# National Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing Residual Risk and Technology Review > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2020-12776 ## Record - **Collection:** Federal Register - **Document type:** Rule - **Published:** August 12, 2020 - **Citation:** 85 FR 49084 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 [EPA-HQ-OAR-2018-0746; FRL-10010-27-OAR] RIN 2060-AT85 National Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing Residual Risk and Technology Review AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: This action finalizes the residual risk and technology review (RTR) conducted for the Miscellaneous Organic Chemical Manufacturing source category regulated under national emission standards for hazardous air pollutants (NESHAP). The U.S. Environmental Protection Agency (EPA) is finalizing decisions concerning the RTR, including amendments pursuant to the technology review for equipment leaks and heat exchange systems, and also amendments pursuant to the risk review to specifically address ethylene oxide emissions from storage tanks, process vents, and equipment leaks. In addition, we are taking final action to correct and clarify regulatory provisions related to emissions during periods of startup, shutdown, and malfunction (SSM), including removing general exemptions for periods of SSM, adding work practice standards for periods of SSM where appropriate, and clarifying regulatory provisions for certain vent control bypasses. The EPA is also taking final action to add monitoring and operational requirements for flares that control ethylene oxide emissions and flares used to control emissions from processes that produce olefins and polyolefins; add provisions for electronic reporting of performance test results and other reports; and include other technical corrections to improve consistency and clarity. We estimate that these final amendments will reduce hazardous air pollutants (HAP) emissions from this source category by approximately 107 tons per year (tpy) and reduce ethylene oxide emissions from this source category by approximately 0.76 tpy. We also estimate that these final amendments will reduce excess emissions of HAP from flares that control ethylene oxide emissions and flares used to control emissions from processes that produce olefins and polyolefins by an additional 263 tpy. DATES: This final rule is effective on August 12, 2020. The incorporation by reference (IBR) of certain publications listed in the rule is approved by the Director of the Federal Register as of August 12, 2020. ADDRESSES: The EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2018-0746. All documents in the docket are listed on the https://www.regulations.gov/ website. Although listed, some information is not publicly available, e.g., Confidential Business Information or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available electronically through https://www.regulations.gov/. Out of an abundance of caution for members of the public and our staff, the EPA Docket Center and Reading Room was closed to public visitors on March 31, 2020, to reduce the risk of transmitting COVID-19. Our Docket Center staff will continue to provide remote customer service via email, phone, and webform. There is a temporary suspension of mail delivery to the EPA, and no hand deliveries are currently accepted. For further information and updates on EPA Docket Center services and the current status, please visit us online at https://www.epa.gov/dockets. FOR FURTHER INFORMATION CONTACT: For questions about this final action, contact Ms. Tegan Lavoie, Sector Policies and Programs Division (E-143-01), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-5110; and email address: lavoie.tegan@epa.gov. For specific information regarding the risk modeling methodology, contact Mr. Matthew Woody, Health and Environmental Impacts Division (C539-02), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-1535; and email address: woody.matthew@epa.gov. For information about the applicability of the NESHAP to a particular entity, contact Mr. John Cox, Office of Enforcement and Compliance Assurance, U.S. Environmental Protection Agency, WJC South Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460; telephone number: (202) 564-1395; and email address: cox.john@epa.gov. SUPPLEMENTARY INFORMATION: Preamble acronyms and abbreviations. We use multiple acronyms and terms in this preamble. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here: ACC American Chemistry Council AEGL acute exposure guideline level APCD air pollution control device AMEL Alternative means of emission limitation ANSI American National Standards Institute BAAQMD Bay Area Air Quality Management District Btu/scf British thermal unit per standard cubic foot CAA Clean Air Act CAP Chemical Accident Prevention CDX Central Data Exchange CEDRI Compliance and Emissions Data Reporting Interface CEMS continuous emissions monitoring systems CFR Code of Federal Regulations CRA Congressional Review Act EPA Environmental Protection Agency EPCRA Emergency Planning and Community Right-To-Know Act ERT Electronic Reporting Tool FID flame ionization detector FTIR fourier transfer infrared spectrometry gpm gallons per minute HAP hazardous air pollutant(s) HCl hydrochloric acid HES heat exchanger systems HI hazard index HON Hazardous Organic NESHAP HQ hazard quotient HRVOC highly reactive volatile organic compounds IBR incorporation by reference ICR Information Collection Request IRIS Integrated Risk Information System kg/yr kilograms per year km kilometers lb/yr pounds per year LDAR leak detection and repair LEL lower explosive limit MACT maximum achievable control technology MCPU miscellaneous organic chemical manufacturing process unit MIR maximum individual risk MON Miscellaneous Organic Chemical Manufacturing NESHAP NAICS North American Industry Classification System NEI National Emissions Inventory NESHAP national emission standards for hazardous air pollutants NHVcz net heating value of the combustion zone gas NRDC Natural Resources Defense Council NSPS new source performance standards NTTAA National Technology Transfer and Advancement Act OMB Office of Management and Budget PB-HAP hazardous air pollutants known to be persistent and bio-accumulative in the environment PDF portable document format PDH propane dehydrogenation PFTIR passive fourier transfer infrared spectrometry POM polycyclic organic matter ppm parts per million ppmv parts per million by volume ppmw parts per million by weight PRA Paperwork Reduction Act PRD pressure relief device(s) psig pounds per square inch gauge PSM Process Safety Management RACT reasonably available control technology REL reference exposure level RFA Regulatory Flexibility Act RTR residual risk and technology review SCAQMD South Coast Air Quality Management District SSM startup, shutdown, and malfunction SV screening value TAC Texas Administrative Code TCEQ Texas Commission on Environmental Quality the Court United States Court of Appeals for the District of Columbia Circuit TOC total organic compound TOSHI target organ-specific hazard index tpy tons per year TRI Toxics Release Inventory UMRA Unfunded Mandates Reform Act URE unit risk estimate VCS voluntary consensus standards VOC volatile organic compound(s) Background information. On December 17, 2019 (84 FR 69182), the EPA proposed revisions to the Miscellaneous Organic Chemical Manufacturing NESHAP (MON) based on our RTR. In this action, we are finalizing decisions and revisions for the rule. We summarize some of the more significant comments we timely received regarding the proposed rule and provide our responses in this preamble. A summary of all other public comments on the proposal and the EPA's responses to those comments is available in the Summary of Public Comments and Responses for the Risk and Technology Review for Miscellaneous Organic Chemical Manufacturing, in Docket ID No. EPA-HQ-OAR-2018-0746. A “tracked changes” version of the regulatory language that incorporates the changes in this action is available in the docket. Organization of this document. The information in this preamble is organized as follows: I. General Information A. Does this action apply to me? B. Where can I get a copy of this document and other related information? C. Judicial Review and Administrative Reconsideration II. Background A. What is the statutory authority for this action? B. What is the Miscellaneous Organic Chemical Manufacturing source category and how does the NESHAP regulate HAP emissions from the source category? C. What changes did we propose for the Miscellaneous Organic Chemical Manufacturing source category in our December 17, 2019, RTR proposal? III. What is included in this final rule? A. What are the final rule amendments based on the risk review for the Miscellaneous Organic Chemical Manufacturing source category? B. What are the final rule amendments based on the technology review for the Miscellaneous Organic Chemical Manufacturing source category? C. What are the final rule amendments pursuant to CAA section 112(d)(2) and (3) and 112(h) for the Miscellaneous Organic Chemical Manufacturing source category? D. What are the final rule amendments addressing emissions during periods of SSM? E. What other changes have been made to the NESHAP? F. What are the effective and compliance dates of the standards? IV. What is the rationale for our final decisions and amendments for the Miscellaneous Organic Chemical Manufacturing source category? A. Residual Risk Review for the Miscellaneous Organic Chemical Manufacturing Source Category B. Technology Review for the Miscellaneous Organic Chemical Manufacturing Source Category C. Amendments Pursuant to CAA section 112(d)(2) and (3) and 112(h) for the Miscellaneous Organic Chemical Manufacturing Source Category D. Amendments Addressing Emissions During Periods of SSM E. Other Amendments to the MACT Standards V. Summary of Cost, Environmental, and Economic Impacts and Additional Analyses Conducted A. What are the affected facilities? B. What are the air quality impacts? C. What are the cost impacts? D. What are the economic impacts? E. What are the benefits? F. What analysis of environmental justice did we conduct? G. What analysis of children's environmental health did we conduct? VI. Statutory and Executive Order Reviews A. Executive Orders 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review B. Executive Order 13771: Reducing Regulations and Controlling Regulatory Costs C. Paperwork Reduction Act (PRA) D. Regulatory Flexibility Act (RFA) E. Unfunded Mandates Reform Act (UMRA) F. Executive Order 13132: Federalism G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments H. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR Part 51 K. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations L. Congressional Review Act (CRA) I. General Information A. Does this action apply to me? Regulated entities. Categories and entities potentially regulated by this action are shown in Table 1 of this preamble. Table 1—NESHAP and Industrial Source Categories Affected by This Final Action NESHAP and Source Category NAICS 1 code Miscellaneous Organic Chemical Manufacturing 3251, 3252, 3253, 3254, 3255, 3256, and 3259, with several exceptions. 1 North American Industry Classification System. Table 1 of this preamble is not intended to be exhaustive, but rather to provide a guide for readers regarding entities likely to be affected by the final action for the source category listed. To determine whether your facility is affected, you should examine the applicability criteria in the appropriate NESHAP. If you have any questions regarding the applicability of any aspect of this NESHAP, please contact the appropriate person listed in the preceding FOR FURTHER INFORMATION CONTACT section of this preamble. B. Where can I get a copy of this document and other related information? In addition to being available in the docket, an electronic copy of this final action will also be available on the internet. Following signature by the EPA Administrator, the EPA will post a copy of this final action at: https://www.epa.gov/stationary-sources-air-pollution/miscellaneous-organic-chemical-manufacturing-national-emission. Following publication in the Federal Register , the EPA will post the Federal Register version and key technical documents at this same website. Additional information is available on the RTR website at https://www.epa.gov/stationary-sources-air-pollution/risk-and-technology-review-national-emissions-standards-hazardous. This information includes an overview of the RTR program and links to project websites for the RTR source categories. C. Judicial Review and Administrative Reconsideration Under Clean Air Act (CAA) section 307(b)(1), judicial review of this final action is available only by filing a petition for review in the United States Court of Appeals for the District of Columbia Circuit (the Court) by October 13, 2020. Under CAA section 307(b)(2), the requirements established by this final rule may not be challenged separately in any civil or criminal proceedings brought by the EPA to enforce the requirements. Section 307(d)(7)(B) of the CAA further provides that only an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment (including any public hearing) may be raised during judicial review. This section also provides a mechanism for the EPA to reconsider the rule if the person raising an objection can demonstrate to the Administrator that it was impracticable to raise such objection within the period for public comment or if the grounds for such objection arose after the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule. Any person seeking to make such a demonstration should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy to both the person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT section, and the Associate General Counsel for the Air and Radiation Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW, Washington, DC 20460. II. Background A. What is the statutory authority for this action? On March 13, 2017, the U.S. District Court for District of Columbia ordered the EPA to perform all acts or duties required by CAA section 112(f)(2) and CAA section 112(d)(6) for 20 source categories, including Miscellaneous Organic Chemical Manufacturing, within three years of the date of the court order (See California Communities Against Toxics, et al. v. Scott Pruitt, 241 F. Supp. 3d 199 (D.D.C. 2017)). On February 19, 2020, the U.S. District Court for District of Columbia granted the EPA an extension on the final rule deadline for the Miscellaneous Organic Chemical Manufacturing source category from March 13, 2020, to May 29, 2020. Section 112 of the CAA establishes a two-stage regulatory process to address emissions of HAP from stationary sources. In the first stage, we must identify categories of sources emitting one or more of the HAP listed in CAA section 112(b) and then promulgate technology-based NESHAP for those sources. “Major sources” are those that emit, or have the potential to emit, any single HAP at a rate of 10 tons per year (tpy) or more, or 25 tpy or more of any combination of HAP. For major sources, these standards are commonly referred to as maximum achievable control technology (MACT) standards and must reflect the maximum degree of emission reductions of HAP achievable (after considering cost, energy requirements, and non-air quality health and environmental impacts). In developing MACT standards, CAA section 112(d)(2) directs the EPA to consider the application of measures, processes, methods, systems, or techniques, including, but not limited to those that reduce the volume of or eliminate HAP emissions through process changes, substitution of materials, or other modifications; enclose systems or processes to eliminate emissions; collect, capture, or treat HAP when released from a process, stack, storage, or fugitive emissions point; are design, equipment, work practice, or operational standards; or any combination of the above. For MACT standards, the statute specifies certain minimum stringency requirements, which are referred to as MACT floor requirements, and which may not be based on cost considerations. See CAA section 112(d)(3). For new sources, the MACT floor cannot be less stringent than the emission control achieved in practice by the best-controlled similar source. The MACT standards for existing sources can be less stringent than standards for new sources, but they cannot be less stringent than the average emission limitation achieved by the best-performing 12 percent of existing sources in the category or subcategory (or the best-performing five sources for categories or subcategories with fewer than 30 sources). In developing MACT standards, we must also consider control options that are more stringent than the floor under CAA section 112(d)(2). We may establish standards more stringent than the floor, after consideration of the cost of achieving the emissions reductions, any non-air quality health and environmental impacts, and energy requirements. In the second stage of the regulatory process, the CAA requires the EPA to undertake two different analyses, which we refer to as the technology review and the residual risk review. Under the technology review, we must review the technology-based standards and revise them “as necessary (taking into account developments in practices, processes, and control technologies)” no less frequently than every 8 years, pursuant to CAA section 112(d)(6). Under the residual risk review, we must evaluate the risk to public health remaining after application of the technology-based standards and revise the standards, if necessary, to provide an ample margin of safety to protect public health or to prevent, taking into consideration costs, energy, safety, and other relevant factors, an adverse environmental effect. The residual risk review is required within 8 years after promulgation of the technology-based standards, pursuant to CAA section 112(f). In conducting the residual risk review, if the EPA determines that the current standards provide an ample margin of safety to protect public health, it is not necessary to revise the MACT standards pursuant to CAA section 112(f). 1 For more information on the statutory authority for this rule, see 84 FR 69182, December 17, 2019. 1 The Court has affirmed this approach of implementing CAA section 112(f)(2)(A): NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008) (“If EPA determines that the existing technology-based standards provide an 'ample margin of safety,' then the Agency is free to readopt those standards during the residual risk rulemaking.”). B. What is the Miscellaneous Organic Chemical Manufacturing source category and how does the NESHAP regulate HAP emissions from the source category? The EPA promulgated the current NESHAP, herein called the Miscellaneous Organic Chemical Manufacturing NESHAP (MON) on November 10, 2003 (68 FR 63852), and further amended the MON on July 1, 2005 (70 FR 38562), and July 14, 2006 (71 FR 40316). The standards are codified at 40 Code of Federal Regulations (CFR) part 63, subpart FFFF. The MON regulates HAP emissions from miscellaneous organic chemical manufacturing process units (MCPUs) located at major sources. An MCPU includes a miscellaneous organic chemical manufacturing process, as defined in 40 CFR 63.2550(i), and must meet the following criteria: (1) It manufactures any material or family of materials described in 40 CFR 63.2435(b)(1); (2) it processes, uses, or generates any of the organic HAP described in 40 CFR 63.2435(b)(2); and, (3) except for certain process vents that are part of a chemical manufacturing process unit, as identified in 40 CFR 63.100(j)(4), the MCPU is not an affected source or part of an affected source under another subpart of 40 CFR part 63. An MCPU also includes any assigned storage tanks and transfer racks; equipment in open systems that is used to convey or store water having the same concentration and flow characteristics as wastewater; and components such as pumps, compressors, agitators, pressure relief devices (PRDs), sampling connection systems, open-ended valves or lines, valves, connectors, and instrumentation systems that are used to manufacture any material or family of materials described in 40 CFR 63.2435(b)(1). Sources of HAP emissions regulated by the MON include the following: process vents, storage tanks, transfer racks, equipment leaks, wastewater streams, and heat exchange systems. As of November 6, 2018, there were 201 miscellaneous organic chemical manufacturing facilities identified and in operation and subject to the MON standards, herein referred to as “MON facilities.” This facility population count was developed using methods described in section II.C of the proposal preamble (84 FR 69182, December 17, 2019). A complete list of known MON facilities is available in Appendix 1 of the document, Residual Risk Assessment for the Miscellaneous Organic Chemical Manufacturing Source Category in Support of the 2019 Risk and Technology Review Proposed Rule, which is available in the docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0011). C. What changes did we propose for the Miscellaneous Organic Chemical Manufacturing source category in our December 17, 2019, RTR proposal? On December 17, 2019, the EPA published a proposed rule in the Federal Register for the MON, 40 CFR part 63, subpart FFFF, that took into consideration the RTR analyses (84 FR 69182). We proposed to find that the risks from the source category are unacceptable. We proposed to address risk by revising the MON pursuant to CAA section 112(f)(2) to require control of ethylene oxide emissions from process vents, storage tanks, and equipment “in ethylene oxide service.” 2 We also proposed that these control requirements would both achieve acceptable risks and provide an ample margin of safety to protect public health and more stringent standards are not necessary to prevent an adverse environmental effect. 2 For process vents, we proposed to define “in ethylene oxide service” to mean that each batch and continuous process vent in a process that, when uncontrolled, contains a concentration of greater than or equal to 1 ppmv undiluted ethylene oxide, and when combined, the sum of all these process vents would emit uncontrolled, undiluted ethylene oxide emissions greater than or equal to 5 lb/yr (2.27 kg/yr). For storage tanks of any capacity and vapor pressure, we proposed to define “in ethylene oxide service” to mean that the concentration of ethylene oxide of the stored liquid is greater than or equal to 1 part per million by weight (ppmw). We proposed that the exemptions for “vessels storing organic liquids that contain HAP only as impurities” and “pressure vessels designed to operate in excess of 204.9 kilopascals and without emissions to the atmosphere” listed in the definition of “storage tank” at 40 CFR 63.2550(i) do not apply for storage tanks in ethylene oxide service. For the ethylene oxide equipment leak provisions, we proposed to define “in ethylene oxide service” to mean any equipment that contains or contacts a fluid (liquid or gas) that is at least 0.1 percent by weight of ethylene oxide. For process vents, we proposed to either reduce emissions of ethylene oxide by (1) venting emissions through a closed-vent system to a control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight, to a concentration less than 1 part per million by volume (ppmv) for each process vent, or to less than 5 pounds per year (lb/yr) for all combined process vents; or (2) venting emissions through a closed-vent system to a flare meeting the proposed flare operating requirements. For storage tanks, we proposed to reduce emissions of ethylene oxide by either (1) venting emissions through a closed-vent system to a control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight or to a concentration less than 1 ppmv for each storage tank vent; or (2) venting emissions through a closed-vent system to a flare meeting the proposed flare operating requirements. We proposed removing the option to allow use of a design evaluation in lieu of performance testing to demonstrate compliance for both process vents and storage tanks in ethylene oxide service. We also proposed that owners or operators that choose to control emissions with a non-flare control device conduct an initial performance test on each control device in ethylene oxide service to verify performance at the required level of control, and we proposed conducting periodic performance testing on non-flare control devices in ethylene oxide service every 5 years. To reduce risks from leaking equipment in ethylene oxide service, we co-proposed two options, i.e., Control Option 1 and Control Option 2. In equipment leak co-proposed Control Option 1, we proposed that all light liquid pumps in ethylene oxide service be monitored monthly at a leak definition of 1,000 parts per million (ppm), and when a leak is detected, it be repaired as soon as practicable, but not later than 15 calendar days after it is detected. Additionally, under co-proposed Control Option 1, we proposed that the leak repair exemption available for pumps at 40 CFR 63.1026(b)(3), 40 CFR 63.163(c)(3), and 40 CFR 65.107(b)(3) would not apply to equipment in ethylene oxide service. Also, as part of co-proposed Control Option 1, we proposed that all gas/vapor and light liquid connectors in ethylene oxide service be monitored annually at a leak definition of 500 ppm, and when a leak is detected, it be repaired as soon as practicable, but not later than 15 calendar days after it is detected. In equipment leak co-proposed Control Option 2, we proposed that more stringent equipment leak standards would apply to the facilities with a maximum individual risk (MIR) greater than 100-in-1 million after imposition of the proposed standards for process vents and storage tanks, as determined by this risk analysis ( i.e., Lanxess Corporation and Huntsman Performance). For these two facilities, pumps in ethylene oxide service would be required to be leakless ( i.e., have zero emissions) and monitored annually to verify there are no emissions. Additionally, valves in ethylene oxide service would be required to either be leakless and monitored annually or not be leakless and be monitored quarterly. For pumps and valves in ethylene oxide service, we proposed that equipment is considered leaking if an instrument reading above background is found. Furthermore, at the two higher risk facilities with a MIR greater than 100-in-1 million, we proposed that connectors in ethylene oxide service would be monitored monthly at a leak definition of 100 ppm. We proposed that when a leak is detected it would be repaired as soon as practicable, but not later than 15 calendar days after it is detected, and a first attempt at repair be made no later than 5 calendar days after the leak is detected. As part of co-proposed Control Option 2, all other facilities with MON equipment in ethylene oxide service would be subject to the standards previously described in equipment leak co-proposed Control Option 1. In addition, pursuant to the technology review for the Miscellaneous Organic Chemical Manufacturing source category, we proposed that no revisions to the current standards are necessary for process vents, storage tanks, transfer racks, and wastewater streams; however, we did propose changes for equipment leaks and heat exchange systems. We proposed revisions to the equipment leak requirements, pursuant to CAA section 112(d)(6), to lower the leak definition for pumps in light liquid service at existing batch processes from 10,000 ppmv to 1,000 ppmv with monthly monitoring and clarify that you must initially monitor for leaks within 30 days after initial startup of the equipment. In addition, we proposed revisions to the heat exchange system requirements, pursuant to CAA section 112(d)(6), to require owners or operators to use the Modified El Paso Method and repair leaks of total strippable hydrocarbon concentration (as methane) in the stripping gas of 6.2 ppmv or greater. We also proposed the following amendments: • Revisions to the operating and monitoring requirements for flares that control ethylene oxide emissions, flares used to control emissions from processes that produce olefins and polyolefins, and providing the option for an owner or operator of a flare outside of this subset to choose to opt in to these revised requirements in lieu of complying with the current flare standards, pursuant to CAA section 112(d)(2) and (3); • Requirements and clarifications for periods of SSM and bypasses, including for PRD releases, bypass lines on closed vent systems, maintenance activities, and certain gaseous streams routed to a fuel gas system, pursuant to CAA section 112(d)(2) and (3); • Revisions to the SSM provisions of the MON (in addition to those related to vent control bypasses) in order to ensure that they are consistent with the Court decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008), which vacated two provisions that exempted source owners or operators from the requirement to comply with otherwise applicable CAA section 112(d) emission standards during periods of SSM; • A requirement for electronic submittal of performance test results and reports, performance evaluation reports, and compliance reports; • Clarifications to the requirements for nonregenerative adsorbers, and regenerative adsorbers that are regenerated offsite; • IBR of an alternative test method for EPA Method 18 (with caveats); • IBR of an alternative test method for EPA Method 101A and EPA Method 29 (portion for mercury only); • IBR of an alternative test method for EPA Method 624; • Use of an alternative test method for EPA Method 3B (for the manual procedures only and not the instrumental procedures); • Use of an alternative test method for EPA Method 320 (with caveats); and • Several minor editorial and technical changes in the subpart. III. What is included in this final rule? This action provides the EPA's final determinations pursuant to the RTR provisions of CAA section 112 for the Miscellaneous Organic Chemical Manufacturing source category and amends the MON based on those determinations. This action also finalizes other changes to the NESHAP, including adding requirements and clarifications for periods of SSM and bypasses; revising the operating and monitoring requirements for flares that control ethylene oxide emissions, flares used to control emissions from processes that produce olefins and polyolefins and allowing flares outside of this subset to comply with these amended flare requirements; adding provisions for electronic reporting of performance test results and reports, performance evaluation reports, and compliance reports; and other minor editorial and technical changes. This action also reflects several changes to the December 17, 2019, RTR proposal (84 FR 69182), in consideration of comments received during the public comment period as described in section IV of this preamble. A. What are the final rule amendments based on the risk review for the Miscellaneous Organic Chemical Manufacturing source category? This section describes the final amendments to the MON being promulgated pursuant to CAA section 112(f). Consistent with the proposal, the EPA determined that the risks for this source category under the current MACT provisions are unacceptable. When risks are unacceptable, the EPA must determine the emissions standards necessary to reduce risk to an acceptable level. As such, the EPA is promulgating final amendments to the MON pursuant to CAA section 112(f)(2) that require control of ethylene oxide for process vents, storage tanks, and equipment in ethylene oxide service, with some changes in the final rule due to comments received during the public comment period. As discussed in section IV.A of this preamble, implementation of these controls will reduce risk to an acceptable level that also provides an ample margin of safety to protect public health. For process vents in ethylene oxide service, the EPA is finalizing the requirement, as proposed, to either reduce emissions of ethylene oxide by (1) venting emissions through a closed-vent system to a control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight, to a concentration less than 1 ppmv for each process vent, or to less than 5 lb/yr for all combined process vents; or (2) venting emissions through a closed-vent system to a flare meeting the flare operating requirements discussed in sections IV.A.1 and IV.C.2 of the proposal preamble (84 FR 69182, December 17, 2019). However, based on comments received on the proposed rulemaking, we are revising the proposed definition of “in ethylene oxide service” for process vents by removing “undiluted” from the mass-based criteria and removing the phrase “anywhere in the process.” In the final rule, a process vent in ethylene oxide service means each batch and continuous process vent in a process that, when uncontrolled, contains a concentration of greater than or equal to 1 ppmv undiluted ethylene oxide, and when combined, the sum of all these process vents would emit uncontrolled, ethylene oxide emissions greater than or equal to 5 lb/yr [2.27 kilograms per year (kg/yr)]. In addition, based on comments received on the proposed rulemaking, we are revising the definitions of “batch process vent” and “continuous process vent” in the final rule to clarify that: (1) The existing 50 ppmv HAP and 200 lb/yr uncontrolled HAP emission cut-offs do not apply to batch process vents in ethylene oxide service; and (2) the existing 0.005 weight percent total organic HAP cut-off in 40 CFR 63.107(d) does not apply to continuous process vents in ethylene oxide service. For storage tanks in ethylene oxide service, we are finalizing a requirement, as proposed, to reduce emissions of ethylene oxide by either (1) venting emissions through a closed-vent system to a control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight or to a concentration less than 1 ppmv for each storage tank vent; or (2) venting emissions through a closed-vent system to a flare meeting the flare operating requirements discussed in sections IV.A.1 and IV.C.2 of the proposal preamble (84 FR 69182, December 17, 2019). However, based on comments received on the proposed rulemaking, we are revising the proposed definition of “in ethylene oxide service” for storage tanks by revising the concentration of ethylene oxide criteria to a 0.1 percent by weight threshold. In the final rule, a storage tank in ethylene oxide service means a storage tank of any capacity and vapor pressure storing a liquid that is at least 0.1 percent by weight of ethylene oxide. We are also finalizing, as proposed, that the exemptions for “vessels storing organic liquids that contain HAP only as impurities” and “pressure vessels designed to operate in excess of 204.9 kilopascals and without emissions to the atmosphere” listed in the definition of “storage tank” at 40 CFR 63.2550(i) do not apply for storage tanks in ethylene oxide service. Additionally, for both process vents in ethylene oxide service and storage tanks in ethylene oxide service, we are removing the option to allow use of a design evaluation in lieu of performance testing to demonstrate compliance to ensure that the required level of control is achieved, consistent with the proposal. We are also finalizing, as proposed, that after promulgation of the rule, owners or operators that choose to control emissions with a non-flare control device conduct an initial performance test according to 40 CFR 63.997 and 40 CFR 63.2450(g) on each existing control device in ethylene oxide service and on each newly installed control device in ethylene oxide service to verify performance at the required level of control. Subsequently, we are finalizing that owners or operators conduct periodic performance testing on non-flare control devices in ethylene oxide service every 5 years. We are also finalizing the proposed requirement for continuous monitoring of operating parameters for scrubbers used to control emissions from process vents in ethylene oxide service or storage tanks in ethylene oxide service, to ensure that the factors needed for the reaction to occur are met ( i.e., liquid-to-gas ratio, pressure drop across the scrubber, liquid feed pressure, liquid temperature, and pH), although we are revising the requirement to set the pressure drop across the scrubber and the liquid feed pressure based on the performance test, and instead, we are allowing the limits on these parameters to be based on the manufacturer's recommendations or engineering analysis. Additionally, we are changing the continuous compliance requirements for the operating parameters, such that compliance with the operating parameter limits is determined on an hourly average basis instead of an instantaneous basis. For equipment leaks, the EPA is promulgating final amendments for co-proposed equipment leak “Control Option 1” for controlling emissions from MON equipment in ethylene oxide service, except based on comments received on the proposed rulemaking, in lieu of prohibiting PRDs in ethylene oxide service from releasing directly to the atmosphere, we are clarifying in the final rule that these PRDs must comply with the pressure release management work practice standards proposed at 40 CFR 63.2480(e) and (f). We are also clarifying that any release event from PRDs in ethylene oxide service is a deviation of the standard. The EPA is not finalizing co-proposed equipment leak “Control Option 2.” As proposed under equipment leak Control Option 1, we are promulgating the following requirements: • All light liquid pumps in ethylene oxide service be monitored monthly at a leak definition of 1,000 ppm, and when a leak is detected, it be repaired as soon as practicable, but not later than 15 calendar days after it is detected; • the leak repair exemption available for pumps at 40 CFR 63.1026(b)(3), 40 CFR 63.163(c)(3), and 40 CFR 65.107(b)(3) does not apply to equipment in ethylene oxide service; and • all gas/vapor and light liquid connectors in ethylene oxide service are required to be monitored annually at a leak definition of 500 ppm, and when a leak is detected, be repaired as soon as practicable, but not later than 15 calendar days after it is detected. Refer to section IV.C.2 of the proposal preamble (84 FR 69182, December 17, 2019) for further discussion of co-proposed Control Option 1. Section IV.A.3 of this preamble provides a summary of key comments we received regarding the risk review and our responses. B. What are the final rule amendments based on the technology review for the Miscellaneous Organic Chemical Manufacturing source category? For process vents, storage tanks, transfer racks, and wastewater streams in this source category, the EPA is finalizing its proposed determination in the technology review that there are no developments in practices, processes, and control technologies that warrant revisions to the MACT standards. Therefore, we are not finalizing revisions to the MACT standards for these emission sources under CAA section 112(d)(6). For leaks from equipment not in ethylene oxide service, we determined that there are developments in practices, processes, and control technologies that warrant revisions to the MACT standards for this source category. Therefore, to satisfy the requirements of CAA section 112(d)(6), we are revising the MACT standards, consistent with the proposed rule (84 FR 69182, December 17, 2019), to lower the leak definition for pumps in light liquid service (in an MCPU that has no continuous process vents and is part of an existing source) from 10,000 ppmv to 1,000 ppmv with monthly monitoring to comply with the requirements in 40 CFR part 63, subpart H or UU, or 40 CFR part 65, subpart F, and to require initial monitoring for equipment leaks within 30 days after initial startup of new or replaced equipment. However, based on comments received on the proposed rulemaking, we are clarifying in the final rule that the initial monitoring of equipment is only required if the new or replaced equipment is subject to Table 6 to 40 CFR part 63, subpart FFFF, and is also subject to periodic monitoring with EPA Method 21 of appendix A-7 to 40 CFR part 60; and that the initial monitoring does not apply to equipment classified as unsafe-to-monitor or difficult-to-monitor equipment. For heat exchange systems, we determined that there are developments in practices, processes, and control technologies that warrant revisions to the MACT standards for this source category. Therefore, to satisfy the requirements of CAA section 112(d)(6), we are revising the MACT standards, consistent with the proposed rule (84 FR 69182, December 17, 2019), to include revisions to the heat exchange system requirements to require owners or operators to use the Modified El Paso Method and repair leaks of total strippable hydrocarbon concentration (as methane) in the stripping gas of 6.2 ppmv or greater. However, based on comments received on the proposed rulemaking, we are also making some technical clarifications to allow compliance with the Modified El Paso Method using an alternative mass-based leak action level of total strippable hydrocarbon equal to or greater than 0.18 kilograms per hour (instead of the proposed concentration-based leak action level) for small heat exchange systems with a recirculation rate of 10,000 gallons per minute (gpm) or less. We are also finalizing the proposed specification that none of the heat exchange system requirements apply to heat exchange systems that have a maximum cooling water flow rate of 10 gpm or less. Section IV.B.3 of this preamble provides a summary of key comments we received on the technology review and our responses. C. What are the final rule amendments pursuant to CAA section 112(d)(2) and (3) and 112(h) for the Miscellaneous Organic Chemical Manufacturing source category? Consistent with Sierra Club v. EPA 551 F. 3d 1019 (D.C. Cir. 2008) and the December 17, 2019, RTR proposal (84 FR 69182), we are revising monitoring and operational requirements for flares that control ethylene oxide emissions and flares used to control emissions from processes that produce olefins and polyolefins (with the option for an owner or operator of a flare outside of this subset to choose to opt in to the proposed requirements in lieu of complying with the current flare standards) to ensure these flares meet the MACT standards at all times when controlling HAP emissions. However, based on comments received on the proposed rulemaking, we are not finalizing the work practice standard for velocity exceedances for flares operating above their smokeless capacity. We are also clarifying in the final rule that a “flare that controls ethylene oxide emissions” is a flare that controls ethylene oxide emissions from affected sources in ethylene oxide service as defined in 40 CFR 63.2550. In addition, we are clarifying in the final rule that “an MCPU that produces olefins or polyolefins” includes only those MCPUs that manufacture ethylene, propylene, polyethylene, and/or polypropylene as a product; conversely, by-products and impurities as defined in 40 CFR 63.101, as well as wastes and trace contaminants, are not considered products. In addition, we are finalizing provisions and clarifications as proposed for periods of SSM and bypasses, including PRD releases; bypass lines on closed vent systems; maintenance activities; and certain gaseous streams routed to a fuel gas system to ensure that CAA section 112 standards apply continuously. Lastly, based on comments received on the proposed rulemaking, we are finalizing a separate standard for storage vessel degassing for storage vessels subject to the control requirements in Table 4 to 40 CFR part 63, subpart FFFF. Section IV.C.3 of this preamble provides a summary of key comments we received on the CAA section 112(d)(2) and (3) provisions and our responses. D. What are the final rule amendments addressing emissions during periods of SSM? We are finalizing the proposed amendments to the MON to remove and revise provisions related to SSM. In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008), the Court vacated portions of two provisions in the EPA's CAA section 112 regulations governing the emissions of HAP during periods of SSM. Specifically, the Court vacated the SSM exemptions contained in 40 CFR 63.6(f)(1) and (h)(1), holding that under section 302(k) of the CAA, emissions standards or limitations must be continuous in nature and that the SSM exemptions violate the CAA's requirement that some CAA section 112 standards apply at all times. As detailed in section IV.E.1 of the proposal preamble (see 84 FR 69182, December 17, 2019), the MON requires that the standards apply at all times (see 40 CFR 63.2450(a)(2)), consistent with the Court decision in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008). We determined that facilities in this source category can meet the applicable MACT standards at all times, including periods of startup and shutdown. As discussed in the proposal preamble, the EPA interprets CAA section 112 as not requiring emissions that occur during periods of malfunction to be factored into development of CAA section 112 standards, although the EPA has the discretion to set standards for malfunction periods where feasible. Where appropriate, and as discussed in section III.C of this preamble, we are also finalizing alternative standards for certain emission points during periods of SSM to ensure a CAA section 112 standard applies “at all times.” Other than for those specific emission points discussed in section III.C of this preamble, the EPA determined that no additional standards are needed to address emissions during periods of SSM. We determined that facilities in this source category can meet the applicable MACT standards at all times, including periods of startup and shutdown. We are finalizing revisions to the General Provisions table (Table 12 to 40 CFR part 63, subpart FFFF) to eliminate requirements that include rule language providing an exemption for periods of SSM. Additionally, we are finalizing our proposal to eliminate language related to SSM that treats periods of startup and shutdown the same as periods of malfunction. Finally, we are finalizing our proposal to revise reporting and recordkeeping requirements for deviations as they relate to exemptions for periods of SSM. As discussed in section IV.E.1 of the proposal preamble, these revisions are consistent with the requirement in 40 CFR 63.2450(a)(2) that the standards apply at all times. We are also finalizing, as proposed, a revision to the performance testing requirements. The final performance testing provisions prohibit performance testing during SSM because these conditions are not representative of normal operating conditions. The final rule also requires, as proposed, that operators maintain records to document that operating conditions during the test represent normal operations. The legal rationale and detailed revisions for SSM periods that we are finalizing here are set forth in the proposal preamble (84 FR 69224-69227, December 17, 2019). Also, based on comments received during the public comment period, we are revising specific references listed in 40 CFR 63.2450(e)(4), 40 CFR 63.2480(f), and 40 CFR 63.2485(p) and (q) to sufficiently address the SSM exemption provisions from subparts referenced by the MON ( e.g., the MON references 40 CFR part 63, subparts F, G, SS, UU, WW, and GGG; and each of these referenced subparts have SSM provisions that we are removing in 40 CFR 63.2450(e)(4), 40 CFR 63.2480(f), and 40 CFR 63.2485(p) and (q) for owners or operators that must comply with the MON). In other words, in addition to what we proposed, we are also clarifying that the certain referenced provisions do not apply when demonstrating compliance with the MACT standards, such as phrases like “other than a start-up, shutdown, or malfunction” in the recordkeeping and reporting requirements of 40 CFR part 63, subparts SS and UU. We are also not removing as proposed the term “breakdowns” in 40 CFR 63.998(b)(2)(i) as we determined based on a public comment that removing the term is unnecessary and could result in inaccurate calculation of parameter values. Finally, we are also not removing 40 CFR 63.998(d)(1)(ii) in its entirety as proposed because we determined based on a public comment received that these records are used to demonstrate compliance with the bypass provisions and do not apply to SSM. As discussed in section III.C of this preamble, we are also finalizing alternative standards for certain emission points ( i.e., emergency flaring, PRDs, maintenance activities, and tank degassing) during periods of SSM to ensure a CAA section 112 standard applies “at all times.” Section IV.D.3 of this preamble provides a summary of key comments we received on the SSM provisions and our responses. E. What other changes have been made to the NESHAP? This rule also finalizes, as proposed, revisions to several other NESHAP requirements. We describe these revisions in this section as well as other proposed provisions that have changed since proposal. 1. Electronic Reporting To increase the ease and efficiency of data submittal and data accessibility, we are finalizing, as proposed, a requirement that owners or operators of MON facilities submit electronic copies of certain required flare management plans (being finalized at 40 CFR 63.2450(e)(5)(iv)), compliance reports (being finalized at 40 CFR 63.2520(e)), performance test reports (being finalized at 40 CFR 63.2520(f)), and performance evaluation reports (being finalized at 40 CFR 63.2520(g)) through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI). The final rule requires that performance test results collected using test methods that are supported by the EPA's Electronic Reporting Tool (ERT) as listed on the ERT website 3 at the time of the test be submitted in the format generated through the use of the ERT and that other performance test results be submitted in portable document format (PDF) using the attachment module of the ERT. Similarly, performance evaluation results of continuous emissions monitoring systems (CEMS) measuring relative accuracy test audit pollutants that are supported by the ERT at the time of the test must be submitted in the format generated through the use of the ERT and other performance evaluation results be submitted in PDF using the attachment module of the ERT. For compliance reports, the final rule requires that owners or operators use the appropriate spreadsheet template to submit information to CEDRI. The final version of the template for these reports will be located on the CEDRI website. 4 The final rule requires that flare management plans be submitted as a PDF upload in CEDRI. In addition, in the final rule, we are correcting an error to clarify that compliance reports must be submitted electronically ( i.e., through the EPA's CDX using the appropriate electronic report template for this subpart) beginning August 12, 2023, or once the reporting template has been available on the CEDRI website for 1 year, whichever date is later. Furthermore, we are finalizing, as proposed, provisions that allow facility operators the ability to seek extensions for submitting electronic reports for circumstances beyond the control of the facility, i.e., for a possible outage in the CDX or CEDRI or for a force majeure event in the time just prior to a report's due date, as well as the process to assert such a claim. 3 https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert. 4 https://www.epa.gov/electronic-reporting-air-emissions/cedri. For a more detailed discussion of these final amendments to the MON, see section IV.E.2.b of the proposal preamble (84 FR 69227, December 17, 2019), as well as section VI.C below on compliance with the Paperwork Reduction Act. For a more thorough discussion of electronic reporting, see the memorandum, Electronic Reporting Requirements for New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP) Rules, which is available in the docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0169). 2. Monitoring for Adsorbers That Cannot Be Regenerated and Regenerative Adsorbers That Are Regenerated Offsite We are finalizing requirements at 40 CFR 63.2450(e)(7), as proposed, for owners or operators using adsorbers that cannot be regenerated and regenerative adsorbers that are regenerated offsite to use dual (two or more) adsorbent beds in series and conduct monitoring of HAP or total organic compound (TOC) on the outlet of the first adsorber bed in series using a sample port and a portable analyzer or chromatographic analysis. However, we are revising the proposed rule text in this final action to reduce the monitoring frequency in response to public comments. In the final rule, owners or operators will establish the estimated bed life from a design evaluation of the adsorber. The monitoring frequency increases as the remaining bed life decreases. Owners or operators will monitor monthly when remaining bed life is more than 2 months, weekly when remaining bed life is between 2 months and 2 weeks, and daily when remaining bed life is less than 2 weeks. 3. Exemptions for Heat Exchange Systems To correct a disconnect between having a National Pollutant Discharge Elimination System (NPDES) permit that meets certain allowable discharge limits at the discharge point of a facility ( e.g., outfall) and being able to adequately identify a leak, we are finalizing, as proposed, the removal of certain exemptions for once-through heat exchange systems to comply with cooling water monitoring requirements. 5 However, as discussed further in the response to comment document for this rulemaking, we are adding back in exemptions originating from 40 CFR 63.104(a)(1), (2), (5), and (6) that were inadvertently removed in the proposed rule. 5 Cooling water from a once-through heat exchange system at a petrochemical plant can be mixed with other sources of water ( e.g., cooling water used in once-through heat exchange systems in other source categories, stormwater, treated wastewater, etc.) in sewers, trenches, and ponds prior to discharge from the plant. If this point of discharge from the plant is into a “water of the United States,” then the facility is required to have a NPDES permit and to meet certain pollutant discharge limits. 4. Minor Clarifications and Corrections We are finalizing all of the revisions that we proposed for clarifying text or correcting typographical errors, grammatical errors, and cross-reference errors. These editorial corrections and clarifications are summarized in Table 11 of the proposal preamble. See 84 FR 69228, December 17, 2019. We are also including several additional minor clarifying edits in the final rule based on comments received during the public comment period. We did not receive many substantive comments on these other amendments in the Miscellaneous Organic Chemical Manufacturing RTR proposal. The comments and our specific responses to these items can be found in the document, Summary of Public Comments and Responses for the Risk and Technology Review for Miscellaneous Organic Chemical Manufacturing, available in the docket for this rulemaking. F. What are the effective and compliance dates of the standards? The revisions to the MACT standards being promulgated in this action are effective on August 12, 2020. New affected sources that commenced construction or reconstruction after December 17, 2019 must comply with all of the standards immediately upon the effective date of the standard, or upon startup, whichever is later. Existing sources and new affected sources that commenced construction or reconstruction after April 4, 2002, and on or before December 17, 2019, must comply with the amended standards according to the following compliance schedules, with two exceptions: (1) We are revising the General Provisions applicability table (Table 12 to 40 CFR part 63, subpart FFFF) to clarify that for all affected sources, the SSM exemptions contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1) do not apply given the Court vacatur in Sierra Club v. EPA, 551 F. 3d 1019 (D.C. Cir. 2008); and (2) electronic reporting of performance test reports and performance evaluations are required, as proposed, upon startup or no later than 60 days after the effective date of the final rule, whichever is later. • Upon initial startup or on August 12, 2023, whichever is later, for the following amendments: (1) The amendments specified in 40 CFR 63.2445(g), which include all amendments finalized under CAA sections 112(d)(2) and (3) and the heat exchange systems amendments finalized under CAA section 112(d)(6); (2) the amendments related to SSM at 40 CFR 63.2420(e)(4) and 63.2525(j); and (3) the amendments related to electronic reporting of flare management plans at 40 CFR 63.2450(e)(5)(iii) and compliance reports. • Upon initial startup or on August 12, 2021, whichever is later, for the amendments specified in 40 CFR 63.2445(h), which include the amendments finalized under CAA section 112(d)(6) for equipment leaks (i.e., pumps in light liquid service in an MCPU that has no continuous process vents and is part of an existing source). • Upon initial startup or on August 12, 2022, whichever is later, for the amendments specified in 40 CFR 63.2445(i), which include amendments finalized under CAA section 112(f) for process vents, storage tanks, and equipment that are in ethylene oxide service. Except for the compliance schedule for the SSM exemptions contained in 40 CFR 63.6(f)(1) and (h)(1) as previously described in this section of the preamble, these compliance schedules have not changed from proposal. However, we are correcting a typographical error to include the word “on” in the phrase “upon initial startup or on” of each schedule. We provide a summary in this section of our rationale for the compliance schedule being finalized for existing sources and new affected sources that commenced construction or reconstruction after April 4, 2002, and on or before December 17, 2019. Refer to section IV.F of the proposal preamble (84 FR 69182, December 17, 2019) for additional detail regarding our rationale for the compliance schedules being finalized, with the exception of the compliance schedule for the amendments finalized under CAA section 112(d)(6) for equipment leaks, which is discussed below. We received comments both in support of and in opposition to the proposed compliance schedules. Most commenters generally supported the proposed compliance schedules and said that owners or operators would need a significant period of time to comply with the proposed revisions. Only one commenter objected to the proposed compliance schedules, and primarily argued against the proposed 2-year compliance delay for the amendments made under CAA section 112(f) (for process vents, storage tanks, and equipment that are in ethylene oxide service). Summaries of these comments and the EPA's responses can be found in the document, Summary of Public Comments and Responses for the Risk and Technology Review for Miscellaneous Organic Chemical Manufacturing, available in the docket for this rulemaking. CAA section 112(i) provides that the compliance date shall be as expeditious as practicable, but no later than 3 years after the effective date of the standard. In determining what compliance period is as expeditious as practicable, we consider the amount of time needed to plan and construct projects and change operating procedures. For all amendments being finalized under CAA sections 112(d)(2) and (3), the heat exchange systems amendments being finalized under CAA section 112(d)(6), the amendments related to SSM (except for the SSM exemptions contained in 40 CFR 63.6(f)(1) and (h)(1) as previously described in this section of the preamble), and electronic reporting of flare management plans and compliance reports, we determined that sources will require up to 3 years after August 12, 2020 to comply with the requirements for the following reasons: • The operating and monitoring requirements for flares being finalized under CAA sections 112(d)(2) and (3) will require the installation of new flare monitoring equipment and likely a new control system to monitor and adjust assist gas addition rates, which will require the flare to be taken out of service and may require a significant portion of the MCPU to be shutdown. • The work practice standards for atmospheric PRDs in organic HAP service being finalized under CAA sections 112(d)(2) and (3) will necessitate sources to identify the most appropriate preventive measures or control approach; design, install, and test the system; install necessary process instrumentation and safety systems; and may need to time installations with equipment shutdown or maintenance outages. • The vent control requirements for bypasses being finalized under CAA sections 112(d)(2) and (3) will require the addition of piping and potentially new controls, which will likely be routed to the flare, such that these bypass modifications will need to be coordinated with the installation of the new monitoring equipment for the flares. • The heat exchange system amendments being finalized under CAA section 112(d)(6) will require engineering evaluations, solicitation and review of vendor quotes, contracting and installation of monitoring equipment, operator training, and updating standard operating procedures. • The removal of the exemptions from the requirements to meet the standard during SSM periods and the addition of electronic reporting will necessitate reading and understanding these new requirements, evaluation of operations to ensure that they can meet the standards during periods of startup and shutdown, making necessary adjustments to standard operating procedures, and converting reporting mechanisms to install necessary hardware and software. In sum, considering the timeframe needed to come into compliance with all of the removed exemptions in this final rule (which in certain cases, will require installation of complex equipment and system changes for flares), the EPA considers a period of 3 years after the effective date of the final rule to be the most expeditious compliance period practicable. For the equipment leak amendments being finalized under CAA section 112(d)(6), for pumps in light liquid service (in an MCPU that has no continuous process vents and is part of an existing source), we determined that sources will require up to 1 year after August 12, 2020 because, while the change to lower the leak definition can be implemented relatively quickly as it requires no additional equipment, it will still require changes to a facilities monitoring program and coordination in monitoring schedules, changes to recordkeeping activities and electronic databases, and changes to reporting forms. For all amendments being finalized under CAA section 112(f) for process vents in ethylene oxide service, storage tanks in ethylene oxide service, and equipment in ethylene oxide service, we determined that sources will require up to 2 years after August 12, 2020 to comply with the requirements to allow time to plan, purchase, and install equipment for ethylene oxide control. For example, for process vents, if the affected source cannot demonstrate 99.9-percent control of ethylene oxide emissions or reduce ethylene oxide emissions to less than 1 ppmv (from each process vent) or 5 lb/yr (for all combined process vents), then a new control system will need to be installed. Sufficient time will be needed to properly engineer the project, obtain capital authorization and funding, procure the equipment, construct and start-up the equipment, prepare for the initial performance test, set up new software, and develop operating procedures. IV. What is the rationale for our final decisions and amendments for the Miscellaneous Organic Chemical Manufacturing source category? For each issue, this section provides a description of what we proposed and what we are finalizing for the issue, the EPA's rationale for the final decisions and amendments, and a summary of key comments and responses. For all comments not discussed in this preamble, comment summaries and the EPA's responses can be found in the comment summary and response document available in the docket for this rulemaking. A. Residual Risk Review for the Miscellaneous Organic Chemical Manufacturing Source Category 1. What did we propose pursuant to CAA section 112(f) for the Miscellaneous Organic Chemical Manufacturing source category? Pursuant to CAA section 112(f), the EPA conducted a residual risk review and presented the results of this review, along with our proposed decisions regarding risk acceptability and ample margin of safety, in the December 17, 2019, proposed rule for 40 CFR part 63, subpart FFFF (84 FR 69182). The results of the risk assessment for the proposal are presented briefly in Table 2 of this preamble. More detail is in the residual risk technical support document, Residual Risk Assessment for the Miscellaneous Organic Chemical Manufacturing Source Category in Support of the 2019 Risk and Technology Review Proposed Rule, which is available in the docket for this rulemaking (see Docket Item No. EPA-HQ-OAR-2018-0746-0011). Table 2—Miscellaneous Organic Chemical Manufacturing Source Category Risk Assessment Results in Proposal Number of facilities 1 Maximum individual cancer risk (in 1 million) 2 Estimated population at increased risk of cancer 2 >100-in-1 million ≥1-in-1 million Estimated annual cancer incidence (cases per year) 2 Maximum chronic noncancer TOSHI 2 Maximum screening acute noncancer HQ 194 2,000 18,000 2,900,000 0.4 1 HQ REL = 6 (acrolein). 1 Number of facilities evaluated in the risk analysis. 2 Maximum individual excess lifetime cancer risk due to HAP emissions from the source category. 3 Actual emissions equal allowable emissions; therefore, actual risks equal allowable risks. The results of the proposed chronic baseline inhalation cancer risk assessment at proposal indicated that, based on estimates of current actual and allowable emissions, the MIR posed by the source category was 2,000-in-1 million driven by ethylene oxide emissions from storage tanks (75 percent), equipment leaks (15 percent), and process vents (8 percent). At proposal, the total estimated cancer incidence from this source category was estimated to be 0.4 excess cancer cases per year, or one case in every 2.5 years. Approximately 2.9 million people were estimated to have cancer risks above 1-in-1 million from HAP emitted from the facilities in this source category. At proposal, the estimated maximum chronic noncancer target organ-specific hazard index (TOSHI) for the source category was 1, indicating low likelihood of adverse noncancer effects from long-term inhalation exposures. As shown in Table 2 of this preamble, the worst-case acute hazard quotient (HQ) (based on the reference exposure level (REL)) at proposal was 6 based on the REL for acrolein (the next highest dose-response value for acrolein, the acute exposure guideline level-1 (AEGL-1), results in an HQ of 0.2). There were 11 additional instances of acute HQs greater than 1 from the source category. In addition, at proposal, the multipathway risk screening assessment resulted in a maximum Tier 2 cancer screening value (SV) of 10 for polycyclic organic matter (POM) for the farmer scenario. The Tier 2 SVs for all other HAP known to be persistent and bio-accumulative in the environment (PB-HAP) emitted from the source category (mercury compounds, cadmium compounds, and arsenic compounds) were less than 1. The Tier 2 cancer SV for POM means that the maximum cancer risk from exposure to POM emissions through ingestion of farm products is less than 10-in-1 million. At proposal, no site-specific assessment using TRIM.FaTE (which incorporates AERMOD deposition, enhanced soil/water run-off calculations, and model boundary identification) or Tier 3 screening assessment was deemed necessary due to the conservative nature of the Tier 2 screen and the hypothetical construct of the farmer scenario. Also, at proposal, the highest annual average lead concentration of 0.0006 micrograms per cubic meter was well below the National Ambient Air Quality Standards for lead, indicating low potential for multipathway risk of concern due to lead emissions. At proposal, the maximum lifetime individual cancer risk posed by the 194 modeled facilities, based on whole facility emissions, was 3,000-in-1 million, with ethylene oxide emissions from fugitive emissions and flares from the Synthetic Organic Chemical Manufacturing, Polyether Polyols Production, and Miscellaneous Organic Chemical Manufacturing source categories driving the risk. Regarding the noncancer risk assessment, the maximum chronic noncancer hazard index (HI) posed by whole facility emissions was estimated to be 7 (for the respiratory system as the target organ), driven by emissions of chlorine and methyl bromide from non-source category sources identified as brominated organic manufacturing. We weighed all health risk factors, including those shown in Table 2 of this preamble, in our risk acceptability determination and proposed that the risks posed by this source category under the current MACT provisions are unacceptable (section IV.C of the proposal preamble, 84 FR 69182, December 17, 2019). At proposal, we identified ethylene oxide as the driver of the unacceptable risk and evaluated several options to control ethylene oxide emissions from (1) process vents, (2) storage tanks, and (3) equipment “in ethylene oxide service.” For process vents, we proposed to define “in ethylene oxide service” to mean that each batch and continuous process vent in a process that, when uncontrolled, contains a concentration of greater than or equal to 1 ppmv undiluted ethylene oxide, and when combined, the sum of all these process vents would emit uncontrolled, undiluted ethylene oxide emissions greater than or equal to 5 lb/yr (2.27 kg/yr). For storage tanks of any capacity and vapor pressure, we proposed to define “in ethylene oxide service” to mean that the concentration of ethylene oxide of the stored liquid is greater than or equal to 1 ppmw. We proposed that the exemptions for “vessels storing organic liquids that contain HAP only as impurities” and “pressure vessels designed to operate in excess of 204.9 kilopascals and without emissions to the atmosphere” listed in the definition of “storage tank” at 40 CFR 63.2550(i) do not apply for storage tanks in ethylene oxide service. For the ethylene oxide equipment leak provisions, we proposed to define “in ethylene oxide service” to mean any equipment that contains or contacts a fluid (liquid or gas) that is at least 0.1 percent by weight of ethylene oxide. To reduce risks from process vents in ethylene oxide service, we proposed requirements at 40 CFR 63.2493 to reduce emissions of ethylene oxide by either (1) venting emissions through a closed-vent system to a control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight, to a concentration less than 1 ppmv for each process vent, or to less than 5 lb/yr for all combined process vents; or (2) venting emissions through a closed-vent system to a flare meeting the flare operating requirements discussed in section IV.A.1 of the proposal preamble (84 FR 69182, December 17, 2019). To reduce risks from storage tanks in ethylene oxide service, we proposed a requirement at 40 CFR 63.2493 to reduce emissions of ethylene oxide by either (1) venting emissions through a closed-vent system to a control device that reduces ethylene oxide by greater than or equal to 99.9 percent by weight or to a concentration less than 1 ppmv for each storage tank vent; or (2) venting emissions through a closed-vent system to a flare meeting the flare operating requirements discussed in section IV.A.1 of the proposal preamble (84 FR 69182, December 17, 2019). To reduce risks from equipment leaks in ethylene oxide service, we co-proposed two control options at 40 CFR 63.2493 (see Table 6 of the proposal preamble, 84 FR 69182, December 17, 2019). In equipment leak co-proposed Control Option 1, we proposed that all light liquid pumps in ethylene oxide service be monitored monthly at a leak definition of 1,000 ppm, and when a leak is detected, it be repaired as soon as practicable, but not later than 15 calendar days after it is detected. Additionally, under co-proposed Control Option 1, we proposed that the leak repair exemption available for pumps at 40 CFR 63.1026(b)(3), 40 CFR 63.163(c)(3), and 40 CFR 65.107(b)(3) would not apply to equipment in ethylene oxide service. Also, as part of co-proposed Control Option 1, we proposed that all gas/vapor and light liquid connectors in ethylene oxide service be monitored annually at a leak definition of 500 ppm, and when a leak is detected, it be repaired as soon as practicable, but not later than 15 calendar days after it is detected. In equipment leak co-proposed Control Option 2, we proposed that more stringent equipment leak standards would apply to two facilities with a MIR greater than 100-in-1 million ( i.e., Lanxess Corporation and Huntsman Performance). For these two facilities, at proposal, light liquid pumps in ethylene oxide service would be required to be leakless ( i.e., have zero emissions) and monitored annually to verify there are no emissions; and gas and light liquid valves in ethylene oxide service would be required to either be leakless and monitored annually or not be leakless and be monitored quarterly. For these two facilities, at proposal, light liquid pumps and gas and light liquid valves in ethylene oxide service would be considered leaking if an instrument reading above background is found; and connectors in ethylene oxide service would be monitored monthly at a leak definition of 100 ppm. We proposed that when a leak is detected, it be repaired as soon as practicable, but not later than 15 calendar days after it is detected, and a first attempt at repair be made no later than 5 calendar days after the leak is detected. As part of co-proposed Control Option 2, we proposed all other facilities with MON equipment in ethylene oxide service would be subject to the standards previously described in equipment leak co-proposed Control Option 1. After implementation of the proposed controls for process vents and storage tanks at MON facilities emitting ethylene oxide, as well as implementation of either of the co-proposed control options for equipment leaks, we proposed that the resulting risks would be acceptable for this source category. We also acknowledged at proposal that estimated post-control risks would be greater than 100-in-1 million ( i.e., 200- to 300-in-1 million) and determined that, due to the inherent health protective nature of our risk assessment methods and certain uncertainties, 6 the proposed risk assessment is more likely to overestimate rather than underestimate the risks (see section IV.C.3 of the proposal preamble, 84 FR 69182, December 17, 2019). In our proposal, we presented the risk impacts using health risk measures and information, including the MIR, cancer incidence, population exposed to cancer risks greater than 100-in-1 million, and associated uncertainty in emissions estimates after incremental application of the proposed options to control ethylene oxide emissions from (1) process vents, (2) storage tanks, and (3) equipment in ethylene oxide service (see Table 7 of the proposal preamble, 84 FR 69182, December 17, 2019). At proposal, we determined application of the ethylene oxide-specific controls for process vents and storage tanks would reduce ethylene oxide emissions by an estimated 89 percent for the source category, and the estimated MIR would be reduced from 2,000-in-1 million to 400-in-1 million at Lanxess Corporation, and the next highest estimated MIR would be 300-in-1 million at Huntsman Performance. In both cases, we determined that the remaining risk would be primarily from equipment leak emissions of ethylene oxide. Subsequent application of equipment leak co-proposed Control Option 1 would further reduce ethylene oxide emissions by 4 percent, for a total estimated 93-percent reduction in ethylene oxide emissions for the source category, with the MIR at Lanxess Corporation being further reduced to 200-in-1 million and the MIR at Huntsman Performance remaining at 300-in-1 million. Alternatively, subsequent application of equipment leak co-proposed Control Option 2 (instead of Control Option 1) would reduce ethylene oxide emissions by a total estimated 94-percent for the source category, with the MIR at Lanxess Corporation being further reduced to 100-in-1 million and the MIR at Huntsman Performance being reduced to 200-in-1 million. 6 Uncertainties regarding the equipment leak emissions, the uncertainties inherent in all risk assessments ( i.e., the emissions dataset, dispersion modeling, exposure estimates, and dose-response relationships), and the EPA's use of the 2016 unit risk estimate (URE) for ethylene oxide (which is developed to be health protective). At proposal, we requested comments on the use of the 2016 updated URE 7 for ethylene oxide for regulatory purposes beyond those already received for the Hydrochloric Acid (HCl) Production RTR proposed rule (84 FR 1584-1597, February 4, 2019), as well as comments on the use of an alternative URE for ethylene oxide in the final rule for this source category. We also solicited comment on which of the two ethylene oxide equipment leak co-proposed control options should be implemented in the final rulemaking in order to ensure that risks from the source category are acceptable. 7 The URE is an upper-bound estimate of an individual's incremental risk of contracting cancer over a lifetime of exposure to a concentration of 1 microgram of the pollutant per cubic meter of air. For residual risk assessments, we generally use UREs from the EPA's Integrated Risk Information System (IRIS). For carcinogenic pollutants without IRIS values, we look to other reputable sources of cancer dose-response values, where available. In cases where new, scientifically credible dose-response values have been developed in a manner consistent with EPA guidelines and have undergone a peer review process similar to that used by the EPA, we may use such dose-response values in place of, or in addition to, other values, if appropriate. The pollutant-specific dose-response values used to estimate cancer health risk are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants. We then considered whether the existing MACT standards provide an ample margin of safety to protect public health and whether, taking into consideration costs, energy, safety, and other relevant factors, and whether additional standards are required to prevent an adverse environmental effect. To determine whether the rule provides an ample margin of safety, we considered the requirements that we proposed to achieve acceptable risks. We also considered implementing equipment leak co-proposed Control Option 2, which would require that the two facilities with estimated cancer risks greater than 100-in-1 million comply with more stringent standards. In addition, we considered expanding the applicability of equipment leak co-proposed Control Option 2 so that the more stringent controls would apply to all facilities with equipment in ethylene oxide service, regardless of estimated cancer risks. Finally, we considered the options identified in the technology review ( i.e., controls for equipment leaks for MON equipment not in ethylene oxide service and heat exchange systems). In considering whether the standards should be tightened to provide an ample margin of safety to protect public health, we considered the same risk factors that we considered for our acceptability determination and also examined the costs, technological feasibility, and other relevant factors related to emissions control options that might reduce risk associated with emissions from the source category. Based on these considerations, we proposed that the requirements that we proposed to achieve acceptable risks would also provide an ample margin of safety to protect public health (section IV.C.4 of the proposal preamble, 84 FR 69182, December 17, 2019). We also solicited comment on which of the available control options should be applied in order to provide an ample margin of safety to protect public health. 2. How did the risk review change for the Miscellaneous Organic Chemical Manufacturing source category? a. Miscellaneous Organic Chemical Manufacturing Source Category Risk Assessment As part of the final risk assessment, the EPA reanalyzed risks using emissions inventory updates that were received from a CAA section 114 request issued to the highest risk facility, and additional information received from the two highest risk facilities during the public comment period. These updates were primarily reductions to emissions of ethylene oxide and included revised actual emissions for two facilities and allowable emissions for one facility. The revised emissions used to reanalyze risks are available in the docket for this rulemaking (see section IV.A.3.b of this preamble and Appendix 1 of the Residual Risk Assessment for the Miscellaneous Organic Chemical Manufacturing Source Category in Support of the 2020 Risk and Technology Review Final Rule, available in the docket for this rulemaking, for more detail about these revised emissions). Based on the revised actual emission estimates, the results of the chronic inhalation cancer risk from the revised risk assessment indicate that the maximum lifetime individual cancer risk posed by the 194 facilities could be as high as 400-in-1 million, with ethylene oxide from process vents and equipment leaks as the major contributors to the risk. Specifically, the revised baseline cancer risk is reduced to 400-in-1 million for the Lanxess facility, and to less than 100-in-1 million for Huntsman Performance. The total estimated cancer incidence from the revised risk assessment is 0.1 excess cancer cases per year, or one excess case in every 10 years. Of the approximately 89,000,000 people that live within 50 kilometers (km) of the 194 facilities, 1,700,000 people were estimated to have cancer risks greater than or equal to 1-in-1 million from HAP emitted from the facilities in this source category. Approximately 46,000 people were estimated to have cancer risks greater than or equal to 10-in-1 million, and 1,200 people were estimated to have cancer risks greater than or equal to 100-in-1 million. Of those 1,200 people, approximately 860 are estimated to have cancer risks greater than 100-in-1 million (Table 3 of this preamble). The estimated maximum chronic noncancer TOSHI for the source category remained unchanged from the proposal at 1, indicating low likelihood of adverse noncancer effects from long-term inhalation exposures. Additionally, the worst-case acute HQ (based on the REL) remained unchanged from proposal (6 based on the REL for acrolein and the next highest dose-response value for acrolein, the AEGL-1, results in an HQ of 0.2). Similarly, the multipathway risk screening assessment remained unchanged from proposal and resulted in a maximum Tier 2 cancer SV of 10 for POM for the farmer scenario. The Tier 2 SVs for all other PB-HAP emitted from the source category (mercury compounds, cadmium compounds, and arsenic compounds) were less than 1. Whole facility risks also did not change from those at proposal based on revised emission estimates. The maximum lifetime individual cancer risk based on whole facility emissions was 3,000-in-1 million driven by ethylene oxide emissions from fugitive emissions and flares from the Synthetic Organic Chemical Manufacturing, Polyether Polyols Production, and Miscellaneous Organic Chemical Manufacturing source categories. The maximum chronic noncancer HI posed by whole facility emissions was estimated to be 7 (for the respiratory system as the target organ), driven by emissions of chlorine and methyl bromide from non-source category sources identified as brominated organic manufacturing. Based on revised allowable emission estimates, the maximum lifetime individual cancer risk could be as high as 800-in-1 million, with ethylene oxide from storage tanks, process vents, and equipment leaks driving the risk. The total estimated cancer incidence is 0.2 excess cancer cases per year, or 1 excess case in every 5 years. Approximately 2,000,000 people were estimated to have cancer risks greater than or equal to 1-in-1 million from allowable emissions, approximately 170,000 were estimated to have cancer risks greater than or equal to 10-in-1 million, and 4,200 people were estimated to have cancer risks greater than or equal to 100-in-1 million. Of those 4,200 people, approximately 1,700 are estimated to have cancer risks greater than 100-in-1 million (Table 3 of this preamble). Table 3—Miscellaneous Organic Chemical Manufacturing Source Category Risk Assessment Results Based on Revised Emissions in Final Rule Number of facilities 1 Maximum individual cancer risk (in 1 million) 2 Estimated population at increased risk of cancer 2 >100-in-1 million ≥1-in-1 million Estimated annual cancer incidence (cases per year) 2 Maximum chronic noncancer TOSHI 2 Maximum screening acute noncancer HQ Actual Emissions 194 400 860 1,700,000 0.1 1 HQ REL = 6 (acrolein). Allowable Emissions 194 800 1,700 2,000,000 0.2 1 1 Number of facilities evaluated in the risk analysis. 2 Maximum individual excess lifetime cancer risk due to HAP emissions from the source category. 3 Actual emissions equal allowable emissions with the exception of one facility, where additional information was available. Finally, risks were estimated after application of the controls finalized in this rulemaking for storage tanks, process vents, and equipment in ethylene oxide service, in addition to controls that apply to all HAP and were identified during the technology review (controls for heat exchangers and equipment leaks for MON equipment not in ethylene oxide service). Based on these controls, we estimated that the baseline cancer MIR of 400-in-1 million would be reduced to 200-in-1 million for actual emissions, with ethylene oxide from equipment leaks driving the risk. There would be 107 people estimated to have a cancer risk greater than 100-in-1 million, down from 860 people in the baseline scenario. There is an estimated reduction in cancer incidence to 0.09 excess cancer cases per year (or one excess case every 11 years), down from 0.1 excess cancer cases per year (or one excess cancer case every 10 years) in the baseline scenario. In addition, the number of people estimated to have a cancer risk greater than or equal to 1-in-1 million would be reduced from 1,700,000 to 1,400,000 (Table 4 of this preamble). For allowable emissions, we estimated that the baseline cancer MIR of 800-in-1 million would be reduced to 200-in-1 million, with ethylene oxide from equipment leaks driving the risk. There would be 115 people estimated to have a cancer risk greater than 100-in-1 million, down from 1,700 people in the baseline scenario. There is an estimated reduction in cancer incidence to 0.09 excess cancer cases per year (or one excess case every 11 years), down from 0.2 excess cancer cases per year (or one excess cancer case every 5 years) in the baseline scenario. In addition, the number of people estimated to have a cancer risk greater than or equal to 1-in-1 million would be reduced from 2,000,000 to 1,400,000 (Table 4 of this preamble). Table 4—Baseline and Post-Control Risk Summary for the Miscellaneous Organic Chemical Manufacturing Source Category Based on Revised Emissions in Final Rule Inhalation cancer risk Maximum individual risk (in 1 million) Risk driver Population cancer risk Cancer incidence (cases per year) >100-in-1 million ≥1-in-1 million Actual Emissions Baseline Risk 400 ethylene oxide 0.1 860 1,700,000 Post-control Risk 200 ethylene oxide 0.09 107 1,400,000 Allowable emissions Baseline Risk 800 ethylene oxide 0.2 1,700 2,000,000 Post-control Risk 200 ethylene oxide 0.09 115 1,400,000 We continue to find that the revised risks prior to control are unacceptable, and we are revising the final NESHAP for the Miscellaneous Organic Chemical Manufacturing source category pursuant to CAA section 112(f)(2) on the basis that risks are unacceptable. However, as discussed in sections IV.A.3 and IV.A.4 of this preamble, we find that, after implementation of the controls finalized in this rulemaking, the resulting risks would be acceptable for this source category and achieve an ample margin of safety. Additional details of the reanalyzed risks can be found in the Residual Risk Assessment for the Miscellaneous Organic Chemical Manufacturing Source Category in Support of the 2020 Risk and Technology Review Final Rule, available in the docket for this rulemaking. b. Rule Changes Based on comments received on the proposed rulemaking, we are revising the proposed definition of “in ethylene oxide service” for process vents by removing “undiluted” from mass-based criteria and removing the phrase “anywhere in the process.” In the final rule, a process vent in ethylene oxide service means each batch and continuous process vent in a process that, when uncontrolled, contains a concentration of greater than or equal to 1 ppmv undiluted ethylene oxide, and when combined, the sum of all these process vents would emit uncontrolled, ethylene oxide emissions greater than or equal to 5 lb/yr (2.27 kg/yr). In addition, based on comments received on the proposed rulemaking, we are revising the definitions of “batch process vent” and “continuous process vent” in the final rule to clarify that (1) the existing 50 ppmv HAP and 200 lb/yr uncontrolled HAP emission cut-offs do not apply to batch process vents in ethylene oxide service; and (2) the existing 0.005 weight percent total organic HAP cut-off in 40 CFR 63.107(d) does not apply to continuous process vents in ethylene oxide service. Based on comments received on the proposed rulemaking, we are also revising the proposed definition of “in ethylene oxide service” for storage tanks by revising the concentration of ethylene oxide criteria to a 0.1 percent by weight threshold. In the final rule, a storage tank in ethylene oxide service means a storage tank of any capacity and vapor pressure storing a liquid that is at least 0.1 percent by weight of ethylene oxide. For equipment leaks in ethylene oxide service, we are finalizing the co-proposed equipment leak “Control Option 1.” We are not promulgating final amendments for co-proposed equipment leak “Control Option 2.” Finally, based on comments received on the proposed rulemaking, we are also revising some of the continuous monitoring requirements for operating parameters for scrubbers used to control emissions from process vents in ethylene oxide service or storage tanks in ethylene oxide service. In the final rule, we are allowing the limits for the pressure drop across the scrubber and the liquid feed pressure to the scrubber to be based on the manufacturer's recommendations or engineering analysis instead of on the performance test. Additionally, we are changing the continuous compliance requirements for the operating parameters, such that compliance with the operating parameter limits is determined on an hourly average basis instead of an instantaneous basis. 3. What key comments did we receive on the risk review, and what are our responses? This section provides comment summaries and responses for the key comments received regarding the ethylene oxide IRIS URE, including those received for the HCl Production RTR proposed rule (84 FR 1584-1597, February 4, 2019), and our risk assessment for the Miscellaneous Organic Chemical Manufacturing source category, our proposed definition of “in ethylene oxide service,” proposed requirements for storage tanks and process vents in ethylene oxide service, and proposed requirements for equipment leaks in ethylene oxide service. We received comments in support of and against the proposed residual risk review, the IRIS URE used in the review, the American Chemistry Council's (ACC's) request for correction under the Information Quality Act asking that the “NATA risk estimates for E.O. 8 should be withdrawn and corrected to reflect scientifically supportable risk values,” and our determination that additional controls were warranted under CAA section 112(f)(2) for the Miscellaneous Organic Chemical Manufacturing source category. Other comments on these issues, as well as on additional issues regarding the residual risk review and the EPA's proposed changes based on the residual risk review, can be found in the document, Summary of Public Comments and Responses for the Risk and Technology Review for Miscellaneous Organic Chemical Manufacturing, available in the docket for this rulemaking. 8 In this instance, “E.O.” refers to “ethylene oxide.” a. Ethylene Oxide IRIS URE In the MON RTR proposed rule (84 FR 69182, December 17, 2019), as well as the HCl Production RTR proposed rule (84 FR 1584, February 4, 2019), we requested comment on the use of the updated ethylene oxide URE for regulatory purposes. Also, in the proposed rulemaking for the Miscellaneous Organic Chemical Manufacturing source category, we noted the ACC's request for correction under the Information Quality Act asking that the “NATA risk estimates for E.O. should be withdrawn and corrected to reflect scientifically supportable risk values.” Several commenters provided comments on these two topic areas as summarized below: Comment: We received extensive comments on use of the EPA ethylene oxide URE. Some commenters were in support of the continued use of the EPA URE and other commenters recommended changes to aspects of the EPA URE or recommended use of an alternative to the EPA URE. Many of the commenters recommending changes to the EPA URE focused on aspects of dose-response modeling that could affect the value of the EPA URE, including model selection, inclusion of breast cancer data, cohort selection, and historical exposure estimates. Other comments evaluated the biological plausibility of the EPA URE, including considerations of endogenous and ambient background ethylene oxide levels and mortality predictions. In some cases, commenters submitted analyses of existing data, including recent publications ( e.g., Marsh et al. 2019; Bogen et al. 2019; Kirman and Hays 2017). In addition, the Texas Commission on Environmental Quality (TCEQ) submitted their draft cancer dose-response assessment for ethylene oxide to the EPA for consideration as an alternative to the EPA URE for ethylene oxide. Response: A number of comments received on aspects of dose-response modeling largely touch on matters that were identified and discussed as part of the peer and public review processes for the EPA IRIS ethylene oxide Assessment, and the Agency considered those comments in the development of the final IRIS ethylene oxide Assessment. 9 The prior comments and responses are documented in the Appendices of the EPA 2016 IRIS ethylene oxide assessment 10 and are therefore addressed here by referencing the existing IRIS responses. For some of these topics, additional comments were submitted that either augment previous comments or address specific details of the final IRIS dose-response model that were not addressed during the peer-review process. For example, additional comments were submitted on pre-1978 exposure estimates and statistical evaluation of the dose-response model selected for lymphoid cancer. Additional detailed responses to these topics are provided in the response to comment document for this rulemaking. 9 Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (EtO), EPA/635/R-16/350fa. Available at https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=329730. 10 Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (EtO) Appendices, EPA/635/R-16/350fb. Available at https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=329730. Several public comments referred to recent analyses of existing data, including publications that focus on different aspects of ethylene oxide assessment such as weight of evidence for breast cancer (Marsh et al. 2019), estimates of ethylene oxide levels produced in our bodies (Kirman and Hays 2017), and evaluation of historical occupational exposure estimates (Bogen et al. 2019). As we detail in the response to comment document, consideration of these individual analyses did not prompt the Agency to pursue reassessment of the EPA's IRIS ethylene oxide Assessment for purposes of this rulemaking. For example, Marsh et al. analyzed breast cancer mortality and focused on comparing cancers seen in occupational groups with national or regional average rates; whereas, the EPA has generally focused on studies of breast cancer incidence since many women survive breast cancer. 11 With regard to the amount of ethylene oxide produced within the human body, Kirman and Hays did not include any direct measurements of endogenous ethylene oxide levels; however, they did measure a particular by-product (an adduct—chemical reaction product—with the protein hemoglobin) that could be associated with total ambient exposure (including both endogenous and ambient background) among non-occupationally exposed individuals. While studies of the hemoglobin adduct found it to be a useful marker for high level occupational exposures to ethylene oxide, there are many uncertainties in attempting to use this product as a direct measure of ambient background or endogenous levels of ethylene oxide in the body. Further, because the IRIS URE for ethylene oxide represents the increased cancer risk due to exposure to ethylene oxide emissions above endogenous ethylene oxide and ambient background levels, consideration of the findings of Kirman and Hays or other studies of endogenous or ambient background exposures would not impact the URE. The findings of Bogen et al. are discussed further in the response to comment document for this rulemaking. 11 Guidelines for Carcinogen Risk Assessment, EPA/630/P-03/001F, 2005. Available at: https://www.epa.gov/sites/production/files/2013-09/documents/cancer_guidelines_final_3-25-05.pdf. Though the TCEQ submitted their draft cancer dose-response assessment for ethylene oxide to the EPA as part of the public comment process, the assessment had not yet undergone peer review, and the TCEQ dose-response value had not yet been finalized by the close of the public comment period for this rulemaking, which closed on March 19, 2020. 12 Therefore, the TCEQ dose-response value could not be considered for this rulemaking. 12 Note that the final TCEQ assessment was issued on May 15, 2020. For these reasons, we have decided to continue to use the EPA URE for ethylene oxide for the risk analyses performed for this final rulemaking. As always, the EPA remains open to new and updated scientific information, as well as new dose response values such as the TCEQ value, as they become available. Comment: Several commenters supported the ACC's request for correction. Other commenters indicated that there was no justification for a correction to the EPA URE for ethylene oxide. Response: In a letter to the ACC dated December 18, 2019, the then-acting Assistant Administrator for Air and Radiation stated that “[b]ecause EPA received comments from the ACC and others on the HCl proposed rule related to use of information in the 2016 EtO IRIS Assessment,” and “given that EPA anticipates receiving additional comments focused on the 2016 EtO IRIS Assessment in the MON RTR rulemaking,” the EPA believed at that time that it was “appropriate to address this [request for correction] as part of the MON RTR rulemaking.” 13 Having now reviewed and considered the comments it has received, the EPA has determined that it is appropriate to defer providing a final response to the ACC's request at this time. The EPA is under a court ordered deadline requiring signature of the final MON RTR by May 29, 2020, and we have determined that, given the time available and in light of other resource constraints, completing our consideration of the Information Quality Act request for correction in conjunction with taking final action in this rulemaking is not practicable. Accordingly, in order to ensure that the ACC's request for correction is given the complete attention it warrants, we have determined that it is appropriate to issue this final CAA rule separately from the Agency response to the ACC request. We anticipate taking final action on the Information Quality Act request for correction in the near future. 13 See Letter from Anne L. Idsal, acting Assistant Administrator for Air and Radiation to William P. Gulledge, American Chemistry Council (December 18, 2019). Similarly, in the proposed rulemaking, we took note of the fact that, “[g]iven the ACC's Response for Correction,” we had in the earlier HCl Production RTR proposed rule “requested comment on the use of the updated ethylene oxide URE for regulatory purposes.” 84 FR 69218 (December 17, 2019). “Because of the robustness of the comment received and their relevance to this rulemaking,” we said that the Agency would “consider those comments in the final rule for the Miscellaneous Organic Chemical Manufacturing source category.” Id. b. MON Risk Assessment Several commenters provided comments on specific facilities in the EPA risk assessment and submitted additional data for the EPA to use for assessing public health risks. Those comments are as follows: Comment: One commenter contended that the EPA conducted a CAA section 114 data collection effort on the highest risk facility, Lanxess, but did not use the data at proposal, even though the results of the performance testing were received in September 2019. The commenter disagreed with the EPA's decision that any changes received by September 2018 were incorporated into the RTR modeling file, and after September 2018 and before February 2019, only minor changes related to MON applicability of ethylene oxide emissions were incorporated into the RTR modeling file. Commenters stated that the EPA has significantly overestimated the risks posed by the Lanxess facility and that if the EPA used the most recent and best available data, the Lanxess facility would not be classified as a high-risk site. As justification, the commenters provided new stack test data for Lanxess' two process scrubbers and the storage tank scrubber based on performance tests conducted from June 3 to June 20, 2019. The commenters provided that the preliminary results from the performance tests indicate that the total ethylene oxide emissions from the three scrubbers were significantly less than the initial estimate that was used for the risk analysis and proposed rule. 14 Commenters observed that the risk analysis published at proposal did not include this most recent stack test data. 14 Commenter referred to Docket Item No. EPA-HQ-OAR-2018-0746-0022. One commenter also objected to the EPA using a different approach to establish baseline emissions for the Lanxess facility as compared with all other MON facilities and objected to the EPA proposing a more stringent control technology standard specifically for this facility based on incomplete data and a different standard from that which was applied to all other facilities. The commenter reiterated that for the Lanxess facility, the EPA disregarded actual 2014 emissions data for storage tanks and process vents and estimated emissions for fugitives using component counts and emission factors, which the EPA acknowledged likely resulted in emission estimates that were biased high. The commenter provided updated information and requested that the facility emissions, like the other MON facilities, be analyzed based on 2014 actual emissions. Some commenters requested that the EPA update the emission estimate for the site to reflect a control efficiency of 99.9 percent for the ethylene oxide storage tank scrubber and use 2014 actual emissions data, which would establish a 0.0107 tpy baseline for this scrubber. The commenters further asserted that the EPA chose not to use reported 2014 ethylene oxide emissions associated with the two scrubbers that control emissions from the two process vents in ethylene oxide service and instead calculated potential emission rates using the facility's 2012 title V application, which resulted in a modeling input of almost twice the actual emissions and was not consistent with the method the EPA utilized to review risk for the other MON facilities. The commenters requested that the EPA use the reported values contained in the calendar year 2014 emissions inventory for the two process vent scrubbers to establish the baseline for risk. Commenters further contested the EPA's approach to estimating fugitive emissions and emissions from equipment leaks; commenters did not agree with estimating fugitive emissions based on potential emissions in lieu of 2014 actual emissions. Further, the commenters requested that the EPA update the equipment leak source parameters to a volume source versus an area source to better represent equipment leak emissions, and to update the risk inputs to use current equipment counts, composition of ethylene oxide in the streams, the emission factors from Table 6 of the EPA's equipment leak evaluation memorandum, Analysis of Control Options for Equipment Leaks at Processes that use ethylene oxide Located in the Miscellaneous Organic Chemical Manufacturing Source Category, and the facility's actual hours of operation in 2014. The commenters also stated that the facility has no light liquid pumps in ethylene oxide service that would be subject to the proposed pump requirements. Commenters stated that, using the revised emissions estimates and volume source parameters, they re-ran the EPA's risk model and calculated a baseline risk of 270-in-1 million for the Lanxess facility. The commenter stated that using the revised baseline emissions to estimate post-control emissions would result in significant reductions for either Control Option 1 or 2 and provided revised estimates of post-control emissions based on the updated data. The commenter asserted that when the EPA risk model is rerun for the Lanxess facility utilizing all corrected inputs, the residual risk is 100-in-1 million with implementation of Control Option 1. Response: In light of the additional data and comments received, the EPA has made adjustments to the emissions used in the residual risk assessment in the final rule, and we note that using revised baseline emissions to estimate post-control emissions results in significant reductions for either Control Option 1 or 2. As we acknowledged in the proposal preamble (84 FR 69186, December 17, 2019), although the EPA did not receive the CAA section 114 data from Lanxess in time to be used at proposal, we posted this data publicly to the docket at proposal to provide the public with sufficient time to review the data and provide comments during the comment period. Further, we acknowledged we intended to “use the collected information to assist the Agency in filling data gaps, establishing the baseline emissions and control levels for purposes of the regulatory reviews, identifying the most effective control measures, and estimating the environmental impacts associated with the regulatory options considered and reflected.” (84 FR 69186, December 17, 2019). Thus, as has always been our intent, we are revising the residual risk assessment to incorporate the data received in the response to the CAA section 114 request to update Lanxess' emissions in the final rule, which includes updating emissions for the storage tank and process vents to reflect the measured control efficiencies. Additionally, at proposal, the best available data had us assume that “actual” emissions were equal to “allowable” emissions. At final, the data acquired from the CAA section 114 request has allowed us to separately estimate “actual” emissions and “allowable” emissions at Lanxess. Therefore, in the final rule, we present both pre-control and post-control risks for Lanxess considering the range of emissions generated by these two emissions estimations. Additionally, we are incorporating the updated data for equipment in ethylene oxide service provided during the comment period by Lanxess in the revised risk assessment for the final rule. The updated data include component counts, hours of operation, and percentage of ethylene oxide for each process with equipment in ethylene oxide service. The EPA believes that the updated data represents the best available data because it is more recent and reflects updated component counts and changes made to the process. We considered updating the source parameters for equipment in ethylene oxide service to reflect a volume source as the commenter suggested; however, we ultimately retained the parameters as an area source based on the information already available to the EPA, and after determining such change would have minimal impact on risk. After updating emissions for this facility, the pre-control cancer risks are estimated to be 400-in-1 million (actuals) and 800-in-1 million (allowables). We disagree with the commenter's assertion that pre-control risks are 300-in-1 million based on actual emissions. At proposal and in the commenter's revisions to the modeling file, fugitive ethylene oxide emissions were grouped together and modeled as being released from one location. In their comments, Lanxess provided additional information which made it possible to accurately separate and assign these fugitive ethylene oxide emissions to their actual locations at the facility. In the modeling file for the final rule, we have separated and relocated ethylene oxide fugitive emissions to their proper location, which resulted in a risk higher than what the commenter estimated due to several fugitive areas being in closer proximity to the receptor. Therefore, in the final rule, after considering all updates made to the emissions data for Lanxess, the ethylene oxide emissions at the current level of control ( i.e., before the amended controls are applied) are estimated to be approximately 0.64 tpy based on actual emissions and 2.6 tpy based on allowable emissions, compared to 8.8 tpy at proposal. See Appendix 1 of the Residual Risk Assessment for the Miscellaneous Organic Chemical Manufacturing Source Category in Support of the 2020 Risk and Technology Review Final Rule, available in the docket for this rulemaking, for additional information. After ethylene oxide-specific controls for process vents, storage tanks, and equipment leak Control Option 1 are applied at Lanxess, ethylene oxide emissions are expected to be reduced to 0.15 tpy based on actual emissions and 0.17 tpy based on allowable emissions. Estimated post-control cancer risks are reduced to 200-in-1 million for both actual and allowable emissions estimates. We disagree with the commenter's assertion that post-control risks at Lanxess after applying controls for process vents, storage tanks, and equipment leak Control Option 1 are 100-in-1 million based on actual emissions, since the commenter did not model fugitive emissions from their actual locations as described above. In addition, Lanxess also provided updated component counts in their comments that we used to update the estimated effect that controls would have in reducing ethylene oxide emissions. These new emission reduction estimates indicate that the revised leak detection and repair (LDAR) requirements for light liquid pumps will have less of an effect in reducing ethylene oxide emissions than estimated at proposal, due to new knowledge that there are no light liquid pumps in ethylene oxide service at Lanxess. After ethylene oxide-specific controls for process vents, storage tanks, and equipment leaks Control Option 2 are applied, and using updated emissions data provided during the comment period, estimated post-control cancer risks are reduced to 100-in-1 million (actuals and allowables). We note that, after the comment period closed, the EPA met with representatives from Lanxess on March 25, 2020, to discuss their comments posted to the docket on February 20, 2020, (see Docket Item No. EPA-HQ-OAR-2018-0746-0069) and ask clarifying questions. Subsequently, Lanxess provided written responses to these questions on April 17, 2020, as well as additional updates to their February comments that included further revisions to emissions data, which would affect equipment leak emissions estimates. This data was not received in time to incorporate into the final risk modeling; however, we recognize that these changes would further reduce estimated ethylene oxide emissions from equipment leaks. Meeting minutes for the March discussion between the EPA and Lanxess, as well as the written responses Lanxess provided to questions asked at this meeting, can be found in the memorandum, Meeting Record for March 25, 2020, Meeting Between the U.S. EPA and Representatives of Lanxess Corporation, in the docket for this rulemaking. Comment: Several commenters provided input on the emissions estimates used in the risk modeling for the Huntsman Performance facility in Conroe, Texas. One commenter stated that the EPA's emissions estimates for the facility from the 2014 National Emissions Inventory (NEI) and the 2014 Toxics Release Inventory (TRI) are not appropriate for use in a risk assessment. The commenter argued that even if the NEI and TRI data were developed with adequate specificity to support risk modeling, the data are 6 years old and do not reflect current operations. The commenter provided data for the Huntsman Performance facility that they claimed more accurately reflect ethylene oxide emissions from equipment leaks, based on a detailed analysis using direct quarterly LDAR monitoring data for each relevant component. Another commenter recommended that the EPA use the information provided in Huntsman Performance's comments in the final rule because the new data more accurately reflect ethylene oxide emissions at the Huntsman Performance facility. Commenters stressed that the submitted data significantly improve on the 2014 data because they reflect physical and operating changes made since 2014, such as addition and removal of relevant equipment. One commenter explained that the new data submitted remain highly conservative and are expected to overstate actual ethylene oxide emissions, largely because the commenter's data analysis does not assume that results below the detection limit are equal to “zero” but are present at the detection limit. Some commenters stated that the EPA's modeling files incorrectly included sources at the Huntsman Performance facility that are not MON-applicable. One commenter asserted that the EPA's risk assessment for the Huntsman Performance facility incorrectly designates certain units with ethylene oxide emissions as being regulated under MON, despite the fact that they are not MON sources. Commenters also stated that the EPA specifically notes that these ethylene oxide equipment leak emissions are not entirely from MON processes; however, the EPA did not have enough information to distinguish between emissions attributed to MON processes versus other processes ( e.g., 40 CFR part 63, subparts H and PPP). The commenter specifically identified the railcar unloading fugitive area and tank farm fugitives as inappropriate to include as MON sources and provided input on why the sources do not meet the definition of MCPU or storage tank or fall within the purview of the MON. The commenter provided a copy of revised modeling they conducted with the updated emissions estimates and removal of units not subject to MON; the commenter's revised modeling results showed that residual risks associated with the Huntsman Performance facility are 40-in-1 million. Response: The EPA has reviewed the updated equipment leak emissions data provided during the comment period by Huntsman Performance in Conroe, Texas, the second highest risk-driving facility that was identified at proposal. We agree with the information provided that two emission units were incorrectly modeled as being subject to MON, when in fact, they are subject to other standards. As such, in the final rule these units are modeled at the whole facility-level only. We have also updated Huntsman Performance's ethylene oxide equipment leak emissions using the updated emissions data provided by the facility, consistent with the EPA's standard practice of using the best available data. The EPA believes that the updated data represents the best available data because it is more recent ( i.e., 2019), is based on actual emissions measurements, reflects recent physical and operating changes made to the process since the 2014 NEI emissions were reported, and conservatively considers results below the detection limit as being present at the detection limit. After considering all updates made to the emissions data for Huntsman Performance, the ethylene oxide emissions before controls are applied are estimated to be approximately 0.03 tpy based on actual and allowable emissions, compar [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%3A2020-12776. Public record. Not legal advice.