United States Environmental Protection Agency Office of Air Quality Planning and Standards Research Triangle Park NC 27711 EPA 450/3-92/007(3) June 1993 Air ©EPA Guidelines for MACT PROPOSAL Determinations under Section 112(j) ------- ABSTRACT Section 112(j) of the Clean Air Act as amended in 1990 requires major sources within a source category to apply for a Title V permit should the Environmental Protection Agency fail to promulgate emission standards for that source category by the date specified in the regulatory schedule established through Section 112(i) of the Act. The Title V permit application must demonstrate the major source's ability to achieve a maximum achievable control technology (MACT) emission limitation for all hazardous air pollutant emissions. Regulations to implement Section 112(j) will be published in 40 CFR Part 63, Subpart B. This document provides guidance for complying with these regulations by identifying and evaluating control technology options to determine the MACT emission limitation. U.S. Environmental Protection Agency Region 5, Libra."..- 'PI-12J) 77 West Jackso.i • " ;.>varrt Chicago, IL 60604-3590 ------- Proposal June 1993 Table of Contents Introduction iv Chapter 1.0 An overview of the MACT Determination Process.... l 1.1 Overview of Statutory Requirements 1 1.2 Overview of the Regulatory Requirements 4 1.3 Administrative Review Process for for New Emission Units 7 1.3.1 Application Process 7 1.3.2 Contents of Application 14 Chapter 2.0 The MACT Determination... a Permitting Agency' s Perspective 16 2.1 Criteria for the MACT Determination 16 2.2 Compliance Provisions 20 2.3 Available Control Technologies 23 2.4 Approaches to the MACT Determination 25 2.5 General Permits 28 Chapter 3.0 The MACT Analysis 30 3.1 Overview of the MACT Analysis Process 31 3.2 A Detailed Look at the MACT Analysis 36 3.3 Determining the MACT-Affected Source on a Case-by-Case Basis 47 3.4 Similar Emission Units 53 3. 5 Subcategorization 57 Chapter 4 . 0 The MACT Floor Finding 58 4.1 Calculation of the MACT Floor 62 4.2 Method 1- Computing the MACT floor using existing State and Local Regulations 68 4.3 Method 2 - Computing the MACT Floor using Control Efficiency Ratings 73 4.4 Method 3 - Computing the MACT Floor using Emission Reduction Ratios (ERR) 77 4.5 Exceptions to the Emission Reduction Ratios 83 4.6 Other Methods to Compute the MACT Floor 84 Chapter 5.0 Costs, Non-Air Quality Health and Environmental Impacts and Energy Requirements 79 5.1 Costs Impacts 81 5.2 Environmental Impacts 84 5.3 Energy Requirements 86 ------- Proposal June 1993 ,88 Chapter 6.0 Information Sources References Appendix A Examples of MACT Analyses A-l Appendix B Forum of Anticipated Questions B-l Appendix C Definitions c~1 Appendix D List of Major Source Categories D-l 11 ------- Proposal June 1993 LIST OF FIGURES Figure 1 Example Notice of MACT Approval 10 Figure 2 Three Tiers to the MACT Analysis 32 Figure 3 Acceptable Methods for Determining the MACT Floor 62 Figure 4 Using State or Local Air Pollution Regulations to compute the MACT Floor 69 Figure 5 Analysis of State Regulations for Emission Unit X 71 Figure 6 Using Control Efficiency Ratings to Compute teh MACT Floor 74 Figure 7 Using Emission Reduction Ratios to Compute the MACT Floor 78 111 ------- Proposal June 1993 Introduction This guidance document is designed to clarify the statutory and regulatory requirements for MACT determinations as required by Section 112(j) of the Clean Air Act (the Act) as amended in 1990. It sets forth procedures for determining emission limitations based on maximum achievable control technology for major sources who are required to apply for a new Title V permit, revise an existing permit, or apply for a Notice of MACT approval because the promulgation deadline for a MACT standard was missed by greater than 18 months for an applicable source category. The manual is divided into five chapters and a four section appendix. Chapter 1 of this manual provides an overview of the statutory and regulatory requirements and discusses the procedures for applying for a Notice of MACT approval. Chapter 2 outlines the criteria a permitting agency should use when evaluating applications as well as possible approaches permitting agencies may use for determining the appropriate level of control for each source. Chapter 3 describes the process for selecting a control technology that meets the criteria discussed in Chapter 2. Chapter 4 describes the analysis that may be required to assess the costs of achieving the emission reduction, and any non-air quality health and environmental impacts and energy requirements associated with use of different control options. Chapter 5 discusses the national databases that may assist in the IV ------- Proposal June 1993 collection of available information. Part A of the Appendix illustrates examples for defining a MACT-affected emission unit, and selecting a control technology to meet MACT. Part B is a question and answer forum. It is designed to deal with detailed questions on applicability and other issues. Part C of the Appendix contains a glossary of terms and definitions. In Appendix D, a complete list of source categories of major sources is provided. This listing is current only to the date of this publication. Readers are referred to the Federal Register for any changes to this listing. It is hoped that this guidance document contains useful information for implementation of MACT determinations. For more information on MACT determinations, the reader is advised to read 40 CFR Part 63, Subpart B, and Section 112 of the Act. ------- Proposal June 1993 Chapter 1.0 An Overview of the MACT Determination Process for Section 112(j) 1.1 Overview of Statutory Requirements Beginning after the effective date of an approved permit program, (but no sooner than May 15, 1994,) Section 112(j) of the Clean Air Act as amended in 1990 (The Act), requires an owner or operator of a major source to submit either a new Title V permit application or a revision to an existing permit if such major source is part of a source category for which the promulgation deadline for a relevant Section 112(d) or 112(h) standard has been missed by 18 months. The promulgation deadline for each source category will be established through the regulatory schedule in accordance with Section 112(e) of the Act. A proposed regulatory schedule was published on September 24, 1992 in the Federal Register. Section 112 (j) also requires States or local agencies with approved permit programs to issue permits or revise existing permits for all of these major sources. These permits must contain either an equivalent emission limitation or an alternate emission limitation for the control of hazardous air pollutants (HAPs) from the major source. An equivalent emission limitation, also referred to as a MACT emission limitation, will be determined on a case-by-case by the permitting agency for each ------- Proposal June 1993 source category that becomes subject to the provisions of Section 112(j). The MACT emission limitation will be "equivalent" to the emission limitation which the source category would have been subject to if a relevant standard had been promulgated under Section 112(d) (or Section 112(h)). In accordance with Section 112(d), the MACT emission limitation will require a maximum degree of reduction of hazardous air pollutant emissions (HAPs) taking into consideration the costs of achieving such emission reductions, and any non-air quality health and environmental impacts and energy requirements. For new sources, the MACT emission limitation will be no less stringent than the emission control that is achieved in practice by the best controlled similar source. For existing sources the MACT emission limitation will be no less stringent than: the average emission limitation achieved by the best performing 12 percent of the existing sources (for which the Administrator has emissions information), excluding those sources that have, within 18 months before the emission standard is proposed or within 30 months before such standard is promulgated, whichever is later, first achieved a level of emission rate or emission reduction which complies, or would comply if the source is not subject to such standard, with the lowest achievable emission rate (as defined by Section 171 (of the Act)) applicable to the 2 ------- Proposal June 1993 source category and prevailing at the time, in the category or subcategory for categories and subcategories with 30 or more sources; or, the average emission limitation achieved by the best performing 5 sources (for which the Administrator has or could reasonably obtain emissions information) in the category or subcategory for categories or subcategories with fewer than 30 sources. These minimum requirements for the MACT emission limitation for new and existing sources are termed the "maximum achievable control technology (MACT) floor". An alternate emission limitation is a voluntary emission limitation that an owner or operator of a major source has agreed to achieve through the early reductions program. (See 57 FR 61970.) The alternate emission limitation can be written into the permit in lieu of an equivalent emission limitation only if the source has achieved the required reduction in HAP emissions before the missed promulgation deadline for the relevant Section 112(d) (or 112(h)) standard. Section 112 (j) also requires EPA to establish requirements for owners or operators and reviewing agencies to carry out the intent of Section 112(j). These requirements are contained in Chapter 40, Part 63, Subpart B of the Code of Federal Regulations. 3 ------- Proposal June 1993 1.2 Overview of the Regulatory Requirements The owner or operator or a major source is required to apply for a Title V permit, when the promulgation deadline for a relevant Section 112(d) as been missed. The permit application must be received by the permitting agency no later than 18 months from the date that the promulgation deadline was missed. EPA also recommends that an owner or operator of a major source subject to the provisions of Section 112(j) also be required to obtain a Notice of MACT Approval before constructing a new source, or reconstructing an existing source. This recommendation is discussed in greater detail in Section 1.3 of this chapter. In preparing an application for a Title V permit or a Notice of MACT Approval, the owner must recommend a level of control and appropriate monitoring, reporting and recordkeeping parameters for control of HAP emissions from each existing source or new source within the source category. The recommended level of HAP emission control should be based on the maximum achievable control technology (MACT), and be no less stringent than the MACT floor (when information is available to determine the MACT floor level of control.) Chapter 3 of this manual discusses a process for developing the information required in the Title V permit application or application for a Notice of MACT Approval. The process is termed 4 ------- Proposal June 1993 the "MACT analysis". This analysis includes a MACT floor finding, establishing a MACT emission limitation and selecting a control technology to meet this emission limitation. Ideally, State and local agencies will coordinate efforts with other agencies, and with owners or operators of affected major sources to develop a source category equivalent emission limitation before the deadline for permit application submittal. If a State or local agency can provide an owner or operator with all available information, or if the State conducts the MACT analysis, it would not be necessary for an owner or operator to conduct an independent MACT analysis to complete the required application. The information made available from the State or local agency can be used to complete the application. However, failure of any given permitting agency to make information available to an owner or operator or conduct the MACT analysis in advance to the application submittal does not relieve the source of its statutory obligation to submit a permit application; or, if a permitting agency requires it, the obligation to apply for a Notice of MACT approval. Coordination of State efforts is discussed in greater detail in Chapter 2 of this manual. Once the MACT analysis is complete the owner or operator can prepare the Title V permit application or application for a Notice of MACT Approval. The application for a Title V permit should be prepared in accordance with the provisions contained in 40 CFR Part 63 and 40 CFR part 70 or CFR Part 71 whichever is 5 ------- Proposal June 1993 applicable to the major source. The requirements for new sources are also codified in 40 CFR Part 63, Subpart B. Section 1.3 of this chapter describes a recommended process for determining that a new source will meet a new source level of emission control. ------- Proposal June 1993 1.3 Administrative Review Process for New Sources 1.3.1 Application Process Subpart B of 40 CFR Part 63 recommends that the permitting agency require any owner or operator of a major source that is subject to Section 112(j) of the Act undergo a preconstruction review if the major source constructs a new source or reconstructs an existing source and intends to commence construction of this source after 18 months from the missed promulgation deadline. This preconstruction review process would be automatically required if the new source also meets the definition of a constructed, reconstructed or modified major source established under the regulatory provisions for Section 112(g) of the Act, (also contained in 40 CFR Part 63, Subpart B.) Some owners or operators may also be required to obtain a Part 70 or Part 71 revision if a source's existing Title V permit prohibits the construction of a new source or reconstruction of the existing source without first obtaining a permit revision. When a revision to a permit is not specifically required in advance of the major source change, and an owner or operator does not voluntarily revise or obtain the Title V permit before construction, EPA recommends that the permitting agency require that the owner or operator obtain a Notice of MACT approval before commencing construction of the proposed source. The Notice of MACT approval can serve as the mechanism to 7 ------- Proposal June 1993 ensure federal enforceability of the requirements established during the preconstruction review before such requirements are incorporated into the Title V permit. As required by Part 70, the requirements contained in the Notice of MACT approval would be incorporated into the permit within 12 months from the start- up of the source. This would be done through either a significant permit revision or an administrative amendment to the permit. After receiving an application for a MACT determination, the EPA recommends that the permitting agency have 30 calendar days to review the application for completeness. No later than 30 calendar days from the date that an application is received, the reviewing agency should notify the owner or operator in writing that the application is complete or that additional information is required. If the reviewing agency fails to issue a status of completeness notice within the 30 day period, the application could automatically be deemed complete. After a notice of completion is issued, the reviewing agency should have 60 calendar days to issue a preliminary Notice of MACT Approval or disapprove the application. The 60-day period could begin on the date that the notice of completion is issued. Before issuing a final disapproval of an application, the reviewing agency should inform the applicant in writing of the intent and grounds for the disapproval. The applicant should have 30 days from the date of notification to supply additional 8 ------- Proposal June 1993 information, or amendments to the application. If no additional information is received in 30 days, a final disapproval should be issued. If additional information is submitted, the reviewing agency should have 30 additional days to review the information and issue a preliminary Notice of MACT approval or issue a final disapproval of the application. A final disapproval should be in writing and should specify the grounds on which the disapproval was based. In order for the requirements in a Notice of MACT Approval to be federally enforceable, EPA and the public must be provided the opportunity to review the notice before final issuance. EPA recommends that the Notice of MACT Approval undergo a 45 day review period, during which the EPA or the public may comment on the preliminary notice. The final Notice of MACT approval could then be issued after this public review period. Figure 1 provides a suggested format for the Notice of MACT Approval. ------- Proposal June 1993 Figure 1 Example Notice of MACT Approval Notice of MACT Approval CFR 40, Part 63, Subpart B Maximum Achievable Control Technology Emission Limitation for Constructed, Reconstructed or Modified Source This notice establishes federally enforceable maximum achievable control technology emission limitation(s) and requirements for Name of manor source for the MACT-affected emission unit(s) located at location all MACT-affected emission units. The emission limitations and requirements set forth in this document are federally enforceable on effective date of notice. A. Major source information 1. Mailing address of owner or operator: 2. Mailing address for location of manor source; 3. Source category for manor source: 4. MACT-affected emission unit(s): List all emission unit(s) subject to this Notice of MACT Approval along with the source identification number if applicable. 5. Type of modification, construction or reconstruction: Describe the action taken by the owner or operator of the major source that triggered the requirements of 40 CFR Part 63, Subpart B. 6. Anticipated commencement date for construction. reconstruction or modification: 7. Anticipated start-up date of constructed, reconstructed or modified emission unit(s): 8. List of the hazardous air pollutants potentially emitted bv MACT-affected emission unit(s): List all 10 ------- Proposal June 1993 hazardous air pollutants that are or could possibly be emitted from the affected emission unit(s). Any pollutant not listed in this section can not be emitted by the emission unit without an amendment to the Notice of MACT Approval. B. MACT Emission limitation 1. The above stated owner or operator shall not exceed the following emission limitation(s) for the above stated MACT-affected emission unit(s). Write in emission standard or MACT emission limitation for overall hazardous air pollutant emissions from each affected emission unit. If the permitting authority determines that an individual pollutant emission limitation is appropriate, it should also be listed in this section. 2. The above stated owner or operator shall install and operate the following control technology(s), specific design equipment, work practice, operational standard, or combination thereof to meet the emission standard or MACT emission limitation listed in paragraph 1 of this section. List all control technologies to be installed by the owner or operator and which emission units the control technologies will reduce HAP emissions from. 3. The above stated owner or operator shall adhere to the following production or operational parameters for the technologies listed in paragraph 2 of this section. State all production or operational parameters. For example: The owner or operator may, subject to [name of agency] approval, by pass the emission control device for a limited period of time for purposes such as maintenance of the control device. The owner or operator shall operate and maintain the control equipment such that it has a 95% hazardous air pollutant destruction efficiency. The owner or operator shall not operate the MACT- affected emission unit for greater than 6 hours in any 24 hour period of time. C. Monitoring requirements For each MACT emission limitation and operational requirement established in Section B (MACT emission limitation) the above stated owner or operator shall comply 11 ------- Proposal June 1993 with the following monitoring requirements. State all monitoring requirements. For example: After installing the control equipment required to comply with Section(B)(1) visually inspect the internal floating roof, the primary seal, and the secondary seal, before filling the storage vessel The owner or operator shall calibrate, maintain and operate a continuous monitoring system for the measurement of opacity of emissions discharged from the control device required in Section(B)(2) according to the following procedures: D. Reporting and Recordkeeping Requirements List all reporting and recordkeeping requirements in this section. For example: The owner or operator shall maintain at the source for a period of at least 5 years records of the visual inspections, maintenance and repairs performed on each secondary hood system as required in Section(B)(2). E. Other requirements 1. The above stated owner or operator shall comply with all applicable requirements specified in the general provisions set forth in Subpart A of 40 CFR Part 63, including but not limited to notification operation and maintenance, performance testing, monitoring, reporting, and recordkeeping requirements. If there are any specific requirements that the reviewing agency would like to clarify, those requirements should also be stated in this paragraph. This paragraph could also include requirements for emergency provisions and start-up and shut-down procedures. 2. In addition to the requirements stated in paragraph 1 of this section, the owner or operator will be subject to these additional requirements. Any additional requirements not specified in Subpart A of 40 CFR Part 63 should be stated in this paragraph. If the reviewing agency wishes to require a mandatory retest of a failed performance test that should be stated in this paragraph, along with any other requirements specified by the reviewing agency. F. Compliance Certifications 12 ------- Proposal June 1993 The above stated owner or operator shall certify compliance with the terms and conditions of this notice according to the following procedures: This sections should include a description of the terms and condition that the owner or operator will use to certify compliance, as well as, the format and frequency of the certification. 13 ------- Proposal June 1993 1.3.2 Contents of Application: After the owner or operator has determined a MACT emission limitation and selected the MACT, the owner or operator should prepare an application for a Title V permit or Notice of MACT Approval. There is no standard Federal form for the application; however, individual States may develop there own application forms. All applications for a MACT determination should contain the following information: (a) The applicant's name and address; (b) A brief description of the major source, its source category or subcategory, and a description of the affected emission units; (b) A notification of intention and date to construct, reconstruct, or modify; (c) The address (physical location) of the affected emission unit; (d) The expected commencement date of construction, reconstruction, or modification; (e) The expected completion date of construction, reconstruction, or modification; (f) The anticipated date of start-up; (g) A list of HAPs emitted by the emission unit and rate of emission; 14 ------- Proposal June 1993 (h) The uncontrolled emissions for the emission unit; (i) A description of the MACT including technical information on the design, operation, size, estimated control efficiency, etc.; (j) Supporting documentation such as a the costs, non air quality health and environmental impacts and energy requirements analysis; (k) Controlled emissions for the emission unit; (1) Any federally enforceable limits already imposed on the affected emission unit; (n) Other information which may be required pursuant to 40 CFR Part 63, Subpart A 15 ------- Proposal June 1993 Chapter 2.0 The MACT Determination... a Permitting Agency's Perspective 2.1 Criteria for the MACT Determination The process of reviewing the Title V permit application or the application for a Notice of MACT Approval to determine an equivalent (MACT) emission limitation is called a MACT determination. For MACT determinations under Section 112(j), the MACT emission limitation should be comparable to the emission limitation(s) or requirements that would likely be imposed if a Section 112(d) or Section 112(h) emission standard had been promulgated for that source category. The Clean Air Act sets forth specific criteria for setting a hazardous air pollutant emission standard under Sections 112(d) and Section 112(h). These criteria should also be used when establishing the MACT emission limitation under Section 112(j). In conducting the MACT determination, the permitting agency must determine if the owner or operator has recommended an appropriate MACT emission limitation(s) or other requirements for the MACT-affected emission unit, given the expected performance of the maximum achievable control technology (MACT). When conducting a MACT determination, the permitting agency should evaluate the application to determine if the recommended MACT emission limitation, and the suggested control technology meet 16 ------- Proposal June 1993 the following criteria: (a) When a relevant emission standard has been proposed pursuant to Section 112(d) or 112(h) of the Act, the MACT emission limitation and control technology selected by the owner or operator achieves all emission limitations and requirements of the proposed standard. (b) When a relevant emission standard has not be promulgated or proposed pursuant to Section 112(d) or Section 112(h): (1) The owner or operator documents a MACT floor finding based on all available information, and (2) When a positive MACT floor finding is made, the application recommends a MACT emission limitation and selects a control technology that is at least equal to the MACT floor and achieves the maximum degree of emission reduction of the hazardous air pollutants with consideration to the costs,, non- air quality health and environmental impacts and energy requirements associated with the emission reduction; or, (3) When a negative MACT floor finding is made, the owner or operator recommends a MACT emission limitation and control technology to meet this limitation with consideration to costs, non-air quality health and environmental impacts, and 17 ------- Proposal June 1993 energy requirements after evaluating all control technologies that can be identified through available information and that have been successfully demonstrate in practice for a similar source; and, (4) When a MACT emission limitation can not be prescribes due to the nature of the process or pollutant, the owner or operator designates a specific design, equipment, work practice, operational standard, or a combination thereof, that achieves a maximum degree of emission reduction. The MACT floor finding is a determination of whether a level of HAP emission control that is equal to the MACT floor can be determined using available information. The MACT floor finding is discussed further in Section 3.6 of Chapter 3. The definition of available information is discussed in Section 2.3 of this Chapter. The MACT emission limitation could be expressed as a numerical emission limitation on the total quantity of HAP emissions from the source in tons per year (tpy); or, it could be expressed as unit per production ratio. The MACT emission limitation could also be a performance standard based on the expected efficiency of MACT in reducing HAP emissions. If it is infeasible to prescribe a specific numerical limitation or 18 ------- Proposal June 1993 reduction efficiency the MACT emission limitation can also be expressed based on a design, equipment, work practice, operational standard, or any combination of these. If an individual hazardous air pollutant is of particular concern, a MACT limitation should also be placed on that pollutant based on the expected level of reduction with MACT in place. Reviewing agencies have discretionary authority to impose an individual MACT emission limitation on a specific hazardous air pollutant. In addition to recommending the MACT emission limitation, the reviewing agency should specify any requirements that are necessary in order to make the emission limitation federally enforceable as a legal and practical matter. This involves establishing appropriate operational or production limits and monitoring parameters to ensure compliance with the MACT emission limitation. The following section discusses compliance provisions in greater detail. 19 ------- Proposal June 1993 2.2 Compliance Provisions Each Title V permit and Notice of MACT approval must contain sufficient testing, monitoring, reporting, and recordkeeping requirements to ensure that the MACT emission limitation is federally enforceable as a legal and practical matter. In order to be federally enforceable, operational limits or production limits must be imposed on the source in addition to a blanket emission limitation. For example, a blanket 40 tpy MACT emission limitation on HAPs would not be federally enforceable. In addition to the blanket emission limitation, a source may be required to comply with a production limitation that limits the amount of gallons used per hour in the operation; or the source may be required to comply with an operational limitation on its hours of operation and emission rate, that when multiplied together can result in emissions from the source that do not exceed 40 tpy. Production limits are restrictions on the amount of final product which can be manufacture or otherwise produced at the source. Operation limitations are other restrictions on the manner in which a source is run. Operation limitations include limits on quantities of raw material consumed, fuel combusted, hours of operation, or conditions which specify that the source must install and maintain controls that reduce emissions to a specified emission rate or level. When the permit or Notice of MACT Approval requires an add- 20 ------- Proposal June 1993 on control, operating parameters and assumptions that can be used to determine the efficiency or emission rate of the devise should be specified in the document. For example, a source may have a MACT emission limitation that requires a control devise to be installed and operated at a 95% efficiency rate. An operational limit on the range of temperatures that the devise can be operated under could be sufficient to ensure federal enforceability, if operating the control devise within this temperature range ensures that the devise achieves a 95% destruction efficiency. If establishing operating parameters for control equipment is infeasible in a particular situation, a short term emission limit (e.g. Ibs/hr) would be sufficient provided that such limits reflect the operation of the control equipment, and additional requirements are imposed to install, maintain, and operate a continuous emission monitoring system (GEM). A Title V permit or Notice of MACT Approval should also specify that CEM data may be used to determine compliance with the MACT emission limitation. If parameter monitoring of a production or operational limit is infeasible due to the wide variety of coatings or products used or the unpredictable nature of the operation, emission limits coupled with a requirement to calculate daily emissions may be required. For instance, a source could be required to keep the records of the daily emission calculation, including daily quantities and the HAP content of each coating used. 21 ------- Proposal June 1993 For either operation or production limitations to be enforceable as a practical matter, the limitations should extend over the shortest practicable time period, generally not to exceed one month. If it is not practicable to place a monthly limit on the source, a longer time can be used with a rolling average period. However, the limit should not exceed an annual limit rolled on a monthly basis. In addition to conveying practical enforceability of a MACT emission limitation, the Title V permit or Notice of MACT Approval should require testing or instrumental or noninstrumental monitoring that yields data this is representative of the source's operations and can be used to certify the source's compliance with the terms and conditions of the Title V permit or Notice of MACT Approval. Such testing or monitoring requirements may be in the form of continuous emission monitoring systems, continuous opacity monitoring systems, periodic testing, or it may consist of recordkeeping designed to serve as monitoring. If periodic testing is required, the specific EPA approved method or equivalent method that is to be used should be specified in the permit or notice. 22 ------- Proposal June 1993 2.3 Available Control Technologies Section 112(j) states that permits issued pursuant to Section 112(j) shall contain an equivalent emission limitation. This emission limitation is to be "equivalent" to that which the source would have been subject to if an applicable Section 112(d) or Section 112(h) emission standard had been promulgated. In order to establish an emission limitation that would be equivalent, the permitting agency must determine the equivalent emission limitation with consideration to the MACT floor using available or reasonably available emissions information. For the purposes of a Section 112(j) MACT determination, emission information is considered available or reasonably obtainable to the permitting agency if the information can be obtained from EPA's Office of Air Quality, Planning and Standards, the EPA's National MACT database or other publically available databases (See Chapter 5), from State or local agencies or within the permitting agency itself. A permitting authority is not required to obtain additional information from databases or other State and local agencies if the information used to propose a Section 112(d) or Section 112(h) standard is used to establish the MACT floor. It is not necessary for the MACT floor to be determined based on emissions information from every existing source in the source category if such information is not available. Once a permitting agency has obtained available information, the MACT 23 ------- Proposal June 1993 floor can be determine using this information if it is representative of the source category. EPA realizes that the information that is reasonably available or obtainable for the permitting agency is not necessarily reasonably available to the owner or operator. Owner's or operator should submit an application for Title V permit or a Notice of MACT Approval based on information that the owner or operator is able to obtain. The permitting agency should use the completeness of application review period to determine if the owner or operator should consider additional information that is reasonably available to the permitting authority. An amended application should be submitted if additional information should be consider in the MACT analysis. Once the application is deemed complete, additional information that comes available does not need to be considered before issuing the Title V permit, or Notice of MACT Approval if the information was not reasonably available at the time of the completeness determination. 24 ------- Proposal June 1993 2.4 Approaches to the MACT determination Section 112(j) states that permits issued pursuant to Section 112(j) shall contain an equivalent emission limitation. This equivalent emission limitation is to be determined on a case-by-case basis. The EPA views the case-by-case determination required under Section 112(j) and that required under Section 112(g) (modification, construction and reconstruction provisions) to be fundamentally different. While Section 112(g) would require a case-by-case determination for each source, EPA views the determination under Section 112(j) to be a case-by-case determination for each source category, or a "source category-by- source category" determination. EPA would like to see a consistent approach in defining the boundaries of the existing source and new source, and defining the level of control required for all sources in the source category. Several different approaches to the MACT determination process could be taken by a permitting agency. An agency could wait until all applications for permits are received to determine the equivalent emission limitations that would apply to all the sources. Or, an agency or a group of agencies could conduct a "MACT analysis" based on available information before the deadline for application submittal. The first approach requires less upfront coordination on the part of the permitting agency. While a permitting agency is not legally bound to conduct an information search before reviewing 25 ------- Proposal June 1993 the permit applications, the permitting authority will need to assure that all available information has been considered in evaluating the application. If a permitting agency chooses to wait until an application is received to determine the extent of information that is available, several permit applications may need to be revised to reflect information identified by the agency. Also, under this approach each application will need to undergo public review. The implications of this are that there may be less consistency in the source category by source category equivalent emission limitation for each major source. While this may be unavoidable when each permit is reviewed on an individual basis, a permitting agency may need to justify any discrepancies between the level of control required for existing sources within the same source category. The second approach would allow a permitting agency to convey information to an applicant in advance of the application submittal. A permitting agency could conduct an information search to determine the available information, or a "coalition" of permitting agencies could be formed to facilitate the information exchange. Once the available information is identified the permitting agency could conduct a MACT analysis (See Chapter 3) to determine the appropriate level of control for each source. The control level could be established through a State regulation or general permit. The following section of this chapter discusses the concept of general permits in greater 26 ------- Proposal June 1993 detail. If a permitting agency is unable to establish the level of control through a State regulation or general permit, the available information could be used for information exchange with each permit applicant. This would assure greater consistency in control levels recommended by the applicants. 27 ------- Proposal June 1993 2.4 General Permits A general permit is a type of Title V permit. A single general permit could be issued by a permitting authority to cover a number of sources. The specific requirements for a general permit are contained in 40 CFR Part 70.6(d). The general permit can be written to set forth requirements for an entire source category, or portion of the source category. The facilities that are covered by the general permit, should be homogenous in terms of operations, processes, and emissions. In addition, the facilities should have essentially similar operations or processes and emit pollutants with similar characteristics. The facility should be subject to the same or substantially similar requirements governing operations, emissions monitoring, reporting, or recordkeeping. Because the case-by-case determination under Section 112(j) is a source category-by-source category determination of an equivalent emission limitation, the permitting agency could use the general permit as a mechanism to issue Title V permits to the entire source category, or specific emission units within the source category. By using this mechanism, a permitting agency would not be required to issue individual permits to sources covered by the general permit. Also, once the general permit has been issued and after opportunity for public participation, EPA review and affected State review, the permitting authority may grant or deny a source's request to be covered by a general 28 ------- Proposal June 1993 permit without further outside review. Major sources that do not require a specific Title V permit for any other reason, could be covered by the general permit indefinitely. For a major source that already has a Title V permit, the owner or operator can apply for coverage under the general permit, and then incorporate the general permit requirements into the source specific permit through an administrative amendment at permit renewal. 29 ------- Proposal June 1993 Chapter 3 The MACT Analysis For most source categories, the process of recommending a level of control involves a number of decisions either on the part of the owner or operator preparing an application for a Title V permit or Notice of MACT Approval, or a permitting agency who is conducting a MACT determination. First, the source category boundaries must be defined. All points within this boundary that emit one or more hazardous air pollutants are subject to control through an eguivalent emission limitation and must be addressed in the permit application(s). Within this source category boundary there may be one or more existing sources (stationary sources) for which an equivalent emission limitation will be established. The existing source boundary may be synonymous with the source category boundary, or a single source category may contain several existing sources. For each existing source, the MACT floor level of control must be determined. The application submitted by an owner or operator must recommend an equivalent MACT emission limitation that is no less stringent than the MACT floor, but could be more stringent if a greater degree of HAP emission reductions can be achieved with consideration to the costs, non-air quality health and environmental impacts and energy requirements associated with 30 ------- Proposal June 1993 achieving the additional emission reductions. The process by which these decisions are made have been termed the MACT analysis. The following sections of this Chapter describe a MACT analysis process that EPA has developed to meet the requirements of 40 CFR Part 63, Subpart B as described in Section 2.1 of Chapter 2. 3.1 Overview of the MACT Analysis Process Along with determining the existing or new source boundaries, the MACT analysis uses available information to make a MACT floor finding. There are several possible situations that may arise in the course of conducting a MACT analysis. First, the MACT floor could be determined, and control technologies that meet the MACT floor requirement could be identified. This is known as a positive MACT floor finding. Another possible outcome is that the MACT floor equals "no control". The third possible outcome is that the MACT floor can not be determined. This could be due to the nature of the pollutants emitted from the source, the lack of available data, or because there are less than five sources in the source category. In these cases, a negative MACT floor finding is made. Because of the variety of situations that could arise, the MACT analysis has been divided into three tiers. Figure 2 diagrams the steps for Tier I, Tier II and Tier III of the analysis. If a positive MACT floor finding is made, the owner or 31 ------- Figure 2 The MACT Analysis Tier I -- Making a MACT Floor Finding 1) Identify the MACT-affected emission unit. 2) Make a MACT floor finding: f i if ' "i positive ' if negative J 4) Identify MACT I Tier II - Considering All Control Technologies 1)- List all available control technologies. 2) Eliminate technically infeasible control options. 3) Conduct a costs, non-air quality health and environmental impacts, and energy requirements analysis. 4) Identify MACT I Tier -- Establishing a MACT Emission Limitation 1) Establish the MACT emission limitation (MEL). 2) Select a control technology to meet MEL. 3) Establish monitoring, reporting and recordkeeping parameters. 4) Submit application. . ------- Proposal June 1993 operator or a permitting agency is only required to complete Tier I and Tier III of the MACT analysis. This analysis allows the owner or operator or a permitting agency to compare the costs, non-air quality health and environmental impacts and energy requirements associated with using control technologies that obtain a level of HAP emission reductions that is equal to or greater than the MACT floor. If the MACT floor can not be determined or is equal to "no control" (a negative MACT floor finding), the owner or operator is also required to complete Tier II of the analysis. All MACT analyses should begin with Tier I. During this Tier, the owner or operator or the permitting agency will identify the emission points subject to a MACT determination, (the MACT-affected emission unit,) determine the existing emission unit or new emission unit boundaries, and make a MACT floor finding for each emission unit (the MACT-affected emission unit.) The owner or operator or the permitting agency can make a MACT floor finding by using available emissions information to determine if: (1) a specific MACT floor level of control can be calculated; (2) the very best control technology can be identified; or, (3) there is a previous case-by-case MACT determination for a source within that source category. The procedures detailed Chapter 4 explain several acceptable methods for determining a MACT floor level of control. If a negative MACT floor finding is made the owner or 33 ------- Proposal June 1993 operator would move to Tier II of the MACT analysis. The purpose of Tier II is to identify all control technologies using available information, including work practices, and pollution prevention methods that could reasonably be applied to the emission unit subject to the MACT determination. Available control technologies include but are not limited to: reducing the volume of, or eliminating emissions of pollutants through process changes, substitution of materials or other techniques; enclosing systems or processes to eliminate emissions; collecting, capturing, or treating pollutants when released from a process, stack, storage or fugitive emission point; using designs, equipment, work practices, or operational standards (including requirements for operator training or certification); or, a combination of any of these methods. Strategies for identifying available control technologies are discussed later in this chapter. Once a list of available control technologies has been developed, each control technology should be evaluated to consider the costs, non-air quality health and environment impacts, and energy requirements associated with using each control technology. The control technology(s) achieving the maximum degree of HAP emission reductions taking into consideration the costs of achieving such emission reductions and the non-air quality health and environmental impacts and energy requirements should be selected as MACT. Once MACT has been 34 ------- Proposal June 1993 selected through either Tier I or Tier II of the analysis, the owner or operator should move to Tier III. In Tier III, a MACT emission limitation(s) should be established based on the degree of emission reductions that can be achieved through the application of the maximum achievable control technology (MACT); or, a design, equipment, work practice or operational standard, or combination there of, should be designated if it is infeasible in the judgement of the permitting agency to prescribe or enforce a specific MACT emission limitation based on MACT. The owner or operator or the permitting agency should also suggest conditions and appropriate monitoring parameters to make this emission limitation federally enforceable. Once the owner or operator has made a MACT floor finding, established a MACT emission limitation, and selected a control technology to meet this limitation, the owner and operator should apply for a Title V permit, or Notice of MACT Approval in accordance with the procedures contained in 40 CFR Part 63, Subpart B and 40 CFR Part 70. 35 ------- Proposal June 1993 3.2 A Detailed Look at the MACT Analysis Tier I - Making a MACT floor finding Step 1 ~ Identify the MACT-affected emission unit(s) In accordance with the provisions established in 40 CFR Part 63, Subpart B, the owner or operator is required to identify all emission points emitting one or more HAPs within the source category boundary. These "affected emission points" will be grouped into emission units (MACT-affected emission units). Each of these emission units will be subject to a MACT determination. When a relevant emission standard has been proposed, the application should reflect boundaries for the MACT-affected emission unit that are consistent with the existing source boundaries, affected emission points, or other portion of the major source identified by the proposed emission standard. When no relevant emission standard has been proposed, the MACT- affected emission unit will be determined on a case-by-case basis. Section 3.3 of this chapter discusses principles for determining the MACT-affected emission unit on a case-by-case basis. Step 2 — Make a MACT floor finding The owner or operator will need to determine if there is enough information available about other emission units to calculate a level of HAP emission control that is equal to the 36 ------- Proposal June 1993 MACT floor for each type of emission unit undergoing review. For new or reconstructed sources, the MACT floor (or best controlled similar source) should be determined using emissions information on similar emission units from within and outside of the source category. (Section 3.4 clarifies the term similar emission unit.) For existing emission units, the MACT floor should be calculated using only emissions information on other emission units within the source category. An owner or operator can avoid calculating a specific emission control level that is egual to the MACT floor, while still making a positive MACT floor finding by selecting the very best control technology. The owner of operator is referred to existing EPA control technology guideline documents (CTG) and background information documents (BID). These document may help identify best control strategies for the control of HAPs from a given type of emission unit. An owner or operator could also develop a list of available control technologies (similar to that which would be developed under a Tier II analysis) and establish a MACT emission limitation based on the control technology that achieves a maximum reduction in hazardous air pollutant emissions with consideration to the costs of achieving the emission reductions, and the non-air quality health and environmental impacts, and energy requirements. However, minimal consideration should be given to cost in such an analysis. If an owner or operator chooses not to, or is unable to identify a MACT floor 37 ------- Proposal June 1993 level of control by using any of these methods, the owner or operator will be required to review all available emissions information to determine if a specific MACT floor level of control can be found. The easiest method for determining a specific MACT floor level of control is to rely on a previous MACT determination that was made for a similar emission unit within the source category. A previous MACT determination could have been made for a similar emission unit due to a construction, reconstruction or modification according to the provisions of Section 112(g). The owner or operator is referred to any existing Federal, State or local data bases as well as the public record to determine if a MACT determination for a similar emission unit has recently been made. This MACT determination can be used to establish the MACT floor, a MACT emission limitation, and select a control technology as long as there is no reason to believe that the MACT floor may have changed since the effective date of that determination. Reasons to believe that the MACT floor may have changed would include, but are not limited to, the passing of a State regulation in a particular State that specifically regulates that type of emission unit. And, the close down or start up of a number of major sources within the source category. If no previous MACT determination has been made, or the owner or operator would like to calculate a more current MACT floor, the owner and operator can use emissions information that 38 ------- Proposal June 1993 is available for other emission units within the source category. The degree of emission reductions can be calculated by referring to existing State and local regulations, or by computing a control efficiency rating or emission reductions ratio. All of these methods are detailed in Chapter 4. If the MACT floor can not be determined or it is equal to "no control", a negative MACT finding has been made. Under these circumstances the owner or operator should discontinue Tier I of the analysis and begin with Tier II as later outlined in this section of this chapter. Step 4 — Identifying MACT When a positive MACT floor finding is made, the owner or operator will need to identify control technologies that reduce HAP emissions from the MACT-affected emission unit to the maximum extent and to a level that is at least equal to the MACT floor. The control technology that achieves the maximum degree of HAP emission reductions with consideration to costs, non-air quality health and environmental impacts, and energy requirements is MACT. A permitting agency has discretion to determine the weight that will be given to each one of these factors in identifying MACT. In doing so, a control technology that exceeds the degree of emission reductions that is equal to the MACT floor may be identified as MACT. Under no circumstances should MACT be less stringent than the MACT floor. 39 ------- Proposal June 1993 In general, a control option that reduces overall HAP emissions to the greatest extent should be identified as MACT; however, there may be occasions when the hazard to human health and the environment of a particular HAP warrants the selection of a MACT specifically for the control of that HAP. Identification of more than one control technology may be necessary when an emission unit has multiple HAP emissions. An owner or operator is advised to consult with the reviewing agency to determine if this is the case. After this step is completed an owner or operator should skip to Tier III of the analysis. Tier II - Considering all control technology Step 1 — List available control technologies Using available information, the owner or operator or permitting agency should develop a list of control technologies that have been successfully demonstrated in practice for similar emission units. Similar emission units are discussed in more detail in Section 3.4 of this chapter. In addition, the owner or operator may wish to consider innovative technologies and transfer technologies that might reasonably be applied to the MACT-affected emission unit. 40 ------- Proposal June 1993 Step 2 — Eliminate technically infeasible control technologies All control technologies that could not be applied to the MACT-affected emission unit because of technical infeasibility should be eliminate from the list. An owner or operator should be prepared to justify the elimination of a control technology in the application for a MACT determination. Step 3 — Conduct a costs, non-air quality health and environmental impacts, and energy requirements analysis The owner or operator or the permitting agency should conduct a detailed analysis on all of the available control technologies. The efficiency of each control technology in reducing overall HAP emissions should be determined. A reviewing agency may require an owner or operator to select MACT based on the degree of emission reductions achieved for one or more specific HAPs when the risk to human health and the environment warrants establishing MACT emission limitations specifically for these HAPs. Otherwise, MACT should be selected based on an overall reduction of all HAP emissions. It should be noted that the application of more than one control technology may be necessary in order to address multiple HAP emissions. After determining the control efficiency of each available control technology, the owner or operator should identify the control technology(s) that allows for a maximum degree of HAP emission reductions with consideration to the costs of achieving 41 ------- Proposal June 1993 such emission reductions, and the non-air quality health and environmental impacts and energy requirements. This is the MACT. See Chapter 3 of this guidance document for a more detailed discussion of the costs, non-air quality health and environmental impacts, and energy requirements analysis. Tier III — Establishing a MACT emission limitation Step 1 — Establish a MACT emission limitation (MEL) The owner or operator should determine the degree of emission reduction that can be obtained from the MACT-affected emission unit, if MACT is applied, and properly operated and maintained. The MACT emission limitation should be based on an overall reduction of all HAP emissions; however, if possible, the efficiency of the MACT in reducing each potential HAP emission should also be stated. The permitting agency will also have the discretion to establish a MACT emission limitation for an individual HAP when the risk to human health and the environment warrants such an emission limitation, or when such a limitation is necessary to make the overall HAP emission limitation federally enforceable. Chapter 4 discusses three ways to establish a MACT floor: 42 ------- Proposal June 1993 using State and local regulations, control efficiencies and emission reduction ratios. If State and local regulations are used to establish the MACT floor, the MACT emission limitation may be based on a specific emission limitation contained in a regulation such as 10 Ibs/per gallon of coating applied. In other cases, the regulations may be based on a specific design or work practice. It may not be feasible to establish a specific numerical or efficiency limitation, in such cases. If it is infeasible to prescribe a specific emission limitation, The MACT emission limitation should be based on the application of a specific design, process, or control technology. When control efficiencies are used to establish a MACT floor, the MACT emission limitation (MEL) can be computed by multiplying the efficiency of MACT by the uncontrolled emission level (UCEL) of the emission unit as follows: MEL = UCEL * MACT efficiency The reader should refer to Section 4.4 for a definition of uncontrolled emission level. When the emission reduction ratio is used to determine the MACT floor, the MACT emission limitation can be computed by multiplying the uncontrolled emission level by the emission reduction ratio of MACT using the following formula: MEL = UCEL * (1 - 43 ------- Proposal June 1993 Step 2 — Select a control technology to meet the MACT emission limitation Once the MACT emission limitation is established, the owner or operator should determine the control technology that should be applied to the emission unit that will allow the source to meet the required MACT emission limitation. In many cases, this will be the MACT technology. However, in some cases, the emission unit may already be controlled to a some extent with an existing control devise. The owner or operator could demonstrate that using additional control strategies in combination with existing controls will allow the emission unit to achieve the required emission reductions. For instance, an emission unit may currently be controlled with a baghouse. MACT for the emission unit may be an electric static precipitator. The emission unit may be able to meet the MACT emission limitation by installing a series of baghouses in lieu of the electric static precipitator. The amount of additional control required (ARC) can be computed by subtracting the MACT emission limitation from the controlled emission level (CEL) (See Section 4.4 for the definition of CEL) as follows: ARC = CEL - MEL If ARC is equal to zero or is a negative number, no additional 44 ------- Proposal June 1993 control is required. The emission unit is currently meeting the criteria for MACT. If ARC is a positive number, the owner or operator must reduce hazardous emissions by this amount. The reader is referred to Section 4.4 for a definition of controlled emission level. Owners or operators are reminded that the application of a case-by-case MACT to an emission unit does not exempt that owner or operator from complying with any future emission standards affecting that emission unit. The MACT floor emission limitation as calculated on a case-by-case basis should be considered only a relative indicator of the future MACT emission standard. Changes in technology or application of controls to under-controlled sources may shift the MACT floor to a higher control level, additional emissions information may be available that generates a different level of control for the MACT floor, or a control technology that is more effective in controlling HAP emissions may be selected based on the relative cost of applying that technology on a nationwide basis. Owners or operators may wish to consider applying control strategies that exceed the MACT floor requirement. Step 3 — Establish appropriate monitoring, reporting and recordkeeping parameters The owner or operator or the permitting agency should 45 ------- Proposal June 1993 identify monitoring parameters to assure compliance with the MACT emission limitation. Section 2.2 of Chapter 2 discusses compliance provisions in greater detail. Step 4 — Prepare application for a Title V permit or Notice of MACT Approval Once a control technology(s) is identified and the MACT emission limitation(s) is established, the owner or operator should prepare an application for a Title V permit or Notice of MACT Approval consistent with the procedures contained in 40 CFR Part 63, Subpart B. 46 ------- Proposal June 1993 3.3 Determining the MACT-affected emission unit The purpose of a case-by-case MACT determination is to determine that all affected emission points will meet a MACT emission limitation. A MACT emission limitation will be established for an emission unit known as the MACT-affected emission unit. The MACT-affected emission unit could either be a single affected emission point, or a combination of affected emission points. There are four basic principles to follow when designating the MACT-affected emission unit. The principles can be summarized as follows: 1) When a relevant Section 112(d) or Section 112(h) standard has been proposed, the owner or operator and the permitting agency should refer to the relevant standard to determine the MACT-affected emission unit; or, (2) When a source category on the source category list is designated as a specific piece of equipment, the MACT-affected emission unit is that piece of equipment or apparatus; or, (3) The EPA's Office of Air Quality Planning and Standard's should be consulted to determine if a suggested method for grouping of affected emission points is available; or, (4) Emission points should be combined into a single MACT-affected emission unit when the combination of points leads to a much more cost-effective method of control, and achieves a greater degree of emission reductions when compared to point-by-point compliance. The best indicator of how a source category may be regulated 47 ------- Proposal June 1993 after the promulgation of a relevant standard is found in a proposed standard. For this reason, EPA believes that owners or operators and permitting agencies should follow the guidelines in the proposed standard for determining the MACT-affected emission unit for a Section 112(j) MACT determination. Although there may be no proposed standard for the source category, and EPA may have missed the promulgation deadline for that source category, information on the source category may have been collected which allows EPA to recommend a specific method for determining the emission unit for a Section 112(j) MACT determination. Therefore, EPA should be consulted before attempts are made to define the MACT-affected emission unit on a case-by-case basis. EPA can be contacted through the Control Technology Center Hotline operated by the Office of Air Quality Planning and Standards at (919)-541-0800. When an affected emission point(s) is associated with a piece of equipment or apparatus specifically listed on the source category list, that affected emission point(s) is the MACT- af fected emission unit. The source category list (See Appendix D) contains sources that are defined by a manufacturing or process operation, or as an individual piece of equipment. In developing the source category list, EPA determined that some individual pieces of equipment have the potential to emit major amounts. For example, under the fuel combustion industrial grouping, stationary internal combustion engines are listed as a 48 ------- Proposal June 1993 source category of major sources. When a source category is designated by a single type of apparatus, the EPA believes that the intent is for emission limitations and requirements to be placed on that specific piece of equipment. As such, if a Section 112(j) determination is conducted for any one of these source categories, the specific piece of equipment or apparatus should be designated as the MACT-affected emission unit. Other examples of apparatus that are listed as a source category or major sources are municipal waste incinerators, process heaters, and stationary turbines. The owner or operator should review the list found in Appendix D to determine other source categories that could be defined as the MACT-affected emission unit. Otherwise, individual affected emission point can be considered a MACT-affected emission unit, or a group of affected emission points can be combined into one affected emission unit. There are several ways in which emission points could be combined to form an emission unit. A few points could be combined, an entire process unit could be included in the MACT-affected source, or the MACT-affected source could be as large as the source category boundary. For example, a single emission point such as a storage tank could be consider the MACT-affected emission unit. Or, emission points from a distillation column, a condenser and distillate receiver could be consolidated into one emission unit. Larger groupings of emission points maybe appropriate when a single 49 ------- Proposal June 1993 control technology can be used to control the aggregation or when a pollution prevention or waste reduction strategy is considered. For instance, the entire wastewater treatment operation could be considered one emission unit. Collectively, a single steam- stripper could be used at the beginning of the operation to remove HAPs from the wastewater and prevent downstream emissions from occurring. Another example is illustrated with a surface coating operation. Rather than individually controlling the emissions from a spray booth, flash-off area, and bake oven, switching to a water-based paint could reduce emissions from all of these emission points. Another reason to combine affected emission points into a single emission unit is that many major sources are already subject to regulation under 40 CFR Part 60 and Part 61. In promulgating these standards, "affected facility" definitions were developed to designate the apparatus to which a standard applies. It may make sense to use these same boundaries to designate the "MACT-affected emission unit" subject to a MACT determination. It should be noted that a particular piece of apparatus or equipment should not be excluded from a MACT determination because of an applicability "cut-off" established under a Part 60 or Part 61 regulation. Emission points could be consolidated into an emission unit that is as large as the source category boundary for several reasons. First, the MACT floor needs to be calculated 50 ------- Proposal June 1993 specifically for the MACT-affected emission unit. The information that is available to calculate the MACT floor may only be available for the source category as a whole, not individual points within the category. Also, the operations of some source categories are quite variable. Either the nature of the process requires a large latitude of flexibility in establishing the emission unit that should be controlled, or the types of facilities within the category are so diverse that it only makes sense to compare the existing sources on a source category wide level. In these instances, a source category wide MACT-affected emission unit could allow some emission points to be under controlled while others are controlled to a level that would exceed the level of control that would be placed on that individual point through the application of MACT. Permitting agencies are cautioned that it would be generally inappropriate to include emission points associated with equipment leak emissions into such a MACT-affected emission unit. There are some situations which would not make the combination of emission points reasonable. First, the combined emission unit can not generate an emission unit that is so unique that it precludes comparing the emission unit to other sources in the source category. Second, the combining of emission points should reduce emissions from all of the affected emission points within the MACT-affected emission unit through use of a control technology that affects all of those emission point, or involves 51 ------- Proposal June 1993 recycling or reuse, or constitutes an overall source reduction strategy as defined in the Pollution Prevention Act, P.L. 101- 503. The types of activities that would be considered pollution prevention or source reduction measures include changes in technology, process or procedures, reformulation or redesign of products, and substitution of raw materials. A decrease in production rate alone would not constitute a source reduction strategy unless the rate reduction was associated with a pollution prevention measure such as increasing efficiency of the operation. Determining the MACT-affected emission unit on a case-by- case basis is a complex undertaken. While this document includes this step as a separate component of the Tier I approach, in actual practice the identification of methods to control specific groups of emission units will be an integrated process with the identification of control technology options. Some aggregations of emission points may be inappropriate because the information available to calculate the MACT floor would dictate combining emission points into certain emission units, or because controls applied to the unit would not achieve a MACT level of control when compared to point-by-point compliance or some other combination of emission units. Appendix A provides an example of ways in which available control technologies would affect the aggregation of emission points into an emission unit. 52 ------- Proposal June 1993 3.4 Similar Emission Units When an owner or operator constructs or reconstructs an emission unit a MACT emission limitation(s) must be meet based on a new source level of control. This emission limitation should be based on the emission reductions achieved by the best controlled similar source. Also, when a MACT floor can not be determined for an existing emission unit during Tier I of the MACT analysis, the owner or operator is required to identify all available control technologies, using available information, that could be applied to a similar emission unit. For the purposes of case-by-case MACT determinations under Section 112(j), a similar source is a similar emission unit. If two emission units have similar emission types and could be controlled using the same type of control technology, those emission units would be considered similar for the purposes of a case-by-case MACT determination. For instance, plastic extrusion is used in both the plastic manufacturing industry and graphic art industry. The emissions from these industries may be similar and be amendable to the same type of control technology. The EPA developed an emission classification system to be used for determining emission types for case-by-case MACT determination. The five emission classifications are as follows: 53 ------- Proposal June 1993 Process vent or stack discharges - the direct or indirect discharge of an organic liquid, gas, fume, or particulate by mechanical or process-related means. Examples would be emission discharges from columns and receiving tanks from distillation, fractionation, thin-film evaporation, solvent extraction, air and steam stripping operations, absorbers, condensers, incinerators, flares, and closed-looped biological treatment units. Equipment leaks - fugitive emissions from the following types of equipment: valves, pumps, compressors, pressure relief devices, sampling connection systems, open-ended valves and lines, flanges, agitators, sampling connection systems, and valve connectors. Evaporation and breathing losses - emissions from storage or accumulation of product or waste material; for example: stationary and mobile tanks, containers, landfills, and surface impoundments, and pilings of material or waste. Transfer losses - emission of an organic liquid, gas, fume, vapor or particulate resulting from the agitation of material during transfer of the material from one unit to another. Examples of such activities are filling of mobile 54 ------- Proposal June 1993 tanks, dumping of coke into coke quench cars, transfer of coal from bunker into larry car, emptying of baghouse hoppers, and sludge transfer. Operational losses - emissions resulting from the process operation which would result in fugitive emissions if uncontrolled by hoods or vacuum vent, or other vent systems. Examples of operation loses are emission resulting from spray coating booths, dip-coating tanks, quenching towers, lubricating stations, flash-off areas, or grinding and crushing operations. The classification scheme has been developed to serve as a general guide in identifying available control options. When using the list of classifications, consideration should be given to the concentration and the type of constituents of a gas stream. While two pieces of apparatus are classified within the same emission type, this does not automatically mean that the emission points can be controlled using the same type of control technology. For instances, storage tanks and landfills are both listed in the evaporation and breathing losses classification, but it is unlikely that a storage tank and landfill would be controlled with the same technology. In order for an emission unit to be considered similar it must fit both criteria: have a similar emission type and be controllable with the same 55 ------- Proposal June 1993 technology. Use of this classification system can be illustrated with an owner or operator of a major source within the captan production source category (a source listed on the source category list in Appendix D,) who adds additional product accumulation vessels (tanks) and additional pipes, pumps, flanges and valves to direct the product to the tanks. After reviewing a database during Tier I of the MACT analysis, the owner or operator determines that there are no regulations controlling HAP emissions from pumps within the source category; and, there is not enough emission information available on other emission units within the source category to calculate a MACT floor. During Tier II of the analysis, the owner or operator discovers that the Synthetic Organic Chemical Manufacturing Industry (SOCMI) source category has regulations for controlling equipment leaks. Because the pipes, pumps, and flanges all have equipment leak emissions, the emission units in the SOCMI source category would be considered similar emission units; and, the regulations for SOCMI equipment leaks should be considered for the control of the MACT-affected emission unit during Tier II of the analysis. Identification of a similar emission unit does not mean that the controls will automatically be applied to the MACT-affected emission unit. Costs, non-air quality health and environmental impacts, and energy requirements should be used to assess the technologies ability to meet MACT criteria. 56 ------- Proposal June 1993 3.5 Subcategorization When the source category list was developed, sources with some common features were grouped together to form a "category". During the standard-setting process, EPA may find it appropriate to combine several categories or further divide a category to distinguish among classes, types, and sizes of sources. EPA chose to establish broad source categories at the time the source category list was developed because there was too little information to anticipate specific groupings of similar sources that are appropriate for defining MACT floors for the purpose of establishing emission standards. The broad nature of some source category descriptions may pose some difficulty in establishing an appropriate MACT emission limitation for a MACT-affect emission unit on a case-by-case basis. Subcategorization within a source category for the purposes of a case-by-case MACT determination should be considered only when there is enough evidence to clearly demonstrate that there are air pollution control engineering differences. Criteria to consider include process operations (including differences between batch and continuous operations), emissions characteristics, control device applicability and costs, safety, and opportunities for pollution prevention. 57 ------- Proposal June 1993 Chapter 4.0 The MACT Floor Finding During Tier I of the MACT analysis, an owner or operator or the permitting agency is required to make a positive or negative MACT floor finding. A positive finding would be made if there is enough information to determine a emission control level that is at least equal to the MACT floor. A negative MACT floor finding would be made if: (1) the MACT floor equals "no control"; (2) a MACT floor can not be determined due to the nature of the pollutant or process; or, (3) there is not enough emissions information to compute a MACT floor. The EPA recognizes that computing the MACT floor for a MACT- affected emission unit may be time consuming and burdensome for the owner or operator or the permitting agency. To avoid calculating a specific emission control level that equals the MACT floor, while still making a positive MACT floor finding, the owner or operator can establish a MACT emission limitation based on use of the very best emission control technology. The very best emission control technology will meet or exceed the level of emission reduction required by a MACT floor finding. Owners or operators and the permitting agency should refer to existing EPA control technology guidelines (CTG), background information documents (BID,) existing New Source Performance Standards (40 CFR Part 60,) or existing National Emission Standards for Hazardous Air Pollutants (40 CFR Part 61) to determine if these 58 ------- Proposal June 1993 information sources can help to establish a particular control technology as the best for controlling HAP emissions from the MACT-affected emission unit. An owner or operator may also establish a control technology as the very best, by choosing the control technology that achieves a maximum degree of reduction in emissions of the HAPs with consideration to the costs, the non- air quality health and environmental impacts, and energy requirements. Minimal consideration should be given to cost impact in such an analysis. An owner or operator could also avoid calculating a specific MACT floor by referring to existing databases to document whether a MACT determination for another similar emission unit in the source category has recently been made. This MACT determination could be used to establish the MACT floor for the MACT-affected emission unit provided there is no reason to believe that the control technology no longer represents MACT. This was previously discussed in Section 3.1. Because the above methods will not always clearly identify a control technology or emission limitation that meets the MACT floor, an owner or operator or the permitting agency may be required to review existing emissions information to calculate a specific MACT floor. Section 4.1 of this chapter discusses the calculation procedure for determining an "average emission limitation". This procedure establishes a hierarchical system for determining the average emission limitation using the 59 ------- Proposal June 1993 arithmetic mean, median or mode. Using the calculation procedures discussed in Section 4.1, the EPA has established three acceptable methods for determining a MACT floor. If the emissions information is available, all three methods should be considered before the owner or operator concludes that a MACT floor can not be found. The three methods include using: (1) existing State and local air toxic control regulations; (2) control efficiency ratings; or (3) emission reduction ratios. Figure 3 lists these methods. Each of these methods is discussed in greater detail later in this Chapter. The first method compares air pollution regulations in different States. This method is likely to require the least amount of data search and analysis. The second and third methods base the MACT floor on a level of emission reductions, allowing the MACT-affected emission unit more flexibility in determining control technologies to meet the MACT floor. The second method is applicable only when the control technologies under consideration can be assigned an efficiency rating for HAP emission reductions. This is most-likely to occur with add-on control devises. The third method can be used for add-on control devises, work practices, recycling, reuse or pollution prevention strategies. Depending on the format of available information, a hybrid of the three approaches may be necessary. 60 ------- Figure 3 proposal June 1993 Acceptable Methods for Determining the MACT floor Emission Reduction Ratios Efficiency Ratings Existing State or Local Air Pollution Regulations Other Acceptable Methods 61 ------- Proposal June 1993 4.1 Calculation of the MACT Floor Section 112(d) of the Act instructs EPA to set emission standards for new sources based on the emissions control achieved by the best controlled similar source and to set emission standards for existing sources based on an average emission limitation achieved by the best performing 12% of existing sources or best performing five sources in the source category. For new sources the direction provided by the Act is relatively clear. For existing sources, further clarification is required by EPA to determine how an average emission limitation should be computed. The word average can have several different meanings, including arithmetic mean, median and mode. EPA has developed the following hierarchy for determining the average emission limitation that is equal to the MACT floor. First, if the emissions data that is to be used to calculate the floor is in the form of a numerical expression, (i.e. 95% reduction), the MACT floor should be determined by taking the arithmetic mean of the best performing 12% of existing sources or the best performing five sources. An arithmetic mean is calculated by summing all of the data and dividing by the number of data elements in the calculation. The following example illustrates this concept: 62 ------- Proposal June 1993 Example \ The following emission limitations are representative of the best performing 12% of existing source: % reduction 99 Average emission limitation = 99 95 656/7 = 93.7% 93 92 89 89 Total 656 # of sources = 7 Under some circumstances the arithmetic mean results in a number that may not correspond to the application of a specific control technology. For instance suppose the arithmetic mean of emission limitations of the best performing 12% of exist sources is equal to 92.3%. Application of control Technology X would provide a source 91% control, while application of Technology Z would limit the source's emissions by 96%. In most cases, when the arithmetic mean can not be specifically achieved by the application of a control technology, the MACT floor should be elevated to the level of control associated with the control technology that exceeds the MACT floor. In Example 1, the MACT emission limitation should be no less stringent than 95% control. This concept would not make sense if there is a large discrepancy between the amount of emission reductions that can be achieved by 63 ------- Proposal June 1993 available control options. This is illustrated with the following example: Example 2 An arithmetic mean is computed for the best performing 12% of storage tanks. There are 10 sources among the best performing 12% of storage tanks. Two tanks are controlled by 99%, the remaining 8 tanks are not controlled. The emissions limitations considered in the floor calculation are: % reduction 99 ... 99 average emission limitation = 0 0 19.8% reduction 0 0 0 0 0 0 Total 198 # of sources = 10 In this example, no technology corresponds to 19.8% control, and it might be inappropriate to elevate the MACT floor to 99% control. If there is a large discrepancy between the amount of emission reductions that can be achieved by available control options, the median should be used in lieu of the arithmetic mean 64 ------- Proposal June 1993 to determine the average emission limitation equal to the MACT floor. A median is the value that falls in the middle of a set of numbers when those numbers are arranged in an increasing order of magnitude; in other words, there will be an equal number of values above and below the median. If the middle falls between two values, the median is equal to the arithmetic mean of those two numbers. This situation will occur when there is an even number of values in the set of numbers. When computing the average emission limitation for the best performing 12% of existing sources, the median will always be equal to the lowest emission limitation achieved by the best 6% of sources in the source category. For example: Example 3 There are 84 sources in the source category. The number of sources in the best performing 12% of source is equal to 10. The median is to be computed for the following emissions data: % reduction 24 26 There are a total of 10 numbers 30 the median would be the arithmetic 30 mean of the 5th and 6th numbers 33 in the column. 40 56 median = (33 + 40)/2 = 36.5 88 93 99 65 ------- Proposal June 1993 Like the computation of the arithmetic mean, the value obtained for the median may not always correspond to a specific control technology. If there is a control technology that obtains slightly greater emission reduction than the median, the MACT floor should be based on that control technology. For instances, in Example 3, the MACT floor would be equal to 40% emission reductions. This value coincides with the lowest emission limitation achieved by the best performing 6% of sources. However, if there is a large discrepancy between the control technologies used to establish a median such that no technology could realistic obtain a reduction close to the median, the mode should be used to calculate the MACT floor. A mode is the most frequent occurrence among a set of data. In Example 1, the mode would be 99% emission reductions. In Example 2, the mode would be equal to 0% emission reductions; and the mode in Example 3 would be 30. The mode may also be used as a method to compute an average emission limitation if the emissions data for a source category is not based on a numerical number. This could occur if sources were regulated by several different equipment or work practice standards. Unless a specific level of emission reduction can be associated with each different standard or unless the standards can be ranked in some order of increasing level of control, an arithmetic mean and median can not be calculated. A mode could be used if one of the control options was used more frequently by 66 ------- Proposal June 1993 one of the best performing 12% of existing sources. For example: Example 4 There are 44 tanks in the source category. 5 sources would be among the best performing 12% of existing sources. These five tanks are subject to the following regulations in the source category: 3 of the 5 must be covered and vented to a carbon canister; 2 of the 5 must use a fixed roof The mode would be to cover and vent the tank to a carbon canister. The following sections of this chapter detail the three acceptable methods for computing a MACT floor. It should be noted that when the best controlled similar source is being determined for a new or reconstructed source, all references to using emissions information from within the source category should be ignored. Identifying the MACT floor for constructed and reconstructed major sources requires that the emission information used to determine the best controlled similar source not be limited to within the source category. Readers are referred to Section 3.4 of this chapter for a definition of similar emission unit. 67 ------- Proposal June 1993 4.2 Method 1 - Computing the MACT Floor Using Existing State and Local Regulations The steps for computing a MACT floor using this method are listed in Figure 4. The following describes these steps. Step (A) Conduct a geographical survey Determine the number of existing similar emission units in the source category, and conduct a survey to determine the geographical location of these similar emission units. Group the emission units according to the state or locality in which they are located. Step (B) Review State or local air pollution regulations Review the different State or local air pollution control regulations that are applicable to the emission unit in each State or locality where the emission unit is located. Step (C) Rank the State or local air pollution regulations For the State and local regulations identified in Step B, rank the regulations in order of stringency. The regulations that require the greatest level of control should be listed first. 68 ------- Figure 4 proposal June 1993 Using State or Local Air Pollution Regulations to Compute the MACT Floor Step A Conduct a Geographical Survey Step B Review State and Local Air Pollution Regulations Step C Rank the Regulations according to Stringency Step D Determine the Percentage of Emission Units Complying with each Stringency Level Step E Determine MACT Floor 69 ------- Proposal June 1993 Step (D) Determine the number of emission units regulated by each stringency level. For each level of stringency identified in Step (C), a percentage of emission units required to comply with the regulations should be computed. Step (E) Make a MACT floor finding For constructed or reconstructed major source, the MACT floor will equal the most stringent State or local regulation applying to a similar emission unit. For a modified major source, the MACT floor will either be equal to the arithmetic mean of the best 12% of existing emission units in the source category, or the best 5 existing emission units in the source category. If the arithmetic mean can not be calculated, the median or mode should be used to compute the MACT floor for existing sources. Figure 5 illustrates the following example of this concept: In Step (A), the owner or operator determines that there are 42 similar emission units in the MACT-affected emission unit's source category. Sixteen of the sources are located in State A, five in State B, three in State C, and 18 in State D. A specific numerical value can not be determined for all of these regulations, but it is possible to list the regulations in order of stringency. Upon reviewing the regulations in these four States, it is determined that States A and B have the most 70 ------- Proposal June 1993 Figure 5 Evaluation of State Regulations for Emission Unit X STATE A B C D TOTAL STRINGENCY* 1 1 2 3 # OF SOURCES 16 5 3 18 42 Total # of emission units # of emission units within the top 6% of existing emission units Stringency level top 6 emission units must comply with MACT floor = 42 =3 (42 * 0.06) = 1 regulations in State A or B * Stringency is rated from the most stringent State regulation beginning at 1 and increasing in number as the regulation is rated less stringent. 71 ------- Proposal June 1993 stringent regulations for this source; and, they are equally stringent. These State regulations are followed in stringency by State C. State D is the least stringent state; there are no regulations and the sources are uncontrolled. State A and B regulate 50% of the sources. Using the median to compute the MACT floor, the MACT floor would be equal to the least stringent regulations governing the most strictly regulated 3 sources (42 * 0.06 rounded to the next largest whole number.) In this case, the MACT floor would be equal to either State A or State B's regulations. 72 ------- Proposal June 1993 4.3 Method 2 — Computing the MACT Floor using Control Efficiency Ratings To use this method to calculated the MACT floor, the owner or operator will evaluate emission units within the source category that use add-on control devices or other methods whose HAP control efficiencies have been clearly demonstrated. See Figure 6 for a summary table of the steps for using the control efficiency rating. The MACT floor and MACT emission limitation can be computed as follows: Step (A) Determine HAP emission reduction efficiency for each control device. For each similar emission unit in the source category, the ability of each control technology to reduce HAP emissions should be determined as a percentage of reduction efficiency. Acceptable methods for determining the efficiency rating are: 1) Equipment vendor emission data and guarantees; 2) Federal and State enforceable permits limits on operation of the control technology; 3) Actual reported efficiency from the similar emission unit. 73 ------- Figure 6 proposal e June 1993 Using Control Efficiency Ratings to Compute the MACT Floor Step A Determine Efficiency of Control Technology used by other Emission Units. Step B Determine the MACT Floor. Step C Compute an Uncontrolled Emission Level(UCEL) for the MACT-Affected emission unit. Step D Compute a Controlled Emission Level (CEL) for the MACT-affected emission unit. 74 ------- Proposal June 1993 Step (B) Calculate the MACT floor For new and reconstructed emission units, the MACT floor equals the level of emission reductions that can be obtained by the control technology with the highest emission reduction efficiency. For existing emission units, the MACT floor equals the arithmetic mean of the best five or highest 12% of control efficiency ratings. Or, if the median is used the MACT floor equals the lowest control efficiency rating achieved by the best 6% of sources if there are greater than 30 sources in the source category; or, the MACT floor equals the lowest control efficiency rating among the best 3 sources if there are less than 30 sources in the source category. Under most circumstances, it should not be necessary to use the mode to compute an average emission limitation; however, if it is used, the MACT floor would be equal to the most frequent control efficiency rating among the best performing 12% of existing sources or the best performing five sources. Step (C) Determine the uncontrolled emission level for the MACT- affected emission unit Use the same procedure outline in Step D of Method 3 in Section 4.4 of this Chapter. 75 ------- Proposal June 1993 Step (D) Determine a controlled emission level for the MACT- affected emission unit Use the same procedure outlined in Step E of Method 3 in Section 4.4 of this chapter. 76 ------- Proposal June 1993 4.4 Method 3 - Computing the MACT floor Using Emissions Reduction Ratios (ERR) The emission reduction ratio is a fraction of uncontrolled emissions to controlled emissions. The MACT floor is computed using the emission reduction ratios. To compute the emission reduction ratio for each emission unit, the owner or operator must review emissions data or other information to determine uncontrolled and controlled emissions levels for these units. The step-by-step process is detailed below and summarized in Figure 7. Step (A) Compute an uncontrolled emission level (UCEL) for each similar emission unit in the source category. The uncontrolled emission level is the annual sum of all air emissions for every HAP that could be emitted from all emission points in the absence of control technologies given the maximum design capacity used by the similar emission unit within the five year period proceeding the date of application submittal. For new emission units, uncontrolled emissions should include the current design specifications for that equipment in an uncontrolled state. For example, in 1992, an owner and operator of a major source used trichloroethylene in a degreasing operation. In 77 ------- Proposal Figure? June 1993 Using the Emission Reduction Ratios to Compute the MACT Floor Step A Compute an Uncontrolled Emission Level (UCEL) for each emission unit. Step B Compute a Controlled Emission Level (CEL) for each emission unit. Step C Compute an Emission Reduction Ratio (ERR) for each emission unit. ERR = UCEL - CEL UCEL Step D Determine the MACT Floor. 78 ------- Proposal June 1993 1993, the owner or operator switched to a water-based solvent in the degreasing operation. In 1994, the owner or operator changed to using a low-VOC based solvent because the water-based solvent performed poorly. If a Section 112(j) MACT determination is conducted for the emission unit, the uncontrolled emission level would be computed using trichloroethylene in the calculation. In 1995, after already receiving the Title V permit, the owner or operator adds a degreaser (a new emission unit) that uses water- based solvents in the degreasing operation. The uncontrolled emissions for this affected emission unit would be based on the design specifications associated with the water-based solvent. The uncontrolled emission level should be based on tons/yr unless the nature of the process is more accurately reflected by computing the mass per production unit. Acceptable methods for making this calculation are: (a) Engineering calculation using material balance or emission factors; (b) Actual emission data for the similar emission unit; (c) Average annual hourly emission rate multiplied by hours of operation; (d) Emission limits and test data from EPA documents, including background information documents; (e) Equipment vendor emission data and guarantees; (f) State emission inventory questionnaires for comparable sources; 79 ------- Proposal June 1993 (g) Federal or State enforceable permit limits; or, (h) For equipment leaks use, "Protocols for Generating Unit-Specific Emission Estimates for Equipment Leaks of VOC and VHAP." Step (B) Compute a controlled emission level (CEL) for each similar emission unit or existing emission unit within the source category. The controlled emission level is the sum of all air emissions for every HAP that could be emitted from all emission points given the maximum design capacity currently in use by the similar emission unit taking into consideration the application of existing control technologies and federally enforceable limits (or for the emission unit undergoing the review, those controls that will be federally enforceable if approved as MACT) that have been placed on HAP emissions from that emission unit. This figure should be based on tons/year, unless the nature of the process is more accurately reflected on a mass per production unit basis. Acceptable methods for making this calculation are: (a) Engineering calculations using material balance or emission factors; (b) Any reported or measured emission that offers a true representation of yearly emissions; (c) Average annual hourly emission rate multiplied by hours of operation; 80 ------- Proposal June 1993 (d) Emission limits and test data from EPA documents, including background information documents; (e) Equipment vendor emission data and guarantees; (f) State emission inventory questionnaires for comparable sources; (g) Federal or State enforceable permit limits; or, (h) For equipment leaks use, "Protocols for Generating Unit-Specific Emission Estimates for Equipment Leaks of VOC and VHAP." Step (C) Compute the emission reduction ratio (ERR) for each emission unit: ERR = UCEL - CEL UCEL Step (D) Determine the MACT floor. For new or reconstructed sources the MACT floor would be equivalent to the highest ERR. For existing sources, the MACT floor equals the arithmetic mean of the best five or best 12% of ERRs. If the median is used, the MACT floor equals the lowest ERR among the best 6% of ERRs or the best three ERRs depending on the number of sources in the source category. If the mode is used, the MACT floor equals the most frequently occurring ERR among the best performing 12% of sources or best 5 sources depending on the number of sources in the source category. 81 ------- Proposal June 1993 For example, suppose a major source determined that there are four emission units in the top 12% of existing emission units for the source category. These four emission units had emission reduction ratios of 0.90, 0.92, 0.93, and 0.99. The control technologies used by these best performing 12% of similar source are a wet scrubber, a solvent change, a condenser, and an incinerator. The arithmetic mean for these values equals 0.935. If this value does not correspond to the application of a specific control technology, the MACT floor would be equal to an emission reduction ratio of 0.99. If it is determined that elevation of the MACT floor to this level is infeasible, then the median should be computed for these sources. The median would be equal to best performing 6% of sources or the lowest of the highest two emission reduction ratios. This is equal to 0.93. 82 ------- Proposal June 1993 4.5 Exceptions Emission Reduction Ratios In most circumstances the emission reduction ratio, is a reliable method for calculating the MACT floor. However, there are some circumstances when a very low emission reduction ratio could be computed for a well-controlled emission unit. This may occur if pollution prevention strategies are used for greater than five years at the major source, or a process has an inherently low potential to emit hazardous air pollutants. The owner or operator could be reducing emissions to the maximum extent possible without being able to credit the pollution prevention strategy in computing the uncontrolled emissions. The uncontrolled and controlled emission rate could be nearly the same, causing the emission reduction ratio to be a very low number. A reviewing agency should keep such situations in mind when making a MACT determination. In such instances, the pollution prevention method should not be eliminated as a candidate to meet the MACT floor. 83 ------- Proposal June 1993 4.6 Other Methods to Compute the MACT Floor As future MACT standards are proposed or promulgated for different source categories, more methods for determining the MACT floor could be developed. The reader is referred to the Federal Register to locate any other methods for calculating the MACT floor that have been approved by the EPA and used in developing a MACT standard under Section 112(d) or 112(h) of the Act. 84 ------- Proposal June 1993 Chapter 5 Costs, Non-air Health and Environmental Impacts, and Energy Requirements Section 112(d) of the Act specifies that if control technology alternatives are being considered to establish an emission standard•that would result in emission limitations more stringent than the emission "floor"; or, if insufficient data exists to specify an emission limitation based on the MACT floor, then control technology alternatives must be evaluated by considering costs, non-air quality health and environmental impacts, and energy requirements associated with the expected emission reductions. The costs, non-air quality health and environmental impacts, and energy requirements discussed below are illustrative only and are not intended as an exclusive list of considerations for MACT determinations. Some of these factors may not be appropriate in all cases, while in other instances, factors which are not included here may be relevant to the MACT determination. The discussion does not address the evaluation of each factor nor the weighing of any factor relative to another. Such determinations should be made on a case-by-case basis by the owner/operator and permitting agency. For the purpose of this discussion, terms such as "emission control system" or "MACT system" refer to design, equipment, or operating standards and inherently less 85 ------- Proposal June 1993 polluting processes, as well as add-on control equipment. In general, the impact analyses for MACT determinations should address the direct impacts of alternative control systems. Indirect energy or environmental impacts are usually difficult to assess, but may be considered when such impacts are found to be significant and quantifiable. Indirect energy impacts include such impacts as energy to produce raw materials for construction of control equipment, increased use of imported oil, or increased fuel use in the utility grid. Indirect environmental impacts include such considerations as pollution at an off-site manufacturing facility which produces materials needed to construct or operate a proposed control system. Indirect impacts generally will not be considered in the MACT analysis since the complexity of consumption and production patterns in the economy makes those impacts difficult to quantify. For example, since manufacturers purchase capital equipment and supplies from many suppliers, who in turn purchase goods from other suppliers, accurate assessment of indirect impacts may not be possible. Raw materials may be needed to operate control equipment, and suppliers of these resources may change over time. Similarly, it is usually not possible to determine specific power stations and fuel sources which would be used to satisfy demand over the lifetime of a control device. In most cases, duplicative analyses are not required in preparing the MACT impact analyses. Any studies previously 86 ------- Proposal June 1993 performed for Environmental Impact Statements, water pollution permits, or other programs may be used when appropriate; however, the permitting agency may consider any special economic or physical constraints which might limit the application of certain control techniques to an existing emission unit, such as retro-fitting costs that would not be borne by a new unit, or the remaining useful life of the emission unit. The result may be that the level of control required for an existing emissions unit may not be as stringent as that which would be required if the same unit were being newly constructed at an existing plant or at a "greenfield" facility. However, in no event shall the level of control yield an emission limit less stringent than the MACT floor when information is available to compute the MACT floor. 5.1 Cost Impacts Cost impacts are the costs associated with installing operating, and maintaining alternative emission control systems (add-on emission control devices or process changes.) Normally, the submittal of very detailed and comprehensive cost data is not necessary. Presentation of the quantified costs of various emission control systems (referred to as control costs,) coupled with quantities of HAP emission reductions associated with each of the emissions control systems, is usually sufficient. Once the control technology alternatives and emission 87 ------- Proposal June 1993 performance levels have been identified, total capital investment and total annual cost should be developed. Total capital investment (purchased equipment plus installation) and total annual costs of each emission control system should be presented separately. Total annual coasts are comprised of operation and maintenance costs ("direct annual costs",) administrative changes ("indirect annual costs"), plus overhead, taxes, insurance, and capital recovery costs minus recovery credits (credit for product recovery and by-product sales generated from the use of control systems and other emission reduction credits.) These costs should be reported in equal end-of-year payments over the time of the equipment. Total annual costs should be reported on an overall basis, as well as an incremental basis. The various emission control systems should be presented or arrayed in terms of increasing total annual cost. The incremental annual cost of a particular emission control system is the difference in its cost and the cost of the next less stringent control. A method for determining the excessiveness or acceptability of control costs is the comparison of the cost-effectiveness of alternative control systems. Cost-effectiveness is the ratio of total annual costs (calculated using the above guidelines) to the total amount (tons or Mg) of HAP removed. Incremental cost effectiveness is calculated using the same procedure as outlined for calculating incremental annual cost. Generally, cost- effectiveness falling within the range of previously acceptable 88 ------- Proposal June 1993 MACT decisions are not considered excessive. Therefore, consistency with the relative cost, or cost effectiveness, of a past MACT determination for a similar source is an indication that such a cost is reasonable for the MACT determination in question. For most MACT determinations, a cost analysis focusing on incremental cost-effectiveness of various MACT alternatives is sufficient. The analysis should include and distinguish the various components used to calculate the incremental cost- effectiveness of the control alternatives (i.e., lifetime of the equipment, total annual costs, tons of total HAP removed, etc.). If there is reason to believe that the control costs place a significant burden on the entity being controlled, then the cost analysis should include financial or economic data that provide an indication of the affordability of a control relative to the source. For example, if the per unit cost is a significant portion of the unit price of a product or if the economic status of the industry is declining, then the cost analysis should present the relevant economic or financial data. Financial or economic data should include parameters such as after-tax income or total liabilities. An example of a financial criterion used to determine affordability would be the ratio of a facility's capital costs to the facility's parent company's total liabilities. This ratio would provide an assessment of the company's capital structure. 89 ------- Proposal June 1993 5.2 Environmental impacts The environmental impacts concentrate on collateral environmental impacts due to control of emissions of the pollutant in question, such as solid or hazardous waste generation, discharges of polluted water from a control device, visibility impacts (e.g. visible steam plume), or emissions of other air pollutants. The applicant should identify any environmental impacts associated with a control alternative that has the potential to affect the selection or rejection of that control alternative. Some control technologies may have potentially significant secondary environmental impacts. Scrubber effluent, for example, may affect water quality and land use, and, similarly, technologies using cooling towers may affect visibility. Other examples of secondary environmental impacts could include hazardous waste discharges, such as spent catalysts or contaminated carbon. Generally, these types of environmental concerns become important when sensitive site-specific receptors exist or when the incremental emissions reduction potential of one control option is only marginally greater than the next most effective option. The procedure for conducting an analysis of environmental impacts should be made based on a consideration of site-specific circumstances. In general, the analysis of environmental impacts starts with the identification and quantification of the solid, liquid, and gaseous discharges from the control device or devices 90 ------- Proposal June 1993 under review. Initially, a qualitative or semi-quantitative screening can be performed to narrow the analysis to discharges with potential for causing adverse environmental effects. Next, the mass and composition of any such discharges should be assessed and quantified to the extent possible, based on readily available information. As previously mentioned, the analysis need only address those control alternatives with any environmental impacts that have the potential to affect the selection or rejection of a control alternative. Pertinent information about the public or environmental consequences of releasing these materials should also be assembled. Thus, the relative environmental impacts (both positive and negative) of the various alternatives can be compared with each other. Also the generation or reduction of toxic and hazardous emissions other than those for which the MACT determination is being made and compounds not regulated under the Clean Air Act are considered part of the environmental impacts analysis. A permitting authority should take into account the ability of a given control alternative for regulated pollutants to affect emissions of pollutants not subject to regulation under the Clean Air Act in making MACT decisions. Consequently, the ability of a given control alternative to control toxic or hazardous air contaminants other than those for which the MACT determination is being made, should be considered in the MACT analysis. 91 ------- Proposal June 1993 4.3 Energy Impacts Energy impacts should address energy use in terms of penalties or benefits associated with a control system and the direct effects of such energy use on the facility. A source may, for example, benefit from the combustion of a concentrated gas stream rich in volatile organic compounds; on the other hand, extra fuel or electricity is frequently required to power a control device or incinerate a dilute gas stream. If such benefits or penalties exist, they should be quantified to the extent possible. In quantifying energy impacts, the application could estimate the direct energy impacts of the control alternative in units of energy consumption at the source (e.g., Btu, Kwh, barrels of oil, tons of coal). The energy requirements of the control options could be shown in terms of total and/or incremental energy costs per ton of pollutant removed. In many cases, because energy penalties or benefits can usually be quantified in terms of additional cost or income to the source, the energy impacts analysis can be converted into dollar costs and, where appropriate, be factored into the cost analysis. Indirect energy impacts (such as energy to produce raw materials for construction of control equipment) are usually not considered. However, if the reviewing agency determines, either independently or based on a showing by the applicant, that an indirect energy impact is unusual or significant, the indirect 92 ------- Proposal June 1993 impact may be considered. The energy impact should still, however, relate to the application of the control alternative and not to a concern over energy impacts associated with the project in general. The energy impact analysis may also address the concern over the use of locally scarce fuels. The designation of a scarce fuel may vary from region to region, but in general a scarce fuel is one which is in short supply locally and can be better used for alternative purposes, or one which may not be reasonably available to the source either at the present time or in the near future. 93 ------- Proposal June 1993 Chapter 6.0 Sources of Information There are currently several programs under development to house and disseminate toxics information. Some of these programs are designed for specific, narrow purposes, while others are employed in a broader range of uses. Many data collection programs are designed for immediate interface with the AIRS toxics program, which is currently under development. The purpose of this chapter is to present various sources of toxics information available in a database format. EPA believes the requirements of 112(g) can be less burdensome to both industry and States by employing a database system to calculate the 12% floor which may involve using complex mathematical algorithms and procedures. BACT/LAER CLEARINGHOUSE INFORMATION SYSTEM (BLIS) The BACT/LAER Clearinghouse, or the BACT/LAER Information System (BLIS) is a database consisting of best achievable control technology (BACT) determination information on specific sources, to a process level. Database parameters include facility information; process description; pollutant information; control device type, installation date, efficiency; and calculation method; and stack test information if it exists. 94 ------- Proposal June 1993 Participation in BLIS is on a voluntary basis. If participation in BLIS increases, it may be able to provide sufficient information to determine the 12% floor with increasing accuracy. BLIS has undergone substantial revision. Additional fields for use with toxics work have been added, changes to improve "user-friendliness" of the system, such as menus and help screens have been added, and BLIS is now available on the TTN Bulletin Board. JEI06 PROGRAMS The Joint Emissions Inventory Oversight Group (JEIOG), support for a data system for air toxics emissions inventories focuses on the expressed reguirements of the urban area source program (UASP, Section 112(k), of the CAAA) and the Great Waters Program (GWP, Section 112(m)). Under the JEIOG programs, there are both short term, immediate needs and long-term needs. Since the UASP data collection effort is scheduled to be completed by mid-1994, JEIOG may need to select a system for immediately use by the Urban Area Source Program. Urban Area Source Program The Urban Area Source Program (UASP) is collecting emission 95 ------- Proposal June 1993 inventory data for use by mid -1994 to meet the CAA November 1995 date for development of a national strategy for control of HAP emissions in urban areas. The inventory focuses on an adequate number of urban areas to "understand the urban area source problem." Baltimore, Chicago and Houston are the leading candidate cities. Other cities could be added (such as Milwaukee, Detroit or Seattle) as the resources become available. The primary data need is for a single year "snapshot" of emissions data for use in developing the national control strategy plan. As of the date of this writing, JEIOG has not committed to any single system for storing the UASP data. AIRS is under consideration with other database systems. Great Waters Program The Great Waters program requires HAP emissions data for most of the U.S. and portions of Canada. The Great Lakes region probably requires the most attention. Biennial assessments as reports to Congress are required under the Great Waters program. The first report is expected in November 1993. Emissions inventory data are used primarily for input to models for the assessment of the relative atmospheric loading of toxic pollutants into the Great Lakes and other waterways. Updates of the emission inventory are anticipated to support the periodic assessments and for input to refined models as they become available. 96 ------- Proposal June 1993 GENERIC ICR DATA (SECTION 114) Under the Authority of Section 114, EPA developed a survey to obtain the information needed to calculate regulatory floors for both new and existing stationary sources (See Appendix ). This survey is commonly referred to as a "generic ICR", or information collection request. It is customized within narrow parameters for each source category, and comes in both a "long form" and a "short form". EPA sends the survey to facilities at the time it initiates regulatory development for the affected source category. In other words, the survey is not sent to facilities in all source categories at the same time. In the generic ICR, EPA requests information regarding each compound identified as a HAP that is used in or emitted by any operations, including fugitive emissions sources, occurring from the source category at the facility. Recipients of the form are required to fill out the information request as completely as possible from existing information. At a minimum, the facility must provide (1) information of the presence of HAP emissions and (2) HAP emission estimates based on previously obtained test data or on engineering calculations provided there is a basis for such calculations. Since the Generic ICR data is collected by EPA from industries, it is called "Agency data". As such, it can not be used to update (or replace) existing data which was obtained from 97 ------- Proposal June 1993 States, or "State data". The ICR data is currently stored and analyzed on a commercial database software files. The Agency is evaluating options to make the ICR data "safe" (without confidential information) and accessible to States on a workfile within AIRS/AFS. XATEF: TOXIC EMISSION FACTORS The requirements of the CAAA dictate immediate sampling and analysis to obtain data for determination of emission factors. These emission factors will be used to determine control measures. EPA developed screening methods for the development of air toxics emission factors, and applies the screening to test results as they become available for use. The EPA is enhancing the XATEF system for housing and manipulating the data. The XATEF system is being redesigned to export toxic emission factors, in a form similar to the AFSEF package for criteria pollutants. The new system should be available by the fall of 1992. The toxic emission factors available through the XATEF system will be rated A (most reliable, based on several tests meeting high confidence criteria) through E (least reliable, having limited available information), similar to the way criteria emission factors are presented in the AP-42. Toxic emission factors are being developed for 400 toxic 98 ------- Proposal June 1993 compounds, of which about 170 are on the list of 189 HAPs in Section 112(b). About 40 of these have been targeted as "critical" pollutants because they are found in a wide variety of industries, and/or are especially toxic. This group of about 40 toxic compounds have a rating of A or B, enabling users to arrive at the most accurate emissions estimates presently possible. 99 ------- Proposal June 1993 AIRS/APS NATIONAL OPERATING PERMIT SYSTEM The EPA promulgated a new part 70 of Chapter I of title 40 of the Code of Federal Regulations (CFR) on July 21, 1992, establishing provisions for the Operating Permit Program, and the minimum data elements of State operating permit programs. States must develop and submit programs for issuing operating permits to major stationary sources of HAPs. The requirements of Section 112(g)(2) (A&B) are triggered by the effective date of a permit program under Title V in any State. Section 112(g)(3) states that "the Administrator (or the State) shall establish reasonable procedures for assuring that the requirements applying to modifications under this section are reflected in the permit". The most far-reaching program established under the CAAA is that of a national operating permit program under Title V. The National Air Data Branch (NADB) is developing a database as a subsystem under AIRS/AFS to handle the new data coining in from States Title V permit programs. This database is generally referred to as the permit system. The permit system is under design to provide much of the information needed for determining the MACT floor both for case-by-case MACT determinations and for MACT standards. It is expected that this system will become available for use by the fall of 1993. 100 ------- Proposal June 1993 AEROMETRIC INFORMATION RETRIEVAL SYSTEM (AIRS) TOXICS PROGRAM The Aerometric Information Retrieval System (AIRS) was designed and executed to accommodate the expansion of emissions data. AIRS Facility Subsystem (AFS) is the stationary source component of this system and replaced the old NEDS as the data repository for point source data (e.g., electric utilities, industrial plants and commercial enterprises). Enhancement of AIRS continues to support the new programs designated by the CAAA. The National Air Data Branch (NADB) is currently considering data support of the requirements under Section 112 for HAP. NATICH The National Air Toxics Information Clearinghouse (NATICH) has been established by EPA to support State and local agencies in the control of non-criteria air pollutants. The NATICH program has both a database and a reporting capability. The database component of the clearinghouse contains information on various air toxics regulatory programs administered through State and local agencies. Elements such as permitting, source testing, ambient monitoring, agency contacts, acceptable ambient limits and guidelines, and program overviews are all contained within the database. Information is collected 101 ------- Proposal June 1993 on an annual basis by voluntary submittal from participating agencies. Since its introduction in 1984, NATICH has undergone periodic modifications in an attempt to expand and meet the needs of the user community. In the fall of 1989, a link was established between NATICH and the Toxic Release Inventory System (TRIS). A modification is in the planning stages to move the database from the NCC's IBM mainframe onto the OAQPS TTN Bulletin Board System for easier and wider accessibility. STATE AIR OFFICE DATABASES Emissions Standards Division (ESD) staff have been working with STAPPA/ALAPCO to better characterize the toxics information available in database form and hard copy within the State air offices. Most States have compiled pollutant information in some form in response to State Implementation Plan (SIP) requirements. Many States also have toxics information collection systems, as well as State requirements for toxics programs in the air offices. Most States find that although internally their system is widely used (intra-State system), to down load or upload data on an inter-State basis is nearly impossible (with the primary exception to this being States within a transport region, and 102 ------- Proposal June 1993 then usually under limited circumstances). Many States have expressed a keen interest in a National database that each State could down load State-specific data into, and upload multi-State retrievals from. This capability is met by three main systems in EPA: BLIS, AIRS, and NATICH. Many States use the Aerometric Information Retrieval System (AIRS) to input their information and perform calculations and retrievals. When a converter (an interface between AIRS and the State system) is used, the data can be input directly into the State system and the converter then enters it into the appropriate fields in AIRS. Data can also be retrieved from AIRS into the State format with a converter. Since many data sources are fed into AIRS/AFS, the system becomes a repository of a vast amount of data. A great deal of this will be useful for case-by-case MACT determinations and MACT standards. This advantage is expected to become more visible as the search for the 12% floor for a source category becomes a common occurrence. Some State data is not generally found in the State systems because it is not needed for their current reporting requirements. However, much of the information missing from the database system can be found in the files documenting source categories and processes of industry reports. States may wish to enhance their current systems to hold such additional data fields 103 ------- Proposal June 1993 and data elements from their participating industries. OTHER SOURCES OF INFORMATION TRADE JOURNALS Caution should be taken when employing these sources, especially in noting the method of emissions estimation, number of tests which were used in developing estimates, and the conditions under which tests were conducted. Other factors which may affect the emissions estimates should also be identified, and the effects of their differences quantified as accurately as possible. Because results applicable to only one facility can not be completely accurate for other facilities, this source of information is not regarded as highly accurate. This source of information may be somewhat biased as trade journals are commonly published and funded by the industry members of a trade association. However, these journals are completely acceptable as long as the results used can be substantiated. TOXIC RELEASE INVENTORY SYSTEM (TRIS) This is a source of data that was used to identify HAP emitters. The TRIS database contains emissions data reported by individual industrial facilities as required under Section 313 of the Emergency Planning and Community Right-to-Know Act of 1988. 104 ------- Proposal June 1993 Emissions data in TRIS are reported on a plant wide basis. Standard Industrial Classification (SIC) Codes are reported in TRIS but the entries are usually not specific enough to identify categories of sources. The TRIS database is reportedly capable of identifying plants emitting pollutants listed in Section 112(b). 105 ------- Proposal June 1993 List of References Air Pollution Training Institute (APTI). December 1983. Overview of PSD Regulations. EPA 450/2-82-008. Air Pollution Treaining Institute (APTI). June 1983. Air Pollution Control Systems for Selected Industries. EPA 450/2-82-006. Environmental Protection Agency (EPA). May 1992. Facility Pollution Prevention Guide. EPA, 600/R-92/088. Environmental Protection Agency (EPA). February 1992. Documentation for Developing the Initial Source Category List. EPA, 450/3-91-030 Environmental Protection Agency (EPA). June 1991. Hazardous Waste TSDF - Background Information for Proposed RCRA Air Emission Standards. EPA, 450/3-89-023 (a) and (c). Environmental Protection Agency (EPA). October, 1990. New Source Review Workshop Manual. EPA, Research Triangle Park, NC (Draft Document). 106 ------- Proposal June 1993 Environmental Protection Agency (EPA), January 1990. OAOPS Control Cost Manual. EPA, 450/3-90-006. Environmental Protection Agency (EPA). September 1986. Control Technologies for Hazardous Air Pollutants. EPA, 625/6-86-014. 107 ------- Proposal June 1993 Appendix A The following detailed examples presented in this manual are for illustrative purposes only. Numbers and values presented in this Appendix do not necessarily reflect any known cases and are not meant to establish any US EPA position regarding MACT determinations for a particular MACT-affected source. These examples are fictitious and are designed to highlight many of the subtle aspects of the MACT determination process. In many cases, the scenarios and available control technologies have been grossly oversimplified to streamline the presentation of the examples. The proceeding examples assume that an owner or operator has already determined that the major source will be constructed, reconstructed or modified. ------- Proposal June 1993 Example l Determining the MACT-Affected Emission Unit The owner or operator of a major source in the miscellaneous metal parts source category is subject to a MACT determination under Section 112(j). The following is a description of the source and the operations at the facility: A metal furniture manufacture produces military- specification office furniture for use in military barracks. The plant currently operates 2080 hr/yr and produces 12,000 units of furniture annually. Estimated emissions from the major source are 100 tpy of HAPs. Existing unit operations include: 1) wood processing Raw wood and formica are glued together to form a laminate. The glue is applied using an automatic application system. Several laminates are then positioned in a press for glue curing. Next, the boards undergo various woodworking operations including, cutting, drilling, and routing. Boards are either transferred to assembly or directly packaged and shipped. Tetrachloroethylene is a component of the glue. Glue stations are vented to emission stacks on A - 2 ------- Proposal June 1993 the ceiling. The stacks are currently uncontrolled. The glue is stored in 50 gallon drums. Glue is transferred to the application equipment through a pumping mechanism. Estimated yearly emissions of HAP from this operation is 0.50 tpy. 2) Metal Processing Metal stock is cleaned by immersion in a toluene dip tank. A toluene, grease, and dirt sludge is produced which is pumped from the bottom of the tank for disposal. After cleaning the metal undergoes various metalworking operations including cutting, punching, folding and welding. Pieces are partially assembled, then transferred to one of two paint coating operations. The dip tank is currently controlled with a condensing unit and a freeboard ratio of 0.75. Yearly controlled emissions are estimated at 19 tons/yr. Uncontrolled emissions are estimated at 55 tpy. 3) Cleaning operations: The spray coating operations begins with a five-stage cleaning. The first stage is an alkaline-wash tank. Next, parts are sprayed with an iron phosphate solution. The fourth stage is a rinse tank. Finally, parts are sprayed with a rust preventive. A - 3 ------- Proposal June 1993 After cleaning, the parts are conveyed to a dry-off oven and then the paint coating line. No HAP emissions occur during this part of the operation. 4) Painting operations: There are currently four spray booths in the paint coating operation, and one dip-spray tank. Large metal parts are coated using the spray booths. A one color coating is applied at a coating depth of 1 ml. Two of the booths are equipped with continuously recirculating water curtains to entrap paint overspray. Entrapped paint solids and wastewater are dumped to a holding tank periodically. Air filters are used in the two remaining spray booths. The Air filters are periodically replaced. The used filters are placed in storage drums for later disposal. All spray booths are equipped with hand-held spray guns. Transfer efficiency is estimated at 45% for both types of booths. The paint is a high solvent paint containing xylene and toluene with an estimated 35% solids content and 65% solvent content. The spray guns are periodically sparged and rinsed with acetone to prevent clogging. The acetone paint mixture is sent to storage tanks for later disposal. Emissions from the booths are currently vented to the roof with no control devise. After painting parts are conveyed through a flash-off A - 4 ------- Proposal June 1993 area to one of two dry-off ovens and then to assembly. Small metal parts are dip-painted, allowed to air dry, and then transferred to the assembly area. Total annual HAP emissions from this area are estimated at 55 tpy. Each spray booth contributes 8 tpy and each drying oven 4 tpy. Estimated emissions from the dip-spray tank are 15 tpy. No emission estimates are available for the flash-off area. From this description the following emission points are indentified as potentially "affected emission points" by the Section 112(j) MACT determination process: glue storage drums glue stations (stack emissions) —application equipment —curing presses dip tank* toluene storage tanks* toluene/sludge waste storage tanks* spray booths (stack emissions) — feed and waste lines — application equipment spray dip-tank flash-off area (large parts) drying area (small parts) paint storage tanks solvent storage vessels paint sludge storage tanks drying ovens (stack emissions) Air filter storage drums * These unit would be eliminated from any MACT-affected emission unit because the emission points would be part of the degreasing source category, not the miscellaneous metal A - 5 ------- Proposal June 1993 parts surface coating source category. Possible MACT-affected emission unit scenarios: Scenario #1 There would be five MACT-affected emission units: Wood processing Spray coating operations Storage tanks Equipment leaks storage drums The above scenario could make sense if a MACT floor could be identified or control technologies could be applied to the emission units. In wood processing the emissions are vented to a stack on the roof. These emissions could be controlled with a variety of add-on control devices. The source could also consider switching to a glue that has a lower concentration of a HAP or does not contain any HAPs. In the spray operations, the source could switch to a low solvent paint or water-based paint. This control option would need to be weighed against controlling the individual emission points. Other control options to consider would be an add-on control devise to control the stack emissions from the spray booth and oven, increasing the transfer efficiency of the spray application equipment, and controlling the drying, flash-off areas, and the dip-spray tank with separate control technologies. Controlling the storage tanks as one emission unit may allow flexibility in meeting MACT. Some tanks could remain under A - 6 ------- Proposal June 1993 controlled while others could be over-controlled. This option would need to be weighed against the cost effectiveness and emission reductions of applying controls to all of the storage tanks. The storage drums could be placed in a contained area and the emissions vented to one control devise. Scenario #2 Stack emissions (spray booths, glue stations, drying ovens) storage tanks and drums equipment leaks dip-spray tank In this scenario, the stack emissions from the spray booths, glue stations and drying oven could all be vented to a single control devise. This option would need to be weighed against the emission reductions that could be obtained by applying pollution prevention strategies to the individual operations. If the storage tanks and drums are stored in a common location, such that the emissions from the area could be vented to a control devise, this emission point aggregation could make sense. The emission reduction would need to be weighed against controlling the emission points separately. If greater emission reductions could be obtained by controlling these points separately, this aggregation of points may not be acceptable. A - ------- Proposal June 1993 Scenario #3 each storage tank each spray booth stack emissions from glue stations and drying oven equipment leaks each storage tank each storage drum dip-spray tank This scenario would generally be acceptable unless a pollution prevention method could be applied to one of the processes that could obtain a greater degree of emission reductions then point-by-point compliance. Scenario #4 All emission points This scenario would generally be unacceptable because equipment leak emissions should not be included in a source category wide emission unit. A - 8 ------- Proposal June 1993 Scenario #5 equipment leaks remaining emission points This aggregation of emission units could be acceptable if emissions information were available on HAP emissions or control technologies from the source category as a whole, or if the nature of the industry demanded a large degree of flexibility in the application of MACT. A justification for this conglomeration would be necessary. A - ------- Proposal June 1993 Example 2 Using control Efficiency Ratings to Determine the MACT Floor A MACT determination is to be conducted on a quenching process at a coke-by product plant. Hazardous emissions can be released when the hot coke in the quench car is sprayed with water to decrease the coke's temperature. Phenol and naphthalene emissions can occur in the gaseous state. Other pollutants can sorb to particulate matter and be collectively released. The owner or operator will need to conduct a MACT analysis to recommend a MACT emission limitation and specify a control technology to comply with the MACT floor for existing major sources. The owner or operator will begin with the Tier I analysis. Steps 1) Identify the MACT-affected emission unit(s) MACT-affected source: quenching tower and coke car # of existing sources: 36 The equipment used in this production process include the quenching tower, the coke car, water delivery system, and water storage system. After consulting with the permitting agency, it is decided that emission points from the quenching tower and coke car should be considered one MACT-affected emission unit, and the water delivery system and water storage system as another affected emission unit. The example will be continued for only the quench tower/coke car emission unit. A - 10 ------- Proposal June 1993 Step 2) Make a MACT floor Finding Technology 1) Use clean water to quench coke with baffles at the top of the quench tower of plants using 10 %efficiencv not quantifiable 2) Use covered quenched car. Cool outside of car. Water does not impact coke. Place car on cooling rack after quenching for additional heat dissipation. almost 100% 3) Wet scrubber, connected to fixed duct system 4) Wet scrubber, mobile unit attached to coke quench car 5) Dry quenching with inert gases. Heat transported to waste-heat boiler 10 14 80-90% 80-90% 99-100% A - 11 ------- Proposal June 1993 The owner or operator has decided to use the control efficiency ratings to determine the MACT floor. There are a total of 36 existing sources. The MACT floor would be equivalent to the arithmetic mean of the control efficiency ratings for the best five sources. If a specific control efficiency rating is not available for the best performing five sources, a median or mode could be used to calculate the MACT floor. Using the information provided, the median of the best performing 12% of sources would be equal to 80-90% or control technology 3 or 4. The mode would be technology number 4. Step 4 Select a control technology as the MACT Technologies 2, 3, 4, or 5 could be chosen as MACT. Number 1 could also be consider because its control efficiency is not quantifiable. If the owner wished to consider technology 1, a more detailed analysis would be required to prove that the technology could obtain an equal or greater amount of emission reductions. In this case, the efficiency of technology 1 will vary by the concentration of hazardous constituents. Using clean water could result in a less toxic release when the concentration of toxins in the hot coke are less, but increased emissions could result with increased concentrations. The other proposed technologies would operate at a relatively constant efficiency rate, regardless of the pollutant concentration. Therefore, A - 12 ------- Proposal June 1993 technology number 1 would be considered inferior and should be eliminated as a potential candidate. The owner or operator should consult with the reviewing agency to determine whether a costs, non air quality health and environmental impacts and energy requirements analysis is required for the available control technologies. If not, the owner or operator could select any of these control technologies. If an analysis is required, the control technology achieving a maximum degree of reduction in emissions of the HAPs should be selected based on the costs, non-air quality environmental and health impacts and energy requirements analysis. After selecting the technology the owner or operator would proceed to Tier III of the analysis. In Tier III, the appropriate operation conditions and design specification would be prescribed in lieu of a specific MACT emission limitation. A - 13 ------- Proposal June 1993 Example 2 When the MACT floor is Determined using Emission Reduction Ratios Description of Source A surface coating operation treats a product with its existing equipment consisting of a dip-tank priming stage followed by a two-step spray application and bake-on enamel finish coat. The product is a specialized electronics component (resistor) with strict resistance property specifications that restrict the types of coatings that may be employed. Step 1) Identify the MACT-affected emission unit(s) MACT-affected emission units - 1. dip-tank 2. feed and waste lines in prime coating operation 3. spray coat booth, spray coat application equipment 4. drying oven 5. storage tank in prime coating operation 6. storage tank in finish coating line There are two process units within this source category: the prime coating line and the finish coating line. Equipment within the prime coating line that have affected emission points are a dip-tank, storage containers, feed line to supply new coating into the dip-tank, a waste line to drain the dip-tank. Because A - 14 ------- Proposal June 1993 the feed line and waste lines have equipment leak emissions, these emission points should be combined to form a MACT-affected emission unit. The owner or operator will consider the dip-tank and each storage container a separate affected emission unit. The three MACT-affected emission units in this process unit are the dip-tank, the storage container, and the feed and waste lines. The finish coating line consists of two spray booths, spray application equipment, paint supply system, a storage container, and a drying oven. After consulting with the permitting agency, the owner or operator combines affected emission points to form the following MACT-affected emission units: the spray application equipment and spray booths; the paint supply system, the storage container, and the drying oven. For simplicity of this example, the MACT analysis will be continued for only the spray application equipment and spray booths. A - 15 ------- Proposal June 1993 Step 2) Make a MACT floor finding Steps A and B: Computing the Uncontrolled Emissions and Controlled Emissions Overview Analysis of emissions information for similar emission units within the source category: Technology * of sources using 1) water-based coat 2 2) low-VOC solvent/high 4 solids coat 3) electrostatic spray 7 application to enhance transfer efficiency 4) low voc solvent/high solids 8 coating with electrostatic spray application 5) powder coat paint with 1 electrostatic spray application 6) high-voc solvent coating 8 A - 16 ------- Proposal June 1993 Detailed analysis Source 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Technology # 6 3 2 3 3 6 6 3 2 2 6 6 6 3 2 3 4 5 4 3 4 4 Uncontrolled emissions (tons/yr) 10 26 48 86 98 26 35 78 69 15 11 12 23 85 141 25 159 126 35 25 68 46 Controlled emissions (tons/yr) 10 14 22 56 55 22 34 55 25 11 11 12 22 52 89 20 100 11 14 16 22 10 Emission reduction ratio 0 .46 .54 .35 .44 .15 .03 .29 .64 .27 0 0 .04 .39 .39 .20 .37 .91 .6 .36 .70 .78 A - 17 ------- Proposal June 1993 Source 23 24 26 27 28 29 30 Technology # 1 L_6 4 4 4 4 6 1 Uncontrolled emissions (tons/yr) 95 96 64 98 168 196 186 255 ' > != Controlled emissions (tons/yr) 10 16 25 31 45 63 186 26 Emission Reduction Ratio .89 .83 .61 .68 .73 .68 0 .90 A - 18 ------- Proposal June 1993 Step C Computing the Emission Reduction Ratio for the MACT- Affected Emission Unit Because there are 30 sources, the MACT floor should be based on the arithmetic mean of the emission reduction ratios achieved by the best 12% of existing emission units. Twelve percent of 30 emission units is equal to 3.5 sources. The owner or operator should round up all fractions to the next largest number. The MACT floor would be equal to the arithmetic mean of the emission reductions obtained by the best 4 sources in the source category. Reviewing the data above the MACT floor would be equal to an emission reduction ratio of 0.88 ([0.91 + 0.90 + 0.89 + 0.83]/4) or the emission reductions that can be achieved when control technologies 1 or 5 are used. In this example, the nature of the product requires a specific type of coating. Technology 1 and 5 are inappropriate for application to this MACT-affected emission unit. The owner or operator would continue with the analysis to identify other technologies that can meet a 0.88 emission reduction ratio. Step D Determine a MACT emission limitation (MEL) The owner or operator of the MACT-affected emission unit needs to calculate an uncontrolled emission rate for the MACT- af fected emission unit. Because current design specifications for existing emission unit cause a larger uncontrolled emission rate than any other designs used in the past 5 years, the current A - 19 ------- Proposal June 1993 operational designs will be used to determine the uncontrolled emissions. With the existing coating material, the MACT-affected emission unit has an uncontrolled emission level of 125 tons/yr total HAPs. The MEL for this emission unit would be MEL = 125 tons/yr * (1 - 0.88) = 15 tons/yr Step 4 Select a control technology to meet the MACT Emission Limitation. In this case, the owner or operator must select a control technology that allows the source to meet the MACT emission limitation. Because the owner and operator can not use any of the identified control technologies to meet the MACT floor, control technologies to control similar emission points will be considered. In this example, the similar emission points have operational losses. Review of control technologies to control operational losses identifies add-on control devises such as a carbon absorber, a thermal or catalytic incinerator, or a condenser. The owner or operator should conduct a costs, non-air quality health and environmental impacts and energy requirements analysis on the available control technologies. The major source already has a catalytic incinerator on site. The emissions from the spray application equipment and spray booth could be channeled to the incinerator. This would A - 20 ------- Proposal June 1993 require the installation of a venting system including a pump mechanism. It would also require an increased volumetric flow rate to the incinerator and increase auxiliary fuel requirements. The incinerator had been operating at a 90% efficiency. With an increased volumetric flow rate, the efficiency is projected to drop to 87% efficiency. The owner and operator must obtain an additional 1% emission reductions. Possible control technologies include increasing the operating temperature of the incinerator, or adding electrostatic application to the spray process to enhance transfer efficiency. Limiting the hours of operation at the MACT-affected emission unit could be considered if the reduced production were part of an overall source reduction program. Use of the specialized coating in this operation will increase the concentration of hazardous pollutants in the water used for the water curtain. The proposed control technology does not affect the concentration of pollutants in the wastewater. This could be considered a negative environmental impact and may be reason to consider another control technology to meet the MACT emission limitation. In this instance, the owner or operator will not violate the NPDES permit, so the MACT candidate will not be eliminated from consideration. The owner or operator uses this step to demonstrate that despite the increase in volumetric flow rate and the auxiliary A - 21 ------- Proposal June 1993 fuel requirement, a significant increase in CO2 emissions does not occur. The owner or operator concludes that the impacts associated with use of this technology are reasonable. After reviewing the technologies the owner or operator selects the incinerator with a limit on the hours of operation. The owner or operator proposes to start a training program for spray booth operators to decrease the error and product rejection rate. By doing this, the owner or operator can reduce the hours of operation and still meet customer demands for the product. This option was chosen over the other two because increasing the incinerator's operating temperature would require additional auxiliary fuel input, and enhancing the transfer efficiency with electrostatic application would be cost prohibitive. The owner or operator would document that use of the selected control technologies can reduce emissions to the required level. The owner or operator would move to Tier III of the analysis and document the MACT emission limitation, and suggest appropriate conditions to assure that this MACT emission limitation is federally enforceable. A - 22 ------- Proposal June 1993 Example 3 When the MACT floor is Equal to "No Control" A commercial treatment storage and disposal facility receives off-site wastes from various pesticide manufacturers. A solvent/aqueous/pesticide mixed waste is passed through a distillation column where the organic solvents are vaporized and then condensed into a distillate receiver. The solvent is transferred using tank cars to a tank farm that is located at another portion of the plant. The low-grade solvent is then sold to industrial users. The pesticide-laden wastewater is then passed through a series of carbon adsorbed where the majority of pesticide is removed from the water. The water is then discharged to a Publically Owned Treatment Works (POTW). The carbon adsorbers are periodically steam stripped to regenerate the carbon. Step 1) Identify the MACT-affected emission unit(s) MACT-affected emission units: 1) each storage tank 2) the distillation column, condenser, and distillate receiver 3) the three carbon absorber 4) pumps, feed lines and transfer lines 5) loading racks The two process units that contain emission points affected by this modification are the recycling process, and the tank farm. The equipment and apparatus associated with the affected A - 23 ------- Proposal June 1993 emission points are pumps, feed lines, a distillation column, a condenser, a distillate receiving tank, three carbon absorber and transfer lines, and a loading rack, and storage tanks. After consulting with the permitting agency, the owner or operator will consider the three carbon absorbers and the associated emission points as one emission unit because a single control technology could be practically design to cover all three affected emission points. The owner or operator will also group the distillation column, distillate receiver and condenser into one MACT-affected emission unit. The feed lines, pumps, and transfer lines would have equipment leak emission losses and would be another affected emission unit. The owner and operator has decided to consider the emission points and equipment for the loading rack and tanks as separate MACT-affected emission units. If all the tanks were structurally similar in design one determination could be made that would be applicable to all the tanks. Step 2) Make a MACT floor finding For simplicity of this example, the MACT analysis will only be continued for a tank emission unit. All the storage tanks will be structurally similar, so only one MACT determination will be required. The manufacture has reviewed existing data bases and determined that less than 12% of tanks in the source category are controlled. Therefore the MACT floor is equal to "no control". This is not automatically an acceptable "control" A - 24 ------- Proposal June 1993 measure, so the owner or operator will move to Tier II of the MACT analysis. In Tier II of the analysis control technologies for similar emission points from outside the source category will also be considered. Tier II - Step 1 List All Available Control Technologies The following technologies have been identified as possible control technologies that can be applied to a storage tank to control working and breathing emission losses: Emission control efficiency 1. fixed-roof 86-99 2. fixed-roof plus internal floating roof 97-99 3. fixed roof vented to a carbon canister 95-100 4. fixed-roof vented to a combustion devise 99-100 5. fixed-roof vented to carbon absorber 99-100 6. pressure tank 95-99 Step 2 Eliminate Technically Infeasible Control Technologies All of the available control technologies are technically feasible. A - 25 ------- Proposal June 1993 Step 4 Conduct a Non-air Quality Health, Environmental, Economic and Energy Impacts Analysis The following charts illustrates a non-air quality health, environmental, cost and energy impacts analyses of each control option. Control Option 1 fixed roof 2 fixed roof + internal roof 3 pressure tank 4 cover and vented to carbon canister 5 cover and vent to combustion devise cover and vent to carbon absorber Secondary Air Impacts none none none emission if carbon regenerated increased CO, NOx, SOx, and particulate emissions emissions when carbon regenerated Resource Demands none none none disposal of container, solvents for regeneration fuel source, disposal of ash disposal of spent carbon, solvents for regeneration A - 26 ------- Proposal June 1993 Control Technology 1 2 3 4 5 6 Average Control Efficiency (%) 93 98 98 98 100 100 Emission Reductions (Mg/yr) 25 26 26 26 27 27 Capital Investment ($) 3790 7330 4840 5270 5790 5270 Annual Cost ($) 760 1870 3560 1020 1080 4230 Average Cost Effectiveness ($/Mg) 30 72 137 39 40 157 Incremental Cost Effectiveness ($/Mg) 1110 2800 260 60 3210 A - 27 ------- Proposal June 1993 The manufacturer will chose option 4 as the MACT candidate. Control technology 1 was eliminated because it had the lowest control efficiency and the cost, environmental, and energy considerations did not preclude the use of a control technology that obtains a greater reduction in emissions. Control technologies 2 and 3 were eliminated because control technology 4 is equally efficient in reducing emissions, but has a much lower cost than technologies 2 and 3. Technology 5 could have been a suitable candidate, but the manufacturer eliminated it due to its secondary air and energy impacts. Technology 6 has been eliminated because the capital investment and annual costs are high and there are secondary air and other impacts that are not outweighed by the emission reductions that would be obtained. The owner or operator will progress to Tier III of the analysis and determine the degree of reduction in emissions of the HAPs that can be obtained if the storage tanks are covered and vented to a carbon canister. A - 28 ------- Proposal June 1993 Appendix B Forum of Anticipated Questions 1. When computing the number of sources in the "best 12% or best 6% of similar sources in the source category" should the number of sources be rounded to the nearest or next largest whole number? For example if there are forty-five similar sources in the source category would the "best 12%" include 5 or 6 sources. The number should be rounded to the next largest number. In the example the "best 12%" would include 6 sources. 2. How many decimal points should be in the emission reduction ratio, and the manufacturer's efficiency rating? The emission reduction ratio should be carried to two decimal places. The efficiency rating should be rounded to the nearest whole number. 3. Should the emission limitation(s) be based on overall HAP emissions or emissions of an individual HAP? The emission limitation may be based on overall HAP emissions or a specific emission limitation may be specified for B - I ------- Proposal June 1993 an individual HAP. A specific emission limitation may be established if health risks warrant placing an individual emission limitation, or if an individual emission limitation is needed to make the overall HAP emission limitation federally enforceable. 4. If a major source already complies with a case-by-case MACT determination under Section 112(j) and it later proposes to constructed a new source, and emissions also increase from existing equipment or apparatus, what type of determination, if any is done for the existing equipment? If the emission increases from the new source are not greater than de minimis as defined by 40 CFR Part 63, Subpart B, the owner or operator would be require to meet a new source level of control, but would not be required to apply for any preconstruction review, unless such a review is required by the individual permitting agency. If the emissions increases are above de minimis, the construction may constitute a modification, construction or reconstruction of a major source as defined in 40 CFR Part 63, Subpart B. If this is the case, a notification of the construction or a preconstruction review may be required. 5. A non-major source undergoes a construction, reconstruction B - 2 ------- Proposal June 1993 or modification and increases emissions above a de minimis amount. This emission increase reclassifies the source as a major source for which the source category is subject to a Section 112(j) determination. What type of MACT determination would be required for the source. The entire source category at the major source would be subject to a Section 112(j) determination and would need to immediately apply for a Title V permit application reflecting a MACT emission limitation on all affected emission points within the source category. A permitting agency may also require that the owner or operator obtain a Notice of MACT Approval before the construction or reconstruction. Any emission points subject to the modification provisions of Section 112(g) would require the affected emission units to obtain a Notice of MACT Approval through the Section 112(g) process before beginning construction of the modification. 6. Must MACT always be an add-on control devise? No. MACT is a control technology which can include add-on controls, work practices, pollution prevention methods, etc 7. A major source has agreed to participate in the volunteer B - 3 ------- Proposal June 1993 emission reductions program pursuant to Section 112 (i) (5) of the Act. Through this program, an owner or operator of a major source can obtain a compliance extension for a future MACT standard, if a 90% reduction in emissions is achieved before promulgation of that relevant emission standard. Is this source subject to a Section 112 (j) MACT determination. In order to avoid a case-by-case MACT determination under Section 112 (j), the source must have obtained the required level of emission reductions by the promulgation deadline for the relevant source category. If the source has met the required level of reduction, it is still required to apply for a Title V permit to incorporate the alternate emission limitation into the permit unless such limit is already in a Title V permit. If the alternate emission limitation has not been achieved by the promulgation deadline a case-by- case MACT determination would be required under Section 8. In the course of conducting a MACT analysis for a Section 112 (j) Title V permit application, the owner or operator discovers that the MACT floor is equal to 97% control. Could the owner or operator enter the early reductions program and only obtain 90% control? B - ------- Proposal June 1993 If the promulgation deadline for a source category has been missed, the source is no longer eligible for the early reductions program. 9. If a State develops a general permit applicable to certain emission units in a source category, is an owner or operator required to apply for the general permit rather than a specific Title V permit? No. Using available information, the owner or operator could prepare an application for a specific Title V permit rather than apply for the general permit. 10. If a State has conducted a MACT analysis which is provided to the owner or operator, is the owner or operator required to use the results of this MACT analysis? Unless, the State has passed a specific State law using the MACT analysis, an owner or operator is not required to rely on the State MACT analysis. However, the owner or operator is required to prepare an application using all available information. This would require the source to use the information the State used to conduct the MACT analysis. Additional information could be added to the application, if it is publically available, accurate and reliable. B - 5 ------- Proposal June 1993 DEFINITIONS Act - the Clean Air Act as amended in 1990 (42 U.S.C. 7401 et seq.. as amended by Pub. L. 101-104 Stat. 2399). Administrator - the United States Environmental Protection Agency or his or her authorized representative (e.g a State that has been delegated the authority to implement the provisions of this part.) Affected emission point - an emission point identified as being part of a modification, construction or reconstruction and requiring a MACT determination. Alternative test method - any method of sampling and analyzing for an air pollutant that is not a test method in 40 CFR Part 63 and that has been demonstrated to the Administrator's satisfaction, using Method 301 in Appendix A of Part 63, to produce results adequate for the Administrator's determination that it may be used in place of a test method specified in that part. Approved permit program - a State permit program approved by the Administrator as meeting the requirements of 40 CFR Part 70, or a federal permit program established under 40 CFR Part 71. Controlled emissions - the sum of all hazardous air emissions from all emission points given the maximum design capacity currently in use by the emission unit taking into consideration the application of all existing control technologies and federally enforceable limits. Control technology - measures, processes method, systems, and techniques to limit the emission of hazardous air pollutants including, but not limited to, measures which (1) reduce the volume of, or eliminate emissions of, such pollutants through process changes, substitution or materials or other modifications, (2) enclose systems or processes to eliminate emissions, (3) collect, capture or treat such pollutants when released from a process, stack, storage or fugitive emissions point, (4) are design, equipment work practice, operational standards (including requirements for operator training or certification) as provided in subsection (h), or (5) are a combination of above. C - 1 ------- Proposal June 1993 Commenced - with respect to construction, reconstruction or modification of a stationary source, that an owner or operator has undertaken a continuous program of construction, reconstruction or modification or that an owner or operator has entered into a contractual obligation to undertake and complete, within a reasonable time, a continuous program of construction, reconstruction, or modification. Compliance date - the date a MACT-affected emission unit is required to be operating and meeting all the requirements of the Notice of MACT Approval. For new sources this date is upon start- up. For existing sources this date should be as soon as practicable, but no later than 3 years from the effective date, or as otherwise specified by a relevant emission standard. Construct - to fabricate (on site), erect, or install a stationary source which is or may be subject to a standard, limitation, prohibition, or other federally enforceable requirement established by the Administrator (or a State within approved permit program) pursuant to Section 112 of the Act. Continuous emission monitoring system (GEMS) - the total equipment, meeting the data acquisition and availability requirements of this part, used to sample, condition (if applicable), analyze, and provide a permanent record of emissions. Continuous monitoring system (CMS) - a continuous emission monitoring system or a continuous parameter monitoring system. Effective date - the date a Notice of MACT Approval is signed and issued by a permitting agency, or the date specified in a promulgated emission standard. Emission Unit - one emission point or the collection of emission points within a major source requiring a MACT determination. An emission unit can be defined (by the permitting authority) as any of the following: (1) An emitting point that can be individually controlled, e.g. a boiler, a spray booth, etc. (2) The smallest grouping of emission points, that, when collected together, can be commonly controlled by a single control device or work practice. (3) A grouping of emission points, that, when collected together, can be commonly controlled by a single control device or work practice. (4) A grouping of emission points that are functionally C - 2 ------- Proposal June 1993 related. Equipment is functionally related if the operation or action for which the equipment was specifically designed could not occur without being connected with or relying on the operation of another piece of equipment. (5) A grouping of emission points that, when collected together, comprise a building, structure, facility, or installation. Existing Source - a source that is not constructed or reconstructed. Federally enforceable - all limitations and conditions which are enforceable by the Administrator, including those requirements established by State or Local agencies who have received delegation to impose such limitations through an approved Part 70 permit program or through Section 112(1) of the Act. Requirements developed pursuant to Part 60 and Part 61 of this chapter and requirements within any applicable State Implementation Plan are also considered federally enforceable. To be federally enforceable, the limits and conditions must undergo public review and be reported to the EPA. Emission limits that are considered federally enforceable include limits on the allowable capacity of the equipment; requirements for the installation, operation and maintenance of pollution control technologies; limits on hours of operation; and restrictions on amounts of materials combusted, stored or produced. To be federally enforceable, restrictions on operation, production or emissions must reflect the shortest practicable time period (in no event for a period in excess of 30 days.) General limitations such as yearly limits (e.g. tons per year) are not considered federally enforceable. The use of hourly, daily, weekly, or monthly rolling averages are acceptable. Any federally enforceable limitations or conditions must be practically enforceable and ensure adequate testing, monitoring, and recordkeeping to demonstrate compliance with the limitations and conditions. Fugitive emissions - emissions from a stationary source that could not reasonably pass through a stack, chimney , vent or other functionally equivalent opening. Hazardous Air Pollutant (HAP) - any air pollutant listed in Subpart C of 40 CFR Part 63 pursuant to Section 112(b) of the Act. When there is a discrepancy between the hazardous air pollutant list in Section 112 (b) and the list in Subpart C, the list in Subpart C shall supersede the list in Section 112(b). Maximum achievable control technology fMACT) - a control technology C - 3 ------- Proposal June 1993 that achieves a maximum degree of reduction in emissions of the hazardous air pollutants with consideration to the costs of achieving such emission reductions, and the non air quality health and environmental impacts and energy requirements. MACT-affected emission unit - an emission unit or source requiring a MACT determination. MACT analysis - the process an owner/operator conducts to define the MACT floor, recommend a MACT emission limitation, and select the MACT. MACT determination - a process conducted by the Administrator to evaluate a major source's ability to comply with the requirements of 40 CFR Part 63, Subpart B. MACT emission limitation (MEL) - the maximum achievable control technology emission limitation for the hazardous air pollutants listed under Section 112(b) of the Act that the Administrator (or a State with an approved permit program) determines through a promulgated emission standard or on a case-by-case basis to be the maximum degree of reduction in emissions of the HAPs with consideration to the costs of achieving such emission reductions and the non air quality health and environmental impacts and energy requirements. If the Administrator or reviewing agency determines that it is inappropriate to prescribe a numerical or efficiency based MACT emission limitation a specific design, equipment, work practice, operational standard, or combination thereof, may be prescribed instead. Such standard shall, to the degree possible, set forth the emissions reduction achievable by implementation of such design, equipment, work practice, or operation, and shall provide for compliance by means which achieve equivalent results. MACT floor - for new sources or constructed or reconstructed major sources: a level of hazardous air pollutant emission control that is achieved in practice by the best controlled similar source as determined by the Administrator. For a existing sources or a modification to a major source the MACT floor is: (a) the average emission limitation achieved by the best performing 12 percent of existing sources (for which the Administrator has emission information), excluding those sources that have, within 18 months before the emission standard is proposed or within 30 months before such standard is promulgated, whichever is later, first achieved a level of emission rate or emission reductions C - 4 ------- Proposal June 1993 which compiles, or would comply if the source is not subject to such standard, with the lowest achievable emission rate (as defined by Section 171 of the Act) applicable to the source category and prevailing at the time, in the category or subcategory for categories and subcategories with 30 or more sources; or, (b) The average emission limitation achieved by the best performing 5 existing sources for sources with less than 30 sources in the category or subcategory. Ma-ior source - any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants, unless the Administrator establishes a lesser quantity as codified in Subpart C of 40 CFR Part 63, or in the case of radionuclides, different criteria from those specified in this sentence. Notice of MACT Approval - a document issued by a reviewing agency containing all federally enforceable conditions necessary to enforce the application of, and operation of MACT such that the MACT emission limitation is met. Owner or operator - any person who owns, leases, operates, controls, or supervises a stationary source. Part 70 permit - any permit issued, renewed, or revised pursuant to 40 CFR Part 70. Part 71 permit - any permit issued , renewed, or revised pursuant to Part 71 of this chapter. Permit program - a comprehensive State or Federal operating permit system established pursuant to regulations codified in 40 CFR Part 70 or Part 71. Permit revision - any permit modification or administrative permit amendment to a Part 70 or Part 71 permit as defined in those parts. Promulgation deadline - for each source category the date by which EPA is required to establish emission standards for the source category in accordance with Section 112(c) of the Act. These dates C - 5 ------- Proposal June 1993 are published in a regulatory schedule in the Federal Register. Potential to emit - the maximum capacity of a stationary source to emit a pollutant under its physical and operational design. Any physical or operational limitation of the capacity of the stationary source to emit a pollutant, including air pollution control equipment and restrictions on hour of operation or on the type or amount of material combusted, stored, or processed, shall be treated as part of its design if the limitation or the effect it would have on emissions is federally enforceable. Project - all activities associated with construction, reconstruction, or modification of a source including design, fabrication, erection, installation and start-up. Reconstruction - the replacement of components of an existing major source to such an extent that (1) the fixed capital cost of the new components exceeds 50 percent of the fixed capital cost that would be required to construct a comparable entirely new source, and (2) it is technologically and economically feasible for the reconstructed source to meet the Section 112(d) emission standard(s), alternative emission limitation(s), or equivalent emission limitation(s) established by the Administrator ( or a State with an approved permit program) pursuant to Section 112 of Act. Upon reconstruction, an affected source is subject to Section 112(d) standards for new sources, including compliance dates, irrespective of any change in emissions of hazardous air pollutants from that source. Relevant standard - (1) an emission standard, (2) an alternative emission standard, (3) an alternative emission limitation, (4) an equivalent emission limitation that applies to a stationary source regulated by such standard or limitation. A relevant standard may include or consist of a design, equipment work practice, or operational requirements or other measures, process, method, system or technique (including prohibition of emissions) that the Administrator (or a State with an approved permit program) determines is achievable for a constructed or reconstructed major source, new or existing source to which such standard or limitation applies. Every relevant standard established pursuant to Section 112 of the Act includes Subpart A of this part and all applicable appendices of Parts 51, 60, 61, and 63 of Chapter 40 of the code of federal regulations that are reference in that standard. Similar emission unit - two or more sources or emission units that have similar emission types and can be controlled using the same type of control technology. Similar emission type - See Section 2.4 of Chapter 2. C - 6 ------- Proposal June 1993 Source - an emission unit, or as otherwise specified in an applicable 40 CFR Part 63 emission standard. Start-up - beginning operation of a source or emission unit. State - all non-federal permitting authorities, including local agencies, interstate associations, and State-wide programs, that have delegated authority to implement (1) the provisions of 40 CFR Part 63; and/or (2) the permit program established under Part 70 of this chapter. State shall have its conventional meaning where clear from the context. Stationary source - any building, structure, facility or installation that emits or may emit any air pollutant. For the purposes of 40 CFR Part 63, stationary sources are listed in categories pursuant to Section 112(c) of the ACT and published in the Federal Register. (See Appendix D) Uncontrolled emissions - the annual sum of hazardous air pollutant emissions that could be emitted from all emission points at a source in the absence of control technologies given the maximum design capacity used by the source within the past five year period proceeding the date of the proposed construction, reconstruction or modification. C - 7 ------- Appendix D Initial List of Categories of Major and Area Sources of Hazardous Air Pollutants Fuel Combustion Category Name Engine Test Facilities Industrial Boilersb Institutional/Commercial Boilers" Process Heaters Stationary Internal Combustion Engines* Non-Ferrous Metals Processing Category Name Primary Aluminum Production Secondary Aluminum Production Primary Cooper Smelting Primary Lead Smelting Secondary Lead Smelting Lead Acid Battery Manufacturing Primary Magnesium Refining Ferrous Metals Processing Category Name Coke By-Product Plants Coke Ovens: Charging, Top Side, and Door Leaks Coke Ovens: Pushing, Quencing, and Battery Stacks Ferroalloys Production Integrated Iron and Steel Manufacturing Non-Stainless Steel Manufacturing - Electric Arc Furnace (EAF) Operation Stainless Steel Manufacturing-Electric Arc Furnace (EAF) Operation Iron Foundries Steel Foundries Steel Pickling-HCI Process Mineral Products Processing Category Name Alumina Processing Asphalt/Coal Tar Application-Metal Pipes Asphalt Concrete Manufacturing Asphalt Processing Asphalt Roofing Manufacturing Chromium Refractories Production Clay Products Manufacturing D-l ------- Lime Manufacturing Mineral Wood Production Portland Cement Manufacturing Taconite Iron Ore Processing Wool Fiberglass Manufacturing Petroleum and Natural Gas Production and Refining Category Name Oil and Natural Gas Production Petroleum Refineries-Catalytic Cracking (Fluid and other) Units, Catalytic Reforming Units, and Sulfur Plant Units Petroleum Refineries-Other Sources Not Distinctly Listed Liquids Distribution Category Name Gasoline Distribution (Stage 1) Organic Liquids Distribution (Non-Gasoline) Surface Coating Processes Category Name Aerospace Industries Auto and Light Duty Truck (Surface Coating) Flat Woods Paneling (Surface Coating) Large Appliances (Surface Coating) Magnetic Tapes (Surface Coating) Manufacture of Paints Coatings, and Adhesives Metal Can (Surface Coating) Metal Coil (Surface Coating) Metal Furniture (Surface Coating) Miscellaneous Metal Parts and Products (Surface Coating) Paper and Other Webs (Surface Coating) Plastic Parts and Products (Surface Coating) Printing Coating, and Dyeing of Fabrics Printing/Publishing (Surface Coating) Shipbuilding and Ship Repair (Surface Coating) Wood Furniture (Surface Coating) Waste Treatment and Disposal Category Name Hazardous Waste Incineration Municipal Landfills Sewage Sludge Incineration Site Remediation D-2 ------- Solid Waste Treatment, Storage and Disposal Facilities (TSDF) Publicly Owned Treatment Works (POTW) Emissions Agricultural Chemicals Production Category Name 2.4-D Salts and Esters Production 4-Chloro-2-Methylphenoxyacetic Acid Production 4.6-Dinitro-o-Cresol Production Captafol Production Captan Production Chloroneb Production Chlorothalonil Production Dacthal (tm) Production Sodium Pentachlorophenate Production Tordon (tm) Acid Production Fibers Production Processes Category Name Acrylic Fibers/Modacrylic Fibers Production Rayon Production Spandex Production Food and Agricultural Processes Category Name Baker's Yeast Manufacturing Cellulose Food Casing Manufacturing Vegetable Oil Production Pharmaceutical Production Processes Category Name Pharmaceutical Production Polymers and Resins Production Category Name Acetal Resins Production Acrylonitrile-Butadiene-Styrene Production Alkyd Resins Production Amino Resins Production Boat Manufacturing Butadiene-Furfural Cotrimer (R-ll) Butyl Rubber Production Carboxymethylcellulose Production Cellophane Production Cellulose Ethers Production Epichlorohydrin Elastomers Production Epoxy Resins Production D-3 ------- Ethylene-Propylene Elastomers Production Flexible Polyurethane Foam Production Hypalon (tm) Production Maleic Anhydride Copolymers Production Methylcellulose Production Methylcellulose Production Methyl Methacrylate-Acrylonitrile-Butadiene- Styrene Production Methyl Methacrylate-Butadiene-Styrene Terpolymers Production Neoprene Production Nitrile Butadiene Rubber Production Non-Nylon Polyamides Production Nylon 6 Production Phenolic Resins Production Polybutadiene Rubber Production Polycarbonates Production Polyester Resins Production Polyethylene Teraphthalate Production Polymerized Vinylidene Chloride Production Polymethyl Methacrylate Resins Production Polystyrene Production Polysulfide Rubber Production Polyvinyl Acetate Emulsions Production Polyvinyl Alcohol Production Polyvinyl Butyral Production Polyvinyl Chloride and Copolymers Production Reinforced Plastic Composites Production Styrene-Acrylonitrile Production Styrene-Butadiene Rubber and Latex Production Production of Inorganic Chemicals Category Name Ammonium Sulfate Production-Captrolactam By-Product Plants Antimony Oxides Manufacturing Chlorine Production Chromium Chemicals Manufacturing Cyanuric Chloride Production Fume Silica Production Hydrochloric Acid Production Hydrogen Cyanide Production Hydrogen Fluoride Production Phosphate Fertilizers Production Phosphoric Acid Manufacturing Quaternary Ammonium Compounds Production Sodium Cyanide Production Uranium Hexafluoride Production D-4 ------- Production of Organic Chemicals Category Name Synthetic Organic Chemical Manufacturing Miscellaneous Processes Category Name Aerosol Can-Filling Facilities Benzyltrimethylammonium Chloride Production Butadiene Dimers Production Carbonyl Sulfide Production Chelating Agents Production Chlorinated Paraffins Production Chromic Acid Anodizing Commercial Dry Cleaning (Perchloroethylene) Transfer Machines Commercial Sterilization Facilities Decorative Chromium Electroplating Dodencanedioic Acid Production Dry Cleaning (Petroleum Solvent) Ethylidene Norbornene Production Explosives Production Halogenated Solvent Cleaners Hard Chromium Electroplating Hydrazine Production Industrial Dry Cleaning (Perchloroethylene) Transfer Machines Industrial Dry Cleaning (Perchloroethylene) Dry-to-Dry Machines Industrial Process Cooling Towers OBPA/1,3-Diisocyanate Production Paint Stripper Users Photographic Chemicals Production Phthalate Plasticizers Production Plywood/Particle Board Manufacturing Polyether Polyols Production Pulp and Paper Production Rocket Engine Test Firing Rubber Chemicals Manufacturing Semiconductor Manufacturing Symmetrical Tetrachloropyridine Production Tire Production Wood Treatment D-5 ------- |