# Revisions and Confidentiality Determinations for Data Elements Under the Greenhouse Gas Reporting Rule > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2023-10047 ## Record - **Collection:** Federal Register - **Document type:** Proposed Rule - **Published:** May 22, 2023 - **Citation:** 88 FR 32852 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 98 [EPA-HQ-OAR-2019-0424; FRL-7230-03-OAR] RIN 2060-AU35 Revisions and Confidentiality Determinations for Data Elements Under the Greenhouse Gas Reporting Rule AGENCY: Environmental Protection Agency (EPA). ACTION: Supplemental notice of proposed rulemaking. SUMMARY: The EPA is issuing this supplemental proposal that would amend specific provisions in the Greenhouse Gas Reporting Rule to improve the quality and consistency of the rule by providing for the collection of improved data that would better inform and be relevant to a wide variety of Clean Air Act provisions that the EPA carries out. The EPA recently evaluated the requirements of the Greenhouse Gas Reporting Rule to identify areas of improvement, including updates to the existing calculation, recordkeeping, and reporting requirements, and requested information for collection of additional data to understand new source categories in a proposed rule (June 21, 2022). In this notification, the EPA is proposing additional amendments to the Greenhouse Gas Reporting Rule, including updates to the General Provisions to reflect revised global warming potentials, and is proposing to require reporting of greenhouse gas data from additional sectors—specifically energy consumption; coke calcining; ceramics production; calcium carbide production; and caprolactam, glyoxal, and glyoxylic acid production. The EPA is also proposing additional revisions that would improve implementation of the Greenhouse Gas Reporting Rule, such as updates to emissions calculation methodologies; revisions to reporting requirements to improve verification of reported data and the accuracy of the data collected; and other minor technical amendments, corrections, or clarifications. The EPA intends to consider the information received in response to this supplemental proposal prior to finalizing the amendments to the Greenhouse Gas Reporting Rule proposed on June 21, 2022. This action also proposes to establish and amend confidentiality determinations for the reporting of certain data elements to be added or substantially revised in these proposed amendments. DATES: Comments. Comments must be received on or before July 21, 2023. Comments on the information collection provisions submitted to the Office of Management and Budget (OMB) under the Paperwork Reduction Act (PRA) are best assured of consideration by OMB if OMB receives a copy of your comments on or before June 21, 2023. Public hearing. The EPA does not plan to conduct a public hearing unless requested. If anyone contacts us requesting a public hearing on or before May 30, 2023, we will hold a virtual public hearing. See SUPPLEMENTARY INFORMATION for information on requesting and registering for a public hearing. ADDRESSES: Comments. You may submit comments, identified by Docket Id. No. EPA-HQ-OAR-2019-0424, by any of the following methods: Federal eRulemaking Portal: www.regulations.gov (our preferred method). Follow the online instructions for submitting comments. Mail: U.S. Environmental Protection Agency, EPA Docket Center, Air and Radiation Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460. Hand Delivery or Courier (by scheduled appointment only): EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. The Docket Center's hours of operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal holidays) Instructions: All submissions received must include the Docket Id. No. for this proposed rulemaking. Comments received may be posted without change to www.regulations.gov/, including any personal information provided. For detailed instructions on sending comments and additional information on the rulemaking process, see the “Public Participation” heading of the SUPPLEMENTARY INFORMATION section of this document. The virtual hearing, if requested, will be held using an online meeting platform, and the EPA will provide information on its website ( www.epa.gov/ghgreporting ) regarding how to register and access the hearing. Refer to the SUPPLEMENTARY INFORMATION section for additional information. FOR FURTHER INFORMATION CONTACT: Jennifer Bohman, Climate Change Division, Office of Atmospheric Programs (MC-6207A), Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460; telephone number: (202) 343-9548; email address: GHGReporting@epa.gov. For technical information, please go to the Greenhouse Gas Reporting Program (GHGRP) website, www.epa.gov/ghgreporting. To submit a question, select Help Center, followed by “Contact Us.” World wide web (WWW). In addition to being available in the docket, an electronic copy of this proposal will also be available through the WWW. Following the Administrator's signature, a copy of this proposed rule will be posted on the EPA's GHGRP website at www.epa.gov/ghgreporting. SUPPLEMENTARY INFORMATION: Written comments. Submit your comments, identified by Docket Id. No. EPA-HQ-OAR-2019-0424, at www.regulations.gov (our preferred method), or the other methods identified in the ADDRESSES section. Once submitted, comments cannot be edited or removed from the docket. The EPA may publish any comment received to its public docket. Do not submit to the EPA's docket at www.regulations.gov any information you consider to be confidential business information (CBI), proprietary business information (PBI), or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( i.e., on the web, cloud, or other file sharing system). Please visit www.epa.gov/dockets/commenting-epa-dockets for additional submission methods; the full EPA public comment policy; information about CBI, PBI, or multimedia submissions, and general guidance on making effective comments. Participation in virtual public hearing. To request a virtual public hearing, please contact the person listed in the following FOR FURTHER INFORMATION CONTACT section by May 30, 2023. If requested, the virtual hearing will be held on June 6, 2023. The hearing will convene at 9 a.m. Eastern Time (ET) and will conclude at 3 p.m. ET. The EPA may close the hearing 15 minutes after the last pre-registered speaker has testified if there are no additional speakers. The EPA will provide further information about the hearing on its website ( www.epa.gov/ghgreporting ) if a hearing is requested. If a public hearing is requested, the EPA will begin pre-registering speakers for the hearing no later than one business day after a request has been received. To register to speak at the virtual hearing, please use the online registration form available at www.epa.gov/ghgreporting or contact us by email at GHGReporting@epa.gov. The last day to pre-register to speak at the hearing will be June 5, 2023. On June 5, 2023, the EPA will post a general agenda that will list pre-registered speakers in approximate order at: www.epa.gov/ghgreporting. The EPA will make every effort to follow the schedule as closely as possible on the day of the hearing; however, please plan for the hearings to run either ahead of schedule or behind schedule. Each commenter will have 5 minutes to provide oral testimony. The EPA encourages commenters to provide the EPA with a copy of their oral testimony electronically (via email) by emailing it to GHGReporting@epa.gov. The EPA also recommends submitting the text of your oral testimony as written comments to the rulemaking docket. The EPA may ask clarifying questions during the oral presentations but will not respond to the presentations at that time. Written statements and supporting information submitted during the comment period will be considered with the same weight as oral testimony and supporting information presented at the public hearing. Please note that any updates made to any aspect of the hearing will be posted online at www.epa.gov/ghgreporting. While the EPA expects the hearing to go forward as set forth above, please monitor our website or contact us by email at GHGReporting@epa.gov to determine if there are any updates. The EPA does not intend to publish a document in the Federal Register announcing updates. If you require the services of an interpreter or special accommodation such as audio description, please pre-register for the hearing with the public hearing team and describe your needs by May 30, 2023. The EPA may not be able to arrange accommodations without advanced notice. Regulated entities. This is a proposed regulation. If finalized, these proposed revisions would affect certain entities that must submit annual greenhouse gas (GHG) reports under the GHGRP (40 CFR part 98). These are proposed amendments to existing regulations. If finalized, these amended regulations would also affect owners or operators of certain industry sectors that are direct emitters of GHGs. Regulated categories and entities include, but are not limited to, those listed in Table 1 of this preamble: Table 1—Examples of Affected Entities by Category Category North American Industry Classification System (NAICS) Examples of facilities that may be subject to part 98: Adipic Acid Production 325199 All other basic organic chemical manufacturing: Adipic acid manufacturing. Aluminum Production 331313 Primary aluminum production facilities. Ammonia Manufacturing 325311 Anhydrous ammonia manufacturing facilities. Calcium Carbide Production 325180 Other basic inorganic chemical manufacturing: calcium carbide manufacturing. Carbon Dioxide Enhanced Oil Recovery Projects 211120 Oil and gas extraction projects using carbon dioxide enhanced oil recovery. Caprolactam, Glyoxal, and Glyoxylic Acid Production 325199 All other basic organic chemical manufacturing. Cement Production 327310 Cement manufacturing. Ceramics Manufacturing 327110 Pottery, ceramics, and plumbing fixture manufacturing. 327120 Clay building material and refractories manufacturing. Coke Calcining 299901 Coke; coke, petroleum; coke, calcined petroleum. Electronics Manufacturing 334111 Microcomputers manufacturing facilities. 334413 Semiconductor, photovoltaic (PV) (solid-state) device manufacturing facilities. 334419 Liquid crystal display (LCD) unit screens manufacturing facilities; Microelectromechanical (MEMS) manufacturing facilities. Electrical Equipment Manufacture or Refurbishment 33531 Power transmission and distribution switchgear and specialty transformers manufacturing facilities. Electricity generation units that report through 40 CFR part 75 221112 Electric power generation, fossil fuel ( e.g., coal, oil, gas). Electrical Equipment Use 221121 Electric bulk power transmission and control facilities. Electrical transmission and distribution equipment manufacture or refurbishment 33361 Engine, Turbine, and Power Transmission Equipment Manufacturing. Ferroalloy Production 331110 Ferroalloys manufacturing. Fluorinated Greenhouse Gas Production 325120 Industrial gases manufacturing facilities. Geologic Sequestration NA CO 2 geologic sequestration sites. Glass Production 327211 Flat glass manufacturing facilities. 327213 Glass container manufacturing facilities. 327212 Other pressed and blown glass and glassware manufacturing facilities. HCFC-22 Production 325120 Industrial gas manufacturing: Hydrochlorofluorocarbon (HCFC) gases manufacturing. HFC-23 destruction processes that are not collocated with a HCFC-22 production facility and that destroy more than 2.14 metric tons of HFC-23 per year 325120 Industrial gas manufacturing: Hydrofluorocarbon (HFC) gases manufacturing. Hydrogen Production 325120 Hydrogen manufacturing facilities. Industrial Waste Landfill 562212 Solid waste landfill. Industrial Wastewater Treatment 221310 Water treatment plants. Injection of Carbon Dioxide 211 Oil and gas extraction. Iron and Steel Production 333110 Integrated iron and steel mills, steel companies, sinter plants, blast furnaces, basic oxygen process furnace (BOPF) shops. Lead Production 331 Primary metal manufacturing. Lime Manufacturing 327410 Lime production. Magnesium Production 331410 Nonferrous metal (except aluminum) smelting and refining: Magnesium refining, primary. Nitric Acid Production 325311 Nitrogenous fertilizer manufacturing: Nitric acid manufacturing. Petroleum and Natural Gas Systems 486210 Pipeline transportation of natural gas. 221210 Natural gas distribution facilities. 211120 Crude petroleum extraction. 211130 Natural gas extraction. Petrochemical Production 324110 Petrochemicals made in petroleum refineries. Petroleum Refineries 324110 Petroleum refineries. Phosphoric Acid Production 325312 Phosphatic fertilizer manufacturing. Pulp and Paper Manufacturing 322110 Pulp mills. 322120 Paper mills. 322130 Paperboard mills. Miscellaneous Uses of Carbonate Facilities included elsewhere Municipal Solid Waste Landfills 562212 Solid waste landfills. 221320 Sewage treatment facilities. Silicon Carbide Production 327910 Silicon carbide abrasives manufacturing. Soda Ash Production 325180 Other basic inorganic chemical manufacturing: Soda ash manufacturing. Suppliers of Carbon Dioxide 325120 Industrial gas manufacturing facilities. Suppliers of Industrial Greenhouse Gases 325120 Industrial greenhouse gas manufacturing facilities. Titanium Dioxide Production 325180 Other basic inorganic chemical manufacturing: Titanium dioxide manufacturing. Underground Coal Mines 212115 Underground coal mining. Zinc Production 331410 Nonferrous metal (except aluminum) smelting and refining: Zinc refining, primary. Importers and Exporters of Pre-charged Equipment and Closed-Cell Foams 423730 Air-conditioning equipment (except room units) merchant wholesalers. 333415 Air-conditioning equipment (except motor vehicle) manufacturing. 423620 Air-conditioners, room, merchant wholesalers. 449210 Electronics and Appliance retailers. 326150 Polyurethane foam products manufacturing. 335313 Circuit breakers, power, manufacturing. 423610 Circuit breakers and related equipment merchant wholesalers. Table 1 of this preamble is not intended to be exhaustive, but rather provides a guide for readers regarding facilities likely to be affected by this proposed action. This table lists the types of facilities that the EPA is now aware could potentially be affected by this action. Other types of facilities than those listed in the table could also be subject to reporting requirements. To determine whether you would be affected by this proposed action, you should carefully examine the applicability criteria found in 40 CFR part 98, subpart A (General Provisions) and each source category. Many facilities that are affected by 40 CFR part 98 have greenhouse gas emissions from multiple source categories listed in Table 1 of this preamble. If you have questions regarding the applicability of this action to a particular facility, consult the person listed in the FOR FURTHER INFORMATION CONTACT section. Acronyms and Abbreviations. The following acronyms and abbreviations are used in this document. AGA American Gas Association AIM American Innovation and Manufacturing Act of 2020 ANSI American National Standards Institute API American Petroleum Institute AR5 Fifth Assessment Report AR6 Sixth Assessment Report ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials BACT best available control technology BAMM best available monitoring methods BCFC bromochlorofluorocarbons BFC bromofluorocarbons BOPF basic oxygen process furnace CAA Clean Air Act CAS Chemical Abstract Service CBI confidential business information CBP U.S. Customs and Border Protection CCUS carbon capture, utilization, and sequestration CDC Centers for Disease Control and Prevention CEMS continuous emission monitoring system CFC chlorofluorocarbons CFR Code of Federal Regulations CGA cylinder gas audit CF 4 perfluoromethane CH 4 methane CHP combined heat and power CMA Conference of the Parties serving as the meeting of the Parties to the Paris Agreement CO 2 carbon dioxide CO 2 e carbon dioxide equivalent COVID-19 Coronavirus 2019 CSA CSA Group DOC degradable organic carbon DOE Department of Energy DRE destruction and removal efficiency EGU electricity generating unit e-GGRT electronic Greenhouse Gas Reporting Tool eGRID Emissions & Generation Resource Database EF emission factor EG emission guidelines EIA Energy Information Administration EOR enhanced oil recovery EPA U.S. Environmental Protection Agency ET Eastern time FAQ frequently asked question FR Federal Register F-GHG fluorinated greenhouse gas F-HTFs fluorinated heat transfer fluids GHG greenhouse gas GHGRP Greenhouse Gas Reporting Program GWP global warming potential HAWK HFC and ODS Allowance Tracking HBCFC hydrobromochlorofluorocarbons HBFC hydrobromofluorocarbons HCFC hydrochlorofluorocarbons HCFE hydrochlorofluoroethers HFC hydrofluorocarbons HFE hydrofluoroethers HTF heat transfer fluid HTS Harmonized Tariff System ICR Information Collection Request IPCC Intergovernmental Panel on Climate Change ISBN International Standard Book Number ISO International Standards Organization IVT Inputs Verification Tool k first order decay rate kWh kilowatt hour LDC local distribution company MECS Manufacturing and Energy Consumption Survey MEMP Metered Energy Monitoring Plan mmBtu million British thermal units MRV monitoring, reporting, and verification plan mt metric tons mtCO 2 e metric tons carbon dioxide equivalent MWh megawatt-hour MSW municipal solid waste N 2 O nitrous oxide NAICS North American Industry Classification System NIST National Institute of Standards and Technology NSPS new source performance standards OMB Office of Management and Budget PBI proprietary business information PFC perfluorocarbon POX partial oxidation ppm parts per million PRA Paperwork Reduction Act PSA pressure swing adsorption PSD prevention of significant deterioration QA/QC quality assurance/quality control RFA Regulatory Flexibility Act REC renewable energy credit RY reporting year SAR Second Assessment Report SDI Strategic Defense Initiative SF6 sulfur hexafluoride SMR steam methane reforming TRL technology readiness level TSD technical support document UIC underground injection control U.S. United States UMRA Unfunded Mandates Reform Act of 1995 UNFCCC United Nations Framework Convention on Climate Change WGS water gas shift WWW World Wide Web Contents I. Background A. How is this preamble organized? B. Background on This Supplemental Proposed Rule C. Legal Authority II. Overview and Rationale for Proposed Amendments to 40 CFR Part 98 A. Revisions to Global Warming Potentials B. Revisions To Expand Source Categories and Address Potential Gaps in Reporting of Emissions Data for Specific Sectors C. Improvements to Existing and Proposed Emissions Estimation Methodologies D. Revisions to Reporting Requirements To Improve Verification and the Accuracy of the Data Collected E. Technical Amendments, Clarifications, and Corrections III. Proposed Amendments to Part 98 A. Subpart A—General Provisions B. Subpart C—General Stationary Fuel Combustion Sources C. Subpart F—Aluminum Production D. Subpart G—Ammonia Manufacturing E. Subpart I—Electronics Manufacturing F. Subpart N—Glass Production G. Subpart P—Hydrogen Production H. Subpart Y—Petroleum Refineries I. Subpart AA—Pulp and Paper Manufacturing J. Subpart HH—Municipal Solid Waste Landfills K. Subpart OO—Suppliers of Industrial Greenhouse Gases L. Subpart PP—Suppliers of Carbon Dioxide M. Subpart QQ—Importers and Exporters of Fluorinated Greenhouse Gases Contained in Pre-Charged Equipment and Closed-Cell Foams N. Subpart RR—Geologic Sequestration of Carbon Dioxide O. Subpart UU—Injection of Carbon Dioxide P. Subpart VV—Geologic Sequestration of Carbon Dioxide With Enhanced Oil Recovery Using ISO 27916 IV. Proposed Amendments To Add New Source Categories to Part 98 A. Subpart B—Energy Consumption B. Subpart WW—Coke Calciners C. Subpart XX—Calcium Carbide Production D. Subpart YY—Caprolactam, Glyoxal, and Glyoxylic Acid Production E. Subpart ZZ—Ceramics Production V. Schedule for the Proposed Amendments VI. Proposed Confidentiality Determinations for Certain Data Reporting Elements A. Overview and Background B. Proposed Confidentiality Determinations C. Proposed Reporting Determinations for Inputs to Emissions Equations D. Request for Comments on Proposed Category Assignments, Confidentiality Determinations, or Reporting Determinations VII. Impacts of the Proposed Amendments VIII. Statutory and Executive Order Reviews A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review B. Paperwork Reduction Act (PRA) C. Regulatory Flexibility Act (RFA) D. Unfunded Mandates Reform Act (UMRA) E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer and Advancement Act J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations K. Determination under CAA Section 307(d) I. Background A. How is this preamble organized? Section I of this preamble contains background information on the June 21, 2022 proposed rule (87 FR 36920, hereafter referred to as “2022 Data Quality Improvements Proposal”) and how the EPA identified additional information to support further revisions to improve the GHGRP that are included in this supplemental proposal. This section also discusses the EPA's legal authority under the Clean Air Act (CAA) to promulgate (including subsequent amendments to) the GHG Reporting Rule, codified at 40 CFR part 98 (hereinafter referred to as “part 98”), and the EPA's legal authority to make confidentiality determinations for new or revised data elements required by these amendments or for existing data elements for which a confidentiality determination has not previously been proposed. Section II of this preamble describes the types of amendments included in this proposed rule and includes the rationale for each type of proposed change. Section III of this preamble is organized by existing part 98 subpart and contains detailed information on the proposed revisions and the rationale for the proposed amendments in each section. Section IV of this preamble describes five newly proposed part 98 subparts and contains detailed information and rationale for the requirements for each proposed source category. Section V of this preamble discusses the proposed schedule for implementing these revisions to part 98. Section VI of this preamble discusses the proposed confidentiality determinations for new or substantially revised ( i.e., requiring additional or different data to be reported) data reporting elements, as well as for certain existing data elements for which the EPA is proposing a new determination. Section VII of this preamble discusses the impacts of the proposed amendments. Section VIII of this preamble describes the statutory and Executive order requirements applicable to this action. B. Background on This Supplemental Proposed Rule In the 2022 Data Quality Improvements Proposal, the EPA proposed amendments to specific provisions of the GHGRP where we identified opportunities for improvement, such as where the rule may be modified to reflect the EPA's current understanding of U.S. GHG emission trends, or to improve data collection and reporting where additional data may be necessary to better understand emissions from specific sectors or inform future policy decisions (87 FR 36920, June 21, 2022). The 2022 Data Quality Improvements Proposal included updates to emission factors and refinements to existing emissions estimation methodologies to reflect an improved understanding of emission sources and end uses of GHGs. Additionally, it proposed to collect additional data to understand new source categories or new emission sources for specific sectors; to improve the EPA's understanding of the sector- specific processes or other factors that influence GHG emission rates; to improve verification of collected data; and to provide additional data to complement or inform other EPA programs. In other cases, we proposed revisions to resolve gaps in the current coverage of the GHGRP that leave out potentially significant sources of GHG emissions or end uses. For example, the proposed revisions included new reporting of direct air capture as a carbon capture option for suppliers of carbon dioxide; addition of a new subpart for quantifying geologic sequestration in association with enhanced oil recovery operations; and an updated calculation methodology to estimate emissions from large, atypical release events at oil and gas facilities. The EPA also proposed revisions that clarify or update provisions that may be unclear, or where we identified specific provisions in part 98 that would streamline calculation, monitoring, or reporting to provide flexibility or increase the efficiency of data collection. Finally, the EPA also solicited comment on expanding the GHGRP to include several new source categories that could improve the EPA's understanding of GHGs, including energy consumption; ceramics production; calcium carbide production; caprolactam, glyoxal, and glyoxylic acid production; coke calcining; and CO 2 utilization (see section IV of the 2022 Data Quality Improvements Proposal at 87 FR 37016), as well as requesting comment on potential future amendments to add new calculation, monitoring, and reporting requirements. As stated in the 2022 Data Quality Improvements Proposal, the data collected under part 98 are used to inform the EPA's understanding of the relative emissions and distribution of emissions from specific industries, the factors that influence GHG emission rates, and to inform policy options and potential regulations. Since publishing the proposed amendments, the EPA has received or identified new information to further improve the data collected under the GHGRP, and has subsequently identified additional amendments that the EPA is putting forward in this supplemental proposal. Some of the additional amendments are informed by a review of comments raised by stakeholders on the 2022 Data Quality Improvements Proposal ( e.g., see sections III.J and III.P of this preamble). Other proposed changes are based on additional data gaps the EPA has observed in collected data, either where additional data would improve verification of data reported to the GHGRP (see section II.D of this preamble) or where additional data is needed to help our understanding of changing industry emission trends (see sections II.B and II.C of this preamble). Based on review of this information, the EPA is proposing additional amendments to part 98, described in sections II through IV of this preamble, that build on and improve the amendments proposed in the 2022 Data Quality Improvements Proposal or that would further enhance the quality of part 98 and implementation of the GHGRP. In some cases, the EPA has identified updated guidance on GHG estimation methods or advances in the scientific literature. For example, through this notification, the EPA is proposing a comprehensive update to the global warming potentials (GWPs) in Table A-1 to subpart A of part 98, in part to ensure that the GWPs used in the GHGRP are consistent with those recently agreed upon by the Parties to the United Nations Framework Convention on Climate Change (UNFCCC) for purposes of GHG reporting. The Parties specified the agreed-on GWPs in November 2021 (see section III.A.1 of this preamble), which was too late to allow the EPA to consider proposing a comprehensive GWP update in the 2022 Data Quality Improvement Proposal. 1 We have subsequently reviewed and are proposing to include updated GWPs in this proposed rule. 1 Although we proposed changes to certain chemical specific and default global warming potentials in Table A-1 to subpart A of part 98 in the 2022 Data Quality Improvements Proposal, these were limited updates to GWPs of fluorinated GHGs that are not required to be reported under the UNFCCC because they are not hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, or nitrogen trifluoride. In other cases, we have identified new data supporting additional improvements to the calculation, monitoring, and recordkeeping requirements, including revisions and clarifications not previously proposed, that would address potential data gaps and improve the quality of the data collected in the GHGRP. For example, the EPA is proposing to incorporate additional revisions to the Municipal Solid Waste (MSW) landfill source category in light of recent aerial studies that indicate that methane emissions from landfills may be considerably higher than the methane emissions currently reported under subpart HH of part 98 (Municipal Solid Waste Landfills). The proposed amendments incorporate an updated emissions estimation methodology that would improve the accuracy and coverage of the greenhouse gas data from landfills. These data would be used to inform the EPA's understanding of methane emissions from MSW landfills and future policy decisions under the CAA. For example, the current equations account for fugitive methane emissions passing through intact cover systems. Collecting surface emissions data under the proposed revisions would inform the EPA's understanding of the degree to which breakdown in cover materials is occurring and the impacts on methane emission rates. This supplemental proposal also incorporates consideration of information received in response to our request for comment on certain topics in the 2022 Data Quality Improvement Proposal. In that proposal, we requested comment on potential future amendments to improve the coverage of U.S. GHG emissions and supply captured by the GHGRP. The EPA has reviewed comments received in response to the call for information, along with additional data that the EPA has collected, and is proposing to establish new subparts with specific reporting provisions under part 98 for the source categories of energy consumption; coke calciners; ceramics production; calcium carbide production; and caprolactam, glyoxal, and glyoxylic acid production. The proposed revisions would improve the data collected under the GHGRP by better capturing the changing landscape of greenhouse gas emissions, providing for more complete coverage of U.S. GHG emission sources, and providing a more comprehensive approach to understanding GHG emissions. For other revisions, we are proposing to clarify or correct specific proposed provisions of the 2022 Data Quality Improvements Proposal. For instance, we are proposing to clarify the applicability requirements of proposed subpart VV of part 98 (Geologic Sequestration of Carbon Dioxide With Enhanced Oil Recovery Using ISO 27916), a new subpart for quantifying geologic sequestration in association with enhanced oil recovery (EOR) operations, which was included in the 2022 Data Quality Improvements Proposal. Following the initial proposal, we received feedback from stakeholders highlighting ambiguity in the applicability of the proposed source category and questioning whether EOR operators electing to use the International Standards Organization (ISO) standard designated as CSA Group (CSA)/American National Standards Institute (ANSI) ISO 27916:2019, Carbon Dioxide Capture, Transportation and Geological Storage—Carbon Dioxide Storage Using Enhanced Oil Recovery (CO 2 -EOR) (hereafter referred to as “CSA/ANSI ISO 27916:2019”), must mandatorily report under the new proposed subpart VV or would have the option to continue reporting under subpart UU (Injection of Carbon Dioxide). We are proposing the applicability of the source category in this supplemental notification to better reflect our initial intent, which was that operators electing to use CSA/ANSI ISO 27916:2019 to quantify geologic sequestration of CO 2 would be required to report under subpart VV, and proposing harmonizing revisions to subpart UU (Injection of Carbon Dioxide). This supplemental proposal provides information about these proposed updates for public review and comment. This supplemental proposal does not address implementation of provisions of the Inflation Reduction Act which was signed into law on August 16, 2022. Section 60113 of the Inflation Reduction Act amended the CAA by adding section 136, “Methane Emissions and Waste Reduction Incentive Program for Petroleum and Natural Gas Systems.” The EPA intends to take one or more separate actions in the coming months related to implementation of the Methane Emissions and Waste Reduction Incentive Program, including a future rulemaking to propose revisions to certain requirements of subpart W of part 98 (Petroleum and Natural Gas Systems). Accordingly, the Methane Emissions and Waste Reduction Incentive Program is outside the scope of this supplemental proposed rule. C. Legal Authority The EPA is proposing these rule amendments under its existing CAA authority provided in CAA section 114. As stated in the preamble to the Mandatory Reporting of Greenhouse Gase s final rule (74 FR 56260, October 30, 2009) (hereinafter referred to as “2009 Final Rule”), CAA section 114(a)(1) provides the EPA broad authority to require the information proposed to be gathered by this rule because such data would inform and are relevant to the EPA's carrying out of a variety of CAA provisions. See the preambles to the proposed GHG Reporting Rule (74 FR 16448, April 10, 2009) (hereinafter referred to as “2009 Proposed Rule”) and the 2009 Final Rule for further information. II. Overview and Rationale for Proposed Amendments to 40 CFR Part 98 In general, this supplemental proposal includes the following proposed revisions to better inform EPA policies and programs under the CAA: • Revisions to Table A-1 to the General Provisions of part 98 to include updated GWPs to reflect advances in scientific knowledge and better characterize the climate impacts of certain GHGs, including agreed-upon values established by the UNFCCC, and to maintain comparability and consistency with the Inventory of U.S. Greenhouse Gas Emissions and Sinks 2 (hereafter referred to as “the Inventory”) and other analyses produced by the EPA; 2 The EPA's GHG Inventory is available at https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks. • Revisions to expand source categories or add new source categories to address potential gaps in reporting of emissions data for specific sectors in order to improve the accuracy and completeness of the data provided by the GHGRP; • Revisions to refine existing calculation methodologies to reflect an improved understanding of emissions sources and end uses of GHGs, to incorporate more recent research on GHG emissions or formation, or to improve verification of reported emissions; • Revisions to add or modify reporting requirements to eliminate data gaps and improve verification of emissions estimates; and • Revisions that clarify requirements that reporters have previously found vague to ensure that accurate data are being collected, and editorial corrections or harmonizing changes that would improve the public's understanding of the rule. Overall, the proposed changes in this supplemental notification would provide a more comprehensive, nationwide GHG emissions profile reflective of the origin and distribution of GHG emissions in the United States and would more accurately inform EPA policy options for potential regulatory or non-regulatory CAA programs. The EPA additionally uses the data from the GHGRP, which would include data from these proposed changes, to improve estimates used in the Inventory. Sections II.A through II.E of this preamble provide additional rationale for the proposed changes. Details for the specific amendments proposed for each subpart are included in sections III and IV of this preamble. We are seeking public comment only on the proposed revisions and issues specifically identified in this supplemental notification for the identified subparts. We expect to deem any comments received in response to this notification that address other aspects of 40 CFR part 98 to be outside of the scope of this supplemental proposed rulemaking. A. Revisions to Global Warming Potentials Table A-1 to subpart A of 40 CFR part 98 (“Table A-1”) is a compendium of chemical-specific and default GWP values of GHGs that are required to be reported under one or more subparts of the GHG Reporting Rule. These GWPs are used to convert tons of chemical into tons of CO 2 -equivalent (CO 2 e) for purposes of various calculations and reporting under the rule. The EPA is proposing revisions to Table A-1 to update the chemical-specific GWP values of certain GHGs to reflect GWPs from the IPCC Fifth Assessment Report (hereinafter referred to as “AR5”) 3 and, for certain GHGs that do not have chemical-specific GWPs listed in AR5, to adopt GWP values from the IPCC Sixth Assessment Report (hereinafter referred to as “AR6”). 4 The EPA is also proposing to revise and expand the set of default GWPs in Table A-1, which are applied to GHGs for which peer-reviewed chemical-specific GWPs are not available. With these changes, the GWP values in Table A-1 would reflect more recent science regarding the atmospheric impacts of non-CO 2 GHGs, and the GWP values used for the GHGRP would continue to be consistent with the GWP values used for the Inventory and other EPA programs. (As discussed further below, the Inventory incorporates the GWP values agreed on by the parties to the UNFCCC, who agreed to use the GWP values in AR5 beginning in 2024.) 3 IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. The GWPs are listed in Table 8.A.1 of Appendix 8.A: Lifetimes, Radiative Efficiencies and Metric Values, which appears on pp. 731-737 of Chapter 8, “Anthropogenic and Natural Radiative Forcing.” 4 Smith, C., Z.R.J. Nicholls, K. Armour, W. Collins, P. Forster, M. Meinshausen, M.D. Palmer, and M. Watanabe, 2021: The Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity Supplementary Material. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Available from www.ipcc.ch/ The AR6 GWPs are listed in Table 7.SM.7, which appears on page 16 of the Supplementary Material. As discussed in this section of the preamble, the GWP values currently in Table A-1 to part 98 are drawn both from the IPCC Fourth Assessment Report 5 (hereinafter referred to as “AR4”) and, for multiple GHGs that do not have GWPs listed in AR4, from AR5. The proposed GWP values are drawn from AR5, and for multiple GHGs that do not have GWPs listed in AR5, from AR6. Consistent with our approach since the inception of the GHGRP, we are proposing to adopt the AR5 and AR6 GWPs based on a 100-year time horizon. Note that these proposed revisions are in addition to the 2022 Data Quality Improvements Proposal to add a chemical-specific GWP of 0.14 for carbonic difluoride and to expand the fluorinated greenhouse gas (F-GHG) group for several types of unsaturated compounds to include additional types of unsaturated compounds. GWPs that have been newly evaluated or reevaluated in the peer-reviewed scientific literature are periodically consolidated and published by the IPCC. Since 1990, there have been six IPCC Assessment Reports, each of which included a set of revised and expanded GWPs. For purposes of reporting their GHG emissions under the UNFCCC, the Parties to the UNFCCC have successively adopted the 100-year GWPs in three of the IPCC Assessment Reports, beginning with the SAR, advancing to AR4 and, starting in 2024, moving to AR5. 5 IPCC Fourth Assessment Report (AR4), 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp. Published in 2014, AR5 includes revised GWPs for the GHGs with GWPs in AR4 as well as for multiple additional GHGs. The revised GWPs reflect advances in scientific knowledge on the radiative efficiencies, atmospheric lifetimes, and other characteristics of these GHGs and of CO 2 , and they also account for the growing background concentrations of GHGs (particularly CO 2 ) in the atmosphere. 6 AR5 therefore reflects an improved scientific understanding of the radiative effects 7 of these gases in the atmosphere. As noted in the preamble to the 2009 Final Rule, it is the EPA's intent to periodically update Table A-1 through notice and comment rulemaking as GWPs are evaluated or re-evaluated by the scientific community (74 FR 56348; October 30, 2009). Further, as noted in the preamble to the 2013 Revisions to the Greenhouse Gas Reporting Rule and Final Confidentiality Determinations for New or Substantially Revised Data Elements (78 FR 71904, 71911; November 29, 2013, hereafter “the 2013 Final Rule”), which updated GWPs in Table A-1, “each successive assessment provides more accurate GWP estimates as experiments and improved computational methods lead to more accurate estimates of the radiative efficiencies, atmospheric lifetimes, and indirect effects of the various gases. Additionally, the more recent assessments reflect more up-to-date background concentrations, which are necessary for accurately calculating the radiative efficiency of the different gases.” Therefore, adopting the GWP values in AR5 (and in AR6 for GHGs that do not have GWPs in AR5) would support the overall goals of the GHGRP to collect high-quality GHG data and to incorporate metrics that reflect scientific updates as they are adopted. 6 Increasing background concentrations of a GHG in the atmosphere can lower the impact of subsequent emissions. 7 Radiative forcing is the measurement of the capacity of a gas or other forcing agent to affect the balance of energy in Earth's atmosphere based in the difference in incoming solar radiation and outgoing infrared radiation. The proposed changes to Table A-1 would also ensure that the data collected in the GHGRP can be compared to the data collected and presented by other EPA programs and by national and international GHG inventories. The proposed changes, with a proposed effective date of January 1, 2025 (therefore applicable to data submitted for calendar year/reporting year 2024, i.e., RY2024), 8 would maintain long-term consistency between the GHGRP GWPs and the GWPs used for the Inventory, which are scheduled to change from the AR4 GWPs to the AR5 GWPs for the 1990-2022 Inventory. 9 8 As discussed in section III.A.2 of the preamble, current 40 CFR 98.3(k) provides that facilities or suppliers that first become subject to any subpart of part 98 solely due to an amendment to Table A-1 are not required to submit an annual GHG report (or, for facilities or suppliers that already report under the GHGRP, a report for the subpart to which they are newly subject) for the reporting year during which the change in GWPs is published. However, they are required to begin monitoring their emissions and supplies for the subpart(s) to which they are newly subject beginning on January 1 of the year following publication of the amendment to Table A-1. 9 Due to the time required to complete this proposed rule to adopt the AR5 GWPs, if this proposed rule is finalized, emissions from at least two years, 2022 and 2023, would be weighted by different sets of GWPs under part 98 and the Inventory. The Inventory is a comprehensive assessment of U.S. GHG emissions based on national-level data and follows the reporting guidelines set by the UNFCCC. 10 The United States is a party to the UNFCCC and submits the Inventory to the Secretariat of the UNFCCC as part of annual obligations under the treaty. To ensure consistency and comparability with national inventory data submitted by other UNFCCC Parties, the Inventory submitted to the UNFCCC uses internationally accepted methods and common reporting metrics agreed upon by the Parties (including the United States) to develop and characterize emission estimates. 10 See Articles 4 and 12 of the Convention on Climate Change. Parties to the Convention, by ratifying, “shall develop, periodically update, publish and make available * * * national inventories of anthropogenic emissions by sources and removals by sinks of all greenhouse gases not controlled by the Montreal Protocol, using comparable methodologies * * *.” See https://unfccc.int/resource/docs/convkp/conveng.pdf. As described in the preamble of the 2009 Proposed Rule, the GHGRP is intended to gather information that is relevant to the EPA's carrying out a wide variety of CAA provisions, with the goal of supplementing and complementing existing U.S. Government programs related to climate policy and research, including the Inventory submitted to the UNFCCC. The GHGRP provides data that can inform analysis of potential U.S. climate policies and programs, which is also one of the uses for the data developed for the Inventory. The GHGRP complements the Inventory and other U.S. programs by providing data from certain individual facilities and suppliers, generally those above certain thresholds. Collected facility, unit, and process-level GHG data from the GHGRP are also used to develop and confirm the national statistics and emission estimates presented in the Inventory, which are calculated using aggregated national data. Throughout the development and implementation of the GHG Reporting Rule, the EPA has proposed and finalized calculation methodologies and reporting metrics that were consistent with the international reporting standards under the UNFCCC. This approach has allowed the data collected under the GHGRP to be easily compared to the data in the Inventory and to data from other national and international programs, facilitating the analysis of potential U.S. climate policies and programs. Specifically, in the 2009 Final Rule, the EPA generally promulgated GWP values published in the IPCC Second Assessment Report 11 (hereafter referred to as “SAR GWP values”) to convert mass emissions (or supplies) of each GHG into a common unit of measure, CO 2 e, for final reporting. Although the IPCC published AR4 prior to publication of the 2009 Final Rule, the UNFCCC continued to require the use of SAR GWP values for reporting in the Inventory at the time the rule was promulgated, and up until 2014. 12 In the 2013 Final Rule, the EPA revised the GHGRP's GWP values, after consideration of a UNFCCC decision reached by UNFCCC member parties and published on March 15, 2012, to require countries submitting an annual inventory report in 2015 and beyond to use AR4 GWP values. 13 The 2013 Final Rule adopted the IPCC AR4 GWP values in Table A-1, in part in order to maintain comparability and consistency with the updated international reporting standards under the UNFCCC and the revised requirements for official emission estimates to be reported by the United States and other parties. Following the 2013 Final Rule, the EPA published a separate rule to add GWPs to Table A-1 for a number of F-GHGs and fluorinated heat transfer fluids (F-HTFs) for which GWPs were not provided in AR4 or previous scientific assessments (79 FR 73750, December 11, 2014, hereinafter referred to as the “2014 Fluorinated GHG Final Rule”). 14 The 2014 Fluorinated GHG Final Rule included chemical-specific GWPs primarily drawn from AR5, as well as default GWPs intended for F-GHGs and F-HTFs for which peer-reviewed GWPs were not available in AR4, AR5, or other sources. The default GWPs were calculated and applied to 12 fluorinated GHG groups composed of compounds with similar chemical structures, atmospheric lifetimes, and GWPs, and were based on the average GWPs of the chemically similar fluorinated GHGs for which a chemical-specific GWP was available in Table A-1 or AR5. As such, the changes from the 2014 Fluorinated GHG Final Rule reflected the latest scientific consensus regarding F-GHGs that did not have GWPs in earlier assessments and expanded the number of compounds reflected in Table A-1, resulting in more accurate and complete estimates of GHG emissions. At the same time, the 2014 Fluorinated GHG Final Rule maintained consistency between the GHGRP and the Inventory by retaining the AR4 GWP values where those were available. 11 IPCC Second Assessment Report (SAR), 1995. Climate Change 1995: The Science of Climate Change, Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change [Houghton, J.T.; Meira Filho, L.G.; Callander, B.A.; Harris, N.; Kattenberg, A.; Maskell, K. (eds.)., Cambridge University Press, Cambridge, United Kingdom, 572 pp. 12 As discussed further in this section of this preamble, the EPA did adopt AR4 values in 2009 for GHGs that did not have SAR GWP values because doing so increased the accuracy and completeness of the GWP-weighted emissions calculated and reported under the GHGRP without introducing any inconsistency with UNFCCC reporting. 13 Refer to https://unfccc.int/. See Decision 15/CP.17, Revision of the UNFCCC reporting guidelines on annual inventories for Parties included in Annex I to the Convention. 14 As noted in the 2014 Fluorinated GHG Final Rule, the addition of GWPs for compounds that did not have GWPs in AR4 was consistent with the UNFCCC Reporting Guidelines, which “strongly encourage” Annex I Parties “to also report emissions and removals of additional GHGs” ( i.e., GHGs whose GWPs are not included in AR4). In the 2013 Final Rule, we noted “the EPA may consider adoption of AR5 GWPs or other GWP values for compounds currently listed in Table A-1 ( i.e., compounds for which AR4 GWPs are currently listed in Table A-1) if these values are adopted by the UNFCCC and the global community” (78 FR 71912; November 29, 2013). In December 2018, the Parties to the UNFCCC agreed to require use of the 100-year time-horizon GWP values from AR5 in annual inventory reports submitted in 2024 and future years. 15 In November 2021, the parties clarified which of the two sets of GWPs in AR5 were to be used: those in Table 8.A.1. 16 Accordingly, the United States has an annual commitment to submit the Inventory for 2024 and subsequent years using the revised AR5 GWP values in Table 8.A.1. The Inventory for 2024 will contain national-level estimates of emissions for each year from 1990-2022. In order to ensure that the GHGRP continues to rely on recent scientific data and uses methods consistent with UNFCCC guidelines, as the EPA intended in the development of the 2009 Final Rule and in revisions to the GHGRP since then, we are proposing to revise the GWP values in Table A-1 of part 98 to reflect updated AR5 GWP values, which would apply to annual reports beginning with RY2024. The proposed changes would continue to keep the reporting metrics in part 98 consistent with the updated international reporting standards followed by the Inventory and allow the GHGRP to continue to provide the additional benefit of complementing and informing the Inventory submitted to the UNFCCC. 17 15 Refer to https://unfccc.int/. See Annex to Decision 18/CMA.1, paragraph 37. “Each Party shall use the 100-year time-horizon global warming potential (GWP) values from the IPCC Fifth Assessment Report, or 100-year time-horizon GWP values from a subsequent IPCC assessment report as agreed upon by the [Conference of the Parties serving as the meeting of the Parties to the Paris Agreement] (CMA), to report aggregate emissions and removals of GHGs, expressed in CO2 eq.” 16 Decision 5/CMA.3, paragraph 25 reads “the 100-year time-horizon global warming potential values referred to in decision 18/CMA.1, annex, paragraph 37, shall be those listed in Table 8.A.1 of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, excluding the value for fossil methane.” See https://unfccc.int/sites/default/files/resource/CMA2021_L10a2E.pdf. 17 The updates to Table A-1 would not affect the GWP-weighted, CO 2 -equivalent totals certified by facilities or suppliers in their annual reports for reporting years before RY2023. However, to ensure that GWP-weighted totals are used in analyses and displayed to the public in a consistent manner from RY2010/2011 through RY2023 and later years, the updated GWPs would be applied to the entire time series in analyses and in EPA's Facility Level Information on GreenHouse gases Tool (FLIGHT) at https://ghgdata.epa.gov/ghgp/main.do. This approach is consistent with the approach taken for previous updates of Table A-1. See, e.g., 78 FR 71937. For GHGs that do not have GWPs in AR5 but do have GWPs in AR6, we are proposing to adopt the AR6 GWPs. Currently, default GWPs are applied to these compounds based on the fluorinated GHG group to which they belong. While the default GWPs are, on average, expected to be reasonably accurate across the fluorinated GHGs within a fluorinated GHG group, the AR6 GWP for an individual compound is expected to be more accurate for that compound than the corresponding default GWP. This is because the AR6 GWP takes into consideration the radiative efficiency and atmospheric lifetime of the individual compound. Thus, adopting the AR6 GWPs for GHGs that do not have GWPs in AR5 is expected to improve the accuracy with which the atmospheric impacts of the gases are reflected in annual reports, threshold determinations, and other calculations. The specific changes that we are proposing to Table A-1 and the rationale for the GWPs proposed to be adopted are described further in section III.A.1 of this preamble. We recognize that some other EPA programs use the GWP values in Table A-1 to determine the applicability of their individual program requirements to direct emitters or suppliers above certain thresholds. Issues related to other EPA programs that use the GHGRP GWP values in Table A-1 are outside the scope of this proposed rule. To the extent that a Table A-1 amendment raises such questions or concerns, please work with the respective EPA office for that other EPA program. We also recognize that non-EPA programs use the GWP values in Table A-1 to part 98. Issues related to non-EPA programs that use the GHGRP GWP values in Table A-1 are also outside the scope of this proposed rule. As explained in this section above, this rulemaking proposes to update GWPs for the GHGRP consistent with recent science and the intent the EPA expressed at the time the GHGRP was first promulgated. Thus, under this supplemental proposal, we are seeking comments on the specific GWP values proposed in this action for the GHGRP. B. Revisions To Expand Source Categories and Address Potential Gaps in Reporting of Emissions Data for Specific Sectors In the 2022 Data Quality Improvements Proposal, the Agency stated that it was considering future revisions to the GHG Reporting Rule to potentially expand existing source categories or develop new source categories that would add calculation, monitoring, reporting, and recordkeeping requirements for certain sectors of the economy. Specifically, the 2022 Data Quality Improvements Proposal solicited comment on the potential addition of GHG reporting requirements related to energy consumption; CO 2 utilization; ceramics production; calcium carbide production; caprolactam, glyoxal, and glyoxylic acid production; and coke calcining. The EPA solicited comment on these six source categories where we identified that additional data from these emission sources would help eliminate data gaps, improve the coverage of the GHGRP, and better inform future EPA policy and programs under the CAA. We identified cases where certain emission sources may potentially contribute significant GHG emissions that are not currently reported, or where facilities representative of these source categories may currently report under another part 98 source category using methodologies that may not provide complete or accurate emissions. We also identified where the inclusion of potential source categories would improve the completeness of the emissions estimates presented in the Inventory, such as collection of data on ceramics production, calcium carbide production, and caprolactam, glyoxal, and glyoxylic acid production. The 2022 Data Quality Improvements Proposal also included similar amendments to add reporting of new emissions or emissions sources for certain existing sectors to address potential gaps in reporting, e.g., where we proposed to add requirements for the monitoring, calculation, and reporting of F-GHGs other than SF 6 and perfluorocarbons (PFCs) under subpart DD (Electrical Equipment and Distribution Equipment Use) to account for the introduction of alternative technologies and replacements for SF 6 , including fluorinated gas mixtures such as fluoronitriles or fluoroketones mixed with carrier gases, as a replacement for dielectric insulation gases (87 FR 37000; June 21, 2022). Following the June 21, 2022 request for comment, the EPA has reviewed information provided from stakeholders and considered additional data to further support the development of reporting requirements for five source categories. After that consideration, we are proposing to add annual reporting requirements for greenhouse gases from the following sources categories in new subparts to part 98 as follows: subpart B (Energy Consumption); subpart WW (Coke Calciners); subpart XX (Calcium Carbide Production); subpart YY (Caprolactam, Glyoxal, and Glyoxylic Acid Production); and subpart ZZ (Ceramics Production). As explained in the 2022 Data Quality Improvements Proposal, the collection of such data would continue to inform, and are relevant to, the EPA's carrying out a wide variety of CAA provisions. Additional information on the data and rationale informing the proposed definition of the source category, reporting thresholds, calculation, monitoring, quality assurance, missing data, verification, and data reporting and recordkeeping requirements for these five proposed new source categories are included in section IV of this preamble. The EPA is also proposing amendments that would expand the coverage of the GHGRP for one subpart not included in the 2022 Data Quality Improvements Proposal. Since the publication of the proposed rule, we have identified a gap in coverage for certain emission sources, where revisions to existing applicability and reporting requirements would help the EPA to better understand and track emissions in specific sectors and better inform future EPA policy and programs under the CAA. In this supplemental proposal, we are proposing to amend the applicability of subpart P (Hydrogen Production) to expand reporting to include all hydrogen plants. The current source category definition in subpart P is limited to merchant hydrogen production facilities, including facilities that sell hydrogen and that may be located within another facility if they are not owned by, or under the direct control of, the other facility's owner and operator. The current definition inadvertently excludes non-merchant hydrogen production facilities ( i.e., facilities that do not sell hydrogen or captive hydrogen plants). Although some non-merchant hydrogen production facilities may report under subpart Y (Petroleum Refineries), the EPA has identified that there may be other non-merchant or captive hydrogen plants whose emissions are not currently captured by part 98. The proposed amendments would address this gap in reporting and allow the EPA to better understand and track emissions from these facilities, which would better inform future EPA policy and programs under the CAA. Section III.G of this preamble provides additional information on the proposed amendments. Additionally, we are proposing to amend subpart HH (Municipal Solid Waste Landfills) to expand reporting to account for methane emissions from large releases that are currently not quantified under the GHGRP. Specifically, we are proposing to revise calculation methodologies in subpart HH to account for cover system leaks to better account for large release events. The EPA has identified recent studies indicating that methane emissions from landfills may be considerably higher than what is currently reported to part 98 due to emissions from poorly operating gas collection systems or destruction devices and cover system leaks. We are proposing to revise the monitoring and calculation methodologies in subpart HH to account for these scenarios. Specifically, we note that owners or operators of landfills with gas collection systems subject to the control requirements in the new source performance standards (NSPS) as implemented in 40 CFR part 60, subparts WWW or XXX, emission guidelines (EG) as implemented in 40 CFR part 60, subparts Cc or Cf, or the Federal plan as implemented in 40 CFR part 62, subparts GGG and OOO are required to conduct surface methane concentration measurements to ensure proper operation of the gas collection system. We are proposing that subpart HH reporters with landfills for which surface methane concentration measurements are conducted under the NSPS, EG, or Federal plan would estimate emissions for cover leaks based on a count of the number of exceedances identified during the surface measurement period and the proposed revised equations HH-6, HH-7, and HH-8 to adjust reported methane emissions to account for these exceedances. Subpart HH reporters with landfills with gas collection systems that are not required to conduct surface methane concentration measurements under the NSPS, EG, or Federal plan may elect to conduct these measurements according to the method provided in the proposal and adjust the emissions based on the number of exceedances identified. If such subpart HH reporters do not elect to conduct such measurements, the EPA is proposing that reporters with these landfills would use a surface methane collection efficiency that is 10 percent lower than for landfills with gas collection systems that are conducting surface methane concentration measurements. These proposed amendments would address a potentially large subset of emissions that are currently omitted in reporting and improve the EPA's understanding of emissions from these facilities. The improved data would subsequently better inform Agency policies and programs under the CAA. C. Improvements to Existing Emissions Estimation Methodologies The EPA is proposing several additional revisions to modify calculation equations to incorporate refinements to methodologies based on an improved understanding of emission sources. In the 2022 Data Quality Improvements Proposal, we identified amendments to emission estimation methodologies where there are discrepancies between assumptions in the current emission estimation methods and the processes or activities conducted at specific facilities, or where we identified more recent studies on GHG emissions or formation that reflect updates to scientific understanding of GHG emissions sources. We proposed changes that are intended to improve the quality and accuracy of the data collected under the GHGRP, increase our understanding of the relative distribution of GHGs that are emitted, and better reflect GHG end uses or where GHGs are bound in products. Since the development of the 2022 Data Quality Improvements Proposal, we have identified several calculation provisions of part 98 that would benefit from amendments that update, clarify, or improve the calculation methodology. For example, we are proposing to revise calculation methodologies in subpart HH (Municipal Solid Waste Landfills) to more clearly delineate the calculations needed when there are multiple landfill gas recovery systems in place. During verification of subpart HH reports, we identified issues in how the electronic Greenhouse Gas Reporting Tool (e-GGRT) system calculates emissions when multiple control devices are associated with a single measurement location and when multiple measurement locations may be used for a single recovery system. If a single recovery system is used, but an additional measurement location is added to the system in mid-year, the “f Rec,c ” term associated with the new measurement location (currently, the fraction of annual operating hours the associated recovery system was operating) is calculated as 0.5 and assumes the recovery system operated only half the year. The current equations (equations HH-7 and HH-8) are set up with the assumption that each measurement location is associated with a single recovery system, however this is not always the case. We also found errors in determining the “f Dest ” term (fraction of annual hours the destruction device was operating) in equations HH-6 and HH-8 when multiple destruction devices are used for a single measurement location. If, for example, a measurement location operates continuously (8,760 hours per year), with flow from the measurement location directed to an engine (approximately 8,400 hours per year), diverted to a flare when the engine is down for maintenance (approximately 360 hours per year), and if the control devices were operating at all times gas was directed to the device, the f Dest term should be 1 for each device. However, the f Dest term is often calculated as the average of 0.959 (8400/8760) and 0.041 (360/8760), resulting in a value of 0.5. Therefore, we are proposing revisions to equations HH-6, HH-7, and HH-8 to more clearly define these terms, as well as to adjust the equations to be able to account for landfills with multiple gas collection systems or for a single gas collection system with multiple measurement locations. These proposed revisions would improve the quality and accuracy of the data collected under subpart HH. We are proposing to clarify the calculation methodology for reporters whose hydrogen unit routes process emissions to a stack with CEMS, but fuel combustion emissions from the unit are routed to a different stack which is not monitored with a CEMS. The proposed rule would require reporters to calculate the CO 2 emissions from fuel combustion from the hydrogen process unit using the mass balance equations in subpart P (Hydrogen Production) considering only fuel inputs and report the sum of these emissions plus the process CO 2 emissions measured by the CEMS. The proposed amendments would clarify the reporting requirements for cases where hydrogen production process and combustion emissions are emitted through separate stacks and the process emissions are measured with a CEMS, but the combustion emissions are not. We are also proposing to revise subpart AA (Pulp and Paper Manufacturing) to add a calculation methodology for biogenic CO 2 emissions from the combustion of biomass other than spent liquor solids. The rule currently only includes methodologies to calculate CO 2 , CH 4 , and N 2 O emissions from the combustion of fossil fuels, and CH 4 , N 2 O, and biogenic CO 2 emissions from the combustion of spent liquor solids. Therefore, we are proposing to add methodologies to calculate CH 4 , N 2 O, and biogenic CO 2 emissions from the combustion of biomass fuels other than spent liquor solids, as well as the combustion of biomass other than spent liquor solids with other fuels. The proposed amendments would provide a more accurate accounting of CO 2 and biogenic CO 2 for subpart AA units in this situation. See section III.I of this preamble for additional information. D. Revisions To Reporting Requirements To Improve Verification and the Accuracy of the Data Collected In the 2022 Data Quality Improvements Proposal, the EPA proposed several revisions to existing reporting requirements to improve the quality of the data that are currently reported, to collect more useful data to improve verification of reported data, to better characterize U.S. GHG emissions and trends, and to extend the usefulness of the GHGRP to inform and improve the EPA's ability to carry out other CAA programs. See section II.A.4 of the 2022 Data Quality Improvements Proposal for additional information. In this supplemental proposal, the EPA is proposing new revisions to reporting requirements where we have identified additional data that would further support these goals and improve the quality of the GHGRP. In some cases, the EPA is proposing to collect additional information that would better inform the development of GHG policies and programs by providing information on GHG uses and their relative importance in specific sectors. For example, we are proposing to add reporting requirements to subpart OO (Suppliers of Industrial Greenhouse Gases) to require industrial gas suppliers to identify the end-use applications for which F-HTFs are used and the approximate quantities used in each application. The EPA recently proposed a similar requirement for N 2 O, PFCs, and SF 6 in the 2022 Data Quality Improvements Proposal; this supplemental notification extends the proposed revisions to include F-HTFs to better account for emissions from the use and distribution of F-HTFs which are not otherwise accounted for in the current source categories under part 98. See section III.K of this preamble for additional information. The proposed revisions would also provide more useful data that would improve verification of reported data. For example, we are proposing to revise the existing reporting and recordkeeping requirements in subpart N (Glass Production) for both facilities using continuous electronic monitoring systems (CEMS) and non-CEMS facilities ( i.e., facilities that use a mass balance calculation method) to require reporting and recordkeeping of the annual amounts of recycled scrap glass (cullet) used as a raw material. The EPA is proposing to collect this information because the use of cullet, which contains no carbonates that can be converted to CO 2 emissions, can lead to reductions in emissions from the production of various glass types. The proposed data element would help to inform the EPA's understanding of the variations and differences in emissions estimates within this sector, improve understanding of industry trends, and improve verification of collected data. As discussed in section II of this preamble and in prior amendments, the GHGRP is intended to supplement and complement other EPA programs by advancing the understanding of emission processes and monitoring methodologies for particular source categories or sectors. Similarly, for subpart Y (Petroleum Refineries), we are proposing to include a requirement to report the capacity of each asphalt blowing unit. Although subpart Y currently includes unit-level capacity reporting requirements for other emission units ( e.g., catalytic cracking units, fluid coking units, sulfur recovery plants, coke calcining units, delayed coking units), the EPA lacks data on the capacities of asphalt blowing units. Individual unit information allows the EPA to aggregate emissions according to unit type and size and provides a better understanding of the emissions from specific unit types. Therefore, the proposed revisions to subpart Y would improve emissions analysis and verification for these units. The proposed changes to reporting requirements in this supplemental notification would further enable the EPA to obtain data that is of sufficient quality that it can be used to support a range of future climate change policies and regulations, in keeping with the EPA's CAA section 114 authorities. E. Technical Amendments, Clarifications, and Corrections This supplemental proposal includes several other proposed technical amendments, corrections, and clarifications that have been identified following the 2022 Data Quality Improvements Proposal and that would improve understanding of the rule. The proposed amendments include revisions that better reflect the EPA's intent and include editorial changes, revisions that resolve uncertainties in the regulatory text, and amendments that would increase the likelihood that reporters will submit accurate reports. Some of the proposed changes result from consideration of questions raised by reporters through the GHGRP Help Desk or e-GGRT. For example, we are proposing to add a definition for the term “offshore” to subpart RR (Geologic Sequestration of Carbon Dioxide) to clarify questions raised by stakeholders regarding the applicability of subpart RR to specific offshore geologic sequestration activities. Although the EPA previously noted that the source category covers both onshore and offshore injection of CO 2 in its 2010 final rule (75 FR 75060, December 1, 2010), we are aware that we have not previously provided a definition for the term “offshore.” The proposed definition would clarify the boundaries of injection activities that are currently covered under the source category and improve reporting to the GHGRP. We are proposing similar revisions to clarify definitions. For example, we are proposing to revise subpart A (General Provisions) to amend the definition of the term “Bulk” to address questions raised by certain suppliers as to whether imports or exports of GHGs in small containers are reportable to the GHGRP. The proposed revision is a clarification of the existing definition and would provide clarity regarding the size of containers that should be included in the reported supply. Finally, the EPA is proposing minor changes such as edits to fix typos, minor clarifications such as adding a missing word, and harmonizing changes to match other proposed revisions. For example, we are clarifying the 2022 Data Quality Improvements Proposal regarding proposed destruction and removal efficiency (DRE) and gamma factors in Tables I-16 and I-18 of subpart I (Electronics Manufacturing), respectively, to correct inadvertent errors in the relevant proposed regulatory text. We are also proposing to correct subpart AA (Pulp and Paper Manufacturing) at 40 CFR 98.276 to correct a reporting requirement that incorrectly refers to biogenic CH 4 and N 2 O. All proposed minor corrections and clarifications are reflected in the draft proposed redline regulatory text in the docket for this rulemaking (Docket Id. No. EPA-HQ-OAR-2019-0424). III. Proposed Amendments to Part 98 This section summarizes the specific substantive amendments proposed for each subpart, as generally described in section II of this preamble. The impacts of the proposed revisions are summarized in section VII of this preamble. A full discussion of the cost impacts for the proposed revisions may be found in the memorandum, Assessment of Burden Impacts for Proposed Supplemental Revisions for the Greenhouse Gas Reporting Rule, available in the docket for this rulemaking (Docket Id. No. EPA-HQ-OAR-2019-0424). A. Subpart A—General Provisions 1. Proposed Revisions to Global Warming Potentials in Table A-1 For the reasons described here and in section II.A of this preamble, we are proposing to revise Table A-1 to subpart A of part 98 (General Provisions) to update the GWP values of certain GHGs to reflect GWPs from Table 8.A.1 of AR5 and, for certain GHGs that do not have GWPs listed in AR5, to adopt GWP values from AR6. We are also proposing to add default GWPs for two new fluorinated GHG groups, to slightly modify an existing GHG group, and to update the default GWPs for all the existing fluorinated GHG groups. The chemical-specific GWP values currently in Table A-1 are drawn both from AR4 and, for multiple GHGs that do not have GWPs listed in AR4, from AR5. The current GWPs drawn from AR4 would be updated to values from AR5, while the current GWPs drawn from AR5 would remain the same. AR6 GWPs would be added for GHGs that do not have GWPs listed in AR5. Under the current rule, default GWPs are applied to GHGs that do not have GWPs listed in AR5 based on the fluorinated GHG group to which they belong. By proposing (1) to adopt (or maintain) AR5 GWPs for GHGs that have GWPs listed in AR5, and (2) to adopt AR6 GWPs for GHGs that do not have GWPs listed in AR5, we are taking the approach to establishing and updating GWPs that we have taken since the beginning of the GHGRP. That is, for GHGs with GWPs listed in the IPCC Assessment Report that the parties to the UNFCCC have agreed to use as the source of GWPs, we are proposing to use the GWPs in the agreed-upon Assessment Report to maintain consistency with the Inventory and other analyses. For GHGs that do not have GWPs listed in the agreed-upon Assessment Report, but that do have GWPs listed in a more recent IPCC Assessment Report, we are proposing to use the GWPs in the most recent report to increase the accuracy of the calculations and reporting under part 98. Where the UNFCCC-referenced Assessment Report does not include a GWP for a GHG, adopting the GWP from a more recent Assessment Report does not introduce inconsistency with Inventory reporting. In fact, as noted in the 2014 Fluorinated GHG Final Rule updating GWPs, adopting GWPs in the most recent Scientific Assessment Report would facilitate U.S. reporting under the UNFCCC Reporting Guidelines, which state: “Annex I Parties are strongly encouraged to also report emissions and removals of additional GHGs, such as hydrofluoroethers (HFEs), perfluoropolyethers (PFPEs), and other gases for which 100-year global warming potential values are available from the IPCC but have not yet been adopted by the [Conference of the Parties to the UNFCCC].” 18 18 See Decision 24, CP.19 at https://unfccc.int/resource/docs/2013/cop19/eng/10a03.pdf. Specifically, the first set of GWPs adopted under part 98 in 2009 consisted of (1) GWPs from the SAR for GHGs that had GWPs listed in the SAR (consistent with the UNFCCC reporting guidelines in effect at the time) and (2) GWPs from AR4 (the most recent IPCC Assessment Report available at the time) for GHGs that did not have GWPs listed in the SAR. 19 The second set of GWPs adopted under part 98, in 2013 and 2014, consisted of (1) GWPs from AR4 (consistent with the UNFCCC reporting guidelines going into effect at the time), and (2) GWPs from AR5 (the most recent IPCC Assessment Report available at the time) for GHGs that did not have GWPs listed in AR4. 19 Mandatory Reporting of Greenhouse Gases, proposed pule published on April 10, 2009 (74 FR 16453). Two decisions by the parties to the UNFCCC require countries to use the AR5 values from Table 8.A.1 for their Inventories and other reporting, beginning with the reports due in 2024. Decision 18/CMA.1, annex, paragraph 37 (December, 2018) reads, “Each Party shall use the 100-year time-horizon global warming potential (GWP) values from the IPCC Fifth Assessment Report, or 100-year time-horizon GWP values from a subsequent IPCC assessment report as agreed upon by the [Conference of the Parties serving as the meeting of the Parties to the Paris Agreement] (CMA), to report aggregate emissions and removals of GHGs, expressed in CO 2 eq.” Decision 5/CMA.3, paragraph 25 (November, 2021) reads, “the 100-year time-horizon global warming potential values referred to in decision 18/CMA.1, annex, paragraph 37, shall be those listed in Table 8.A.1 of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, excluding the value for fossil methane.” 20 20 Refer to https://unfccc.int/. The second decision, specifying that Parties must use the GWP values in Table 8.A.1 of AR5, excluding the value for “fossil methane,” was important for two reasons. First, AR5 includes two tables of GWPs. Table 8.A.1 includes GWPs that reflect the climate-carbon feedbacks of CO 2 but not the GHG whose GWP is being evaluated, while the other table includes GWPs that reflect the climate-carbon feedbacks of both CO 2 and the GHG whose GWP is being evaluated. (The same GHGs are in both tables.) Second, for methane, AR5 includes two GWP values in each table. In each table, one methane GWP accounts for the influence of CO 2 produced by the oxidation of methane (the value for “fossil” methane) and one methane GWP does not account for the influence of CO 2 produced by the oxidation of methane. Consistent with the 2021 UNFCCC decision, we are proposing to use (1) for GHGs with GWPs in AR5, the AR5 GWP values in Table 8.A.1 (that reflect the climate-carbon feedbacks of CO 2 but not the GHG whose GWP is being evaluated), and (2) for methane, the GWP that is not the GWP for fossil methane in Table 8.A.1 ( i.e., the GWP for methane that does not reflect either the climate-carbon feedbacks for methane or the atmospheric CO 2 that would result from the oxidation of methane in the atmosphere). In addition to maintaining consistency with recent UNFCCC decisions, using a single GWP for methane that does not reflect the CO 2 oxidation product would be consistent with prior IPCC practice, avoid the potential for double counting, and reduce complexity in accounting. 21 21 Paragraph 52 of the annex to 18/CMA.1 encourages parties to the UNFCCC to report indirect CO 2 emissions separately: “Each Party may report indirect CO2 from the atmospheric oxidation of CH4, CO and NMVOCs. For Parties that decide to report indirect CO2, the national totals shall be presented with and without indirect CO 2 .” Refer to https://unfccc.int/. Using the fossil methane GWP, which incorporates the impact of the indirect CO 2 , would double count those emissions. As noted above, we are also proposing to adopt AR6 GWPs for 31 GHGs that have GWPs listed in AR6 but not AR5. All of these are fluorinated GHGs. Currently, default GWPs based on each GHG's fluorinated GHG group are applied to these GHGs. Each default value reflects the average of the known GWPs of the GHGs in a group of chemically similar fluorinated GHGs. While the default value is expected to be an unbiased estimate of the GWPs of other fluorinated GHGs in that group, it is not expected to be as accurate as a chemical-specific GWP for any given GHG, which reflects the radiative efficiency and atmospheric lifetime of that GHG. The chemical-specific GWPs in each group vary over a range. For example, the chemical-specific AR5 GWPs in each group show relative standard deviations between 30 and 170 percent, depending on the group. Thus, using chemical-specific GWPs instead of default values would better reflect the atmospheric impacts of these gases. The AR6 GWPs reflect the climate-carbon feedbacks for the GHG whose GWP is being evaluated, while the AR5 GWPs that we are proposing to adopt (from Table 8.A.1) do not. GWPs that reflect the climate-carbon feedbacks for the GHG whose GWP is being evaluated are slightly larger than GWPs that do not. Thus, this difference could potentially result in over-weighting the atmospheric impacts of GHGs whose GWPs are drawn from AR6 relative to GHGs whose GWPs are drawn from Table 8.A.1 of AR5. However, our analysis indicates that using chemical-specific GWPs will lead to more accurate estimates, even if there are some inconsistencies among those GWPs. 22 In AR5, reflecting climate-carbon feedbacks for the GHG whose GWP is being evaluated results in an increase in the evaluated GWP of 11 to 22 percent, with the higher fractional increase being associated with shorter-lived gases with lower GWPs. 23 In contrast, using default GWPs based on AR5 rather than chemical-specific GWPs from AR6 would result in overestimating GWPs by as much as 3,000 (equivalent to a relative error of 1,200 percent) and underestimating GWPs by as much as 5,000 (equivalent to a relative error of −35 percent), with over- and underestimates averaging 1,200 and 950 respectively (and relative errors averaging 770 percent and −60 percent, respectively). 24 Overall, these potential errors are substantially larger than the differences between GWPs that do and do not reflect climate-carbon feedbacks for the GHGs whose GWPs were evaluated. 22 See the memorandum, Proposed Updates to Chemical-Specific and Default GWPs for the Greenhouse Gas Reporting Rule, available in the docket for this rulemaking (Docket Id. No. EPA-HQ-OAR-2019-0424). 23 The authors of AR6 estimated smaller impacts from climate-carbon feedbacks, meaning that the difference between accounting and not accounting for them is likely smaller than 11 to 22 percent. (See AR6, Chapter 7, page 121.) 24 To avoid skewing the results with inconsequential differences, instances where the default GWP would differ from the chemical-specific GWP by less than one were excluded from the analysis. In all these cases, the default GWP was one. Table 2 of this preamble lists the GHGs whose GWP values we are proposing to revise, along with the GWP values currently listed in Table A-1 and the proposed revised GWP values based on either AR5 or AR6. Additional information regarding the EPA's rationale for the proposed GWPs may be found in the memorandum, Proposed Updates to Chemical-Specific and Default GWPs for the Greenhouse Gas Reporting Rule, in the docket for this rulemaking, (Docket Id. No. EPA-HQ-OAR-2019-0424). Table 2—Proposed Revised Chemical-Specific GWPs for Compounds in Table A-1 Name CAS No. Chemical formula Current global warming potential (100 yr.) Proposed global warming potential (100 yr.) Chemical-Specific GWPs Carbon dioxide 124-38-9 CO 2 1 1 Methane 74-82-8 CH 4 25 28 Nitrous oxide 10024-97-2 N 2 O 298 265 Fully Fluorinated GHGs Sulfur hexafluoride 2551-62-4 SF 6 22,800 23,500 Trifluoromethyl sulphur pentafluoride 373-80-8 SF 5 CF 3 17,700 17,400 Nitrogen trifluoride 7783-54-2 NF 3 17,200 16,100 PFC-14 (Perfluoromethane) 75-73-0 CF 4 7,390 6,630 PFC-116 (Perfluoroethane) 76-16-4 C 2 F 6 12,200 11,100 PFC-218 (Perfluoropropane) 76-19-7 C 3 F 8 8,830 8,900 Perfluorocyclopropane 931-91-9 c-C 3 F 6 17,340 9,200 PFC-3-1-10 (Perfluorobutane) 355-25-9 C 4 F 10 8,860 9,200 PFC-318 (Perfluorocyclobutane) 115-25-3 c-C 4 F 8 10,300 9,540 Perfluorotetrahydrofuran 773-14-8 c-C 4 F 8 O * 10,000 13,900 PFC-4-1-12 (Perfluoropentane) 678-26-2 C 5 F 12 9,160 8,550 PFC-5-1-14 (Perfluorohexane, FC-72) 355-42-0 C 6 F 14 9,300 7,910 PFC-6-1-12 335-57-9 C 7 F 16 ; CF 3 (CF 2 ) 5 CF 3 7,820 7,820 PFC-7-1-18 307-34-6 C 8 F 18 ; CF 3 (CF 2 ) 6 CF 3 7,620 7,620 PFC-9-1-18 306-94-5 C 10 F 18 7,500 7,190 PFPMIE (HT-70) NA CF 3 OCF(CF 3 )CF 2 OCF 2 OCF 3 10,300 9,710 Perfluorodecalin (cis) 60433-11-6 Z-C 10 F 18 7,236 7,240 Perfluorodecalin (trans) 60433-12-7 E-C 10 F 18 6,288 6,290 Perfluorotriethylamine 359-70-6 N(C 2 F 5 ) 3 * 10,000 10,300 Perfluorotripropylamine 338-83-0 N(CF 2 CF 2 CF 3 ) 3 * 10,000 9,030 Perfluorotributylamine 311-89-7 N(CF 2 CF 2 CF 2 CF 3 ) 3 * 10,000 8,490 Perfluorotripentylamine 338-84-1 N(CF 2 CF 2 CF 2 CF 2 CF 3 ) 3 * 10,000 7,260 Saturated Hydrofluorocarbons (HFCs) With Two or Fewer Carbon-Hydrogen Bonds (4s,5s)-1,1,2,2,3,3,4,5-octafluorocyclopentane 158389-18-5 trans-cyc (-CF 2 CF 2 CF 2 CHFCHF-) * 3,700 258 HFC-23 75-46-7 CHF 3 14,800 12,400 HFC-32 75-10-5 CH 2 F 2 675 677 HFC-125 354-33-6 C 2 HF 5 3,500 3,170 HFC-134 359-35-3 C 2 H 2 F 4 1,100 1,120 HFC-134a 811-97-2 CH 2 FCF 3 1,430 1,300 HFC-227ca 2252-84-8 CF 3 CF 2 CHF 2 2,640 2,640 HFC-227ea 431-89-0 C 3 HF 7 3,220 3,350 HFC-236cb 677-56-5 CH 2 FCF 2 CF 3 1,340 1,210 HFC-236ea 431-63-0 CHF 2 CHFCF 3 1,370 1,330 HFC-236fa 690-39-1 C 3 H 2 F 6 9,810 8,060 HFC-329p 375-17-7 CHF 2 CF 2 CF 2 CF 3 2,360 2,360 HFC-43-10mee 138495-42-8 CF 3 CFHCFHCF 2 CF 3 1,640 1,650 Saturated Hydrofluorocarbons (HFCs) With Three or More Carbon-Hydrogen Bonds 1,1,2,2,3,3-hexafluorocyclopentane 123768-18-3 cyc (-CF 2 CF 2 CF 2 CH 2 CH 2 -) * 930 120 1,1,2,2,3,3,4-heptafluorocyclopentane 15290-77-4 cyc (-CF 2 CF 2 CF 2 CHFCH 2 -) * 930 231 HFC-41 593-53-3 CH 3 F 92 116 HFC-143 430-66-0 C 2 H 3 F 3 353 328 HFC-143a 420-46-2 C 2 H 3 F 3 4,470 4,800 HFC-152 624-72-6 CH 2 FCH 2 F 53 16 HFC-152a 75-37-6 CH 3 CHF 2 124 138 HFC-161 353-36-6 CH 3 CH 2 F 12 4 HFC-245ca 679-86-7 C 3 H 3 F 5 693 716 HFC-245cb 1814-88-6 CF 3 CF 2 CH 3 4,620 4,620 HFC-245ea 24270-66-4 CHF 2 CHFCHF 2 235 235 HFC-245eb 431-31-2 CH 2 FCHFCF 3 290 290 HFC-245fa 460-73-1 CHF 2 CH 2 CF 3 1,030 858 HFC-263fb 421-07-8 CH 3 CH 2 CF 3 76 76 HFC-272ca 420-45-1 CH 3 CF 2 CH 3 144 144 HFC-365mfc 406-58-6 CH 3 CF 2 CH 2 CF 3 794 804 Saturated Hydrofluoroethers (HFEs) and Hydrochlorofluoroethers (HCFEs) With One Carbon-Hydrogen Bond HFE-125 3822-68-2 CHF 2 OCF 3 14,900 12,400 HFE-227ea 2356-62-9 CF 3 CHFOCF 3 1,540 6,450 HFE-329mcc2 134769-21-4 CF 3 CF 2 OCF 2 CHF 2 919 3,070 HFE-329me3 428454-68-6 CF 3 CFHCF 2 OCF 3 4,550 4,550 1,1,1,2,2,3,3-Heptafluoro-3-(1,2,2,2-tetrafluoroethoxy)-propane 3330-15-2 CF 3 CF 2 CF 2 OCHFCF 3 6,490 6,490 Saturated HFEs and HCFEs With Two Carbon-Hydrogen Bonds HFE-134 (HG-00) 1691-17-4 CHF 2 OCHF 2 6,320 5,560 HFE-236ca 32778-11-3 CHF 2 OCF 2 CHF 2 4,240 4,240 HFE-236ca12 (HG-10) 78522-47-1 CHF 2 OCF 2 OCHF 2 2,800 5,350 HFE-236ea2 (Desflurane) 57041-67-5 CHF 2 OCHFCF 3 989 1,790 HFE-236fa 20193-67-3 CF 3 CH 2 OCF 3 487 979 HFE-338mcf2 156053-88-2 CF 3 CF 2 OCH 2 CF 3 552 929 HFE-338mmz1 26103-08-2 CHF 2 OCH(CF 3 ) 2 380 2,620 HFE-338pcc13 (HG-01) 188690-78-0 CHF 2 OCF 2 CF 2 OCHF 2 1,500 2,910 HFE-43-10pccc (H-Galden 1040x, HG-11) E1730133 CHF 2 OCF 2 OC 2 F 4 OCHF 2 1,870 2,820 HCFE-235ca2 (Enflurane) 13838-16-9 CHF 2 OCF 2 CHFCl 583 583 HCFE-235da2 (Isoflurane) 26675-46-7 CHF 2 OCHClCF 3 350 491 HG-02 205367-61-9 HF 2 C-(OCF 2 CF 2 ) 2 -OCF 2 H 3,825 2,730 HG-03 173350-37-3 HF 2 C-(OCF 2 CF 2 ) 3 -OCF 2 H 3,670 2,850 HG-20 249932-25-0 HF 2 C-(OCF 2 ) 2 -OCF 2 H 5,300 5,300 HG-21 249932-26-1 HF 2 C-OCF 2 CF 2 OCF 2 OCF 2 O-CF 2 H 3,890 3,890 HG-30 188690-77-9 HF 2 C-(OCF 2 ) 3 -OCF 2 H 7,330 7,330 1,1,3,3,4,4,6,6,7,7,9,9,10,10,12,12,13,13,15,15-eicosafluoro-2,5,8,11,14-Pentaoxapentadecane 173350-38-4 HCF 2 O(CF 2 CF 2 O) 4 CF 2 H 3,630 3,630 1,1,2-Trifluoro-2-(trifluoromethoxy)-ethane 84011-06-3 CHF 2 CHFOCF 3 1,240 1,240 Trifluoro(fluoromethoxy)methane 2261-01-0 CH 2 FOCF 3 751 751 Saturated HFEs and HCFEs With Three or More Carbon-Hydrogen Bonds HFE-143a 421-14-7 CH 3 OCF 3 756 523 HFE-245cb2 22410-44-2 CH 3 OCF 2 CF 3 708 654 HFE-245fa1 84011-15-4 CHF 2 CH 2 OCF 3 286 828 HFE-245fa2 1885-48-9 CHF 2 OCH 2 CF 3 659 812 HFE-254cb2 425-88-7 CH 3 OCF 2 CHF 2 359 301 HFE-263fb2 460-43-5 CF 3 CH 2 OCH 3 11 1 HFE-263m1; R-E-143a 690-22-2 CF 3 OCH 2 CH 3 29 29 HFE-347mcc3 (HFE-7000) 375-03-1 CH 3 OCF 2 CF 2 CF 3 575 530 HFE-347mcf2 171182-95-9 CF 3 CF 2 OCH 2 CHF 2 374 854 HFE-347mmy1 22052-84-2 CH 3 OCF(CF 3 ) 2 343 363 HFE-347mmz1 (Sevoflurane) 28523-86-6 (CF 3 ) 2 CHOCH 2 F 216 216 HFE-347pcf2 406-78-0 CHF 2 CF 2 OCH 2 CF 3 580 889 HFE-356mec3 382-34-3 CH 3 OCF 2 CHFCF 3 101 387 HFE-356mff2 333-36-8 CF 3 CH 2 OCH 2 CF 3 17 17 HFE-356mmz1 13171-18-1 (CF 3 ) 2 CHOCH 3 27 14 HFE-356pcc3 160620-20-2 CH 3 OCF 2 CF 2 CHF 2 110 413 HFE-356pcf2 50807-77-7 CHF 2 CH 2 OCF 2 CHF 2 265 719 HFE-356pcf3 35042-99-0 CHF 2 OCH 2 CF 2 CHF 2 502 446 HFE-365mcf2 22052-81-9 CF 3 CF 2 OCH 2 CH 3 58 58 HFE-365mcf3 378-16-5 CF 3 CF 2 CH 2 OCH 3 11 0.99 HFE-374pc2 512-51-6 CH 3 CH 2 OCF 2 CHF 2 557 627 HFE-449s1 (HFE-7100) Chemical blend 163702-07-6 C 4 F 9 OCH 3 297 421 163702-08-7 (CF 3 ) 2 CFCF 2 OCH 3 HFE-569sf2 (HFE-7200) Chemical blend 163702-05-4 C 4 F 9 OC 2 H 5 59 57 163702-06-5 (CF 3 ) 2 CFCF 2 OC 2 H 5 HFE-7300 132182-92-4 (CF 3 ) 2 CFCFOC 2 H 5 CF 2 CF 2 CF 3 * 270 405 HFE-7500 297730-93-9 n-C 3 F 7 CFOC 2 H 5 CF(CF 3 ) 2 * 270 13 HG′-01 73287-23-7 CH 3 OCF 2 CF 2 OCH 3 222 222 HG′-02 485399-46-0 CH 3 O(CF 2 CF 2 O) 2 CH 3 236 236 HG′-03 485399-48-2 CH 3 O(CF 2 CF 2 O) 3 CH 3 221 221 Difluoro(methoxy)methane 359-15-9 CH 3 OCHF 2 144 144 2-Chloro-1,1,2-trifluoro-1-methoxyethane 425-87-6 CH 3 OCF 2 CHFCl 122 122 1-Ethoxy-1,1,2,2,3,3,3-heptafluoropropane 22052-86-4 CF 3 CF 2 CF 2 OCH 2 CH 3 61 61 2-Ethoxy-3,3,4,4,5-pentafluorotetrahydro-2,5-bis[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-furan 920979-28-8 C 12 H 5 F 19 O 2 56 56 1-Ethoxy-1,1,2,3,3,3-hexafluoropropane 380-34-7 CF 3 CHFCF 2 OCH 2 CH 3 23 23 Fluoro(methoxy)methane 460-22-0 CH 3 OCH 2 F 13 13 1,1,2,2-Tetrafluoro-3-methoxy-propane; Methyl 2,2,3,3-tetrafluoropropyl ether 60598-17-6 CHF 2 CF 2 CH 2 OCH 3 0.5 0.49 1,1,2,2-Tetrafluoro-1-(fluoromethoxy)ethane 37031-31-5 CH 2 FOCF 2 CF 2 H 871 871 Difluoro(fluoromethoxy)methane 461-63-2 CH 2 FOCHF 2 617 617 Fluoro(fluoromethoxy)methane 462-51-1 CH 2 FOCH 2 F 130 130 Saturated Chlorofluorocarbons (CFCs) E-R316c 3832-15-3 trans-cyc (-CClFCF 2 CF 2 CClF-) * 2000 4,230 Z-R316c 3934-26-7 cis-cyc (-CClFCF 2 CF 2 CClF-) * 2000 5,660 Fluorinated Formates Trifluoromethyl formate 85358-65-2 HCOOCF 3 588 588 Perfluoroethyl formate 313064-40-3 HCOOCF 2 CF 3 580 580 1,2,2,2-Tetrafluoroethyl formate 481631-19-0 HCOOCHFCF 3 470 470 Perfluorobutyl formate 197218-56-7 HCOOCF 2 CF 2 CF 2 CF 3 392 392 Perfluoropropyl formate 271257-42-2 HCOOCF 2 CF 2 CF 3 376 376 1,1,1,3,3,3-Hexafluoropropan-2-yl formate 856766-70-6 HCOOCH(CF 3 ) 2 333 333 2,2,2-Trifluoroethyl formate 32042-38-9 HCOOCH 2 CF 3 33 33 3,3,3-Trifluoropropyl formate 1344118-09-7 HCOOCH 2 CH 2 CF 3 17 17 Fluorinated Acetates Methyl 2,2,2-trifluoroacetate 431-47-0 CF 3 COOCH 3 52 52 1,1-Difluoroethyl 2,2,2-trifluoroacetate 1344118-13-3 CF 3 COOCF 2 CH 3 31 31 Difluoromethyl 2,2,2-trifluoroacetate 2024-86-4 CF 3 COOCHF 2 27 27 2,2,2-Trifluoroethyl 2,2,2-trifluoroacetate 407-38-5 CF 3 COOCH 2 CF 3 7 7 Methyl 2,2-difluoroacetate 433-53-4 HCF 2 COOCH 3 3 3 Perfluoroethyl acetate 343269-97-6 CH 3 COOCF 2 CF 3 2.1 2 Trifluoromethyl acetate 74123-20-9 CH 3 COOCF 3 2.0 2 Perfluoropropyl acetate 1344118-10-0 CH 3 COOCF 2 CF 2 CF 3 1.8 2 Perfluorobutyl acetate 209597-28-4 CH 3 COOCF 2 CF 2 CF 2 CF 3 1.6 2 Ethyl 2,2,2-trifluoroacetate 383-63-1 CF 3 COOCH 2 CH 3 1.3 1 Carbonofluoridates Methyl carbonofluoridate 1538-06-3 FCOOCH 3 95 95 1,1-Difluoroethyl carbonofluoridate 1344118-11-1 FCOOCF 2 CH 3 27 27 Fluorinated Alcohols Other Than Fluorotelomer Alcohols Bis(trifluoromethyl)-methanol 920-66-1 (CF 3 ) 2 CHOH 195 182 2,2,3,3,4,4,5,5-Octafluorocyclopentanol 16621-87-7 cyc (-(CF 2 ) 4 CH(OH)-) 73 13 2,2,3,3,3-Pentafluoropropanol 422-05-9 CF 3 CF 2 CH 2 OH 42 19 2,2,3,3,4,4,4-Heptafluorobutan-1-ol 375-01-9 C 3 F 7 CH 2 OH 25 34 2,2,2-Trifluoroethanol 75-89-8 CF 3 CH 2 OH 20 20 2,2,3,4,4,4-Hexafluoro-1-butanol 382-31-0 CF 3 CHFCF 2 CH 2 OH 17 17 2,2,3,3-Tetrafluoro-1-propanol 76-37-9 CHF 2 CF 2 CH 2 OH 13 13 2,2-Difluoroethanol 359-13-7 CHF 2 CH 2 OH 3 3 2-Fluoroethanol 371-62-0 CH 2 FCH 2 OH 1.1 1.1 4,4,4-Trifluorobutan-1-ol 461-18-7 CF 3 (CH 2 ) 2 CH 2 OH 0.05 0.05 Non-Cyclic, Unsaturated Perfluorocarbons (PFCs) PFC-1114; TFE 116-14-3 CF 2 =CF 2 ; C 2 F 4 0.004 0.004 PFC-1216; Dyneon HFP 116-15-4 C 3 F 6 ; CF 3 CF=CF 2 0.05 0.05 Perfluorobut-2-ene 360-89-4 CF 3 CF=CFCF 3 1.82 1.82 Perfluorobut-1-ene 357-26-6 CF 3 CF 2 CF=CF 2 0.10 0.10 Perfluorobuta-1,3-diene 685-63-2 CF 2 =CFCF=CF 2 0.003 0.003 Non-Cyclic, Unsaturated Hydrofluorocarbons (HFCs) and Hydrochlorofluorocarbons (HCFCs) HFC-1132a; VF2 75-38-7 C 2 H 2 F 2 , CF 2 =CH 2 0.04 0.04 HFC-1141; VF 75-02-5 C 2 H 3 F, CH 2 =CHF 0.02 0.02 (E)-HFC-1225ye 5595-10-8 CF 3 CF=CHF(E) 0.06 0.06 (Z)-HFC-1225ye 5528-43-8 CF 3 CF=CHF(Z) 0.22 0.22 Solstice 1233zd(E) 102687-65-0 C 3 H 2 ClF 3 ; CHCl=CHCF 3 1.34 1.34 HCFO-1233zd(Z) 99728-16-2 (Z)-CF 3 CH=CHCl * 1 0.45 HFC-1234yf; HFO-1234yf 754-12-1 C 3 H 2 F 4 ; CF 3 CF=CH 2 0.31 0.31 HFC-1234ze(E) 1645-83-6 C 3 H 2 F 4 ; trans-CF 3 CH=CHF 0.97 0.97 HFC-1234ze(Z) 29118-25-0 C 3 H 2 F 4 ; cis-CF 3 CH=CHF; CF 3 CH=CHF 0.29 0.29 HFC-1243zf; TFP 677-21-4 C 3 H 3 F 3 , CF 3 CH=CH 2 0.12 0.12 (Z)-HFC-1336 692-49-9 CF 3 CH=CHCF 3 (Z) 1.58 1.58 HFO-1336mzz(E) 66711-86-2 (E)-CF 3 CH=CHCF 3 * 1 18 HFC-1345zfc 374-27-6 C 2 F 5 CH=CH 2 0.09 0.09 HFO-1123 359-11-5 CHF=CF 2 * 1 0.005 HFO-1438ezy(E) 14149-41-8 (E)-(CF 3 ) 2 CFCH=CHF * 1 8.2 HFO-1447fz 355-08-8 CF 3 (CF 2 ) 2 CH=CH 2 * 1 0.24 Capstone 42-U 19430-93-4 C 6 H 3 F 9 , CF 3 (CF 2 ) 3 CH=CH 2 0.16 0.16 Capstone 62-U 25291-17-2 C 8 H 3 F 13 , CF 3 (CF 2 ) 5 CH=CH 2 0.11 0.11 Capstone 82-U 21652-58-4 C 10 H 3 F 17 , CF 3 (CF 2 ) 7 CH=CH 2 0.09 0.09 (e)-1-chloro-2-fluoroethene 460-16-2 (E)-CHCl=CHF * 1 0.004 3,3,3-trifluoro-2-(trifluoromethyl)prop-1-ene 382-10-5 (CF 3 ) 2 C=CH 2 * 1 0.38 Non-Cyclic, Unsaturated CFCs CFC-1112 598-88-9 CClF=CClF * 1 0.13 CFC-1112a 79-35-6 CCl 2 =CF 2 * 1 0.021 Non-Cyclic, Unsaturated Halogenated Ethers PMVE; HFE-216 1187-93-5 CF 3 OCF=CF 2 0.17 0.17 Fluoroxene 406-90-6 CF 3 CH 2 OCH=CH 2 0.05 0.05 Methyl-perfluoroheptene-ethers N/A CH 3 OC 7 F 13 * 1 15 Non-Cyclic, Unsaturated Halogenated Esters Ethenyl 2,2,2-trifluoroacetate 433-28-3 CF 3 COOCH=CH 2 * 1 0.008 Prop-2-enyl 2,2,2-trifluoroacetate 383-67-5 CF 3 COOCH 2 CH=CH 2 * 1 0.007 Cyclic, Unsaturated HFCs and PFCs PFC C-1418 559-40-0 c-C 5 F 8 1.97 2 Hexafluorocyclobutene 697-11-0 cyc (-CF=CFCF 2 CF 2 -) * 1 126 1,3,3,4,4,5,5-heptafluorocyclopentene 1892-03-1 cyc (-CF 2 CF 2 CF 2 CF=CH-) * 1 45 1,3,3,4,4-pentafluorocyclobutene 374-31-2 cyc (-CH=CFCF 2 CF 2 -) * 1 92 3,3,4,4-tetrafluorocyclobutene 2714-38-7 cyc (-CH=CHCF 2 CF 2 -) * 1 26 Fluorinated Aldehydes 3,3,3-Trifluoro-propanal 460-40-2 CF 3 CH 2 CHO 0.01 0.01 Fluorinated Ketones Novec 1230 (perfluoro (2-methyl-3-pentanone)) 756-13-8 CF 3 CF 2 C(O)CF(CF 3 ) 2 0.1 0.1 1,1,1-trifluoropropan-2-one 421-50-1 CF 3 COCH 3 * 1 0.09 1,1,1-trifluorobutan-2-one 381-88-4 CF 3 COCH 2 CH 3 * 1 0.095 Fluorotelomer Alcohols 3,3,4,4,5,5,6,6,7,7,7-Undecafluoroheptan-1-ol 185689-57-0 CF 3 (CF 2 ) 4 CH 2 CH 2 OH 0.43 0.43 3,3,3-Trifluoropropan-1-ol 2240-88-2 CF 3 CH 2 CH 2 OH 0.35 0.35 3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-Pentadecafluorononan-1-ol 755-02-2 CF 3 (CF 2 ) 6 CH 2 CH 2 OH 0.33 0.33 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Nonadecafluoroundecan-1-ol 87017-97-8 CF 3 (CF 2 ) 8 CH 2 CH 2 OH 0.19 0.19 Fluorinated GHGs With Carbon-Iodine Bond(s) Trifluoroiodomethane 2314-97-8 CF 3 I 0.4 0.4 Remaining Fluorinated GHGs With Chemical-Specific GWPs Dibromodifluoromethane (Halon 1202) 75-61-6 CBr 2 F 2 231 231 2-Bromo-2-chloro-1,1,1-trifluoroethane (Halon-2311/Halothane) 151-67-7 CHBrClCF 3 41 41 Heptafluoroisobutyronitrile 42532-60-5 (CF 3 ) 2 CFCN * 2000 2,750 Carbonyl fluoride 353-50-4 COF 2 * 2000 ** 0.14 * Table A-1 does not include a chemical-specific value for this GHG; the value shown is the current default GWP for the fluorinated GHG group of which the GHG is currently a member. ** Proposed in 2022 Data Quality Improvements Proposal. We are also proposing to revise the default GWPs in Table A-1 by adding two new fluorinated GHG groups, modifying an existing group, and updating the existing default values to reflect the chemical-specific GWPs that we are proposing to adopt from AR5 and AR6. 25 The two new groups that we are proposing to add are for saturated chlorofluorocarbons (CFCs) and for cyclic forms of unsaturated halogenated compounds. We have not previously included a group for saturated CFCs because the GHGRP does not require reporting of most CFCs. The GHGRP definition of “fluorinated greenhouse gas” (that is itself referenced in the GHGRP definition of “greenhouse gas”) at 40 CFR 98.6, includes “sulfur hexafluoride (SF 6 ), nitrogen trifluoride (NF 3 ), and any fluorocarbon except for controlled substances as defined at 40 CFR part 82, subpart A and substances with vapor pressures of less than 1 mm of Hg absolute at 25 degrees C.” Although CFCs are fluorocarbons, most CFCs are defined as “controlled substances” under the EPA's ozone protection regulations at 40 CFR part 82, excluding them from GHGRP coverage. However, some CFCs are not defined as “controlled substances” under part 82 and are therefore reportable under the GHGRP. These include two saturated CFCs ((E)-1,2-dichlorohexafluorocyclobutane and (Z)-1,2-dichlorohexafluorocyclobutane) and two unsaturated CFCs (CFC 1112 and CFC 1112a) for which GWPs are provided in AR6. In the 2022 Data Quality Improvements Proposal, we have proposed to include unsaturated CFCs with unsaturated HFCs and PFCs in the current ninth fluorinated GHG group, which is assigned a default GWP of 1. (The unsaturated CFCs both have GWPs below 1.) The saturated CFCs have GWPs of 4,230 and 5,660 respectively, placing their proposed default GWP (4,900) between the updated default GWPs proposed for saturated HFCs with two or fewer carbon-hydrogen bonds (3,000) and for saturated HFEs and HCFEs with one carbon-hydrogen bond (6,600). Given the numerical differences between the GWP for the saturated CFC group and the GWPs for the other groups, as well as the chemical differences between CFCs, HFCs, and HFEs, we are proposing a separate group and separate default GWP for saturated CFCs. 25 In the 2014 Fluorinated GHG Final Rule, we established 12 default GWPs intended for fluorinated GHGs and fluorinated HTFs for which peer-reviewed GWPs were not available in AR4, AR5, or other sources. The default GWPs were calculated based on the average of the chemical-specific GWPs of the compounds in each fluorinated GHG group. Each fluorinated GHG group is composed of compounds with similar chemical structures, which have similar atmospheric lifetimes and GWPs. We are also proposing to establish a separate group for cyclic unsaturated halogenated compounds, specifically, for the cyclic forms of the following: unsaturated PFCs, unsaturated HFCs, unsaturated CFCs, unsaturated hydrochlorofluorocarbons (HCFCs), unsaturated bromofluorocarbons (BFCs), unsaturated bromochlorofluorocarbons (BCFCs), unsaturated hydrobromofluorocarbons (HBFCs), unsaturated hydrobromochlorofluorocarbons (HBCFCs), unsaturated halogenated ethers, and unsaturated halogenated esters. AR6 includes GWPs for five members of this set (all unsaturated HFCs or PFCs), ranging from 25.6 to 126. These GWPs are markedly larger than the GWPs for the non-cyclic unsaturated halogenated compounds currently in the ninth fluorinated GHG group, most of which are less than 1. 26 The default GWP proposed for the new group is 58, far higher than the value of 1 currently in effect for the unsaturated halogenated compounds in the ninth fluorinated GHG group. The new group would affect how the cyclic unsaturated halogenated compounds are classified for reporting under subparts A and L (Fluorinated Gas Production), and the corresponding default GWP would be applied to cyclic unsaturated halogenated compounds that do not have chemical-specific GWPs listed in AR5 or AR6. One cyclic unsaturated PFC that is currently included in the unsaturated group with the default GWP of 1, perfluorocyclopentene, would be moved into the new group for purposes of classification and calculation of the default GWP of the group. 27 26 This is true for both the AR5 and AR6 GWP values for the non-cyclic unsaturated compounds. Twenty-six of the 32 AR6 GWP values for these compounds fall under 1 while six fall above 1, with a maximum value of 18. 27 Perfluorocyclopentene is assigned GWP values of 2 and 78 in AR5 and AR6 respectively. The AR5 value was used in the calculation of the proposed default value for the cyclic unsaturated halogenated compounds. The proposed new and revised fluorinated GHG groups and their proposed new and revised GWPs are listed in Table 3 of this preamble. Table 3—Proposed Fluorinated GHG Groups and Default GWPs Fluorinated GHG group Current global warming potential (100 yr.) Proposed global warming potential (100 yr.) Fully fluorinated GHGs 10,000 9,200 Saturated hydrofluorocarbons (HFCs) with two or fewer carbon-hydrogen bonds 3,700 3,000 Saturated HFCs with three or more carbon-hydrogen bonds 930 840 Saturated hydrofluoroethers (HFEs) and hydrochlorofluoroethers (HCFEs) with one carbon-hydrogen bond 5,700 6,600 Saturated HFEs and HCFEs with two carbon-hydrogen bonds 2,600 2,900 Saturated HFEs and HCFEs with three or more carbon-hydrogen bonds 270 320 Saturated chlorofluorocarbons (CFCs) * 2,000 4,900 Fluorinated formates 350 350 Cyclic forms of the following: unsaturated perfluorocarbons (PFCs), unsaturated HFCs, unsaturated CFCs, unsaturated hydrochlorofluorocarbons (HCFCs), unsaturated bromofluorocarbons (BFCs), unsaturated bromochlorofluorocarbons (BCFCs), unsaturated hydrobromofluorocarbons (HBFCs), unsaturated hydrobromochlorofluorocarbons (HBCFCs), unsaturated halogenated ethers, and unsaturated halogenated esters ** 1 58 Fluorinated acetates, carbonofluoridates, and fluorinated alcohols other than fluorotelomer alcohols 30 25 Fluorinated aldehydes, fluorinated ketones, and non-cyclic forms of the following: unsaturated PFCs, unsaturated HFCs, unsaturated CFCs, unsaturated HCFCs, unsaturated BFCs, unsaturated BCFCs, unsaturated HBFCs, unsaturated HBCFCs, unsaturated halogenated ethers, and unsaturated halogenated esters 1 1 Fluorotelomer alcohols 1 1 Fluorinated GHGs with carbon-iodine bond(s) 1 1 Remaining fluorinated GHGs 2,000 1,800 * Based on current classification as “Other fluorinated GHGs.” ** Based on current classification as “Unsaturated perfluorocarbons (PFCs), unsaturated HFCs, unsaturated hydrochlorofluorocarbons (HCFCs), unsaturated halogenated ethers, unsaturated halogenated esters.” 2. Additional Proposed Revisions To Improve the Quality of Data Collected for Subpart A The EPA is proposing several revisions to subpart A to align with the proposed addition of subparts B (Energy Consumption), WW (Coke Calciners), XX (Calcium Carbide Production), YY (Caprolactam, Glyoxal, and Glyoxylic Acid Production), and ZZ (Ceramics Manufacturing), as described in sections II.B and IV of this preamble. First, we are proposing to revise 40 CFR 98.2(a)(1) through (3) to clarify that (1) direct emitters required to report under any source category listed in Tables A-3 or A-4 to subpart A of part 98 or stationary fuel combustion sources that meet the requirements of 40 CFR 98.2(a)(3), or required to resume reporting under §§ 98.2(i)(1), (2), or (3); and (2) that are not eligible to discontinue reporting under the provisions of 40 CFR 98.2(i)(1) through (3), would be required to cover metered purchased energy consumption (proposed subpart B) in their annual GHG report. As described in section IV.A of this preamble, direct emitters subject to part 98 would be required to report the annual quantity of electricity purchased and the annual quantity of thermal energy products purchased. Specifically, we are proposing to revise paragraphs 98.2(a)(1) through (3) to add that the annual GHG report must cover “energy consumption (subpart B of this part)” for facilities that are subject to direct emitter subparts. Additionally, we are proposing to revise the reporting requirements for the annual GHG report in 40 CFR 98.3(c)(4) to add a requirement for facilities to report the annual quantities of electricity purchased and the annual quantities of thermal energy products purchased. The proposed requirements ensure that facilities that report emissions of GHGs include total energy consumption data with the annual report. Additional information on proposed subpart B may be found in section IV.A of this preamble. Similarly, we are proposing to revise Table A-3 and Table A-4 to part 98 to clarify the reporting applicability for facilities included in the proposed new source categories described in sections IV.B through E of this preamble. Currently, a facility included in a source category listed in Table A-3 to subpart A of part 98 is subject to reporting under part 98. Source categories in Table A-3 are referred to as “all-in” source categories because reporting applies regardless of other source category or stationary fuel combustion emissions at the facility. The EPA's “all-in” approach generally applies for industries for which all facilities are emitters of a similar quantity, or where the EPA has determined it requires more data on certain industries to identify the parameters that influence GHG emissions from the source category. A facility that contains a source category listed in Table A-4 to subpart A of part 98 must report only if estimated annual emissions from all applicable source categories in Tables A-3 and Table A-4 of part 98 are 25,000 metric tons carbon dioxide equivalents (mtCO 2 e) or more. Source categories in Table A-4 are referred to as “threshold” source categories. The EPA's “threshold” approach generally applies when a source category contains emitters with a range in emissions quantity and the EPA wants to collect information from those facilities within the source category with larger total emissions from multiple process units or collocated source categories that emit larger levels of GHGs collectively, and not burden smaller emitters with a reporting obligation. We are proposing to revise Table A-3 to subpart A of part 98 to include new source categories for coke calciners (subpart WW), calcium carbide production (subpart XX), and caprolactam, glyoxal, and glyoxylic acid production (subpart YY). For coke calciners (subpart WW), as discussed in section IV.B of this preamble, we are proposing to include the source category as an “all-in” source category in Table A-3; based on the threshold analysis, most coke calciners are large emission sources that would be expected to exceed all of the thresholds considered, with no significant differences in the coverage of reporting facilities or the total U.S. emissions covered. As described in section IV.C of this preamble, we determined in a threshold analysis for the calcium carbide production source category that there is a single producer of calcium carbide in the United States whose known emissions would well exceed the 25,000 mtCO 2 e threshold currently referenced in 40 CFR 98.2(a)(2). Therefore, we are proposing to require that all facilities report in this source category, which would capture all U.S. emissions and avoid the need for the facility to calculate whether GHG emissions exceed the threshold value. The threshold analysis for the caprolactam, glyoxal, and glyoxylic acid production source category, as described in detail in section IV.D of this preamble, identified and estimated emissions for six facilities and concluded that setting a threshold of 25,000 mtCO 2 e would cover only half of the identified facilities but result in only a small difference in the total U.S. emissions that would be covered. After considering this information, we are proposing to add the caprolactam, glyoxal, and glyoxylic acid production source category as an “all-in” source category to Table A-3 to subpart A of part 98 to gather information from all applicable facilities, in order to account for the uncertainty in the data and assumptions used in the threshold analysis (see section IV.D.4 of this preamble for additional information). The proposed revisions to Table A-3 specify that new subparts WW, XX, and YY would become applicable in RY2025 (see section V of this preamble for additional details). 28 28 The proposed revisions to Table A-3 to subpart A also include the proposed source category for Geologic Sequestration of Carbon Dioxide with Enhanced Oil Recovery Using ISO 27916, proposed as subpart VV of part 98 in the 2022 Data Quality Improvements Proposal. Under this supplemental proposal, we are now proposing this rule, if finalized, would be applicable in RY2025. We are proposing to revise Table A-4 to subpart A of part 98 to include a new source category for ceramics production (subpart ZZ). As described in sections IV.E of this preamble, we conducted a threshold analysis for the ceramics production source category and determined the facilities in this source category have a broader range in emissions quantity. In order to collect information from those facilities within the source category with larger total emissions from multiple process units, or collocated source categories that emit larger levels of GHGs collectively, we are proposing to assign a threshold of 25,000 mtCO 2 e. For ceramics production (subpart ZZ), we are proposing that part 98 would apply to certain ceramics production processes that exceed a minimum production level ( i.e., annually consume at least 2,000 tons of carbonates or 20,000 tons of clay heated to a temperature sufficient to allow the calcination reaction to occur) and that exceed the 25,000 mtCO 2 e threshold. The proposed requirements would ensure coverage of large ceramics production facilities, while reducing the reporting burden for facilities with collocated source categories that may have already met GHGRP reporting thresholds under a different subpart of part 98 but may only have a small artisan-level ceramics process on site. We are proposing to revise Table A-4 such that new subpart ZZ would become applicable in RY2025. See section V of this preamble for additional details on the anticipated schedule for the proposed amendments. In keeping with the proposed revisions discussed in section II.A.1 of this preamble, we are proposing minor clarifications to the reporting and special provisions for best available monitoring methods in 40 CFR 98.3(k) and (l), which apply to owners or operators of facilities or suppliers that first become subject to any subpart of part 98 due to amendment to Table A-1 to subpart A. The current provisions, which were incorporated in the 2014 Fluorinated Gas Final Rule, require that these facilities or suppliers must start monitoring and collecting GHG data in compliance with the applicable subparts of part 98 to which the facility is subject “starting on January 1 of the year after the year during which the change in GWPs is published,” and provide for the use of best available monitoring methods, as applicable, for a period of three months “of the year after the year during which the change in GWPs is published.” Specifically, we are proposing to revise the term “published” to add “in the Federal Register as a final rulemaking.” The proposed changes would clarify the EPA's intent that the requirements apply to facilities or supplies that are first subject to the GHGRP in the year after the year the GWP is published as part of a final rule. For the reasons described in section II.E of this preamble, the EPA is proposing amendments to several defined terms in the General Provisions. First, we are proposing to revise the definition of “bulk” to provide clarity to the regulated community. Under 40 CFR 98.6 “bulk” is currently defined as “with respect to industrial GHG suppliers and CO 2 suppliers, [bulk] means the transfer of a product inside containers, including, but not limited to tanks, cylinders, drums, and pressure vessels.” Importers of industrial GHGs have had questions regarding this definition, particularly whether imports of motor vehicle air conditioner charging kits would fall within this definition given that the gas is in small cans in this case. The EPA notes that the current definition does not include any limit or restriction based on the size of the vessel in which the industrial GHG or CO 2 is transferred. Therefore, we maintain that the imports of industrial GHGs and CO 2 in small cans, such as motor vehicle air conditioner charging kits, would be reportable under subpart OO (Suppliers of Industrial Greenhouse Gases) based on our current definition of bulk. However, to improve clarity, the EPA is proposing to revise the definition of bulk to read that “ Bulk, with respect to industrial GHG suppliers and CO 2 suppliers, means a transfer of gas in any amount that is in a container for the transportation or storage of that substance such as cylinders, drums, ISO tanks, and small cans. An industrial gas or CO 2 that must first be transferred from a container to another container, vessel, or piece of equipment in order to realize its intended use is a bulk substance. An industrial GHG or CO 2 that is contained in a manufactured product such as electrical equipment, appliances, aerosol cans, or foams is not a bulk substance.” The revised definition would provide clarity to the regulated community regarding whether the import or export of gas in small containers would be considered “bulk.” The definition also provides additional details for suppliers to determine whether different types of imports or exports would fall within the definition. For example, this definition makes it clear that imports of motor vehicle air conditioner charging kits would qualify as imports of bulk substances, because the gas must first be transferred from a container ( i.e., the kit) to another container, vessel, or piece of equipment ( i.e., the motor vehicle) in order to realize its intended use ( i.e., comfort cooling). In addition, the revised definition makes it clear that gas contained in pre-charged equipment, appliances, foams, or aerosol cans would not qualify as bulk substances. This is consistent with the EPA's consideration of bulk in the past. In response to comments on the 2009 Final Rule (see “Mandatory Greenhouse Gas Reporting Rule: EPA's Response to Public Comments Volume No.: 40 Subpart OO—Suppliers of Industrial Greenhouse Gases, September 2009”), we stated that the “term `bulk' is intended to distinguish imports and exports in containers (cylinders, drums, etc.) from imports and exports in products; it is not intended to establish a minimum container or shipment size below which reporting would not be required.” After considering comments, the EPA did include provisions in the industrial gas supply reporting requirements (40 CFR 98.416) that exempt small shipments (those including less than 25 kilograms) from the import and export reporting requirements. However, a minimum shipment size does not imply a minimum container size. Finally, the revised definition would align the definition of “bulk” for industrial GHGs and CO 2 under the GHG Reporting Rule (40 CFR part 98) wi [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2023-10047. Public record. Not legal advice.