_______________________________________________________________________ Part V Environmental Protection Agency _______________________________________________________________________ 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutants for Certain Source Categories; Final Rule ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 [AD-FRL 4846-2] RIN 2060-AC 19 National Emission Standards for Hazardous Air Pollutants for Source Categories; Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry and Other Processes Subject to the Negotiated Regulation for Equipment Leaks AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. ----------------------------------------------------------------------- SUMMARY: On December 31, 1992, the EPA proposed to regulate the emissions of certain organic hazardous air pollutants from synthetic organic chemical manufacturing industry (SOCMI) production processes which are part of major sources under section 112 of the Clean Air Act as amended in 1990 (the Act). This Federal Register action announces the EPA's final decisions on the rule which is referred to as the hazardous organic NESHAP or the HON. The HON requires sources to achieve emission limits reflecting the application of the maximum achievable control technology consistent with sections 112(d) and 112(h) of the Act. The rule regulates the emissions of 112 of the organic chemicals identified in the Act's list of 189 hazardous air pollutants at both new and existing SOCMI sources and from equipment leaks at sources in certain polymer and resin production processes, certain pesticide production processes, and certain miscellaneous processes as described in the Source Category Schedule for Standards (58 FR 63941). The EPA is also finalizing Methods 304 and 305 with the standard. These methods can be used to demonstrate compliance with control requirements for wastewater streams. EFFECTIVE DATE: April 22, 1994. The incorporation by reference of certain publications in these standards is approved by the Director of the Office of the Federal Register as of April 22, 1994. The information collection requirements contained in 40 CFR Part 63 subparts F, G, H, and I have not been approved by the Office of Management and Budget (OMB) and are not effective until OMB has approved them. See Supplementary Information section concerning judicial review. ADDRESSES: Dockets. The following dockets contain supporting information used in developing the proposed rule. Docket Number A-90-19 contains information specific to process vents, emissions averaging and general information used to characterize emissions and control costs for the industry; Docket A-90-20 contains information on equipment leaks; Docket A-90-21 contains information on storage vessels; Docket A-90-22 contains information on transfer operations; and Docket A-90-23 contains information specific to wastewater operations. Supporting information used in developing the negotiated standard for equipment leaks is available in Docket Number A-89-10. These dockets are available for public inspection and copying between 8 a.m. and 4 p.m., Monday through Friday, at the EPA's Air and Radiation Docket and Information Center (formerly known as the Air Docket), room M1500, U. S. Environmental Protection Agency, 401 M Street, SW., Washington, DC 20460. A reasonable fee may be charged for copying. FOR FURTHER INFORMATION CONTACT: Dr. Janet S. Meyer, Standards Development Branch, Emission Standards Division (MD-13), U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, telephone number (919) 541-5299. SUPPLEMENTARY INFORMATION: Under section 307(b)(1) of the Act, judicial review of NESHAP is available only by filing a petition for review in the United States Court of Appeals for the District of Columbia Circuit within 60 days of today's publication of this rule. Under section 307(b)(2) of the Act, the requirements that are the subject of today's notice may not be challenged later in civil or criminal proceedings brought by the EPA to enforce these requirements. The following outline is provided to aid in reading the preamble to the standards. I. Definitions, Acronyms, and Abbreviations A. Definitions B. Acronyms C. Abbreviations II. Background A. Development of Hazardous Organic NESHAP and Public Participation B. Previous Federal Register Citations and Background Documents C. Statutory Requirements for NESHAP III. Summary of Promulgated Rule and Significant Changes A. Summary of Subpart F B. Summary of Subpart G C. Summary of Subpart H D. Summary of Subpart I IV. Impacts A. Environmental Impacts B. Energy Impacts C. Cost Impacts D. Economic Impacts V. Summary of Significant Comments and Associated Changes to the Proposed Subparts F and G A. Selection of Source Category and Source B. Selection of Pollutants C. Selection of the Rule D. Emissions Averaging E. Compliance, Recordkeeping, and Reporting F. Coordination with Other Clean Air Act Requirements G. Miscellaneous Technical Comments VI. Summary of Significant Comments and Changes to Proposed Subpart H A. Applicability B. Compliance Schedule C. Selection of Requirements D. Recordkeeping and Reporting VII. Administrative requirements A. Docket B. Executive Order 12866 C. Paperwork Reduction Act D. Regulatory Flexibility Act E. Review I. Definitions, Acronyms, and Abbreviations The following lists of definitions, acronyms, and abbreviations for units of measure are provided to aid in reading the preamble to the final rule. Additional definitions are provided near the beginning of subparts F, G, H, and I. A. Definitions The following definitions were developed for use in preparing and describing the final rule. Control device means any equipment used for recovering or oxidizing organic hazardous air pollutant vapors. Such equipment includes, but is not limited to, absorbers, carbon adsorbers, condensers, incinerators, flares, boilers, and process heaters. For process vents, recovery devices are not considered control devices. Discount factor is a specified percentage used to reduce the value of emission credits. A discount factor of 10 percent reduces 10 Mg of potential emission credits to 9 Mg of actual emission credits that could be used to balance an emissions debit. For regulatory purposes, a 10 percent discount factor is represented as 0.9 in credit estimation equations. Emissions averaging is a means of complying with subpart G of part 63 at existing sources. Emissions averaging allows a source to create emission credits by reducing emissions from specific points to a level below that required by subpart G. Those credits are used to offset emission debits from points that are not controlled to the level required by subpart G. Emission credits are excess emission reductions above those required by subpart G that are used to offset emission debits in emissions averaging. Emission debits are increased emissions that result when a source elects not to control a Group 1 emission point to the level required by subpart G. Emission point means an individual process vent, storage vessel, transfer rack, wastewater stream, or equipment leak. Group 1 emission point means an individual process vent, storage vessel, transfer rack, or wastewater stream that satisfies the applicability criteria for the control requirements of subpart G. Group 2 emission point means an individual process vent, storage vessel, transfer rack, or wastewater stream that does not satisfy the applicability criteria for the control requirements of subpart G. Halogenated vent stream or halogenated stream means a vent stream from a process vent or transfer operation determined to have a mass emission rate of halogen atoms contained in organic compounds of 0.45 kilograms per hour or greater. Hazardous Air Pollutant or HAP means any air pollutant listed under section 112(b) of the Act. Plant site means all contiguous or adjoining property that is under common control, including properties that are separated only by a road or other public right-of-way. Common control includes properties that are owned, leased, or operated by the same entity, parent entity, subsidiary, or any combination thereof. Reference control technology means a device or devices that can be used to comply with the control requirements in subpart G. Subpart G specifies the reference control technologies for each kind of emission point and establishes a control efficiency that the devices should achieve when being used to comply with this rule. Very volatile hazardous air pollutant or very volatile HAP means one of the chemicals listed in table 8 of subpart G. Volatile organic concentration or VO concentration refers to the concentration of organic compounds (including both hazardous air pollutant and nonhazardous air pollutant organic compounds) in a wastewater stream that is measured by Method 25D, as found in 40 CFR 60, appendix A. Volatile organic hazardous air pollutant concentration or VOHAP concentration means the concentration of an individually-speciated organic hazardous air pollutant in a wastewater stream or a residual that is measured by proposed Method 305. Waste management unit means any component, piece of equipment, structure, or transport mechanism used in conveying, storing, treating, or disposing of any waste, including a wastewater stream or a residual. Wastewater tanks are an example of a waste management unit. Wastewater means organic hazardous air pollutant-containing water, raw material, intermediate, product, by- product, co-product, or waste material that is discharged into an individual drain system and either: (1) contains a concentration of at least 5 parts per million by weight total organic hazardous air pollutant and has a flow rate of 0.02 liter per minute or greater; or (2) contains a concentration of at least 10,000 parts per million by weight total organic hazardous air pollutant at any flow rate. Wastewater includes process wastewater and maintenance wastewater. B. Acronyms ------------------------------------------------------------------------ Acronym Term ------------------------------------------------------------------------ Act....... Clean Air Act. ALAPCO.... Association of Local Air Pollution Control Officers. ASPEN..... Advanced system for process engineering. BACT...... Best available control technology. BAT....... Best available technology. BD........ Butadiene. BID....... Background information document. BIF....... Boilers and industrial furnaces. CEM....... Continuous emissions monitoring. CFR....... Code of Federal Regulations. CMA....... Chemical Manufacturers Association. CMPU...... Chemical manufacturing process unit. CO........ Carbon monoxide. CTG....... Control techniques guideline. CWA....... Clean Water Act. DMS....... Dual mechanical seal. DOT....... Department of Transportation. DRE....... Destruction and removal efficiency. EB/S...... Ethylbenzene/styrene. EDC....... Ethylene dichloride. EFR....... External floating roof. EO........ Ethylene oxide. E.O....... Executive Order. EPA....... Environmental Protection Agency. Fe........ Fraction emitted. Fm........ Fraction measured. FR........ Federal Register. Fr........ Fraction removed. FTIR...... Fourier transform infrared. HAP....... Hazardous air pollutant. HON....... Hazardous organic national emission standards for hazardous air pollutants. IFR....... Internal floating roof. LDAR...... Leak detection and repair. LAER...... Lowest achievable emission rate. MACT...... Maximum achievable control technology. MIBK...... Methyl isobutyl ketone. MR........ Mass removal (actual). NCS....... Notification of Compliance Status. NESHAP.... National emission standards for hazardous air pollutants. NOX....... Nitrogen oxides. NPDES..... National Pollutant Discharge Elimination System. NRDC...... Natural Resources Defense Council. NSPS...... New source performance standards. NSR....... New source review. OCCM...... Office of Air Quality Planning and Standards Control Cost Manual. OCPSF..... Organic chemicals, plastics, and synthetic fibers. OMB....... Office of Management and Budget. OSHA...... Occupational Safety and Health Administration. P.L....... Public Law. PAV....... Product accumulator vessel. POM....... Polycyclic organic matter. POTW...... Publicly owned treatment works. PRA....... Paperwork Reduction Act. PRV....... Pressure relief valve. PSD....... Prevention of significant deterioration. QIP....... Quality improvement program. R&D....... Research and development. RCRA...... Resource Conservation and Recovery Act. RCT....... Reference control technology. RIA....... Regulatory Impact Analysis. RMR....... Required mass removal. SARA...... Superfund Amendment and Reauthorization Act. SIP....... State Implementation Plan. SMS....... Single mechanical seal. SOCMI..... Synthetic organic chemical manufacturing industry. STAPPA.... State and Territorial Air Pollution Program Administrators. TAC....... Total annual cost. TACB...... Texas Air Control Board. TCI....... Total capital investment. THC....... Total hydrocarbon. TIC....... Total industry control. TOC....... Total organic compound. TRE....... Total resource effectiveness. TRI....... Toxics release inventory. TSDF...... Treatment, storage, and disposal facility. VHAP...... Volatile hazardous air pollutant. VO........ Volatile organics measurable by Method 25D. VOC....... Volatile organic compound. VOHAP..... Volatile organic hazardous air pollutant. ------------------------------------------------------------------------ C. Abbreviations ------------------------------------------------------------------------ Abbreviation Unit of measure ------------------------------------------------------------------------ bbl............. Barrel. BOE............. Barrels of oil equivalent. Btu............. British thermal unit. Btu/kW-hr....... British thermal unit per kilowatt-hour. deg.C.......... Degrees Celsius. deg.F.......... Degrees Fahrenheit. gal............. Gallon. gpm............. Gallons per minute. hr.............. Hour. kg/hr........... Kilograms per hour. kPa............. Kilopascals. kW-hr/yr........ Kilowatt-hour per year. l/hourm2 Liters per hour per square meter. lpm............. Liters per minute. gal............. Gallons. m3.............. Cubic meters. Mg.............. Megagrams. mg.............. Milligrams. mg/dscm......... Milligram per dry standard cubic meter. MW.............. Megawatts. ppb............. Parts per billion. ppm............. Parts per million. ppmv............ Parts per million by volume. ppmw............ Parts per million by weight. psia............ Pounds per square inch absolute. scm/min......... Standard cubic meter per minute. TJ.............. Terajoules. yr.............. Year. ------------------------------------------------------------------------ II. Background A. Development of Hazardous Organic NESHAP and Public Participation On December 31, 1992, the EPA proposed to regulate, under section 112 of the Act, the emissions of 112 organic HAP's from SOCMI processes which are part of major sources. Following publication of the proposed rule, two public hearings were held and 339 written comments were received regarding the proposed rule. The EPA considered all public comments and made appropriate changes to the provisions. The final rule issued today represents the EPA's final decisions for the MACT standard for the SOCMI. A background information document summarizing and responding to legal comments and technical comments pertaining to this rulemaking may be obtained from either: (1) The National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161, telephone (703) 487-4650, or (2) the EPA Technology Transfer Network (TTN). The TTN is an electronic bulletin board system which is free, except for the normal long distance charges. To access the HON BID: (1) Set software to data bits: 8, N; stop bits: 1; (2) Use access number (919) 541-5742 for 1200, 2400, or 9600 bps modems [access problems should be directed to the system operator at (919) 541-5384]; (3) Specify TTN Bulletin Board: Clean Air Act Amendments; and (4) Select menu item: Recently Signed Rules. Please refer to ``Hazardous Air Pollutant Emissions from Process Units in the Synthetic Organic Chemical Manufacturing Industry-- Background Information for Promulgated Standards,'' and specify volume number(s). Volume 2A: Comments on Process Vents, Storage Vessels, Transfer Operations, and Equipment Leaks (EPA-453/R-94-003a); Volume 2B: Comments on Wastewater (EPA-453/R-94-003b); Volume 2C: Comments on Emissions Averaging (EPA-453/R-94- 003c); Volume 2D: Comments on Applicability, National Impacts, and Overlap with Other Rules (EPA-453/R-94-003d); Volume 2E: Comments on Recordkeeping, Reporting, Compliance, and Test Methods (EPA-453/R-94-003e); and Volume 2F: Commenter Identification List (EPA-453/R-94- 003f). B. Previous Federal Register Citations and Background Documents Previous Federal Register Notices. Previous Federal Register notices pertaining to this rulemaking are listed below in chronological order. Since the complete Federal Register citation and dates are listed here, they will not be repeated throughout this notice. Where appropriate, an abbreviated descriptive title used to refer to the document throughout this notice is also listed. (1) ``National Emission Standards for Hazardous Air Pollutants for Source Categories: Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry and Seven Other Processes; Proposed rule and notice of public hearing,'' 57 FR 62608, December 31, 1992. Proposal notice. (2) ``National Emission Standards for Hazardous Air Pollutants for Source Categories: Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry and Seven Other Processes; Correction,'' 58 FR 11667, February 26, 1993. Correction notice. (3) ``National Emission Standards for Hazardous Air Pollutants for Source Categories: Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry and Seven Other Processes; Reopening of public comment period and correction to Regulatory Flexibility Act certification,'' 58 FR 53478, October 15, 1993. Supplemental notice. Previous Background Documents. The following is a listing of background documents pertaining to this rulemaking. The complete title, EPA publication number, publication date, and National Technical Information Service [NTIS] numbers are included. Where appropriate, an abbreviated descriptive title used to refer to the document throughout this notice is also listed. (1) ``Hazardous Air Pollutant Emissions from Process Units in the Synthetic Organic Chemical Manufacturing Industry--Background Information for Proposed Standards, Volume 1A: National Impacts Assessment,'' EPA-453/D-92-016a. November 1992. (NTIS Number PB93- 156552) (Docket item A-90-19: III-B-1). Proposal BID Volume 1A. (2) ``Hazardous Air Pollutant Emissions from Process Units in the Synthetic Organic Chemical Manufacturing Industry--Background Information for Proposed Standards, Volume 1B: Control Technologies,'' EPA-453/D-92-016b. November 1992. (NTIS Number PB93-156560) (Docket Item A-90-19: III-B-1). Proposal BID Volume 1B. (3) ``Hazardous Air Pollutant Emissions from Process Units in the Synthetic Organic Chemical Manufacturing Industry--Background Information for Proposed Standards, Volume 1C: Model Emission Sources,'' EPA-453/D-92-016c. November 1992. (NTIS Number PB93-156578) (Docket item A-90-19: III-B-1). Proposal BID Volume 1C. C. Statutory Requirements for NESHAP Section 112 of the Act requires that the EPA establish regulations setting emission standards for categories of sources of HAP emissions. In addition, the Act sets out specific criteria for establishing a minimum level of control, and criteria to be considered in evaluating control options more stringent than the minimum control level. For most of these rules, assessment and control of any remaining unacceptable health risk is to occur 8 years after they are promulgated. However, for the rules required to be promulgated in the first 2 years after enactment, EPA is not required to conduct this assessment until 9 years after promulgation. Specifically, section 112(c), as amended, directs the Administrator to develop a list of all categories or subcategories of major sources and such categories or subcategories of area sources that meet the requirements of section 112(c)(3), emitting any of the HAP's listed in section 112(b). Section 112(d) directs the Administrator to promulgate emission standards for each listed category or subcategory of HAP sources. Such standards will be applicable to both new and existing sources and shall require: * * * the maximum degree of reduction in emissions of the hazardous air pollutants subject to this section (including a prohibition on such emissions, where achievable) that the Administrator, taking into consideration the cost of achieving such emission reduction, and any non-air quality health and environmental impacts and energy requirements, determines is achievable for new and existing sources in the category or subcategory to which such emission standard applies * * * 42 U.S.C. 7412(d)(2). The Amendments further provide that ``the maximum degree of reduction in emissions that is deemed achievable'' shall be subject to a ``floor'' which is determined differently for new and existing sources. For new sources the standards set shall not be any less stringent than ``the emission control that is achieved in practice by the best controlled similar source.'' For existing sources, the standards may not be less stringent than the average emission limitation achieved by the best performing 12 percent of existing sources in each category or subcategory of 30 or more sources. (Smaller categories or subcategories are limited to the average of the best performing five sources in the category or subcategory.) III. Summary of Promulgated Rule and Significant Changes This section of the notice summarizes the final rule and significant changes made in response to public comment. The rationale for specific provisions and changes is explained in sections V and VI. The rule consists of four subparts in 40 CFR part 63. Subpart F provides the applicability criteria for SOCMI sources, requires that owners and operators of SOCMI sources comply with subparts G and H, and specifies general recordkeeping and reporting requirements. The specific control, monitoring, reporting, and recordkeeping requirements are stated in subpart G for process vents, storage vessels, transfer racks, and wastewater streams, and in subpart H for equipment leaks. Subpart I provides the applicability criteria for the non-SOCMI processes subject to the negotiated regulation for equipment leaks and requires owners and operators to comply with subpart H. A. Summary of Subpart F Subpart F lists the HAP's regulated by this rule and specifies what is included in the SOCMI source category and thus subject to the requirements in subparts F, G, and H. In the final rule, the EPA has revised the procedures for determining applicability to more clearly indicate the boundaries between processes (i.e., where one process ends and the next begins). In addition, subpart F presents definitions and general information on compliance, reporting, and recordkeeping requirements that are applicable for sources subject to subparts G and H. 1. Regulated Pollutants Subpart F lists 112 organic HAP's that the EPA has determined may be emitted from SOCMI processes because they are either produced as a product or used as a reactant. The emissions of these 112 organic chemicals are regulated by subparts F, G, and H. 2. Definition of Source Category and Source The rule applies to chemical manufacturing process units that are: (1) Part of a major source as defined in section 112 of the Act; (2) produce as a primary product a SOCMI chemical listed in table 1 of subpart F; and (3) use as a reactant or manufacture as a product, by- product, or co-product one or more of the organic HAP's listed in table 2 of subpart F. A chemical manufacturing process unit is subject to the provisions of subparts F, G, and H only if all of the above three conditions are satisfied. Table 1 of subpart F is a list of 385 chemicals which defines SOCMI products that may be produced by a HAP- emitting process. For the SOCMI source category, a source comprises all the SOCMI chemical manufacturing process units that are subject to the rule and are located at contiguous or adjoining properties under common control. Subpart F defines the SOCMI source as the collection of process vents; storage vessels; transfer racks; wastewater and the associated treatment residuals; and pumps, compressors, agitators, pressure relief devices, sampling connection systems, open-ended valves or lines, valves, connectors, and instrumentation systems in the relevant chemical manufacturing process units. As listed above, the first four kinds of emission points in a SOCMI source are subject to subparts F and G. However, SOCMI equipment leaks are subject to subparts F and H. As such, a SOCMI source is subject to three of the HON's four subparts. 3. Other Provisions Subpart F establishes the compliance dates for new and existing sources and requires the source be properly operated and maintained at all times. Sources are required to develop a start-up, shutdown, and malfunction plan which includes a description of procedures for managing wastewaters generated during maintenance. Monitoring of cooling water is also required to detect leaks in heat exchange equipment. If a leak is detected, the heat exchanger must be repaired or taken out of service. Procedures for obtaining permission to use an alternative means of emission reduction are included in subpart F. The applicability of the General Provisions in subpart A to sources subject to subparts F, G, and H is clarified. General performance test requirements are specified, including the provision that performance tests be conducted under maximum representative operating conditions for the process. The General Reporting and Recordkeeping Provisions of subpart F include the requirement that required records and reports must be maintained for 5 years, and specify where reports must be sent. Reports can be submitted on electronic media that are compatible with the system used by the Administrator or the State permitting authority. B. Summary of Subpart G 1. Overview The MACT standard for SOCMI sources is expressed as an allowable emissions level that is determined by means of an equation specified in subpart G. The allowable emissions level is the sum of the emissions from all the emission points in the source that would occur after the required emission reductions are achieved for the emission points meeting the HON's applicability criteria (Group 1 points) through use of reference control technologies. Although controls are not required for Group 2 emission points, both Group 1 emission points and Group 2 emission points are included in the equation defining the source's allowable emissions level. Though subpart G is structured as an allowable emissions level, there is no need for owners or operators to actually calculate emissions estimates for every emission point at the source. Actual emissions estimates are only required for emission points that are included in emissions averages. The owner or operator can utilize two methods, or a combination of them, to demonstrate compliance with the HON. The primary method that owners or operators will use to determine compliance with the HON is the application of the reference control technologies (or equivalent controls) at Group 1 emission points. This compliance approach is described in sections 2 through 5 below. Owners or operators may also use emissions averaging to demonstrate compliance at a limited number of emission points. Emissions averaging is described in section 6 below. Section 7 describes the HON's recordkeeping and reporting provisions. 2. Process Vent Provisions A process vent means a gas stream that is continuously discharged during the operation of the unit from an air oxidation reactor, other reactor, or distillation unit within a SOCMI chemical manufacturing process unit. Process vents include vents from distillate receivers and product separators. Process vents include gas streams that are discharged directly to the atmosphere and gas streams discharged to the atmosphere after diversion through a product recovery device. The rule applies only to process vents that are associated with continuous (non- batch) processes and emit process vent streams containing more than 0.005 weight-percent HAP. A Group 1 process vent is defined as a process vent with a flow rate greater than or equal to 0.005 scmm, an organic HAP concentration greater than or equal to 50 ppmv, and a TRE index value less than or equal to 1.0. The process vent provisions require the owner or operator of a Group 1 process vent stream to: (1) Reduce the emissions of organic HAP using a flare; (2) Reduce emissions of organic HAP by 98 weight-percent or to a concentration of 20 ppmv or less; or (3) Achieve and maintain a TRE index above 1. Performance test provisions are included for Group 1 process vents to verify that the control device achieves the required performance. The organic HAP reduction is based on the level of control achieved by the reference control technology. Group 2 process vent streams with TRE index values between 1.0 and 4.0 are required to monitor those process vent streams to ensure those streams do not become Group 1, which require control. The owner or operator can calculate a TRE index value to determine whether each process vent is a Group 1 or Group 2 process vent or the owner or operator can elect to comply directly with the control requirements without calculating the TRE index. The TRE index value is determined after the final recovery device in the process or prior to venting to the atmosphere. The TRE calculation involves an emissions test or engineering assessment and use of the TRE equations in section 63.115 of subpart G. The rule encourages pollution prevention through product recovery because an owner or operator of a Group 1 process vent may add recovery devices or otherwise reduce emissions to the extent that the TRE becomes greater than 1.0 and the Group 1 process vent becomes a Group 2 process vent. Group 1 halogenated streams controlled using a combustion device must vent the emissions from the combustor to an acid gas scrubber or other device to limit emissions of halogens prior to venting to the atmosphere. The control device must reduce the overall emissions of hydrogen halides and halogens by 99 percent (95 percent for control devices installed prior to the December 31, 1992 proposal) or reduce the outlet mass emission rate of total hydrogen halides and halogens to less than 0.45 kg/hr. Monitoring, reporting, and recordkeeping provisions necessary to demonstrate compliance are also included in the process vent provisions. 3. Storage Vessel Provisions A storage vessel means a tank or other vessel associated with a SOCMI chemical manufacturing process unit that stores a liquid containing one or more of the organic HAP's listed in table 2 of subpart F. The final rule specifies assignment procedures for determining whether a storage vessel is associated with a SOCMI chemical manufacturing process unit. The storage vessel provisions do not apply to the following: (1) vessels permanently attached to motor vehicles, (2) pressure vessels designed to operate in excess of 204.9 Kpa (29.7 psia), (3) vessels with capacities smaller than 38 m\3\ (10,000 gal), (4) wastewater tanks, and (5) vessels storing liquids that contain organic HAP's only as impurities. An impurity is produced coincidentally with another chemical substance and is processed, used, or distributed with it. The EPA is not taking final action at this time regarding provisions for storage vessels of 76 m\3\ (20,000 gallons) to 151 m\3\ (40,000 gallons). The reason is that, through a separate Federal Register notice, the EPA is soliciting additional public comment regarding the appropriate interpretation of the language in section 112(d)(3)(A) of the Act concerning establishment of the MACT floor and the effect of that interpretation on the control requirements for these storage vessels. The EPA intends to evaluate the public comments received in response to that action promptly and intends to proceed to take final action on provisions for storage vessels of 76 m\3\ to 151 m\3\ within 90 days of the publication of the separate notice. The storage provisions require that one of the following control systems be applied to Group 1 storage vessels: (1) An internal floating roof with proper seals and fittings; (2) an external floating roof with proper seals and fittings; (3) an external floating roof converted to an internal floating roof with proper seals and fittings; or (4) a closed vent system with a 95-percent efficient control device. The storage provisions give details on the types of seals and fittings required. Monitoring and compliance provisions include periodic visual inspections of vessels, roof seals, and fittings, as well as internal inspections. If a closed vent system and control device is used, the owner or operator must establish appropriate monitoring procedures. Reports and records of inspections, repairs, and other information necessary to determine compliance are also required by the storage provisions. No controls are required for Group 2 storage vessels. 4. Transfer Operations Provisions Transfer operations are defined as the loading of liquid products that are on the list of organic HAP's in subpart F from a transfer rack into a tank truck or railcar. Transfer rack means the collection of loading arms and loading hoses at a single system that is assigned to a SOCMI chemical manufacturing process unit and is used to fill tank trucks and railcars with liquid products that are on the list of organic HAP's in subpart F. Transfer rack includes the associated pumps, meters, shutoff valves, relief valves, and other piping and valves necessary to load tank trucks or railcars. The transfer provisions do not apply to the loading of liquid organic HAP's at an operating pressure in excess of 204.9 Kpa (29.7 psia); loading of marine vessels; racks loading liquids that contain organic HAP's only as impurities; or racks loading liquid organic HAP's if emissions are returned to a storage vessel in a vapor balancing system. The transfer provisions require control of Group 1 transfer racks to achieve 98-percent organic HAP reduction or an outlet concentration of 20 ppmv. Combustion devices or product recovery devices may be used to comply with this requirement. Alternatively, vapor balancing systems may be used. The transfer provisions include design specifications for vapor collection systems. Specifically, vapor collection systems are required to route the organic vapors to a control device or to a vapor balancing system and are required to operate without detectable emissions. In addition, the provisions require that liquid organic HAP's be loaded only into DOT-certified vehicles or vehicles that have been determined to be vapor tight according to Method 27 of 40 CFR part 60, appendix A. Group 1 halogenated streams controlled using a combustion device must vent the emissions from the combustor to an acid gas scrubber or other device to limit emissions of halogens, prior to venting to the atmosphere. The control device must reduce the overall emissions of hydrogen halides and halogens by 99 percent or reduce the outlet mass emission rate of total hydrogen halides and halogens to less than 0.45 kg/hr. Initial performance tests of control device efficiency are required for racks loading at least 11.8 million liters per year. Design evaluations are allowed in other cases. Monitoring, reporting, and recordkeeping provisions are specified. Controls are not required for Group 2 racks. 5. Wastewater Provisions The final rule applies to any organic HAP-containing water, raw material, intermediate, product, by-product, co- product, or waste material that exits any chemical manufacturing process unit equipment and has either (1) a total volatile organic HAP concentration of 5 ppmw or greater and a flow rate of 0.02 lpm or greater; or (2) a total volatile organic HAP concentration of 10,000 ppmw or greater at any flow rate. ``Wastewater,'' as defined in Sec. 63.101 of subpart F, encompasses both maintenance wastewater, which is regulated by subpart F, and process wastewater, which is regulated by subpart G. The process wastewater provisions in subpart G also apply to organic HAP-containing residuals that are generated from the management and treatment of Group 1 wastewater streams. Examples of process wastewater streams include, but are not limited to, wastewater streams exiting process unit equipment (e.g., decanter water, such as condensed steam used in the process), product tank drawdown, feed tank drawdown, and residuals recovered from waste management units. Examples of maintenance wastewater streams are those generated by descaling of heat exchanger tubing bundles, cleaning of distillation column traps, and draining of pumps into an individual drain system. In the final rule, an owner or operator may determine the VOHAP concentration and flow rate of a wastewater stream either (1) at the point of generation; or (2) downstream of the point of generation. If wastewater stream characteristics are determined downstream of the point of generation, an owner or operator must make corrections for losses by air emissions; reduction of VOHAP concentration or changes in flow rate by mixing with other water or wastewater streams; and reduction in flow rate or VOHAP concentration by treating or otherwise handling the wastewater stream to remove or destroy HAP's. An owner or operator must determine whether a wastewater stream is a Group 1 or Group 2 wastewater stream by determining the flow rate and VOHAP concentration for the point of generation by (1) sampling; (2) using engineering knowledge; or (3) using pilot-scale or bench-scale test data. An owner or operator who elects to use the process unit alternative in Sec. 63.138(d) or the 95-percent biological treatment option in Sec. 63.138(e) is not required to make a Group 1/Group 2 determination. Both the applicability determination and the Group 1/ Group 2 determination must reflect the wastewater characteristics before losses due to volatilization, a concentration differential due to dilution, or a change in VOHAP concentration or flow rate due to treatment. To provide greater flexibility to owners or operators, the EPA has added to the final rule an additional option in Sec. 63.144 of subpart G for determining applicability in lieu of a Group 1/Group 2 determination. This option allows an owner or operator to designate a wastewater stream or mixture of wastewater streams to be a Group 1 wastewater stream without actually determining the flow rate and VOHAP concentration for the point of generation. This option helps those SOCMI plants that already have emission suppression systems in place from the point of generation to a location downstream. Using this option, an owner or operator can simply declare that a wastewater stream or mixture of wastewater streams is a Group 1 wastewater stream and that the emissions from the stream(s) are controlled from the point of generation through treatment. An owner or operator is required to determine the wastewater stream characteristics (i.e., VOHAP concentration and flow rate) for the designated Group 1 wastewater stream in order to establish the treatment requirements in Sec. 63.138. Controls must be applied to Group 1 wastewater streams, unless the source complies with the source-wide mass flow rate provisions of Sec. 63.138(c)(5) or (c)(6) of subpart G; or implements process changes that reduce emissions as specified in Sec. 63.138(c)(7) of subpart G. Control requirements include (1) suppressing emissions from the point of generation to the treatment device; (2) recycling the wastewater stream or treating the wastewater stream to the required Fr values for each HAP as listed in table 9 of subpart G; (3) recycling any residuals or treating any residuals to destroy the total combined HAP mass flow rate by 99 percent or more; and (4) controlling the air emissions generated by treatment processes. While emission controls are not required for Group 2 wastewater streams, owners or operators may opt to include them in management and treatment options. Suppression of emissions from the point of generation to the treatment device will be achieved by using covers and enclosures and closed vent systems to collect organic HAP vapors from the wastewater and convey them to treatment devices. Air emissions routed through closed-vent systems from covers, enclosures, and treatment processes must be reduced by 95 percent for combustion or recovery devices; or to a level of 20 ppmv for combustion devices. The treatment requirements are designed to reduce the HAP content in the wastewater prior to placement in units without air emissions controls, and thus reduce the HAP emissions to the atmosphere. The required Fr values in table 9 of subpart G are based on steam stripping. The final rule provides several compliance options, including percent reduction, effluent concentration limitations, and mass removal. For demonstrating compliance with the various requirements, owners or operators have a choice of using a specified design, conducting performance tests, or documenting engineering calculations. Appropriate compliance, monitoring, reporting, and recordkeeping provisions are included in the regulation. 6. Emissions Averaging Under subpart G, only owners or operators of existing sources may use emissions averaging. A change to the rule prohibits new sources from using emissions averaging to comply with the rule. Any process vents, storage vessels, or transfer racks in the source can be included in an emissions average. However, only wastewater streams that are not treated in a biological treatment unit are eligible for emissions averaging. Equipment leaks are regulated under a separate subpart and are also not eligible for emissions averaging. a. Credit/Debit System. In general, the system for accumulating and quantifying credits and debits remains the same as described at proposal. The owner or operator must identify all the emission points that would be included in an emissions average and estimate their allowable and actual emissions using the reference efficiencies of the reference control technologies for each kind of emission point. For each Group 1 point, the allowable emissions level is the emissions remaining after application of a reference control technology. As a result, all Group 1 emission points that are not being controlled with the reference control technology or a control measure achieving an equivalent reduction are emitting more than their allowable emissions. These points are generating emission ``debits.'' Emission debits are calculated by subtracting the amount of emissions allowed by the standard for a given emission point from the amount of actual emissions for that point. If a Group 1 emission point is controlled by a device or a pollution prevention measure that does not achieve the control level of the reference control technology, the amount of emission debits will be based on the difference between the actual control level being achieved and what the reference control would have achieved. Equations for calculating debits are provided in Sec. 63.150 of subpart G. The owner or operator must control other emission points to a level more stringent than what is required for that kind of point to generate emission ``credits.'' Emission credits are calculated by subtracting the amount of emissions that actually exist for a given emission point from the amount of emissions that would be allowed under subpart G, and then applying a 10-percent discount factor. If credits are generated through the use of a pollution prevention measure, no discount factor is applied. These provisions for a discount factor were added for the final rule. Equations for calculating credits are also provided in Sec. 63.150 of subpart G. To be in compliance, the owner or operator must be able to show that the source's emission credits were greater than or equal to its emission debits. Credits may come from: (1) Control of Group 1 emission points using technologies that the EPA has rated as being more effective than the appropriate reference control technology; (2) Control of Group 2 emission points; and (3) Pollution prevention projects that result in control levels more stringent than what the standard requires for the relevant point or points. A reference control technology cannot be used to generate credits beyond its assigned efficiency. For a new control technology or work practice, either the EPA or the permit authority must determine its control efficiency before it can be used to generate credits. b. Compliance. The rule requires that emissions averaging plans be reviewed as part of a source's Implementation Plan or operating permit application. The controls in the averaging plan would then be cited in a source's Implementation Plan or operating permit. Thus, to show compliance using emissions averaging, the owner or operator must prove both: (1) The appropriate controls have been applied and maintained; and (2) That the amount of emission credits and debits meet certain quarterly and annual requirements. c. Significant Changes. Significant changes were made to the emissions averaging provision. One change is that the number of emission points that can be included in an average has been limited to no more than 20 points or 25 points if pollution prevention is used. Another notable addition is the requirement that sources must demonstrate that their emissions average will not result in greater risk or hazard than compliance without averaging. Also, State or local agencies have been granted the discretion to not include emissions averaging in their implementation of the rule without having to go through the Sec. 112(l) rule delegation process. Summaries of significant comments and associated changes are discussed in section V.D of this preamble. All comments regarding emissions averaging are summarized and responded to in the BID, volume 2C. 7. Recordkeeping and Reporting The rule requires sources complying with subpart G to keep records and submit reports of information necessary to document compliance. Records must be kept for 5 years. For emission points where continuous monitoring is required, the final rule requires retention of hourly average data values rather than the 15-minute average values specified in the proposed rule. However, 15-minute values must be retained for operating days when the daily average value of the monitored parameter is outside the permitted range. The following five types of reports must be submitted to the Administrator: (1) Initial Notification, (2) Implementation Plan (if an operating permit application has not been submitted), (3) Notification of Compliance Status, (4) Periodic Reports, and (5) other reports. The requirements for each of the five types of reports are summarized below. a. Initial Notification. The Initial Notification is due 120 days after the date of promulgation for existing sources. For new sources that have an initial start-up more than 90 days after promulgation, the application for approval of construction or reconstruction required under the General Provisions must be submitted in lieu of the Initial Notification. The application is due as soon as practicable before commencement of construction or reconstruction, or 90 days after promulgation of subpart G, whichever is later. For new sources that have an initial start-up prior to 90 days after promulgation, no application for approval of construction is required and the Initial Notification is due within 90 days after promulgation. The Initial Notification must list the chemical manufacturing process units that are subject to subpart G, and which provisions may apply (e.g., process vents, transfer operations, storage vessels, and/ or wastewater provisions). A detailed identification of emission points is not necessary for the Initial Notification. However, the notification must include a statement of whether the source expects that it can achieve compliance by the specified compliance date. b. Implementation Plan. The Implementation Plan details how the source plans to comply with subpart G. An Implementation Plan is required only for sources that have not yet submitted an operating permit application. Existing sources must submit the Implementation Plan at different times for emission points included in averages and emission points not included in averages. The Implementation Plan for emission points included in an average is due 18 months prior to the date of compliance. The Implementation Plan for emission points not included in an emissions average is due 12 months prior to the date of compliance. For new sources that have an initial start-up more than 90 days after promulgation, the Implementation Plan must be submitted with the application for approval of construction or reconstruction. For new sources that have an initial start-up prior to 90 days after promulgation, the Implementation Plan is due within 90 days after promulgation (at the same time as the Initial Notification). This timing for new source submittals is slightly different than in the proposed rule. The information in the Implementation Plan should be incorporated into the source's operating permit application. The terms and conditions of the plan, as approved by the permitting authority, would then be incorporated into the operating permit. For points included in an emissions average, the Implementation Plan must include: An identification of all points in the planned average and whether they are Group 1 or Group 2 points; the specific control technique or pollution prevention measure that will be applied to each point; the control efficiency for each control used in the average; the projected credit or debit generated by each point; and the overall expected credits and debits. The Implementation Plan must also state that the same types of testing, monitoring, reporting, and recordkeeping that are required by the proposed rules for Group 1 points will be done for all points (both Group 1 and Group 2) included in an emissions average. For emission points not included in an average, the Implementation Plan must include a list of emission points subject to the process vents, storage vessels, transfer operations, and wastewater provisions and whether each point is Group 1 or Group 2. The control technology or method of compliance planned for each Group 1 point must be specified. The plan must also state that appropriate testing, monitoring, reporting, and recordkeeping will be done for each Group 1 point. If an owner or operator wishes to monitor a unique parameter or use a unique recordkeeping and reporting system for any emission point in their source, the request, including a rationale, must be submitted with the Implementation Plan, unless this information has already been included in their operating permit application. c. Notification of Compliance Status. The Notification of Compliance Status must be submitted within 150 days after the source's compliance date. It contains information on Group 1 points and all points in emissions averages that is necessary to demonstrate that compliance has been achieved, such as: The results of any performance tests for process vents, transfer operations, and wastewater emission points; one complete test report for each test method used for a particular kind of emission point; TRE determinations for process vents; design analyses for storage vessels and wastewater emission points; site-specific ranges for each monitored parameter for each emission point and the rationale for the range; and values of all parameters used to calculate emission credits and debits for emissions averaging. d. Periodic Reports. Generally, Periodic Reports must be submitted semiannually. However, there are two exceptions. Quarterly reports must be submitted for all points included in an emissions average. In addition, if monitoring results show that the parameter values for an emission point are outside the established range for more than the number of excused excursions, the implementing agency may request that the owner or operator submit quarterly reports for that emission point. After 1 year, semiannual reporting can be resumed, unless the implementing agency requests continuation of quarterly reports. All Periodic Reports must include information required to be reported under the recordkeeping and reporting provisions for each emission point. For emission points involved in emissions averages, the report must include the results of the calculations of credits and debits for each month and for the quarter. For continuously monitored parameters, the data on those daily periods when the parameters are outside their established ranges are included in the reports. Periodic Reports must also include results of any performance tests conducted during the reporting period and reports of equipment failures, leaks, or improper work practices that are discovered during required inspections. Additional information the source is required to report under its operating permit or Implementation Plan would also be described in Periodic Reports. e. Other Reports. Other reports must be submitted as required by the provisions for each kind of point. Other reports include: reports of start-up, shutdown, and malfunction; notifications of inspections for storage vessels; and information about sources requesting approval for a nominal control efficiency for use in calculating credits for an emissions average. C. Summary of Subpart H The applicability and provisions of subpart H generally have not changed since proposal. Minor changes have been made, however, to clarify the EPA's intent in some provisions and some revisions were made to recordkeeping and reporting provisions to reduce unproductive efforts. The following is a brief summary of the requirements of the provisions in subpart H of the final rule. 1. Applicability The standards would apply to equipment in organic HAP service 300 or more hours per year that is associated with a process subject to subpart F or I of part 63. The provisions apply to valves, pumps, connectors, compressors, pressure relief devices, open-ended valves or lines, sampling connection systems, instrumentation systems, surge control vessels, bottoms receivers, and agitators. The provisions of subpart H also apply to closed vent systems and control devices used to control emissions from any of the listed equipment. For SOCMI processes, compliance with the provisions of subpart H is phased in by type of chemical manufacturing process. Subpart F divides the regulated processes into five distinct groups to which the provisions of subpart H apply beginning 6 months after publication of the final rule in the Federal Register. Thereafter, subpart H applies to another group of processes every 3 months. Table 1 of subpart F lists the group to which each chemical manufacturing process subject to this rule is assigned. Processes listed in subpart I must comply with the provisions of subpart H 6 months after publication of the final standard in the Federal Register. a. Pumps and Valves. The standard requires leak detection and repair for pumps in light liquid service and for valves in gas or light liquid service. Standards for both are implemented in three phases. The first and second phases for both types of equipment consist of an LDAR program, with lower leak definitions in the second phase. The LDAR program involves a periodic check for organic vapor leaks with a portable instrument; if leaks are found, they must be repaired within a certain period of time. In the third phase, the periodic monitoring (a work practice standard) is combined with a performance requirement for an allowable percent leaking components. The standard requires monthly monitoring of pumps using an instrument and weekly visual inspections for indications of leaks. In the first two phases of the valve standard, quarterly monitoring is required. In phase three, semiannual or annual monitoring may be used by process units with less than 1 percent and less than 0.5 percent leaking valves, respectively. In phase three, if the base performance levels for a type of equipment are not achieved, owners or operators must, in the case of pumps, enter into a QIP, and in the case of valves may either enter into a QIP or implement monthly LDAR. The QIP is a concept that enables plants exceeding the base performance levels to eventually achieve the desired levels without incurring penalty or being in a noncompliance status. As long as the requirements of the QIP are met, the plant is in compliance. The basic QIP consists of information gathering, determining superior performing technologies, and replacing poorer performers with the superior technologies until the base performance levels are achieved. b. Connectors. The rule also requires leak detection and repair of connectors in gas or light liquid service. The monitoring frequency for connectors is determined by the percent leaking connectors in the process unit and the consistency of performance. Process units that have 0.5 percent or greater leaking connectors are required to monitor all connectors annually. Units that have less than 0.5 percent may monitor biannually and units that show less than 0.5 percent for two monitoring cycles may monitor once every 4 years. c. Other Equipment. Standards for compressors, open-ended lines, pressure relief devices, and sampling connection systems remain essentially unchanged from the proposed standard and other existing equipment regulations (See 40 CFR part 61, subpart V). The provisions for closed vent systems were revised to make them consistent with the provisions in subpart G, and to clarify intent. Agitators must be monitored for leaks or better designed systems, such as dual mechanical seals, must be installed. Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service are subject to instrument monitoring only if evidence of a potential leak is found through sight, sound, or smell. Instrumentation systems consist of smaller pipes and tubing that carry samples of process fluids to be analyzed to determine process operating conditions or systems for measurement of process conditions. 2. Delay of Repair Under certain conditions delay of repair beyond the required 15 days may be acceptable. Examples of these situations include where: (1) A piece of equipment cannot be repaired without a process unit shutdown, (2) equipment is taken out of organic HAP service, (3) emissions from repair will exceed emissions from delay of repair until the next shutdown, and (4) equipment with better leak performance such as pumps with SMS are replaced with DMS. 3. Alternative Standards Specific alternative standards have been written for batch processes and enclosed buildings. For batch processes, the owner or operator can choose either to meet similar standards to those for continuous processes, with monitoring frequency prorated to time in use of organic HAP, or to periodically pressure test the entire system. For enclosed buildings, the owner or operator may forego monitoring if the building is kept under a negative pressure and emissions are routed through a closed vent system to an approved control device. 4. Test Methods and Procedures The standards require the use of Method 21 of appendix A of part 60 to detect leaks. Method 21 requires a portable organic vapor analyzer to monitor for leaks from equipment in use. Test procedures using either a gas or a liquid for pressure testing the batch system are specified to detect for leaks. 5. Recordkeeping and Reporting The standards require certain records to demonstrate compliance with the standard and the records must be retained in a readily accessible recordkeeping system. Subpart H requires that records be maintained of equipment that would be subject to the standards, testing associated with batch processes, design specifications of closed vent systems and control devices, test results from performance tests, and information required by equipment in QIP. Other recordkeeping requirements are specified in Sec. 63.181 of subpart H. Subpart H requires owners and operators to submit three types of reports: (1) An Initial Notification; (2) a Notification of Compliance Status; and (3) Periodic Reports. Owners or operators subject to the requirements of subpart G as well as subpart H may submit one Initial Notification for both requirements. Owners or operators of sources subject to subparts I and H must submit an Initial Notification that lists the units subject to subpart H and the location of the source. The Notification of Compliance Status must be submitted within 90 days after the compliance date for process units in the first group. Thereafter, the owner or operator must submit a Periodic Report every 6 months that contains summary information on the leak detection and repair program, changes to the process unit, changes in monitoring frequency or monitoring alternatives, and/or initiation of a QIP. The Periodic Report will also include any Notification of Compliance Status for any process units that had compliance dates in the previous 6-month period. Reports can be submitted on electronic media that are compatible with the system used by the Administrator or the State permitting authority. D. Summary of Subpart I In contrast to the sources in the SOCMI source category, sources in the non-SOCMI processes would be covered by subparts I and H only. For these processes, the source would include only pumps, compressors, agitators, pressure relief devices, sampling connection systems, open- ended valves or lines, valves, connectors, and instrumentation systems. As explained in the Source Category Schedule for Standards (58 FR 63941), the EPA is considering regulating the other kinds of emission points in these processes in future section 112 standards. The processes subject to subpart H of the HON are included in 20 different source categories or subsets of source categories. The exact relationship of the HON's equipment leak processes to the source categories listed for section 112 standards is specified in table 1 of the Source Category Schedule for Standards (58 FR 63941). IV. Impacts This section presents the environmental, energy, cost, and economic impacts resulting from the control of HAP emissions under the rule. It is estimated that approximately 370 sources and 940 chemical manufacturing processes would be required to apply controls by the standards. Impacts are presented relative to a baseline set at the level of control in the absence of the rule. The estimates include the impacts of applying control to: (1) Existing emission points and (2) additional emission points from SOCMI process units that are expected to begin operation over a 5-year period. Thus, the estimates represent annual impacts occurring in the fifth year. Assuming a SOCMI-wide growth rate of 3.5 percent each year over a 5-year period, national impacts for the emission points that will be added in the first 5 years of the rule are estimated to be 19 percent of total national impacts in the fifth year. A. Environmental Impacts Environmental impacts include the reduction of HAP and VOC emissions, increases in other air pollutants, and decreases in water pollution and solid waste resulting from the proposed rule. Under the rule, it is estimated that emissions of HAP would be reduced by 460,000 Mg/yr (510,000 tons/yr) and the emissions of VOC's would be reduced by 950,000 Mg/yr (1,000,000 tons/yr) (see table 1). Estimates of baseline emissions are presented in conjunction with emissions reductions estimates to better illustrate the level of control being achieved by the rule. Baseline emissions take into account the current estimated level of emissions control, based on State and Federal regulations, for each SOCMI emission point. As a result, baseline emissions reflect the level of control that would be achieved in the absence of the rule. The baseline emission estimates in table 1 include the extrapolation of estimates for well-characterized processes to account for processes that could not be characterized. Consequently, the table 1 estimates contain considerable uncertainty and are presented only to provide an estimate of the total nationwide impact of the rule. Decisions were based on information from the well-characterized processes only. As discussed in section III.B.3 of this preamble, the EPA has deferred the final decision regarding control of medium-sized storage vessels at existing sources. Therefore, emission reductions for storage vessels shown in table 1, and consequently the total, may be slightly overstated. On average, SOCMI sources generate over twice as much VOC emissions as HAP emissions. Although the intent of the rule is to reduce HAP emissions, the control of HAP's also results in the control of non-HAP VOC's. The control requirements of the HON would result in reduction of 88 percent of HAP emissions and 79 percent of VOC emissions beyond the baseline control level. There would be a very slight increase in emissions of CO and NOX, relative to other sources of these pollutants, resulting from the on-site combustion of fossil fuels as part of control device operations. Additional emissions of NOX and CO (and other pollutants) resulting from increased electricity demand are not included in the impacts presented. Under the rule, estimates of increased emissions of CO and NOX are 1,700 Mg/yr (1,900 tons/yr) and 17,000 Mg/yr (19,000 tons/yr), respectively (see table 2). The impacts for process vents and transfer operations are based on the assumptions that incinerators or flares are used to combust emission streams. To the extent noncombustion controls are used to achieve compliance with the standards, the actual CO and NOX emissions would be lower. Impacts for water pollution and solid waste were judged to be negligible and were not quantified as part of the impacts analysis. The basis for judging these impacts to be negligible is discussed in chapter 5.0 of proposal BID volume 1A. B. Energy Impacts Increases in energy use were estimated for steam, natural gas, and electricity. These three types of energy were compared and totaled on a BOE basis. Table 3 shows the estimated individual and total energy use increases. Estimates for total energy use are 290 million kw-hr/yr of electricity, 6,900 billion Btu/yr of natural gas, and 3,000 billion Btu/yr of steam. This equates to 13,000 TJ/yr (2.1 million BOE/yr). C. Cost Impacts Cost impacts include the capital costs of new control equipment, the cost of energy (supplemental fuel, steam, and electricity) required to operate control equipment, and operation and maintenance costs. Generally, cost impacts also include cost savings generated by reducing the loss of valuable product in the form of emissions. Average cost effectiveness P($/Mg of pollutant removed) is also presented as part of cost impacts. Average cost effectiveness is determined by dividing the annual cost by the annual emission reduction. For the final rule, it is estimated that total capital costs for installation of controls would be $450 million (1989 dollars), and total annual costs of this control, excluding the cost savings attributable to equipment leaks, would be $160 million (1989 dollars) per year (see table 4). Because of the EPA's deferral of a final decision on control of medium-sized storage vessels at existing sources, as discussed in section III.B.3 of this preamble, the cost impacts for storage vessels, and consequently the total cost impacts, may be slightly overstated. The estimated cost of the monitoring, recordkeeping and reporting requirements for the rule is $70 million/ yr. The total nationwide annual cost of this rule is, therefore, $230 million/yr. It is expected that the actual compliance cost of the rule would be less than those presented, but it is not possible to quantify the amount. This is because cost estimates for some kinds of emission points were made assuming a separate control device would be constructed for each emission point. In reality, some operators will duct emissions from several of these emission points to a common control device, upgrade an existing control device, use other less expensive control technologies, implement pollution prevention technologies, or use emissions averaging. Additionally, owners or operators of sources may develop more efficient monitoring and recordkeeping systems. All of these options would reduce the estimated costs while achieving the same emission reductions. The effect of such practices on the national costs could not be estimated because the ability to use any of these practices is highly site-specific and data were not available to estimate how often the lower cost compliance practices could be utilized. D. Economic Impacts Because many SOCMI chemicals are used as raw materials in the production of other SOCMI chemicals, the economic impact analysis looked at cumulative costs of control for each of the SOCMI chemicals listed in subparts F and H. About 94 percent of the chemicals are estimated to have a production cost increase of less than 10 percent; more than 88 percent have cost increases less than 3 percent. Approximately 6 percent of the chemicals analyzed incur a cost increase of over 10 percent. Almost all of the chemicals with a product cost increase exceeding 10 percent have annual national production of less than 10 million kilograms (11,000 tons) and are therefore low volume chemicals. [Two-thirds of the SOCMI chemicals have production over 10 million kilograms (11,000 tons).] Market analyses for a subset of 21 of the chemicals estimated price increases from 0.1 percent to 3.9 percent and quantity decreases from 0.1 percent to 4 percent. The market analyses lead to the conclusion that percentage quantity decreases will be less than the percentage cost increases due to the regulation. The market analyses indicate that severe disruption of the industry is an unlikely result. The diversity of chemical producers (most sources are involved in the production of several chemicals) decreases the likelihood of plant closure as a result of the regulation. A more likely consequence of the regulation is a change from a chemical manufacturing process with a higher cumulative control cost to a process with a lower control cost. The impact for the low volume chemicals is the most uncertain. The cost estimates for these chemicals involve more uncertainty and, in many cases, industry profile information specific to the manufacturers of these chemicals was not available. Many of the low volume chemicals can be considered specialty chemicals. Generally, there is a lack of viable substitutes for specialty chemicals. In addition, the production cost of specialty chemicals is usually only a small portion of the cost of the final goods made with the specialty chemical. For these two reasons, a price increase for a specialty chemical is less likely to lead to a business closure or a production cutback than a price increase for a large volume chemical. This decreases the likelihood of large quantity impacts or closures. The RIA addresses the benefits, costs, and economic impact of the regulation. Because benefits could only be addressed qualitatively, the RIA is not able to provide guidance as to which regulatory option optimizes net benefits. However, the RIA does summarize the types of benefits associated with the reduction of HAP's, VOC's, and particulate matter formed from VOC's. V. Summary of Significant Comments and Associated Changes to the Proposed Subparts F and G A. Selection of Source Category and Source 1. Definition of SOCMI Public comments have indicated confusion regarding the definition of the source category covered by the HON. Several commenters misinterpreted the definition to include activities that were not intended to be regulated with this rule such as marine vessel loading and refinery processes. Thus, the commenters asserted that the proposed rule contained too many exemptions and loopholes. The commenters concluded that the EPA should broaden the scope of the HON. Section 112(c) of the Act requires the EPA to publish a list of all categories of major sources of listed HAP's (and such categories of area sources as the Administrator determines warrant regulation), then to establish rules for each of these categories of sources of HAP emissions. As such, the HON was not intended to require controls for all operations in the chemical industry. Rather, the HON sets section 112(d) standards for the SOCMI source category. The SOCMI source category includes only the part of the chemical industry that produces the major industrial chemicals. Other parts of the chemical industry use SOCMI chemicals to produce pesticides, agricultural chemicals, pharmaceuticals, polymers, and specialty chemicals. These operations are substantially different than the SOCMI and were outside the scope of the impact analysis for the HON. Accordingly, these other segments of the chemical industry are separate source categories, and will be subject to separate MACT or GACT standards at a later date. The EPA acknowledges that some integrated facilities will have operations from multiple source categories on the same plant site (e.g., refinery units, SOCMI production, and pesticide production). However, to include all emission points at these facilities in the scope of the HON is inappropriate because it is not consistent with Congressional intent to regulate categories of HAP emissions. Further, such an undertaking would make implementation of the rule an insurmountable task. Instead, the HON provides comprehensive coverage of the emissions of 112 organic HAP's from five kinds of emission points in 385 SOCMI production processes. Emissions from processes in other source categories will be covered by separate MACT standards. In conclusion, the EPA does not believe it would be practical or appropriate to broaden the applicability of the HON, as suggested by some commenters, to include emissions from other source categories. In previous rules and in the proposed HON, the EPA defined the SOCMI source category with lists of chemical products. In the proposed HON, there were two lists of SOCMI chemicals. One listed chemicals that would be subject to subpart G and the other listed chemicals that would be subject to subpart H. The two differed because the subpart H list had been agreed to by the negotiating committee before all technical analyses were complete. Commenters suggested simplifying the applicability of the HON by making the lists identical or by combining them into a single list. Other commenters asserted that there were non-SOCMI chemicals (e.g., phthalate esters) on the proposed lists and that these chemicals should be removed from the final rule. The EPA agrees with the commenters that the applicability of the rule will be clearer if there is only one list of SOCMI chemicals. Thus, the EPA has combined the two lists and placed the resulting list in table 1 of subpart F of part 63. The EPA re-evaluated several chemicals that some commenters had claimed were not SOCMI chemicals. In several cases the EPA disagreed with the commenters because the chemicals met the criteria that EPA has used to define the SOCMI. However, the EPA agreed with the commenters regarding phthalate esters. These chemicals are primarily used as plasticizers, not as building blocks for other chemical manufacturing, and will be regulated under a separate source category called ``Phthalate Plasticizer Production.'' Because the production of these chemicals will be covered by a future section 112(d) standard, the EPA felt that it would be inappropriate to include them under the HON. Thus, phthalate esters were deleted from the list of SOCMI chemicals in the final rule. The EPA added a chemical to the HON SOCMI list that had previously been listed as a separate source category. The dodecanedioic acid process shares equipment with an adiponitrile process which is subject to the provisions of the HON. The EPA determined that it would be more appropriate to regulate production of dodecanedioic acid as part of the HON rather than prepare a separate standard. Thus, this chemical has been added to the list of SOCMI chemicals in the HON. Several commenters have alleged that the applicability provisions in the proposed HON are confusing, especially when applied to plant sites with integrated operations. To address the confusion, the EPA has clarified the provisions in the final rule to simplify the determination of applicability for facilities with integrated operations. Several commenters suggested that the term ``chemical manufacturing process'' be clarified regarding where the coverage of the HON begins and ends. The commenters described situations where: (1) Unit operations produce a SOCMI chemical as part of an overall non-SOCMI process; (2) Solvent is recovered or reclaimed; (3) Unit operations, storage vessels, and transfer racks are shared by two or more processes; and (4) The intended product is less than a by-product on a mass basis. In the final rule, the EPA has changed the term ``chemical manufacturing process'' to ``chemical manufacturing process unit'' and provided additional clarification on the boundary of a process subject to the HON. The term is now defined as follows: Chemical manufacturing process unit means the equipment assembled and connected by pipes or ducts to process raw materials and to manufacture an intended product. For the purpose of this subpart, chemical manufacturing process unit includes air oxidation reactors and their associated product separators and recovery devices; reactors and their associated product separators and recovery devices; distillation units and their associated distillate receivers and recovery devices; associated unit operations; and any feed, intermediate and product storage vessels, product transfer racks, and connected ducts and piping. A chemical manufacturing process unit includes pumps, compressors, agitators, pressure relief devices, sampling connection systems, open-ended valves or lines, valves, connectors, instrumentation systems, and control devices or systems. A chemical manufacturing process unit is identified by its primary product. Additionally, the final rule provides a comprehensive assignment procedure for distillation units, storage vessels, and transfer racks that are shared among processes. This assignment procedure is based on the predominant use of the equipment. The EPA has also clarified the term ``source'' by consolidating the definition into two adjacent paragraphs and wording it more in terms of equipment having specific functions. These and other clarifications should remove the confusion on the limits of a chemical manufacturing process unit subject to the HON. Commenters also asserted that the proposed definition of ``flexible operation unit'' was inadequate because it addressed only feedstock changes, and not operating changes to accommodate different products or specifications. Because changes in these units could be frequent, the commenters suggested basing applicability on the previous year's production. In the final rule, the EPA has changed the definition of ``flexible operation unit'' to include operating changes. Additionally, the EPA reevaluated the proposed requirement that a flexible operation unit would be subject to the HON only during times when the unit was producing a SOCMI product. The EPA decided that, due to the frequent product changes associated with flexible operation units, such a provision could complicate compliance determinations for sources and enforcement agencies. The EPA considered the commenters' suggestion to base applicability on the previous year's production but decided against this because the year preceding promulgation of the final rule might not have been representative of typical operation of the unit. Therefore, in the final rule flexible operation units are assigned to a specific chemical manufacturing process unit based on the anticipated use of the unit. For existing sources, assignment is based on the expected use over the first five years following promulgation, and for new sources, assignment is based on expected use in the first five years after start-up. 2. Definition of Major Source The EPA received a number of comments regarding a source's potential to emit. The EPA's policy on potential to emit is enunciated in the General Provisions. The reader is directed to those provisions for guidance. Public comments have indicated confusion on the applicability of the HON to a SOCMI chemical manufacturing process unit at a plant site where the predominant activity is part of another source category (e.g., a petroleum refinery). Some commenters pointed out that the permit rule (40 CFR 70.2) narrowed the basis for determination of major source status to include only the emission points within a single two- digit SIC code. The commenters argued that this change would mean that the HON would apply only if a source was major due to its SOCMI processes. In other words, if the SOCMI processes at a source did not exceed the 10/25 tons per year HAP emission threshold, then the HON would not apply. The EPA maintains that, although 40 CFR 70.2 defines major source for the purpose of permitting, it does not alter the statutory definition under section 112. The permit rule applies to sources subject to a section 112(d) standard regardless of whether they are major sources as defined by 40 CFR 70.2. The EPA's position remains that if a plant site is a major source within the section 112 definition, the HON applies to the HAP-emitting SOCMI processes, and that the applicability of the HON to the SOCMI portion of the plant site is not limited by the principal activity at the site. This is consistent with the intent of the Act to regulate categories of HAP emission sources. The part 70 definition may result in more than one permit being issued for a major source of HAP emissions, but does not affect the applicability of MACT standards. 3. Exclusion of Area Sources In the preamble to the proposed HON, the EPA requested information on the existence and characteristics of any area sources in the SOCMI in order to determine if a separate MACT standard should be prepared. Because the comments did not indicate any reasons to develop an area source standard, the EPA maintains that the HON applies to major sources only. Area sources are not subject to the HON. 4. Determining New Source Status The EPA received a number of comments regarding the process for determining if new or existing source requirements would apply to a particular SOCMI emission point or process unit. In response to those comments the EPA has clarified the relevant section of subpart F. The requirements and definitions used by the HON to distinguish new and existing sources are consistent with section 112(a) and the related components of the General Provisions. As a result, the following could be subject to the HON's requirements for new sources: (1) Chemical manufacturing process units constructed after the date of proposal of the HON (December 31, 1992); (2) existing sources reconstructed after that date; and (3) ``greenfield'' HON chemical manufacturing process units that constitute all or part of a major source constructed after that date. (New source requirements would not be triggered by the addition of an individual emission point, such as a storage vessel.) In addition, a newly constructed chemical manufacturing process unit must also have the potential to emit major quantities (10 tons per year of any HAP or 25 tons per year of any combination of HAP's) in order to be subject to new source requirements for the HON. Thus, any change or addition to an existing SOCMI plant site must meet the same three criteria as a ``greenfield'' plant to be considered a new source. The EPA selected this approach for determining what is subject to new source requirements to avoid providing an incentive for SOCMI owners and operators to construct processes as area sources. Also, EPA wanted to ensure that new sources built at existing plant sites are subject to the same requirements as new sources that are ``greenfield'' sites. Additions to an existing plant that do not meet the requirements of being a chemical manufacturing process unit and do not have the potential to emit major amounts, will be subject to existing source requirements. B. Selection of Pollutants In selecting the HAP's that would be regulated by the HON, the EPA started with the list of 189 HAP's in the Act. Because the HON was intended to reduce emissions from organic chemical manufacturing, the EPA studied the processes used to manufacture SOCMI chemicals and narrowed the list to those organic HAP's that would be emitted from SOCMI processes. In the proposed rule, there were two lists of organic HAP's--one that applied to subpart G and another that applied to subpart H. The lists differed by 37 HAP's because the subpart H list had been agreed to by the negotiating committee before all technical analyses were complete. These technical analyses indicated that 37 of the organic HAP's on the list approved by the committee should be removed from the list because they would not be emitted from SOCMI production processes. In public comments received on the proposed rule, it was suggested that the EPA combine the two lists to simplify implementation of the rule. The EPA decided that it was appropriate to include only one list of organic HAP's in the final rule. The list is located in table 2 of subpart F and contains 112 compounds. Keeping the shorter of the two proposed lists will not result in greater emissions because the additional 37 HAP's on the longer list would not be emitted from SOCMI processes. Also, because the non-SOCMI processes in subpart I are only subject to the standard for the designated pollutants, combining the organic HAP lists does not affect emissions from those processes. C. Selection of Rule 1. Floor Determination a. Background on impacts estimates. As explained in the preamble to the proposed rule (57 FR 62621), the EPA developed the information on control costs and emissions for SOCMI using a model emission point approach to represent the broad range of characteristics of SOCMI operations. The EPA elected to use the model emission point approach in part because of the limited time provided by the statutory requirement to regulate 40 source categories (which legislative history states should be the priority elements of the chemical industry) by 1992 and to establish regulations for all initially listed source categories by 2000. Because a generic model emission point approach allows one regulation to cover a large number of different chemical processes, it was considered more resource efficient and the only practical way to develop regulations on the schedule mandated by Congress. The impacts estimation methodology involved three steps: (1) Development of a data base characterizing the SOCMI, (2) development and assignment of model emission points for each kind of emission point, and (3) calculation of emissions and control impacts. The characterization of the SOCMI primarily involved identifying the specific routes, reactants, and process technologies used to produce a chemical and the corresponding SOCMI chemical manufacturing process units. In addition, information on existing State and Federal regulations was compiled for each kind of emission point to determine the baseline control requirements applicable to SOCMI chemical manufacturing process units. Model emission points were developed to represent each kind of emission point in the SOCMI. The models were developed to emphasize those characteristics that most influence emissions, control costs, energy needs, and secondary environmental impacts. These models were applied to individual chemical manufacturing process units in the SOCMI data base using decision rules based on the level of information in the data base and the specificity of a given model. These models are representative of average, representative, or typical emissions for the specific process or reaction type. Thus, the estimates do not reflect actual emissions that would occur at any particular chemical manufacturing process unit because process design and operation characteristics vary from plant to plant. Estimates of existing controls were developed by compiling information in existing state and Federal regulations applicable to SOCMI processes. In this analysis, the EPA used data on the control requirements in existing State and Federal regulations to identify those emission points that must be controlled in the absence of this rule and to identify the required controls. It was assumed that all chemical manufacturing process units would be in compliance with applicable air pollution regulations. The data base and model emission points used to estimate the impacts of the HON are based on published literature and information that the EPA has collected during other rulemaking efforts including NSPS for air oxidation processes, distillation operations, reactor processes, volatile organic liquid storage, and equipment leaks; and NESHAP for vinyl chloride and benzene. Some additional information was obtained on wastewater operations and transfer loading operations by requesting it from the industry under authority of section 114 of the Act. In development of the proposed rule, the EPA recognized that the data base developed to provide estimates of nationwide costs and emission reductions did not provide site-specific emission and control information and these limitations needed to be considered in the determination of the floor for the category. The EPA developed the floor from an analysis of the information for each kind of emission point. The information the EPA used in determining the source-wide floor consisted of the estimates of the number and characteristics of the model emission points, the emission control requirements currently in place for each point based on information available to the EPA, and the expected control efficiencies for the control technology. To determine the source-wide floor for existing sources at proposal, the EPA examined the supporting information to identify the emission characteristics of the emission points which had at least 12 percent of the points controlled by the reference control technology. This analysis was done for each kind of emission point. The characteristics used to identify groups of emission points were physical parameters such as flow rate, HAP concentration, and vapor pressure. The source- wide floor was determined by the combination of the control levels for all four kinds of emission points. A similar method was used to determine the source-wide floor for new sources. For each kind of emission point, the characteristics of the smallest emission point controlled by the reference control technology were identified as the means for determining the best controlled similar source. Again, the source-wide floor was determined by the combination of control levels for all emission points. b. Public comment issues. Commenters raised three basic issues on the approach used to determine the floor for SOCMI sources: (1) Information used to predict existing control understated actual control present; (2) The methodology used to estimate the floor overstated the floor; and (3) The ranking criterion used for process vents introduced cost considerations into the floor. Data base understates actual control. A number of commenters argued that the approach, or the information, the EPA used understated actual control in the SOCMI. Some of these commenters thought that the EPA should have gathered site-specific data on emissions and controls to properly establish the floors. Other commenters argued that the EPA should have used state air toxics and new source review permits to determine actual control levels, since many air toxics programs are implemented through permit programs. While the EPA would have preferred to have developed site-specific information on emissions and controls for processes subject to this rule, it was not possible to do so given the deadlines applicable to this rulemaking. Section 112(e)(1) of the CAA required that the EPA promulgate emission standards for at least 40 source categories and subcategories by November 15, 1992. Having failed to meet that statutory deadline, the EPA entered into a consent decree requiring the promulgation of the HON by February 28, 1994. Neither that deadline nor the statutory deadline for the rules covering 40 source categories and subcategories could have been met if the EPA used the alternative approach suggested by the commenters. The EPA's past experience in developing the data base for the previous section 112 program and for NSPS standards demonstrates the great length of time necessary to develop and analyze the data for development of emission standards to control emissions from the SOCMI. The data base developed for this rulemaking used the results of more than 10 years of data gathering and analysis of SOCMI sources. Developing an entirely new data base as suggested by the commenters is expected to require anywhere from 4 to 10 years depending on the degree of evaluation of performance and whether permits are reviewed for all SOCMI sources. Consequently, the EPA elected to use information readily available to it to determine the floor for the SOCMI standard under section 112(d) of the CAA. In light of the EPA's prior experience with regulation of the SOCMI, the EPA believes that this decision was entirely reasonable. Furthermore, the EPA does not believe that the method used by the EPA to determine existing control levels and the floor understated actual control levels in SOCMI. The EPA holds this view because other assumptions used in the analysis introduced a positive bias. Examples of assumptions that would introduce an upward bias to the analysis include: (1) All sources are in compliance with all applicable control requirements for air emissions; and (2) sources would be in compliance with recently established requirements such as 40 CFR part 61 subpart BB. Thus, the EPA believes that taken as a whole the uncertainties should balance out, and the control level is not understated. It should be noted also that other commenters thought that the floor was overstated. Methodology overstated floor. In contrast, another group of commenters argued that the point-by-point approximation of the floor introduced a positive bias in the source-wide floor. These commenters explained that the assumption that the best controlled of each kind of point are co-located is invalid. They noted that in practice different sources have the better controls on the different kinds of points. These commenters argued that the EPA should have considered this bias in decisions to require control beyond the floor. Some of these commenters also questioned inclusion of requirements in recent NESHAP in the assessment of the floor control and the estimates of control efficiency achieved by some control devices. None of the commenters provided data or suggested methodologies that could be used to improve the EPA data base to develop better estimates of the source-wide floor. The EPA maintains that, given the uncertainties in the data base, the procedure used to determine the floors in the proposal (and in this final rule) is a reasonable approach to the determination of the floor. As explained above, the EPA could not develop actual site-specific data in the time available for this rulemaking. Thus, the EPA had to rely on existing data sources to develop model emission points characteristics for sources subject to this rule. Where data were available for the specific process, the model emission points characteristics reflected average or representative operations for the specific process. In cases where no data were available for a specific process, the model emission point characteristics were derived from average characteristics for the generic reaction type (e.g., hydrogenation, halogenation, etc.). Thus, the estimates cannot be viewed as reflecting actual emissions and controls at any particular process unit or plant site. The EPA considered whether to develop floors using estimates of site-specific emissions and controls and rejected that approach as introducing additional assumptions and such large uncertainties as to render the analysis meaningless. For example, due to incomplete information, it is probable that not all process units at each plant site were properly identified. In fact, locations of some chemical production processes are unknown. Site specific differences in process unit design could not be taken into account in assigning model emission points and baseline control levels. Thus, there is uncertainty about the existence of any particular emission point, as well as its assigned emission and control level at any particular plant site. Furthermore, independent assignment procedures were used for each kind of emission point. In consideration of these factors, the EPA believes that the uncertainties introduced by the assumptions made in assigning emission point characteristics to specific sites are so large as to undermine the validity of the analysis. The EPA believes that the approach it used of developing point-by-point approximations of the source-wide floor was the most appropriate use of the available data base to determine the floors. Moreover, the EPA does not believe that its methodology, when all aspects are considered, did overstate the source-wide floor. While the assumption of collocation of the best controlled points does introduce an upward bias in the analysis, there are other aspects of the analysis that work in the opposite direction. For example, the use of information from State regulations instead of site-specific control and operation information would be likely to understate the degree of control present in some sources. As previous commenters noted, site- specific controls that may have been included in new source permits or applied voluntarily could not be accounted for in the data base. Thus, the EPA expects these factors are likely to balance out. It should be noted also that other commenters thought that the floor was understated. The EPA also believes that its choice of methodology was reasonable since it provided additional assurance that, not withstanding the uncertainties inherent in the data base, the floor determined by the EPA would be no less stringent than the actual source-wide floor. As some of the uncertainties present, such as the reliance on analyses of State regulations rather than actual permitted levels of emissions, would lead to a less stringent floor in the absence of countervailing factors, the EPA believes it was reasonable to provide a safety factor by determining the floor on the basis of a point-by-point approximation that assumed the co-location of the best-controlled points. In any event, even if the EPA's point-by-point methodology may have overstated the floor, such an overstatement does not invalidate the emission standard since the overall source-wide standard exceeds the floor determined by the EPA. A second issue raised regarding the methodology and information was whether it was appropriate to consider the Benzene Transfer (40 CFR part 61, subpart BB) or Benzene Waste (40 CFR part 61, subpart FF) NESHAP as applicable control requirements. These commenters questioned whether section 112(d)(3)(A) of the Act required that these control requirements not be considered in the floor determination. (See section II.C of this notice.) The EPA maintains that it was appropriate to consider the control requirements of Benzene Transfer since these controls were required more than 30 months before promulgation of this rule. Furthermore, information collected in the section 114 surveys shows that a few sources were steam stripping wastewater containing chemicals with volatilities similar to benzene. Because the new source floor is determined based on the best controlled similar source, the requirements were included in the determination of the floor for new sources. In addition, the Vinyl Chloride NESHAP, which was issued in 1977, also requires treatment of wastewater streams containing greater than 10 ppm. Consideration of the Benzene Waste NESHAP did not affect the existing source floor because fewer than 1 percent of the wastewater streams in the HON data base are expected to be subject to Benzene Waste NESHAP control requirements, and the floor is determined to be no control for wastewater streams at existing sources. Ranking criterion used for process vents analysis. Some commenters thought that the EPA had introduced cost considerations into the floor by the ranking procedure used for process vents. These commenters noted that considering cost in determining the floor was contrary to Congressional intent. The EPA does not believe that the procedure used to rank process vents did introduce cost into the determination of characteristics of process vents controlled at the floor. The reasons EPA holds this view can be best explained by restating the process used and comparing it to other ways of analyzing the process vent data. To determine the source-wide floor, the EPA ranked the data base for the specific emission point by a characteristic that would affect the likelihood for control. For existing sources, the proposed floor was defined as the emission characteristics where at least 12 percent of the points were controlled by the reference control technology. For new sources, the proposed floor was defined by the characteristics of the point with the smallest emission rate that was controlled. By analyzing the ranked data, it could be determined that emission points with certain physical characteristics are currently controlled, while emission points with other characteristics are not controlled. Storage vessels, for example, were ranked by vapor pressure because vapor pressure is one of the three major factors that influence emissions and potential emission reductions. The ranking clearly showed that vessels storing liquids above a certain vapor pressure are controlled at the best controlled sources, so the source-wide floor would require control of such vessels; whereas, vessels storing liquids with lower vapor pressures are not currently controlled and would not require control under the source-wide floor. Process vents were ranked using cost effectiveness of control (or TRE) as a surrogate measure because this can be used to reflect all possible combinations of various factors that affect emission rates and likelihood of current control (flow rate, HAP concentration, net heating value, and corrosion properties). Use of a single criterion of cost effectiveness results in a more easily understood parameter and is consistent with the format of the process vent provisions. The cost- effectiveness values were used only to rank the vents in the data base and as a characteristic to identify controlled vent characteristics (similar to the way in which vapor pressure was used to identify the characteristics of the best controlled storage vessels). In determining the process vent component of the source-wide floor, no judgements were made about the reasonableness of the characteristics of the controlled vents. Because of the opinions expressed by commenters, the EPA also reevaluated the process vent control level associated with the floor using emissions as the ranking parameter. Emissions correlate with likelihood of control, but the correlation is weaker because other factors (such as concentration and flow) also influence it. The process vent data base was ranked by vent from lowest to highest emission rate. The characteristics of the process vent where at least 12 percent of the process vents are controlled is 64 Mg/yr (71 tons/yr) and the cost- effectiveness value is $1,620/Mg ($1,460/ton). Thus, essentially identical results are obtained by both ranking procedures. As discussed in section V.C.1.c of this preamble, comment has been requested in other rulemakings on the meaning of the statutory language ``the average emission limitation achieved by the best performing 12 percent of the existing sources.'' Because of this, the average characteristics of the top 12 percent of the process vents were determined using the emissions ranking of the data base. This analysis showed that vents with 27 Mg/yr (30 tons/yr) emissions would have to be controlled at the floor. When these average characteristics are used to derive the comparable TRE value, the result is about $2,900/Mg ($2,600/ ton). The discussion of the control levels selected for existing process vents demonstrates that in this case the interpretation of the statutory floor language is not relevant. This is the case because, when cost and environmental and energy impacts are considered, as required by the statute, the appropriate control level for process vents is equal to the more stringent floor calculation. Thus any ambiguity in the floor language and methodology does not affect the regulatory alternative selected for this rule. Analysis of expected control efficiency at floor for storage vessels at existing sources. Several commenters questioned the assessment of the performance capabilities of actual controls on existing storage vessels. As discussed in section V.C.3 of this preamble, the performance was reassessed considering the comments. This reevaluation determined that for existing storage vessels best control systems are: (1) A 90-percent efficient control device; or (2) An IFR or EFR with a continuous seal, but without controlled fittings. Also in the reexamination of existing control level, it was determined that an error had been made in assignment of applicability of the Benzene Storage NESHAP (40 CFR part 60, subpart Y) to storage vessels in the data base. Upon examination of the data base, it was found that some vessels had been assumed to be controlled due to subpart Y, but the liquids stored did not meet the applicability criteria of subpart Y. The Benzene Storage NESHAP applies only to vessels storing liquids that meet the specifications of ASTM D-836-84 for industrial grade benzene, or refined benzene -485, -535, or -545. After correction of the data base, 2 percent of the small vessels, 6 percent of the medium vessels, and 12 percent of the large vessels were found to be controlled. The effect of this on the assessment of the floor for existing sources is discussed in the next section of this preamble. c. Interpretation of statutory language for existing source floors. In recent Federal Register notices of proposed rulemakings (Pulp and Paper and Chromium Electroplating), the EPA has requested comment on the EPA's interpretation of the meaning of ``the average emission limitation achieved by the best performing 12 percent of the existing sources'' and the methodology for determining the MACT floor. Comments have been specifically requested in these proposed rulemakings on whether the MACT floor for existing sources should be set at the 88th percentile or at the level reflecting the median or mean level of control achieved by the best performing 12 percent of sources. Questions have been raised on how the methodology used in determination of the floors for the HON relates to floors being determined using alternative procedures. With the exception of process vents and medium-sized storage vessels, the two methodologies result in the same control level for the floor. This results because for most of the HON data base there is little variation in the physical characteristics of the emission points in the top 12 percent of the population. The average or mean is equal to the median value of the distribution as well as the 88th percentile value. Thus, for this data base, whether the floor is determined using the characteristics of the median, mean or 88th percentile does not matter. The assessment of the average characteristics of the best performing 12 percent of each kind of point is described below. As described earlier in the discussion of the process vent ranking criterion, the average characteristics of the top 12 percent of the process vents was equivalent to about $3,000/Mg ($2,700/ton). The characteristics of process vents where at least 12 percent are controlled by the reference control technology is equivalent to $1,500/ Mg ($1,360/ton). For small storage vessels, the revised data base showed that only 2 percent of the vessels were controlled. Thus, the median characteristics of the top 12 percent of the vessels is no control. This control level is the same as the level predicted by characteristics where at least 12 percent are controlled. As mentioned earlier, the EPA is not taking final action at this time concerning the provisions applicable to medium storage vessels. The reason is to take comments on the difference in the floor determination that would result from the application of the two interpretations discussed above. For medium storage vessels, 6 percent of the vessels are controlled with either a 90-percent efficient control device or an IFR or EFR with a continuous seal. All of the controlled medium-sized vessels contained liquids with vapor pressures of 13.1 kPa (1.9 psia). The arithmetic average, or mean characteristics of the top 12 percent of the medium vessels would not represent the performance of any known technology. If the EPA used the median as the average for these vessels, however, the floor determined by the average characteristics of the top 12 percent of the sources would require control of vessels storing liquids with vapor pressures of 13.1 kPa (1.9 psia) by either a 90-percent efficient control device or an IFR or EFR with a continuous seal. This is the same vapor pressure that was identified at proposal. With the revised data base, the floor determined by the characteristics where at least 12 percent of the points are controlled would require no control. For large storage vessels, the revised data base showed that 12 percent of the vessels were controlled and essentially all controlled vessels in the top 12 percentile of each size range of vessels stored liquids with vapor pressures of 13.1 kPa (1.9 psia). So the median or average characteristics of the top 12 percent of the vessels is the same as the characteristics where at least 12 percent of the vessels were controlled. Both procedures show the floor to require control of vessels containing liquids with vapor pressures of 13.1 kPa (1.9 psia) and higher. The data base information for transfer racks also showed that all controlled racks loaded liquids with vapor pressures of 10.3 kPa (1.5 psia) and no racks loading liquids with vapor pressures less than 10.3 kPa (1.5 psia) were controlled. Thus, the two procedures would predict the same control requirements for the floor. Fewer than 1 percent of the wastewater streams in the HON data base were expected to be subject to regulations that required control of air emissions. Thus, for wastewater the average of the top 12 percent of streams would represent no control since the median stream is not controlled and the arithmetic average of the top 12 percent of the sources does not correspond to any known control measure. The alternative procedure for determining the floor also shows that the floor would be no control. In summary, the outcome of the debate concerning the appropriate interpretation of the floor language is not pertinent to the final provisions for process vents, transfer operations, wastewater, small storage vessels, and large storage vessels. Under either interpretation, the floor would not alter the regulatory decisions contained in this rule for those emission points because the standard is, on the basis of cost and environmental and economic impacts, set at or above each component of the floor regardless of which interpretation is chosen. In the case of medium storage vessels, however, the EPA is deferring final action pending the receipt and review of additional public comment. 2. Alternative Control Levels a. Stringency of standard. The proposed standard would have required control of emission points with characteristics meeting the criteria listed in table 5 through the use of reference control technologies. The EPA selected the proposed control requirements from the alternatives listed in tables 5 and 6 of the proposed notice of rulemaking (57 FR 62629 and 62630). These alternatives differed only in the number of emission points that would be controlled by the reference control technology. The proposed requirements were selected considering: (1) Magnitude of the emission reduction; (2) cost of the emission reduction; (3) economic impacts and feasibility; (4) consistency with previous decisions; (5) other non-air quality health and environmental impacts; and (6) energy requirements. It was the EPA's judgement that the proposed requirements would be achievable at reasonable cost, and with reasonable economic and other impacts. The proposed control requirements were expected to significantly reduce HAP emissions from SOCMI sources. The proposed standard was estimated to reduce HAP emissions from the four kinds of emission points by 422,000 Mg/yr (464,000 tons/yr) from existing and new sources. At proposal the total nationwide annual cost associated with this emission reduction was estimated to be about $182 million/yr, with $48 million/yr of this cost associated with the monitoring, recordkeeping, and reporting requirements. Public comments on the proposed control levels were polarized with industry groups arguing the proposed standard was too stringent and environmental and public interest groups arguing the standard did not require sufficient control. Commenters who argued that the standard was too stringent thought that in the decisions to go beyond the floor the EPA should have considered the bias introduced by the procedure used to determine the floor. Several commenters suggested alternative criteria which they considered to be more appropriate. These commenters, however, did not provide supporting rationale for their preferences. Commenters representing environmental and public interest groups expressed concern that the proposed standard did not require control of all emissions, but allowed a large amount of emissions to go uncontrolled. Several State and local regulatory agency commenters thought that, at a minimum, the standard should have required control comparable to existing control requirements for VOC, such as the NSPS standards for SOCMI process vents (40 CFR part 60, subparts III, NNN, and RRR). The EPA considered all of the comments in selecting the final control requirements of the standard. In considering these comments, the EPA viewed the concerns in the context that the positions and concerns were diametrically opposed to one another. Thus, no response could completely resolve the issues. The EPA's reexamination of the control requirements of the standard and response to the commenters' concerns is provided in the following paragraphs of this section of the preamble. The final regulatory alternatives for existing and new sources are shown in tables 6 and 7. [Note: Regulatory alternatives were developed using information for the chemical processes that could be characterized sufficiently to permit assignment of model emission points. The estimates presented in tables 6 and 7 differ from the estimates summarized in section IV of this notice because the estimates in section IV include an extrapolation to account for processes that could not be modeled.] The only differences between these alternatives and the alternatives at proposal are revisions made to the estimates of wastewater emissions and control costs and the storage vessel control costs, as discussed in sections V.C.3.b and V.C.3.d of this preamble. The following discussion of the final selection of control levels is limited to the primary factors that affected the decision. The primary factors are the emission reduction, control cost, consistency with other standards, and economic efficiency. Other factors such as non-air environmental impacts (solid waste and water) and energy impacts do not vary significantly among the alternatives. Consequently, these factors are not discussed in this preamble. Readers should see the proposed rulemaking (57 FR 62608) for the discussion of these other factors. (i) Process vents. In the final rule, the EPA selected Option 3 (TRE cost-effectiveness values of up to $3,000/Mg) as the basis for the requirements for process vents at existing sources. The EPA's selection of Option 3 for process vents was principally based on consideration of the emission reductions, costs, and consistency with other standards. Specifically, the control level required by this option will reduce emissions by 2,000 Mg/yr (2,200 tons/yr) more than Option 2, upon which the proposed requirements were based. This additional emission reduction is estimated to cost approximately $4 million/yr more than Option 2 or $2,500 for each additional Mg of emissions ($2,270/ton). The EPA believes that the control required by Option 3 is achievable considering the statutory criteria, for the following reasons. First, EPA has received extensive comment on the proposed rule. No commenters submitted data or arguments demonstrating that the costs of the proposed range of options (Options 1 to 4) were unreasonable. Second, the incremental cost effectiveness of Option 3 compared to Option 2 ($2,500/Mg [$2,275/ton]) is within the cost- effectiveness values from recent decisions on other standards. Third, the TRE format of the process vents provisions allows facilities the flexibility to comply through changes in equipment or operations. As a result, actual costs could be lower than estimated. Based on the above considerations, the EPA judged that the control required by Option 3 is achievable considering the statutory criteria. Fourth, Option 3 would provide consistency between the HON and the recently issued CTG for SOCMI process vents, which requires control of vents with TRE cost-effectiveness values of $2,500/Mg of VOC ($2,270/ ton). Option 3 would also be consistent with the applicability criteria for the three SOCMI process vents NSPS, which require control of vents with TRE cost-effectiveness values of $3,000/Mg of VOC ($2,700/ton) adjusted to 1989 dollars. The EPA believes that consistency among these requirements would reduce administrative costs and implementation difficulties for both EPA and permit authorities as well as industry. An additional consideration in selection of Option 3 was public comments that the requirements should be at least equivalent to the requirements of the SOCMI NSPS and CTG. In addition, Option 3 is consistent with one interpretation of the statutory language on floors, and thereby arguably is the minimum statutorily permissible level of control. However, based on the above analysis, Option 3 would have been selected whether it was equal to or above the floor. More stringent control than Option 3 was not selected because the EPA could not conclude, based on currently available information, that the additional emission reduction warranted the additional cost in this case. The control level for Option 4 as compared with Option 3 would achieve an additional emission reduction of 1,100 Mg/yr (1,200 tons) at an additional cost of $4 million/yr. The incremental cost effectiveness of Option 4 relative to Option 3 is $3,900/Mg ($3,500/ton). The final standard retains the proposed requirement for control of process vents with TRE cost-effectiveness values of $11,000/Mg ($9,980/ ton) at new sources. The EPA considered selecting a level of emission reduction more stringent than the level associated with the source-wide floor for process vents at new sources. However, a standard more stringent than the floor component is not being established because the costs were considered high given the very small additional emission reduction available. The additional control would achieve an additional emission reduction of about 100 Mg/yr at a cost of about $4 million/yr, or $47,000 for each additional Mg of emission reduction ($43,000/ton). Therefore, the control level associated with the source-wide floor was considered to represent the maximum reduction achievable for new sources considering cost and other impacts. The final standard for new sources reflects the floor level of control for process vents. (ii) Storage vessels. As described in section V.C.3.b of this preamble, the cost analysis for storage vessels at existing sources was revised after consideration of public comments on the assumptions in the cost analysis. These revisions are reflected in the control cost estimates in table 6. The EPA also revised its estimate of control levels achieved by storage vessels at existing sources. As discussed in section V.C.1 of this preamble, the best controls are IFR or EFR seals without controlled fittings or a 90 percent efficient control device. Because these controls are less economically efficient than the proposed option, which was based on the existing requirements in 40 CFR part 60 subpart Kb, the EPA did not develop a regulatory alternative corresponding to floor control levels for all storage vessels at existing sources. Instead, the regulatory alternatives in table 6 reflect the combination of: (1) The proposed control requirements for vessels, which at the time of proposal were equipped with less efficient controls than the control at the revised floor and (2) the floor control for vessels, which at the time of proposal were equipped with the floor controls. The alternatives were structured in this manner because the EPA could not conclude, based on currently available information, that requiring replacement of existing well- operated and maintained controls that met the control efficiency achieved by sources at the floor was justified. This additional control was estimated to cost about $38,000 for each additional Mg of emission reduction achieved ($34,000/ton). For small storage vessels at existing sources, the maximum potential reduction of 380 Mg/yr would cost about $22 million/yr, or $58,000 for each additional Mg ($52,000/ton). Due to the relatively high incremental costs and low emission reductions of these alternatives, the EPA believes that the control level for the small storage vessels component of the source-wide floor for existing sources represented the maximum reduction achievable considering cost and other impacts. As discussed in section III.B.3 of this preamble, the EPA is not taking final action at this time regarding medium vessels at existing sources. For large storage vessels at existing sources, the EPA considered but rejected changing the control levels from the proposed requirements. The selected control level achieves an additional 3,100 Mg/yr (3,400 tons/yr) emission reduction above Option 1 at an additional cost of $5 million/yr, or about $1,600 for each additional Mg ($1,400/ton). Another consideration was that the selected control requirements are consistent with the requirements in the NSPS for storage vessels (40 CFR part 60, subpart Kb). The more stringent control option, Option 3, was not selected because although it would achieve roughly an additional 4,000 Mg/yr (4,400 tons/yr) emission reduction, the additional cost would be substantial ($15 million/yr). This would be equivalent to about $4,000 for each additional Mg of emission reduction ($3,600/ton). The EPA could not conclude, based on currently available information, that the additional emission reduction warranted the additional cost in this case. The control decisions for storage vessels at new sources were also reexamined. The regulatory alternatives in table 7 reflect minor revisions made to the cost analysis as a result of public comments. After considering the alternatives and the associated impacts, the EPA concluded that the proposed requirements represented the maximum reduction achievable considering costs and other impacts. More stringent control than the proposed levels would not reduce HAP emissions significantly enough to warrant the increase in control costs. For small and medium vessels at new sources, none of the alternative control options more stringent than the floor components were selected. After considering the emission reductions, costs, and other impacts of the alternatives, the EPA determined the cost to achieve the additional reduction was high given the very small potential emission reductions. Additional control would reduce emissions from medium storage vessels by less than 20 Mg/yr (22 tons/ yr) at an additional cost of about $750,000/yr, or $47,000 for each additional Mg. For the small storage vessels segment of the population, further control would result in less than 10 Mg/yr (11 tons/yr) emission reduction at an added cost of about $2.3 million/yr or $336,000 for each additional Mg. Therefore, due to the relatively high incremental costs and low incremental emission reductions, the EPA determined that the control level for the small and medium storage vessels components of the source-wide floor for new sources represented the maximum reduction achievable considering cost and other impacts. For large storage vessels at new sources, the EPA concluded that the proposed control levels represented the maximum reduction achievable considering costs and other impacts. The control requirement for large storage vessels is estimated to achieve an emission reduction of 1,700 Mg/yr (1,900 tons/yr) of HAP's compared to emissions that would occur without the standard. This represents an 84 percent reduction from this segment of the SOCMI storage vessel population. The annual cost to achieve this reduction is about $2.9 million and the average cost effectiveness of this control is $1,700/Mg ($1,500/ton). More stringent control was not selected because the additional emission reduction of 3 Mg/yr achieved through further control is not significant, given the additional cost ($300,000/yr). This cost was judged to be disproportionately high. (iii) Transfer operations. No changes were made to the estimates of emissions or control costs for transfer operations. The final transfer operations control requirements for both existing and new sources are unchanged from the proposed requirements. More stringent control was not selected because the small additional emission reduction that could be achieved was disproportionate to the cost. The incremental cost effectiveness of the additional emission reduction that could be achieved is $54,000/Mg. (iv) Process wastewater. As discussed in the proposed notice of rulemaking (57 FR 62643-62645), there were a number of issues regarding the emission and control cost estimates that the EPA was evaluating at the time of proposal. The EPA has completed its evaluation of these issues, and section V.G.4 of this preamble summarizes the basis for the final estimates for SOCMI sources subject to the HON. A more detailed description of the analysis and basis for the final estimates is provided in the BID and docket A-90-23. The emission and control cost estimates provided in tables 6 and 7 reflect the revised emission and cost estimates for process wastewater. The revised estimates are approximately 20 percent lower than the estimates presented at proposal (57 FR 62629-62630). The EPA reexamined the proposed control requirements in light of these changes and public comments on the stringency of the standard. After considering the alternatives and the associated impacts, the EPA concluded that the proposed control criteria for process wastewater streams at existing sources (flow of 10 lpm or greater and VOHAP concentration of 1000 ppmw) represent the maximum reduction achievable considering costs and other impacts. More stringent control than the proposed levels would not reduce HAP emissions significantly enough to warrant the increase in control costs. Alternative control Options 2 through 4 were not selected because the additional emission reduction achieved through further control was not significant, given the costs and the uncertainty regarding the characterization of SOCMI wastewater systems. Specifically, control of wastewater streams with a flow rate of 5 lpm or greater and a VOHAP concentration of 800 ppmw (Option 2) was estimated to result in about 700 Mg/yr (770 tons/yr) additional reduction at a cost of about $2.9 million/yr. This control option has an incremental cost effectiveness of $4,300/Mg ($3,900 ton). Options 3 and 4 achieve only a small additional emission reduction at incremental cost effectiveness values of $13,400/Mg and $24,000/Mg ($12,100/ton and $21,600/ton). Given the technical uncertainties that exist regarding the representation of SOCMI wastewater streams and industry practices in design of wastewater collection and treatment systems, it is uncertain whether any of the alternative control options considered would result in additional emission reductions. The regulatory alternatives considered for process wastewater streams at new sources were a combination of the floor control requirement for organic HAP's with volatilities similar to benzene (see table 8 of subpart G for the list of organic HAP's) and control alternatives for the less volatile organic HAP's (see table 9 of subpart G for the list of organic HAP's). Table 7 shows the emission reductions and costs associated with the floor control for the table 8 organic HAP's combined with the emission reduction and costs for control of total VOHAP concentrations of either 1,000 ppmw (Option 2) or 5 ppmw (Option 3). After considering the alternatives and the final emission and control costs, the EPA concluded that the control requirements in Option 2 are achievable. The control requirements for new source wastewater streams would apply to 3 sets of streams: Streams with flow rates of 0.02 lpm or greater and a VOHAP concentration of 10 ppmw or greater of organic HAP's listed in table 8 of subpart G; and streams with a flow rate of 10 lpm or greater and a VOHAP concentration of 1000 ppmw or greater of organic HAP's listed in table 9 of subpart G; and any stream with a VOHAP concentration of 10,000 ppmw or greater of organic HAP's listed in table 9 of subpart G. The control level was selected considering the emission reduction achieved by the alternative control options for HAP emissions and considering the criteria enumerated in Section 112(d) of the Act. The control requirements of Option 2 are estimated to achieve an emission reduction of 13,500 Mg/yr (14,800 tons/yr) compared to emissions in absence of this rule. This represents an 82 percent reduction from uncontrolled emission rates. The annual cost to achieve this reduction is about $12.8 million. Option 2 is estimated to achieve an emission reduction of about 3,200 Mg/yr (3,500 tons/yr) of HAP emissions above Option 1 (the floor). This control would cost an additional $2.8 million/yr with an average cost-effectiveness value of $948/Mg ($860/ton). A more stringent level of emission limitation was not selected because control beyond Option 2 is estimated to achieve only a small additional emission reduction. The further control would reduce emissions by an additional 400 Mg/yr (440 tons/yr) of HAP and would cost about $24 million per year, an increase of about $11 million per year over the cost of Option 2. Because the cost is disproportionately large compared to this additional emission reduction, the EPA did not select the more stringent control option for the standard. b. Summary of control decisions. In summary, the selected control provisions are estimated for the well- characterized processes to reduce emissions from existing sources by 312,000 Mg/yr (343,000 tons/ yr) and new sources by 61,300 Mg/yr over emissions that would occur in absence of this rule. The cost of this control is estimated to be about $107 million/yr for existing sources and $32,300/yr for new sources. The cost of the monitoring, recordkeeping and reporting requirements associated with the controls is estimated to be $68 million/yr. Tables 6 and 7 also show the emission reduction and cost associated with the maximum reduction that could be achieved. For existing sources, only an additional 10,000 Mg/yr (11,000 tons/yr) emission reduction could result, and this would cost an additional $103 million/yr. Similarly, for new sources, the additional emission reduction is about 400 Mg/yr (670 tons/yr) and this would cost $19 million/yr more than the selected control requirements. The EPA considers the selected standard to be the maximum reduction achievable considering costs and other impacts. [As discussed in previous sections, the EPA is deferring decision on control of medium-sized storage vessels at existing sources. Thus, the costs and emission reductions presented in table 6 may be slightly overstated.] 3. Selection of Requirements a. Process vents. This section discusses the following issues related to the selection of requirements for process vents: 95-percent control vs. 98-percent control for existing sources, 98-percent control for existing sources, 98-percent control for organic HAP's, and the halogenated stream limit. (i) 95-Percent Control vs. 98-Percent Control for Existing Sources. For the final rule, the EPA maintains the same position as at proposal that existing control devices must achieve an organic HAP reduction of 98 percent or 20 ppmv (measured as total organic HAP or TOC). Several commenters suggested that facilities with an existing control device achieving 95 percent reduction be allowed to operate for a period of time (e.g., 10 years) or until a replacement is necessary. One commenter acknowledged that emissions averaging could be used to make up the difference between 95 percent and 98 percent, but that emissions averaging may not be a viable option in all cases, for example at small production facilities. Available information shows that controls achieving 98 percent reduction for Group 1 process vents are in use at a significant number of existing sources, and are part of the MACT floor. Thus, the standard must require 98-percent reduction. This level of control is required by previous NSPS and several state regulations. For those existing process vent control devices that are achieving less than 98 percent, the EPA has provided emissions averaging as an alternative compliance option. An emission credit from control of another emission point in the facility can be used to offset the emission debit generated by the use of a process vent control device with less than 98 percent efficiency. For small production facilities, the magnitude of emission debit generated by controlling process vents to efficiencies lower than 98 percent should be small. Therefore, emissions averaging should still be a viable option for these facilities. Facilities may also have other options for control of Group 1 process vents. In some cases, addition of supplemental fuel and modification of control device operating conditions can allow existing devices to achieve 98 percent. In other cases, process modifications to raise the TRE to greater than 1.0 may also be a feasible means of compliance. (ii) 98-Percent control for organic HAP. For the final rule, the EPA maintains the same position as at proposal that the reference control technology (RCT) of combustion can achieve at least 98-percent reduction for total organic HAP. The 98-percent reduction level applies to both process vents and transfer operations. One commenter said that the EPA had not demonstrated that RCT achieves a 98-percent reduction for each HAP and that the efficiency appeared to be based on VOC control levels for previous NSPS. However, several commenters said that the reduction was achievable or that the RCT can provide greater than 98-percent reduction and that at least 99.9-percent reduction should be required. The EPA would first like to reiterate that control by thermal oxidation is not specifically required by the HON process vents provisions. Thermal oxidation is simply the reference control technology whose performance level must be met by any controls intended to comply with the HON process vents provisions. The commenter correctly states that 98-percent control is based on studies used to determine VOC control levels for past NSPS and has not been proven by testing for each individual HAP. These two issues do not weaken the EPA's decision for 98-percent control of HAP's for the following reasons: (1) Nearly all HAP's covered by this rule are also VOC's; and (2) HON compliance is not based upon control of each individual HAP. Compliance with the HON may be based upon measurements of either total organic HAP or TOC. Clearly, a control device might have a higher level of control for one particular HAP than for another, but compliance is based on the overall reduction of total organic HAP or TOC. The 98-percent level of control was chosen because it has been shown to be uniformly achievable by well-designed and operated combustion devices. As stated earlier, test data to demonstrate efficiency in a thermal incinerator are not available for each individual HAP. However, the efficiency conclusions for a thermal incinerator (98-percent reduction or an outlet concentration of 20 ppmv) were based on test data using the most difficult VOC compounds to combust, which included several organic HAP's. Therefore, it was concluded that the 98-percent reduction can be achieved for total organic HAP for all well-designed and operated systems. The EPA recognized that thermal incineration may achieve greater than 98- percent reduction in some cases, but test data shows that levels greater than 98 percent may not be uniformly achievable under all operating conditions. (iii) Halogenated streams limit. For the final rule, the EPA has determined that a mass limit is more appropriate for identifying halogen streams that require control of acid gases. The mass limit format will result in a more efficient control approach for acid gas formation and will provide greater flexibility for compliance. This has been changed from proposal where a halogen stream was defined by a concentration limit. Several commenters requested that a mass limit be used in lieu of a concentration for determining if a process vent stream was halogenated or nonhalogenated so multiple process vent streams could be controlled in a common header system. Several commenters also requested a mass limit so flares could be used to control vent streams which contained a small mass rate of halogen compounds. Some commenters cited an existing state regulation in Texas and RCRA rules that were based on a mass limit. Other commenters objected to the requirement to use a scrubber following a combustor to achieve the specified halogen reduction. They noted that other control device combinations, such as a scrubber before a flare, could achieve the same results for some process vent streams. The EPA agrees with the commenters, and a mass limit for defining halogen streams was incorporated in the final rule. The mass limit will provide greater flexibility for compliance. The data used to evaluate the proposed concentration limit were used in this reassessment to determine a mass limit for promulgation. This change is consistent with the demonstrated scrubber performance and not a change in the intended stringency of the rule. The rule has been revised to define a halogenated stream as a process vent stream containing 1.0 lb/hr or greater of halogen atoms. If Group 1 halogenated streams are combusted, the rule requires a 99-percent reduction of total halogen and hydrogen halides or a reduction of halogen and hydrogen halide emissions to less than 1.0 lb/hr. If halogen controls were installed prior to proposal, these are required to achieve 95-percent reduction or reduce emissions to 1.0 lb/hr. A commenter noted that State rules require 95-percent control. The EPA did not include costs for replacing existing scrubbers that achieve between 95- and 99-percent removal in the national impact estimates, and it would not be reasonable to require replacement of existing scrubbers given the small additional percent emission reduction that would be achieved. The rule has been reworded so that only the emission limit is specified rather than also specifying that a scrubber must be used after a combustor. The rule has also been reworded to allow owners or operators flexibility to reduce halogen atom mass flow rate of a Group 1 process vent stream to less than 1.0 lb/hr before combustion (thereby becoming nonhalogenated) and use any type of organics control device (including a flare) to combust the stream. b. Storage Vessels--(i) Vapor pressure criteria for large storage vessels--The final rule maintains the same applicability criteria (i.e., vapor pressure and storage vessel size) that were specified in the proposed rule as MACT for large storage vessels located at both new and existing sources. Two commenters requested that the vapor pressure criterion for determination of Group 1 status of large storage vessels be increased (i.e., reduced in stringency). The commenters objected to the EPA's selection of options above the floor because, in the commenters' view, the options were not cost-effective. The commenters asserted that the EPA's cost analysis had underestimated the actual cost of compliance by underestimating the following costs: (1) The cost of cleaning and degassing storage vessels; (2) The capital cost for IFR's; (3) The installation cost for retrofitting fixed roof tanks with IFR's; and (4) The cost for installing a condenser on a fixed roof storage vessel. Regarding the cost of cleaning and degassing storage vessels, the commenters contended that the EPA's cost estimate was low because: (1) It did not include the cost of hazardous waste disposal; and (2) it was based on the cost of cleaning and degassing tanks containing gasoline and light petroleum products. Regarding the cost of IFR's, the commenters contended that the EPA's capital costs for the installation of IFR's were low for two reasons: (1) The EPA's estimated capital costs, which are based on vendor quotes, were lower than the vendor quote obtained by the commenter; and (2) in general, vendor quotes underestimate the installation costs for IFR's because they do not account for additional tank repairs that are discovered after the tank has been emptied and cleaned for retrofit. Regarding the cost of installing a condenser on a fixed roof storage vessel, one commenter contended that the EPA's cost did not incorporate additional start-up costs, such as testing the operation of a new condenser after installation. The EPA determined that the costing equation used in the proposal analysis for cleaning and degassing should be revised to include the cost of hazardous sludge disposal. These costs have been incorporated into the impacts analysis for the final rule. Regarding the EPA's costing equation for cleaning and degassing storage vessels (including hazardous sludge disposal), the EPA had its equation reviewed prior to proposal by companies that perform cleaning and degassing for the chemical industry. The EPA concluded that the equation is representative of the cost for the chemical industry. The commenters did not provide adequate detail to demonstrate that the cost for the chemical industry would generally be higher than EPA's estimate. The EPA determined that the commenters' capital cost estimates for internal floating roofs are higher than EPA's estimates because the commenters were addressing the capital cost of fiberglass internal floating roofs. The EPA's analysis was based on aluminum internal floating roofs, which are much less expensive than fiberglass IFR's. However, if at baseline a fixed roof storage vessel stores a liquid that is not compatible with an aluminum IFR, the EPA estimated the cost of installing a condenser, rather than a fiberglass IFR, for the fixed roof vessel. The EPA's cost of a refrigerated condenser is, on average, equivalent to the cost for a fiberglass IFR. The EPA's cost equation for installing an IFR on a fixed roof storage vessel, which is based on vendor quotes, already accounts for those tank changes that are directly associated with the installation of the IFR (i.e., the cost of cutting openings and vents). The EPA does not consider the additional tank changes suggested by the commenters (e.g., upgrading the column supports) to be directly related to the retrofit or to be applicable to the average retrofit for compliance with the rule. Therefore, the EPA will continue to utilize its vendor quotes for installation costs for IFR's. The EPA determined that it had underestimated the start-up costs for installing condensers on fixed roof storage vessels (e.g., the cost of testing a new condenser to ensure that it achieves the required temperature). In the proposal analysis, the EPA had used the costing factor provided in the EPA's OCCM: Chapter 8--Refrigerated Condensers published in November 1991, for installing a packaged condenser system. This factor did not account for the start-up cost mentioned by the commenters. The EPA has revised its installation cost equation for condensers to include the OCCM's costing equation for installing a nonpackaged condenser system. This revised equation accounts for the additional start-up costs for installing a condenser. (ii) Performance of existing control equipment on storage vessels at existing sources. For the final rule, the EPA has revised its assessment of the performance achievable by the control equipment for storage vessels at existing sources. Refer to section V.C.2. of this preamble for further discussion of how this issue relates to the MACT floor for existing sources. Two commenters recommended changing the RCT requirement for condensers to specify 90-percent control for storage vessels at existing sources. The commenters contended that most existing refrigerated condensers on storage vessels at existing sources can achieve only 90- to 93-percent control and would therefore have to be replaced with new condensers that could achieve 95-percent control. The EPA has concluded that most existing refrigerated condensers serving storage vessels at existing sources are achieving 90- to 93- percent control. At proposal, the EPA had assumed that these existing condensers could be adjusted to achieve 95-percent control through changes in coolant temperature. However, after reevaluating the available information, the EPA has concluded that not all of the existing condensers achieving 90-percent control can be adjusted to achieve 95-percent control. Additionally, the EPA has determined that IFR's controlling emissions from fixed roof storage vessels at existing sources do not have controlled fittings. Therefore, the final rule establishes MACT for storage vessels at existing sources as 95-percent emissions reduction, except where control devices achieve 90- to 95-percent emissions reduction. The final rule does not require upgrade of an existing control device, provided the device was installed on a storage vessel on or before December 31, 1992 and is designed to reduce inlet emissions of total organic HAP's by at least 90 percent. Refer to section V.C.2. of this preamble for further discussion of how this issue relates to the MACT floor for existing sources. c. Transfer operations. The analysis of the MACT floor level of control and the control requirement for transfer operations did not change for the final rule. Owners or operators of transfer racks that load 650,000 l/yr or more of organic HAP's with a rack-weighted partial pressure of 10.3 Kpa or greater are required to control emissions by 98-percent reduction, use a flare, or use vapor balancing. Facilities using vapor balancing can also choose to exclude the rack being vapor balanced from compliance with the transfer provisions. Some commenters supported the stringency level set for transfer operations, including the definitions of Group 1 and Group 2 transfer racks, the level of control (i.e., 98 percent), and the allowance of vapor balancing. However, one commenter contended that the EPA did not identify the best-controlled transfer racks. The commenter asserted that the EPA identified vapor balancing as a superior control technology since transfer racks using this technology are exempt, but the EPA did not identify vapor balancing as the floor or MACT. Based on the data available for the floor analysis, the EPA concluded that the average of the top 12 percent of the transfer racks achieve 98-percent reduction. The 98-percent value was based on racks subject to the Benzene Waste NESHAP. Using vapor balancing with vapor collection on a transfer rack exempts the facility from the HON transfer provisions because vapor balancing reduces emissions by 98 percent or better, based on a technical analysis. However, data were not available to identify if vapor balancing was being used on a sufficient proportion of SOCMI transfer operations to constitute a floor level of control. d. Process wastewater--(i) Lists of hazardous air pollutants. Several commenters requested clarification of the difference in the lists of organic HAP's: (1) In the Act; (2) in table 2 of subpart F; and (3) in tables 8 and 9 of subpart G. The EPA clarifies that the Act includes a list of 189 HAP's from which the EPA has identified 112 organic HAP's that are emitted from SOCMI processes (table 2 of subpart F). From the list of 112 organic HAP's in table 2 of subpart F, the EPA has identified 76 organic HAP's that exist in water and that are most likely to be emitted from wastewater. These 76 organic compounds are listed in table 9 of subpart G. Table 8 of subpart G is a subset of table 9 and includes organic HAP's that volatilize from wastewater at a rate approximately equal to or greater than benzene. (ii) Definition of ``wastewater.'' In the proposed rule, the definition of ``wastewater'' contained several terms including process fluid, process wastewater, maintenance wastewater, and maintenance- turnaround wastewater. These terms were defined within the proposed definition of ``wastewater.'' In the final rule, the EPA has revised the definition of wastewater in Sec. 63.101 of subpart F to clarify the scope of the EPA's original intent. As part of this clarification, the term ``process fluid'' has been removed from the definition of ``wastewater,'' because commenters were confused that process fluids were considered to be wastewater before they left the process unit equipment and entered the individual drain system. The EPA clarifies that any fluid must exit the process unit equipment before it may be a wastewater stream subject to the HON. The term ``maintenance-turnaround wastewater'' also has been deleted from the definition of ``wastewater'' because all maintenance-related wastewater is now included in the definition of ``maintenance wastewater.'' In the final rule, the definitions of both ``wastewater'' and ``maintenance wastewater'' are in Sec. 63.101 of subpart F. The revised definition of ``wastewater'' in the final rule reads as follows: Wastewater means organic hazardous air pollutant-containing water, raw material, intermediate, product, by-product, co-product, or material that exits equipment in a chemical manufacturing process unit that meets all applicability criteria specified in Sec. 63.100 (b)(1) through (b)(3) of subpart F and either: (1) Contains at least 5 ppmw total volatile organic hazardous air pollutants and has a flow rate of 0.02 lpm or greater; or (2) contains at least 10,000 ppmw total volatile organic hazardous air pollutants at any flow rate. Wastewater includes both process wastewater and maintenance wastewater. Numerous comments were received on the definition of ``wastewater'' in section 63.101 of subpart F. All responses to these comments are located in Sec. 4.1.2 of BID volume 2B. Commenters expressed concern about the following issues: (1) The EPA should specify a percentage of water in order for a stream to be considered a wastewater subject to the HON; (2) The definition of ``wastewater'' should not include ``process fluid,'' ``product,'' and ``intermediate stream''; and (3) The EPA should narrow the scope of the wastewater definition because products that are within a process unit should not be regulated. The EPA has not specified a percentage of water that must be present in a wastewater stream in order for the stream to be a wastewater stream. The EPA intends for the HON to regulate as wastewater any stream that: (1) Exits process unit equipment; and (2) meets the concentration and flow rate criteria that are specified in the definition of wastewater. The EPA has determined that such wastewater streams have a significant potential for emissions and should therefore be regulated. Because the EPA intends to regulate wastewater streams that are generated when organics exit process unit equipment, the EPA continues to include the terms ``product'' and ``intermediate'' in the definition of ``wastewater.'' If an owner or operator chooses to discharge from process unit equipment either a product or intermediate that also meets the definition of a ``wastewater'' (i.e., flow rate and VOHAP concentration), the EPA wants to ensure that emissions from such wastewater streams are controlled. If a product or intermediate stream has not exited the process unit equipment, then such streams cannot meet the definition of ``wastewater'' in Sec. 63.101 of subpart F, and therefore are not subject to the wastewater provisions in the HON. The EPA has deleted the term ``process fluids'' from the definition of ``wastewater'' because commenters stated that process fluids also could mean fluids within a process unit. (iii) Basis of standard. In the final rule, the EPA retains steam stripping as the RCT. Numerous commenters opposed basing control of HAP emissions from wastewater on steam stripping and recommended biological treatment as the RCT for the following reasons: (1) The most common type of wastewater treatment currently employed by existing SOCMI sources is biological treatment; (2) Many of the HAP's listed in table 9 of subpart G are not volatile and cannot be removed by steam stripping, but can be biologically degraded; and (3) The inclusion of biological treatment as an RCT would be consistent with the Benzene Waste NESHAP requirements. The EPA selected steam stripping as the RCT because it is the most universally applicable treatment technology for removing volatile organic HAP's from wastewater. The EPA is aware that many SOCMI facilities use biological treatment units for wastewater treatment. However, in general, compounds that are not easily steam stripped, but are readily biodegraded, are not being regulated by the HON. The HON regulates volatile organic HAP's and volatile organic HAP's can be treated by steam stripping. Not all of the regulated compounds are significantly biodegradable, because volatility does not correlate with biodegradation efficiency, as it does with steam stripping efficiency. When reviewing biological treatment as the potential RCT, the EPA determined that variability in performance is significant. For example, the amount of emissions reduction achieved by biological treatment, even for biologically degradable compounds, will vary among SOCMI sources due to ranges in operating and design parameters, such as the biological degradation rate, surface area of the unit, aeration rate, hydraulic residence time, and the active biomass concentration. A well- operated and well-maintained biological treatment system can achieve reductions as high as 99-percent HAP destruction. However, the variability in performance makes it difficult to quantify a required emission reduction for the purpose of setting a standard. Emission reductions for biological treatment systems can only be determined on a site-specific basis. The EPA emphasizes that SOCMI sources using biological treatment can comply with the rule by consistently achieving the required emission reduction. The EPA has reviewed the Benzene Waste NESHAP and has determined that the equipment standard for the use of a biological treatment unit in the Benzene Waste NESHAP would not achieve comparable emission control for all 76 HAP's regulated by the HON wastewater provisions. This option may be used in combination with other treatment options, but all wastewater streams must be conveyed or handled in individual drain systems or waste management units that limit HAP emissions to the atmosphere as required by Secs. 63.133 through 63.137 of subpart G. The only wastewater streams that may be conveyed or handled in uncontrolled individual drain systems or waste management units are: (1) Group 1 wastewater streams that have already been treated and have achieved compliance with one of the HON treatment options in Sec. 63.138 of subpart G; and (2) Group 2 wastewater streams. As required in the other wastewater compliance options, facilities using this option must comply with the emission suppression requirements in Secs. 63.133 through 63.137 for all wastewater streams except those wastewater streams that are already in compliance. In the final rule, the EPA has included an additional compliance option for the use of biological treatment. Under this treatment option, an owner or operator is required to control all wastewater streams in accordance with Secs. 63.133 through 63.137 and achieve a 95-percent reduction in total HAP mass for all wastewater that is treated in the biological treatment system. (iv) Clarification on the Use of the Terms ``HAP'' and ``VOHAP''. In response to comments, the EPA clarifies the use of the terms ``VOHAP concentration'' and ``HAP'' to reflect the proper use of the terms throughout the preamble, regulation, and BID documents. The terms ``volatile organic hazardous air pollutant concentration'' or ``VOHAP concentration'' mean the concentration of an individually-speciated organic HAP in a wastewater stream or a residual as measured by Method 305. The term ``VOHAP concentration'' does not refer to the lists of organic HAP's in tables 8 and 9 of subpart G. The wastewater provisions of the HON regulate emissions from wastewater of those organic HAP's listed in table 8 for new sources and in table 9 for new and existing sources. The applicability of the requirements in the HON to wastewater streams is based on the VOHAP concentration of the HAP's present in the wastewater stream. In addition to using Method 305, the VOHAP concentration of a compound can be calculated by multiplying the HAP concentration of the compound by the compound-specific fraction measured (Fm) value listed in table 34 of subpart G. (v) Point of Generation. In the final rule, the conceptual basis for the point of generation has not changed from the proposed rule. However, in consideration of the comments, the EPA has clarified the definition. The point of generation is located where process wastewater exits the chemical manufacturing process unit equipment. Numerous commenters requested clarification on both the proposed definition of ``point of generation'' and the location where sampling for the flow rate and VOHAP concentration were permissible. The following comments were submitted: (1) The EPA should not define the point of generation as ``prior to mixing''; (2) The point of generation should be after the last recovery device and before discharge to a wastewater treatment or disposal system; (3) The EPA should delete or explain the use of the term ``integral to the process unit''; (4) The EPA should clarify that the point of generation is at the point where material exits the process unit and enters the individual drain system; (5) To be consistent with RCRA, the point of generation should be the first point downstream of the process unit where emissions can enter the atmosphere; and (6) Sampling should be allowed downstream of the point of generation in situations where the point of generation is either within a closed-pipe system or sampling could be dangerous to workers. The basic foundation of the proposed provisions for process wastewater is to identify wastewater streams for control and treatment based on VOHAP concentration and flow rate at their point of generation, which is where the wastewater exits chemical manufacturing process unit equipment. This approach focuses control efforts on the wastewater streams with the highest HAP loadings. If dilution prior to a control determination were allowed, some wastewater streams that would have required control based on the VOHAP concentration criteria would not meet the VOHAP concentration criteria at the point of generation for control and would not be treated. Thus, the EPA has retained the concept of ``prior to mixing'' to avoid the dilution of wastewater streams. However, the EPA allows the owner or operator to make corrections for changes in VOHAP concentration and flow rate using engineering calculations. In consideration of commenter concerns, the final rule clarifies the EPA's original intent in Sec. 63.144 of subpart G to reduce the sampling and analysis burden for industry while still meeting the EPA's objectives. The point of generation remains a single location in the final rule. However, sampling to determine the characteristics of a wastewater stream (i.e., VOHAP concentration and flow rate) may be accomplished either at the point of generation or downstream of the point of generation. If wastewater characteristics are determined downstream of the point of generation, the owner or operator must correct for: (1) HAP losses due to volatilization; (2) Reduction of VOHAP concentration or changes in flow rate by mixing with other water or wastewater; or (3) Reduction of VOHAP concentration or flow rate by treatment or handling to destroy or remove HAP's. The final rule also incorporates the concept of designating either a single wastewater stream or a mixture of wastewater streams as a Group 1 wastewater stream. This option allows the facility owner or operator to declare that at a designated location downstream of the point(s) of generation, all wastewater streams at this location and upstream are Group 1 and are therefore controlled in accordance with Secs. 63.133 through 63.137. The owner or operator is required to meet all requirements for Group 1 wastewater streams, both upstream and downstream for the designated Group 1 wastewater stream. The advantages to using this option are that no sampling is necessary to make a Group 1/Group 2 determination and a facility can reduce the number of locations where wastewater stream characteristics are determined. By adding the option to designate Group 1 wastewater streams and clarifying the option to determine wastewater characteristics downstream of the point of generation, the EPA has addressed commenter concerns about sampling in closed piping. While the concept of designating Group 1 wastewater streams does not allow any wastewater streams that would be Group 1 at the point of generation to become Group 2 wastewater streams, it does provide an avenue for fewer point of generation identifications than the proposed rule because sampling does not need to be done at the actual point of generation. The EPA encourages owners or operators to sample downstream of the point of generation if sampling from the point of generation could be dangerous to workers or if the point of generation is within a closed- pipe system. In fact, the proposed rule allowed sampling downstream of the point of generation. Because numerous comments indicated that the proposed rule was not clear about where to sample and make Group 1/ Group 2 determinations, the final rule has been clarified. The final provisions now specify that Group 1/Group 2 determinations can be made downstream of the point of generation using sampling, process knowledge, or bench-scale or pilot-scale test data. e. Cooling water. In the final rule, the provisions for monitoring cooling tower and once-through cooling water systems have been modified in response to commenter concerns. In the final rule, the EPA clarifies the definition of heat exchange system (i.e., both cooling towers and once-through cooling systems). A leak in a heat exchange system is no longer identified by a statistically significant increase of 1 percent at a 95-percent confidence level but is identified only by a statistically significant increase of at least 1 ppm at a 95-percent confidence level. In the final rule, the EPA clarifies that sampling for leak detection must be conducted at the inlet and outlet of the cooling tower, not the inlet and outlet of each heat exchanger. For the final rule, a once-through cooling system will not be subject to the HON if it has an NPDES permit with a discharge limit of less than 1 ppm. An NPDES permit with a discharge limit of less than 1 ppm guarantees that the concentration differential across a once-through cooling water system is less than 1 ppm. Furthermore, the EPA realizes that routing the discharge from a steam jet ejector to a cooling tower may cause a concentration differential of 1 ppm across a heat exchange system. Therefore, in the final rule, the EPA includes re-routing the discharge from a steam jet ejector as a means of repairing a leak in a heat exchange system. In response to comments requesting clarification about which HAP's were regulated, the EPA clarifies that water from cooling towers are regulated for the organic HAP's listed in table 2 of subpart F except for four water-reactive HAP's and once-through cooling systems are regulated only for the HAP's listed in table 9 of subpart G. Several commenters were concerned that 15 days was not ample time to repair a leak in a heat exchange system. In response to comments, the EPA has extended the delay of repair for leaks in a heat exchange system from 15 days in the proposed rule to 45 days in the final rule. The final rule allows delay of repair beyond 45 days for situations where the owner or operator can show that emissions from shutdown of a process would be greater than emissions from the leak. Several commenters submitted comments stating that the EPA: (1) Correct or clarify the original intent to require sampling across the cooling tower, not across each heat exchanger; (2) provide an exemption for heat exchange systems with low flows; (3) clarify which HAP emissions are regulated from cooling towers and once-through cooling water systems; and (4) clearly state which parameters are acceptable for monitoring. Numerous commenters suggested alternate ways of testing for a leak in a heat exchange system rather than testing for speciated HAP's, including testing for TOC or total VOHAP concentration, or using surrogate parameters to determine a leak. Having reviewed several sampling parameters and analytical methods, the EPA concludes that: (1) Sampling for total VOC, total HAP, TOC for semi-volatile compounds, or speciated HAP concentration is allowable; and (2) any method listed in 40 CFR part 136 or any other method approved by the Administrator may be used as long as the same method is used on both the inlet and outlet. The EPA concludes that monitoring of surrogate parameters is not sufficient to determine the magnitude of the leak in the cooling tower or once-through cooling system. After analyzing the amount of HAP's that could be emitted if the sampling frequency for leak detection were extended beyond quarterly, the EPA continues to require quarterly monitoring. The rule does not provide an exemption for heat exchange systems with a low flow rate (e.g., 1,000 to 2,000 gpm) because the emissions from such systems are significant if a leak is detected. For example, if a leak at 2,000 gpm is detected after 3 months of leaking, 1.1 tons of HAP emissions could have already been emitted. f. Maintenance wastewater. In the final rule, the EPA requires that all maintenance-related wastewater be managed in the same manner. The definition of ``maintenance-turnaround wastewater'' has been eliminated from the final rule and incorporated into the definition of ``maintenance wastewater,'' which now encompasses all maintenance- related wastewater streams that are subject to the HON. The term ``maintenance wastewater'' in the proposed rule referred to only routine maintenance wastewater. Also, in the final rule, all maintenance-related wastewater streams are subject to the same requirements under the HON. Unlike the proposed rule, the final rule does not require that routine maintenance wastewater be managed in a controlled drain system. In the final rule, the facility's start-up, shutdown, and malfunction plan must include a description of procedures that will ensure that all maintenance wastewater is properly managed and HAP emissions are controlled. These requirements are consistent with what was proposed for maintenance- turnaround wastewater. The EPA received numerous comments opposing the proposed maintenance wastewater provisions, including: (1) Maintenance-related wastewaters are not a significant source of HAP emissions; (2) the control of maintenance wastewater cannot be justified; and (3) there should be a Group 1/Group 2 determination or a de minimis level to determine which maintenance wastewaters are subject to the regulation. Several commenters expressed confusion about the proposed requirements for routine maintenance wastewater and whether or not these maintenance wastewaters were required to be collected in a closed or controlled drain system. Numerous commenters suggested that the requirements for routine maintenance wastewater and maintenance-turnaround wastewater be the same. In the proposed rule, the EPA's original intent was to require good work practices and reduce the burden of implementing the rule by deleting the requirement that the owner or operator must determine if emissions from maintenance wastewater have exceeded a designated de minimis level. Based on comments received, all maintenance-related wastewater is now subject to the same requirements. The EPA is eliminating the provisions which require that routine maintenance wastewater be managed in a controlled drain system. The EPA is not including a Group 1/Group 2 or de minimis level criteria for maintenance wastewater because of the difficulty in determining the concentration and flow rate and the difficulty of enforcement. D. Emissions Averaging This section of the preamble presents the rationale for the emissions averaging provisions (described in section 63.150 of subpart G) and the alternative policies that were considered in developing these provisions. As part of the EPA's general policy of encouraging the use of flexible compliance approaches where they can be properly monitored and enforced, the Administrator is allowing sources the option of using emissions averaging to comply with subpart G. Under particular circumstances, emissions averaging can provide sources the flexibility to comply in the least costly manner while still maintaining a regulation that is workable and enforceable. The EPA's goal in crafting the emissions averaging provisions in the final rule has been to make emissions averaging available to sources faced with some emission points that are particularly difficult or costly to control. At the same time, the EPA has simplified and streamlined the emissions averaging provisions in order to ease the enforcement burden on implementing agencies. The rationale for the specific provisions of the emissions averaging policy is detailed below. In general, the basic structure of the HON emissions averaging policy remains much the same as at proposal. Fundamental elements such as the credit/debit system, kinds of emission points allowed in averages, reference control efficiency provisions, provisions for approval of new devices, and an annual compliance period remain unchanged. However, some provisions have been altered or added in order to sharpen the focus of emissions averaging, ease implementation and administration, and ensure at least the same air quality benefit as point-by-point compliance. For example, the number of emission points that can be included in an average has been limited; banking of credits has been disallowed; actions taken prior to November 15, 1990 or in response to another State or Federal requirement will not be credited; averaging will not be allowed at new sources; and a discount factor of 10 percent will be applied to credits generated by control other than pollution prevention measures. In addition, sources must demonstrate, to the implementing agency's satisfaction, that a proposed averaging plan will not cause an increase in risk or hazard relative to point-by- point controls. All of these changes are discussed in greater detail in the following sections. The EPA included this limited emissions averaging system in the HON to provide sources with flexibility on ways to comply with this standard. The EPA will continue in future standards to seek ways to provide sources with flexibility, while maintaining sources' accountability for meeting health and environmental goals. However, the HON emissions averaging system, and its provisions for interpollutant trading, should not be viewed as setting a precedent for future MACT standards. Moreover, emissions averaging is only one way to provide sources with flexibility. The EPA will determine the proper amount and type of flexibility based on considerations specific to each standard. 1. Legal Basis and Scope of Emissions Averaging a. Legal basis of emissions averaging. For the final rule, the EPA maintains the position that the Administrator has legal authority to permit sources to comply with the requirements of section 112(d) through emissions averaging. Several commenters agreed that the legal basis for emissions averaging is sound, citing justifications such as: (1) Emissions averaging is consistent with section 112(d) of the Act because cost must be considered in setting MACT standards; (2) Section 112(h) requires that a numerical emission limit be promulgated where feasible, leaving it to individual sources to meet the limit; and (3) Averaging will achieve equivalent or greater emission reductions than the rule without averaging. A number of commenters contended that emissions averaging violates the law. Some did not consider it a permissible application of MACT. Others argued that because Group 1 points are left uncontrolled or undercontrolled under averaging, the rule would fail to achieve the maximum achievable emission reductions required under section 112(d). More commenters considered it doubtful that emissions averaging can achieve the same emission reductions as the rule without averaging, and claimed therefore that it does not represent an equivalent compliance option. Some commenters argued that the EPA does not have statutory authority to allow emissions averaging, and that because Congress specified the use of offsets in section 112(g) and not in section 112(d), it is unlikely that averaging was intended for MACT standards. Following a thorough review of all the comments received on this issue, the EPA has concluded that emissions averaging is legally permissible under section 112. As stated at proposal, section 112(d) requires standards to be established for each category or subcategory of sources listed under section 112(c). Such standards shall then be applicable to sources within those categories or subcategories. The statute does not define ``source category,'' nor does it impose precise limits on the Administrator's discretion to define ``source.'' In this case, the Administrator has exercised that discretion to define ``source'' somewhat broadly to include all emission points relating to SOCMI production at a facility. In setting the standard for a category or subcategory, the Administrator is required to determine a floor for the entire category or subcategory, and then set a standard applicable to each source within that category that is at least as stringent as the floor and requires the maximum achievable emission reductions considering certain factors. In determining whether the standard should be more stringent than the floor and by how much, the Administrator is to consider, among other factors, the cost of achieving the additional emission reductions. The statute does not limit how the standard is to be set beyond requiring that it be applicable to all sources in a category, be written as a numerical limit wherever feasible, and be at least as stringent as the floor. Therefore, the relevant statutory language is broad enough to permit the Administrator to exercise discretion to allow sources to meet MACT through the use of emissions averaging provided the standard applies to every source in the category, averaging does not cross source boundaries, and the standard is no less stringent than the floor. In this rule, the Administrator has created an averaging system that stays within those legal parameters. The source has been defined to include all SOCMI processes within a major source, and a standard has been written to apply to all sources in the category as provided by sections 112(d) (1) and (2). This standard is no less stringent than the floor for the category, calculated in accordance with section 112(d)(3), and takes cost and other relevant factors into consideration. The standard applies only to sources in the category, applies to all such sources, is written as a numerical limit where feasible, and averaging can only be conducted within the confines of each individual source, thus ensuring that the standard, as applied to each source, is no less stringent than the floor. In addition, a discount factor is applied when averaging is used, which further ensures that averaging will be at least as stringent as the rule without averaging. Some commenters on the supplemental notice argued that the provisions for limiting the number of points, requiring a hazard or risk determination, and allowing States to exclude emissions averaging without having to follow the section 112(l) rule approval processes are inconsistent with E.O. 12866 (September 30, 1993). The commenters claimed that the Executive Order directs agencies to: (1) Develop regulations that do not impose unacceptable or unreasonable costs; and (2) identify and assess available alternatives to direct regulation, including providing economic incentives to encourage the desired behavior. The EPA maintains that the rule adheres to the spirit of the Executive Order throughout, both by providing the most flexible emissions averaging program that is still enforceable and by allowing numerous different control options for each kind of emission point under point-by-point compliance. These two aspects of the rule provide flexibility to reduce emissions in the most cost-effective manner as encouraged in the Executive Order. b. Emission points allowed in averages. Emissions averaging is allowed across all the emission points, except equipment leaks, within a single existing source, as ``source'' is defined for the SOCMI source category. As such, emissions from the following kinds of emission points can be averaged: process vents, wastewater operations, storage vessels, and transfer operations. Averaging is allowed across these four kinds of emission points in order to provide as much flexibility as possible while maintaining an enforceable standard. No commenters explicitly expressed support for the selection of these particular kinds of emission points to be included in emissions averages. However, the EPA does not interpret this to mean that there was no support. Rather, it is reasonable to assume that commenters who supported emissions averaging in general, but did not explicitly comment on the kinds of emission points available for averaging, supported allowing averaging across all the kinds of points included in the proposal. While some commenters supported the exclusion of equipment leaks from emissions averaging, a number of commenters expressed direct support for allowing equipment leaks in emissions averages. They argued that it is already possible to quantify emissions from equipment leaks sufficiently and suggested ways to establish baseline levels and to overcontrol equipment leaks for credit. However, the EPA has determined that, although methods are available for quantifying emissions from equipment leaks, equipment leaks cannot be included in emissions averages at this time because: (1) The negotiated standard for equipment leaks has no fixed performance level; and (2) neither a reference control efficiency nor allowable emission levels can be established for leaks. Without a reference control efficiency or allowable emissions, debits and credits cannot be established. A few commenters recommended excluding wastewater from averaging as well, because they considered accurate or reliable estimation of wastewater emissions unlikely or impractical. However, the EPA considers the methods for estimating wastewater emissions to be sufficient for averaging. The reliability of estimations is assured because all sources will be using the same emissions estimation approach. The calculation procedures are specified in Sec. 63.150 of subpart G. Also, the final rule clarifies that wastewater streams treated in biological treatment units cannot be used in averages, which was one of the primary concerns raised by commenters. Several commenters also opposed allowing averaging across different kinds of emission points, and recommended that averaging should only be allowed among the same kinds of points. Some of these commenters were concerned that the four kinds of emission points have such different emission characteristics that averaging across the points could alter the dispersion of emissions and thus, their associated impacts. Other commenters were concerned that differences in emission estimation techniques across different kinds of points could be used to calculate credits that may not reflect actual emission reductions. The EPA agrees that characteristics of emission points may affect the dispersion of emissions and associated impacts. However, these differences exist under point-by-point compliance as well, and it is equally likely that emissions averaging could decrease impacts as well as increase them. Similarly, the EPA acknowledges the potential for significant complexity in averaging across different kinds of emission points. In order to prevent inappropriate compliance scenarios, the emissions averaging program relies upon consistent emission estimation techniques and data from actual operations. In addition, implementing agencies may require sources to consider differences in dispersion and associated impacts as part of the risk review that is now required when approving emissions averages. c. Averaging at new sources. Emissions averaging is not allowed as a compliance option for new sources. The decision to limit emissions averaging to only existing sources represents a departure from the proposal, which envisaged emissions averaging at both existing and new sources. While one commenter specifically supported allowing emissions averaging at new sources, a number of commenters specifically opposed allowing averaging at new sources. The EPA concurs with those commenters who maintained that new sources have historically been held to a stricter standard than existing sources, because it is most cost- effective to integrate state-of-the-art controls into equipment design and to install the technology during construction of new sources. One reason for allowing averaging is to permit existing sources flexibility to achieve compliance at diverse points with varying degrees of control already in place in the most economically and technically reasonable fashion. This concern does not apply to new sources which can be designed and constructed with compliance in mind. In addition, as averaging must be limited to an individual source, there could not be averaging between new and existing sources, even under the proposal. Therefore, not allowing averaging at new sources does not affect an existing sources' ability to use averaging. d. Broader Scope of Emissions Averaging. In the final rule, the EPA is retaining the position taken at proposal that emissions averaging will be permitted only among emission points that are within the SOCMI source category. The EPA requested comment at proposal on a broader averaging alternative that would have allowed averaging of emissions from any point located within a contiguous facility, including both SOCMI and non-SOCMI emission points. Having considered all of the arguments put forth by commenters, both supporting and opposing broader averaging, the EPA has concluded that emissions averaging on a broader scope cannot be legally justified. The fundamental problem with the broader averaging approach is that it allows averaging among multiple sources. The HON has defined the source, for the purposes of this standard, as the collection of SOCMI emission points within a major source. Many major sources containing such points will also contain other points not covered by this standard but to be covered by later, different MACT standards. Each of these standards will have a separate floor, and the statute requires that each standard be no less stringent than its floor. If averaging were allowed between sources covered by two separate standards, it is likely that one of the sources involved in the average would be emitting HAP's at a level that violates the standard applicable to it. Thus, averaging between multiple sources in different categories is not legally defensible. Similarly, allowing averaging between new and existing sources at the same facility would also likely lead to one source failing to meet its applicable standard. There are separate MACT standards with separate floors for new and existing sources within the HON, just as there will be separate standards for sources in different categories at the same site. An average that included sources with different floors and different standards cannot be reconciled with the statutory requirement that each source in the category comply with the applicable standard. The proposal discussed the possibility of defining ``source'' differently for purposes of sections 112 (d) and (i) of the Act. While the EPA believes that there is broad discretion to define ``source'' under section 112, and the term can quite legitimately have different meaning in different parts of the Act (see, Chevron, U.S.A. Inc. v. NRDC, 467 U.S. 837 (1984)), the EPA does not believe that it is appropriate to apply different definitions in the present context. The source to which a MACT standard applies under section 112(d) is the same source that is covered by the compliance requirements of section 112(i). Clearly, section 112(i)(3) provides for setting compliance dates for categories of sources for which a MACT standard has been set, and section 112(d) requires standards to be set for categories of sources. It is not reasonable to argue that compliance with a standard can be achieved beyond the boundaries of the individual sources that comprise the category. 2. Interpollutant Trading and Hazard Assessment or Risk Analysis The emissions averaging provisions in the proposed rule allowed averaging across all HAP's covered by the HON. The EPA was aware that these HAP's are associated with a variety of different effects at different levels of exposure. Therefore, at proposal, comment was requested on the appropriateness of allowing interpollutant trading in an unrestricted manner, as well as on two potential approaches for considering toxicity. Several commenters maintained that unrestricted interpollutant trading should be allowed because: (1) So long as pollutants are listed in section 112(b) of the Act, they should be freely available for averaging; (2) standards under section 112(d) must be based on the achievability of control technologies instead of hazard or risk; (3) accounting for toxicity would add administrative complexity; and (4) the understanding of HAP toxicity is so limited that adjusting for trades would be difficult, if not impossible. In contrast, several commenters criticized interpollutant trading, especially trading that does not take toxicity into account, citing reasons such as: (1) It could endanger public and worker health; and (2) The understanding of HAP toxicity is so limited that interpollutant trades should not be allowed at all. In weighing the concerns expressed at proposal, the EPA agrees that emissions averages should achieve at least a comparable hazard or risk benefit to point-by-point compliance. At the same time, the EPA recognizes the inherent difficulty of devising one set of provisions that would adequately, fairly, efficiently, and simply address these concerns in all circumstances. After careful deliberation on all available options, the EPA has decided to require that sources who elect to use averaging must demonstrate, to the satisfaction of the implementing agency, that compliance through averaging would not result in greater hazard or risk than compliance without averaging. This new provision was introduced in the supplemental notice and has been included in the final rule. The EPA will provide a technical support document to aid implementing agencies in making the demonstration based on existing procedures, but the actual methodology to be used by the source is to be chosen by the implementing agency. This approach gives all implementing agencies the authority to consider hazard or risk in approving averages. It was also recognized that to satisfy a State or local agency that an averaging plan would not increase hazard or risk, a source might have to identify and quantify all the HAP's included in the average. Hence, comment was requested on whether identifying all the HAP's in the emissions streams would pose difficulties for sources, and if so, what those difficulties would be. Several commenters responded to the supplemental notice in favor of requiring sources to conduct hazard or risk assessments claiming that it would better ensure that public health is protected. However, many of these commenters still preferred that emissions averaging not be allowed at all, arguing that: (1) No adequate methodology exists for assessing and comparing hazard or risk in all circumstances; (2) States do not have the knowledge or resources to develop the necessary methodologies; and (3) the new requirement would add to the administrative burden placed on implementing agencies by the rule. Still, several commenters insisted that State and local agencies can and should be allowed to use or develop their own policies and tools for performing the hazard or risk determination. The EPA maintains that methodologies exist for assessing and comparing hazard or risk, which are applicable to this context and appropriate for many emissions averaging scenarios. However, two points require clarification. First, the terms hazard and risk should not be equated. Hazard assessments address toxicity but not exposure. Hazard refers to the intrinsic toxic properties of a pollutant, such as potency or the types of toxic endpoints of concern (e.g., cancer, developmental effects). Risk is an integration of hazard and human exposure to the pollutant, used to estimate the type and likelihood of toxic effects associated with a specific pollutant release. Under this rule, the implementing agency can consider either of these factors in determining whether an averaging plan should be approved. Furthermore, the implementing agency may consider ecotoxicity, bioaccumulation, and acute toxicity exposure to organic HAP's when reviewing a hazard or risk determination. However, such considerations are not required. The second point of clarification is that both hazard and risk assessment methodologies carry with them some uncertainty. The issue of uncertainty will be addressed in the forthcoming technical support document. The EPA intends that States should have discretion in structuring their determinations. States that have existing programs may wish to continue using their established procedures; in fact, the new requirement was designed largely because some States already use hazard or risk assessments to evaluate HAP control. The new requirement may be seen as an additional burden by some implementing agencies, but as stated previously, an assessment of hazard or risk is necessary to determine that averaging does not result in an increase in hazard or risk. Several commenters responded in opposition to the provision requiring hazard or risk assessments and cited some of the reasons stated at proposal for opposing any kind of toxicity weighting. The commenters reiterated that: (1) Hazard or risk considerations are inappropriate in section 112(d) standards, which should be technology- based; (2) sources' compliance burdens would be increased, which would decrease the cost effectiveness of using averaging; and (3) there is no evidence that emissions averaging will increase hazard or risk. Some commenters on the supplemental notice added that hazard or risk assessment methodologies are likely to change after the study of risk assessment by the National Academy of Sciences mandated under section 112(o) of the Act is finished. They argued, therefore, hazard or risk should not be considered until after the study is submitted. The floor and the RCT's for the rule were determined without any consideration of hazard or risk. Emissions averaging represents an alternative to the technology-based system of point-by-point compliance, and as an alternative must be demonstrated to result in equivalent control. This demonstration can consider hazard or risk without violating the intent of section 112(d) of the Act. It is possible that in some cases, having to conduct a hazard or risk assessment may so increase the cost of averaging that it is no longer more cost-effective to average, but the EPA does not think this is likely in most cases because of the limited size of most averages. To address the possibility that an averaging proposal may increase hazard or risk relative to point-by-point compliance, the EPA intends to provide a technical support document that could be used for this hazard or risk demonstration. The EPA recognizes the importance of allowing States substantial flexibility in designing such a demonstration and avoiding a burdensome or prescriptive set of requirements that unnecessarily interfere with averaging. Finally, the Act contains no requirement that hazard or risk considerations be delayed until after the study of risk assessment by the National Academy of Sciences is completed. The statutory requirements and deadlines remain in effect, the study notwithstanding. A number of commenters agreed that the EPA should provide standard guidance on hazard or risk assessments for sources and implementing agencies. Some commenters recommended that the guidance should: (1) Take into account different aspects of HAP toxicity, dispersion, and exposure; (2) resemble guidance for air quality modeling, which defines different approaches for different situations; (3) be developed with States involvement; and (4) establish presumptive minimum levels for State programs to follow. The EPA intends to take these and other recommendations into account before issuing a technical support document. Some commenters supported requiring identification of all HAP's in emission streams for the purposes of conducting the hazard or risk assessment because: (1) The capability for doing so is available; (2) many sources must do so anyway for the purposes of obtaining permits, paying annual emission fees, and establishing applicability as a major source; and (3) therefore, the requirement will not entail new data collection and should not be burdensome. On the other hand, some commenters opposed having to speciate HAP's in averaged emission streams because: (1) Concentrations of some HAP's are often below detection limits; (2) small concentrations are difficult to measure accurately by many analytical techniques; and (3) it would be inordinately burdensome to identify all HAP's in wastewater considering the variability of wastewater streams. Thus, many of these commenters recommended setting a de minimis level below which a HAP would not have to be identified. The EPA recognizes that the HAP's in an emission stream must be identified to a certain extent in order to make the required demonstration of hazard or risk. The EPA also concurs that it may not be technically feasible to identify HAP's at levels below some minimal concentration. The concerns over HAP identification have been noted and will be considered in developing the technical support document for approving averages. 3. Limits on Averaging a. Number of points allowed in averages. The final rule limits a source to including no more than 20 Group 1 and Group 2 emission points in an emissions average. Where pollution prevention measures are used to control emission points to be included in an average, no more than 25 points can be included. For example, if two points to be included in an average are controlled by the use of a pollution prevention measure, the source can include up to 22 points in their emissions average. However, if 6 or more points in the average are controlled by pollution prevention, the source can include no more than 25 points in their average. In contrast, the proposed rule allowed for unlimited averaging. A number of commenters expressed concern over the difficulty and burden of overseeing averages of large numbers of points. Some commenters contended that the resources required to administer the rule with emissions averaging are much greater than for the rule without averaging and exceed what can be anticipated from part 70 permit fees. Because the complexity of averaging across a large number of points raised significant enforcement concerns, as well as concerns about the resource burden on implementing agencies, the supplemental notice solicited comment on limiting averages. A number of commenters responded to the supplemental notice in support of limiting the number of emission points, citing the same concerns as at proposal about the burden and cost of overseeing and enforcing large averages. In contrast, several commenters considered it inappropriate to limit averages, arguing that: (1) The design of the program already limits the number of points; and (2) Allowing unlimited averaging would not add much burden to implementing agencies because most of the burden of monitoring, recordkeeping, and reporting is borne by the source. Some commenters noted, and the EPA concurs, that most sources will not find a large number of opportunities to generate cost-effective credits. Hence, it can be anticipated that most averages will involve a limited number of emission points, and imposing a limit should not affect most sources. The EPA does not agree that the implementing agency would not bear much of the burden of averaging. The source's effort to comply with monitoring, recordkeeping, and reporting requirements will be matched equally by the implementing agency's oversight and approval. Some commenters suggested ways to limit averages other than on the basis of number or percent of points such as: (1) Selecting points to include or exclude on a case-by-case basis depending on characteristics of the proposed points and their emissions; (2) excluding wastewater; or (3) setting a mass limit for a source's emissions on the basis of allowable emissions. As explained in section V.D.1.b, ``Emission Points Allowed in Averages,'' of this notice, all emission points except for equipment leaks are considered appropriate for emissions averaging at any source subject to the rule. To limit their inclusion based on their characteristics under case-by-case decisions would add unreasonable complexity for both the source and the implementing agency. Also, as discussed in section V.D.1.b of this notice, the EPA maintains that wastewater emissions points should remain eligible for averaging. Finally, placing a mass limit on a source would be difficult to enforce and also add complexity to the rule. Several commenters considered the proposed range of 5 to 15 points or 5 to 15 percent of total points arbitrary and claimed there is no rational basis upon which to base a limit. One commenter advocated leaving selection of the number or percent limit to the discretion of the implementing agency. Otherwise, there was no consensus among commenters on whether the limit should be based on a number or a percent nor what value in the range was appropriate. The EPA rejected the choice of a fixed percentage of points at a source because for larger sources, this could result in hundreds of emission points in averages, which is unacceptable from an enforcement perspective. The limit of 20 points in an average, 25 points if pollution prevention measures are used, was chosen because the EPA anticipates that most sources will rarely want to include more than 20 points in an average. In addition, allowing much more than 20 points would make enforcement increasingly untenable. Thus, the competing interests of flexibility for sources and enforceability were balanced in this decision. A higher number of points is allowed where pollution prevention is used in order to encourage pollution prevention strategies, and because the same pollution prevention measure may reduce emissions from multiple points. b. State Discretion. The final rule grants State and local implementing agencies the discretion to preclude sources from using emissions averaging to comply with the HON without using the section 112(l) rule approval processes encoded in 40 CFR 63.92 through 63.94. Without this provision, if a State or local agency wished to receive delegation of authority to implement and enforce the HON without averaging, EPA review, according to the procedures in 40 CFR 63.92, would be required. Several commenters recommended that State and local agencies be allowed to exclude emissions averaging because: (1) Averaging may conflict with their own policies, such as State new source review and existing programs for controlling HAP's; and (2) the State or local agency may not have the resources to administer the rule, given the complexity added by the emissions averaging provisions. The EPA also recognized that because of statutory limitations, some States do not have the authority to elect requirements that are more stringent than Federal standards. States with these statutory limitations might not otherwise be able to use the rule approval processes [established in subpart E pursuant to section 112(l) of the Act] to remove emissions averaging as a compliance option for the HON. Because of these concerns stated at proposal, the supplemental notice solicited comment on the advisability of granting State or local agencies the discretion to not include emissions averaging in their implementation of the rule without having to go through the section 112(l) rule approval process. Several commenters responded in favor of the provision granting States more flexibility in excluding emissions averaging for the reasons stated in comments on the proposal and also because: (1) Some States are opposed to allowing emissions averaging due to concerns over its enforceability and its potential for allowing increased health risk compared to point-by-point compliance; and (2) it allows States greater flexibility in implementing the rule. At the same time, several commenters opposed the provision stating that: (1) States should not have the option of excluding emissions averaging since they do not have the option of excluding other provisions of the rule; (2) averaging does not add much or any administrative burden to States; and (3) if some States exclude averaging, an uneven ``playing field'' of different rules would be created, penalizing sources in States that do not allow averaging. The EPA maintains that States should have discretion on whether to allow emissions averaging for the following reasons. First, averaging increases the complexity of the rule and thus, increases the administrative burden on State and local agencies. This is an especially important concern because State and local agencies have limited personnel and resources. Second, the EPA understands that averaging conflicts with some existing State programs for regulating HAP's. Thirdly, because emissions averaging is an alternative compliance method to the primary control strategy, States should have the discretion to exclude it as opposed to other provisions that are essential to the rule and for which no alternative compliance mechanism has been provided. Even though the EPA supports the use of emissions averaging where it may be appropriate, its use must be balanced by the individual needs of States and local agencies that bear the responsibility for administering and enforcing the rule. Finally, this provision does not create an uneven ``playing field'' because without this provision, most States could exclude emissions averaging from their implementation of the HON through the section 112(l) rule adjustment process in 40 CFR 63.92. Including the provision in the HON will reduce paperwork burdens on States, expedite delegation of the rule to States, and remove a potential source of uncertainty for sources subject to the HON. The section 112(l) rule approval processes require States to make a demonstration that the State rule is of equivalent or greater stringency to the Federal rule. For a State rule without averaging, one component of this demonstration would be to show that the lack of averaging did not result in the State rule being less stringent than the Federal rule. The EPA has determined that requiring States to make this demonstration would be a needless exercise for the following reason. Today's rule defines both point-by-point compliance and averaging as acceptable ways of achieving a MACT level of control. If all sources in a State use the point-by-point compliance method--as would be the case in a State that implemented HON requirements without averaging--all sources would be achieving the MACT level of control required by today's rule. Under today's rule, no source is required to achieve emissions reductions greater than would be achieved by point- by-point compliance, and no source is required to use averaging. Therefore, a State rule that implements requirements of the HON rule without averaging is equivalent in stringency to the Federal HON rule. Based on this equivalency finding and today's rule, the EPA is allowing States to implement the HON unchanged without averaging through the same processes available to States that wish to implement the HON unchanged with averaging. Before a title V operating permit program is in effect in a State, the State may implement the HON without change through a streamlined procedure in the section 112(l) rule encoded as 40 CFR 63.91. After the State's operating permit program is in effect, the State may request delegation of the HON without change without going through the section 112(l) delegation processes. Also, based on today's equivalency finding and rule, a State seeking approval for a State rule that differs from the HON and also lacks averaging will not have to make a demonstration related to averaging as part of their equivalency demonstration to satisfy EPA review under 40 CFR 63.92, 63.93, or 63.94. Providing these clarifications at this time will benefit sources as well as States. Without the clarifications, sources might be uncertain during the section 112(l) approval process about whether averaging ultimately would be allowed or not, yet would be given no added time for compliance. The EPA predicts that because of their complex nature, many HON sources will need the full time period allowed for compliance. Two commenters objected to the EPA's proposal to provide in the rule itself that States would have the discretion to not include emissions averaging in their implementation of the HON without having to go through a section 112(l) rule approval process. One of the commenters asserted that this proposal would circumvent the mandates of State legislatures that had limited the ability of their environmental agencies to enact requirements more stringent than Federal requirements. The other commenter stated that this proposal was unnecessary because the section 112(l) rule provides ample flexibility and that the proposal would create difficulties for States since they would have to choose whether or not to adopt averaging. The EPA does not believe that either of these comments warrants departing from the supplemental proposal regarding this issue. First, by providing for State discretion to decide whether to implement the HON with or without averaging, the EPA is not circumventing any State laws or overriding the decisions of State legislatures that limit the ability of State environmental agencies to adopt requirements more stringent than Federal requirements. The EPA maintains that implementing the rule with averaging will achieve equivalent or better emissions reductions (in part due to the discounting provisions) than implementing the rule without averaging. Consequently, in the EPA's view, a decision to implement the rule without averaging would not be a decision to implement a more stringent program. Moreover, if a State law or constitution contained provisions that, in the State's view, prevented the State from adopting the rule without averaging, nothing in the rule would override that provision, i.e., in that situation, the State agency would not have the authority to implement the rule without averaging and the provision allowing the State to choose would not change that. Second, the EPA does not agree that providing for State discretion in the HON itself is either unnecessary or burdensome for States. Use of a section 112(l) rule approval process would also permit States to choose to implement the HON without averaging, providing for that choice in the HON itself streamlines the process by eliminating EPA review of the choice. In addition, since the section 112(l) rule permits States to make the choice, providing for the exercise of such discretion in the HON itself cannot be viewed as placing any new burdens on the States. Finally, the EPA maintains that the provision of an option will not impose a burden. The provision of an option increases choice and flexibility; it does not impose new requirements. c. Credit discount factors. A discount factor of 10 percent is required in calculating credits for emissions averages in the final rule. An exception is provided for reductions accomplished by the use of pollution prevention measures. For pollution prevention measures, full credit with no discounting is allowed. At proposal, the EPA sought comment on whether it is appropriate to require the use of a credit discount factor and what value between 0 to 20 percent should be selected for the discount factor. A number of commenters supported the use of a discount factor, contending that if the use of emissions averaging can enable sources to realize a cost savings, the environment should benefit from that cost savings as well. The EPA is persuaded that credit discounting is one way to provide such a benefit to the environment. A discount factor would reduce the value of credits in the emissions average by a certain percentage before the credits are compared to the debits. In considering a discount factor, the EPA examined the requirements for determining MACT in section 112(d) of the Act. Section 112(d)(2) specifies that MACT standards shall require the maximum degree of reduction in emissions of HAP's, taking into consideration, among other things, the cost of achieving those reductions. By defining the source broadly and including the option for emissions averaging in the final rule, it could be argued that the EPA is providing flexibility for source owners and operators that would lower the costs of compliance. The EPA is persuaded that, to carry out the mandate of section 112(d)(2), some portion of these cost savings should be shared with the environment by requiring sources using averaging to achieve more emission reductions than they would otherwise. Several commenters opposed the idea of a discount factor for a variety of reasons. Several warned that a discount factor would reduce and could completely eliminate the incentive to use emissions averaging and to develop innovative technologies which, in turn, could defeat the EPA's efforts to encourage flexible compliance and innovation. However, the EPA maintains that the discount factor is not large enough to provide such a disincentive. The value is consistent with those used in similar rules and programs. In addition, pollution prevention innovations are specifically exempted, which is discussed in the next paragraph. Other commenters viewed a discount factor as an inappropriate penalty or price for achieving cost savings through averaging, and some considered a discount factor to be inconsistent with the statutory intent that MACT be implemented in a flexible and cost-effective fashion. The EPA submits, however, that the emissions averaging program as a whole provides ample flexibility and opportunity for cost savings. Sources clearly have more flexibility to choose more cost-effective means of compliance through averaging than without it. A 10 percent discount on credits does not negate this. Credits generated through use of a pollution prevention measure need not be discounted, because the EPA recognizes that encouraging pollution prevention will result in more overall emission reductions, possibly including multimedia reductions and lower overall releases into the environment. For the purposes of the rule, the EPA is referring to any pollution prevention activities described in the Agency's Pollution Prevention Strategy (56 FR 7849) that are applicable to this industry. The following activities are included in the description of pollution prevention: (1) Substitution of feedstocks in making a product that reduces HAP emissions; (2) alterations to the production process to reduce the volume of materials released to the environment; (3) equipment modifications; (4) housekeeping measures; and (5) in-process recycling that returns waste materials directly to production as raw materials. Other pollution prevention approaches that are identified in the EPA's Pollution Prevention Strategy and are applicable to this industry are also acceptable for credit. 4. Implementation and Enforcement a. Compliance period. The EPA has decided to establish an annual compliance period for emissions averaging. The rule was originally proposed with an annual compliance period, and additional comment was solicited in the supplemental notice on four alternative bases for determining compliance: (1) A quarterly block averaging period; (2) A quarterly block averaging period with banking for up to one or two additional quarters; (3) A semiannual block averaging period with banking for an additional six-month period; and (4) A semiannual block averaging period. Several commenters supported an annual compliance averaging period at proposal and in response to the supplemental notice claiming: (1) It is necessary to accommodate realistic operating scenarios in which production rates naturally vary; (2) it is consistent with compliance periods for programs promulgated under title I and title IV of the Act; and (3) concerns about the enforceability of an annual period are unwarranted. At the same time, several commenters criticized the proposed annual period as: (1) Too long, especially compared to other regulatory programs; (2) an administrative burden and thus, an obstacle to effective enforcement; and (3) not protective of public health because an annual compliance period could allow peak exposures for short periods during the year. Some commenters recommended the quarterly block averaging period without banking as manageable, enforceable, and the best of the four proposed options in the supplemental notice. A few commenters supported quarterly averaging with banking. Other commenters supported semi- annual averaging with banking as a period that would ensure operational flexibility and reduce risk. No commenters recommended the semiannual period without banking. Some commenters contended that the compliance period should not be any longer than periods currently used in State programs. The final rule requires that the credits and debits generated in emissions averages balance on an annual basis, and that debits do not exceed credits by more than 30 percent in any one quarter of the year. These two requirements are used together to establish an emissions averaging system that provides flexibility for changes in production over time without allowing for wide-ranging fluctuations in HAP emissions over time. The annual compliance period was selected to provide sources considerable latitude in selecting points for inclusion in emissions averages. With an annual compliance period, sources can average emission points that may not have the same emission rates during some periods of the year, as long as they are similar on an annual basis. This latitude will also be useful to accommodate averages with points that must undergo temporary maintenance shutdowns at different times during the year. Nevertheless, the annual compliance period required here is solely meant to accommodate the specific circumstances of the HON, and is not intended in any way as establishing a precedent for future rulemakings. In selecting a compliance period for averaging, the EPA also considered the need to verify compliance and, when appropriate, take enforcement action in a timely fashion. One concern about an annual compliance period is that the EPA's authority to take administrative enforcement actions would be significantly reduced because section 113(d) of the Act limits assessment of administrative penalties to violations that occur no more than 12 months prior to the initiation of the administrative proceeding. Administrative proceedings are far less costly than judicial proceedings for both the EPA and the regulated community. The requirement that debits not exceed credits by more than 30 percent in any quarter enables the EPA to use this administrative enforcement authority by providing a shorter period in which to verify compliance. b. Quarterly emissions check. As noted previously, the final rule also includes a quarterly emissions check whereby debits cannot exceed credits by more than 30 percent. The emissions check was proposed as a limit on the percent by which debits could exceed credits in a quarter. Comment was requested on what the limit should be within a range of 25- 35 percent. The proposal preamble also presented another alternate quarterly limit suggested by industry which would structure the check as an absolute emissions limit. Several commenters who supported an annual compliance period concurred that a quarterly check was reasonable to allay concerns over high emissions in short periods. However, several commenters opposed the proposal contending that: (1) Debits should never be allowed to exceed credits in any time period; (2) 25 to 35 percent is still not protective of health and welfare; and (3) It would be difficult for inspectors to determine whether or not a facility is in compliance with its allowable emissions level. The EPA did not adopt the suggestions of these commenters because the emissions averaging program is intended to allow flexibility within the quarterly and annual limits. This flexibility would be too severely restricted if the suggestions, such as never allowing debits to exceed credits, were adopted. The quarterly check will protect against emission peaks so that health and welfare effects are avoided. The 30- percent differential between debits and credits should not result in a significant increase in emissions because only the emissions from the few points in the average would increase. The EPA maintains that these requirements are enforceable on a quarterly basis in that inspectors will be able to total the credits and debits and determine if the source is in compliance with the quarterly emissions checks and the annual balance of credits and debits. Some commenters supported the alternative industry proposal for a quarterly check because: (1) It avoids situations where an emission point is operated simply to generate needed credit; and (2) it allows for easier, more flexible planning because the source would know what its allowable emissions are for a fixed period. In contrast, one commenter opposed the alternative proposal claiming that the allowable emissions level would bear no relationship to the emissions level sought to be achieved. The EPA maintains that a system of assigning credits based on allowable emissions requires a great deal more scrutiny of the source's prediction of operating levels. Operating levels for allowable emissions are based on representative predictions of realistic operating scenarios, and such a system creates an incentive to ``game,'' i.e., to project higher utilization rates for credit-generating points than is representative or realistic. The EPA did not adopt the industry alternative for the quarterly emissions check because of concerns about an absolute emissions limit based on projections. However, the EPA did select the midpoint of the proposed range of the quarterly check as a way of balancing industry's concerns about operational flexibility with other commenters' concerns about protection from peak emissions. c. Banking. Credits cannot be banked for future use in emissions averaging. Provisions for banking were included in the proposed rule, and the EPA requested comment on whether or not allowing credit banking was appropriate. A number of commenters opposed allowing banking of emission credits for several reasons, including: (1) The requirement to achieve the maximum achievable emission reductions is violated when banked credits are used to offset debits; (2) Sources with banked credits will plan and operate less carefully; and (3) The use of banked credits will increase HAP exposures and create administrative difficulties. Several commenters supported allowing credit banking, claiming that it would: (1) Act as a safety valve for unexpected events and thus offer needed flexibility to sources and increase the likelihood of a successful averaging program; and (2) Encourage sources to install more stringent controls earlier to begin creating surplus credits to be banked. Banking of surplus credits was deleted from the final rule primarily due to the likelihood of significant administrative burden resulting from its use. The EPA believes that administration of the rule must be kept as simple as possible, and banking represented a complication that would have affected sources and implementing agencies alike. In addition, if banked credits were allowed to offset unexpected increases in emission debits, peak HAP exposures could be more likely, and in some years when banked credits would be used, sources could be emitting beyond the standard. The additional flexibility afforded sources through banking would have been offset by the increased administrative burden and potential for peak exposures such that little overall advantage could be gained from banking. d. Credits for previous actions. Credit is not allowed in the final rule for any previous actions, which, for the purposes of the rule, are defined as any control actions taken prior to the passage of the 1990 Amendments to the Act on November 15, 1990. This is in contrast to the proposal, which allowed three exceptions: (1) Pollution prevention measures taken after 1987 and qualifying under the EPA's Pollution Prevention Strategy; (2) 33/50 commitments; or (3) Early Reductions commitments other than equipment shutdowns. Control actions that meet the other requirements in the standard, and that were taken after November 15, 1990, such as actions taken as pollution prevention measures as part of the 33/50 program, can be used to generate credits for an averaging program. However, as outlined in the proposal, controls applied as part of an Early Reductions commitment can generate credits only if they are more stringent than HON requirements and only after the relevant point becomes subject to the rule, that is, after the expiration of the 6-year extension for the Early Reductions source. Several commenters generally opposed allowing emissions averaging credit for previous actions, and several specifically opposed the proposal to allow the three exceptions. The commenters stated various reasons for their opposition to allowing credits for previous actions including: (1) Participants in these programs had already derived sufficient regulatory, economic, and public relations benefits so that additional credit was unwarranted; (2) Reductions under the 33/50 and Early Reductions Programs do not constitute emission reductions under the HON; (3) The EPA would be granting credit for emission reductions that would have occurred anyway, possibly because of existing State or Federal requirements, and thus, these credits would be only ``paper credits,'' not new emission reductions; and (4) Such credits violate the maximum achievable reductions requirement. On the other hand, a number of commenters argued that emissions averaging credit should be allowed for all previous actions. The commenters argued, for instance, that: (1) Not allowing credit was unfair and penalized sources that installed controls early and that early actions should be rewarded instead; (2) it is a contradiction that a controlled emission point that meets the requirements of the rule can be in compliance no matter when it was controlled but is ineligible to generate credits for emissions averaging; and (3) if credit is not allowed, control devices already installed on Group 2 emission points will be removed and placed on Group 1 points. Many of these commenters considered other prior reductions to be appropriate as credit generators, such as: (1) any voluntary control measures; and (2) any verifiable control measures. The EPA agrees that emission reductions achieved prior to November 15, 1990 were accomplished for reasons unrelated to the Amendments or the rule and thus constitute part of the baseline control of a source. This rule does not allow actions taken before passage of the 1990 Amendments to be used to generate emission credits because such reductions would have occurred anyway, for reasons unrelated to the 1990 Amendments or the proposed rule. If the EPA allowed these actions to generate emission credits, then the source would be able to generate more emission debits and, thus, more total emissions. Emissions averaging is a method for complying with subpart G and should not result in more emissions than the other compliance options. With concern about the equivalency of emissions reductions from averaging and non-averaging in mind, the Administrator also imposed the limitation that controls applied to comply with a State or Federal rule or statute (other than the HON) cannot be used to generate emissions averaging credit. As with credits for controls applied before the HON baseline date, credits for controls applied to comply with another rule increase the source's ability to generate debits, but do not generate new emission reductions, thus creating more total emissions. At the suggestion of the public comment, the Administrator chose to disallow HON averaging credit for controls applied to comply with other requirements, thus ensuring that the source would not receive a ``windfall'' of credits. However, if an emission point has been used to generate emissions averaging credit in an approved emissions average, and the point is subsequently made subject to a State or Federal rule other than this subpart, the point can continue to generate emissions averaging credit for the purpose of complying with the previously approved average. This provision does not constrain a State's ability to establish any control requirements it believes are necessary for purposes of attaining the national ambient air quality standards or to reduce air toxic emissions. By including this provision in the final rule, the Administrator has taken yet another step to ensure that averaging provides equivalent or better air quality protection. Although the three exceptions to the 1990 baseline that were included in the proposal were deleted from the final rule, the EPA is committed to the success of the 33/50 and Early Reductions Programs and encourages the use of pollution prevention wherever feasible. This rule does not diminish that commitment. Reductions achieved after November 15, 1990 under the 33/50 and Early Reductions Programs or by the use of pollution prevention are fully creditable towards an averaging program. e. Questionable monitoring. In the final rule, when an emission point included in an average experiences an excursion, the presumption is that a sufficient malfunction has occurred such that no credits or maximum debits should be assigned to the point. As discussed in section V.E.2.b, ``Excused Excursions,'' of this notice, an excursion occurs when either: (1) There are insufficient monitoring data; or (2) the operating parameter values are outside the permitted range. The final rule provides that no credits and maximum debits will be assigned for excursions because any other assumption would result in emission reductions that could not be verified or adequately enforced. However, if the source has data indicating that some partial credits or debits may be warranted, it can submit that information to the implementing agency with their next Periodic Report. Thus, partial credits and debits can be assigned with the approval of the implementing agency. The proposed rule did not contain these provisions, but comment was requested in the supplemental notice on the advisability of including these provisions. A number of commenters supported the provisions to account for excursions because: (1) They create an incentive for sources to maintain and operate their monitoring equipment in good working order; and (2) other methods for estimating emissions are inadequate and should not be allowed as substitutes during these periods. On the other hand, several commenters considered the provisions too extreme, claiming that: (1) Even though excursions may occur, the control device may not have failed completely; and (2) the compliance provisions for points included in averages should not be more stringent than for the ones that are not included. The EPA maintains that these provisions are necessary to ensure that averaging achieves equivalent reductions to point-by-point compliance at all times. Emissions averaging depends on emissions estimates made beforehand and the demonstration that debits and credits balance made after the fact. Compliance on a point-by-point basis requires only that the source demonstrate that the RCT was operated at the proper design specifications. Hence, these provisions are not more stringent; rather, they are more detailed to ensure the consistency of the debit/credit estimation. The EPA agrees that there may be some cases or conditions under which the implementing agency can be satisfied that granting partial or full credits and debits is still warranted. Therefore, the final rule provides that the evaluation and issuance of credits and debits during questionable periods shall be at the discretion of the implementing agency. f. Reference Control Efficiencies. The final rule does not allow sources to get emissions averaging credit for the use of RCT above its designated reference efficiency rating. In contrast, the proposed rule provided two exceptions in which credit would be allowed for control above rated efficiencies: (1) Storage vessels controlled with closed vent systems and a 98-percent efficient control device, and (2) process vents on which the source had demonstrated to the EPA that control can achieve 99.9-percent reduction. These two exceptions have been deleted in the final rule. Several commenters supported allowing credit for the use of RCT at a more efficient level than its rated efficiency as long as more efficient control was demonstrable. Some commenters suggested that credit for potentially significant reductions would otherwise be lost. Other commenters warned that without such credit, sources would have no incentive to develop existing control technologies further to achieve greater efficiencies from RCT. At the same time, some commenters supported not allowing credit for RCT achieving higher efficiencies and opposed the two exceptions included in the proposal. One commenter argued that allowing credit for overcontrol is inappropriate because the rated efficiencies are intentionally conservative and understate the actual reductions the RCT would achieve if properly operated. As such, more credit would be allowed for overcontrol than is warranted. Some commenters stated that the use of fixed reference control efficiencies simplifies the averaging process by applying uniform credits and debits. Reference control efficiency ratings for RCT were established because each RCT has a minimum level of emissions reduction that can generally be achieved. The EPA acknowledges that RCT can sometimes achieve greater emission reductions. However, providing credits for these instances is inappropriate because the magnitude of debits, not just credits, is based on the RCT's reference efficiency ratings. If it could be determined that the RCT on a debit generator could achieve greater reductions than its rated efficiency, the magnitude of debits from the point would be greater. Thus, to give credit for reductions above an RCT's rated efficiency and not to increase the magnitude of debits as well would represent a windfall from averaging. g. Approval of New Devices. The procedures that were proposed for approving new devices for compliance purposes or as reference control technologies have been maintained in the final rule without change. Some commenters requested more guidance from the EPA on the process for approving innovative control technologies. Others were concerned with the time required to approve new technologies, including the time required to review for broader applicability. The EPA considers it necessary to be deliberate in approving new technologies especially when proven reference control technologies are available. The design and operation of new technologies are certain to be unfamiliar, so the rule provides for a 120-day period for the EPA or the permitting authority to determine whether sufficient information to determine a nominal efficiency has been submitted. Then, the EPA or the permitting authority must decide within an additional 120 days after sufficient information has been submitted whether to approve a new technology and what nominal efficiency to assign. Moreover, review of a new technology for broad applicability does not require any additional time beyond the time required for review and approval of the new technology. Where the EPA is responsible for approval, the approval and the review for broad applicability are one and the same. Where the permitting authority is responsible for approval, the rule provides that any further EPA review for broader applicability shall not delay the permitting authority's approval of the new technology for use in limited circumstances. E. Compliance, Recordkeeping, and Reporting 1. General Burden In the final rule, every effort has been made to reduce the recordkeeping and reporting burden of the HON. The EPA has streamlined the rule to include only the monitoring, recordkeeping, and reporting necessary to ensure compliance. Many commenters stated that the proposed monitoring, recordkeeping, and reporting requirements of the HON would be excessive and burdensome. The commenters contended that the requirements would be very costly, are unnecessary for assessing a source's compliance status, and provide no environmental benefit. The single most significant change made to reduce the burden is requiring retention of hourly average values of monitored parameters instead of 15-minute values. This change reduces by a factor of four the number of records that must be digitally converted by computer systems, copied onto tapes or printed as hard copy, duplicated, and stored. There are a number of other areas where the burden has been reduced in the final rule. For instance, the transfer operation provisions were revised to no longer require 5-minute records and to allow design analyses instead of performance testing for racks that are used infrequently (see section V.G.3.b of this notice, ``Transfer Operations--Testing and Monitoring''). Equipment leaks recordkeeping and reporting requirements have been reduced by streamlining the reporting system so there are two reports per year, which can be submitted at the same time as the subpart G reports. To reduce the leak detection burden, response factor adjustments to Method 21 results are not required in the final rule. The requirements to identify and document equipment not in VOHAP service and equipment in vacuum service have been deleted. (The rationale for these equipment leaks changes is contained in section VI.D and E of this notice.) Wastewater operations monitoring, recordkeeping, and reporting requirements have also been reduced. Method 21 is now only required initially, instead of annually as proposed, and visual inspections are performed on a semi-annual basis. Monthly measurements required in table 11 of the proposed subpart G were deleted because the initial performance test is sufficient to determine compliance. A change to the location of point of generation sampling will reduce the testing, monitoring, reporting, and recordkeeping requirements for some sources because sampling may be done at fewer locations. The compliance requirements for maintenance wastewater and maintenance turnaround wastewater have been combined, which simplifies compliance and reporting. Very small containers (less than 0.1 m\3\ capacity) are no longer subject to the rule, reducing the monitoring and recordkeeping burden. These and other changes to the wastewater provisions are discussed in sections V.C.3 and V.G.4 of this notice and in BID volume 2B. In addition, the final rule allows sources to request approval to use alternative monitoring and recordkeeping systems (in addition to being able to request approval to monitor alternative parameters as allowed in the proposed rule). This will reduce the burden by allowing greater use of existing systems. Alternative monitoring systems specifically discussed in the rule include non-automated systems and data compression systems. These systems will be allowed on a site- specific basis, dependent upon approval of the permit authority, as described in section V.E.2.c of this preamble. Some repetitive reporting has been eliminated. For example, new sources that submit an application for approval of construction do not need to submit an Initial Notification. Electronic submission of reports is also allowed, if acceptable to the permit authority. For further discussion, see chapters 2 and 3 of BID volume 2E and the following sections of this preamble. 2. Monitoring and Relationship to Compliance a. Continuous parameter monitoring and compliance determination. The final subpart G provisions, as did the proposed provisions, require monitoring of control device operating parameters and reporting of periods when parameter values are outside the site-specific ranges the source established in its operating permit or Notification of Compliance Status. Some commenters agreed with the HON approach to establish site- specific parameter ranges to indicate proper operating conditions, but many industry commenters asserted that parameter values outside the established range should not be considered a violation of the requirements for proper operation. These commenters requested the removal of provisions stating that parameter range excursions indicate the operator has failed to properly operate the control device. Several of these commenters requested that sources be able to demonstrate, through performance testing, that no violation of the emission standard has occurred. Several commenters stated that a direct correlation between the monitored parameter values and efficiency of the control device has not been established. Some environmental organizations and private citizens requested monitoring of the actual emission levels instead of monitoring whether the control equipment is operating properly. Several commenters discussed the difficulty of knowing whether an emission limit has been exceeded using parameter monitoring because excursions are initially violations of a permit condition and not a violation of an emission standard. The commenters were also concerned that emission standards may be difficult to enforce using this system. Several commenters requested clarification of the interaction of the Title VII Enhanced Monitoring program and HON and asked whether enhanced monitoring has been incorporated in the HON rule. The part 64 enhanced monitoring rule does not apply to sources subject to 40 CFR part 63, and therefore does not apply to sources subject to the HON. However, rules developed under section 112 of the Clean Air Act will include monitoring strategies that incorporate the concepts of enhanced monitoring established in section 114(a)(3) of the Act. This approach is designed to ensure that monitoring procedures developed for section 112 standards provide data that can be used as a determinant of compliance with each applicable standard, including emission standards. For rules where CEM's are not technologically or economically feasible, the EPA will generally establish operating parameters which must be continuously monitored to determine a source's compliance status. In order to determine compliance, parameters must be monitored frequently enough to allow the source owner or operator to certify whether compliance was continuous or intermittent for each recordkeeping period associated with the applicable emission limitation or standard. Generally, the EPA will select the parameters that must be monitored; however, the sources will establish, through performance tests, engineering analysis, and manufacturer's recommendations, the levels which must be maintained in order to remain in compliance with the emission standard. These source-specific levels will be incorporated in a source's operating permit (or, in the absence of an operating permit, these established levels will be directly enforceable) and will be used to determine a source's compliance status. For future section 112 standards, deviations from the operating parameters are expected to be considered violations of the applicable emission standard. However, in developing an operating parameter monitoring strategy for the HON, it became evident that the complexity of this particular standard, the wide range of processes and pollutants covered, and the potentially large numbers of emission points located at any one facility, would warrant a somewhat different approach in determining compliance based on monitored parameters. Specifically, when a daily average value of a monitored parameter is outside the established range, such an excursion would not be considered a violation of the emission standard, but rather, a violation of proper operating conditions. Further, the HON allows for a designated number of excused excursions, i.e., a predetermined number of average daily parameter values outside the source's established range, that would not constitute an operating parameter violation. This variation to the Agency's standard approach of incorporating enhanced monitoring concepts into section 112 rules does not signal a change in underlying Agency policy, nor should it be viewed as a precedent for future standards developed under 40 CFR part 63. Rather, the method of compliance determination in the HON represents an exception to the normal enhanced monitoring requirements, and one that is deemed necessary because of the diversity of emission points and the unique nature of the facilities regulated under this standard. The EPA believes that for other MACT standards which will regulate a more narrow range of industrial sources, a more precise link between operating requirements and emission violations will be justified. Many commenters requested that CEM's be included in the rule for use in monitoring HAP emission levels, instead of using continuous parameter monitoring. The EPA considered CEM's for use in the HON, but found them to be technically infeasible due to the lack of CEM technology for all 112 HAP's regulated by the HON. This determination is discussed further in section 3.2.4 of BID volume 2E. b. Excused excursions. The final provisions allow a maximum of six excused excursions for the first semiannual reporting period, decreasing by one excursion each semiannual reporting period, down to one excused excursion per period by the end of 3 years. Thereafter, sources are allowed one excused excursion per semiannual reporting period. Excused excursions are not considered violations. The EPA requested comment in the proposal preamble on the number of days or percent of operating time that should be allowed as excused excursions, and whether the excused number of days should decrease over time. A range of 3 to 6 days was proposed. Commenters supported a range of 0 to 6 days of excused excursions. A number of commenters stated that the excused excursions were necessary to account for inevitable and unanticipated operating parameter fluctuations. The system of decreasing the number of excused excursions as the source becomes more familiar with the operation of their control device allows sources to benefit from the knowledge they gain over time. The final rule states, as at proposal, that a malfunction that is included in the source's start-up, shutdown, and malfunction plan, required in Sec. 63.6(e)(3) of the General Provisions, is not considered an excursion if the plan is followed. If the plan is not followed, or if the malfunction is not included in the plan, this is considered an excursion. For the final rule, an excursion has occurred when the source's daily average falls outside the established ranges, or when monitoring data are insufficient to calculate valid hourly averages for at least 75 percent of the operating hours in a day. Monitoring data are insufficient to calculate a valid hourly average if measured values are unavailable for any of the 15-minute periods within the hour. If the excursion is not an excused excursion, it is a violation of the operating permit conditions (i.e., a violation of proper operation and maintenance of the control device). Each excursion is a direct violation of the operating conditions, but not the emission limit. As a violation of the operating conditions, the regulatory authority can take enforcement actions against the source. If the regulatory authority requests a performance test to determine compliance with the emission limit, and the test reveals the emission limit is exceeded, then the source has violated the emission limit and is subject to enforcement actions for violating the emission standard. c. Alternative monitoring and recordkeeping. The proposed provisions allowing sources to request approval to monitor alternative parameters were retained in the final provisions and expanded to allow sources to request approval to use alternative monitoring and recordkeeping systems. These monitoring systems would be approved by the permit authority on a case-by-case basis, and would include requests to use non-automated monitoring and recording systems and data compression systems. Many commenters requested that the rule allow the utilization of existing monitoring and recordkeeping equipment to the maximum extent possible, and discussed the need for these alternative monitoring and recordkeeping systems. A few commenters requested that sources that do not have automated monitoring and recording systems be allowed to continue to use manual recording systems and be granted a less frequent monitoring schedule. The EPA expects that there will be few facilities that would choose not to use automated recording systems (e.g., strip charts or computer systems) in light of the labor costs of manual recordkeeping. However, there may be specific cases where use of a manual system would be less burdensome, for example, a smaller, older facility that does not have computerized recording and already has a manual monitoring and recordkeeping system. Provisions were added to the final rule to allow sources with non-automated systems to request approval from the permitting authority to manually read the value of the relevant operating parameter less frequently than every 15 minutes. The rule provides specific criteria for such requests to ensure that the monitoring and recordkeeping system is sufficient to determine compliance. In particular, the system shall include manual reading and recording of operating parameter values no less frequently than once per hour and daily average values calculated from the hourly values. The request shall contain a description of the monitoring and recordkeeping system, documentation that the source does not have an automated system, reasons the source is requesting an alternative system, and demonstration that the monitoring frequency is sufficient to represent control device operating conditions. Approval of such systems will be decided on a case-by-case basis by the permit authority. Many commenters requested that data compression be allowed in order to allow use of current systems, while still allowing determination of when exceedances have occurred. Data compression systems do not record monitored operating parameter values at a set frequency, but record all values that meet set criteria for variation from previously recorded values. The commenters stated that they currently used data compression systems or intended to install such systems, and that the advantages of data compression include the ability to more accurately represent operating parameter variation, the ease of data retrieval from archived data, reduced data storage requirements resulting in reduced computer costs, automatic record generation, the ability to quickly detect operating problems, and access past data and predict future problems. The commenters provided technical information on data compression systems. After considering technical information on data compression systems, the EPA concluded that properly designed data compression systems can provide sufficient information for determining compliance. The final rule allows a source to request approval from the permitting authority to use data compression as an alternative monitoring and recordkeeping system. The EPA has established minimum criteria for using data compression, including: Measuring the operating parameter value at least once every 15 minutes; recording at least four representative values each hour; recording the date and time when monitors are turned off and on; recognizing unchanging data, alerting the operator, and recording the incident; and computing daily averages from the recorded data. At the end of the operating day, if the daily average value is not an excursion, the data may be converted to hourly averages instead of retaining the four individual data values for each hour. Approval of such systems will be decided on a case-by-case basis. Some commenters requested that sources be allowed to use interlock devices which monitor the control device operating parameters and shut down the process before an excursion can occur. The commenters suggested that if such systems are used, recordkeeping is not necessary. While the EPA wishes to encourage innovative technologies such as interlock systems, the EPA has insufficient information on the variety of designs and applications of interlock systems to specify alternative recordkeeping procedures that would be appropriate for all such systems. Sources wishing to use other alternative monitoring methods, including sources using interlock devices, may apply to do so according to the process described in the General Provisions Sec. 63.8(f). d. Inspections and non-continuous monitoring. For some emission points, such as storage vessels and some wastewater operations, continuous parameter monitoring is not feasible in certain circumstances due to the design of the control device or other operational and system design characteristics of the emission points or control technologies. One example of non-continuous monitoring is the periodic visual inspection of storage vessels equipped with internal or external floating roofs. If a failure, such as a gap or tear in the seal, is detected, the vessel must be repaired or emptied within 45 days. In addition, two 30-day extensions may be requested from the Administrator. Violations occur only when a failure is detected and the vessel is not repaired or emptied within 45 days or the time provided with an extension. More information on inspections and non-continuous monitoring is provided in chapter 6 of BID volume 2B for wastewater operations and chapter 3 of BID volume 2A for storage vessels. 3. Records a. Continuous records. The final rule allows retention of hourly average values of monitored parameters instead of 15-minute values for operating days when there is not an excursion. If there is a monitoring parameter excursion, the 15-minute values for the excursion period must be retained. A number of commenters requested that only hourly or daily averages be required, as 15-minute values would require reprogramming their computer systems and would be costly. The commenters also contend that 15-minute values may not be necessary to demonstrate compliance with the rule because operational problems would occur over a period of several hours, and could be discovered through the hourly averages. Some commenters suggested that 15-minute records should only be kept for days when there are parameter excursions. The EPA agrees with the commenters who suggested that hourly average values are generally sufficient to determine compliance, and that 15-minute records should be kept only if there is an excursion. As at proposal, compliance with the operating conditions is based on the daily average value of continuously monitored parameters. If the daily average value is outside the established range, this is an ``excursion.'' The proposal required retention of 15-minute average data values to substantiate the daily average calculations and provide a record of trends in control device operation over a shorter time period. Records of hourly average values are sufficient to accomplish these purposes, and will greatly reduce the recordkeeping burden of the HON. This change will reduce by a factor of four the number of records that must be digitally converted by computer systems, copied onto tapes and/or printed as hard copy, duplicated, and stored. It will avoid the cost of reprogramming existing computerized recordkeeping systems that commenters said are currently programmed to retain hourly averages. The reduction in the number of records will also simplify review of these records by enforcement agencies. The reduction in the number of records will not impair the ability to detect parameter excursions. The final rule requires continuous monitors to measure parameter values at least once every 15 minutes, as did the proposal, and many monitors are designed to measure more frequently. The final rule also requires recording of 15-minute average values or instantaneous readings taken at least once every 15 minutes. However, the final rule allows the 15-minute values to be converted to hourly average values at the end of the operating day if there was not an excursion. The 15-minute values can then be discarded, and only the hourly averages must be retained. For operating days when there is an excursion, the final rule requires retention of the 15-minute values of parameters. This will provide a more detailed record of those periods when there are problems. Keeping 15-minute instead of hourly values for excursion periods will not significantly increase the recordkeeping burden because there should only be a couple of days per year when there are parameter excursions for any given emission point. A few commenters stated that the requirement in the transfer operations provisions to take 5 [and 15] minute values was incompatible with their current data collection system, would be extremely costly, burdensome, and of no environmental benefit. The transfer provisions have been revised for the final rule and no longer require retention of 5-minute and 15-minute records. Hourly records (and 15-minute records for excursions) are required for transfer as well as the other kinds of emission points. Transfer is discussed in more detail in section V.G.3.b and in the BID. b. Accessibility/storage. A number of commenters requested that sources have the option of storing records at an accessible off-site location because retaining records on-site at a source for 5 years would be burdensome and expensive. This is an issue addressed in the notice presenting the final General Provisions to part 63. The provisions of subpart F are consistent with the final General Provisions. For the first 2 years, records may be retained on-site or at a central location accessible by computer. For the following 3 years, records may be maintained at an off-site location. c. Retention time. Several commenters maintained that retaining records for 5 years as required in the proposal would be burdensome and expensive. Instead, commenters suggested records be retained for 1 or 2 years. The final rule requires retention of records for 5 years. This is consistent with the General Provisions and the operating permits rule. This issue is addressed in the notice presenting the final General Provisions to part 63. The Agency's rationale is contained in the preamble to the final General Provisions. 4. Compliance Schedule a. Group status changes. The final rule establishes compliance dates for cases in which a Group 2 emission point becomes a Group 1 emission point. The final provisions differ from the proposed provisions. Several commenters requested that a Group 2 emission point that becomes a Group 1 emission point be granted 3 years to come into compliance, as existing sources are allowed 3 years, and the proposed 150-day period may not be possible given the time needed for permitting and installation of controls. The EPA decided that, in some cases, the proposed 150 days may not be sufficient to engineer, permit, purchase, and construct control equipment to comply with the requirements; whereas, in other cases, compliance could be achieved sooner. Therefore, the proposed 150 day period was deleted from the rule, and compliance date provisions were added to Sec. 63.100 of subpart F. In certain cases specified in subpart F, the source is allowed to establish a site-specific schedule subject to the approval of their permit authority. To be consistent with section 112 of the Act, the schedule can be no longer than 3 years. The reader should refer to Sec. 63.100 of subpart F to determine whether a site-specific schedule is allowed in a particular case. b. Compliance extensions. The final rule, like the proposed rule, states that requests for extensions must be submitted as part of the operating permit application or as part of the Initial Notification or as a separate submittal no later than the date the Implementation Plan is due. In the preamble to the proposed HON rule, the EPA requested comment on the potential difficulties of complying with the HON in the 3-year compliance time and through use of the 1-year request for a compliance extension. Many commenters stated that it would be difficult or impossible for some sources to meet the HON's 3-year compliance date due to both obvious and unforeseen circumstances and that the need for a compliance extension may not be recognized until after the Implementation Plan is due. The sources requested that they be allowed to apply for a compliance extension up until the compliance date. The issue of whether compliance extensions can be requested up until the compliance date is an issue with broad applicability to all part 63 standards and was raised in the public comments on the General Provisions to part 63. The HON is consistent with the final General Provisions. 5. Other Comments Many other comments were received on topics such as the five report system, electronic submittal of reports, recordkeeping and reporting consistency with other requirements, burden cost estimates, data collection and recording frequency, current use of automated and non- automated monitoring systems, record retention time and accessibility, impacts on regulatory agencies, site-specific ranges, performance testing, enforcement, and many other topics. A complete summary of the comments received and the EPA responses pertaining to monitoring, recordkeeping, reporting, and compliance may be found in chapters 2 and 3 of BID volume 2E. Comments and requirements pertaining to emissions averaging monitoring, recordkeeping, and reporting issues are discussed in section V.D of this notice and in section 2.8.2 of BID volume 2C. F. Coordination with Other Clean Air Act Requirements 1. General Provisions After proposal of the General Provisions (August 11, 1993; 58 FR 42760), the HON public comment period was reopened to take comment on several issues, one of which was the overlap between the HON and the General Provisions. Written comments were received from approximately 75 commenters. Many of these commenters contended that it was difficult to determine those instances when the General Provisions requirements apply to the HON. The commenters suggested that the HON specifically state those General Provisions sections that apply to the HON, instead of the current system which states which General Provisions sections do not apply. The commenters, some of whom also included the comments they had submitted to the General Provisions docket, provided tables and suggested text changes showing which specific General Provisions sections they thought were relevant to the HON, and which General Provisions sections they thought should not apply to HON sources. In response to these comments, the EPA has provided a table in subpart F of the rule which specifies which General Provisions sections do and do not apply to the HON. 2. Overlap with NSPS, NESHAP, and CTG For the final rule, the EPA has clarified which requirements are to be met when an emission point is subject to other air regulations in addition to the HON. The EPA agreed with commenters that the proposed rule did not provide adequate guidance regarding what to do when the HON overlaps with other NESHAP and NSPS. Several commenters contended that the proposed HON would lead to overlap with existing regulations, and because EPA did not provide details on which requirements are to be met when such situations occur, the overlap between the HON and other regulations would lead to confusion, inconsistent application of the requirements, and possible compliance violations. The commenters claimed that the EPA's direction to comply with the most stringent regulation was inadequate. Several commenters specifically questioned whether the language on overlapping requirements was intended for all facets of the HON or only for recordkeeping and reporting, since the requirement appeared in the recordkeeping and reporting section of subpart F. A number of commenters specifically stated that sources complying with the Benzene NESHAP or the Vinyl Chloride NESHAP should be exempt from complying with the HON because these standards are more stringent than the HON. A few commenters expressed concern that the wastewater provisions in the HON may conflict with the requirements of the Benzene NESHAP, particularly the use of biological oxidation units. The EPA recognizes that the guidance in the proposed HON on determining which requirements to comply with when regulations overlap was confusing. In order to clarify these requirements, the EPA has listed in Sec. 63.110 of the final rule which provisions owners or operators are required to comply with when they are subject to existing regulations. The EPA believes that in most cases the HON contains more stringent requirements than in other existing regulations. For these cases, the EPA has decided to override the requirements of the existing regulations with the requirements of the HON. In other cases, the owner or operator must either comply with the HON and the overlapping regulation, with the overlapping regulation, or some combination of the two. For most Group 1 emission points that are also subject to existing NSPS and NESHAP, the owner or operator is required to comply with the HON requirements. For wastewater, Group 1 and Group 2 streams must either comply with both the HON and the Vinyl Chloride NESHAP or submit a demonstration that compliance with the Vinyl Chloride NESHAP assures compliance with the HON. Group 1 and Group 2 wastewater streams subject to both the HON and the Benzene NESHAP must comply with both rules because it is not possible for one rule to override the other. The benzene rule cannot override the HON because the HON covers 112 organic HAP's whereas the benzene waste operations NESHAP only covers emissions of benzene. The EPA does not believe that in all cases demonstration of control of benzene will also demonstrate compliance with control requirements for all HAP's. The HON cannot override the benzene rule because the benzene rule applies to waste and wastewater and the HON only applies to wastewater. Thus, in the final HON, the EPA is requiring that a source subject to both rules must comply with both rules. For Group 2 emission points that are also subject to existing NSPS and NESHAP, Sec. 63.110 specifies which provisions of HON and which provisions of the other rules will apply. The EPA developed the specifications through a comparison of the rules and their monitoring, recordkeeping, and reporting requirements for each kind of emission point. When HON wastewater provisions overlap with RCRA regulations, the EPA has decided to allow owners or operators to either comply with the regulation they consider the most stringent, or to request a case- by-case determination by the Administrator of which requirements to comply with. A few commenters expressed concern that if future MACT standards require more stringent control, facilities would have to replace technology required by one standard with that required by another. The EPA's plan for implementing the Act is for each source category to have its own MACT standard. No two MACT standards should be applicable to the same emission point. The only future requirements that should apply to the emission points subject to the HON are those developed during the residual risk analysis for the HON. The EPA has done its best to clarify the applicability of the HON. However, it is difficult to anticipate all the potential overlaps with MACT standards that have not yet been drafted. In developing the applicability provisions of future MACT standards, the EPA will be as clear as possible and will avoid applying more than one MACT standard to the same emission point. 3. PSD/NSR For the final rule, the EPA maintains that the approach for estimating secondary impacts that was presented in the proposed HON is sufficient for rulemaking purposes. Several commenters argued that compliance with the RCT requirements of the HON would increase NOx and CO emissions, thereby requiring PSD or NSR determination depending on non- attainment status of the source. The commenters also contended that PSD and NSR determination would require a BACT or LAER analysis, air emissions modeling, offsets for NOx emission increases, and possibly a Federal Land Manager review. Several of the commenters claimed that the cost of these analyses and the control technologies they may require were not included in the cost analysis for the HON. The commenters contended that such costs would make compliance with the HON unaffordable. The commenters are correct that costs for controlling secondary impacts were not analyzed in the HON. However, the EPA did analyze the extent of multimedia impacts of applying the RCT's. The results of the analysis indicated that controls on process vents would result in only 6 percent of the sources exceeding the PSD NOx threshold of 40 tpy in non-attainment areas if combustion controls were applied, and none of the sources would exceed the CO emissions threshold of 100 tpy. None of the sources were determined to exceed the CO and NOx emission levels as a result of controlling transfer operations. Based on these results and the great flexibility provided in compliance options, the EPA does not consider that control of secondary impacts of applying the RCT's will significantly impact the cost of the HON. In addition, although the HON provisions for process vents and transfer operations require 98-percent control, they do not necessarily require combustion. A facility has the choice of applying the RCT or using any technology that achieves an equivalent emissions reduction. The process vents provisions also provide the option of modifying the process or using additional product recovery to raise the TRE to greater than 1.0, thereby converting the vent to a Group 2 vent. Other commenters argued that the permit review process for PSD and NSR would increase the amount of time for complying with the HON, and cause some sources to miss compliance dates. The EPA considers PSD and NSR concerns to be best handled on a site-specific basis. An individual source may cite the delays involved with obtaining PSD or NSR permits in requesting extensions from the EPA. Under the Pollution Control Project exclusion section of the NSR regulations, States will also have the flexibility to consider overall environmental benefits of pollution control and may not require a source to obtain preconstruction permits under PSD or NSR. Several commenters requested that EPA exclude from the definition of modification, and thus from NSR requirements, the installation of controls required in the HON that are considered environmentally beneficial. The EPA is reviewing possible changes to the NSR/PSD program. Until such changes are made, the EPA has decided that sources requesting exemptions will be handled on a case-by-case basis. Where a source merits it, the EPA will consider exclusions from some NSR/PSD requirements. 4. Section 112(g) Several commenters requested that the EPA clarify the relationship between the HON and requirements in section 112(g) of the Act. Some commenters requested that EPA provide definitions for modification and reconstruction as they apply to the HON. One commenter requested that the EPA incorporate a de minimis emissions increase concept for minor modifications. Case-by-case MACT emission limitations under the proposed section 112(g) rule do not apply to SOCMI sources covered by today's rule. The EPA need not add a de minimis emissions increase concept for the HON because the HON has established procedures for determining which operational changes require control and what level of control must be applied when an operational change occurs. In addition, since section 112(a) of the Act provides a definition for modification and Sec. 63.2 of the General Provisions (subpart A of 40 CFR part 63) provides a definition for reconstruction, these definitions need not be added to the HON. Sources subject to the HON are required to use the definitions in the Act and General Provisions, unless that part of the General Provisions is specifically overridden in the HON. Sources subject to the HON should note that subparts F and G establish administrative procedures to cover a variety of operational changes that are likely to occur at SOCMI facilities. These procedures specify the notification and approval requirements for each type of change. As stated in the preamble to the proposed rule implementing section 112(j) of the Act, it is the EPA's intent that the control requirements of individual MACT standards established under section 112(d) or 112(j) of the Act should supersede the control requirements of the section 112(g) rule. The proposed rule for section 112(j) was published in the Federal Register at 58 FR 37777 (July 13, 1993). In addition, as stated in the proposed rule implementing section 112(g) of the Act, it is the EPA's intent that the administrative procedures of individual MACT standards established under section 112(d) or the Act will supersede the administrative procedures of the section 112(g) rule to the extent that the administrative procedures of a section 112(d) rule satisfy the requirements of section 112(g) of the Act. [As proposed (58 FR 37778), standards established under section 112(j) of the Act would rely on the administrative procedures in the section 112(g) rule.] The question of whether MACT standard administrative procedures, such as those in the HON, supersede the administrative procedures of the section 112(g) rule is one on which comment is being requested in the section 112(g) rulemaking. Consequently, the application of section 112(g) administrative procedures to HON sources will not be finally resolved until the promulgation of the section 112(g) rule. Until final action on the section 112(g) rule, sources subject to the HON should follow the administrative procedures in subparts F and G, and, as appropriate, the General Provisions of 40 CFR part 63 subpart A, and the title V operating permits rule. One commenter requested that the EPA clarify whether emission points that are not regulated by the HON, but are part of the same plant site, would be considered area sources and what emissions would be available for offsets under section 112(g). The Act defines both major source and area source. If a plant site meets the definition of major source, it will be regulated as a major source under any applicable MACT standard. Plant sites that do not meet the definition of major source are considered area sources and could be covered under emission standards that regulate area sources. For example, if within a petroleum refinery that is a major source plant site, there are emission points associated with SOCMI processes, the SOCMI emission points would be regulated under the HON, whether or not they alone would constitute a major source. The refinery emission points would be regulated under the refinery MACT standard. The rule implementing case-by-case MACT emission limitations under section 112(g) will address sources that are not covered by a promulgated MACT standard. Only emission points that are not subject to a promulgated MACT standard could be available for offsets. If a source is regulated by a promulgated MACT standard such as the HON, the controls applied to comply with the promulgated MACT will not be available for offsets under section 112(g), as proposed. At plant sites with sources subject to the equipment leak provisions in subparts I and H, only the equipment leaks are covered by the HON. Thus, the section 112(g) control requirements could apply to the other actions and equipment at the plant site. 5. Residual Risk A number of commenters expressed concern with calculating residual risk on a plant-wide basis because once a MACT standard is promulgated for one source category within a facility, residual risk requirements could be triggered before other MACT standards are established for other source categories at the facility. In contrast, one commenter asserted that the legislative history of the Act requires that residual risk be calculated on a plant-wide basis. A number of other commenters expressed concerns with calculating residual risk on a source category basis because public health could be compromised if emissions were artificially split up for purposes of risk assessment, rather than considered as a whole. However, two commenters contended that implementation would be simplified if a source category approach were taken. Several other commenters argued that the basis for estimating residual risk should not be addressed in the HON or at this time. The commenters contended that Congress intended to defer risk-based standards until better methods of risk analysis have been defined. Some commenters requested that the EPA begin to investigate the appropriate methodology for determining residual risk. As many of the commenters have noted, residual risk will be determined at a later time. The EPA's intent in requesting comments on residual risk was to facilitate ideas on how residual risk should be analyzed. 6. RCRA and OW Regulations Several commenters asserted that the HON did not consider overlaps with RCRA rules. The EPA disagrees with the commenter's assertion that the EPA has not considered the implications associated with regulatory overlap between the HON and the RCRA regulations. In fact, the EPA has made every effort to identify areas in which these regulatory programs may overlap. The commenter did not express any particular concerns about specific areas of overlap. The EPA has identified several potential areas in which both the RCRA and the HON could apply to the same situation. To avoid dually regulating these areas, the EPA has tried to make the regulatory language in the HON consistent with existing RCRA requirements and, where appropriate, has designated which regulations the owner or operator must comply with to satisfy the requirements of both regulatory programs. For example, in the provisions that specify the required treatment processes for managing wastewater at SOCMI sources, the EPA will accept demonstration of compliance with RCRA requirements as demonstration of compliance with the HON for the following treatment processes: (1) hazardous waste incinerator permitted under 40 CFR part 270; (2) boilers and industrial furnaces either permitted under 40 CFR part 270 or certified as an interim status facility in compliance with 40 CFR part 266; and (3) underground injection wells permitted under 40 CFR part 207 and in compliance with 40 CFR part 122. These treatment processes are not subject to the treatment process requirements in the HON because the EPA recognizes that such treatment processes are already strictly regulated under the RCRA program. However, emissions from the wastewater stream must still be suppressed up to these treatment processes according to Secs. 63.133 through 63.137 of the HON. 7. Pollution Prevention For the final rule, the EPA maintains that the proposed HON sufficiently promotes pollution prevention for the various chemical manufacturing process units in the SOCMI. One commenter did not consider the HON to meet the requirements of the Act because it does not consider pollution prevention activities. Several other commenters contended that the HON discourages pollution prevention activities because it promotes use of pollution controls and safety measures instead of redesign of processes or material substitutions to eliminate emissions. Some of the commenters believed that industry will innovate and apply pollution prevention only if EPA forces them to do so. Many of the commenters recommended that the EPA revise the HON to encourage more pollution prevention. The commenters suggested that EPA: (1) Incorporate pollution prevention approaches in existing State programs; (2) Set a timetable for the elimination of emissions; and (3) Require evaluation of process and product changes prior to end- of-pipe controls. Pollution prevention activities, particularly process redesign, are site-specific. Therefore, it would not be practical or possible to stipulate specific requirements for the large number of chemical production processes subject to the HON. The EPA also considers that elimination of pollution through material substitution will not be possible in all cases because SOCMI products (many of which are listed as HAP's in section 112 of the Act) cannot be eliminated from use without adverse economic impact. Specifically, because the products of the SOCMI are used in the production of polymers, resins, pesticides, pharmaceuticals, etc., elimination of a SOCMI product would affect not only the SOCMI producer but also the downstream user of that SOCMI product. Many of the end-use products (e.g., resins, pharmaceuticals, etc.) could not be made from other materials. Thus, the EPA maintains that material substitution is better left determined by the marketplace rather than by mandate through a specific Federal requirement. The EPA believes that the HON sufficiently encourages pollution prevention. For example, within the provisions for process vents, storage vessels, transfer operations, and wastewater collection and treatment operations, there are compliance options that only specify a percent reduction of HAP emissions. To comply with most of these options, a source may use any means, including process changes or recovery devices, to reduce emissions by the specified percent. While process vent provisions do not allow use of recovery devices to achieve the 98-percent reduction, the process vents provisions encourage the use of process changes and recovery devices by including an option for achieving a specified TRE value instead of adding control. Thus, the owner or operator does not have to combust emissions to comply with the standards. The storage vessel provisions encourage the use of floating roofs to control emissions. Many of the requirements in the equipment leaks and wastewater provisions also encourage pollution prevention options to control emissions. The emissions averaging provisions encourage pollution prevention by: (1) Not applying a discount factor to credits generated by pollution prevention measures and (2) allowing an additional five emission points to be included in an average if pollution prevention measures are used. G. Miscellaneous Technical Comments 1. Process Vents a. Monitoring for Group 2 vents with TRE between 1 and 4. For the final rule, the EPA maintains the same position as at proposal for monitoring for process vents with a TRE between 1 and 4. Several commenters recommended that the same monitoring provisions for vents with a TRE between 1 and 4 be applied to vents with a TRE greater than 4 due to process fluctuations. Several other commenters requested that monitoring requirements for vent streams with a TRE between 1 and 4 be reduced or eliminated because of the burden without emissions reduction. The rule requires monitoring, recordkeeping, and reporting requirements for Group 2 vent streams with TRE index values between 1 and 4 to ensure those vents do not become Group 1 vents due to process or recovery device operating variations and remain uncontrolled. Group 2 vents with TRE index values greater than 4 are not required to monitor. An analysis was performed prior to proposal that shows that a vent with TRE greater than 4 is unlikely to become Group 1 due to process or recovery device operating fluctuations or measurement uncertainties, whereas if TRE is greater than 4, it is important to monitor recovery device operating parameters, because variations in process or recovery device operations could cause such streams to become Group 1. The EPA recognizes the uncertainty present in TRE calculations, but decided that a sufficiently large safety factor has been included for vents with a TRE greater than 4. The decision not to require monitoring for process vents with a TRE greater than 4 reduces the burden of regulation for both the industry and regulatory agencies. b. Product accumulator vessels. For the final rule, the EPA has deleted the term ``product accumulator vessel,'' and will regulate equipment previously described as product accumulator vessels as follows: (1) Vents from distillate receivers and product separators will be regulated as process vents under subpart G; (2) hot wells will be regulated by the wastewater provisions under subpart G; and (3) surge control vessels and bottoms receivers will remain in subpart H. The definition of process vent has been revised to include distillate receivers and product separators. Several commenters expressed concern due to the inconsistencies in the proposed provisions for product accumulator vessels. The major concerns included: (1) Multiple standards (process vents under subpart G and equipment leaks under subpart H) would apply to the same vent; (2) there are different compliance dates in subparts G and H; (3) the proposed definition did not distinguish between product accumulator vessels and storage vessels or other in-process vessels; and (4) product accumulator vessels, which are point sources, would be regulated under provisions that were intended for fugitive emissions (i.e., equipment leaks). The commenters suggested eliminating the inconsistencies by: (1) Deleting the subpart H requirements for product accumulator vessels and regulating them as process vents under subpart G; (2) allowing sources to select whether to comply with the requirements of subpart G or subpart H; or (3) regulating product accumulator vessels as storage vessels under subpart G. Several commenters also suggested deleting from the HON the requirements for product accumulator vessels associated with the non-SOCMI processes subject to subpart H. The commenters preferred regulating such vessels under future MACT standards for the appropriate source category. The EPA agrees that there is need to clarify the applicability of the HON to product accumulator vessels. Previous definitions and control cost analyses for process vents have included indirect releases, such as those from distillate receivers and product separators. These emissions were clearly intended to be process vents requiring 98-percent control under subpart G. Condensates from hot wells were included in the proposed definition of wastewater and were intended to be controlled at 95 percent under the subpart G provisions for wastewater. Surge control vessels and bottoms receivers are typically smaller than storage vessels subject to the HON, and have relatively low emissions. Also, previous analyses on process vents have not been clear on the inclusion of these vessels. Thus, the EPA decided that surge control vessels and bottoms receivers will remain in subpart H to be controlled at 95 percent. The term ``product accumulator vessel'' has been deleted from the HON, and replaced with ``surge control vessels and bottoms receivers.'' The above clarification reflects the EPA's original intent regarding how the various equipment types should be regulated and is not designed to alter the stringency of the HON. 2. Storage Vessels a. Time allowance for planned routine maintenance of control devices. In the final rule, the EPA has increased the allowance for sources to complete planned routine maintenance of a control device from 72 hours per year to 240 hours per year. Several commenters asserted that the proposed 72 hours per year for routine maintenance of a control device would be insufficient for reasons including: (1) Routine maintenance of a flare may require up to 7 to 10 days per year; (2) rebricking a thermal oxidizer requires at least 7 days; (3) some States have included in incinerator air permits an allowance of 10 days per year for routine maintenance; and (4) in general, repair of boilers and water scrubbers requires more than 72 hours per year for routine maintenance. Several commenters requested that the rule allow for longer routine maintenance periods by: (1) Increasing the time allowance; (2) allowing extensions from the permitting authority; or (3) requiring that storage vessels not be filled during any routine maintenance that exceeds the 72-hour allowance. The EPA concluded that the 72-hour allowance for routine maintenance is inadequate. After reevaluating the available information, the EPA determined that increasing the time allowance to 240 hours (i.e., 10 days) would be the most reasonable approach to address the need for more time to complete routine maintenance and to be consistent with State air permitting activities. The EPA did not choose either of the other two approaches suggested by the commenters because of the additional burden associated with them. Specifically, requiring that storage vessels not be filled during any routine maintenance exceeding 72 hours would require the addition of equipment to monitor liquid level for enforcement purposes. Further, allowing for extensions for routine maintenance beyond the 72 hours would require added reporting burden for both sources and permitting authorities. While the EPA is allowing sources to utilize the full 240 hours to perform routine maintenance on each control device, the EPA does not expect that sources will utilize all 240 hours for all control devices, because many types of control devices do not require 240 hours of maintenance time per year. The EPA has included provisions in the regulation that make sources accountable for their utilization of this allowance. Sources are required to periodically (i.e., every six months) report the routine maintenance performed and the amount of time used to complete that routine maintenance. In addition, sources must indicate the routine maintenance they expect to perform during the following six months. b. AP-42 Equations for emissions averaging with storage vessels. For the final rule, the EPA will include the September 1985 version of the AP-42 equations; however, the EPA will allow sources to utilize either the September 1985 version or the October 1992 version (i.e., referenced as American Petroleum Institute Publication 2518, second edition, October 1991) of the AP-42 equations for estimating breathing losses from fixed roof storage vessels, for the purposes of emissions averaging. Whichever set of equations a source selects, the source must utilize the same set of equations for calculating breathing losses of fixed roof storage vessels for estimating both credits and debits. Two commenters recommended that the EPA update the storage vessel emissions equations in the emissions averaging section of the final rule in order to reflect the latest changes in the EPA document ``Compilation of Air Pollutant Emission Factors (AP-42)'' included in chapter 12 of supplement E, entitled ``Storage of Organic Liquids.'' The EPA agrees that sources should be given the option to use the latest AP-42 equations for estimating breathing loss emissions from fixed roof storage vessels. However, the EPA will not require that sources use these latest equations because it could be more burdensome for some sources. The EPA determined that the October 1992 equations are more site-specific and will require that sources make more measurements of tank parameters because the EPA cannot provide default values for some of the variables in the equations. Although the EPA will allow sources to choose either the 1985 or the 1992 version of the equations for estimating breathing losses from fixed roof storage vessels, the source must use the same set of equations for estimating both credits and debits from storage vessels for the purposes of emissions averaging. 3. Transfer Operations a. Determination of applicability and group status. For the final rule, the EPA has clarified many of the applicability and group determination provisions regarding transfer operations in the proposed HON. The intent of these provisions has not changed. Many commenters expressed confusion regarding whether the transfer provisions refer to arms or transfer racks being loaded. Several commenters requested that the EPA clarify that the HON is only applicable to transfers of materials from SOCMI processes and not all materials transferred at any given rack or arm. The intent of the language in proposed Sec. 63.100(b)(5) of subpart F and in the final Sec. 63.100(i) of subpart F is to assign loading racks, loading arms, or loading hoses to a chemical manufacturing process unit. If the chemical manufacturing process unit is subject to the HON, then the loading rack, arm, or hose is also subject to the HON. Once it is determined that a rack, arm, or hose is subject to the HON, group status must be determined. Group status is determined for a transfer rack. A transfer rack is defined as the collection of all arms or hoses that are assigned to a chemical manufacturing process unit that is subject to the HON. For example, if a facility has a rack that consists of eight arms and six of these arms are assigned to chemical manufacturing process units subject to the HON and the other two load petroleum refinery products not subject to HON, then the ``transfer rack,'' as defined for the HON, is made up of the six arms that are assigned to the chemical manufacturing process unit subject to the HON. Group status must be determined based on the vapor pressures and throughputs of the HAP's loaded at the arms that are subject to the HON. In cases where a rack or arm(s) has been assigned to a chemical manufacturing process unit subject to the HON, the rack or collection of arms must be controlled during transfers of all HAP's regardless of whether those HAP's were associated with SOCMI chemical manufacturing process units. The EPA determined that assigning equipment to be subject to the HON would be easier from an enforcement and control perspective, as opposed to assigning transfer operations. Also, by assigning equipment, applicability will be more obvious when other rules are promulgated affecting transfer operations under other source categories. One commenter suggested that the organic HAP partial pressure considering all the materials loaded at a specific loading arm or rack should be used to determine applicability instead of the rack-weighted vapor pressure. The EPA agrees with the commenter's suggestion. The final transfer provisions have been revised to replace the definition of rack-weighted average vapor pressure with a definition for rack-weighted average partial pressure. b. Testing and Monitoring. The following changes have been made to the testing and monitoring provisions for transfer operations: (1) 15-minute monitoring of operating parameters is required regardless of loading cycle time; (2) The requirement for a performance test has been replaced with design analysis for racks that load less than 11.8 million liters/yr; and (3) Performance test requirements have been clarified for facilities using common control devices for both process vent and transfer emissions or for emissions from multiple arms loading simultaneously. Several commenters contended that 5-minute monitoring and recordkeeping requirements for loading cycles less than 3 hours were overly burdensome and would serve no purpose. The commenters suggested that the 15-minute monitoring and recordkeeping requirements of loading cycles be made standard for all cycles in the final rule. The EPA agrees with the commenters that 5-minute monitoring intervals are not necessary. The EPA considers 15-minute monitoring to provide sufficient statistical confidence in the performance of a control device. Fifteen-minute monitoring intervals will also adequately identify performance that is outside of the approved operating parameter ranges. Two commenters contended that it was unduly burdensome to require a performance test duration of three loading cycles for infrequent loading operations. Both commenters suggested that the EPA allow owners or operators to conduct performance testing over only one loading cycle for infrequent loading operations. One commenter expressed concerns regarding simultaneous loadings and suggested that the EPA provide performance test provisions for control devices shared between racks or other emission points. The EPA agrees with the commenters' assertion that the proposed provisions for performance tests for infrequent loading operations were burdensome. The EPA determined that for owners and operators loading less than 11.8 million liters/year (3.12 million gal/yr) at a single transfer rack, requiring a performance test on three loading cycles could extend the completion of the performance test to 2 weeks or longer. The EPA's intent in requiring testing during three different loading cycles was to acquire sufficient data to ensure that a control device was operating properly. The EPA has determined that a test of one loading cycle would not provide sufficient data on the performance of the control device; thus, requiring one loading cycle to be tested would not be meaningful. Therefore, in the final rule a design evaluation is allowed instead of a test for those racks with infrequent loading (i.e., less than 11.8 million liters/year of materials loaded). Although the proposed rule did not preclude shared control devices, it was not clear how an owner or operator would demonstrate compliance. Provisions have been added to the rule to clarify that in the case of a control device being shared with process vents, the performance test required under the process vent provisions is adequate for the transfer provisions. For control devices shared among transfer racks or arms, and where materials are simultaneously loaded, the performance test requirements have been revised to be similar to the process vent provisions: three one-hour performance test runs. Simultaneous loading occurs when the beginning and ending times of loading cycles coincide and overlap such that there is no interruption in vapor flow to the control device; as one loading cycle is completed, another one begins or has already begun. 4. Wastewater a. Design steam stripper specifications. For the final rule, the EPA has revised several of the specifications for the design steam stripper. The following changes are incorporated into the final rule: (1) The design steam stripper must have ten actual trays; (2) The minimum wastewater feed temperature to the design steam stripper must be 95 deg.C; (3) The requirement to use a water-cooled condenser has been deleted; (4) The steam-to-feed ratio for the design steam stripper is 0.04 kilogram of steam for every one kilogram of wastewater; (5) The steam heat value must be at least 2,765 kJ/kg (equivalent to 690 kPa); and (6) The maximum liquid tray loading is 67,000 l/hr-m2. (i) Actual number of trays. Several commenters requested clarification regarding the EPA's intent to specify theoretical or actual trays. Based on additional analyses after the proposed rule was published, the EPA has determined that a steam stripper that is operated using 10 actual trays will achieve the required HAP target removal efficiencies. These analyses are summarized in the promulgation BID volume 2D and details of the analysis are in docket A-90-23. (ii) Minimum wastewater feed temperature. The proposed rule specified 35 deg.C as the feed temperature of wastewater to the steam stripper. However, in the design analysis for the wastewater provisions in both the proposed and final HON, the EPA has assumed that the feed stream is heated to 95 deg.C before it enters the design steam stripper. The feed stream is pre-heated to 95 deg.C by using a heat exchanger to recover heat from the treated wastewater. The temperature of 35 deg.C, which was inadvertently designated as the feed temperature in the proposed rule, refers to the temperature of the wastewater before it is pre-heated by the heat exchanger and sent to the design steam stripper. The EPA has corrected this error and included 95 deg.C in the final rule as the minimum wastewater feed temperature to the steam stripper after the wastewater has been pre- heated. (iii) Condenser. The proposed rule required that a water-cooled condenser with a maximum primary condenser outlet vapor temperature of 50 deg.C be used in conjunction with the design steam stripper. Several commenters questioned why the EPA required the use of a water- cooled condenser as part of the design steam stripper specifications. The commenters suggested that the requirements for treatment devices in section 63.138(h) were sufficient to control HAP emissions from treatment devices. While the EPA agrees to eliminate the condenser from the design steam stripper, it is clarified that a primary condenser, if used, does not count toward the 95-percent control requirement because this control requirement applies to non-condensibles. (iv) Steam-to-feed ratio. Although no specific comments were received on this issue, the EPA updated this number as part of the analysis to revise the design steam stripper. The proposed rule required a steam-to-feed ratio of 0.096 kilograms of steam for every one kilogram of wastewater. The revised steam-to-feed ratio of 0.04 kilograms of steam for every one kilogram of wastewater optimizes the efficiency of the design steam stripper to remove HAP's from wastewater. The steam heat value specified for the design steam stripper is 2765 kJ/kg, which is based on saturated steam at 690 kPa. This parameter is specified in the design because use of a lower quality steam would reduce the fraction of HAP's removed from the wastewater treated by the design steam stripper. (v) Maximum liquid tray loading. The maximum liquid tray loading in the proposed rule was 39,900 l/hr-m 2. Because the liquid tray loading is dependent on several other steam stripper parameters, including the steam-to-feed ratio, the EPA has revised this input parameter for the design steam stripper as a result of the revised design analysis. The design analysis indicates that the revised maximum liquid tray loading is 67,000 l/hr-m2. (vi) Materials of construction. Although the rule does not specify a particular type of steel that the SOCMI must use to construct the design steam stripper, the cost estimates for the final rule include the cost of stainless steel construction. The cost estimate for the steam stripper in the proposed rule was based on carbon steel construction. Numerous comments on this issue requested that the EPA reevaluate the cost of constructing a design steam stripper based on the use of stainless steel for construction. Commenters in favor of stainless steel construction stated that stainless steel was stronger, more durable, and more reliable than carbon steel. Also, stainless steel is the minimum grade of building material that would be used by the industry because of corrosion problems associated with carbon steel. The EPA received no comments in favor of carbon steel construction. The EPA has revised the cost estimate for the design steam stripper using stainless steel and has determined that the design steam stripper remains a cost-effective option for treating wastewater. b. Fraction removed (Fr). In the final rule, the EPA has revised the required Fr values (i.e., strippabilities) and assigned an Fr for each of the individual compounds regulated by the wastewater provisions (i.e., compounds listed on table 9). Several commenters requested that the EPA: (1) Re-evaluate the Fr estimates in the proposed rule using actual Henry's law constants at 100 deg.C; and (2) Assign a better estimate of individual compound-specific Fr values rather than use the strippability groups. In response to comments, the EPA conducted a literature search to determine peer-reviewed Henry's law constants at 25 and 100 deg.C, and selected the best estimates available for each compound. The revised Henry's law constants at 100 deg.C were used to estimate Fr values for each of the 76 compounds in the wastewater provisions of the final rule. The report documenting the development of the constants is titled ``Henry's Law Constants for the 83 HAP's Regulated in the Proposed HON Wastewater Provisions,'' and is provided in Docket A-90-23. In the proposed rule, each of the compounds listed on table 9 was assigned to one of these strippability groups. The strippability groups represented a range of actual strippabilities with a single target removal efficiency (i.e., strippability). The EPA agreed with commenters that assigning HAP's to a specific strippability group could preclude compliance with the standard for some compounds. Therefore, the EPA generated compound-specific Fr values based on the revised Henry's law constants for each of the compounds listed in table 9 of subpart G. Additionally, the EPA has revised the proposed compliance option that required compounds listed on table 9 of subpart G to meet the target removal efficiencies that were associated with the strippability groups. The compliance option in the final rule requires that the owner or operator treat compounds to meet their individual Fr's, which are assigned in table 9 of subpart G. c. Emission estimates--(i) Wastewater models. For the final rule, the EPA has revised the emission models for lift stations, junction boxes, open sumps, trapped drains, and weirs using a study provided by one commenter, in which the emissions of organic HAP's were measured. The EPA reviewed the information and determined that the report and source data were appropriate to use to improve the emission models. The air emission model for weirs was modified to account for gas-phase resistance. These revised models also incorporate an approach for modeling site-specific configurations of lift stations, junction boxes, sumps, drains, and weirs that are currently used by the SOCMI. The models used to calculate the Fe's are described in ``Estimation of Air Emission Factors from Airflow in Wastewater Collection Systems,'' November 30, 1993. (ii) Collection and treatment scenarios. The EPA also revised the SOCMI source wastewater collection and treatment scenarios based on information provided by one commenter, EPA staff observations, and State and EPA environmental regulatory enforcement representatives from Texas, Louisiana, and New Jersey. Several commenters stated that baseline emission estimates should be revised based on emission data and SOCMI source scenarios that were submitted to the EPA during the public comment period. The EPA considered and incorporated, where appropriate, data that were submitted by commenters. (iii) Fraction emitted (Fe) values. The revised Fe's in the final rule are based on two different wastewater collection and treatment system scenarios with three different levels of control, and with each control level weighted based on the expected level of occurrence. The three control levels and the corresponding fraction of occurrence are: (1) Uncontrolled = 0.50; (2) medium degree of control = 0.40; and (3) higher degree of control = 0.10. Values for Fe for individual compounds were calculated for each of the two scenarios and the control distributions summarized above. The resulting two control weighted average Fe's for each individual compound (one for each scenario) were averaged together, resulting in the final Fe values. This procedure is described in detail in the memorandum, ``Estimation of Air Emissions from Model Wastewater Collection and Treatment Plants Systems,'' February 2, 1994. The EPA used revised scenarios and emission models in conjunction with the revised Henry's law constants to revise the Fe values for each compound listed on table 9. The EPA used the revised Fe values to calculate the baseline emission estimates for the final rule and to re- evaluate which organic HAP's should be subject to the wastewater provisions of the HON. Based on the revised Fe's, the EPA has deleted seven compounds from the final rule. Each of these compounds is unlikely to be emitted in significant quantities from the collection system (due to the low Fe value) and will be readily biodegraded upon reaching the biological treatment unit. Several commenters stated that some of the HAP's regulated by the proposed HON are non-volatile or semi-volatile, are not likely to be emitted from wastewater, and should be deleted. Based on the revised Fe values, the EPA has removed the following seven compounds from the wastewater provisions of the final rule: Aniline (62533); 2- chloroacetophenone (532274); o-cresol (95487); 3,3-dimethylbenzidine (119937); diethylene glycol diethyl ether (112367); diethylene glycol dimethyl ether (111966); and ethylene glycol monoethyl ether acetate (111159). An increase in baseline emission estimates for wastewater of 9 percent resulted from the emission estimate revisions. The primary reasons for the change were: (1) Revised Henry's law constants; (2) Revised wastewater emission models for lift stations, junction boxes, open sumps, and open drains; and (3) Revised scenarios and Fe values. d. Wastewater tanks. In the final rule, the EPA requires any owner or operator of a SOCMI source who is subject to the wastewater tank provisions in Sec. 63.133 of subpart G to calculate the vapor pressure and the capacity of the tank in order to determine the applicable compliance options. The proposed rule did not require the owner or operator to determine the vapor pressure or the tank capacity, but rather required the same compliance options for wastewater tanks regardless of size and vapor pressure. Several commenters requested the following changes to the proposed wastewater tank provisions including: (1) That wastewater tanks be managed in accordance with the proposed storage vessel provisions; (2) That wastewater tank requirements be based on the partial pressure of the liquid in the tank; (3) That wastewater tank requirements be based on the capacity of the tank; and (4) That wastewater tanks operated under negative pressure be exempt from using Method 21 for leak detection. In response to comments, the EPA has incorporated several changes to the wastewater tank provisions. The EPA continues to require emission controls on all wastewater tanks that manage Group 1 wastewater streams or residuals generated from Group 1 wastewater streams. However, the EPA has included capacity and maximum partial vapor pressure thresholds that are consistent with those of the storage vessel provisions. The EPA also is allowing the owner or operator to demonstrate compliance with the wastewater tank provisions by installing only a fixed roof if the tank meets any of the following criteria: (1) Is less than 75 m\3\; (2) is greater than or equal to 75 m\3\ and less than 151 m\3\ and has a maximum true vapor pressure less than 13 kPa; or (3) is greater than or equal to 151 m\3\ and has a maximum true vapor pressure less than 5.2 kPa. The EPA has determined that a fixed roof is sufficient to suppress emissions from any wastewater tank that meets the preceding criteria. In addition, the EPA has dropped the requirement for annual Method 21 inspections on wastewater tanks. In the final rule, Method 21 inspections are required initially and annual visual inspections are required. Furthermore, the EPA has added a provision to the final rule which states that any wastewater tank operated and maintained under negative pressure is not required to comply with the requirements for leak detection by Method 21 of 40 CFR part 60, appendix A because it cannot emit. e. Containers. In the final rule, the EPA has included a de minimis capacity of 0.1 m\3\ (i.e., approximately 26.4 gal) in the definition of container, below which the container is not subject to the HON. For the purpose of monitoring and submerged filling, the EPA distinguishes between containers that are less than or equal to 0.42 m\3\ (i.e., approximately 110 gal) and those that exceed 0.42 m\3\. Furthermore, the EPA has changed the requirements for a submerged fill pipe. In the final rule, a submerged fill pipe outlet shall extend to no more than 6 inches or within two fill pipe diameters of the bottom of the container while the container is being filled. Submerged filling is not required for containers with capacities less than or equal to 0.42 cubic meters. The proposed rule did not distinguish between container capacities. All containers regardless of size were required to meet the same requirements. The EPA received comments in favor of changing the monitoring requirements and establishing a de minimis container size. Specifically, commenters asserted that the HON should not apply to either very small containers which include lab sample bottles or containers with small capacities such as 30 gallons or 55 gallons. Commenters also claimed that the requirement to use Method 21 for containers, particularly those that are on site for a short time, would be burdensome. In response to comments, the EPA has established a de minimis capacity of 0.1 m\3\, which exempts lab bottles and other very small containers from the HON. The EPA has also provided an additional compliance option for leak detection monitoring for containers with capacities less than or equal to 0.42 m\3\. If a container has a capacity less than or equal to 0.42 m\3\, the owner or operator may either: (1) Use Method 21 initially to demonstrate that the container is not leaking; or (2) document that the container meets DOT specifications and testing requirements in 49 CFR part 178. The EPA has determined that if an owner or operator is in compliance with the DOT specifications and testing requirements in 49 CFR part 178, no additional requirements are necessary to ensure that the containers do not leak. The owner or operator must maintain records documenting the Method 21 test for non-DOT containers. For DOT-approved containers, the owner or operator does not need to keep a record because compliance may be determined by a visual inspection. The EPA also has reduced the monitoring burden for larger containers with a capacity greater than 0.42 m\3\. Whereas the proposed rule specified the use of Method 21 initially and annually, the final rule requires the use of Method 21 initially and allows annual visual inspections thereafter. f. Method 304 and method 305. No major changes have been made to Method 304. However, the EPA has included both Method 304A and 304B in the final rule. Commenters requested that Method 304 allow more flexibility in choice of laboratory equipment, clarifier design, and some operating parameters. The EPA agreed with the commenters and has added options to increase the flexibility of the method, such as allowing air cylinders in addition to oxygen cylinders to aerate the microbial population. The additional flexibility added to the method does not reduce the accuracy or precision of the method results and could in some cases improve the results by better representing the actual biological treatment process. Changes made to the final Methods 304A and 304B are in section 4.0 of BID volume 2E. Several commenters misunderstood the requirements of Method 305. The EPA discusses clarifications to the method in volume 2B of the BID. One commenter questioned why the EPA developed Method 305 when other methods, such as the 600 series for water and wastewater, were available. Another commenter was concerned whether the test method results are realistic. To determine the significance of HAP emissions from wastewater, it is more important to know how likely a HAP is to leave the wastewater and go into the atmosphere than to know the actual concentration of the HAP in the wastewater. The EPA developed Method 305 to provide a relative measure of the emission potential of wastewater. Other methods measure the actual concentration of pollutants; no other methods define the relative measure of emission potential. Although the results of Method 305 do not necessarily represent the actual pollutant concentration in wastewater, the test method results are realistic--the results measure the relative emission potential. The parameters of the test method were chosen to define emission potential based on mathematical modeling of actual data collected from various sources throughout the country. In addition, the regulation requires that concentration be reported in terms of Method 305 results; it does not require the owner or operator to use Method 305. The owner or operator may use any method that has been validated by section 5.1 or 5.3 of Method 301 and converted to Method 305 results using the appropriate Fm factor. g. Water seal controls. The EPA revised the requirements for water seals. In Sec. 63.137(e) of the final wastewater provisions if a water seal is used on a drain hub receiving a Group 1 wastewater stream, the owner or operator shall either extend the drain pipe discharging the wastewater below the liquid surface in the water seal, or install a flexible cap (or other enclosure which restricts wind motion) that encloses the space between the drain discharging the wastewater to the drain hub receiving the wastewater. VI. Summary of Significant Comments and Changes To Proposed Subpart H Approximately 60 letters commenting on proposed subpart H were received; most of these letters contained multiple comments. The EPA's responses to these comments can be found in the BID referenced in the ADDRESSES listing in this preamble. The most significant comments and responses for the equipment leak standard (subpart H) are summarized in this section of the preamble. A. Applicability 1. SOCMI Processes Many commenters requested that EPA make the list of SOCMI processes in subpart H consistent with the list in subpart F and that the EPA correct errors in nomenclature and CAS numbers provided. Some of these commenters also recommended consolidation of all the applicability provisions for SOCMI processes in subpart F. As discussed in section V.A.1 of this preamble, the lists of SOCMI processes have been consolidated into a single list in subpart F and errors in CAS numbers have been corrected. The revised subpart F presents all the criteria for determining applicability of the HON for SOCMI processes. The EPA believes this revised organization will be easier and more efficient to use. 2. The Seven Non-SOCMI Processes At proposal, the provisions of subpart H applied to both SOCMI processes and to equipment handling specific chemicals for seven listed non-SOCMI processes. Subparts F and H in the proposed rule presented the applicability provisions for both SOCMI and non-SOCMI processes. In the final rule, the applicability provisions for the non-SOCMI processes are presented in a separate subpart, subpart I, from the SOCMI applicability provisions which are specified in subpart F. Subpart I identifies the specific non-SOCMI processes that are subject to the provisions of subpart H. In addition, subpart I presents definitions and general information on compliance, reporting, and recordkeeping. a. Separate from SOCMI category. A number of commenters thought that the non-SOCMI processes subject to subpart H should be regulated separately from the SOCMI processes. These commenters thought that combining the non-SOCMI processes in a standard for SOCMI processes could result in piecemeal regulation, overlapping section 112(d) regulations, and confusion for regulatory agencies. A few of these commenters also argued that regulation of the non-SOCMI processes should be deferred until the rest of the section 112(d) emission standard is issued for each specific non-SOCMI process. The EPA agrees with the commenters' suggestions for reorganization of the regulatory provisions into separate subparts. The applicability provisions for the non-SOCMI processes have been placed in subpart I. Subpart I refers to subpart H for the substantive requirements. As discussed in section VI.A.2.b through e of this preamble and in the BID, subpart I contains revised definitions for some of the non-SOCMI processes. The definitions were revised to specifically identify the intended processes and to directly correspond to the categories listed in the source category list (57 FR 31576). The EPA expects that these changes will minimize the possibility for confusion and development of overlapping regulations. The EPA does not agree with the suggestion to defer the applicability of the equipment leak standard to the non-SOCMI processes until requirements for the other emission points are issued. This change suggested by the commenters is not consistent with the spirit of the negotiated agreement. b. Chlorine production. Under the negotiated agreement, chlorine production processes that used carbon tetrachloride as a diluent for nitrogen trichloride or as scrubbing liquid to recover chlorine from the liquefaction of tail gas would implement the equipment leak provisions for equipment in 5 percent, or greater, carbon tetrachloride service. At the Fourth Meeting of the Parties to the Montreal Protocol in November 1992, the United States Government and the Other Parties agreed to accelerate the phase-out schedule for carbon tetrachloride by requiring a reduction from 1989 levels of 85 percent in 1995 and a complete phase-out by January 1, 1996. Because of this development, chlorine producers will cease use of carbon tetrachloride by January 1, 1996. Therefore, several commenters questioned the value of continued application of subpart H to chlorine production processes. The EPA agrees that the reasons for application of the negotiated equipment leak rule to chlorine production processes have significantly diminished and will disappear entirely in the next 2 years. Therefore, to avoid essentially duplicative regulation of the same operations, chlorine production has been removed from the list of seven additional processes subject to subpart H. c. Pesticide production. One commenter argued that the proposed definition of ``pesticide production'' defines a source category that is broader than any category in the agricultural chemical production industry grouping identified in the List of Source Categories (57 FR 31576), or in the proposed Schedule for Promulgation of Emission Standards (57 FR 44147). The commenter noted that only the production of Captafol, Captan, Chlorothalonil, Dacthal(tm), and Tordon(tm) were listed in 57 FR 31576 or 57 FR 44147 as being specifically regulated by the HON equipment leak standard. The commenter argued that if EPA wants to update the source category list, EPA must comply with statutory requirements to include only categories of major sources and area sources where a finding of adverse health effects has been made. The commenter recommended that the definition of pesticide production in subpart H be modified to regulate equipment leaks only from the production of Captafol, Captan, Chlorothalonil, DacthalTM, and TordonTM. The definition for pesticide production in proposed subpart H was developed in the regulatory negotiation before creation of the source category list. The source category list and schedule (57 FR 31576 and 57 FR 44147) identifies the pesticide production processes that EPA had information on at the time of the negotiations on the equipment leak standard. Therefore, subpart H is being applied only to the five production processes identified in the source category list (production of Captafol, Captan, Chlorothalonil, DacthalTM, and TordonTM). As EPA obtains information on other pesticide processes, these processes will be added to the source category list in the future and standards will be developed. d. Chlorinated hydrocarbon use. Numerous inquiries have been received from members of the public questioning whether, through the ``chlorinated hydrocarbon use category'' in subpart H, the EPA intended subpart H to apply to all operations that use chlorinated organic solvents. A few written comments were also received requesting clarification that this definition applied to production operations only. The term ``chlorinated hydrocarbon use'' was a label created in the regulatory negotiation to refer to a number of specific miscellaneous chemical manufacturing processes that used chlorinated solvents as a solvent or processing aid. Examples of the specific processes included under this term are production of polycarbonate and production of polysulfide rubber. The provisions of subpart H were intended to apply only to the specific types of processes listed in the definition and not to all use of chlorinated organic solvents. Because of the confusion created by the label applied to these processes, the final rule does not use the term chlorinated hydrocarbon use. Instead, subpart I specifically identifies the processes subject to subpart H. e. Miscellaneous butadiene use. Comments were received requesting that the definition of this term clarify that these are processes producing chemicals or chemical products. The EPA agrees that ``miscellaneous butadiene use'' refers to a number of miscellaneous chemical manufacturing processes that use butadiene to produce other chemicals or chemical products. To eliminate the possibility of confusion regarding the applicability, subpart I lists the specific processes subject to H and the term ``miscellaneous butadiene use'' is not used in the final rule. B. Compliance Schedule 1. Consistency with Subpart G Unlike most standards, compliance with the provisions of subpart H is phased in by type of chemical manufacturing process. The proposed subpart H divided the regulated processes into five distinct groups to which the provisions would apply beginning 6 months after publication of the final rule in the Federal Register. Thereafter, the rule would apply to another group of processes every 3 months. The final rule for subpart H uses the same approach. In the proposed and final provisions in subpart G, sources are required to comply by 3 years from date of publication of the final rule in the Federal Register. Many commenters requested a compliance schedule for subpart H similar to the 3-year schedule provided under subpart G. Several commenters argued that the 6-to-18-month compliance period in proposed subpart H did not take into consideration the implementation problems that could arise during installation of required equipment. A few commenters thought that proposed subpart H did not permit applications for compliance extensions. The EPA does not agree with the commenters that sources should be allowed up to 3 years to comply with the provisions in subpart H. Subpart H consists of a combination of work practice requirements for many equipment components and equipment standards for compressors, sampling systems, open ended lines or valves, and pressure relief valves. Unlike the requirements in subpart G, the equipment required by subpart H should not involve long periods of time for design, construction, and installation. The commenters did not provide any information that would justify establishing a source-category-wide compliance schedule for subpart H similar to that provided for subpart G. The EPA recognizes that there may be circumstances present in individual facilities where an extension is appropriate for compliance with certain requirements in subpart H. In such cases, the owner or operator may request an extension of compliance through the provisions of 40 CFR 63.6(i)(4). Section 63.182(a)(6) has been added to subpart H to clarify that extensions of compliance may be requested if additional time is necessary for installation of equipment required by subpart H. 2. Phase-In of Valve Provisions The proposed standard for valves was structured to be implemented in three phases, with lower leak definitions in each phase. In the first and second phases of the proposed standard, monitoring was to be conducted quarterly. In the third phase of the proposed standard, the monitoring frequency would be determined by the percent leaking valves, with the best performers having an annual monitoring requirement. The final standard retains the phased-in implementation of the proposed standard and the proposed monitoring frequencies. Many commenters requested that the rule be modified to allow facilities to begin Phase III of the valve provisions on the applicability date. Some of these commenters thought facilities that qualify for reduced monitoring frequency should be allowed to do so at the earliest possible date. Other commenters thought the rule should allow the owner or operator to elect the monitoring frequency based on the source's current status since records may not have been retained. The commenters submitted that disallowing early adoption of Phase III would penalize facilities that have implemented the proposed rule before required or that have established low leak rates through existing programs. The EPA agrees that the final rule should allow owners or operators the flexibility to initiate Phase III at any time, and it was intended that this option would be available. Subpart H has been revised to clarify this point. This clarification does not, however, allow an owner or operator to elect to use reduced monitoring frequencies without Method 21 data to document achievement of lower leak rates for the required periods. C. Selection of Requirements 1. Closed Vent Systems and Control Devices At proposal, both subparts G and H contained requirements for monitoring inspections of closed vent systems. In the final rule, the inconsistencies between the proposed provisions in subparts G and H have been eliminated and the two sets of provisions have been coordinated. The final subparts G and H each include provisions for closed vent systems. Several commenters recommended that all provisions for closed vent systems be consolidated in subpart H and all inconsistencies eliminated. These commenters speculated that different provisions for closed vent systems serving different operations would increase confusion, recordkeeping costs, and potential for recordkeeping violations. Some of these commenters questioned the basis for treating valves, connectors, and compressors in closed vent systems separately from the same equipment in the process. The commenters noted that the equipment is either in low pressure or vacuum service and the annual inspection requirements are of no environmental benefit. The EPA evaluated the commenters' suggestions and agrees that it would be appropriate to have a consistent set of provisions for closed vent systems in the rule. A uniform set of provisions for closed vent systems will benefit both State and Federal enforcement programs and industry by both reducing review time and complexity of record systems. Because subpart G also included requirements for inspections of equipment other than closed vent systems, the closed vent system provisions in subpart G were not consolidated into subpart H. The EPA also reevaluated the provisions requiring annual Method 21 monitoring of closed vent systems. Closed vent systems in chemical plants and refineries are constructed of piping and connections and are operated at low pressures or under vacuum. An assessment of recent data and experience from implementation of existing standards under 40 CFR part 60 and part 61 showed that only rarely are leaking connectors and other equipment identified through the annual Method 21 inspections of closed-vent systems. As discussed in the preamble to the proposed rule (57 FR 62666 and 57 FR 62676), connectors have very low leak frequencies and once leak-tight they remain leak-tight. Consequently, the final rule only requires an initial Method 21 demonstration that all connections and other equipment in closed vent systems are operated with instrument readings less than 500 ppm and annual inspections for indications of leaks (visual, olfactory, or audible). The EPA believes that this requirement along with the requirement for flow indicators or car seals on by-pass lines that could divert emissions from the control device to the atmosphere will ensure emissions are controlled as required. The EPA would like to clarify that the provisions for inspections of closed vent systems do not apply if the closed vent system is operated in vacuum service. The closed vent systems provisions in section 63.148 of subpart G and section 63.172 of subpart H have been revised to clarify that these provisions do not apply if the system is operated under vacuum. 2. Inaccessible Connectors Proposed subpart H excluded connectors that ``were unable to be reached from a 7.6-meter (25-foot) portable scaffold on the ground, and were greater than 2 meters above a support surface'' from the monitoring provisions. In the final rule, EPA has revised this definition to reflect concerns with safety of monitoring connectors accessible only via portable scaffolds and to clarify the original intent. Several commenters requested that the definition of inaccessible connectors be revised to be any that are greater than 2 meters above a support surface and, thus, the same as the difficult-to-monitor valve definition. The commenters objected that portable scaffolds presented safety and practical concerns due to limitations on access due to equipment spacing, explosion hazards, and risks of damaging electrical cables and piping. During the Committee discussions in negotiation of these provisions, the portable scaffolding envisioned was a wheeled scissor- lift platform that would sit on the ground below the monitoring or repair location. Portable scaffolding was not envisioned as including field-erected scaffolding or movement over grassed or unstable stone covered areas below pipelines because of concerns these operations would endanger the monitoring personnel's lives. Because the proposed rule's language was not clear on this point, the EPA agrees that clarification of the term ``portable scaffold'' is warranted. A definition has been added to the final rule. The EPA believes that clarifications in subpart F to the definition of production process should also address commenters' concerns regarding monitoring connectors in interunit pipelines. 3. Response Factor Adjustments The proposed standard required correction of the Method 21 instrument readings if the response factor for the process fluid was 3 or greater, and documentation of the response factor for every process stream subject to the standard. The proposed standard also specified the use of methane as the sole reference gas for the response factors. The final standard retains the use of methane as the sole basis for response factors, but revises the requirements for response factor adjustment to ensure the instrument meets specifications of Method 21. The final standard, thus, does not require process stream response factor adjustments. Several commenters objected to the proposed requirement to determine response factors for process streams arguing that most factors are less than 3, the difference in number of leaks detected will be small, and the program complication will be immense. Another issue with the proposed requirement was that the equation for calculating response factors of mixtures was applicable only to gas mixtures. For mixtures of liquids, the equation would have to be adjusted by the vapor pressure of each component. A number of commenters were also concerned that the stipulation of methane as the sole reference gas would preclude the use of some monitoring instruments. As discussed in the proposed notice (57 FR 62682), the Committee decided to limit the acceptable range of response factors to ensure that the effect of the standard could not be significantly altered by the monitoring instrument used or by the composition of streams monitored. At the time of the negotiations, few response factors at 500 ppm were available and it was believed that most SOCMI processes would have no more than four to five compounds present in any given stream. Based on these assumptions, the Committee thought that the requirement to correct any response factors greater than 3 would not impose unproductive costs or be especially burdensome. The EPA reevaluated this proposed requirement in light of the public comments and the experience gained by chemical plants that have implemented the negotiated rule. Experience with the correction for response factors has shown the proposed provisions to be significantly more burdensome than originally anticipated. Specifically, several facilities have reported that instead of quantifying 4 to 5 compounds in some streams, they are quantifying 50 to 100 compounds. In some cases, owners or operators have elected to correct all instrument readings by the highest response factor for any compound in the process rather than undertake the effort associated with the stream specific corrections. The EPA also reviewed the reasons the Committee originally considered requiring adjustment of screening values by response factors. The response factor adjustment originated in Committee discussions on studies to improve the emission estimates. (Response factors are used to correct instrument readings to indicate actual concentrations for developing emission estimates.) The appropriateness of adjusting screening values in the leak detection and repair provisions was not considered. These adjustments will not change the emission reductions achieved from implementing the standard. Therefore, EPA believes that eliminating this provision does not change the effect of the standard and preserves the Committee's intent of minimizing unproductive effort. The final standard requires the owner or operator to use a monitoring instrument that meets the specifications of Method 21 of appendix A of 40 CFR part 60. The proposed provisions in Sec. 63.180(b)(6) have been removed from the standard. It has been clarified that the leak definitions are expressed in terms of total VOC, and not speciated concentration readings. A number of commenters also objected to the specification of methane as the calibration gas for the Method 21 monitoring. These commenters were concerned that this specification precluded the use of photoionization detectors and recommended the rule allow use of calibration gas best suited to the detector. The provisions in Sec. 63.180(b)(4) designate methane as the calibration gas to identify methane as the sole reference gas for calculation of response factors. If an instrument has a poor response or no response to methane, a calibration gas other than methane may be used. In cases where the instrument's response factor is greater than 10, the instrument readings must be converted to a methane basis as described in section 3.2 of Method 21. Section 63.180(b)(4) has been clarified on this point. D. Recordkeeping and Reporting 1. Consistency With Subpart G and General Provisions Reporting Requirements Proposed subpart H required owners or operators of sources to submit an initial report and semiannual reports thereafter. The initial reports were to be submitted within 90 days of the applicability date for each group of chemical production processes. In the final rule, the system of reports in subpart H has been revised to be compatible with the five-report system of subpart G, and the relationship of the general provisions to subpart H has been clarified. Several commenters suggested that subpart H use a system of reports similar to that specified in subpart G and that the final standard should provide a means to coordinate reporting for processes in different applicability groups. The commenters urged EPA to make these changes to facilitate management and enforcement of the provisions. A few commenters questioned the need for semiannual reporting when 70 to 95 percent of the components at a facility would be monitored on an annual basis. Additionally, the need for certain reports was questioned by several commenters. The EPA agrees that, to the extent possible, reporting requirements for subpart H should be consistent with those of subpart G. A consistent system will, as noted by the commenters, make management of the program easier for the permit authority as well as the source. As proposed, an owner or operator of a source with processes in each of the five applicability groups could be required to submit as many as eight reports each year. Therefore, to streamline reporting requirements and minimize potential confusion, the following changes have been made to the proposed requirements: (1) Submit the compliance notification report no later than 90 days after the applicability date for the group of chemical processes and the periodic reports every 6 months thereafter; (2) Allow the source to adjust the reporting schedule to combine the periodic reports for subpart H with those for subpart G once the source comes into compliance with the provisions in subpart G; and (3) Consolidation of several special reports into the periodic report. The final standard does not allow annual reporting as requested by several commenters. Although many components may be monitored on an annual basis, the monitoring frequency for pumps and agitators is monthly and annual reporting would not be consistent with the reporting system in subpart G. The operating permit provisions of the Act, section 504(a), also requires reporting to be at least semiannual. Additionally, unless all units at a source are on the same monitoring schedule, the source would have to submit multiple annual reports. The EPA believes that consolidating the reporting into semiannual reports for G and H is more efficient for both industry and enforcement agencies. 2. Burden of Recordkeeping and Reporting Requirements The vast majority of the comments received on proposed subpart H concerned the burden of the recordkeeping and reporting requirements. Some commenters argued that the proposed subpart H would require from 1.5 to 2.5 person-years effort for the initial report and from 1 to 1.5 person-years effort for subsequent reports. These commenters thought that the proposed requirements were not necessary to ensure enforceability of or compliance with the provisions. Many comments were received regarding documentation of equipment not subject to the provisions, compatibility with computerized systems, and duplicative records and reports. The detailed summary of these comments and EPA's response is provided in chapter 5 of promulgation BID volume 2A. In light of these comments, EPA reevaluated the proposed requirements to ensure that only those records and reports essential for enforcement of the standard are required. This review showed that some of the commenters' concerns arose from a lack of clarity in the proposed standard regarding actual records required for some of the provisions and other concerns arose from overlapping or duplicative requirements. It was also determined that some provisions should be redrafted to be compatible with computerized data management systems and the revised provisions would still provide the information necessary to demonstrate compliance. Examples of such changes include: allowing a source to maintain on file a written procedure outlining the conditions for delay of repair and requiring certain records only for nonautomated systems. The EPA also reviewed the proposed standard to identify implied recordkeeping requirements and to specify all the required records in Sec. 63.181. VII. Administrative Requirements A. Docket The docket is an organized and complete file of all the information considered by the EPA in the development of this rulemaking. The docket is a dynamic file, since material is added throughout the rulemaking development. The docketing system is intended to allow the public to readily identify and locate documents so that they can effectively participate in the rulemaking process. Along with the statement of basis and purpose of the proposed and promulgated standards and the EPA's responses to significant comments, the contents of the docket, except for interagency review materials, will serve as the record in case of judicial review [section 307(d)(7)(A)]. B. Executive Order 12866 This regulation has been reviewed in accordance with Executive Order 12866. Under the terms of the Order, the Administrator has assessed the potential costs and benefits of this regulatory action. The methods for and results of these cost and benefit analyses are described in the HON's Regulatory Impact Analysis (RIA). The RIA was included in the HON docket at proposal, and thus it was made available for public comment. Executive Order 12866 also requires that the record for ``significant'' rules include an assessment of the potentially effective and reasonably feasible alternatives to the planned action. The potentially effective and reasonably feasible alternatives to the control requirements in the HON were also analyzed as part of the rule development process. The methods for and results of these analyses are described in the HON's Background Information Document (BID). The BID was included in the HON docket at proposal, and thus it was also available for public comment. In addition, many of the alternative requirements considered by the Administrator were described in the preamble for the HON proposal. The potential costs associated with alternatives selected by the Administrator for this rule are primarily the result of statutory requirements. All elements of the cost that are not directly attributable to statutory requirements were deemed appropriate because the Administrator determined that they were necessary for administering this program effectively and efficiently. In assessing the potential costs and benefits--both quantitative and qualitative--of this rule, the Administrator has determined that the benefits justify the costs. Burdens specifically associated with information collection requirements are identified and explained in the next section of this preamble under the heading Paperwork Reduction Act of 1980. The Administrator has also determined that this regulatory action does not unduly interfere with State, local and tribal governments in the exercise of their governmental functions. C. Paperwork Reduction Act The information collection requirements in this rule have been submitted for approval to the OMB under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An Information Collection Request document has been prepared by the EPA (ICR No. 1414.02), and a copy may be obtained from Sandy Farmer, Information Policy Branch, EPA, 401 M Street, SW. (2136), Washington, DC 20460, or by calling (202) 260-2740. These requirements are not effective until OMB approves them and a technical amendment to that effect is published in the Federal Register. This collection of information has an estimated reporting burden averaging 1,400 hours per response, and an estimated annual recordkeeping burden averaging 5,400 hours per respondent. These estimates include time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding the burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Chief, Information Policy Branch, EPA, 401 M Street, SW., (Mail code 2136); Washington, DC 20460; and to the Office of Information and Regulatory Affairs, Office of Management and Budget, Washington, DC 20503, marked ``Attention: Desk Officer for EPA.'' D. Regulatory Flexibility Act The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires EPA to consider potential impacts of proposed regulations on small ``entities.'' If a preliminary analysis indicates that a proposed regulation would have a significant economic impact on 20 percent or more of small entities, then a regulatory flexibility analysis must be prepared. Regulatory impacts are considered significant if any of the following criteria are met: (1) Compliance increases annual production costs by more than 5 percent, assuming costs are passed on to consumers; (2) Compliance costs as a percentage of sales for small entities are at least 10 percent more than compliance costs as a percentage of sales for large entities; (3) Capital costs of compliance represent a ``significant'' portion of capital available to small entities, considering internal cash flow plus external financial capabilities; or (4) Regulatory requirements are likely to result in closures of small entities. Firms in the chemical industry are classified as small by the Small Business Administration (SBA) if employment is less than 500 to less than 1,000 employees depending on the particular Standard Industrial Classification (SIC) of the firm. The firms classified as small by this definition are only small in a relative way because an average firm with 500 employees in the SOCMI industry has an average sales of over $180 million. Of the 66 firms analyzed in the economic impact analysis, only 10 have fewer than 1,000 employees. Since these 10 are only 15 percent of the firms analyzed, they do not constitute a substantial number (usually 20 percent). The economic analysis also projected generally small impacts (87 percent of the analyzed sample are projected to have output changes of less than 2 percent). Therefore, the standard is not expected to have a significant economic impact on a substantial number of small firms. Pursuant to the provisions of 5 U.S.C. 605(b), I hereby certify that this rule will not have a significant economic impact on a substantial number of small business entities. E. Review This regulation will be reviewed 9 years from the date of promulgation. This review will include an assessment of such factors as evaluation of the residual health risks, any overlap with other programs, the existence of alternative methods, enforceability, improvements in emission control technology and health data, and the recordkeeping and reporting requirements. Table 1.--National Primary Air Pollution Impacts in the Fifth Yeara ---------------------------------------------------------------------------------------------------------------- Baseline emissions (Mg/ Emission reductions yr) --------------------------------------- Emission points -------------------------- (Mg/yr) Percent --------------------------------------- HAP VOCb HAP VOCb HAP VOCb ---------------------------------------------------------------------------------------------------------------- Equipment leaks............................... 62,000 79,000 54,000 69,000 87 87 Process vents................................. 310,000 600,000 300,000 500,000 97 83 Storage vesselsc.............................. 14,000 14,000 7,300 7,300 52 52 Wastewater collection and treatment operations 130,000 490,000 100,000 370,000 77 76 Transfer loading operations................... 900 900 500 500 56 56 ----------------------------------------------------------------- Totalc.................................... 520,000 1,200,000 460,000 950,000 88 79 ---------------------------------------------------------------------------------------------------------------- aThese numbers represent estimated values for the fifth year. Existing emission points contribute 84 percent of the total emission reduction. Emission points associated with chemical manufacturing process equipment built in the first 5 years of the standard contribute 16 percent of the total emission reduction. bThe VOC estimates consist of the sum of the HAP estimates and the non-HAP VOC estimates. cAs discussed in section III.B.3 of the preamble, the EPA has deferred the final decision regarding control of medium-sized storage vessels at existing sources. Therefore, the emission reductions for storage vessels shown above, and consequently for the total, may be slightly overstated. Table 2.--National CO and NOx Emissions Impacts in the Fifth Year ------------------------------------------------------------------------ Increase in CO Increase in Emission points emissionsa (Mg/ NOx emissionsa yr) (Mg/yr) ------------------------------------------------------------------------ Equipment leaks......................... 0 0 Process ventsb.......................... 1,600 16,000 Storage vessels......................... 0 0 Wastewater collection and treatment operationsc............................ 100 800 Transfer loading operationsb............ d d ------------------------------- Total............................... 1,700 17,000 ------------------------------------------------------------------------ aEmissions of these criteria pollutants are caused by operation of control devices. bEmissions result from the combustion of natural gas along with the organic HAP emission streams in incinerators and flares. cEmissions result from the combustion of various fossil fuels to generate steam for use in a steam stripper. dEmissions are less than 5 Mg/yr. Table 3.--National Energy Impacts In The Fifth Year -------------------------------------------------------------------------------------------------------------------------------------------------------- Increase in electricity Increase in Natural gas Increase in steam Totald consumptiona consumptionb consumptionb,c ------------------------- Emission points ------------------------------------------------------------------------------ 106 kw-hr/ 103 BOE/yr TJ yr 103 BOE/yr 109 Btu/yr 103 BOE/yr 109 Btu/yr 103 BOE/yr -------------------------------------------------------------------------------------------------------------------------------------------------------- Equipment leaks................................. 0 0 0 0 0 0 0 0 Process vents................................... 260 430 6,900 1,100 0 0 1,500 9,600 Storage vesselse................................ 16 26 0 0 0 0 26 170 Wastewater collection and treatment............. 13 21 3 0.5 3,000 500 520 3,300 Transfer loading operations..................... f 0 45 7 0 0 7 45 ------------------------------------------------------------------------------------------------------- Totale...................................... 290 480 6,900 1,100 3,000 500 2,100 13,000 -------------------------------------------------------------------------------------------------------------------------------------------------------- aConversion to BOE assumed a power plant heat rate of 10,000 Btu/kw-hr, heating value for oil of 144,400 Btu/gal, and 42 gal/bbl. bConversion to BOE assumed a heating value for oil of 144,400 Btu/gal and 42 gal/bbl. cSteam use is calculated by multiplying the total volume of wastewater (lpm) from new and existing sources by the steam to feed ratio in the steam stripper (0.04) and assuming the steam stripper operates 351 days per year. It is assumed that the latent heat of the steam is 1131 Btu/lb and the boiler has an efficiency of 80 percent (Memorandum from Kristine Pelt, Radian Corporation, to Mary Tom Kissell, EPA/SDB, ``Secondary Environmental Impact Factors used in the Framework for Steam Stirpping Wastewater.'' February 1, 1994.) dDue to rounding, column totals may be slightly different. eAs discussed in section III.B.3 of this preamble, the EPA has deferred the final decision regarding control of medium-sized storage vessels at existing sources. Therefore, the energy impacts for storage vessels, and consequently for the total, may be slightly overstated. fElectricity usage is less than 1 * 10\6\ kw-hr/yr. Table 4.--National Control Cost Impacts In The Fifth Year ---------------------------------------------------------------------------------------------------------------- Total Average HAP Average VOC capital Total annual cost cost Emission points costs (106 costs (106 $/ effectivenessa effectivenessa $) yr) ($/Mg HAP) ($/Mg VOC) ---------------------------------------------------------------------------------------------------------------- Equipment leaks...................................... 120 (0.26) (5) (4) Process vents........................................ 100 86 290 170 Storage vesselsb..................................... 77 20 2,800 2,800 Wastewater collection and treatment operations....... 140 50 490 130 Transfer loading operations.......................... 12 5 10,000 10,000 ---------------------------------------------------------- Totalb, c........................................ 450 160 350 170 ---------------------------------------------------------------------------------------------------------------- aAverage cost-effectiveness values are determined by dividing total annual costs by total annual emissions reduction. bAs discussed in section III.B.3 of the preamble, the EPA has deferred the final decision regarding control of medium-sized storage vessels at existing sources. Therefore, the cost impacts associated with storage vessels, and consequently the total, may be slightly overstated. cExcept for the Total Capital Costs column, the total figures do not include an element for equipment leaks because the analysis of equipment leak requirements indicated a cost savings. Table 5.--Summary of Characteristics of Emission Points Subject to Proposed Subpart G ------------------------------------------------------------------------ Emission point For existing sources For new sources ------------------------------------------------------------------------ Process vents.......... Vent streams from Vent streams from continuous (non-batch) continuous (non- process that:. batch) process that: (1) contain 50 ppmw HAP's and eq>50 ppmw HAP's and (2) have a flowrate 0.005 scmm and 0.005 scmm and (3) have a cost (3) have a cost effectiveness $2,000/Mg eq>$11,000/Mg. Storage tanksa......... Storage vessels having: Storage vessels (1) a capacity 75 m\3\ and <151 (1) a capacity 38 m\3\ and <151 pressure 13.1 kilopascal; or pressure 13.1 kilopascal; eq>151 m\3\ with a or vapor pressure 5.2 kilopascal eq>151 m\3\ with a vapor pressure 0.7 kilopascal. Transfer operations.... Transfer racks that Same as existing load 0.65 source. million liters of HAP- containing liquids with a vapor pressure 10.3 kilopascal. Wastewater treatment Wastewater streams Wastewater streams operationsb. that: that: (1) contain a total (1) have a flowrate VOHAP concentration of 10 lpm and table 9 HAP's of 10,000 ppmw; or concentration of (2) have a flowrate 10 lpm and thn-eq>1,000 ppmw; or contain a total VOHAP (2) have a flowrate concentration of table 0.02 lpm 9 HAP's of 1,000 ppmw concentration of any table 8 HAP 10 ppmw. ------------------------------------------------------------------------ aAs discussed in section III.B.3 of the preamble, the EPA has deferred the final decision regarding control of medium-sized storage vessels (i.e., 76 m\3\ and <151 m\3\). The applicability criteria specified in this table represent option 1 in table 6. bWastewater treatment operations are exempt if the total source mass HAP flow rate from all of these streams, determined prior to exposure to the atmosphere and prior to treatment, is less than 1 metric ton per year. Table 6.--Control Alternatives for Existing Sources Subject to Subpart Ga ---------------------------------------------------------------------------------------------------------------- Emission Percent Kind of emission point Control reduction emission Cost $1,000/ Avg. $/Mg Inc. $/Mg option Mg/yr reduction yr ---------------------------------------------------------------------------------------------------------------- Process ventsb.................... 1 235,000 93 55,000 234 ........... 2 236,000 93 58,000 245 1,800 3 238,000 94 62,000 260 2,500 4 239,000 94 66,000 276 3,900 5 241,000 95 97,000 404 23,000 Wastewaterc....................... 0 0 0 0 0 ........... 1 68,400 79 29,200 430 430 2 69,100 80 32,100 470 4,300 3 69,600 81 39,100 560 13,000 4 73,100 85 123,000 1,700 24,000 Transferd......................... 1 360 65 3,100 8,700 ........... 2 420 77 6,500 15,000 54,000 Storage: Smalle................... 1 0 0 0 0 ........... 2 380 95 22,000 58,000 58,000 Storage: Mediumf,g................ 1 370 72 2,400 6,600 ........... 2 450 88 6,400 14,200 48,000 Storage: Largeh................... 1 2,000 19 5,300 2,600 ........... 2 5,100 48 10,300 2,000 1,600 3 8,900 84 25,300 2,800 3,900 4 9,000 84 27,100 3,000 122,000 Totali: Floorg................ ........... 238,000 68 66,000 280 ........... Selected optiong............ ........... 312,000 89 107,000 340 550 Total controlg.............. ........... 324,000 92 282,000 870 14,600 ---------------------------------------------------------------------------------------------------------------- aThe impacts in this table are based on well-characterized chemical manufacturing processes and were estimated using the model emission point approach described in Section V of the proposal (57 FR 62621-62622). bProcess vent options are: 1TRE = $1,500/Mg 2TRE = $2,000/Mg 3TRE = $3,000/Mg 4TRE = $5,000/Mg 5Control of all process vents. cWastewater options are: 110 lpm and 1,000 ppm 25 lpm and 800 ppm 31 lpm and 500 ppm 4Control of all wastewater streams. dTransfer options are: 10.65 million liter and 10.3 kilopascal 2Control of all transfer racks. eSmall denotes storage vessels with capacity greater than or equal to 38 m3 (10,000 gal), but less than 75 m3 (20,000 gal). Option 1 is no control; and option 2 is control of all storage vessels. fMedium denotes storage vessels with capacity greater than or equal to 75 m3 (20,000 gal), but less than 151 m3 (40,000 gal). Option 1 is 1.9 psia; and option 2 is control of all storage vessels. gAs discussed in section III.B.3 of the preamble, the EPA has deferred the final decision regarding control of medium-sized storage vessels at existing sources. Therefore, figures for emission reduction and cost may be slightly overstated for storage vessels, and consequently for the totals. hLarge denotes storage vessels with capacity greater than or equal to 151 m3 (40,000 gal). Option 1 is 1.9 psia; option 2 is 0.75 psia; and option 3 is control of all storage vessels. iThese totals do not include control impacts for equipment leaks. The floor is represented by the first option for each emission point, except storage. Table 7.--Control Alternatives for New Sources Subject to Subpart Ga,b ---------------------------------------------------------------------------------------------------------------- Emission Percent Kind of emission point Control reduction emission Cost $1,000/ Avg. $/Mg Inc. $/Mg option Mg/yr reduction yr ---------------------------------------------------------------------------------------------------------------- Process Ventsc.................... 1 46,000 95 14,000 300 ........... 2 46,000 95 18,000 400 47,000 Wastewaterd....................... 1 10,300 63 10,000 975 ........... 2 13,500 82 12,800 948 860 3 13,900 85 23,500 1,690 28,000 Transfere......................... 1 68 65 590 8,700 ........... 2 80 77 1,200 15,000 54,000 Storage........................... 1 64 86 1,800 28,400 ........... Smallf............................ 2 71 95 4,100 58,100 336,000 Storage........................... 1 70 72 450 6,400 ........... Mediumg........................... 2 86 88 1,200 13,800 47,000 Storage........................... 1 970 48 1,600 1,600 ........... Largeh............................ 2 1,700 84 2,900 1,700 1,900 3 1,700 84 3,200 1,900 89,000 Totali: floor................. ........... 57,500 86 28,400 490 ........... Selected option............. ........... 61,400 92 32,500 530 1,100 Total control............... ........... 61,800 92 51,200 830 46,800 ---------------------------------------------------------------------------------------------------------------- aThe impacts in this table are based on well-characterized chemical manufacturing processes and were estimated using the model emission point approach described in Section V of the proposal (57 FR 62621--62622). bEstimated control impacts for fifth year after promulgation of the HON based on an assumed industry growth of 3.5 percent each year. cProcess vents options are: 1TRE = $11,000/Mg 2control of all process vents dWastewater options are: 110 ppmw 20.02 lpm and 10 ppmw 3control of all wastewater streams eNew and existing transfer options are the same. fSmall denotes storage vessels with capacity greater than or equal to 38 m\3\ (10,000 gal), but less than 75 m\3\ (20,000 gal). Option 1 is 1.9 psia; and option 2 is control of all storage vessels. gMedium denotes storage vessels with capacity greater than or equal to 75 m\3\ (20,000 gal), but less than 151 m\3\ (40,000 gal). Option 1 is 1.9 psia; and option 2 is control of all storage vessels. hLarge denotes storage vessels with capacity greater than or equal to 151 m\3\ (40,000 gal). Option 1 is 0.75 psia; option 2 is 0.10 psia; and option 2 is control of all storage vessels. iThese totals do not include control impacts for equipment leaks. The floor is represented by option 1 for each emission point. List of Subjects in 40 CFR Part 63 Environmental protection, Air pollution control, Hazardous substances, Incorporation by reference, Reporting and recordkeeping requirements. Dated: February 28, 1994. Carol M. Browner, The Administrator. For the reasons set out in the preamble, title 40, chapter I, part 63 of the Code of Federal Regulations is amended as follows: PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES 1. The authority citation for part 63 continues to read as follows: Authority: Sections 101, 112, 114, 116, and 301 of the Clean Air Act (42 U.S.C. 7401, et seq., as amended by Pub. L. 101-549, 104 Stat. 2399). 2. Section 63.14 is amended by adding paragraphs (b)(3) and (c) to read as follows: Sec. 63.14 Incorporation by reference. * * * * * (b) * * * (3) ASTM D2879-83, Standard Test Method for Vapor Pressure-- Temperature Relationship and Initial Decomposition Temperature of Liquids by Isoteniscope, IBR approved for Sec. 63.111 of subpart G of this part. (c) The materials listed below are available for purchase from the American Petroleum Institute (API), 1220 L Street, NW., Washington, DC 20005. (1) API Publication 2517, Evaporative Loss from External Floating- Roof Tanks, Third Edition, February 1989, IBR approved for Sec. 63.111 of subpart G of this part. (2) API Publication 2518, Evaporative Loss from Fixed-roof Tanks, Second Edition, October 1991, IBR approved for Sec. 63.150(g)(3)(i)(C) of subpart G of this part. 3. Part 63 is amended by adding subparts F, G, H, and I, and adding and reserving subparts J and K to read as follows: Subpart F--National Emission Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry Secs. 63.100 Applicability and designation of source. 63.101 Definitions. 63.102 General standards. 63.103 General compliance, reporting, and recordkeeping provisions. 63.104 Heat exchange system requirements. 63.105 Maintenance wastewater requirements. 63.106 Delegation of authority. Table 1 to Subpart F--Synthetic Organic Chemical Manufacturing Industry Chemicals Table 2 to Subpart F--Organic Hazardous Air Pollutants Table 3 to Subpart F--General Provisions Applicable to Supbarts F, G, and H Subpart G--National Emission Standards for Organic Hazardous Air Pollutants From Synthetic Organic Chemical Manufacturing Industry Process Vents, Storage Vessels, Transfer Operations, and Wastewater Secs. 63.110 Applicability. 63.111 Definitions. 63.112 Emission standard. 63.113 Process vent provisions--reference control technology. 63.114 Process vent provisions--monitoring requirements. 63.115 Process vent provisions--methods and procedures for process vent group determination. 63.116 Process vent provisions--performance test methods and procedures to determine compliance. 63.117 Process vent provisions--reporting and recordkeeping requirements for group and TRE determinations and performance tests. 63.118 Process vent provisions--periodic reporting and recordkeeping requirements. 63.119 Storage vessel provisions--reference control technology. 63.120 Storage vessel provisions--procedures to determine compliance. 63.121 Storage vessel provisions--alternative means of emission limitation. 63.122 Storage vessel provisions--reporting. 63.123 Storage vessel provisions--recordkeeping. 63.124 [Reserved] 63.125 [Reserved] 63.126 Transfer operations provisions--reference control technology. 63.127 Transfer operations provisions--monitoring requirements. 63.128 Transfer operations provisions--test methods and procedures. 63.129 Transfer operations provisions--reporting and recordkeeping for performance tests and notification of compliance status. 63.130 Transfer operations provisions--periodic reporting and recordkeeping. 63.131 Process wastewater provisions--flow diagrams and tables. 63.132 Process wastewater provisions--general. 63.133 Process wastewater provisions--wastewater tanks. 63.134 Process wastewater provisions--surface impoundments. 63.135 Process wastewater provisions--containers. 63.136 Process wastewater provisions--individual drain systems. 63.137 Process wastewater provisions--oil-water separators. 63.138 Process wastewater provisions--treatment processes. 63.139 Process wastewater provisions--control devices. 63.140 Process wastewater provisions--delay of repair. 63.141 [Reserved] 63.142 [Reserved] 63.143 Process wastewater provisions--inspections and monitoring of operations. 63.144 Process wastewater provisions--test methods and procedures for applicability and Group 1/Group 2 determination. 63.145 Process wastewater provisions--test methods and procedures to determine compliance. 63.146 Process wastewater provisions--reporting. 63.147 Process wastewater provisions--recordkeeping. 63.148 Leak inspection provisions. 63.149 [Reserved] 63.150 Emissions averaging provisions. 63.151 Initial notification and implementation plan. 63.152 General reporting and continuous records. Appendix to Subpart G--Tables and Figures Subpart H--National Emission Standards for Organic Hazardous Air Pollutants for Equipment Leaks Secs. 63.160 Applicability and designation of source. 63.161 Definitions. 63.162 Standards: General. 63.163 Standards: Pumps in light liquid service. 63.164 Standards: Compressors. 63.165 Standards: Pressure relief devices in gas/vapor service. 63.166 Standards: Sampling connection systems. 63.167 Standards: Open-ended valves or lines. 63.168 Standards: Valves in gas/vapor service and in light liquid service. 63.169 Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. 63.170 Standards: Surge control vessels and bottoms receivers. 63.171 Standards: Delay of repair. 63.172 Standards: Closed-vent systems and control devices. 63.173 Standards: Agitators in gas/vapor service and in light liquid service. 63.174 Standards: Connectors in gas/vapor service and in light liquid service. 63.175 Quality improvement program for valves. 63.176 Quality improvement program for pumps. 63.177 Alternative means of emission limitation: General. 63.178 Alternative means of emission limitation: Batch processes. 63.179 Alternative means of emission limitation: Enclosed-vented process units. 63.180 Test methods and procedures. 63.181 Recordkeeping requirements. 63.182 Reporting requirements. Table 1 to Subpart H--Batch Processes Subpart I--National Emission Standards for Organic Hazardous Air Pollutants for Certain Processes Subject to the Negotiated Regulation for Equipment Leaks 63.190 Applicability and designation of source. 63.191 Definitions. 63.192 Standard. 63.193 Delegation of authority. Subpart J--[Reserved] Subpart K--[Reserved] Subpart F--National Emission Standards for Organic Hazardous Air Pollutants from the Synthetic Organic Chemical Manufacturing Industry. Sec. 63.100 Applicability and designation of source. (a) This subpart provides applicability provisions, definitions, and other general provisions that are applicable to subparts G and H of this part. (b) Except as provided in paragraph (c) of this section, the provisions of subparts F, G, and H of this part apply to chemical manufacturing process units that meet all the criteria specified in paragraphs (b)(1), (b)(2), and (b)(3) of this section: (1) Manufacture as a primary product one or more of the chemicals listed in table 1 of this subpart; (2) Use as a reactant or manufacture as a product, by-product, or co-product, one or more of the organic hazardous air pollutants listed in table 2 of this subpart; and (3) Are located at a plant site that is a major source as defined in section 112(a) of the Act. (c) The owner or operator of a chemical manufacturing process unit that meets the criteria specified in paragraphs (b)(1) and (b)(3) of this section but does not use as a reactant or manufacture as a product, by-product, or co-product any organic hazardous air pollutant listed in table 2 of this subpart shall comply only with the requirements of Sec. 63.103(e) of this subpart. To comply with this subpart, such chemical manufacturing process units shall not be required to comply with the provisions of subpart A of this part. (d) The primary product of a chemical manufacturing process unit shall be determined according to the procedures specified in paragraphs (d)(1), (d)(2), and (d)(3) of this section. (1) If a chemical manufacturing process unit produces more than one intended chemical product, the product with the greatest annual design capacity on a mass basis determines the primary product of the process. (2) If a chemical manufacturing process unit has two or more products that have the same maximum annual design capacity on a mass basis and if one of those chemicals is listed in table 1 of this subpart, then the listed chemical is considered the primary product and the chemical manufacturing process unit is subject to this subpart. If more than one of the products is listed in table 1 of this subpart, then the owner or operator may designate as the primary product any of the listed chemicals and the chemical manufacturing process unit is subject to this subpart. (3) For chemical manufacturing process units that are designed and operated as flexible operation units, the primary product shall be determined for existing sources based on the expected utilization for the five years following April 22, 1994 and for new sources based on the expected utilization for the first five years after initial start- up. (i) If the predominant use of the flexible operation unit, as described in paragraphs (d)(3)(i)(A) and (d)(3)(i)(B) of this section, is to produce one or more chemicals listed in table 1 of this subpart, then the flexible operation unit shall be subject to the provisions of subparts F, G, and H of this part. (A) If the flexible operation unit produces one product for the greatest annual operating time, then that product shall represent the primary product of the flexible operation unit. (B) If the flexible operation unit produces multiple chemicals equally based on operating time, then the product with the greatest annual production on a mass basis shall represent the primary product of the flexible operation unit. (ii) The determination of applicability of this subpart to chemical manufacturing process units that are designed and operated as flexible operation units shall be reported in the Implementation Plan required by Sec. 63.151 (c), (d), and (e) of subpart G of this part or as part of an operating permit application. (e) The source to which this subpart applies is the collection of the process vents; storage vessels; transfer racks; wastewater and the associated treatment residuals; and pumps, compressors, agitators, pressure relief devices, sampling connection systems, open-ended valves or lines, valves, connectors, instrumentation systems, surge control vessels, and bottoms receivers that are associated with the chemical manufacturing process units that meet the criteria specified in paragraphs (b)(1) through (b)(3) of this section. (1) Subparts F and G of this part apply to emissions from process vents, storage vessels, transfer racks, and wastewater streams and associated treatment residuals within a source that is subject to this subpart. (2) Subparts F and H of this part apply to emissions from pumps, compressors, agitators, pressure relief devices, sampling connection systems, open-ended valves or lines, valves, connectors, instrumentation systems, surge control vessels, and bottoms receivers, within a source that is subject to this subpart. (f) The source does not include the emission points listed in paragraphs (f)(1) through (f)(9) of this section. This subpart does not require emission points that are not included in the source to comply with the provisions of subpart A of this part. (1) Vents from chemical manufacturing process units that are designed and operated as batch operations; (2) Stormwater from segregated sewers; (3) Water from fire-fighting and deluge systems in segregated sewers; (4) Spills; (5) Water from safety showers; (6) Vessels storing organic liquids that contain organic hazardous air pollutants only as impurities; (7) Loading racks, loading arms, or loading hoses that only transfer liquids containing organic hazardous air pollutants as impurities; (8) Loading racks, loading arms, or loading hoses that vapor balance during all loading operations; and (9) Equipment that is intended to operate in organic hazardous air pollutant service, as defined in Sec. 63.161 of subpart H of this part, for less than 300 hours during the calendar year. (g) The owner or operator shall follow the procedures specified in paragraphs (g)(1) and (g)(2) of this section to determine whether a storage vessel is part of the source to which this subpart applies. (1) Where a storage vessel is used exclusively by a chemical manufacturing process unit, the storage vessel shall be considered part of that chemical manufacturing process unit. (i) If the chemical manufacturing process unit is subject to this subpart according to the criteria specified in paragraph (b) of this section, then the storage vessel is part of the source to which this subpart applies. (ii) If the chemical manufacturing process unit is not subject to this subpart according to the criteria specified in paragraph (b) of this section, then the storage vessel is not part of the source to which this subpart applies. (2) If a storage vessel is not dedicated to a single chemical manufacturing process unit, then the applicability of subparts F and G of this part shall be determined according to the provisions in paragraphs (g)(2)(i) through (g)(2)(iv) of this section. (i) If a storage vessel is shared among chemical manufacturing process units and one of the process units has the predominant use, as determined by paragraph (g)(2)(i)(A) and (g)(2)(i)(B) of this section, then the storage vessel is part of that chemical manufacturing process unit. (A) If the greatest input into the storage vessel is from a chemical manufacturing process unit that is located on the same plant site, then that chemical manufacturing process unit has the predominant use. (B) If the greatest input into the storage vessel is provided from a chemical manufacturing process unit that is not located on the same plant site, then the predominant use is the chemical manufacturing process unit on the same plant site that receives the greatest amount of material from the storage vessel. (ii) If a storage vessel is shared among chemical manufacturing process units so that there is no single predominant use, and at least one of those chemical manufacturing process units is subject to this subpart, the storage vessel shall be considered to be part of the chemical manufacturing process unit that is subject to this subpart. If more than one chemical manufacturing process unit is subject to this subpart, the owner or operator may assign the storage vessel to any of the chemical manufacturing process units subject to this subpart. (iii) If the predominant use of a storage vessel varies from year to year, then the applicability of this subpart shall be determined based on the utilization that occurred during the year preceding April 22, 1994. This determination shall be reported in the Implementation Plan required by Sec. 63.151(c), (d), and (e) of subpart G of this part or as part of an operating permit application. (iv) If there is a change in the material stored in the storage vessel, the owner or operator shall reevaluate the applicability of this subpart to the vessel. (h) The owner or operator shall follow the procedures specified in paragraphs (h)(1) and (h)(2) of this section to determine whether the arms and hoses in a loading rack are part of the source to which this subpart applies. (1) Where a loading rack is used exclusively by a chemical manufacturing process unit, the loading rack shall be considered part of that specific chemical manufacturing process unit. (i) If the chemical manufacturing process unit is subject to this subpart according to the criteria specified in paragraph (b) of this section and the loading rack does not meet the criteria specified in paragraphs (f)(7) and (f)(8) of this section, then the loading rack is considered a transfer rack (as defined in Sec. 63.101 of this subpart) and is part of the source to which this subpart applies. (ii) If the chemical manufacturing process unit is not subject to this subpart according to the criteria specified in paragraph (b) of this section, then the loading rack is not considered a transfer rack (as defined in Sec. 63.101 of this subpart) and is not a part of the source to which this subpart applies. (2) If a loading rack is shared among chemical manufacturing process units, then the applicability of subparts F and G of this part shall be determined at each loading arm or loading hose according to the provisions in paragraphs (h)(2)(i) through (h)(2)(v) of this section. (i) Each loading arm or loading hose that is dedicated to the transfer of liquid organic hazardous air pollutants listed in table 2 of this subpart from a chemical manufacturing process unit to which this subpart applies is part of that chemical manufacturing process unit and is part of the source to which this subpart applies unless the loading arm or loading hose meets the criteria specified in paragraph (f)(7) or (f)(8) of this section. (ii) If a loading arm or loading hose is shared among chemical manufacturing process units, and one of the chemical manufacturing process units provides the greatest amount of the material that is loaded by the loading arm or loading hose, then the loading arm or loading hose is part of that chemical manufacturing process unit. (A) If the chemical manufacturing process unit is subject to this subpart according to the criteria specified in paragraph (b) of this section, then the loading arm or loading hose is part of the source to which this subpart applies unless the loading arm or loading hose meets the criteria specified in paragraph (f)(7) or (f)(8) of this section. (B) If the chemical manufacturing process unit is not subject to this subpart according to the criteria specified in paragraph (b) of this section, then the loading arm or loading hose is not part of the source to which this subpart applies. (iii) If a loading arm or loading hose is shared among chemical manufacturing process units so that there is no single predominant use as described in paragraph (h)(2)(ii) of this section and at least one of those chemical manufacturing process units is subject to this subpart, then the loading arm or hose is part of the chemical manufacturing process unit that is subject to this subpart. If more than one of the chemical manufacturing process units is subject to this subpart, the owner or operator may assign the loading arm or loading hose to any of the chemical manufacturing process units subject to this subpart. (iv) If the predominant use of a loading arm or loading hose varies from year to year, then the applicability of this subpart shall be determined based on the utilization that occurred during the year preceding April 22, 1994. This determination shall be reported in the Implementation Plan required by Sec. 63.151 (c), (d), and (e) of subpart G or as part of an operating permit application. (v) If there is a change in the material loaded at the loading arm or loading hose, the owner or operator shall reevaluate the applicability of this subpart to the loading arm or loading hose. (i) Except as provided in paragraph (i)(6) of this section, the owner or operator shall follow the procedures specified in paragraphs (i)(1) through (i)(5) of this section to determine whether the vent(s) from a distillation unit is part of the source to which this subpart applies. (1) If the greatest input to the distillation unit is from a chemical manufacturing process unit located on the same plant site, then the distillation unit shall be assigned to that chemical manufacturing process unit. (2) If the greatest input to the distillation unit is provided from a chemical manufacturing process unit that is not located on the same plant site, then the distillation unit shall be assigned to the chemical manufacturing process unit located at the same plant site that receives the greatest amount of material from the distillation unit. (3) If a distillation unit is shared among chemical manufacturing process units so that there is no single predominant use, as described in paragraphs (i)(1) and (i)(2) of this section, and at least one of those chemical manufacturing process units is subject to this subpart, the distillation unit shall be assigned to the chemical manufacturing process unit that is subject to this subpart. If more than one chemical manufacturing process unit is subject to this subpart, the owner or operator may assign the distillation unit to any of the chemical manufacturing process units subject to this rule. (4) If the chemical manufacturing process unit to which the distillation unit is assigned is subject to this subpart and the vent stream contains greater than 0.005 weight percent total organic hazardous air pollutants, then the vent(s) from the distillation unit is considered a process vent (as defined in Sec. 63.101 of this subpart) and is part of the source to which this subpart applies. (5) If the predominant use of a distillation unit varies from year to year, then the applicability of this subpart shall be determined based on the utilization that occurred during the year preceding April 22, 1994. This determination shall be included in the Implementation Plan required by Sec. 63.151 (c), (d), and (e) of subpart G of this part or as part of an operating permit application. (6) If the distillation unit is part of one of the chemical manufacturing process units listed in paragraphs (i)(6)(i) through (i)(6)(iii) of this section and the vent stream contains greater than 0.005 weight percent total organic hazardous air pollutants, then the vents from the distillation unit are considered process vents (as defined in Sec. 63.101 of this subpart) and are part of the source to which this subpart applies. (i) The Aromex unit that produces benzene, toluene, and xylene; (ii) The unit that produces hexane; or (iii) The unit that produces cyclohexane. (j) The provisions of subparts F, G, and H of this part do not apply to the processes specified in paragraphs (j)(1) through (j)(6) of this section. Subparts F, G, and H do not require processes specified in paragraphs (j)(1) through (j)(6) to comply with the provisions of subpart A of this part. (1) Research and development facilities, regardless of whether the facilities are located at the same plant site as a chemical manufacturing process unit that is subject to the provisions of subparts F, G, or H of this part. (2) Petroleum refining process units, regardless of whether the units supply feedstocks that include chemicals listed in table 1 of this subpart to chemical manufacturing process units that are subject to the provisions of subparts F, G, or H of this part. (3) Ethylene process units, regardless of whether the units supply feedstocks that include chemicals listed in table 1 of this subpart to chemical manufacturing process units that are subject to the provisions of subparts F, G, or H of this part. (4) Equipment that is located within a chemical manufacturing process unit that is subject to this subpart but does not contain organic hazardous air pollutants. (5) Chemical manufacturing process units that are located in coke by-product recovery plants. (6) Solvent reclamation, recovery, or recycling operations at hazardous waste TSDF facilities requiring a permit under 40 CFR part 270 that are separate entities and not part of a SOCMI chemical manufacturing process unit. (k) Except as provided in paragraphs (l) and (m) of this section, sources subject to subparts F, G, or H of this part are required to achieve compliance on or before the dates specified in paragraphs (k)(1), (k)(2), and (k)(3) of this section. (1) New sources that commence construction or reconstruction after December 31, 1992 shall be in compliance with subparts F, G, and H of this part upon initial start-up or April 22, 1994, whichever is later, as provided in Sec. 63.6(b) of subpart A of this part. (2) Existing sources shall be in compliance with subparts F and G of this part no later than 3 years after April 22, 1994, as provided in Sec. 63.6(c) of subpart A of this part, unless an extension has been granted by the Administrator as provided in Sec. 63.151(a)(6) of subpart G of this part or granted by the operating permit authority as provided in Sec. 63.6(i) of subpart A of this part. (3) Existing sources shall be in compliance with subpart H of this part no later than the dates specified in paragraphs (k)(3)(i) through (k)(3)(v) of this section. The group designation for each process unit is indicated in table 1 of this subpart. (i) Group I: October 24, 1994. (ii) Group II: January 23, 1995. (iii) Group III: April 24, 1995. (iv) Group IV: July 24, 1995. (v) Group V: October 23, 1995. (l)(1) If an additional chemical manufacturing process unit meeting the criteria specified in paragraph (b) of this section is added to a plant site that is a major source as defined in section 112(a) of the Act, the addition shall be subject to the requirements for a new source in subparts F, G, and H of this part if: (i) It is an addition that meets the definition of construction in Sec. 63.2 of subpart A of this part; (ii) Such construction commenced after December 31, 1992; and (iii) The addition has the potential to emit 10 tons per year or more of any HAP or 25 tons per year or more of any combination of HAP's, unless the Administrator establishes a lesser quantity. (2) If any change is made to a chemical manufacturing process unit subject to this subpart, the change shall be subject to the requirements of a new source in subparts F, G, and H of this part if: (i) It is a change that meets the definition of reconstruction in Sec. 63.2 of subpart A of this part; and (ii) Such reconstruction commenced after December 31, 1992. (3) If an additional chemical manufacturing process unit is added to a plant site or a change is made to a chemical manufacturing process unit and the addition or change is determined to be subject to the new source requirements according to paragraph (l)(1) or (l)(2) of this section: (i) The new or reconstructed source shall be in compliance with the new source requirements of subparts F, G, and H of this part upon initial start-up of the new or reconstructed source or by April 22, 1994, whichever is later; and (ii) The owner or operator of the new or reconstructed source shall comply with the reporting and recordkeeping requirements in subparts F, G, and H of this part that are applicable to new sources. The applicable reports include, but are not limited to: (A) The application for approval of construction or reconstruction which shall be submitted by the date specified in Sec. 63.151(b)(2)(ii) of subpart G of this part, or an Initial Notification as specified in Sec. 63.151(b)(2)(iii) of subpart G of this part; (B) The Implementation Plan and Implementation Plan Updates required by Sec. 63.151(c) and (j) of subpart G of this part, unless the information has been submitted in an operating permit application or amendment; (C) The Notification of Compliance Status as required by Sec. 63.152(b) of subpart G of this part for the new or reconstructed source; (D) Periodic Reports and Other Reports as required by Sec. 63.152(c) and (d) of subpart G of this part; (E) Reports required by Sec. 63.182 of subpart H of this part; and (F) Reports and notifications required by sections of subpart A of this part that are applicable to subparts F, G, and H of this part, as identified in table 3 of this subpart. (4) If an additional chemical manufacturing process unit is added to a plant site or if an emission point is added to an existing chemical manufacturing process unit or if another deliberate operational process change creating an additional Group 1 emission point(s) is made to an existing chemical manufacturing process unit, and if the addition or change is not subject to the new source requirements as determined according to paragraph (l)(1) or (l)(2) of this section, the requirements in paragraphs (l)(4)(i) through (l)(4)(iii) of this section shall apply. Examples of process changes include, but are not limited to, changes in production capacity, feedstock type, or catalyst type, or whenever there is replacement, removal, or addition of recovery equipment. For purposes of this paragraph and paragraph (m) of this section, process changes do not include: Process upsets, unintentional temporary process changes, and changes that are within the equipment configuration and operating conditions documented in the Notification of Compliance Status required by Sec. 63.152(b) of subpart G of this part. (i) The added emission point(s) and any emission point(s) within the added or changed chemical manufacturing process unit are subject to the requirements of subparts F, G, and H of this part for an existing source; (ii) The added emission point(s) and any emission point(s) within the added or changed chemical manufacturing process unit shall be in compliance with subparts F, G, and H of this part by the dates specified in paragraph (l)(4)(ii) (A) or (B) of this section, as applicable. (A) If a chemical manufacturing process unit is added to a plant site or an emission point(s) is added to an existing chemical manufacturing process unit, the added emission point(s) shall be in compliance upon initial start-up of the added chemical manufacturing process unit or emission point(s) or by 3 years after April 22, 1994, whichever is later. (B) If a deliberate operational process change to an existing chemical manufacturing process unit causes a Group 2 emission point to become a Group 1 emission point, the owner or operator shall be in compliance upon initial start-up or by 3 years after April 22, 1994 unless the owner or operator demonstrates to the Administrator that achieving compliance will take longer than making the change. If this demonstration is made to the Administrator's satisfaction, the owner or operator shall follow the procedures in paragraphs (m)(1) through (m)(3) of this section to establish a compliance date. (iii) The owner or operator of a chemical manufacturing process unit or emission point that is added to a plant site and is subject to the requirements for existing sources shall comply with the reporting and recordkeeping requirements of subparts F, G, and H of this part that are applicable to existing sources, including, but not limited to, the reports listed in paragraphs (l)(4)(iii) (A) through (E) of this section. A change to an existing chemical manufacturing process unit shall be subject to the reporting requirements for existing sources including, but not limited to, the reports listed in paragraphs (l)(4)(iii) (A) through (E) of this section if the change meets the criteria specified in Sec. 63.118 (g), (h), (i), or (j) of subpart G of this part for process vents or the criteria in Sec. 63.151 (i) or (j) of subpart G of this part for Implementation Plan Updates. The applicable reports include, but are not limited to: (A) The Implementation Plan Updates specified in Sec. 63.151 (i) and (j) of subpart G of this part, unless the information has been submitted in an operating permit application or amendment; (B) The Notification of Compliance Status as required by Sec. 63.152(b) of subpart G of this part for the emission points that were added or changed; (C) Periodic Reports and other reports as required by Sec. 63.152 (c) and (d) of subpart G of this part; (D) Reports required by Sec. 63.182 of subpart H of this part; and (E) Reports and notifications required by sections of subpart A of this part that are applicable to subparts F, G, and H of this part, as identified in table 3 of this subpart. (m) If a change that does not meet the criteria in paragraph (l)(4) of this section is made to a chemical manufacturing process unit subject to subparts F and G of this part, and the change causes a Group 2 emission point to become a Group 1 emission point (as defined in Sec. 63.111 of subpart G of this part), then the owner or operator shall comply with the requirements of subpart G of this part for the Group 1 emission point as expeditiously as practicable, but in no event later than 3 years after the emission point becomes Group 1. (1) The owner or operator shall submit to the Administrator for approval a compliance schedule, along with a justification for the schedule. (2) The compliance schedule shall be submitted with the Implementation Plan update required in Sec. 63.151(i)(2) of subpart G of this part for emission points included in an emissions average or Sec. 63.151(j)(1) of subpart G of this part for emission points not in an emissions average, unless the compliance schedule has been submitted in an operating permit application or amendment. (3) The Administrator shall approve the compliance schedule or request changes within 120 calendar days of receipt of the compliance schedule and justification. Sec. 63.101 Definitions. (a) The following terms as used in subparts F, G, and H of this part shall have the meaning given them in subpart A of this part: Act, actual emissions, Administrator, affected source, approved permit program, commenced, compliance date, construction, continuous monitoring system, continuous parameter monitoring system, effective date, emission standard, emissions averaging, EPA, equivalent emission limitation, existing source, Federally enforceable, fixed capital cost, hazardous air pollutant, lesser quantity, major source, malfunction, new source, owner or operator, performance evaluation, performance test, permit program, permitting authority, reconstruction, relevant standard, responsible official, run, standard conditions, State, and stationary source. (b) All other terms used in this subpart and subparts G and H of this part shall have the meaning given them in the Act and in this section. If the same term is defined in subpart A of this part and in this section, it shall have the meaning given in this section for purposes of subparts F, G, and H of this part. Air oxidation reactor means a device or vessel in which air, or a combination of air and oxygen, is used as an oxygen source in combination with one or more organic reactants to produce one or more organic compounds. Air oxidation reactor includes the product separator and any associated vacuum pump or steam jet. Batch operation means a noncontinuous operation in which a discrete quantity or batch of feed is charged into a chemical manufacturing process unit and distilled or reacted at one time. Batch operation includes noncontinuous operations in which the equipment is fed intermittently or discontinuously. Addition of raw material and withdrawal of product do not occur simultaneously in a batch operation. After each batch operation, the equipment is generally emptied before a fresh batch is started. Bottoms receiver means a tank that collects distillation bottoms before the stream is sent for storage or for further downstream processing. By-product means a chemical that is produced coincidentally during the production of another chemical. Chemical manufacturing process unit means the equipment assembled and connected by pipes or ducts to process raw materials and to manufacture an intended product. For the purpose of this subpart, chemical manufacturing process unit includes air oxidation reactors and their associated product separators and recovery devices; reactors and their associated product separators and recovery devices; distillation units and their associated distillate receivers and recovery devices; associated unit operations (as defined in this section); and any feed, intermediate and product storage vessels, product transfer racks, and connected ducts and piping. A chemical manufacturing process unit includes pumps, compressors, agitators, pressure relief devices, sampling connection systems, open-ended valves or lines, valves, connectors, instrumentation systems, and control devices or systems. A chemical manufacturing process unit is identified by its primary product. Control device means any equipment used for recovering or oxidizing organic hazardous air pollutant vapors. Such equipment includes, but is not limited to, absorbers, carbon adsorbers, condensers, incinerators, flares, boilers, and process heaters. For process vents (as defined in this section), recovery devices are not considered control devices. Co-product means a chemical that is produced during the production of another chemical. Distillate receiver means overhead receivers, overhead accumulators, reflux drums, and condenser(s) including ejector- condenser(s) associated with a distillation unit. Distillation unit means a device or vessel in which one or more feed streams are separated into two or more exit streams, each exit stream having component concentrations different from those in the feed stream(s). The separation is achieved by the redistribution of the components between the liquid and the vapor phases by vaporization and condensation as they approach equilibrium within the distillation unit. Distillation unit includes the distillate receiver, reboiler, and any associated vacuum pump or steam jet. Emission point means an individual process vent, storage vessel, transfer rack, wastewater stream, or equipment leak. Equipment leak means emissions of organic hazardous air pollutants from a pump, compressor, agitator, pressure relief device, sampling connection system, open-ended valve or line, valve, surge control vessel, bottoms receiver, or instrumentation system in organic hazardous air pollutant service as defined in Sec. 63.161 of subpart H of this part. Ethylene process or ethylene process unit means a chemical manufacturing process unit in which ethylene and/or propylene are produced by separation from petroleum refining process streams or by subjecting hydrocarbons to high temperatures in the presence of steam. The ethylene process unit includes the separation of ethylene and/or propylene from associated streams such as a C4 product, pyrolysis gasoline, and pyrolysis fuel oil. The ethylene process does not include the manufacture of SOCMI chemicals such as the production of butadiene from the C4 stream and aromatics from pyrolysis gasoline. Flexible operation unit means a chemical manufacturing process unit that manufactures different chemical products periodically by alternating raw materials or operating conditions. These units are also referred to as campaign plants or blocked operations. Heat exchange system means any cooling tower system or once-through cooling water system (e.g., river or pond water). A heat exchange system can include more than one heat exchanger and can include an entire recirculating or once-through cooling system. Impurity means a substance that is produced coincidentally with the primary product, or is present in a raw material. An impurity does not serve a useful purpose in the production or use of the primary product and is not isolated. Initial start-up means the first time a new or reconstructed source begins production, or, for equipment added or changed as described in Sec. 63.100 (l) or (m) of this subpart, the first time the equipment is put into operation. Initial start-up does not include operation solely for testing equipment. For purposes of subpart G of this part, initial start-up does not include subsequent start-ups (as defined in this section) of chemical manufacturing process units following malfunctions or shutdowns or following changes in product for flexible operation units or following recharging of equipment in batch operation. For purposes of subpart H of this part, initial start-up does not include subsequent start-ups (as defined in Sec. 63.161 of subpart H of this part) of process units (as defined in Sec. 63.161 of subpart H of this part) following malfunctions or process unit shutdowns. Loading rack means a single system used to fill tank trucks and railcars at a single geographic site. Loading equipment and operations that are physically separate (i.e, do not share common piping, valves, and other equipment) are considered to be separate loading racks. Maintenance wastewater means wastewater generated by the draining of process fluid from components in the chemical manufacturing process unit into an individual drain system prior to or during maintenance activities. Maintenance wastewater can be generated during planned and unplanned shutdowns and during periods not associated with a shutdown. Examples of activities that can generate maintenance wastewaters include descaling of heat exchanger tubing bundles, cleaning of distillation column traps, draining of low legs and high point bleeds, draining of pumps into an individual drain system, and draining of portions of the chemical manufacturing process unit for repair. Operating permit means a permit required by 40 CFR part 70 or 71. Organic hazardous air pollutant or organic HAP means one of the chemicals listed in table 2 of this subpart. Petroleum refining process, also referred to as a petroleum refining process unit, means a process that for the purpose of producing transportation fuels (such as gasoline and diesel fuels), heating fuels (such as fuel gas, distillate, and residual fuel oils), or lubricants separates petroleum or separates, cracks, or reforms unfinished derivatives. Examples of such units include, but are not limited to, alkylation units, catalytic hydrotreating, catalytic hydrorefining, catalytic hydrocracking, catalytic reforming, catalytic cracking, crude distillation, and thermal processes. Plant site means all contiguous or adjoining property that is under common control, including properties that are separated only by a road or other public right-of-way. Common control includes properties that are owned, leased, or operated by the same entity, parent entity, subsidiary, or any combination thereof. Process vent means a gas stream containing greater than 0.005 weight percent total organic hazardous air pollutants that is continuously discharged during operation of the unit from an air oxidation reactor, other reactor, or distillation unit (as defined in this section) within a chemical manufacturing process unit that meets all applicability criteria specified in Sec. 63.100(b)(1) through (b)(3) of this subpart. Process vents include vents from distillate receivers, product separators, and ejector-condensers. Process vents include gas streams that are either discharged directly to the atmosphere or are discharged to the atmosphere after diversion through a product recovery device. Process vents exclude relief valve discharges and leaks from equipment regulated under subpart H of this part. Process wastewater means wastewater which, during manufacturing or processing, comes into direct contact with or results from the production or use of any raw material, intermediate product, finished product, by-product, or waste product. Examples are product tank drawdown or feed tank drawdown; water formed during a chemical reaction or used as a reactant; water used to wash impurities from organic products or reactants; water used to cool or quench organic vapor streams through direct contact; and condensed steam from jet ejector systems pulling vacuum on vessels containing organics. Product means a compound or chemical which is manufactured as the intended product of the chemical manufacturing process unit. By- products, isolated intermediates, impurities, wastes, and trace contaminants are not considered products. Product separator means phase separators, flash drums, knock-out drums, decanters, degassers, and condenser(s) including ejector- condenser(s) associated with a reactor or an air oxidation reactor. Reactor means a device or vessel in which one or more chemicals or reactants, other than air, are combined or decomposed in such a way that their molecular structures are altered and one or more new organic compounds are formed. Reactor includes the product separator and any associated vacuum pump or steam jet. Recovery device means an individual unit of equipment capable of and used for the purpose of recovering chemicals for use, reuse, or sale. Recovery devices include, but are not limited to, absorbers, carbon adsorbers, and condensers. Research and development facility means laboratory and pilot plant operations whose primary purpose is to conduct research and development into new processes and products, where the operations are under the close supervision of technically trained personnel, and is not engaged in the manufacture of products for commercial sale, except in a de minimis manner. Shutdown means the cessation of operation of a chemical manufacturing process unit or a reactor, air oxidation reactor, distillation unit, or the emptying and degassing of a storage vessel for purposes including, but not limited to, periodic maintenance, replacement of equipment, or repair. Shutdown does not include the routine rinsing or washing of equipment in batch operation between batches. Source means the collection of emission points to which this subpart applies as determined by the criteria in Sec. 63.100 of this subpart. For purposes of subparts F, G, and H of this part, the term affected source as used in subpart A of this part has the same meaning as the term source defined here. Start-up means the setting into operation of a chemical manufacturing process unit for the purpose of production. Start-up does not include operation solely for testing equipment. Start-up does not include the recharging of equipment in batch operation. Start-up does not include changes in product for flexible operation units. Start-up, shutdown, and malfunction plan means the plan required under Sec. 63.6(e)(3) of subpart A of this part. This plan details the procedures for operation and maintenance of the source during periods of start-up, shutdown, and malfunction. Storage vessel means a tank or other vessel that is used to store organic liquids that contain one or more of the organic HAP's listed in table 2 of this subpart and that has been assigned, according to the procedures in Sec. 63.100(g) of this subpart, to a chemical manufacturing process unit that is subject to this subpart. Storage vessel does not include: (1) Vessels permanently attached to motor vehicles such as trucks, railcars, barges, or ships; (2) Pressure vessels designed to operate in excess of 204.9 kilopascals and without emissions to the atmosphere; (3) Vessels with capacities smaller than 38 cubic meters; (4) Vessels storing organic liquids that contain organic hazardous air pollutants only as impurities; (5) Bottoms receiver tanks; (6) Surge control vessels; or (7) Wastewater storage tanks. Wastewater storage tanks are covered under the wastewater provisions. Surge control vessel means feed drums, recycle drums, and intermediate vessels. Surge control vessels serve several purposes including equalization of load, mixing, recycle, and emergency supply. Transfer operation means the loading, into a tank truck or railcar, of organic liquids that contain one or more of the organic hazardous air pollutants listed in table 2 of this subpart from a transfer rack (as defined in this section). Transfer operations do not include loading at an operating pressure greater than 204.9 kilopascals. Transfer rack means the collection of loading arms and loading hoses, at a single loading rack, that are assigned to a chemical manufacturing process unit subject to this subpart according to the procedures specified in Sec. 63.100(h) of this subpart and are used to fill tank trucks and railcars with organic liquids that contain one or more of the organic hazardous air pollutants listed in table 2 of this subpart. Transfer rack includes the associated pumps, meters, shutoff valves, relief valves, and other piping and valves. Transfer rack does not include: (1) Racks, arms, or hoses that only transfer liquids containing organic hazardous air pollutants as impurities; (2) Racks, arms, or hoses that vapor balance during all loading operations; or (3) Racks transferring organic liquids that contain organic hazardous air pollutants only as impurities. Unit operation means one or more pieces of process equipment used to make a single change to the physical or chemical characteristics of one or more process streams. Unit operations include, but are not limited to, reactors, distillation columns, extraction columns, absorbers, decanters, dryers, condensers, and filtration equipment. Vapor balancing system means a piping system that is designed to collect organic HAP vapors displaced from tank trucks or railcars during loading; and to route the collected organic HAP vapors to the storage vessel from which the liquid being loaded originated, or to compress collected organic HAP vapors and commingle with the raw feed of a chemical manufacturing process unit. Wastewater means organic hazardous air pollutant-containing water, raw material, intermediate, product, by- product, co-product, or waste material that exits equipment in a chemical manufacturing process unit that meets all of the criteria specified in Sec. 63.100(b)(1) through (b)(3) of this subpart; and either: (1) Contains a total volatile organic hazardous air pollutant concentration of at least 5 parts per million by weight and has a flow rate of 0.02 liter per minute or greater; or (2) Contains a total volatile organic hazardous air pollutant concentration of at least 10,000 parts per million by weight at any flow rate. Wastewater includes process wastewater and maintenance wastewater. Sec. 63.102 General standards. (a) Owners and operators of sources subject to this subpart shall comply with the requirements of subparts G and H of this part. (1) The provisions set forth in subparts F and G of this part shall apply at all times except during periods of start-up, malfunction, and shutdown (as defined in Sec. 63.101 of this subpart). However, if a start-up, shutdown, or malfunction of one portion of a chemical manufacturing process unit does not affect the ability of a particular emission point to comply with the specific provisions to which it is subject, then that emission point shall still be required to comply with the applicable provisions of subparts F and G during the start-up, shutdown, or malfunction. For example, if there is an overpressure in the reactor area, a storage vessel in the chemical manufacturing process unit would still be required to be controlled in accordance with Sec. 63.119 of subpart G of this part. Similarly, the degassing of a storage vessel would not affect the ability of a process vent to meet the requirements of Sec. 63.113 of subpart G of this part. (2) The provisions set forth in subpart H of this part shall apply at all times except during periods of start-up, malfunction, and process unit shutdown (as defined in Sec. 63.161 of subpart H of this part). (b) If, in the judgment of the Administrator, an alternative means of emission limitation will achieve a reduction in organic HAP emissions at least equivalent to the reduction in organic HAP emissions from that source achieved under any design, equipment, work practice, or operational standards in subpart G or H of this part, the Administrator will publish in the Federal Register a notice permitting the use of the alternative means for purposes of compliance with that requirement. (1) The notice may condition the permission on requirements related to the operation and maintenance of the alternative means. (2) Any notice under paragraph (b) of this section shall be published only after public notice and an opportunity for a hearing. (3) Any person seeking permission to use an alternative means of compliance under this section shall collect, verify, and submit to the Administrator information showing that the alternative means achieves equivalent emission reductions. (c) Each owner or operator of a source subject to this subpart shall obtain a permit under 40 CFR part 70 or part 71 from the appropriate permitting authority. (1) If EPA has approved a State operating permit program under 40 CFR part 71, the permit shall be obtained from the State authority. If the State operating permit program has not been approved, the source shall apply to the EPA regional office pursuant to 40 CFR part 70. (2) If an operating permit application has not been submitted by the dates specified in Sec. 63.151(c) of subpart G of this part, the owner or operator shall submit an Implementation Plan as specified in Sec. 63.151 (c), (d), and (e) of subpart G of this part. (d) The requirements in subparts F, G, and H of this part are Federally enforceable under section 112 of the Act on and after the dates specified in Sec. 63.100(k) of this subpart. Sec. 63.103 General compliance, reporting, and recordkeeping provisions. (a) Table 3 of this subpart specifies the provisions of subpart A that apply and those that do not apply to owners and operators of sources subject to subparts F, G, and H of this part. (b) Initial performance tests and initial compliance determinations shall be required only as specified in subparts G and H of this part. (1) Performance tests and compliance determinations shall be conducted according to the schedule and procedures in Sec. 63.7(a) of subpart A of this part and the applicable sections of subparts G and H of this part. (2) The owner or operator shall notify the Administrator of the intention to conduct a performance test at least 30 calendar days before the performance test is scheduled to allow the Administrator the opportunity to have an observer present during the test. (3) Performance tests shall be conducted according to the provisions of Sec. 63.7(e) of subpart A of this part, except that performance tests shall be conducted at maximum representative operating conditions for the process. During the performance test, an owner or operator may operate the control or recovery device at maximum or minimum representative operating conditions for monitored control or recovery device parameters, whichever results in lower emission reduction. (4) Data shall be reduced in accordance with the EPA-approved methods specified in the applicable subpart or, if other test methods are used, the data and methods shall be validated according to the protocol in Method 301 of appendix A of this part. (5) Performance tests may be waived with approval of the Administrator as specified in Sec. 63.7(h)(2) of subpart A of this part. Owners or operators of sources subject to subparts F, G, and H of this part who apply for a waiver of a performance test shall submit the application by the dates specified in paragraph (b)(5)(i) of this section rather than the dates specified in Sec. 63.7(h)(3) of subpart A of this part. (i) If a request is made for an extension of compliance under Sec. 63.151(a)(6) of subpart G or Sec. 63.6(i) of subpart A of this part, the application for a waiver of an initial performance test shall accompany the information required for the request for an extension of compliance. If no extension of compliance is requested, the application for a waiver of an initial performance test shall be submitted no later than 90 calendar days before the Notification of Compliance Status required in Sec. 63.152(b) of subpart G of this part is due to be submitted. (ii) Any application for a waiver of a performance test shall include information justifying the owner or operator's request for a waiver, such as the technical or economic infeasibility, or the impracticality, of the source performing the required test. (c) Each owner or operator of a source subject to subparts F, G, and H of this part shall keep copies of all applicable reports and records required by subparts F, G, and H of this part for at least 5 years; except that, if subparts G or H require records to be maintained for a time period different than 5 years, those records shall be maintained for the time specified in subpart G or H of this part. (1) All applicable records shall be maintained in such a manner that they can be readily accessed. The most recent 2 years of records shall be retained on site at the source or shall be accessible from a central location by computer. The remaining 3 years of records may be retained offsite. Records may be maintained in hard copy or computer- readable form including, but not limited to, on paper, microfilm, computer, floppy disk, magnetic tape, or microfiche. (2) The owner or operator subject to subparts F, G, and H of this part shall keep the records specified in this paragraph, as well as records specified in subparts G and H. (i) Records of the occurrence and duration of each start-up, shutdown, and malfunction of operation of a chemical manufacturing process unit subject to subparts F, G, or H of this part. (ii) Records of the occurrence and duration of each malfunction of air pollution control equipment or continuous monitoring systems used to comply with subpart F, G, or H of this part. (iii) For each start-up, shutdown, and malfunction, records that the procedures specified in the source's start-up, shutdown, and malfunction plan were followed, and documentation of actions taken that are not consistent with the plan. For example, if a start-up, shutdown, and malfunction plan includes procedures for routing a control device to a backup control device (e.g., the incinerator for a halogenated stream could be routed to a flare during periods when the primary control device is out of service), records must be kept of whether the plan was followed. (iv) For continuous monitoring systems used to comply with subpart G, records documenting the completion of calibration checks and maintenance of continuous monitoring systems that are specified in the manufacturer's instructions. (3) Records of start-up, shutdown and malfunction and continuous monitoring system calibration and maintenance are not required if they pertain solely to Group 2 emission points, as defined in Sec. 63.111 of subpart G of this part, that are not included in an emissions average. (d) All reports required under subparts F, G, and H of this part shall be sent to the Administrator at the addresses listed in Sec. 63.13 of subpart A of this part, except that requests for permission to use an alternative means of compliance as provided for in Sec. 63.102(b) of this subpart and application for approval of a nominal efficiency as provided for in Sec. 63.150 (i)(1) through (i)(6) of subpart G of this part shall be submitted to the Director of the EPA Office of Air Quality Planning and Standards rather than to the Administrator or delegated authority. (1) Wherever subpart A specifies ``postmark'' dates, submittals may be sent by methods other than the U.S. Mail (e.g., by fax or courier). (i) Submittals sent by U.S. Mail shall be postmarked on or before the specified date. (ii) Submittals sent by other methods shall be received by the Administrator on or before the specified date. (2) If acceptable to both the Administrator and the owner or operator of a source, reports may be submitted on electronic media. (e) Information, data, and analyses used to determine that a chemical manufacturing process unit does not use as a reactant or manufacture as a product any organic hazardous air pollutant shall be recorded. Examples of information that could document this include, but are not limited to, records of chemicals purchased for the process, analyses of process stream composition, engineering calculations, or process knowledge. Sec. 63.104 Heat exchange system requirements. (a) Owners and operators of sources subject to subpart G of this part shall comply with the requirements specified in paragraphs (b) and (c) of this section. (b) For each heat exchange system that cools process equipment or a process fluid and that is part of a chemical manufacturing process unit that is subject to the provisions of this subpart, the owner or operator shall comply with the requirements of paragraphs (b)(1) through (b)(4) of this section, except as provided in paragraph (c) of this section. (1) The cooling water shall be monitored monthly for the first 6 months and quarterly thereafter to detect leaks. (i) The cooling water shall be monitored for total HAP, total VOC, or speciated HAP's. (A) For recirculating heat exchange systems (cooling tower systems), speciated HAP's or total HAP's includes all HAP's listed in table 2 of this subpart, except for benzotrichloride (98077), bis(chloromethyl)ether (542881), maleic anhydride (108316), and methyl isocyanate (624839). (B) For once-through heat exchange systems, speciated HAP's or total HAP's includes all HAP's listed in table 9 of subpart G of this part. (C) If monitoring for speciated HAP's, only HAP's that are present in the process fluid in concentrations greater than 5 percent by weight are required to be measured in the cooling water. (ii) The concentration in the cooling water shall be determined using any EPA-approved method listed in 40 CFR part 136 as long as the method is sensitive to concentrations as low as 1 ppm and the same method is used for both entrance and exit samples. Alternative methods may be used upon approval by the Administrator. (iii) The samples shall be taken at the entrance and exit of each heat exchange system. (A) For recirculating heat exchange systems, the entrance and exit are the points at which the cooling water enters the cooling tower after cooling the process fluid and exits the cooling tower prior to cooling the process fluid. (B) For once-through heat exchange systems, the entrance and exit are the points where the cooling water enters and exits the plant site. (iv) A minimum of three sets of samples shall be taken of the cooling water at the entrance and exit of the system, for a total of six samples. The average inlet and outlet concentrations shall then be calculated. (v) A leak is detected if a statistically significant difference in concentration of at least 1 part per million at the 95 percent confidence level is observed. (2) If a leak is detected, the owner or operator shall comply with the requirements in paragraphs (b)(2)(i) and (b)(2)(ii) of this section, except as provided in paragraph (b)(3) of this section. (i) The leak shall be repaired as soon as practicable but not later than 45 calendar days after the owner or operator receives results of monitoring tests that indicate that a leak is present. Repair of a leak can include such activities as repairing a leaking heat exchanger or rerouting the waste from a steam jet ejector. (ii) Once the leak has been repaired, the owner or operator must test the heat exchange system using the procedures described in paragraph (b)(1) of this section to ensure that the leak has been repaired. (3) Delay of repair of heat exchange systems for which leaks have been detected is allowed if either of the conditions in paragraph (b)(3)(i) or (b)(3)(ii) of this section are met. (i) If the owner or operator can demonstrate that a shutdown would cause greater emissions than the emissions from the leaking heat exchange system until the next planned shutdown, a shutdown is not required. Repair of this equipment shall occur before the end of the next shutdown. (ii) If the equipment is isolated from the process and does not remain in HAP service. (4) If an owner or operator invokes the delay of repair provisions for a heat exchange system, the following information shall be submitted in the next semi-annual Periodic Report required by Sec. 63.152(c) of subpart G of this part. If the leak remains unrepaired, the information shall also be submitted in each subsequent periodic report, until repair of the leak is reported. (i) The owner or operator shall report the presence of the leak and the date that the leak was detected. (ii) The owner or operator shall report whether or not the leak has been repaired. (iii) The owner or operator shall report the reason(s) for delay of repair. If delay of repair is invoked due to the reasons described in paragraph (b)(3)(i) of this section, documentation of emissions estimates must also be submitted. (iv) If the leak remains unrepaired, the owner or operator shall report the expected date of repair. (v) If the leak is repaired, the owner or operator shall report the date of successful repair of the leak. (c) An owner or operator is not required to meet the requirements in paragraphs (b)(1) and (b)(2) of this section if either of the conditions in paragraph (c)(1) or (c)(2) of this section are met. (1) The heat exchange system is operated with the minimum pressure on the cooling water side at least 35 kilopascals greater than the maximum pressure on the process side. (2) The once-through heat exchange system currently has an NPDES permit with an allowable discharge limit of less than 1 ppm. Sec. 63.105 Maintenance wastewater requirements. (a) Each owner or operator of a source subject to this subpart shall comply with the requirements of paragraphs (b) through (e) of this section for maintenance wastewaters containing those organic HAP's listed in table 2 of this subpart. (b) The owner or operator shall prepare a description of maintenance procedures for management of wastewaters generated from the emptying and purging of equipment in the process during temporary shutdowns for inspections, maintenance, and repair (i.e., a maintenance-turnaround) and during periods which are not shutdowns (i.e., routine maintenance). The descriptions shall: (1) Specify the process equipment or maintenance tasks that are anticipated to create wastewater during maintenance activities. (2) Specify the procedures that will be followed to properly manage the wastewater and control organic HAP emissions to the atmosphere; and (3) Specify the procedures to be followed when clearing materials from process equipment. (c) The owner or operator shall modify and update the information required by paragraph (b) of this section as needed following each maintenance procedure based on the actions taken and the wastewaters generated in the preceding maintenance procedure. (d) The owner or operator shall implement the procedures described in paragraphs (b) and (c) of this section as part of the start-up, shutdown, and malfunction plan required under Sec. 63.6(e)(3) of subpart A of this part. (e) The owner or operator shall maintain a record of the information required by paragraphs (b) and (c) of this section as part of the start-up, shutdown, and malfunction plan required under Sec. 63.6(e)(3) of subpart A of this part. Sec. 63.106 Delegation of authority. (a) In delegating implementation and enforcement authority to a State under section 112(d) of the Act, the authorities contained in paragraph (b) of this section shall be retained by the Administrator and not transferred to a State. (b) Authorities which will not be delegated to States: Sec. 63.102(b) of this subpart, Sec. 63.150(i)(1) through (i)(4) of subpart G of this part, and Sec. 63.177 of subpart H of this part. Table 1 to Subpart F--Synthetic Organic Chemical Manufacturing Industry Chemicals ------------------------------------------------------------------------ Chemical namea CAS No.b Group ------------------------------------------------------------------------ Acenaphthene....................................... 83329 V Acetal............................................. 105577 V Acetaldehyde....................................... 75070 II Acetaldol.......................................... 107891 II Acetamide.......................................... 60355 II Acetanilide........................................ 103844 II Acetic acid........................................ 64197 II Acetic anhydride................................... 108247 II Acetoacetanilide................................... 102012 III Acetone............................................ 67641 I Acetone cyanohydrin................................ 75865 V Acetonitrile....................................... 75058 I Acetophenone....................................... 98862 I Acrolein........................................... 107028 IV Acrylamide......................................... 79061 I Acrylic acid....................................... 79107 IV Acrylonitrile...................................... 107131 I Adiponitrile....................................... 111693 I Alizarin........................................... 72480 V Alkyl anthraquinones............................... 008 V Allyl alcohol...................................... 107186 I Allyl chloride..................................... 107051 IV Allyl cyanide...................................... 109751 IV Aminophenol sulfonic acid.......................... 0010 V Aminophenol (p-)................................... 123308 I Aniline............................................ 62533 I Aniline hydrochloride.............................. 142041 III Anisidine (o-)..................................... 90040 II Anthracene......................................... 120127 V Anthraquinone...................................... 84651 III Azobenzene......................................... 103333 I Benzaldehyde....................................... 100527 III Benzene............................................ 71432 I Benzenedisulfonic acid............................. 98486 I Benzenesulfonic acid............................... 98113 I Benzil............................................. 134816 III Benzilic acid...................................... 76937 III Benzoic acid....................................... 65850 III Benzoin............................................ 119539 III Benzonitrile....................................... 100470 III Benzophenone....................................... 119619 I Benzotrichloride................................... 98077 III Benzoyl chloride................................... 98884 III Benzyl acetate..................................... 140114 III Benzyl alcohol..................................... 100516 III Benzyl benzoate.................................... 120514 III Benzyl chloride.................................... 100447 III Benzyl dichloride.................................. 98873 III Biphenyl........................................... 92524 I Bisphenol A........................................ 80057 III Bis(Chloromethyl) Ether............................ 542881 I Bromobenzene....................................... 108861 I Bromoform.......................................... 75252 V Bromonaphthalene................................... 27497514 IV Butadiene (1,3-)................................... 106990 II Butanediol (1,4-).................................. 110634 I Butyl acrylate (n-)................................ 141322 V Butylene glycol (1,3-)............................. 107880 II Butyrolacetone..................................... 96480 I Caprolactam........................................ 105602 II Carbaryl........................................... 63252 V Carbazole.......................................... 86748 V Carbon disulfide................................... 75150 IV Carbon tetrabromide................................ 558134 II Carbon tetrachloride............................... 56235 I Carbon tetrafluoride............................... 75730 II Chloral............................................ 75876 II Chloroacetic acid.................................. 79118 II Chloroacetophenone (2-)............................ 532274 I Chloroaniline (p-)................................. 106478 II Chlorobenzene...................................... 108907 I 2-Chloro-1,3-butadiene (Chloroprene)............... 126998 II Chlorodifluoroethane............................... 25497294 V Chlorodifluoromethane.............................. 75456 I Chloroform......................................... 67663 I Chloronaphthalene.................................. 25586430 IV Chloronitrobenzene 121733 I (m-). Chloronitrobenzene 88733 I (o-). Chloronitrobenzene 100005 I (p-). Chlorophenol (m-).................................. 108430 II Chlorophenol (o-).................................. 95578 II Chlorophenol (p-).................................. 106489 II Chlorotoluene (m-)................................. 108418 III Chlorotoluene (o-)................................. 95498 III Chlorotoluene (p-)................................. 106434 III Chlorotrifluoromethane............................. 75729 II Chrysene........................................... 218019 V Cresol and cresylic acid (m-)...................... 108394 III Cresol and cresylic acid (o-)...................... 95487 III Cresol and cresylic acid (p-)...................... 106445 III Cresols and cresylic acids (mixed)................. 1319773 III Cumene............................................. 98828 I Cumene hydroperoxide............................... 80159 I Cyanoacetic acid................................... 372098 II Cyclohexane........................................ 110827 I Cyclohexanol....................................... 108930 I Cyclohexanone...................................... 108941 I Cyclohexylamine.................................... 108918 III Cyclooctadienes.................................... 29965977 II Decahydronaphthalene............................... 91178 IV Diacetoxy-2-Butene (1,4-).......................... 0012 V Diaminophenol hydrochloride........................ 137097 V Dibromomethane..................................... 74953 V Dichloroaniline (mixed isomers).................... 27134276 I Dichlorobenzene (p-)............................... 106467 I Dichlorobenzene (m-)............................... 541731 I Dichlorobenzene (o-)............................... 95501 I Dichlorobenzidine 91941 I (3,3'-). Dichlorodifluoromethane............................ 75718 I Dichloroethane (1,2-) (Ethylenedichloride) (EDC)... 107062 I Dichloroethyl ether (bis(2-chloroethyl)ether)...... 111444 I Dichloroethylene (1,2-)............................ 540590 II Dichlorophenol (2,4-).............................. 120832 III Dichloropropene (1,3-)............................. 542756 II Dichlorotetrafluoro- 1320372 V ethane. Dichloro-1-butene (3,4-)........................... 760236 II Dichloro-2-butene (1,4-)........................... 764410 V Diethanolamine (2,2'-Iminodiethanol)............... 111422 I Diethyl sulfate.................................... 64675 II Diethylamine....................................... 109897 IV Diethylaniline (2,6-).............................. 579668 V Diethylene glycol.................................. 111466 I Diethylene glycol dibutyl ether.................... 112732 I Diethylene glycol diethyl ether.................... 112367 I Diethylene glycol dimethyl ether................... 111966 I Diethylene glycol monobutyl ether acetate.......... 124174 I Diethylene glycol monobutyl ether.................. 112345 I Diethylene glycol monoethyl ether acetate.......... 112152 I Diethylene glycol monoethyl ether.................. 111900 I Diethylene glycol monohexyl ether.................. 112594 V Diethylene glycol monomethyl ether acetate......... 629389 V Diethylene glycol monomethyl ether................. 111773 I Dihydroxybenzoic acid (Resorcylic acid)............ 27138574 V Dimethylbenzidine 119937 II (3,3'-). Dimethyl ether..................................... 115106 IV Dimethylformamide (N,N-)........................... 68122 II Dimethylhydrazine 57147 II (1,1-). Dimethyl sulfate................................... 77781 I Dimethyl terephthalate............................. 120616 II Dimethylamine...................................... 124403 IV Dimethylaminoethanol (2-).......................... 108010 I Dimethylaniline (N,N).............................. 121697 III Dinitrobenzenes (NOS)c............................. 25154545 I Dinitrophenol (2,4-)............................... 51285 III Dinitrotoluene (2,4-).............................. 121142 III Dioxane (1,4-) (1,4-Diethyleneoxide)............... 1239 11I Dioxolane (1,3-)................................... 646060 I Diphenyl methane................................... 101815 I Diphenyl oxide..................................... 101848 I Diphenyl thiourea.................................. 102089 III Diphenylamine...................................... 122394 III Dipropylene glycol................................. 110985 I Di-o-tolyguanidine................................. 97392 III Dodecandedioic acid................................ 693232 I Dodecyl benzene (branched)......................... 123013 V Dodecyl phenol (branched).......................... 121158585 V Dodecylaniline..................................... 28675174 V Dodecylbenzene (n-)................................ 121013 I Dodecylphenol...................................... 27193868 III Epichlorohydrin (1-chloro-2,3-epoxypropane)........ 106898 I Ethanolamine....................................... 141435 I Ethyl acrylate..................................... 140885 II Ethylbenzene....................................... 100414 I Ethyl chloride (Chloroethane)...................... 75003 IV Ethyl chloroacetate................................ 105395 II Ethylamine......................................... 75047 V Ethylaniline (N-).................................. 103695 III Ethylaniline (o-).................................. 578541 III Ethylcellulose..................................... 9004573 V Ethylcyanoacetate.................................. 105566 V Ethylene carbonate................................. 96491 I Ethylene dibromide (Dibromoethane)................. 106934 I Ethylene glycol.................................... 107211 I Ethylene glycol diacetate.......................... 111557 I Ethylene glycol dibutyl ether...................... 112481 V Ethylene glycol diethyl ether 629141 I (1,2-diethoxyethane). Ethylene glycol 110714 I dimethyl ether Ethylene glycol monoacetate........................ 542596 V Ethylene glycol monobutyl ether 112072 I acetate. Ethylene glycol monobutyl ether.................... 111762 I Ethylene glycol monoethyl ether 111159 I acetate. Ethylene glycol monoethyl ether.................... 110805 I Ethylene glycol monohexyl ether.................... 112254 V Ethylene glycol monomethyl ether acetate........... 110496 I Ethylene glycol monomethyl ether................... 109864 I Ethylene glycol monooctyl ether.................... 002 V Ethylene glycol monophenyl ether................... 122996 I Ethylene glycol monopropyl ether................... 2807309 I Ethylene oxide..................................... 75218 I Ethylenediamine.................................... 107153 II Ethylenediamine tetraacetic acid................... 60004 V Ethylenimine (Aziridine)........................... 151564 II Ethylhexyl acrylate (2-isomer)..................... 103117 II Fluoranthene....................................... 206440 V Formaldehyde....................................... 50000 I Formamide.......................................... 75127 II Formic acid........................................ 64186 II Fumaric acid....................................... 110178 I Glutaraldehyde..................................... 111308 IV Glyceraldehyde..................................... 367475 V Glycerol........................................... 56815 II Glycerol tri- (polyoxypro- pylene)ether............ 25791962 II Glycine............................................ 56406 II Glyoxal............................................ 107222 II Hexachlorobenzene.................................. 118741 II Hexachlorobutadiene................................ 87683 II Hexachloroethane................................... 67721 II Hexadiene (1,4-)................................... 592450 II Hexamethylene- 100970 I tetramine. Hexane............................................. 110543 V Hexanetriol (1,2,6-)............................... 106694 IV Hydroquinone....................................... 123319 I Hydroxyadipaldehyde................................ 141311 V Isobutyl acrylate.................................. 106638 V Isobutylene........................................ 115117 V Isophorone......................................... 78591 IV Isophorone nitrile................................. 0017 V Isophthalic acid................................... 121915 III Isopropylphenol.................................... 25168063 III Linear alkylbenzene................................ ____d I Maleic anhydride................................... 108316 I Maleic hydrazide................................... 123331 I Malic acid......................................... 6915157 I Metanilic acid..................................... 121471 I Methacrylic acid................................... 79414 V Methanol........................................... 67561 IV Methionine......................................... 63683 I Methyl acetate..................................... 79209 IV Methyl acrylate.................................... 96333 V Methyl bromide (Bromomethane)...................... 74839 IV Methyl chloride (Chloromethane).................... 74873 IV Methyl ethyl ketone (2-butanone)................... 78933 V Methyl formate..................................... 107313 II Methyl hydrazine................................... 60344 IV Methyl isobutyl carbinol........................... 108112 IV Methyl isobutyl ketone (Hexone).................... 108101 IV Methyl isocyanate.................................. 624839 IV Methyl mercaptan................................... 74931 IV Methyl methacrylate................................ 80626 IV Methyl phenyl carbinol............................. 98851 II Methyl tert-butyl ether............................ 1634044 V Methylamine........................................ 74895 IV Methylaniline (N-)................................. 100618 III Methylcyclohexane.................................. 108872 III Methylcyclohexanol................................. 25639423 V Methylcyclohexanone................................ 1331222 III Methylene chloride (Dichloromethane)............... 75092 I Methylene dianiline (4,4'-isomer).................. 101779 I Methylene diphenyl diisocyanate (4,4'-) (MDI)...... 101688 III Methylionones (a-)................................. 79696 V Methylpentynol..................................... 77758 V Methylstyrene (a-)................................. 98839 I Naphthalene........................................ 91203 IV Naphthalene sulfonic acid (a-)..................... 85472 IV Naphthalene sulfonic acid (b-)..................... 120183 IV Naphthol (a-)...................................... 90153 IV Naphthol (b-)...................................... 135193 IV Naphtholsulfonic acid (1-)......................... 567180 V Naphthylamine sulfonic acid (1,4-)................. 84866 V Naphthylamine sulfonic acid (2,1-)................. 81163 V Naphthylamine (1-)................................. 134327 V Naphthylamine (2-)................................. 91598 V Nitroaniline (m-).................................. 99092 II Nitroaniline (o-).................................. 88744 I Nitroanisole (o-).................................. 91236 III Nitroanisole (p-).................................. 100174 III Nitrobenzene....................................... 98953 I Nitronaphthalene (1-).............................. 86577 IV Nitrophenol (p-)................................... 100027 III Nitrophenol (o-)................................... 88755 III Nitropropane (2-).................................. 79469 II Nitrotoluene (all isomers)......................... 1321126 III Nitrotoluene (o-).................................. 88722 III Nitrotoluene (m-).................................. 99081 III Nitrotoluene (p-).................................. 99990 III Nitroxylene........................................ 25168041 V Nonylbenzene (branched)............................ 1081772 V Nonylphenol........................................ 25154523 V Octene-1........................................... 111660 I Octylphenol........................................ 27193288 III Paraformaldehyde................................... 30525894 I Paraldehyde........................................ 123637 II Pentachlorophenol.................................. 87865 III Pentaerythritol.................................... 115775 I Peracetic acid..................................... 79210 II Perchloromethyl mercaptan.......................... 594423 IV Phenanthrene....................................... 85018 V Phenetidine (p-)................................... 156434 III Phenol............................................. 108952 III Phenolphthalein.................................... 77098 III Phenolsulfonic acids (all isomers)................. 1333397 III Phenyl anthranilic acid (all isomers).............. 91407 III Phenylenediamine (p-).............................. 106503 I Phloroglucinol..................................... 108736 III Phosgene........................................... 75445 IV Phthalic acid...................................... 88993 III Phthalic anhydride................................. 85449 III Phthalimide........................................ 85416 III Phthalonitrile..................................... 91156 III Picoline (b-)...................................... 108996 II Piperazine......................................... 110850 I Polyethylene glycol................................ 25322683 V Polypropylene glycol............................... 25322694 V Propiolactone (beta-).............................. 57578 I Propionaldehyde.................................... 123386 IV Propionic acid..................................... 79094 I Propylene carbonate................................ 108327 V Propylene dichloride (1,2-dichloropropane)......... 78875 IV Propylene glycol................................... 57556 I Propylene glycol monomethyl ether.................. 107982 I Propylene oxide.................................... 75569 I Pyrene............................................. 129000 V Pyridine........................................... 110861 II p-tert-Butyl toluene............................... 98511 III Quinone............................................ 106514 III Resorcinol......................................... 108463 I Salicylic acid..................................... 69727 III Sodium methoxide................................... 124414 IV Sodium phenate..................................... 139026 III Stilbene........................................... 588590 III Styrene............................................ 100425 I Succinic acid...................................... 110156 I Succinonitrile..................................... 110612 I Sulfanilic acid.................................... 121573 III Sulfolane.......................................... 126330 II Tartaric acid...................................... 526830 I Terephthalic acid.................................. 100210 II Tetrabromophthalic anhydride....................... 632791 III Tetrachlorobenzene (1,2,4,5-)...................... 95943 I Tetrachloroethane (1,1,2,2-)....................... 79345 II Tetrachloroethylene (Perchloroethylene)............ 127184 I Tetrachlorophthalic- 117088 III anhydride. Tetraethyl lead.................................... 78002 IV Tetraethylene glycol............................... 112607 I Tetraethylene- 112572 V pentamine. Tetrahydrofuran.................................... 109999 I Tetrahydronapthalene............................... 119642 IV Tetrahydrophthalic anhydride....................... 85438 II Tetramethylene- 110601 II diamine. Tetramethylethylenediamine......................... 110189 V Tetramethyllead.................................... 75741 V Thiocarbanilide.................................... 102089 V Toluene............................................ 108883 I Toluene 2,4 diamine................................ 95807 II Toluene 2,4 diisocyanate........................... 584849 II Toluene diisocyanates (mixture).................... 26471625 II Toluene sulfonic acids............................. 104154 III Toluenesulfonyl chloride........................... 98599 III Toluidine (o-)..................................... 95534 II Trichloroaniline- 634935 III (2,4,6-). Trichlorobenzene (1,2,3-).......................... 87616 V Trichlorobenzene (1,2,4-).......................... 120821 I Trichloroethane 71556 II (1,1,1-) Trichloroethane (1,1,2-) (Vinyl trichloride)....... 79005 II Trichloroethylene.................................. 79016 I Trichlorofluoromethane............................. 75694 I Trichlorophenol 95954 I (2,4,5-). (1,1,2-) Trichloro 76131 I (1,2,2-) trifluoroethane. Triethanolamine.................................... 102716 I Triethylamine...................................... 121448 IV Triethylene glycol................................. 112276 I Triethylene glycol 112492 I dimethyl ether. Triethylene glycol monoethyl ether................. 112505 V Triethylene glycol monomethyl ether................ 112356 I Trimethylamine..................................... 75503 IV Trimethylcyclohexanol.............................. 933482 IV Trimethylcyclo- 2408379 IV hexanone. Trimethylcyclo- 34216347 V hexylamine. Trimethylolpropane................................. 77996 I Trimethylpentane (2,2,4-).......................... 540841 V Tripropylene glycol................................ 24800440 V Vinyl acetate...................................... 108054 II Vinyl chloride (Chloroethylene).................... 75014 I Vinyl toluene...................................... 25013154 III Vinylcyclohexene (4-).............................. 100403 II Vinylidene chloride 75354 II (1,1-dichloroethylene). Vinyl(N-)-pyrrolidone(2-).......................... 88120 V Xanthates.......................................... 140896 V Xylene sulfonic acid............................... 25321419 III Xylenes (NOS)c..................................... 1330207 I Xylene (m-)........................................ 108383 I Xylene (o-)........................................ 95476 I Xylene (p-)........................................ 106423 I Xylenols (Mixed)................................... 1300716 V Xylidene........................................... 1300738 III ------------------------------------------------------------------------ aIsomer means all structural arrangements for the same number of atoms of each element and does not mean salts, esters, or derivatives. bCAS Number = Chemical Abstract Service number. cNOS = not otherwise specified. dNo CAS number assigned. Table 2. to Subpart F--Organic Hazardous Air Pollutants ------------------------------------------------------------------------ Chemical name a,b CAS No.c ------------------------------------------------------------------------ Acetaldehyde................................................ 75070 Acetamide................................................... 60355 Acetonitrile................................................ 75058 Acetophenone................................................ 98862 Acrolein.................................................... 107028 Acrylamide.................................................. 79061 Acrylic acid................................................ 79107 Acrylonitrile............................................... 107131 Allyl chloride.............................................. 107051 Aniline..................................................... 62533 Anisidine (o-).............................................. 90040 Benzene..................................................... 71432 Benzotrichloride............................................ 98077 Benzyl chloride............................................. 100447 Biphenyl.................................................... 92524 Bis(chloromethyl)ether...................................... 542881 Bromoform................................................... 75252 Butadiene (1,3-)............................................ 106990 Caprolactam................................................. 105602 Carbon disulfide............................................ 75150 Carbon tetrachloride........................................ 56235 Chloroacetic acid........................................... 79118 Chloroacetophenone (2-)..................................... 532274 Chlorobenzene............................................... 108907 2-Chloro-1,3-butadiene (Chloroprene)........................ 126998 Chloroform.................................................. 67663 Cresols and cresylic acids (mixed).......................... 1319773 Cresol and cresylic acid (o-)............................... 95487 Cresol and cresylic acid (m-)............................... 108394 Cresol and cresylic acid (p-)............................... 106445 Cumene...................................................... 98828 Dichlorobenzene (p-)........................................ 106467 Dichlorobenzidine (3,3'-)................................... 91941 Dichloroethane (1,2-) (Ethylene dichloride) (EDC)........... 107062 Dichloroethylether 111444 (Bis(2-chloroethyl) ether). Dichloropropene (1,3-)...................................... 542756 Diethanolamine (2,2'- 111422 Iminodiethanol). Dimethylaniline (N,N-)...................................... 121697 Diethyl sulfate............................................. 64675 Dimethylbenzidine (3,3'-)................................... 119937 Dimethylformamide (N,N-).................................... 68122 Dimethylhydrazine (1,1-).................................... 57147 Dimethyl phthalate.......................................... 131113 Dimethyl sulfate............................................ 77781 Dinitrophenol (2,4-)........................................ 51285 Dinitrotoluene (2,4-)....................................... 121142 Dioxane (1,4-)(1,4- 123911 Diethyleneoxide). 1,2-Diphenylhydrazine....................................... 122667 Epichlorohydrin (1-Chloro-2,3-epoxypropane)................. 106898 Ethyl acrylate.............................................. 140885 Ethylbenzene................................................ 100414 Ethyl chloride (Chloroethane)............................... 75003 Ethylene dibromide 106934 (Dibromoethane). Ethylene glycol............................................. 107211 Ethylene oxide.............................................. 75218 Ethylidene dichloride 75343 (1,1-Dichloroethane). Formaldehyde................................................ 50000 Glycol ethersd Hexachlorobenzene........................................... 118741 Hexachlorobutadiene......................................... 87683 Hexachloroethane............................................ 67721 Hexane...................................................... 100543 Hydroquinone................................................ 123319 Isophorone.................................................. 78591 Maleic anhydride............................................ 108316 Methanol.................................................... 67561 Methyl bromide (Bromomethane)............................... 74839 Methyl chloride (Chloromethane)............................. 74873 Methyl ethyl ketone 78933 (2-Butanone). Methyl hydrazine............................................ 60344 Methyl isobutyl ketone (Hexone)............................. 108101 Methyl isocyanate........................................... 624839 Methyl methacrylate......................................... 80626 Methyl tert-butyl ether..................................... 1634044 Methylene chloride (Dichloromethane)........................ 75092 Methylene diphenyl diisocyanate (4,4'-) (MDI)............... 101688 Methylenedianiline (4,4'-).................................. 101779 Naphthalene................................................. 91203 Nitrobenzene................................................ 98953 Nitrophenol (p-)............................................ 100027 Nitropropane (2-)........................................... 79469 Phenol...................................................... 108952 Phenylenediamine (p-)....................................... 106503 Phosgene.................................................... 75445 Phthalic anhydride.......................................... 85449 Polycyclic organic mattere Propiolactone (beta-)....................................... 57578 Propionaldehyde............................................. 123386 Propylene dichloride 78875 (1,2-Dichloropropane). Propylene oxide............................................. 75569 Quinone..................................................... 106514 Styrene..................................................... 100425 Tetrachloroethane (1,1,2,2-)................................ 79345 Tetrachloroethylene (Perchloroethylene)..................... 127184 Toluene..................................................... 108883 Toluene diamine (2,4-)...................................... 95807 Toluene diisocyanate (2,4-)................................. 584849 Toluidine (o-).............................................. 95534 Trichlorobenzene (1,2,4-)................................... 120821 Trichloroethane (1,1,1-) (Methyl chloroform)................ 71556 Trichloroethane (1,1,2-) (Vinyl trichloride)................ 79005 Trichloroethylene........................................... 79016 Trichlorophenol (2,4,5-).................................... 95954 Triethylamine............................................... 121448 Trimethylpentane (2,2,4-)................................... 540841 Vinyl acetate............................................... 108054 Vinyl chloride (chloroethylene)............................. 75014 Vinylidene chloride 75354 (1,1-Dichloroethylene). Xylenes (NOS)............................................... 1330207 Xylene (m-)................................................. 108383 Xylene (o-)................................................. 95476 Xylene (p-)................................................. 106423 ------------------------------------------------------------------------ aFor all listings above containing the word ``Compounds'' and for glycol ethers, the following applies: Unless otherwise specified, these listings are defined as including any unique chemical substance that contains the named chemical (i.e., antimony, arsenic) as part of that chemical's infrastructure. bIsomer means all structural arrangements for the same number of atoms of each element and does not mean salts, esters, or derivatives. cCAS Number=Chemical Abstract Service number. dIncludes mono- and di- ethers of ethylene glycol, diethylene glycol, and triethylene glycol R-(OCH2CH2)n-OR' where: n=1, 2, or 3; R=alkyl or aryl groups; and R'=R, H, or groups which, when removed, yield glycol ethers with the structure: R-(OCH2CH2)n-OH Polymers are excluded from the glycol category. eincludes organic compounds with more than one benzene ring, and which have a boiling point greater than or equal to 100 deg.C. Table 3 to Subpart F--General Provisions Applicability to subparts F, G, and Ha ---------------------------------------------------------------------------------------------------------------- Applies to Reference Subparts F, G, Comment and H ---------------------------------------------------------------------------------------------------------------- 63.1(a)(1)........................................ Yes............. Overlap clarified in Sec. 63.101, Sec. 63.111, Sec. 63.161. 63.1(a)(2)........................................ Yes. 63.1(a)(3)........................................ Yes............. Sec. 63.110 and Sec. 63.160(b) of subparts G and H identify which standards are overridden. 63.1(a)(4)........................................ No.............. Subpart F specifies applicability of each paragraph in subpart A to subparts F, G, and H. 63.1(a)(5)-(a)(9)................................. No. 63.1(a)(10)....................................... No.............. Subparts F, G, and H specify calendar or operating day. 63.1(a)(11)....................................... No.............. Subpart F Sec. 63.103(d) specifies acceptable methods for submitting reportsa. 63.1(a)(12)-(a)(14)............................... Yes. 63.1(b)(1)........................................ No.............. Subpart F specifies applicability. 63.1(b)(2)........................................ Yes. 63.1(b)(3)........................................ No. 63.1(c)(1)........................................ No.............. Subpart F specifies applicability. 63.1(c)(2)........................................ No.............. Area sources are not subject to subparts F, G, and H. 63.1(c)(3)........................................ No. 63.1(c)(4)........................................ Yes. 63.1(c)(5)........................................ No.............. Subparts G and H specify applicable notification requirements. 63.1(d)........................................... No. 63.1(e)........................................... No.............. Subparts F, G, and H established before permit program. 63.2.............................................. Yes............. Subpart F Sec. 63.103 specifies those subpart A definitions that apply to the HON. Subpart F definition of ``source'' is equivalent to subpart A definition of ``affected source''. 63.3.............................................. No.............. Units of measure are spelled out in subparts F, G, and H. 63.4(a)(1)-(a)(3)................................. Yes. 63.4(a)(4)........................................ No. 63.4(a)(5)........................................ Yes. 63.4(b)........................................... Yes. 63.4(c)........................................... Yes. 63.5(a)(1)........................................ Yes............. Except replace term ``source'' and ``stationary source'' in Sec. 63.5(a)(1) of subpart A with ``affected source''. 63.5(a)(2)........................................ Yes. 63.5(b)(1)........................................ Yes. 63.5(b)(2)........................................ No. 63.5(b)(3)........................................ Yes. 63.5(b)(4)........................................ Yes............. Except the cross reference to Sec. 63.9(b) is changed to Sec. 63.9(b) (4) and (5). Subpart F overrides Sec. 63.9 (b)(2) and (b)(3). 63.5(b)(5)........................................ Yes. 63.5(b)(6)........................................ Yes. 63.5(c)........................................... No. 63.5(d)(1)(i)..................................... No.............. Subpart G Sec. 63.151(b) (2)(ii) and (2)(iii) specify the applicability and timing of this submittal for sources subject to subpart G. 63.5(d)(1)(ii).................................... Yes............. Except that for affected sources subject to subpart G instead of the information in Sec. 63.5(d)(1)(ii)(H), submit the implementation plan information specified in Sec. 63.151(e). 63.5(d)(1)(iii)................................... No. Subpart G requires submittal of the notification of compliance status in Sec. 63.152(b). 63.5(d)(2)........................................ No. 63.5(d)(3)........................................ Yes............. Except Sec. 63.5(d)(3)(ii) does not apply to subpart G. 63.5(d)(4)........................................ Yes. 63.5(e)........................................... Yes. 63.5(f)(1)........................................ Yes. 63.5(f)(2)........................................ Yes. 63.5(f)(3)........................................ Yes............. Except the cross-reference to Sec. 63.5(d)(1) is changed to Sec. 63.151(b)(ii) of subpart G, and the cross- reference to (b)(2) does not apply. 63.5(f)(4)........................................ Yes. 63.6(a)........................................... Yes. 63.6(b)(1)........................................ No.............. Subparts F and H specify compliance dates for sources subject to subparts F, G, and H. 63.6(b)(2)........................................ No. 63.6(b)(3)........................................ Yes. 63.6(b)(4)........................................ No.............. May apply when standards are proposed under section 112(f) of the Act. 63.6(b)(5)........................................ No.............. Subparts G and H include notification requirements. 63.6(b)(6)........................................ No. 63.6(b)(7)........................................ No. 63.6(c)(1)........................................ No.............. Subpart F specifies the compliance date. 63.6(c)(2)........................................ No. 63.6(c)(3)........................................ No. 63.6(c)(4)........................................ No. 63.6(c)(5)........................................ Yes. 63.6(d)........................................... No. 63.6(e)........................................... Yes............. Does not apply to Group 2 emission points unless they are included in an emissions averageb. 63.6(f)(1)........................................ No.............. Sec. 63.102(a) of subpart F specifies when the standards apply. 63.6(f)(2)(i)..................................... Yes. 63.6(f)(2)(ii).................................... Yes............. Sec. 63.151(c)(2) of subpart G specifies the use of monitoring data in determining compliance with subpart G. 63.6(f)(2)(iii) (A), (B), and (C)................. Yes. 63.6(f)(2)(iii)(D)................................ No. 63.6(f)(2)(iv).................................... Yes. 63.6(f)(2)(v)..................................... Yes. 63.6(f)(3)........................................ Yes. 63.6(g)........................................... No.............. Procedures specified in Sec. 63.102(b) of subpart F. 63.6(h)........................................... No. 63.6(i)(1)........................................ Yes. 63.6(i)(2)........................................ Yes. 63.6(i)(3)........................................ No.............. Sec. 63.151(a)(6) of subpart G specifies procedures. 63.6(i)(4)(i)(A).................................. Yes. 63.6(i)(4)(i)(B).................................. No.............. Dates are specified in Sec. 63.151(a)(6) of subpart G. 63.6(i)(4)(ii).................................... No. 63.6(i)(5)-(14)................................... Yes. 63.6(i)(15)....................................... No. 63.6(i)(16)....................................... Yes. 63.6(j)........................................... Yes. 63.7(a)(1)........................................ No.............. Subparts F, G, and H specify required testing and compliance demonstration procedures. 63.7(a)(2)........................................ No.............. Test results must be submitted in the notification of compliance status due 150 days after compliance date, as specified in Sec. 63.152(b) of subparts G and H. 63.7(a)(3)........................................ Yes. 63.7(b)........................................... No. 63.7(c)........................................... No. 63.7(d)........................................... Yes. 63.7(e)(1)........................................ Yes. 63.7(e)(2)........................................ Yes. 63.7(e)(3)........................................ No.............. Subparts F, G, and H specify test methods and procedures. 63.7(e)(4)........................................ Yes. 63.7(f)........................................... No.............. Subparts F, G, and H specify applicable methods and provide alternatives. 63.7(g)........................................... No.............. Performance test reporting specified in Sec. 63.152(b) of subparts G and H. 63.7(h)(1)........................................ Yes. 63.7(h)(2)........................................ Yes. 63.7(h)(3)........................................ No.............. Sec. 63.103(b)(5) of subpart F specifies provisions for requests to waive performance tests. 63.7(h)(4)........................................ No. 63.7(h)(5)........................................ Yes. 63.8(a)(1)........................................ Yes. 63.8(a)(2)........................................ No. 63.8(a)(3)........................................ No. 63.8(a)(4)........................................ Yes. 63.8(b)(1)........................................ Yes. 63.8(b)(2)........................................ No.............. Subparts G and H specify locations to conduct monitoring. 63.8(b)(3)........................................ Yes. 63.8(c)(1)(i)..................................... Yes. 63.8(c)(1)(ii).................................... No.............. Addressed by periodic reports in Sec. 63.152(c) of subpart G. 63.8(c)(1)(iii)................................... Yes. 63.8(c)(2)........................................ Yes. 63.8(c)(3)........................................ Yes. 63.8(c)(4)........................................ No.............. HON specifies monitoring frequency in Sec. 63.111 and Sec. 63.152(f) of subpart G. 63.8(c)(5)-(c)(8)................................. No. 63.8(d)........................................... No. 63.8(e)........................................... No. 63.8(f)(1)-(f)(3)................................. Yes. 63.8(f)(4)(i)..................................... No.............. Timeframe for submitting request specified in Sec. 63.152(g)(1) of subpart G. 63.8(f)(4)(ii).................................... Yes. 63.8(f)(4)(iii)................................... No. 63.8(f)(5)(i)..................................... Yes. 63.8(f)(5)(ii).................................... No. 63.8(f)(5)(iii)................................... Yes. 63.8(f)(6)........................................ No.............. Subparts G and H do not require CEM's. 63.8(g)........................................... No.............. Data reduction procedures specified in Sec. 63.152(f) of subpart G. 63.9(a)........................................... Yes. 63.9(b)(1)(i)..................................... No.............. Specified in Sec. 63.151(b)(2)(ii) of subpart G. 63.9(b)(1)(ii).................................... No. 63.9(b)(2)........................................ No.............. Initial notification provisions are specified in Sec. 63.151(b) of subpart G. 63.9(b)(3)........................................ No. 63.9(b)(4)........................................ Yes............. Except that the notification in Sec. 63.9(b)(4)(i) shall be submitted at the time specified in Sec. 63.151(b)(2)(ii) of subpart G. 63.9(b)(5).....