflect the maximum degree of reduction in emissions of HAP that is achievable. This level of control is commonly referred to as the maximum achievable control technology (MACT). The MACT floor is the minimum control level allowed for NESHAP and is defined under section 112(d)(3) of the CAA. In essence, the MACT floor ensures that the standard is set at a level that assures that all major sources achieve the level of control at least as stringent as that already achieved by the better-controlled and lower-emitting sources in each source category or subcategory. For new sources, the MACT floor cannot be less stringent than the emissions control that is achieved in practice by the best controlled similar source. The MACT standards for existing sources can be less stringent than standards for new sources, but they cannot be less stringent than the average emissions limitation achieved by the best-performing 12 percent of existing sources in the category of subcategory (or the best performing 5 sources for categories or subcategories with fewer than 30 sources). In developing MACT, we also consider control options that are more stringent than the floor. We may establish standards more stringent than the floor based on the consideration of cost of achieving the emissions reductions, any health and environmental impacts, and energy requirements. C. What Processes Are Used at Iron and Steel Foundries? Iron and steel foundries manufacture castings by pouring molten iron or steel melted in a furnace into a mold of a desired shape. The primary processing units of interest at iron and steel foundries because of their potential to generate HAP emissions are: metal melting furnaces; scrap preheaters; pouring areas; pouring, cooling, and shakeout lines; mold and core making lines; and mold and core coating lines. Metal Melting Furnaces There are three types of furnaces used to melt scrap metal at iron and steel foundries: cupolas, electric arc furnaces, and electric induction furnaces. Cupolas are used exclusively to produce molten iron; electric arc furnaces and electric induction furnaces are used to produce either molten iron or molten steel. Cupolas. A cupola is vertical cylindrical shaft furnace that uses coke and forms of iron and steel, such as scrap and foundry returns, as the primary charge components. The iron and steel are melted through combustion of the coke by a forced upward flow of heated air. Cupolas are equipped with afterburners downstream from the charge to incinerate carbon monoxide (CO), which is a major byproduct of coke combustion. Some of the coke used to fuel the cupola also becomes part of the molten metal, thereby raising the carbon content of the molten metal. Consequently, cupolas are used to produce iron castings; steel castings must have carbon content of less than 1 percent, which cannot be achieved in a cupola. There are, generally, two distinct cupola design configurations. The differences between the two designs relate to the method of charging. In one configuration, termed above charge gas takeoff, charging is done through a door in the shaft above the level of the charge. Alternatively, in the below charge gas takeoff configuration, the flow of gas is taken from an opening in the side of the shaft below the level of the charge. The latter configuration is more typical of modern cupolas. In either case, the offgas may be directed through a heat exchanger to transfer heat to the inlet air for energy conservation. Molten metal, along with slag, is tapped from an opening in the bottom of the furnace shaft much like a blast furnace. Tapping is essentially a continuous process, whereas charging is done in batches. Electric induction furnaces and scrap preheaters. An electric induction furnace is a vessel in which forms of iron and steel, such as scrap and foundry returns, are melted through resistance heating by an electric current that is induced in the metal by passing an alternating current through a coil surrounding the metal charge or surrounding a pool of molten metal at the bottom of the vessel. An electric induction furnace operates in batch mode, an operating cycle consisting of charging, melting the charge, adding an additional charge (backcharging) in some cases and melting that charge, and tapping the molten metal. Scrap feed for an electric induction furnace is commonly preheated, usually by direct exposure to a gas flame, prior to charging to the furnace. Preheating is done primarily to eliminate volatile substances such as water and residual oil and grease that may vaporize suddenly and cause an explosion if added to a molten charge or heel in the furnace. When preheating is done, the scrap is commonly heated to 800§ F or higher because the cost of initial heating with gas is less costly than heating with electricity. A scrap preheater, where used, is considered to be an integral part of the electric induction furnace melting operation. Electric arc furnaces. An electric arc furnace is a vessel in which forms of iron and steel, such as scrap and foundry returns, are melted through resistance heating by an electric current that flows through the arcs formed between electrodes and the surface of the metal and also through the metal between the arc paths. Typically, the electric arc furnace is equipped with a removable cover and charged from the top. Molten metal is tapped from the electric arc furnace by removing the cover and tilting the furnace. An electric arc furnace operates in batch mode as does an electric induction furnace, an operating cycle consisting of charging, melting, backcharging in some cases and melting that charge, and tapping. Pouring, Cooling, and Shakeout Lines A pouring, cooling, and shakeout line includes three major operations: pouring molten metal into molds, allowing the metal to cool and solidify, and removing the castings from the molds. The most common type of pouring, cooling, and shakeout line is the conveyor or pallet line, in which the pouring ladle is stationary and molds are moved to the ladle by conveyor or rail. After pouring is complete, the molds move along the conveyor or rail through a cooling area, which is often an enclosed tunnel. A less common type of pouring, cooling, and shakeout line is floor or pit pouring, which is used by small to medium sized foundries that do not have sufficient capital to finance mechanization and also by foundries that produce castings too large to be transported by conveyor. In this type of line, molds are placed on an open floor or in a pit, and the pouring ladle is transported to the molds, generally by overhead pulley. After pouring, the casting is cooled in place. After castings have solidified, they are removed from the sand molds in a process called shakeout. At most foundries, shakeout is a mechanized process where molds are placed on vibrating grids or conveyors to shake the sand loose from the casting. In some foundries, the castings and molds are separated manually. Mold and Core Making Lines Most iron and steel foundries pour metal into molds that are made primarily of sand. Molds may also be made of tempered metal (iron or steel) that are filled by gravity (permanent molds) or by centrifugal force (centrifugal casting). Some systems use polystyrene or other low density plastic (foam) patterns and pack sand around the patterns. This type of casting operation is referred to as expendable pattern casting, or the lost foam process since the plastic pattern is volatilized (and/or pyrolyzed) by the molten metal as the castings are poured. The outer shape of a casting is determined by the shape of the molds. Molds are typically made in two halves that are subsequently joined together. The inner shapes of the casting that cannot be directly configured into the mold halves are created by inserting separately made components called cores, which are almost universally made of sand. Sand cores are often required in sand molds as well as in many permanent mold and centrifugal casting operations. Most sand molds are made from green sand, which is a mixture of approximately 85 to 95 percent sand, 4 to 10 percent bentonite clay, 2 to 5 percent water, and 2 to 10 percent carbonaceous materials such as powdered coal (commonly called sea coal), petroleum products, cereals, and starches. The composition of green sand is chosen so that the sand will form a stable shape when compacted under pressure, maintain that shape when heated by the molten metal poured, and separate easily from the solidified metal casting. The clay and water bind the sand together. The carbonaceous materials partially volatilize when molten metal is poured into the mold, creating a reducing atmosphere that prevents the surface of the casting from oxidizing while it solidifies. Some sand molds and most sand cores are bound into shape by plastic-or resin-like chemical substances. Chemical binder systems are used when the shape of the mold or core cannot be made from green sand or when strength and dimensional stability requirements are too stringent for green sand to provide. Chemically bonded molds and cores are made by first blending the sand and chemicals (mixing), then forming the sand into the desired shape and hardening (curing) the chemical binder to fix the shape. Chemical binder systems are of three types depending on the curing process required: • Chemicals that cure upon heating (thermosetting), • Combinations of chemicals that cure by reacting with each other at ambient temperature (self-setting or nobake), and • Chemicals that react by catalysis upon exposure to a gas at ambient temperature (gas-cured or cold box). Several systems of each type are available, with the choice of system depending on such features as strength of the mold or core, speed of curing, and shelf life. Mold and Core Coating Lines Molds and cores are often coated with a finely ground refractory material to provide a smoother surface finish on the casting. We refer to these processes as “coating” operations. The refractory material is applied as a slurry. After coating, the liquid component of the slurry is either allowed to evaporate or, if it is a flammable substance such as alcohol, eliminated by ignition (the light-off process). D. What HAP Are Emitted and How Are They Controlled? Metal Melting Furnace Emissions Almost all emissions from a cupola are contained in the flow of air exiting the stack of the furnace, which contains particulate matter (PM) and organic compounds in addition to CO. The HAP in PM emissions from cupolas are primarily lead and manganese, with other HAP such as cadmium, chromium, and nickel present in lesser amounts. These HAP originate as impurities or trace elements in the scrap metal fed to the furnace. Organic HAP arise as by-products from combustion of coke and also from incomplete combustion of residual oil and grease on the scrap. Cupola exhaust gases contain acetophenone, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and pyrene. Most cupolas control PM emissions by dedicated baghouses or wet scrubbers. Also, most cupolas employ afterburners, which effectively destroy organic HAP. Another potential source of emissions is the charging door of a cupola in which the gas takeoff is above the charge. However, the cupola is generally operated with enough vacuum in the shaft to prevent gases from exiting the door during normal operations. Emissions of PM from electric induction furnaces contain HAP metals such as manganese and lead, but may also contain significant amounts of chromium or nickel if stainless steel or nickel alloy castings are produced. Emissions from scrap preheaters contain PM and organic species that have not been characterized. Emissions from electric induction furnaces and scrap preheaters are controlled by baghouses, cyclones, and wet scrubbers, with emissions from both types of units often controlled by the same device. Organic emissions from scrap preheaters are typically controlled by direct flame heating of the scrap and, at one source, by afterburning the preheater emissions. Emissions of PM from electric arc furnaces contain HAP metals such as lead and manganese, but may also contain significant amounts of chromium or nickel if stainless steel or nickel alloy castings are produced. Emissions may also include trace levels of organic substances that have not been characterized. Emissions of PM are typically controlled by baghouses. Organic emissions are controlled by natural incineration within the furnace. Pouring, Cooling, and Shakeout Line Emissions The majority of HAP emissions from pouring, cooling, and shakeout lines are organic HAP created by incomplete combustion of organic material in the mold and core sand. When molten metal comes into contact with organic materials in the sand such as binder chemicals and sea coal, these materials are partially volatilized and incinerated. Due to the limited availability of oxygen in the poured molds, combustion is incomplete, and the mold offgas can contain a wide variety of organic substances. The primary HAP emitted are benzene, formaldehyde, and toluene. The offgases from most molds ignite spontaneously. For floor and pit pouring, the offgas does not always spontaneously flare but is ignited by applying a flame to the mold's vent locations. Aside from lighting-off mold vents, three foundries use add-on controls to further reduce organic emissions from pouring, cooling, and shakeout lines. In addition to organic emissions, pouring lines are a source of metal HAP emissions. Metal HAP contained in the molten metal is emitted as metal fumes when the metal is poured into the molds. Baghouses and scrubbers are used to control metal HAP emissions at several pouring lines. Mold and Core Making and Mold and Core Coating Line Emissions Mold making using green sand produces virtually no emissions. The use of chemical binder systems, by contrast, can produce significant HAP emissions. In the process of mixing, forming, and curing, volatile constituents of these chemicals evaporate to some extent. Many binder system components contain HAP as polymerization reactants, solvents, or catalysts. Although some information on the composition of binder system components is proprietary, much is known about their HAP content. The HAP used in these chemicals and emitted in the mold and core making process include cumene, formaldehyde, methanol, naphthalene, phenol, and xylene. Also, triethylamine is commonly used as a catalyst gas in the cold box process. Most foundries capture and control triethylamine emissions with wet scrubbers that use acid solution as the collection medium. No other organic emissions from mold and core making lines are controlled. Emissions of HAP can also arise in the process of coating the molds and cores. The liquid component of the slurry may contain a HAP such as methanol. Coating emissions are controlled only where the light-off process is used to eliminate flammable constituents. E. What are the Health Effects Associated With Emissions From Iron and Steel Foundries? The metal HAP emitted from melting furnaces includes cadmium, chromium, lead, manganese, and nickel. Aromatic organic HAP produced by mold and core making lines; melting furnaces; and pouring, cooling, and shakeout lines contain acetophenone, benzene, cumene, dibenzofurans, dioxins, naphthalene, phenol, pyrene, toluene, and xylene. The non-aromatic organic HAP emitted are formaldehyde, methanol, and triethylamine. The known health effects of these substances are described in the “EPA Health Effects Notebook for Hazardous Air Pollutants-Draft,” EPA-452/D-95-00, PB95-503579 (December 1994), which is available on-line at: http://www.epa.gov/ttn/uatw/hapindex.html. Although numerous HAP may be emitted from iron and steel foundries, only a few account for essentially all of the mass of HAP emissions from these foundries. These HAP are: formaldehyde, methanol, napthalene, triethylamine, manganese, and lead. Of the HAP listed above, benzene is a known human carcinogen of moderate carcinogenic hazard. Cadmium, 2,3,7,8-TCDD (dioxin), formaldehyde, lead, and nickel are classified as probable carcinogens. Chromium can exist in two valence states. Chromium VI is a known human carcinogen of high carcinogenic hazard by inhalation. ( Note: Chromium III and Chromium VI by oral pathways are classified as Group D “not classifiable as to carcinogenicity in humans.”) Acute effects of some of the HAP listed above include irritation to the eyes, nose, and throat, nausea, vomiting, drowsiness, dizziness, central nervous system depression, and unconsciousness. Chronic effects include respiratory effects (such as coughing, asthma, chronic bronchitis, chest wheezing, respiratory distress, altered pulmonary function, and pulmonary lesions), gastrointestinal irritation, liver injury, and muscular effects. Reproductive effects include menstrual disorders, reduced incidence of pregnancy, decreased fertility, impotence, sterility, reduced fetal body weights, growth retardation, slowed postnatal neurobehavioral development, and spontaneous abortions. The proposed rule would reduce emissions of many of these HAP and would also reduce PM emissions, which are regulated under national ambient air quality standards. Emissions of PM have been associated with aggravation of existing respiratory and cardiovascular disease and increased risk of premature death. We have no data to assess to what extent iron and steel foundries emissions are causing health effects. We recognize that the degree of adverse effects to health experienced by exposed individuals can range from mild to severe. The extent and degree to which the health effects may be experienced depends on: • Pollutant-specific characteristics ( e.g. , toxicity, half-life in the environment, bioaccumulation, and persistence); • The ambient concentrations observed in the area ( e.g. , as influenced by emissions rates, meteorological conditions, and terrain); • The frequency and duration of exposures; and • Characteristics of exposed individuals ( e.g. , genetics, age, pre-existing health conditions, and lifestyle), which vary significantly with the population. II. Summary of the Proposed Rule A. What Are the Affected Sources? The affected sources are each new or existing metal casting department, and each new or existing mold and core making department, at an iron and steel foundry that is a major source of HAP emissions. A new affected source is one for which construction or reconstruction begins after December 23, 2002. An existing affected source is one for which construction or reconstruction began on or before December 23, 2002. The emissions sources in a metal casting department covered by the proposed rule include metal melting furnaces, scrap preheaters, pouring stations at an existing metal casting department, pouring areas and pouring stations at a new metal casting department, and pouring, cooling, and shakeout lines. The emissions sources in a mold and core making department covered by the proposed rule include each mold and core making and mold and core coating line. B. What Are the Proposed Emissions Limitations? The proposed rule includes emissions limits for metal and organic HAP as well as operating limits for capture systems and control devices. Particulate matter, CO, and volatile organic compounds (VOC) serve as surrogate measures of HAP emissions. Today's proposed rule includes the following emissions standards: • Each melting furnace and scrap preheater at an existing metal casting department must control emissions of PM to 0.005 grains per dry standard cubic foot (gr/dscf), and each melting furnace and scrap preheater at a new metal casting department must control emissions of PM to 0.001 gr/dscf. • Each cupola at a new or existing metal casting department must control CO emissions to 200 parts per million by volume (ppmv). • Each scrap preheater at a new or existing metal casting department must achieve a 98 percent reduction, by weight, in VOC emissions or an outlet concentration of no more than 20 ppmv of VOC (as propane). • Each pouring station at an existing metal casting department must control emissions of PM to 0.010 gr/dscf, and each pouring station or pouring area at a new metal casting department must control emissions of PM to 0.002 gr/dscf. • Each new metal casting department must achieve a 98 percent reduction, by weight, in VOC emissions or an outlet concentration of no more than 20 ppmv of VOC (as propane). This limit would be a flow-weighted average. • Each triethylamine cold box mold and core making line at a new or existing mold and core making department must control triethylamine emissions to 1 ppmv. The owner or operator of an affected source would be required to install a capture and collection system for each emissions source subject to an emissions limit. The capture and collection system would be required to maintain a 200 foot per minute (fpm) face velocity when all access doors (if present) are in the open position. In addition, for each capture and collection system installed on an affected source, the owner and operator would be required to establish operating limits for capture systems parameter (or parameters) appropriate for assessing capture system performance. At minimum, the limits must indicate the level of the ventilation draft and damper position settings. The proposed rule would require the owner or operator to operate each capture system at or above the lowest value or settings established in the operation and maintenance (O&M) plan. Proposed operating limits for control devices are: • If a baghouse is applied to PM emissions from a metal melting furnace, scrap preheater, or shakeout station, the alarm on the bag leak detection system must not sound for more than 5 percent of the total operating time in a semiannual reporting period. • If a wet scrubber is applied to PM emissions from a pouring station, the 3-hour average pressure drop and scrubber water flowrate must remain at or above the minimum levels established during the initial performance test. • If a wet acid scrubber is applied to triethylamine emissions from a cold box mold and core making line, the 3-hour average scrubbing liquid flowrate must remain at or above the minimum level established during the initial performance test, and the 3-hour average pH of the scrubber blowdown must remain at or below the maximum level so established. If a combustion device is applied to triethylamine emissions from a cold box mold and core making line, the 3-hour average combustion zone temperature must remain at or above the minimum level established during the initial performance test. The proposed operating limits would not apply to a combustion device applied to organic HAP emissions from a cupola, scrap preheater, or pouring, cooling, and shakeout line because continuous emissions monitoring systems (CEMS) would be required to directly measure CO and VOC emissions. C. What Are the Proposed Work Practice Standards? To reduce HAP emissions from metal casting departments, facilities would be required to develop and operate according to written specifications and procedures for the selection and inspection of the scrap iron or steel that limit the amount of organics and HAP metals in the scrap used as furnace charge. For a pouring, cooling, and shakeout line in an existing metal casting department and a pouring area in a new or existing metal casting department, foundries would be required to manually ignite gases from mold vents that do not automatically ignite. Four work practice standards are proposed for coating and binder chemicalformulations used at new or existing mold and core making departments: • All mold and core making lines would be required to use non-HAP coating formulations. • All furan warm box mold and core making lines would be required to use methanol-free binder chemical formulations. • All phenolic urethane cold box or phenolic urethane nobake mold and core making lines would be required to use naphthalene-depleted solvents. Depletion of naphthalene can not be accomplished by substituting other HAP for the naphthalene. • All other types of mold and core making lines (not furan warm box, phenolic urethane cold box, or phenolic urethane nobake) would be required to use reduced-HAP binder formulations unless it is technically and/or economically infeasible. Foundries would conduct an initial study to evaluate and identify alternatives. A foundry that does not adopt reduced-HAP binder formulations must repeat the study and submit a report every 5 years to demonstrate that all applicable alternatives remain technically or economically infeasible. D. What Are the Proposed Operation and Maintenance Requirements? The proposed rule would ensure good O&M of control equipment by requiring all foundries to prepare and follow a written O&M plan for capture systems and control devices. The O&M plan must include capture system operating limits, requirements for capture system inspections and repairs, procedures and schedules for preventative maintenance of control devices, and corrective action steps to be taken in the event of a bag leak detection system alarm. The proposed rule also includes requirements for a startup, shutdown, and malfunction plan similar to those required for other MACT rules. See § 63.6(e)(3) of the NESHAP General Provisions (40 CFR part 63, subpart A) for more information on these requirements. E. What Are the Proposed Requirements for Demonstrating Initial and Continuous Compliance? Emissions Limitations The proposed rule includes requirements for foundries to conduct performance tests for all emissions sources subject to an emissions limit to show they meet the applicable limit. The proposal would require foundries to measure the concentration of PM using EPA Methods 1 through 4, and either Method 5, 5B, 5D, 5F, or 5I, as applicable, in 40 CFR part 60, appendix A. The proposed rule would require foundries to use Method 18 in 40 CFR part 60, appendix A, to determine the concentration of triethylamine. The proposed rule would also require foundries using CO or VOC CEMS to demonstrate compliance by conducting CEMS performance evaluations and measuring emissions for 3 consecutive operating hours. The proposed rule also includes procedures for establishing operating limits for capture systems and control devices, and revising the limits, if necessary or desired, after the initial performance test. To demonstrate continuous compliance, the proposed rule would require a CO CEMS for cupolas, a VOC CEMS for scrap preheaters, and a VOC CEMS for pouring, cooling, and shakeout lines at a new metal casting department. The proposed rule would require performance tests every 5 years to demonstrate continuous compliance with the emissions limits. The proposed rule would require emissions sources not equipped with a CEMS to conduct repeat performance tests every 5 years. Monitoring of capture system and control device operating parameters would demonstrate continuous compliance with the operating limits between emissions tests. These proposed monitoring requirements include bag leak detection systems for baghouses and continuous parameter monitoring systems (CPMS) for capture systems (unless damper positions are fixed), wet scrubbers, combustion devices, and wet acid scrubbers. Technical specifications, along with requirements for installation, operation, and maintenance of these monitoring systems, are included in the proposed rule. Records would be required to document any bag leak detection system alarms and to show conformance with inspection and maintenance requirements for baghouses, CPMS, and CEMS. Work Practice Standards No performance test would be required to demonstrate initial compliance with the work practice standards. Foundries would certify in their notification of compliance status that they have installed any required capture systems, submitted the required written plans, and that they will meet each of the applicable work practice requirements in the plan or rule as proposed. Records for visual inspections of all incoming shipments are required to show continuous compliance with the work practice standards for scrap selection and inspection plans. Daily visual inspections are required to show continuous compliance with the work practice standard for mold vent ignition. A record must be kept of each inspection. To demonstrate continuous compliance with the work practice standards for coatings and binder chemicals, foundries would keep records of the chemical composition of the formulations. A new compliance certification would be required each time they change the formulation. F. What Are the Proposed Notification, Recordkeeping, and Reporting Requirements? These requirements rely on the NESHAP General Provisions in 40 CFR part 63, subpart A. Table 1 to subpart EEEEE (the proposed rule) shows each of the requirements in the General Provisions (§§ 63.2 through 63.15) and whether they apply. The major notifications include one-time notifications of applicability (due within 120 days of promulgation), performance tests (due at least 60 days before each test), performance evaluations, and compliance status. The notification of compliance status is required within 60 days of the compliance demonstration if a performance test is required or within 30 days if no performance test is required. Foundries would be required to maintain records that are needed to document compliance, such as performance test results; copies of the startup, shutdown, and malfunction plan; O&M plan; scrap selection and inspection plan, and associated corrective action records; monitoring data; and inspection records. In most cases, records must be kept for 5 years, with records for the most recent 2 years kept onsite. However, the O&M plan; scrap selection and inspection plan; and startup, shutdown, and malfunction plan would be kept onsite and available for inspection for the life of the affected source (or until the affected source is no longer subject to the proposed rule requirements.) All foundries would make semiannual compliance reports of any deviation from an emissions limitation (including an operating limit), work practice standard, or O&M requirement. If no deviation occurred and no monitoring systems were out of control, only a summary report would be required. More detailed information is required in the report if a deviation did occur. An immediate report would be required if actions taken during a startup, shutdown, or malfunction were not consistent with the startup, shutdown, and malfunction plan. G. What Are the Proposed Compliance Deadlines? Foundries with existing affected sources would be required to comply within 3 years of publication of the final rule. New or reconstructed sources that start up on or before the promulgation date for the final rule would have to comply by the promulgation date. New or reconstructed sources that start up after the promulgation date must comply upon initial startup. III. Rationale for Selecting the Proposed Standards A. How Did We Select the Affected Sources? Affected source means the collection of equipment, activities, or both within a single contiguous area and under common control that is included in the source category or subcategory to which the emissions limitations, work practice standards, and other regulatory requirements apply. The affected source may be the entire collection of equipment and processes in the source category or it may be a subset of equipment and processes. For each rule, we must decide which individual pieces of equipment and processes warrant separate standards in the context of the CAA section 112 requirements and the industry operating practices. We considered three different approaches for designating the affected source: the entire iron and steel foundry, groups of emissions points, and individual emissions points. We did not designate the entire foundry as the affected source because this broad approach would require us to establish a facilitywide MACT floor based on the total HAP emissions indicative of best-performing foundries. Applying a single MACT floor to groups of process and fugitive emissions points would be impracticable given the diversity of processes used at individual foundries, especially considering the variety of mold and core making processes used. One significant group of emissions points in an iron and steel foundry is the metal casting department, which includes emissions from metal melting furnaces (cupolas, electric induction furnaces, scrap preheaters, and electric arc furnaces) and pouring, cooling, and shakeout lines (where molten metal is poured into molds, molds are cooled, and castings are separated from molds). Although some variation exists in these operations at different foundries, these variations do not significantly alter the nature or amount of the HAP emissions from the individual emissions sources, the types of HAP emitted, or the control technology typically used to reduce HAP emissions. We, therefore, concluded that identifying the group of major processes in the metal casting department at an iron and steel foundry as an affected source is appropriate. The other significant group of emissions points at iron and steel foundries is associated with mold and core making operations. The primary source of HAP emissions from these processes is HAP constituents in binder and coating chemicals. All major source foundries make extensive use of chemical systems to bind the mold and core sand, and certain types of binder systems have much higher volatile HAP content than other systems, so that the amounts of HAP and the specific HAP constituents emitted from mold and core making operations vary substantially between foundries processing the same amount of sand and having similar metal production rates. The use and formulations of mold and core coatings also varies significantly between foundries. Because of the extreme variation in potential to produce HAP emissions, it is necessary to consider mold and core making and coating operations separately from other foundry processes in determining emissions standards. This subset of equipment and processes is termed the mold and core making department. In selecting the affected sources for regulation, we identified the HAP-emitting operations, the HAP emitted, and the quantity of HAP emissions from the individual or groups of emissions points. The proposed rule includes emissions limits or standards for the control of emissions from melting furnaces and pouring, cooling, and shakeout lines at metal casting departments, and mold and core making lines at mold and core making departments. Selection of these units as the emissions sources represents the most effective means for EPA to regulate emissions from this source category and addresses all of the principal emissions points from units in this source category. B. What Other Emissions Sources Did We Consider? As described in the background information document, there are numerous other ancillary emissions sources that may contain trace quantities of HAP. The emissions sources that would be regulated under this proposed rule generally contribute over 99 percent of a foundry's HAP emissions. Coatings applied to the cast parts may also significantly contribute to a foundry's total HAP emissions. The HAP emissions from these emissions sources will be regulated under the proposed NESHAP for Coating of Miscellaneous Metal Parts and Products (67 FR 52779). Sand handling systems are used to recover sand from the shakeout system, avoid buildup at facility work stations, and to reuse sand for making new molds. This sand may include trace organic chemicals such as pyrolysis products formed during pouring and cooling that condensed on the cooler sand at the outer circumference of the mold. Due to the large diameter of the PM emissions generated during sand handling and the fact that these sources are located inside facility buildings, we do not expect that these emissions are released from the foundry building or property line as ambient emissions. Therefore, we have not proposed standards regulating sand handling systems. Mechanical finishing operations, such as cut-off, grinding, and shot blasting, also produce PM emissions. These PM emissions may contain significant concentrations of metal HAP. However, as with sand handling systems, we do not expect that the large diameter particles generated during these operations are released as ambient emissions. Therefore, we have not proposed standards regulating mechanical finishing operations. Metal treatment is generally used to achieve the final chemistry needed in the cast part. It is also used to produce ductile iron by adding magnesium to the molten iron (commonly referred to as inoculation). Metal treatment generally occurs in holding furnaces or transfer ladles, but may occur in an electric induction furnace or electric arc furnace. The emissions from metal treatment operations consist primarily of magnesium, but may include trace amounts of metal HAP. It is unclear to what extent these emissions may be released from the building, but emissions estimates from the available data suggest that these emissions do not contribute appreciably to the emissions from the foundry. As such, we believe regulating metal treatment would not achieve any measurable reduction in metal HAP emissions. Therefore, we have not proposed standards regulating metal treatment at this time. Holding furnaces are often used to store the molten metal until it is needed by the foundry's pouring stations. These furnaces are almost completely enclosed and, consequently, they are not a source of ambient HAP emissions from foundries. Again, no measurable reduction in metal HAP emissions can be achieved by regulating holding furnaces. Therefore, we have not proposed emissions standards regulating holding furnaces. In addition to the operations listed above, we have not proposed emissions standards regulating metal HAP emissions from cooling lines and shakeout stations. Although these are significant sources of organic HAP emissions, they do not contribute to ambient emissions of metal HAP from iron and steel foundries. Cooling lines do not generate PM emissions and the molten metal is not exposed to the atmosphere where metal fumes might be released. Shakeout stations are a significant source of PM emissions, however, these emissions are almost entirely comprised of sand. As with sand handling systems, the PM (sand) emissions may include trace organic chemicals such as pyrolysis products formed during pouring and cooling that condensed on the cooler sand at the outer circumference of the mold. It may also include small chunks of metal. However, due to the large diameter of the PM emissions generated during shakeout, we do not expect that these emissions are released as ambient emissions from the foundry. Therefore, we are not proposing standards for metal HAP from cooling lines and shakeout stations. We are specifically considering whether to adopt a fugitive emissions standard in the form of a shop opacity limitation or a roof vent emissions limitation. Such a requirement would provide additional assurance that any fugitive emissions sources within the physical strictures at iron and steel foundries would not contribute significantly to ambient emissions from such facilities. Such a standard might include an opacity limit of 5 percent or a no visible emissions limit for all foundry building releases (roof vents, doors, or other openings) that are not otherwise covered by a specific emissions limit. If we were to establish such a requirement, we would establish the level for the limit by evaluating existing state and permit limits and any available emissions information consistent with the procedures described later in this document that was used to establish MACT for other emissions sources at iron and steel foundries. However, we have not proposed an opacity or visible emissions limit because our emissions estimates indicated that the emissions sources for which we have not proposed standards are unlikely to contribute to ambient HAP emissions from the iron and steel foundries. Thus, while we do not have conclusive data regarding the potential for fugitive emissions to contribute to ambient HAP emissions from foundries, it appears that the inclusion of an opacity or visible emissions limit for the foundry building might not function to control HAP emissions from the foundry. We specifically request comment on the regulatory options that we are considering for control of potential fugitive emissions from these miscellaneous sources. We request additional data on the potential for the miscellaneous sources discussed above to contribute to ambient HAP emissions from iron and steel foundries, including comments and supporting data that either demonstrates the need to regulate one or several of these currently unregulated emissions sources or that supports our position that these emissions sources do not release HAP to the atmosphere in quantities sufficient to require additional regulation. We also request comment on the appropriateness of the possible levels for the fugitive emissions limits discussed above, and the methodology for calculating such limits for this source category. C. How Did We Select the Pollutants? There are three types of melting furnaces used at major source iron and steel foundries: Cupolas, electric induction furnaces, and electric arc furnaces. All three furnace types emit PM that is known to contain HAP metals, predominately manganese and lead. We, therefore, decided to establish standards for metal HAP emissions. Source tests on cupolas have shown the presence of small amounts of organic HAP including acetophenone, polychlorinated dibenzofurans, polychlorinated dibenzo-p-dioxins, and pyrene. We concluded that establishing standards for these HAP is appropriate. We selected PM as a surrogate for metal HAP emissions from melting furnaces and CO as a surrogate for organic HAP emissions from cupolas. Pouring molten metal into sand molds produces emissions from the incomplete combustion of the organic chemicals used in chemically bonded molds and cores and also from sea coal and other organic constituents of green sand. These products of incomplete combustion are known to contain benzene, formaldehyde, and toluene. In addition, small amounts of HAP metals are emitted during pouring. We selected PM as a surrogate for metal HAP emissions from pouring and VOC as a surrogate for organic HAP emissions from pouring, cooling, and shakeout lines. In the process of mixing sand and binder chemicals, forming the sand into molds and cores, and curing the resulting shapes, volatile constituents of the binder chemicals evaporate to some extent. The HAP emitted in the mold and core making process include cumene, formaldehyde, methanol, naphthalene, phenol, triethylamine, and xylene. Emissions vary widely between different types and formulations of chemical systems; however, for each system the HAP species emitted can be identified. We, therefore, decided to establish standards to control the emissions of these HAP. The source of HAP emissions from the mold and core coating operation is the liquid component of the slurry, which may contain a HAP such as methanol. Alternative liquid formulations that contain no HAP are available. We conclude that substitution of coating material formulations is possible, and that it is feasible to establish emissions standards in this proposal based on pollution prevention that address liquid HAP used in coating operations. D. How Did We Determine the Basis and Level of the Proposed Standards for Emissions Sources in the Metal Casting Department? Scrap Selection There is the potential for HAP emissions to occur during all phases of metal casting (including melting, pouring, cooling, and shakeout) due to impurities (such as lead, paint, oil and grease) that may be present in the scrap metal. By reducing, to the extent possible, the amounts of these impurities in the scrap metal, foundries can achieve HAP emissions reductions throughout the metal casting department. In 1998, we conducted a detailed and comprehensive survey of known foundries in the U.S. From this survey, EPA compiled the data from the 595 iron and steel foundries that provided survey responses. Among other things, this survey requested information on work practices, such as scrap selection and/or cleaning, at foundries that reduced air emissions. Of the 595 iron and steel foundries that provided survey responses, 360 (or 60 percent) of iron and steel foundries indicated that they used some type of scrap selection, cleaning, or inspection program to ensure the quality of scrap metal used by the foundry. The percentage of foundries that specify scrap selection as a work practice to reduce emissions are relatively consistent for foundries operating different furnace types: 45 percent of cupola foundries, 61 percent of electric arc furnace foundries, and 65 percent of electric induction furnace foundries. These percentages indicate that scrap selection or cleaning measures are utilized by a sufficient number of foundries to represent the MACT floor control regardless of the melting furnace. Furthermore, several foundries operate two different types of melting furnaces and these foundries typically specify the same scrap selection for each furnace. Electric induction furnaces have scrap preparation procedures targeted at reducing the amount of water (moisture) in the scrap being changed. These procedures are included for safety concerns specific to electric induction furnace operation and do not necessarily reduce the amount of HAP in the scrap or the HAP emissions from the metal casting department. These procedures account for the slightly higher percentage of electric induction furnaces that report general scrap selection measures. The EPA evaluated survey responses to determine the number of foundries that have specific scrap specifications that limit either HAP contaminants ( e.g. , lead) or contaminants that are precursors to HAP emissions ( e.g. , oil or paint). Many of the responses were general in nature, such as “use clean scrap,” “follow scrap specification,” or “inspect scrap.” However, 71 foundries (12 percent) specified in their survey responses that their scrap selection procedures included limits or restrictions on the amount of organic material in the scrap metal. These organic material restrictions were most commonly expressed as limits or bans on oil, grease, and/or paint in the scrap. Occasionally, restrictions included reference to coolants or rubber components (belts, hoses) in the scrap. In addition, 55 foundries (7.5 percent) specified in their survey responses that their scrap selection procedures included limits or restrictions on the amount of tramp metals in the scrap. These scrap selection metal restrictions were most commonly limits (or bans) on lead, but often included restrictions on the use of galvanized metals (a source of cadmium) and certain alloys (a source of chromium, nickel, or high manganese). Through information collected through site visits and additional queries of large foundries that are anticipated to be major sources of HAP emissions, we have determined that scrap selection and inspection is an integral part of foundry operations needed to ensure the quality (chemistry) of the cast parts. Although some of the foundries visited or queried did not have a written scrap selection plan and did not indicate scrap selection as a work practice used to reduce air emissions, these foundries generally purchased specific grades of scrap and typically included specifications on the scrap (such as “no oil” and/or “no lead”) on their purchase requisitions. Furthermore, these foundries routinely inspected incoming scrap shipments and rejected scrap shipments that did not meet their quality requirements. It is difficult to establish specific emissions reductions achieved by these scrap selection and inspection programs. First, nearly all foundries implement some sort of formal or informal scrap selection and inspection program (to maintain product quality) so it is difficult to assess what the baseline emissions might be without the scrap selection and inspection program. Second, these scrap selection and inspection programs are used in conjunction with other air emissions control technologies used to reduce emissions from the melting furnace and pouring, cooling, and shakeout line exhaust vent streams. The emissions reductions specifically attributable to the scrap selection and inspection program are impossible to separate out. Nonetheless, it is clear that any reduction in HAP content or HAP precursors entering the metal casting department will tend to reduce the emissions of HAP metals and organics from the metal casting department's emissions sources. While a scrap selection and inspection program is expected to reduce HAP emissions, they cannot be expected to eliminate all HAP elements or precursors in the scrap. First, scrap loads are generally large (at least at major source iron and steel foundries) and difficult to inspect. A load of scrap may contain thousands of different pieces, and some scrap may be shredded and bundled. Visual inspections are only able to identify obvious off-specification materials that are on the top of a load. Second, some of the HAP elements are desirable components in the scrap iron and steel which contribute to the overall chemistry of the product and provide valuable properties in the cast metal ( e.g. , manganese and chromium.) Third, even undesirable HAP metals cannot be eliminated from the cast iron and steel as they are trace components in the scrap iron and steel which cannot be separated. For example, all cast iron contains trace amounts of lead (typically 0.5 to 4 percent). As such, a load of scrap meeting a “no lead” scrap specification does not mean that the scrap is lead-free—only that the scrap is free of lead components ( e.g. , batteries or wheel weights). As a scrap selection and inspection program can be reasonably expected to reduce HAP emissions from the metal casting department and since over 6 percent (the median of the top 12 percent) of the foundries employ a scrap selection and inspection program that limits the amount of organic impurities (HAP precursors) and HAP metals in their scrap, we have determined that the MACT floor for existing sources is the work practice of scrap selection and inspection to limit the amount of organic impurities and HAP metals in the scrap used by the metal casting department of the foundry. Considering the practical limitations discussed above, we believe that scrap specifications with specific numeric limits on HAP concentrations cannot be established. A visual inspection program cannot distinguish the trace lead content of the scrap iron and steel parts contained in a load of scrap. The ultimate chemistry of a load of scrap cannot be accurately assessed until after the metal is melted (which is too late to reduce HAP emissions). Additionally, we cannot establish that one scrap selection and inspection program that limits or restricts both organic impurities and HAP metals in the scrap provides higher emissions reductions than an alternative scrap selection and inspection program that limits or restricts both organic impurities and HAP metals. Therefore, the MACT floor for new sources is the same as the MACT floor for existing sources, which is the work practice of a scrap selection and inspection program that specifically addresses methods for reducing the amount of organic impurities and HAP metals in the scrap used by the metal casting department of the foundry. We could identify no other practical pollution prevention method to reduce HAP emissions from the metal casting department based on alternative scrap specifications. Therefore, no emissions reduction options beyond the MACT floor were considered for the scrap selection and inspection program. In summary, we are proposing a pollution prevention work practice standard as a component of MACT for both new and existing foundries to limit both organic and metal HAP emissions throughout the metal casting department. This standard would require facilities to develop and operate according to written specifications and procedures for the selection and inspection of the scrap iron that would limit the amount of organic impurities and HAP metals in the scrap used by the metal casting department of the foundry. The scrap selection and inspection requirements being proposed are intended to ensure that facilities make a reasonable effort to limit the amount of organic impurities and HAP metals in the scrap they process and are based on our understanding of what the best performing facilities are currently doing. A few examples of the types of specifications that we believe are appropriate include bans on lead components ( i.e. , lead batteries, lead pipe, and lead fittings), and that oils and other liquids be drained. We do not believe that limits on chromium or manganese content are appropriate because these elements are required in the cast iron and steel parts. We specifically request comment on the feasibility of implementing the proposed scrap selection and inspection requirements and whether or not the proposed requirements accurately reflect the practices at the best performing facilities. Cupolas A cupola is a vertical cylindrical shaft furnace used to melt iron and steel scrap through combustion of the coke in a forced upward flow of heated air. Virtually all emissions from a cupola are contained in the flow of air exiting the stack of the furnace, which contains organic compounds, CO and PM. The organic compounds, which arise from incomplete combustion of coke and impurities such as oil and grease in the furnace charge, include traces of organic HAP such as acetophenone and pyrene. The PM contains HAP metals such as lead and manganese that are impurities in the scrap. The organic compounds and CO are destroyed by combustion, which may occur spontaneously but is typically initiated by an afterburner located downstream from the charge. The PM are typically controlled by either a fabric filter (baghouse) or a wet scrubber. Cupolas are used to produce molten iron. Because the coke used to fuel the cupola increases the carbon content of the molten metal, cupolas cannot be used to produce molten steel (which requires less than 1 percent carbon content). Unlike other melting furnaces, cupolas produce a continuous supply of molten metal, and they typically have much higher melting capacities than other furnace types. A substantial body of information is available on the types, configurations, and operating conditions of the pollution control devices applied across the iron and steel foundry source category. This information was collected through our comprehensive survey of known iron and steel foundries conducted in 1998. From this survey, detailed data are available for 595 iron and steel foundries which provided survey responses. This survey indicates that 143 cupolas are operated in the U.S. MACT for organic HAP emissions. The primary method for reducing organic HAP emissions from cupolas is an afterburner, which is used on 104 of the 143 existing cupolas. Afterburners are installed primarily to combust CO, a byproduct of the furnace operation, but also act to incinerate any organic compounds present. A typical cupola exhaust will contain CO at levels of 10 percent or higher. The afterburner itself is a relatively simple device consisting of a cylindrical refractory-lined chamber equipped with burners for ignition and sufficiently sized to provide appropriate residence time to achieve complete combustion. Cupola afterburners are typically operated at an ignition temperature of 1,300 °F or higher to combust the CO in the cupola exhaust stream. This temperature is the minimum temperature need to oxidize CO to carbon dioxide. Given that thermal destruction of most organic compounds occurs at 1,200 °F or below, 1 we believe that organic HAP are effectively controlled by an afterburner that effectively oxidizes CO. 1 Air Pollution Engineering Manual. Ed. by A.J. Buonicore and W.T. Davis. Van Nostrand Reinhold, New York, 1992. Page 59. To confirm the effectiveness of an afterburner applied to an iron and steel foundry cupola, we conducted source tests on two cupolas, one equipped with an afterburner followed by a baghouse, and another equipped with an afterburner followed by a venturi scrubber. Three sampling runs were made in one test and four in the other. Test methods used were EPA Method 23, Determination of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans (PCDD/PCDF) From Stationary Sources, and SW-846 Methods 0010 (sampling) and 8270 (analysis), which are applicable to the determination of semivolatile principal organic hazardous compounds from incineration systems. Results of the Method 23 tests showed that measured amounts of PCDD/PCDF were very low and highly variable. In six of the seven runs, concentrations of at least some of the fractions or species analyzed were below the quantitative limits. Within this limitation, total PCDD/PCDF adjusted for the 2,3,7,8-TCDD Toxic Equivalency Factors (TEF) were 1.8 to 5.5 nanograms per dry standard cubic meter (ng/dscm) at 7 percent oxygen in one test, 0.17 to 0.85 ng/dscm in the other. The constituent that was consistently measured in the highest quantifiable levels adjusted by the TEF was the pentachlorinated dibenzofuran fraction, which varied from 1.0 to 3.0 ng/dscm in one test, and 0.07 to 0.40 ng/dscm in the other. Results of SW-846 Methods 0010/8270 also showed very low and highly variable concentrations. Of the 70 compounds analyzed, only 20 were detected in the first test, 25 in the second. Only acetophenone in the first test and acetophenone and pyrene in the second test were detected at levels above the quantitative limits in all runs. The maximum concentration of acetophenone varied from less than 1 to less than 2 parts per billion by volume (ppbv). The maximum concentration of pyrene measured was 0.070 ppbv. The maximum mass emissions rates for both tests were 0.0011 and 0.00013 pounds per hour for acetophenone and pyrene, respectively. These emissions test data suggest that organic HAP emissions from well-controlled cupolas are at or below the detection limits of current EPA methods. It is clear from the data that afterburners are effective in reducing organic HAP emissions. In selecting the MACT floor for organic HAP control from cupolas, we considered the feasibility of an emissions limit for one or more HAP organic compounds. The two tests that we conducted, as discussed above, are the only organic HAP emissions data available from cupolas. We believe the test data are too limited to determine the variability and achievability of an emissions limit for individual organic HAP compounds. We believe CO is an appropriate surrogate for organic HAP emissions from cupolas. As discussed previously, the combustion conditions required to oxidize CO generally exceed the conditions necessary to combust organic HAP compounds. As such, effective control of CO will ensure effective control of organic HAP emissions. However, evaluation of organic HAP emissions from similar exhaust streams in other source categories indicate that reduction of the CO concentration below a few hundred ppmv does not necessarily correlate to additional organic HAP emissions reductions. This is because organic HAP destruction occurs more readily than CO oxidation and because emissions of certain organic HAP such as formaldehyde tend to increase when a combustion device is used to reduce CO concentration. This phenomena is believed to be caused by additional natural gas consumption needed to achieve these very low CO concentrations in the exhaust stream. For these reasons, we believe that CO is a good surrogate for organic HAP at concentrations above several hundred ppmv. However, available data suggest that organic HAP emissions do not continue to decrease when CO concentrations fall below a few hundred ppmv. We have CO emissions data from 17 cupolas. We also examined State requirements for cupolas as they relate to organic HAP emissions limitations. Illinois, Indiana, Michigan, Ohio and Wisconsin are all States that contain a large number of iron and steel foundries. Each of these States have standards that relate to cupola emissions which require the use of an afterburner. The Illinois standard requires that gases are burned in a direct flame afterburner so that the resulting concentration of CO in such gases is less than or equal to 200 ppmv corrected to 50 percent excess air for cupolas with melting rates of greater than five tons per hour. The Ohio and Wisconsin standards both require afterburning at 1,300 °F for 0.3 seconds or greater. The Michigan standard requires cupolas with melting rates of 20 or more tons per hour be equipped with an afterburner control system, or equivalent, which reduces the CO emissions from the ferrous cupola by 90 percent. The Indiana standard simply requires cupolas with melting rates of 10 or more tons per hour be burned in a direct-flame afterburner or boiler. These standards clearly indicate that afterburning is the preferred control measure for organic HAP from cupolas. These State standards are intended to control CO emissions from cupolas either by limiting outlet CO concentration, requiring a minimum CO destruction efficiency, or establishing incinerator operating conditions targeted to achieve CO destruction. Of these State standards, we believe the 200 ppmv limit is the most stringent ( i.e. , requires the greatest CO destruction efficiency) and, therefore, the most effective in organic HAP emissions reductions. And as stated above, further reductions in CO concentration are not expected to result in further organic HAP emissions reductions. We determined the MACT floor for new and existing cupola furnaces by ranking the furnaces for which we have emissions information based on the estimated emissions limitation achieved for that furnace. We have emissions information from the comprehensive survey of known iron and steel foundries for 143 cupolas. Two types of emissions information was used to determine the MACT floor—source test data, and engineering design parameters including afterburner control efficiency and outlet CO concentration design values. Where we had CO emissions source test data for a furnace, we used the emissions data to estimate the emissions limitation achieved for that furnace. We have credible emissions source test data for 13 cupola afterburners controlling 17 cupolas. Each test is comprised of at least three EPA Method 10 sampling runs of approximately 1 hour in duration. While we believe each emissions source test gives a good indication of the level of control achieved by the control device during the time of the emissions test, we do not believe a single emissions source test can be used as an estimate of the long term emissions limitation achieved for that source due to normal variations in process and control device performance and other factors, such as the inherent imprecision of sampling and analysis, which cannot be controlled. We believe that the MACT floor performance level must be achievable under the most adverse circumstances which can reasonably be expected to recur. As such, the MACT floor performance limit must include a consideration for the variability inherent in the process operations and the control device performance. Therefore, we used a statistical method to estimate the emissions limitation achieved by a furnace when emissions source test data were available. For each furnace where emissions source test data were available, the emissions limitation achieved for that furnace was estimated at the 95th percentile outlet CO concentration using a one-sided z-statistic test ( i.e. , the emissions limitation which the furnace is estimated to be able to achieve 95 percent of the time). We evaluated several options to estimate the standard deviation that is needed to perform the z-statistic test. We decided not to estimate the standard deviation for each furnace based on the available emissions data for just that furnace since most furnaces only have three data points to use in estimating the standard deviation, one data point for each run in a three run emissions source test. Instead, we calculated a relative standard deviation (RSD) for each test and then averaged the RSD to provide our best estimate of the variability of the test data. We estimated an average RSD of 0.5 based on a pooling of all of the available emissions source test data. We believe this method adequately accounts for the normal variability in emissions source test data and provides a reasonable estimate of the long term emissions limitation achieved by a furnace. When emissions source test data were not available for a furnace, we estimated the emissions limitation achieved by that furnace based on other emissions information including afterburner control efficiency and outlet CO concentration design values. These data were used to estimate the emission reduction limitation achieved for the remaining 126 cupolas where we did not have stack test emissions data. Additional information on the ranking of the furnaces used to determine the MACT floor, including the data used, details of the statistical analysis performed, and the estimated emissions limitation achieved for each furnace, is available in the docket for the proposed rule. We have interpreted the MACT floor for existing sources ( i.e. , the average emissions limitation achieved by the best performing 12 percent of existing sources) to be the performance achieved by the median source of the top 12 percent best performing sources, which would be the 6th percentile unit. As we have emissions information on 143 cupola sources, the 6th percentile would be the 9th best performing unit (143 × 0.06 = 8.6). Based on our ranking of the emissions limitation achieved by the existing cupola afterburners, we determined that the MACT floor for organic HAP control at existing sources is a CO emissions concentration of 200 ppmv. Based on available emissions test data, we believe that existing sources can achieve an emissions limitation of 200 ppmv using a well-designed and operated afterburner to control emissions. For new sources, the MACT floor is the emissions control that is achieved in practice by the best-controlled similar source. Based on our ranking, the best-controlled similar source has achieved a CO emissions limitation of 20 ppmv. However, evaluation of organic HAP emissions from similar exhaust streams in other source categories indicate that reduction of the CO concentration below a few hundred ppmv does not necessarily correlate to additional organic HAP emissions reductions. This is because organic HAP destruction occurs more readily than CO oxidation, and because emissions of certain organic HAP such as formaldehyde tend to increase due to the significant increase in natural gas consumption, which results in formaldehyde emissions, needed to achieve these very low CO concentrations in the exhaust stream. We believe a CO concentration of 200 ppmv is a good indicator of proper destruction of organic HAP. However, we do not believe that further reduction in CO concentrations will result in additional organic HAP emissions reduction beyond that achieved by an afterburner operated to meet a 200 ppmv CO concentration limit. Therefore, we established the MACT floor for organic HAP emissions from new sources as a CO emissions limit of 200 ppmv. Next, we evaluated regulatory options that were more stringent than the MACT floor (beyond-the-floor) options. We could not identify any technically feasible options that can reduce organic HAP emissions below the level of the new source MACT floor of 200 ppmv. Therefore, the proposed MACT standards are based on the MACT floor performance limits for new and existing sources. For existing and new sources, the MACT standard for organic HAP emissions is a CO emissions limit of 200 ppmv. MACT for HAP metal emissions. Metal HAP emissions from cupolas are controlled by baghouses, venturi scrubbers, and electrostatic precipitators (ESP). Based on industry survey data available for 143 cupolas in the iron and steel foundries source category, there are 58 cupolas (40 percent) controlled by baghouses, 76 (53 percent) controlled by venturi scrubbers, 1 (1 percent) controlled by an ESP, and 9 (6 percent) that are uncontrolled for metal HAP. We have very limited metal HAP emissions data. Specifically, the only data on metal HAP emissions from cupolas include two source tests we conducted on two cupolas: one controlled by a baghouse, and the other controlled by a venturi scrubber. The two source tests demonstrate that a baghouse achieves lower HAP metal emissions than a venturi scrubber. Concentrations of lead and manganese, the two HAP metals found to be present in the highest concentrations, were substantially lower in the baghouse exhaust gas than in the wet scrubber exhaust gas. The average lead concentration measured was 42 micrograms per cubic meter (μg/dscm) from the baghouse, and 240 μg/dscm from the scrubber. The average manganese concentration was 21 μg/dscm from the baghouse, and 1,570 μg/dscm from the scrubber. While these data are useful in demonstrating that baghouses do achieve greater control of metal HAP emissions than venturi scrubbers, they are inadequate for the purpose of establishing a specific emissions standard (or standards) for metal HAP. We also have emissions data for PM from source tests conducted on 36 cupolas: 12 controlled by baghouses, 23 controlled by venturi scrubbers, and 1 controlled by an ESP. For metal HAP compounds, we believe PM to be a reasonable surrogate. The metal compounds of concern are in fact a component of the PM contained in the cupola exhaust. As a result, effective control of cupola PM emissions will also result in effective control of HAP metals. Because emissions data for PM are available, and because PM can reasonably serve as a surrogate for metal HAP from cupolas, we elected to establish PM limits to control metal HAP emissions from cupolas. We also looked at existing State PM emissions limitations and discovered that they are much more lenient than actual emissions. 2 Therefore, we believe that PM emissions limitations that are specified in air regulations and facility operating permits applicable to iron and steel foundries cannot function as a reasonable proxy for actual emissions and, as such, are not appropriate for establishing the MACT floor for metal HAP or for PM as a surrogate of metal HAP. 2 For example, Indiana, Michigan, and Wisconsin are States containing a large number of iron and steel foundries. These states have PM concentration limits for cupolas of 0.08 gr/dscf or higher. By contrast, exhaust gas emissions from 27 of the 34 cupolas for which we have data show measured PM concentrations of 0.07 gr/dscf or lower. Also, the average PM concentrations from all 12 of the cupolas with baghouses were 0.005 gr/dscf or lower. We determined the MACT floor for new and existing cupola furnaces by ranking the furnaces for which we have emissions information based on the estimated emissions limitation achieved for that furnace. We have emissions information from the comprehensive survey of known iron and steel foundries for 143 cupolas. Two types of emissions information was used to determine the MACT floor—source test data, and engineering design parameters including control type and outlet PM concentration design values. Where we had emissions source test data for a furnace, we used the emissions data to estimate the emissions limitation achieved for that furnace. We have credible emissions source test data for 36 cupolas including 12 controlled by baghouses, 23 controlled by venturi scrubbers, and 1 controlled by an ESP. Each test is comprised of at least three EPA Method 5 sampling runs of approximately 1 hour in duration. We were careful to include only the data representing the Method 5 PM ( i.e. , “front half” PM catch), as some foundries reported both front and back half PM catches. While we believe each emissions source test gives a good indication of the level of control achieved by the control device during the time of the emissions test, we do not believe a single emissions source test can be used as an estimate of the long term emissions limitation achieved for that source due to normal variations in process and control device performance and other factors, such as the inherent imprecision of sampling and analysis, which cannot be controlled. We believe that the MACT floor performance level must be achievable “under the most adverse circumstances which can reasonably be expected to recur.” As such, the MACT floor performance limit must include a consideration for the variability inherent in the process operations and the control device performance. Therefore, we used a statistical method to estimate the emissions limitation achieved by a furnace when emissions source test data were available. For each furnace where emissions source test data were available, the emissions limitation achieved for that furnace was estimated at the 95th percentile outlet PM concentration using a one-sided z-statistic test ( i.e. , the emissions limitation which the furnace is estimated to be able to achieve 95 percent of the time.) We evaluated several options to estimate the standard deviation that is needed to perform the z-statistic test. We decided not to estimate the standard deviation for each furnace based on the available emissions data for just that furnace since most furnaces only have three data points to use in estimating the standard deviation, one data point for each run in a three run emissions source test. We also decided not to estimate the standard deviation for a furnace based on just the data available for that furnace type because we have very limited information on electric arc furnaces, and because the standard deviation estimates the three types of furnaces were very similar. An analysis of variance was performed on the data and there was no statistically significant difference in the standard deviation estimates for the three furnace types. Ultimately, we estimated an average RSD of 0.4 based on a pooling of all of the available emissions source test data for all furnaces types controlled by baghouses. Note that data on venturi scrubbers and ESP were not used in estimating the RSD because the available emissions source test data clearly demonstrated that the furnaces controlled with these devices were not among the best performing 12 percent of sources. We believe this method adequately accounts for the normal variability in emissions source test data and provides a reasonable estimate of the long term emissions limitation achieved by a furnace. Additional information on the statistical analysis used to estimate the emissions limitation achieved by a furnace, including the data used and the complete ranking of furnaces, is available in the docket for the proposed rule. When emissions source test data were not available, we estimated the emissions limitation achieved by that furnace based on other emissions information including control type and outlet PM concentration design values. These data were used to estimate the emission reduction limitation achieved for the remaining 107 cupolas where we did not have stack test emissions data. Additional information on the ranking of the furnaces used to determine the MACT floor, including the data used, details of the statistical analysis performed, and the estimated emissions limitation achieved for each furnace, is available in the docket for the proposed rule. We have interpreted the MACT floor for existing sources ( i.e. , the average emissions limitation achieved by the best performing 12 percent of existing sources) to be the performance achieved by the median source of the top 12 percent best performing sources, which would be the 6th percentile unit. It is reasonable to use the median to represent the emissions reductions achieved by the top performing units because the median represents the emissions reductions achieved by an actual facility and, therefore, is representative of the what can be achieved with the emissions controls used at that facility. As we have emissions information on 143 cupola sources, the 6th percentile would be the 9th best performing units (143 x 0.06 = 8.6). Based on our ranking of the emissions limitation achieved by the existing cupola furnaces, we determined that the MACT floor for metal HAP control at existing sources is a PM emissions concentration of 0.005 gr/dscf. Based on available emissions test data, we believe that existing sources can achieve an emissions limitation of 0.005 gr/dscf using a well-designed and operated baghouse to control emissions. For new sources, the MACT floor is the emissions control that is achieved in practice by the best-controlled similar source. Based on our ranking, the best-controlled similar source achieves an emissions limitation of 0.001 gr/dscf. Two cupolas were identified that have achieved average outlet PM concentrations of 0.001 gr/dscf. Both of these cupola systems employ a novel pulse-jet baghouse with horizontally supported bags (referred to as a horizontal baghouse) that exhibited significantly better performance, based on available emissions source test data, than any of the traditionally-designed (vertically hanging bag) baghouses. In addition, one of the two facilities was designed with a vendor guaranteed performance level of 0.001 gr/dscf, and five emissions source tests have been conducted on this baghouse demonstrating that it is able to achieve a PM concentration of 0.001 gr/dscf. Therefore, the MACT floor for metal HAP control at new sources is determined to be an average PM concentration of 0.001 gr/dscf or less. Next, we evaluated regulatory options that were more stringent than the MACT floor (beyond-the-floor) options. We could not identify any technically feasible options that can reduce metal HAP emissions below the level of the new source MACT floor of 0.001 gr/dscf. For existing sources, we evaluated the option of requiring existing sources to meet the new source MACT floor of 0.001 gr/dscf. Based on the available emissions source test data, it is likely that existing sources would have to install and operate a horizontal baghouse in order to achieve an emissions limit of 0.001 gr/dscf. Since only two furnaces are currently equipped with horizontal baghouses, the rest of the existing sources would have to remove any existing controls (including traditional baghouses) and replace them with horizontal baghouses. We estimated the incremental annualized cost of requiring all existing sources to meet a 0.001 gr/dscf standard over the MACT floor level of 0.005 gr/dscf at $6.3 million dollars per year. We estimated the additional HAP emissions reduction that would be achieved at 13 tpy. Therefore, the additional cost per ton of additional HAP removed is $480,000 per ton of HAP emissions reduced for the beyond-the-floor alternative. We rejected the beyond-the-floor control option because of its high incremental costs per ton of HAP removed. The proposed MACT standards are based on the MACT floor performance limits for new and existing sources. For existing sources, the MACT standard for cupolas is an average PM concentration of 0.005 gr/dscf or less. For new sources, the proposed MACT standard for cupolas is an average PM concentration of 0.001 gr/dscf or less. Electric Induction Furnaces and Scrap Preheaters An electric induction furnace is a vessel in which forms of iron and steel, such as scrap and foundry returns, are melted though resistance heating by an electric current. The current is induced in the metal charge by passing an alternating current through a coil that surrounds either the charge (the coreless electric induction furnace) or a pool of molten metal at the bottom of the vessel (the channel electric induction furnace). An electric induction furnace operates in batch mode, an operating cycle consisting of charging, melting, backcharging (adding a second load of charge after the first load has melted, which is optional), and tapping. One major characteristic of melting operations using an electric induction furnace is that scrap feed for an electric induction furnace is commonly preheated prior to charging to the furnace. When used, preheating is almost universally effected by direct exposure of the scrap metal to a gas flame. Scrap preheaters are used primarily to eliminate volatile substances, including water, that may vaporize suddenly and cause an explosion if added to a molten charge or heel in the furnace. Scrap preheaters are also used because the cost of initial scrap heating with a gas flame (up to approximately 800 °F) is less costly than heating with electricity. Scrap preheaters are used solely for electric induction furnaces. Where used, scrap preheaters are considered to be an integral part of the electric induction furnace metal melting operation, and they generally share a common PM control device with the electric induction furnace. Therefore, we have included scrap preheaters in the evaluation of electric induction furnace control requirements. Another significant characteristic of electric induction furnaces is that they typically have low melting rates and are generally used at smaller iron and steel foundries. From the comprehensive survey of iron and steel foundries, there are 1,394 electric induction furnaces at the 595 iron and steel foundries that provided survey responses. Although there are almost ten times more electric induction furnaces than cupolas, the total amount of metal melted nationwide using electric induction furnaces is only about 65 percent of the metal melted in cupolas. The median size electric induction furnace has a melting capacity of 1 ton/hr, and 95 percent of all electric induction furnaces at iron and steel foundries have melting capacities under 10 tons/hr. Predominately, electric induction furnaces are used at small foundries or for small-production specialty-metal castings ( e.g. , high alloy iron castings) at larger foundries. Emissions from electric induction furnaces are generally low and primarily consist of PM and metal fumes. MACT for organic HAP emissions. Electric induction furnaces are not considered to be a significant source of organic HAP emissions, primarily due to safety concerns with adding volatile substances to the furnace. To avoid explosion hazards, tramp materials such as oil and grease that are commonly present in scrap are removed either by the use of a scrap preheater, by cleaning and drying the scrap on-site, or are eliminated by purchasing only pre-cleaned or ingot scrap. As such, organic HAP emissions from electric induction furnaces are negligible and establishing a limit would not result in measurable emissions reductions. Therefore, we are not proposing an emissions limit regulating organic HAP emissions from electric induction furnaces. Scrap preheaters are a potential source of organic HAP due to the volatilization and incomplete combustion of oil and grease that may be present in the scrap. Direct flame heating is used for most of the 177 scrap preheaters operated at iron and steel foundries. This method is anticipated to effect a reduction in organic HAP by combusting most of the organic materials that may be present in the scrap. A second method of control is afterburning of exhaust gases, which is used for 12 scrap preheaters at two foundries. Six of the scrap preheaters for which afterburning is used are at one foundry that preheats scrap in vessels that are so large that the flame may not penetrate the entire charge, thus allowing some organic tramp materials to be volatilized and escape without being combusted. We do not have actual organic HAP emissions data; neither do we have data on emissions that can function as a surrogate for organic HAP. Therefore, we cannot use scrap preheater emissions data to directly calculate an emissions limit for organic HAP from scrap preheaters. We do have significant data on the methods currently used at scrap preheaters that reduce organic HAP emissions and well-established information on the performance and effectiveness of these methods, and we can use these data to estimate the level of control that these operations currently achieve. Afterburning is used at 12 (6.8 percent) of the 177 scrap preheaters, and these scrap preheaters are located at three iron and steel foundries (6 scrap preheaters at each of 2 foundries). As these afterburners are used in conjunction with direct flame preheaters, it is reasonable to conclude that these systems achieve the greatest organic HAP emissions reductions compared to scrap preheaters operated without any additional control systems. Because more than 6 percent ( i.e. , greater than the median of the top 12 percent) of the scrap preheaters are equipped with afterburners, the MACT floor is represented by the performance achieved by scrap preheater afterburners. Without additional data to characterize the organic HAP removal performance of scrap preheater afterburners, we relied on our extensive experience with, and knowledge of, the capabilities of thermal incinerators at destroying organic emissions. Because afterburners are thermal incinerators, it is reasonable to conclude that the performance of scrap preheater afterburners is comparable to the performance of thermal incinerators generally. We have over 20 years of experience in evaluating the performance of thermal incinerators on a variety of organic emissions sources. Based on our experience, we have identified a well-established presumption that a well-designed and operated thermal incinerator or afterburner is capable of achieving a 98 percent reduction or an outlet concentration of 20 ppmv of VOC. There is no reason to believe that there is anything about the thermal incinerators used in conjunction with scrap preheaters that would result in any poorer or more efficient HAP reduction performance. We believe that VOC is a reasonable surrogate for organic HAP emissions from scrap preheaters because organic HAP emissions are a significant component of the VOC emissions. Furthermore, effective control of VOC emissions will result in effective control of organic HAP emissions. Unlike the emissions from cupolas, which are high in CO content due to the incomplete combustion of coke, CO is not a good surrogate for organic HAP emissions from scrap preheaters. Scrap preheater emissions are already low in CO content because the preheaters use natural gas as fuel and operate with excess oxygen. Therefore, we selected VOC as the surrogate for organic HAP emissions from scrap preheaters. We have determined that afterburners represent the MACT floor control for scrap preheaters. We believe that the performance of these scrap preheater afterburners is comparable to the performance of thermal incinerators on other organic emissions sources, and that VOC is a reasonable surrogate for organic HAP emissions from scrap preheaters. Accordingly, we have established the existing source MACT floor for organic HAP emissions from scrap preheaters as a 98 percent reduction or an outlet concentration of 20 ppmv of VOC. We do not know of any control option that would result in lower organic HAP emissions than can be achieved by afterburning. As such, the MACT floor for new sources is the same as the MACT floor for existing sources. Therefore, the proposed MACT standard for both existing and new scrap preheaters is a VOC reduction of 98 percent or greater, or an outlet concentration of 20 ppmv if a 98 percent reduction would result in an outlet concentration below 20 ppmv. Because we do not have emissions data from scrap preheaters that directly or indirectly measure organic HAP, we specifically request comment on the proposed performance limits for organic HAP emissions from scrap preheaters. We believe this emissions limit is appropriate and achievable by scrap preheaters equipped with afterburners. Because the direct flame used by some scrap preheaters can itself function as a thermal incinerator, we believe that most scrap preheaters units that employ direct flame preheating will be able to meet this limit without the application of afterburners. MACT for metal HAP emissions. Both electric induction furnaces and scrap preheaters are sources of metal HAP. As discussed earlier, reduction of metal HAP emissions is accomplished by PM control since the metal HAP of concern are primarily contained in the particulate emissions. Baghouses, along with a few cartridge filters, are the devices most commonly used for PM controls on the 1,394 electric induction furnaces operated at iron and steel foundries. Baghouses and cartridge filters (or fabric filters) are used for controlling melting operations for 388 electric induction furnaces (28 percent), wet scrubbers are used for 21 electric induction furnaces (1.5 percent), and cyclones are used for 2 electric induction furnaces (0.1 percent). Electric induction furnaces also have the potential to emit PM during charging and tapping operations. These operations are generally controlled by the same control device used to control melting operation emissions. As such, fabric filters also dominate the charging and tapping emissions controls. Charging is controlled by fabric filters for 358 electric induction furnaces (26 percent) and tapping is controlled by fabric filters for 309 electric induction furnaces (22 percent). Over 70 percent of electric induction furnaces (961) do not use PM controls for any phase of operation. Of the 177 scrap preheaters used at iron and steel foundries, 64 have baghouse controls for the discharging phase of operation; 23 of the 64 use the same controls for heating, and 25 of the 64 use the same controls for loading. Other controls used for PM are cyclones (used for 11 scrap preheaters) and wet scrubbers (two scrap preheaters). Approximately half of the scrap preheaters do not use controls for any phase of operation. Of the 64 scrap preheaters that are controlled by baghouses, 59 are employed in conjunction with electric induction furnaces that are also equipped with baghouses. Of those 59 scrap preheaters, 43 are controlled by the same baghouses as their associated electric induction furnace. We are proposing a single MACT limit for both electric induction furnaces and scrap preheaters because PM emissions from scrap preheaters are typically controlled with the same control device used to control the PM emissions from their associated electric induction furnace. Data for actual emissions of HAP metals are available from only one electric induction furnace. These data are insufficient to characterize HAP emissions from iron and steel foundries. However, as we explained earlier, we believe PM to be a reasonable surrogate for HAP metal compounds for electric induction furnaces and scrap preheater/electric induction furnace systems. The metal HAP compounds of concern are in fact a component of the PM contained in the scrap preheater and electric induction furnace exhaust. As a result, effective control of PM emissions will also result in effective control of HAP metals. Outlet PM concentration data are available for 19 fabric filters (17 baghouses and 2 cartridge filters) used to control emissions from 57 electric induction furnaces and 16 scrap preheaters, 1 venturi scrubber on 2 electric induction furnaces, 1 cyclone on 2 electric induction furnaces, and 7 uncontrolled electric induction furnaces. Based on the relative availability of PM versus HAP metal emissions data and based on the nature of the metal HAP emissions (being particulate in nature), we elected to use PM as a surrogate for metal HAP emissions in establishing the MACT floor. We also looked at Federally-enforceable emissions limitations as a possible surrogate for actual electric induction furnace and scrap preheater HAP emissions data. However, the State limitations are much more lenient than actual emissions and cannot serve as a proxy for the level of performance that such units actually achieve. 3 3 Wisconsin, Indiana, Ohio, Illinois, and Alabama have PM emissions limits that apply to melting furnace and general foundry operations. In these States, PM emissions limits are 0.05 gr/dscf or higher. In contrast, measured PM concentration in electric induction furnace baghouse offgases are generally less than 0.005 gr/dscf. We determined the MACT floor for new and existing electric induction furnaces and scrap preheaters by ranking the furnaces for which we have emissions information based on the estimated emissions limitation achieved for that furnace. We have emissions information from the comprehensive survey of known iron and steel foundries for 1,394 electric induction furnaces and scrap preheater/electric induction furnace systems. Two types of emissions information was used to determine the MACT floor—source test data, and engineering design parameters including control type and outlet PM concentration design values. As with cupola furnaces, where we had emissions source test data for a furnace, we used the emissions data to estimate the emissions limitation achieved for that furnace. We have credible emissions source test data for 57 electric induction furnaces controlled by 19 fabric filters (17 baghouses and 2 cartridge filters), 2 electric induction furnaces controlled by venturi scrubbers, 2 electric induction furnaces controlled by cyclones, and 7 uncontrolled electric induction furnaces. Each test is comprised of at least three EPA Method 5 runs (except two tests at one foundry that employed EPA Method 17) with sampling runs of approximately 1 hour in duration. As discussed earlier, the MACT floor performance limit must include a consideration for the variability inherent in the process operations and the control device performance. Therefore, we used a statistical method to estimate the emissions limitation achieved by a furnace when emissions source test data were available. For each furnace where emissions source test data were available, the emissions limitation achieved for that furnace was estimated at the upper 95th percentile outlet PM concentration using a one-sided z-statistic test ( i.e. , the emissions limitation which the furnace is estimated to be able to achieve 95 percent of the time.) We believe this method adequately accounts for the normal variability in emissions source test data and provides a reasonable estimate of the emissions limitation achieved by a furnace. Additional information on the statistical analysis used to estimate the emissions limitation achieved by a furnace, including the data used and the complete ranking of furnaces, is available in the docket for the proposed rule. When emissions source test data were not available, we estimated the emissions limitation achieved by that furnace based on other emissions information from the detailed survey including control type, outlet PM concentration design values, and design PM removal efficiencies. These data were used to estimate the emission reduction limitation achieved for the remaining 1,337 electric induction furnaces and scrap preheaters where we did not have stack test emissions data. Additional information on the ranking of the sources used to determine the MACT floor, including the data used, details of the statistical analysis performed, and the estimated emissions limitation achieved for each furnace, is available in the docket for the proposed rule. We have interpreted the MACT floor for existing sources ( i.e., the average emissions limitation achieved by the best performing 12 percent of existing sources) to be the performance achieved by the median source of the top 12 percent best performing sources, which would be the 6th percentile unit. Again, it is reasonable to use the median to represent the emissions reductions achieved by the top performing units because the median represents the emissions reductions achieved by an actual facility and, therefore, is representative of the what can be achieved with the emissions controls used at that facility. As there is emissions information on 1,394 electric induction furnaces and scrap preheater/electric induction furnace sources, the 6th percentile would be represented by the 84th best performing units (1,394 × 0.06 = 83.6). Based on our ranking of the emissions limitation achieved by the existing electric induction furnaces and scrap preheaters/electric induction furnaces, we determined that the MACT floor for metal HAP control at existing sources is a PM emissions concentration of 0.005 gr/dscf. We believe that existing sources can achieve an emissions limitation of 0.005 gr/dscf using a well-designed and operated baghouse to control emissions. For new sources, the MACT floor is the emissions control that is achieved in practice by the best-controlled similar source. Based on our ranking, the best-controlled similar source achieves an emissions limitation of 0.001 gr/dscf. This source actually employs a three stage control system: a baghouse (positive pressure, shaker, polyester, air-to-cloth ratio of 3 ft/min), followed by a set of cartridge filters, followed by high efficiency particulate arrester (HEPA) filters. There are also several traditional baghouse units that are achieving this performance level, and these units span the range of potential electric induction furnaces and scrap preheater control configurations. Furthermore, as discussed earlier, we believe baghouse technologies exist that can effectively meet this performance level, and we believe this baghouse technology can be applied to electric induction furnace and scrap preheater emissions sources. Based on the available information, the MACT floor performance level for new electric induction furnaces and scrap preheaters emissions sources is determined to be an average PM concentration of 0.001 gr/dscf or less. Next we evaluated regulatory options that were more stringent than the MACT floor (beyond-the-floor) options. We could not identify any technically feasible options that can reduce metal HAP emissions below the level of the new source MACT floor of 0.001 gr/dscf. For existing sources, we evaluated the option of requiring existing sources to meet a more stringent limit, including the new source MACT floor of 0.001 gr/dscf. However, we believe that a more stringent limit is not justified for existing electric induction furnace and scrap preheater emissions sources because many units that could currently meet the existing source MACT floor would need to purchase new baghouse control systems and remove and dispose of their existing baghouses. The incremental cost per ton of HAP removed for a 0.001 gr/dscf emissions limit for existing electric induction furnace and scrap preheater sources is roughly $400,000 to $500,000 per ton of HAP metal reduced. Therefore, the proposed MACT standards for electric induction furnaces and scrap preheaters are based on the MACT floor performance limits for new and existing sources. For existing sources, the MACT standard for electric induction furnaces and scrap preheaters is an average PM concentration of 0.005 gr/dscf. For new sources, the MACT standard for electric induction furnaces and scrap preheaters is an average PM concentration of 0.001 gr/dscf. Electric Arc Furnaces An electric arc furnace is a vessel in which forms of iron and steel such as scrap and foundry returns are melted through resistance heating by an electric current. The current flows through the arcs formed between electrodes (that are slowly lowered into the furnace) and the surface of the metal and also through the metal between the arc paths. Like an electric induction furnace, an electric arc furnace operates in batch mode; an operating cycle consists of charging the furnace, melting the charge, backcharging (which is optional), and tapping the molten metal. Electric arc furnaces are primarily used in the steel foundry industry with limited applications at iron foundries. Based on the information collected through our comprehensive survey of iron foundries, 81 iron and steel foundries (out of 595 respondents) reported using electric arc furnaces for their melting operations. These 83 iron and steel foundries operate a total of 163 melting electric arc furnaces. MACT for organic HAP emissions. We have no organic HAP specific emissions data for electric arc furnaces. However, electric arc furnaces are not anticipated to be a significant organic HAP emissions source. Total hydrocarbon concentrations measured in the exhaust stream show very low organic concentrations (less than 1 ppmv). Small amounts of organic HAP emissions may arise from electric arc furnaces due to the vaporization or partial combustion of contaminant oils and greases that may be present in the scrap. Implementation of a scrap selection and inspection program that limits the amount of organic impurities in the scrap used, which has previously been determined to be a part of the MACT floor for the metal casting department of the foundry, should minimize the potential for organic emissions from the electric arc furnace. Furthermore, it is likely that most trace organic materials present in the scrap after scrap selection and inspection will be pyrolyzed in the electric arc furnace due to the heat associated with the melting operation. Thus, we believe that organic HAP emissions from electric arc furnaces are negligible, and that the performance of these units with respect to organic HAP can not be measurably improved. Moreover, no iron and steel foundry operates an emissions control system that would further reduce the organic HAP emissions, if any exist, from the electric arc furnace exhaust stream. Because no units currently reduce organic HAP emissions from electric arc furnaces in the iron and steel foundry industry, the MACT floor for organic HAP from electric arc furnaces (for both new and existing sources) would be no reduction in emissions. Because the organic concentrations are already so low, no technically feasible control technologies can be identified that could reduce the organic emissions from electric arc furnaces. Therefore, aside from the scrap selection and inspection requirements, no organic HAP emissions standards are proposed for electric arc furnaces. MACT for metal HAP emissions. The PM emissions from electric arc furnaces contain metal HAP such as lead and manganese that are trace components in the scrap metal. The metal HAP emissions are reduced primarily by PM control. Baghouses, the only means used for controlling PM emissions for electric arc furnaces, are employed for 81 charging/ [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A02-31234. Public record. Not legal advice.