# National Emission Standards for Hazardous Air Pollutants: Surface Coating of Wood Building Products Residual Risk and Technology Review > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2018-09080 ## Record - **Collection:** Federal Register - **Document type:** Proposed Rule - **Published:** May 16, 2018 - **Citation:** 83 FR 22754 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 [EPA-HQ-OAR-2016-0678; FRL-9977-32-OAR] RIN 2060-AT71 National Emission Standards for Hazardous Air Pollutants: Surface Coating of Wood Building Products Residual Risk and Technology Review AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Surface Coating of Wood Building Products to address the results of the residual risk and technology review (RTR) that the EPA is required to conduct under the Clean Air Act (CAA). We found risks due to emissions of air toxics to be acceptable from this source category and determined that the current NESHAP provides an ample margin of safety to protect public health. We identified no new cost-effective controls under the technology review to achieve further emissions reductions. The EPA is proposing: To add an alternative compliance demonstration equation; to amend provisions addressing periods of startup, shutdown and malfunction (SSM); to amend provisions regarding electronic reporting; and to make technical and editorial changes. The EPA is proposing these amendments to improve the effectiveness of the NESHAP. This action also proposes a new EPA test method to measure isocyanate compounds in certain surface coatings. DATES: Comments. Comments must be received on or before June 15, 2018 unless a public hearing is requested by May 21, 2018. If a public hearing is requested, comments must be received on or before July 2, 2018. Under the Paperwork Reduction Act (PRA), comments on the information collection provisions are best assured of consideration if the Office of Management and Budget (OMB) receives a copy of your comments on or before June 15, 2018. Public Hearing. If a public hearing is requested by May 21, 2018, then we will hold a public hearing on May 31, 2018 at the location described in the ADDRESSES section. The last day to pre-register in advance to speak at the public hearing will be May 29, 2018. ADDRESSES: Comments. Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2016-0678, at http://www.regulations.gov. Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov. Regulations.gov is our preferred method of receiving comments. However, other submission formats are accepted. To ship or send mail via the United States Postal Service, use the following address: U.S. Environmental Protection Agency, EPA Docket Center, Docket ID No. EPA-HQ-OAR-2016-0678, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460. Use the following Docket Center address if you are using express mail, commercial delivery, hand delivery or courier: EPA Docket Center, EPA WJC West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. Delivery verification signatures will be available only during regular business hours. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Send or deliver information identified as CBI only to the following address: OAQPS Document Control Officer (C404-02), Office of Air Quality Planning and Standards, Environmental Protection Agency, Research Triangle Park, NC 27711, Attention EPA-HQ-OAR-2016-0678. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD-ROM that you mail to the EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2. For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. The EPA may publish any comment received to its public docket. Multimedia submissions (audio, video, etc. ) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( i.e., on the Web, cloud, or other file sharing system). Public Hearing. If a public hearing is requested, it will be held at the EPA's Washington DC Campus located at 1201 Constitution Avenue, NW, Washington, DC. If a public hearing is requested, then we will provide details about the public hearing on our website at: https://www.epa.gov/stationary-sources-air-pollution/surface-coating-wood-building-products-national-emission-standard-1. The EPA does not intend to publish another document in the Federal Register announcing any updates on the request for a public hearing. Please contact Ms. Aimee St. Clair at (919) 541-1063 or by email at stclair.aimee@epa.gov to request a public hearing, to register to speak at the public hearing, or to inquire as to whether a public hearing will be held. The EPA will make every effort to accommodate all speakers who arrive and register. If a hearing is held at a U.S. government facility, individuals planning to attend should be prepared to show a current, valid state- or federal-approved picture identification to the security staff in order to gain access to the meeting room. An expired form of identification will not be permitted. Please note that the Real ID Act, passed by Congress in 2005, established new requirements for entering federal facilities. If your driver's license is issued by a noncompliant state, you must present an additional form of identification to enter a federal facility. Acceptable alternative forms of identification include: Federal employee badge, passports, enhanced driver's licenses, and military identification cards. Additional information on the Real ID Act is available at https://www.dhs.gov/real-id-frequently-asked-questions. In addition, you will need to obtain a property pass for any personal belongings you bring with you. Upon leaving the building, you will be required to return this property pass to the security desk. No large signs will be allowed in the building, cameras may only be used outside of the building, and demonstrations will not be allowed on federal property for security reasons. FOR FURTHER INFORMATION CONTACT: For questions about this proposed action, contact Mr. John Bradfield, Sector Policies and Programs Division (E143-03), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-3062; fax number: (919) 541-0516; and email address: bradfield.john@epa.gov. For specific information regarding the risk modeling methodology, contact Mr. James Hirtz, 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) 541-0881; fax number: (919) 541-0840; and email address: hirtz.james@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, EPA WJC South Building (Mail Code 2221A), 1200 Pennsylvania Avenue NW, Washington DC 20460; telephone number: (202) 564-1395; and email address: cox.john@epa.gov. SUPPLEMENTARY INFORMATION: Docket. The EPA has established a docket for this rulemaking under Docket ID No. EPA-HQ-OAR-2016-0678. All documents in the docket are listed in the Regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI 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. Publicly available docket materials are available either electronically in Regulations.gov or in hard copy at the EPA Docket Center, Room 3334, EPA WJC West Building, 1301 Constitution Avenue NW, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the EPA Docket Center is (202) 566-1742. Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-2016-0678. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at http://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be CBI or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through http://www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should not include special characters or any form of encryption and be free of any defects or viruses. For additional information about the EPA's public docket, visit the EPA Docket Center homepage at http://www.epa.gov/dockets. 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: AEGL acute exposure guideline level AERMOD air dispersion model used by the HEM-3 model ANSI American National Standards Institute ASTM American Society for Testing and Materials ATSDR Agency for Toxic Substances and Disease Registry BACT best available control technology CAA Clean Air Act CalEPA California EPA CAP criteria air pollutant CBI Confidential Business Information CDX Central Data Exchange CEDRI Compliance and Emissions Data Reporting Interface CFR Code of Federal Regulations CHIEF Clearinghouse for Inventories and Emissions Factors CO catalytic oxidizers ECHO Enforcement and Compliance History Online EJ environmental justice EPA Environmental Protection Agency ERPG Emergency Response Planning Guideline ERT Electronic Reporting Tool GACT generally available control technology HAP hazardous air pollutant(s) HCl hydrochloric acid HDI hex methylene 1,6 diisocyanate HEM-3 Human Exposure Model, Version 1.1.0 HF hydrogen fluoride HI hazard index HQ hazard quotient IBR incorporation by reference ICR information collection request IRIS Integrated Risk Information System km kilometer LAER lowest achievable emission rate m 3 cubic meter MACT maximum achievable control technology MDI methylene diphenyl diisocyanate MI methyl isocyanate MIR maximum individual risk NAAQS National Ambient Air Quality Standards NAICS North American Industry Classification System NAS National Academy of Sciences NEI National Emissions Inventory NESHAP national emission standards for hazardous air pollutants No. Number NRDC Natural Resources Defense Council NTTAA National Technology Transfer and Advancement Act OAQPS Office of Air Quality Planning and Standards 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 PRA Paperwork Reduction Act QA quality assurance QC quality control RACT reasonably available control technology RBLC RACT/BACT/LAER Clearinghouse REL reference exposure level RFA Regulatory Flexibility Act RfC reference concentration RfD reference dose RTR residual risk and technology review SAB Science Advisory Board SSM startup, shutdown, and malfunction TDI 2,4 toluene diisocyanate TO thermal oxidizers TOSHI target organ-specific hazard index tpy tons per year TRI Toxics Release Inventory UF uncertainty factor UMRA Unfunded Mandates Reform Act URE unit risk estimate U.S. United States U.S.C. United States Code VCS voluntary consensus standards VOC volatile organic compounds VOHAP volatile organic hazardous air pollutants WebFIRE Web Factor Information Retrieval System XML extensible markup language 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. What should I consider as I prepare my comments for the EPA? II. Background A. What is the statutory authority for this action? B. What is this source category and how does the current NESHAP regulate its HAP emissions? C. What data collection activities were conducted to support this action? D. What other relevant background information and data are available? III. Analytical Procedures A. How do we consider risk in our decision-making? B. How do we perform the technology review? C. How did we estimate post-MACT risks posed by the source category? IV. Analytical Results and Proposed Decisions A. What are the results of the risk assessment and analyses? B. What are our proposed decisions regarding risk acceptability, ample margin of safety, and adverse environmental effects? C. What are the results and proposed decisions based on our technology review? D. What other actions are we proposing? E. What compliance dates are we proposing? V. Summary of Cost, Environmental, and Economic Impacts A. What are the affected sources? B. What are the air quality impacts? C. What are the cost impacts? D. What are the economic impacts? E. What are the benefits? VI. Request for Comments VII. Submitting Data Corrections VIII. Statutory and Executive Order Reviews A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review B. Executive Order 13771: Reducing Regulation 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 I. General Information A. Does this action apply to me? Table 1 of this preamble lists the NESHAP and associated regulated industrial source category that is the subject of this proposal. Table 1 is not intended to be exhaustive, but rather provides a guide for readers regarding the entities that this proposed action is likely to affect. The proposed standards, once promulgated, will be directly applicable to the affected sources. Federal, state, local and tribal government entities would not be affected by this proposed action. As defined in the Initial List of Categories of Sources Under Section 112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576, July 16, 1992), the “Surface Coating of Wood Building Products” source category is any facility engaged in the surface coating of wood building products. Wood building products are defined as any product that contains more than 50 percent by weight wood or wood fiber, excluding the weight of glass components, and is used in the construction, either interior or exterior, of a residential, commercial, or institutional building. This NESHAP, 40 Code of Federal regulations (CFR) part 63, subpart QQQQ, regulates all operations associated with the surface coating of wood building products, which includes preparation of the coating for application ( e.g., mixing with thinners); surface preparation of the wood building products; coating application, curing, and drying equipment; equipment cleaning; and storage, transfer, and handling of coatings, thinners, cleaning materials, and waste materials. Table 1—NESHAP and Industrial Source Categories Affected by This Proposed Action Source category NESHAP NAICS code 1 Wood Building Products Surface Coating of Wood Building Products 321211, 321212, 321218, 321219, 321911, 321999. 1 North American Industry Classification System. 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 action is available on the Internet. Following signature by the EPA Administrator, the EPA will post a copy of this proposed action at: https://www.epa.gov/stationary-sources-air-pollution/surface-coating-wood-building-products-national-emission-standard-1. Following publication in the Federal Register , the EPA will post the Federal Register version of the proposal and key technical documents at this same website. Information on the overall RTR program is available at http://www3.epa.gov/ttn/atw/rrisk/rtrpg.html. A redline version of the regulatory language that incorporates the proposed changes in this action is available in the docket for this action (Docket ID No. EPA-HQ-OAR-2016-0678). C. What should I consider as I prepare my comments for the EPA? Submitting CBI. Do not submit information containing CBI to the EPA through http://www.regulations.gov or email. Clearly mark the part or all of the information that you claim to be CBI. For CBI information on a disk or CD-ROM that you mail to the EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI. In addition to one complete version of the comments that includes information claimed as CBI, you must submit a copy of the comments that does not contain the information claimed as CBI for inclusion in the public docket. If you submit a CD-ROM or disk that does not contain CBI, mark the outside of the disk or CD-ROM clearly that it does not contain CBI. Information not marked as CBI will be included in the public docket and the EPA's electronic public docket without prior notice. Information marked as CBI will not be disclosed except in accordance with procedures set forth in 40 CFR part 2. Send or deliver information identified as CBI only to the following address: OAQPS Document Control Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, Attention Docket ID No. EPA-HQ-OAR-2016-0678. II. Background A. What is the statutory authority for this action? The statutory authority for this action is provided by sections 112 and 301 of the CAA, as amended (42 U.S.C. 7401 et seq. ). Section 112 of the CAA establishes a two-stage regulatory process to develop standards for emissions of hazardous air pollutants (HAP) from stationary sources. Generally, the first stage involves establishing technology-based standards and the second stage involves evaluating those standards that are based on maximum achievable control technology (MACT) to determine whether additional standards are needed to further address any remaining risk associated with HAP emissions. This second stage is commonly referred to as the “residual risk review.” In addition to the residual risk review, the CAA also requires the EPA to review standards set under CAA section 112 every 8 years to determine if there are “developments in practices, processes, or control technologies” that may be appropriate to incorporate into the standards. This review is commonly referred to as the “technology review.” When the two reviews are combined into a single rulemaking, it is commonly referred to as the “risk and technology review.” The discussion that follows identifies the most relevant statutory sections and briefly explains the contours of the methodology used to implement these statutory requirements. A more comprehensive discussion appears in the document titled CAA Section 112 Risk and Technology Reviews: Statutory Authority and Methodology in the docket for this rulemaking. In the first stage of the CAA section 112 standard setting process, the EPA promulgates technology-based standards under CAA section 112(d) for categories of sources identified as emitting one or more of the HAP listed in CAA section 112(b). Sources of HAP emissions are either major sources or area sources, and CAA section 112 establishes different requirements for major source standards and area source standards. “Major sources” are those that emit or have the potential to emit 10 tons per year (tpy) or more of a single HAP or 25 tpy or more of any combination of HAP. All other sources are “area sources.” For major sources, CAA section 112(d) provides that the technology-based NESHAP must reflect the maximum degree of emission reductions of HAP achievable (after considering cost, energy requirements, and non-air quality health and environmental impacts). These standards are commonly referred to as MACT standards. CAA section 112(d)(3) also establishes a minimum control level for MACT standards, known as the MACT “floor.” The EPA must also consider control options that are more stringent than the floor. Standards more stringent than the floor are commonly referred to as beyond-the-floor standards. In certain instances, as provided in CAA section 112(h), the EPA may set work practice standards where it is not feasible to prescribe or enforce a numerical emission standard. For area sources, CAA section 112(d)(5) gives the EPA discretion to set standards based on generally available control technologies or management practices (GACT standards) in lieu of MACT standards. The second stage in standard-setting focuses on identifying and addressing any remaining ( i.e., “residual”) risk according to CAA section 112(f). Section 112(f)(2) of the CAA requires the EPA to determine for source categories subject to MACT standards whether promulgation of additional standards is needed to provide an ample margin of safety to protect public health or to prevent an adverse environmental effect. CAA section 112(d)(5) provides that this residual risk review is not required for categories of area sources subject to GACT standards. Section 112(f)(2)(B) of the CAA further expressly preserves the EPA's use of the two-step approach for developing standards to address any residual risk and the Agency's interpretation of “ample margin of safety” developed in the National Emissions Standards for Hazardous Air Pollutants: Benzene Emissions from Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-Product Recovery Plants (Benzene NESHAP) (54 FR 38044, September 14, 1989). The EPA notified Congress in the Risk Report that the Agency intended to use the Benzene NESHAP approach in making CAA section 112(f) residual risk determinations (EPA-453/R-99-001, p. ES-11). The EPA subsequently adopted this approach in its residual risk determinations, and the United States Court of Appeals for the District of Columbia Circuit (the Court) upheld the EPA's interpretation that CAA section 112(f)(2) incorporates the approach established in the Benzene NESHAP. See Natural Resources Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008). The approach incorporated into the CAA and used by the EPA to evaluate residual risk and to develop standards under CAA section 112(f)(2) is a two-step approach. In the first step, the EPA determines whether risks are acceptable. This determination “considers all health information, including risk estimation uncertainty, and includes a presumptive limit on maximum individual lifetime [cancer] risk (MIR) 1 of approximately [1-in-10 thousand] [ i.e., 100-in-1 million].” 54 FR 38045, September 14, 1989. If risks are unacceptable, the EPA must determine the emissions standards necessary to bring risks to an acceptable level without considering costs. In the second step of the process, the EPA considers whether the emissions standards provide an ample margin of safety “in consideration of all health information, including the number of persons at risk levels higher than approximately 1-in-1 million, as well as other relevant factors, including costs and economic impacts, technological feasibility, and other factors relevant to each particular decision.” Id. The EPA must promulgate emission standards necessary to provide an ample margin of safety to protect public health. After conducting the ample margin of safety analysis, we consider whether a more stringent standard is necessary to prevent, taking into consideration costs, energy, safety, and other relevant factors, an adverse environmental effect. 1 Although defined as “maximum individual risk,” MIR refers only to cancer risk. MIR, one metric for assessing cancer risk, is the estimated risk if an individual were exposed to the maximum level of a pollutant for a lifetime. CAA section 112(d)(6) separately requires the EPA to review standards promulgated under CAA section 112 and revise them “as necessary (taking into account developments in practices, processes, and control technologies)” no less frequently than every 8 years. In conducting this review, which we call the “technology review,” the EPA is not required to recalculate the MACT floor. NRDC v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008); Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 2013). The EPA may consider cost in deciding whether to revise the standards pursuant to CAA section 112(d)(6). B. What is this source category and how does the current NESHAP regulate its HAP emissions? The “Surface Coating of Wood Building Products” source category includes any facility engaged in the surface coating of wood building products, which means the application of coatings using, for example, roll coaters or curtain coaters in the finishing or laminating of any wood building product that contains more than 50 percent by weight wood or wood fiber, excluding the weight of any glass components, and is used in the construction, either interior or exterior, of a residential, commercial, or institutional building. Regulated operations include all processes and process units incorporating wood building products surface coating operations. The processes include, but are not limited to, coating application production lines, emissions capture and exhaust ducting systems, cleanup stations, coating preparation stations ( e.g., mixing with thinners), surface preparation of the wood building products, curing and drying equipment; and storage, transfer, and handling of coatings, thinners, cleaning materials, and waste materials. This NESHAP, 40 CFR part 63, subpart QQQQ, regulates surface coating of wood building products (referred to in this document as the Surface Coating of Wood Building Products NESHAP). This proposal includes both a residual risk assessment and a technology review of the emission sources subject to the Surface Coating of Wood Building Products NESHAP, which includes numerical emission limits for five subcategories of wood building products: • Exterior siding and primed doorskins; • Flooring; • Interior wall paneling or tileboard; • Other interior panels; and • Doors, windows, and miscellaneous. C. What data collection activities were conducted to support this action? The EPA collected data from several environmental databases that included information pertaining to wood building products manufacturing facilities with surface coating operations in the United States. The primary databases were the Enforcement and Compliance History Online (ECHO) database, the Toxics Release Inventory (TRI), and the National Emissions Inventory (NEI) for 2011 and 2014. Title V operating permits were obtained from states that have facilities subject to 40 CFR part 63, subpart QQQQ. For more details of the title V operating permit review, see the memorandum titled Preparation of the Residual Risk Modeling Input File for Subpart QQQQ in the docket for this rulemaking (Docket ID No. EPA-HQ-OAR-2016-0678). No formal information collection request was performed. D. What other relevant background information and data are available? In addition to the ECHO, TRI, and NEI databases, the EPA reviewed the additional information sources listed below and consulted with stakeholders regulated under the Surface Coating of Wood Building Products NESHAP to determine if there have been developments in practices, processes, or control technologies by wood building products surface coating sources. These include: • Permit limits and selected compliance options from permits collected from state agencies; • Information on air pollution control options in the wood building products surface coating industry from the reasonably available control technology (RACT)/best achievable control technology (BACT)/lowest achievable emission limits (LAER) Clearinghouse (RBLC); • Information on the most effective ways to control emissions of volatile organic compounds (VOC) and volatile organic HAP (VOHAP) from sources in various industries, including the wood building products manufacturing industry; • Product Data Sheets and Material Safety Data Sheets submitted with compliance demonstrations; and • Communication with trade groups and associations representing industries in the affected NAICS categories and their members. III. Analytical Procedures In this section, we describe the analyses performed to support the proposed decisions for the RTR and other issues addressed in this proposal. A. How do we consider risk in our decision-making? As discussed in section II.A of this preamble and in the Benzene NESHAP, in evaluating and developing standards under CAA section 112(f)(2), we apply a two-step approach to determine whether or not risks are acceptable and to determine if the standards provide an ample margin of safety to protect public health. As explained in the Benzene NESHAP, “the first step judgment on acceptability cannot be reduced to any single factor” and, thus, “[t]he Administrator believes that the acceptability of risk under section 112 is best judged on the basis of a broad set of health risk measures and information.” 54 FR 38046, September 14, 1989. Similarly, with regard to the ample margin of safety determination, “the Agency again considers all of the health risk and other health information considered in the first step. Beyond that information, additional factors relating to the appropriate level of control will also be considered, including cost and economic impacts of controls, technological feasibility, uncertainties, and any other relevant factors.” Id. The Benzene NESHAP approach provides flexibility regarding factors the EPA may consider in making determinations and how the EPA may weigh those factors for each source category. The EPA conducts a risk assessment that provides estimates of the MIR posed by the HAP emissions from each source in the source category, the hazard index (HI) for chronic exposures to HAP with the potential to cause noncancer health effects, and the hazard quotient (HQ) for acute exposures to HAP with the potential to cause noncancer health effects. 2 The assessment also provides estimates of the distribution of cancer risks within the exposed populations, cancer incidence, and an evaluation of the potential for adverse environmental effects. The scope of the EPA's risk analysis is consistent with the EPA's response to comment on our policy under the Benzene NESHAP where the EPA explained that: 2 The MIR is defined as the cancer risk associated with a lifetime of exposure at the highest concentration of HAP where people are likely to live. The HQ is the ratio of the potential exposure to the HAP to the level at or below which no adverse chronic noncancer effects are expected; the HI is the sum of HQs for HAP that affect the same target organ or organ system. “[t]he policy chosen by the Administrator permits consideration of multiple measures of health risk. Not only can the MIR figure be considered, but also incidence, the presence of noncancer health effects, and the uncertainties of the risk estimates. In this way, the effect on the most exposed individuals can be reviewed as well as the impact on the general public. These factors can then be weighed in each individual case. This approach complies with the Vinyl Chloride mandate that the Administrator ascertain an acceptable level of risk to the public by employing his expertise to assess available data. It also complies with the Congressional intent behind the CAA, which did not exclude the use of any particular measure of public health risk from the EPA's consideration with respect to CAA section 112 regulations, and thereby implicitly permits consideration of any and all measures of health risk which the Administrator, in his judgment, believes are appropriate to determining what will `protect the public health'.” See 54 FR 38057, September 14, 1989. Thus, the level of the MIR is only one factor to be weighed in determining acceptability of risks. The Benzene NESHAP explained that “an MIR of approximately one in 10 thousand should ordinarily be the upper end of the range of acceptability. As risks increase above this benchmark, they become presumptively less acceptable under CAA section 112, and would be weighed with the other health risk measures and information in making an overall judgment on acceptability. Or, the Agency may find, in a particular case, that a risk that includes MIR less than the presumptively acceptable level is unacceptable in the light of other health risk factors.” Id. at 38045. Similarly, with regard to the ample margin of safety analysis, the EPA stated in the Benzene NESHAP that: “EPA believes the relative weight of the many factors that can be considered in selecting an ample margin of safety can only be determined for each specific source category. This occurs mainly because technological and economic factors (along with the health-related factors) vary from source category to source category.” Id. at 38061. We also consider the uncertainties associated with the various risk analyses, as discussed earlier in this preamble, in our determinations of acceptability and ample margin of safety. The EPA notes that it has not considered certain health information to date in making residual risk determinations. At this time, we do not attempt to quantify those HAP risks that may be associated with emissions from other facilities that do not include the source category under review, mobile source emissions, natural source emissions, persistent environmental pollution, or atmospheric transformation in the vicinity of the sources in the category. The EPA understands the potential importance of considering an individual's total exposure to HAP in addition to considering exposure to HAP emissions from the source category and facility. We recognize that such consideration may be particularly important when assessing noncancer risks, where pollutant-specific exposure health reference levels ( e.g., reference concentrations (RfCs)) are based on the assumption that thresholds exist for adverse health effects. For example, the EPA recognizes that, although exposures attributable to emissions from a source category or facility alone may not indicate the potential for increased risk of adverse noncancer health effects in a population, the exposures resulting from emissions from the facility in combination with emissions from all of the other sources ( e.g., other facilities) to which an individual is exposed may be sufficient to result in increased risk of adverse noncancer health effects. In May 2010, the Science Advisory Board (SAB) advised the EPA “that RTR assessments will be most useful to decision makers and communities if results are presented in the broader context of aggregate and cumulative risks, including background concentrations and contributions from other sources in the area.” 3 3 The EPA's responses to this and all other key recommendations of the SAB's advisory on RTR risk assessment methodologies (which is available at: http://yosemite.epa.gov/sab/sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-007-unsigned.pdf ) are outlined in a memorandum to this rulemaking docket from David Guinnup titled, EPA's Actions in Response to the Key Recommendations of the SAB Review of RTR Risk Assessment Methodologies. In response to the SAB recommendations, the EPA is incorporating cumulative risk analyses into its RTR risk assessments, including those reflected in this proposal. The Agency is (1) conducting facility-wide assessments, which include source category emission points, as well as other emission points within the facilities; (2) combining exposures from multiple sources in the same category that could affect the same individuals; and (3) for some persistent and bioaccumulative pollutants, analyzing the ingestion route of exposure. In addition, the RTR risk assessments have always considered aggregate cancer risk from all carcinogens and aggregate noncancer HI from all noncarcinogens affecting the same target organ system. Although we are interested in placing source category and facility-wide HAP risks in the context of total HAP risks from all sources combined in the vicinity of each source, we are concerned about the uncertainties of doing so. Because of the contribution to total HAP risk from emission sources other than those that we have studied in depth during this RTR review, such estimates of total HAP risks would have significantly greater associated uncertainties than the source category or facility-wide estimates. Such aggregate or cumulative assessments would compound those uncertainties, making the assessments too unreliable. B. How do we perform the technology review? Our technology review focuses on the identification and evaluation of developments in practices, processes, and control technologies that have occurred since the MACT standards were promulgated. Where we identify such developments, in order to inform our decision of whether it is “necessary” to revise the emissions standards, we analyze the technical feasibility of applying these developments and the estimated costs, energy implications, and non-air environmental impacts, and we also consider the emission reductions. In addition, we consider the appropriateness of applying controls to new sources versus retrofitting existing sources. For this exercise, we consider any of the following to be a “development”: • Any add-on control technology or other equipment that was not identified and considered during development of the original MACT standards; • Any improvements in add-on control technology or other equipment (that were identified and considered during development of the original MACT standards) that could result in additional emissions reduction; • Any work practice or operational procedure that was not identified or considered during development of the original MACT standards; • Any process change or pollution prevention alternative that could be broadly applied to the industry and that was not identified or considered during development of the original MACT standards; and • Any significant changes in the cost (including cost effectiveness) of applying controls (including controls the EPA considered during the development of the original MACT standards). In addition to reviewing the practices, processes, and control technologies that were considered at the time we originally developed (or last updated) the NESHAP, we review a variety of data sources in our investigation of potential practices, processes, or controls to consider. Among the sources we reviewed were the NESHAP for various industries that were promulgated since the MACT standards being reviewed in this action. We reviewed the regulatory requirements and/or technical analyses associated with these regulatory actions to identify any practices, processes, and control technologies considered in these efforts that could be applied to emission sources in the Surface Coating of Wood Building Products source category, as well as the costs, non-air impacts, and energy implications associated with the use of these technologies. Finally, we reviewed information from other sources, such as state and/or local permitting agency databases and industry-supported databases. C. How did we estimate post-MACT risks posed by the source category? The EPA conducted a risk assessment that provides estimates of the MIR for cancer posed by the HAP emissions from each source in the source category, the HI for chronic exposures to HAP with the potential to cause noncancer health effects, and the HQ for acute exposures to HAP with the potential to cause noncancer health effects. The assessment also provides estimates of the distribution of cancer risks within the exposed populations, cancer incidence, and an evaluation of the potential for adverse environmental effects. The seven sections that follow this paragraph describe how we estimated emissions and conducted the risk assessment. The docket for this rulemaking contains the following document which provides more information on the risk assessment inputs and models: Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule. The methods used to assess risks (as described in the seven primary steps below) are consistent with those peer-reviewed by a panel of the SAB in 2009 and described in their peer review report issued in 2010; 4 they are also consistent with the key recommendations contained in that report. 4 U.S. EPA SAB. Risk and Technology Review (RTR) Risk Assessment Methodologies: For Review by the EPA's Science Advisory Board with Case Studies—MACT I Petroleum Refining Sources and Portland Cement Manufacturing, May 2010. 1. How did we estimate actual emissions and identify the emissions release characteristics? Data were extracted from the ECHO database to determine which facilities were potentially subject to the Surface Coating of Wood Building Products NESHAP to develop a facility list. The ECHO database provides integrated compliance and enforcement information for about 800,000 regulated facilities nationwide and it allows for the search of information on permit data, inspection dates and findings, violations, and enforcement actions. For more details on ECHO, see https://echo.epa.gov/resources/general-info/learn-more-about-echo. The ECHO database identified 135 facilities as potentially subject to the Surface Coating of Wood Building Products NESHAP. Further review of the permits for these facilities found that 64 facilities have surface coating of wood building products operations, and 55 of those facilities are subject to the requirements of 40 CFR part 63, subpart QQQQ. We are interested in your comments on the development of the facility list used in our analysis. For more details on the facility list development, see the memorandum titled Preparation of the Residual Risk Modeling Input File for Subpart QQQQ in the docket for this rulemaking (Docket ID No. EPA-HQ-OAR-2016-0678). As discussed in section II.C of this preamble, we used data from facility permits, the 2014 NEI (version 1), and the TRI as the basis for the emissions used in the risk assessment for the Surface Coating of Wood Building Products source category. The NEI is a database that contains information about sources that emit criteria air pollutants (CAP), CAP precursors, and HAP. The NEI is released every 3 years based primarily on data provided by state, local, and tribal air agencies for sources in their jurisdictions and supplemented with data developed by the EPA. The NEI database includes estimates of actual annual air pollutant emissions from point and fugitive sources and emission release characteristic data, such as emission release height, temperature, diameter, velocity, and flow rates. The NEI database also includes locational latitude/longitude coordinates. For more details on the NEI, see https://www.epa.gov/air-emissions-inventories/national-emissions-inventory-nei. The TRI tracks the management of certain toxic chemicals that may pose a threat to human health and the environment through annual facility reporting of how much of each chemical is released into the environment. For more details on the TRI, see https://www.epa.gov/toxics-release-inventory-tri-program/learn-about-toxics-release-inventory. We began compiling an initial draft residual risk modeling input file for use in the Surface Coating of Wood Building Products NESHAP residual risk review in 2016. 5 We made further updates to the source category facility list to account for facilities that recently closed or reopened, added new products covered by the Surface Coating of Wood Building Products NESHAP, and/or changed their surface coating equipment or application techniques. 5 For more information, see the memorandum in the docket titled Preparation of Residual Risk Modeling Input File for Subpart QQQQ. The memorandum describes the source of the inventory data, discusses quality assurance of the 40 CFR part 63, subpart QQQQ data, provides actual versus allowable and acute risk multipliers for subpart QQQQ sources, and identifies potential outliers and suspect data for further review. We estimated actual emissions based on the 2014 NEI, preferentially, and subsequent site-specific inventory revisions provided by states or individual facilities. Where 2014 NEI data were not available for a facility, we used data from the 2011 NEI and then the 2014 TRI. Using this combination of EPA databases, we collected emissions information on the 55 sources in the category. We identified nine facilities that reported zero HAP emissions for the Surface Coating of Wood Building Products source category, and they were excluded from the risk modeling file. As a result, the risk modeling file characterized the impact of emissions from 46 sources. 6 6 Id. The total HAP emissions for the source category, which were included in the modeling file, are approximately 260 tpy. Based on the available data, the HAP emitted in the largest quantities are methanol, toluene, xylenes, ethyl benzene, methyl isobutyl ketone, glycol ethers, vinyl acetate, ethylene glycol, methyl methacrylate, formaldehyde, and dimethyl phthalate. Other than lead, persistent and bioaccumulative HAP (PB-HAP) were not reported as being emitted from this source category. Therefore, the only assessment of multipathway risk was for lead, and that assessment compared the ambient air lead concentrations to the lead National Ambient Air Quality Standard (NAAQS). Further information about the multipathway analysis performed for this category follows in section III.C.3.d. 2. How did we estimate MACT-allowable emissions? The available emissions data in the RTR emissions dataset include estimates of the mass of HAP emitted during a specified annual time period. These “actual” emission levels are often lower than the emission levels allowed under the requirements of the current MACT standards. The emissions level allowed to be emitted under the MACT standards is referred to as the “MACT-allowable” emissions level. We discussed the use of both MACT-allowable and actual emissions in the final Coke Oven Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the proposed and final Hazardous Organic NESHAP RTRs (71 FR 34428, June 14, 2006, and 71 FR 76609, December 21, 2006, respectively). In those actions, we noted that assessing the risks at the MACT-allowable level is inherently reasonable since these risks reflect the maximum level facilities could emit and still comply with national emission standards. We also explained that it is reasonable to consider actual emissions, where such data are available, in both steps of the risk analysis, in accordance with the Benzene NESHAP approach. (54 FR 38044, September 14, 1989.) Actual emissions are often lower than MACT-allowable emissions due to compliance margins, more stringent state or local rules, or over-control due to use of control technologies, equipment, or work practices that are significantly better than required to meet the NESHAP limits. However, over 90 percent of wood building products manufacturers use compliant coatings with low- or no-HAP emissions and production rate limits. We assume that coatings in the category are engineered to meet the standard with a reasonable compliance margin. For those operations, we would expect actual emissions to equal MACT-allowable emissions, because of the use of the compliant coatings and/or low-HAP coatings. Additionally, for new sources, three of five new source limits in the NESHAP are zero-HAP limits, and, as a result, we assumed that the reported actual emissions were equal to the MACT-allowable emissions for these sources since the MACT-allowable emissions are zero. For facilities using an add-on control, the operating permits indicate that the coating lines may not operate without controls. Therefore, we assumed that MACT-allowable emissions were equal to actual emissions. We are requesting comment on the assumption that actual and MACT-allowable emissions are the same for this source category. 3. How did we conduct dispersion modeling, determine inhalation exposures, and estimate individual and population inhalation risks? Both long-term and short-term inhalation exposure concentrations and health risks from the source category addressed in this proposal were estimated using the Human Exposure Model (HEM-3). The HEM-3 performs three primary risk assessment activities: (1) Conducting dispersion modeling to estimate the concentrations of HAP in ambient air, (2) estimating long-term and short-term inhalation exposures to individuals residing within 50 kilometers (km) of the modeled sources, and (3) estimating individual and population-level inhalation risks using the exposure estimates and quantitative dose-response information. a. Dispersion Modeling The air dispersion model AERMOD, used by the HEM-3 model, is one of the EPA's preferred models for assessing air pollutant concentrations from industrial facilities. 7 To perform the dispersion modeling and to develop the preliminary risk estimates, HEM-3 draws on three data libraries. The first is a library of meteorological data, which is used for dispersion calculations. This library includes 1 year (2016) of hourly surface and upper air observations from 824 meteorological stations selected to provide coverage of the United States and Puerto Rico. A second library of United States Census Bureau census block 8 internal point locations and populations provides the basis of human exposure calculations (U.S. Census, 2010). In addition, for each census block, the census library includes the elevation and controlling hill height, which are also used in dispersion calculations. A third library of pollutant-specific dose-response values is used to estimate health risks. These dose-response values are the latest values recommended by the EPA for HAP. They are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants and are discussed in more detail later in this section. 7 U.S. EPA. Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisions (70 FR 68218, November 9, 2005). 8 A census block is the smallest geographic area for which census statistics are tabulated. b. Risk From Chronic Exposure to HAP That May Cause Cancer In developing the risk assessment for chronic exposures, we used the estimated annual average ambient air concentrations of each HAP emitted by each source for which we have emissions data in the source category. The air concentrations at each nearby census block centroid were used as a surrogate for the chronic inhalation exposure concentration for all the people who reside in that census block. We calculated the MIR for each facility as the cancer risk associated with a continuous lifetime (24 hours per day, 7 days per week, 52 weeks per year, for a 70-year period) exposure to the maximum concentration at the centroid of inhabited census blocks. Individual cancer risks were calculated by multiplying the estimated lifetime exposure to the ambient concentration of each HAP (in micrograms per cubic meter (μg/m 3 )) by its unit risk estimate (URE). The URE is an upper bound estimate of an individual's probability 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, often using California EPA (CalEPA) UREs, where available. In cases where new, scientifically credible dose-response values have been developed in a manner consistent with the 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. To estimate incremental individual lifetime cancer risks associated with emissions from the facilities in the source category, the EPA summed the risks for each of the carcinogenic HAP 9 emitted by the modeled sources. Cancer incidence and the distribution of individual cancer risks for the population within 50 km of the sources were also estimated for the source category by summing individual risks. A distance of 50 km is consistent with both the analysis supporting the 1989 Benzene NESHAP (54 FR 38044, September 14, 1989) and the limitations of Gaussian dispersion models, including AERMOD. 9 The EPA classifies carcinogens as: carcinogenic to humans, likely to be carcinogenic to humans, and suggestive evidence of carcinogenic potential. These classifications also coincide with the terms “known carcinogen, probable carcinogen, and possible carcinogen,” respectively, which are the terms advocated in the EPA's Guidelines for Carcinogen Risk Assessment, published in 1986 (51 FR 33992, September 24, 1986). In August 2000, the document, Supplemental Guidance for Conducting Health Risk Assessment of Chemical Mixtures (EPA/630/R-00/002), was published as a supplement to the 1986 document. Copies of both documents can be obtained from https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing the risks of these individual compounds to obtain the cumulative cancer risks is an approach that was recommended by the EPA's SAB in their 2002 peer review of the EPA's National Air Toxics Assessment (NATA) titled NATA—Evaluating the National-scale Air Toxics Assessment 1996 Data—an SAB Advisory, available at http://yosemite.epa.gov/sab/sabproduct.nsf/214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf. c. Risk From Chronic Exposure to HAP That May Cause Health Effects Other Than Cancer To assess the risk of noncancer health effects from chronic exposure to HAP, we calculate either an HQ or a target organ-specific hazard index (TOSHI). We calculate an HQ when a single noncancer HAP is emitted. Where more than one noncancer HAP is emitted, we sum the HQ for each of the HAP that affects a common target organ system to obtain a TOSHI. The HQ is the estimated exposure divided by the chronic noncancer dose-response value, which is a value selected from one of several sources. The preferred chronic noncancer dose-response value is the EPA RfC ( https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary ), defined as “an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.” In cases where an RfC from the EPA's IRIS database is not available or where the EPA determines that using a value other than the RfC is appropriate, the chronic noncancer dose-response value can be a value from the following prioritized sources, which define their dose-response values similarly to the EPA: (1) The Agency for Toxic Substances and Disease Registry (ATSDR) Minimum Risk Level ( http://www.atsdr.cdc.gov/mrls/index.asp ); (2) the CalEPA Chronic Reference Exposure Level (REL) ( http://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0 ); or (3), as noted above, a scientifically credible dose-response value that has been developed in a manner consistent with the EPA guidelines and has undergone a peer review process similar to that used by the EPA. d. Risk From Acute Exposure to HAP That May Cause Health Effects Other Than Cancer For each HAP for which appropriate acute inhalation dose-response values are available, the EPA also assesses the potential health risks due to acute exposure. For these assessments, in order to avoid under-estimating effects, the EPA makes conservative assumptions about emission rates, meteorology, and exposure location. We use the peak hourly emission rate, 10 worst-case dispersion conditions, and, in accordance with our mandate under section 112 of the CAA, the point of highest off-site exposure to assess the potential risk to the maximally exposed individual. 10 In the absence of hourly emission data, we develop estimates of maximum hourly emission rates by multiplying the average actual annual emissions rates by a default factor (usually 10) to account for variability. This is documented in Residual Risk Assessment for Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, September, 2017 Risk and Technology Review Proposed Rule and in Appendix 5 of the report: Analysis of Data on Short-term Emission Rates Relative to Long-term Emission Rates. Both are available in the docket for this rulemaking. To characterize the potential health risks associated with estimated acute inhalation exposures to a HAP, we generally use multiple acute dose-response values, including acute RELs, acute exposure guideline levels (AEGLs), and emergency response planning guidelines (ERPG) for 1-hour exposure durations), if available, to calculate acute HQs. The acute HQ is calculated by dividing the estimated acute exposure by the acute dose-response value. For each HAP for which acute dose-response values are available, the EPA calculates acute HQs. An acute REL is defined as “the concentration level at or below which no adverse health effects are anticipated for a specified exposure duration.” 11 Acute RELs are based on the most sensitive, relevant, adverse health effect reported in the peer-reviewed medical and toxicological literature. They are designed to protect the most sensitive individuals in the population through the inclusion of margins of safety. Because margins of safety are incorporated to address data gaps and uncertainties, exceeding the REL does not automatically indicate an adverse health impact. AEGLs represent threshold exposure limits for the general public and are applicable to emergency exposures ranging from 10 minutes to 8 hours. 12 They are guideline levels for “once-in-a-lifetime, short-term exposures to airborne concentrations of acutely toxic, high-priority chemicals.” Id. at 21. The AEGL-1 is specifically defined as “the airborne concentration (expressed as ppm (parts per million) or mg/m 3 (milligrams per cubic meter)) of a substance above which it is predicted that the general population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic nonsensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure.” Airborne concentrations below AEGL-1 represent exposure levels that can produce mild and progressively increasing but transient and nondisabling odor, taste, and sensory irritation or certain asymptomatic, nonsensory effects.” Id. AEGL-2 are defined as “the airborne concentration (expressed as parts per million or milligrams per cubic meter) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape.” Id. 11 CalEPA issues acute RELs as part of its Air Toxics Hot Spots Program, and the 1-hour and 8-hour values are documented in Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The Determination of Acute Reference Exposure Levels for Airborne Toxicants, which is available at http://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary. 12 National Academy of Sciences, 2001. Standing Operating Procedures for Developing Acute Exposure Levels for Hazardous Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001. pdf. Note that the National Advisory Committee/AEGL Committee ended in October 2011, but the AEGL program continues to operate at the EPA and works with the National Academies to publish final AEGLs ( https://www.epa.gov/aegl ). ERPGs are developed for emergency planning and are intended as health-based guideline concentrations for single exposures to chemicals.” 13 Id. at 1. The ERPG-1 is defined as “the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hour without experiencing other than mild transient adverse health effects or without perceiving a clearly defined, objectionable odor.” Id. at 2. Similarly, the ERPG-2 is defined as “the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual's ability to take protective action.” Id. at 1. 13 ERPGS Procedures and Responsibilities. March 2014. American Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf. An acute REL for 1-hour exposure durations is typically lower than its corresponding AEGL-1 and ERPG-1. Even though their definitions are slightly different, AEGL-1s are often the same as the corresponding ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from our acute inhalation screening risk assessment typically result when we use the acute REL for a HAP. In cases where the maximum acute HQ exceeds 1, we also report the HQ based on the next highest acute dose-response value (usually the AEGL-1 and/or the ERPG-1). For this source category, we did not have short-term emissions data; therefore, we estimated the peak, short-term emissions using available annual emissions data from the NEI. We assumed that the peak, 1-hour emission rate could exceed a facility's annual average hourly emission rate by as much as a factor of 10, under worst-case meteorological conditions. For facilities that used compliant coatings, the default acute multiplier of 10 is overly conservative because compliant coatings result in an emissions profile that is not expected to have significant fluctuations in HAP emissions. Further review of permits found that two facilities utilizing the compliant coating approach only operate coating operations for one 8-hour shift per day, therefore, an acute multiplier of 3 was used. The default multiplier of 10 was applied to all other facilities. A further discussion of why these factors were chosen can be found in the memorandum, Preparation of the Residual Risk Modeling Input File for Subpart QQQQ, available in the docket for this rulemaking. In our acute inhalation screening risk assessment, acute impacts are deemed negligible for HAP where acute HQs are less than or equal to 1 (even under the conservative assumptions of the screening assessment), and no further analysis is performed for these HAP. In cases where an acute HQ from the screening step is greater than 1, we consider additional site-specific data to develop a more refined estimate of the potential for acute impacts of concern. For this source category, we refined our analysis by reviewing the receptor locations where the maximum HQ occurred. These refinements are discussed more fully in the Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, which is available in the docket for this source category. 4. How did we conduct the multipathway exposure and risk screening assessment? The EPA conducted a tiered screening assessment examining the potential for significant human health risks due to exposures via routes other than inhalation ( i.e., ingestion). We first determined whether any sources in the source category emitted any PB-HAP, as identified in the EPA's Air Toxics Risk Assessment Library (see Volume 1, Appendix D, at http://www2.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library ). For the Surface Coating of Wood Building Products source category, we did not identify emissions of any PB-HAP except for lead compounds, for which the lead NAAQS was applied to assess multipathway impacts. Because we did not identify PB-HAP emissions requiring further evaluation, no further evaluation of multipathway risk was conducted for this source category. In evaluating the potential multipathway risk from emissions of lead compounds, rather than developing a screening threshold emission rate, we compare maximum estimated chronic inhalation exposure concentrations with the level of the current NAAQS for lead. 14 Values below the level of the primary (health-based) lead NAAQS are considered to have a low potential for multipathway risk. 14 In doing so, the EPA notes that the legal standard for a primary NAAQS—that a standard is requisite to protect public health and provide an adequate margin of safety (CAA section 109(b))—differs from the CAA section 112(f) standard (requiring, among other things, that the standard provide an “ample margin of safety”). However, the primary lead NAAQS is a reasonable measure of determining risk acceptability ( i.e., the first step of the Benzene NESHAP analysis) since it is designed to protect the most susceptible group in the human population—children, including children living near major lead emitting sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. In addition, applying the level of the primary lead NAAQS at the risk acceptability step is conservative, since that primary lead NAAQS reflects an adequate margin of safety. For further information on the multipathway assessment approach, see the Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, which is available in the docket for this action. 5. How did we conduct the environmental risk screening assessment? a. Adverse Environmental Effects, Environmental HAP, and Ecological Benchmarks The EPA conducts a screening assessment to examine the potential for adverse environmental effects as required under section 112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines “adverse environmental effect” as “any significant and widespread adverse effect, which may reasonably be anticipated, to wildlife, aquatic life, or other natural resources, including adverse impacts on populations of endangered or threatened species or significant degradation of environmental quality over broad areas.” The EPA focuses on eight HAP, which are referred to as “environmental HAP,” in its screening assessment: six PB-HAP and two acid gases. The PB-HAP included in the screening assessment are arsenic compounds, cadmium compounds, dioxins/furans, polycyclic organic matter, mercury (both inorganic mercury and methyl mercury), and lead compounds. The acid gases included in the screening assessment are hydrochloric acid (HCl) and hydrogen fluoride (HF). The HAP that persist and bioaccumulate are of particular environmental concern because they accumulate in the soil, sediment, and water. The acid gases, HCl and HF, were included due to their well-documented potential to cause direct damage to terrestrial plants. In the environmental risk screening assessment, we evaluate the following four exposure media: Terrestrial soils, surface water bodies (includes water-column and benthic sediments), fish consumed by wildlife, and air. Within these four exposure media, we evaluate nine ecological assessment endpoints, which are defined by the ecological entity and its attributes. For PB-HAP (other than lead), both community-level and population-level endpoints are included. For acid gases, the ecological assessment evaluated is terrestrial plant communities. An ecological benchmark represents a concentration of HAP that has been linked to a particular environmental effect level. For each environmental HAP, we identified the available ecological benchmarks for each assessment endpoint. We identified, where possible, ecological benchmarks at the following effect levels: Probable effect levels, lowest-observed-adverse-effect level, and no-observed-adverse-effect level. In cases where multiple effect levels were available for a particular PB-HAP and assessment endpoint, we use all of the available effect levels to help us to determine whether ecological risks exist and, if so, whether the risks could be considered significant and widespread. For further information on how the environmental risk screening assessment was conducted, including a discussion of the risk metrics used, how the environmental HAP were identified, and how the ecological benchmarks were selected, see Appendix 9 of the Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, which is available in the docket for this action. b. Environmental Risk Screening Methodology For the environmental risk screening assessment, the EPA first determined whether any facilities in the Surface Coating of Wood Building Products source category emitted any of the environmental HAP. For the Surface Coating of Wood Building Products source category, we identified emissions of lead compounds. Because one or more of the environmental HAP evaluated are emitted by at least one facility in the source category, we proceeded to the second step of the evaluation. To evaluate the potential for adverse environmental effects from lead, we compared the average modeled air concentrations (from HEM-3) of lead around each facility in the source category to the level of the secondary NAAQS for lead. The secondary lead NAAQS is a reasonable means of evaluating environmental risk because it is set to provide substantial protection against adverse welfare effects which can include “effects on soils, water, crops, vegetation, man-made materials, animals, wildlife, weather, visibility and climate, damage to and deterioration of property, and hazards to transportation, as well as effects on economic values and on personal comfort and well-being.” 6. How did we conduct facility-wide assessments? To put the source category risks in context, we typically examine the risks from the entire “facility,” where the facility includes all HAP-emitting operations within a contiguous area and under common control. In other words, we examine the HAP emissions not only from the source category emission points of interest, but also emissions of HAP from all other emission sources at the facility for which we have data. For this source category, we conducted the facility-wide assessment using a dataset that the EPA compiled from the 2014 NEI. We used the NEI data for the facility and did not adjust any category or “non-category” data. Therefore, there could be differences in the dataset from that used for the source category assessments described in this preamble. We analyzed risks due to the inhalation of HAP that are emitted “facility-wide” for the populations residing within 50 km of each facility, consistent with the methods used for the source category analysis described above. For these facility-wide risk analyses, we made a reasonable attempt to identify the source category risks, and these risks were compared to the facility-wide risks to determine the portion of facility-wide risks that could be attributed to the source category addressed in this proposal. We also specifically examined the facility that was associated with the highest estimate of risk and determined the percentage of that risk attributable to the source category of interest. The Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, available through the docket for this action, provides the methodology and results of the facility-wide analyses, including all facility-wide risks and the percentage of source category contribution to facility-wide risks. 7. How did we consider uncertainties in risk assessment? Uncertainty and the potential for bias are inherent in all risk assessments, including those performed for this proposal. Although uncertainty exists, we believe that our approach, which used conservative tools and assumptions in order to avoid under-estimating effects, ensures that our decisions are health and environmentally protective. A brief discussion of the uncertainties in the RTR emissions dataset, dispersion modeling, inhalation exposure estimates, and dose-response relationships follows below. Also included are those uncertainties specific to our acute screening assessments, multipathway screening assessments, and our environmental risk screening assessments. A more thorough discussion of these uncertainties is included in the Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, which is available in the docket for this action. If a multipathway site-specific assessment was performed for this source category, a full discussion of the uncertainties associated with that assessment can be found in Appendix 11 of that document, Site-Specific Human Health Multipathway Residual Risk Assessment Report. a. Uncertainties in the RTR Emissions Dataset Although the development of the RTR emissions dataset involved quality assurance/quality control (QC) processes, the accuracy of emissions values will vary depending on the source of the data, the degree to which data are incomplete or missing, the degree to which assumptions made to complete the datasets are accurate, errors in emission estimates, and other factors. The emission estimates considered in this analysis generally are annual totals for certain years, and they do not reflect short-term fluctuations during the course of a year or variations from year to year. The estimates of peak hourly emission rates for the acute effects screening assessment were based on an emission adjustment factor applied to the average annual hourly emission rates, which are intended to account for emission fluctuations due to normal facility operations. b. Uncertainties in Dispersion Modeling We recognize there is uncertainty in ambient concentration estimates associated with any model, including the EPA's recommended regulatory dispersion model, AERMOD. In using a model to estimate ambient pollutant concentrations, the user chooses certain options to apply. For RTR assessments, we select some model options that have the potential to overestimate ambient air concentrations ( e.g., not including plume depletion or pollutant transformation). We select other model options that have the potential to underestimate ambient impacts ( e.g., not including building downwash). Other options that we select have the potential to either under- or overestimate ambient levels ( e.g., meteorology and receptor locations). On balance, considering the directional nature of the uncertainties commonly present in ambient concentrations estimated by dispersion models, the approach we apply in the RTR assessments should yield unbiased estimates of ambient HAP concentrations. We also note that the selection of meteorology dataset location could have an impact on the risk estimates. As we continue to update and expand our library of meteorological station data used in our risk assessments, we expect to reduce this variability. c. Uncertainties in Inhalation Exposure Assessment Although every effort is made to identify all of the relevant facilities and emission points, as well as to develop accurate estimates of the annual emission rates for all relevant HAP, the uncertainties in our emission inventory likely dominate the uncertainties in the exposure assessment. Some uncertainties in our exposure assessment include human mobility, using the centroid of each census block, assuming lifetime exposure, and assuming only outdoor exposures. For most of these factors, there is neither an under nor overestimate when looking at the maximum individual risks or the incidence, but the shape of the distribution of risks may be affected. With respect to outdoor exposures, actual exposures may not be as high if people spend time indoors, especially for very reactive pollutants or larger particles. For all factors, we reduce uncertainty when possible. For example, with respect to census-block centroids, we analyze large blocks using aerial imagery and adjust locations of the block centroids to better represent the population in the blocks. We also add additional receptor locations where the population of a block is not well represented by a single location. d. Uncertainties in Dose-Response Relationships There are uncertainties inherent in the development of the dose-response values used in our risk assessments for cancer effects from chronic exposures and noncancer effects from both chronic and acute exposures. Some uncertainties are generally expressed quantitatively, and others are generally expressed in qualitative terms. We note, as a preface to this discussion, a point on dose-response uncertainty that is stated in the EPA's 2005 Cancer Guidelines; namely, that “the primary goal of EPA actions is protection of human health; accordingly, as an Agency policy, risk assessment procedures, including default options that are used in the absence of scientific data to the contrary, should be health protective” (EPA's 2005 Cancer Guidelines, pages 1-7). This is the approach followed here as summarized in the next paragraphs. Cancer UREs used in our risk assessments are those that have been developed to generally provide an upper bound estimate of risk. That is, they represent a “plausible upper limit to the true value of a quantity” (although this is usually not a true statistical confidence limit). 15 In some circumstances, the true risk could be as low as zero; however, in other circumstances the risk could be greater. 16 Chronic noncancer RfC and reference dose (RfD) values represent chronic exposure levels that are intended to be health-protective levels. To derive dose-response values that are intended to be “without appreciable risk,” the methodology relies upon an uncertainty factor (UF) approach (U.S. EPA, 1993 and 1994) which considers uncertainty, variability, and gaps in the available data. The UFs are applied to derive dose-response values that are intended to protect against appreciable risk of deleterious effects. 15 IRIS glossary ( https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary ). 16 An exception to this is the URE for benzene, which is considered to cover a range of values, each end of which is considered to be equally plausible, and which is based on maximum likelihood estimates. Many of the UFs used to account for variability and uncertainty in the development of acute dose-response values are quite similar to those developed for chronic durations. Additional adjustments are often applied to account for uncertainty in extrapolation from observations at one exposure duration ( e.g., 4 hours) to derive an acute dose-response value at another exposure duration ( e.g., 1 hour). Not all acute dose-response values are developed for the same purpose, and care must be taken when interpreting the results of an acute assessment of human health effects relative to the dose-response value or values being exceeded. Where relevant to the estimated exposures, the lack of acute dose-response values at different levels of severity should be factored into the risk characterization as potential uncertainties. Uncertainty also exists in the selection of ecological benchmarks for the environmental risk screening assessment. We established a hierarchy of preferred benchmark sources to allow selection of benchmarks for each environmental HAP at each ecological assessment endpoint. We searched for benchmarks for three effect levels ( i.e., no-effects level, threshold-effect level, and probable effect level), but not all combinations of ecological assessment/environmental HAP had benchmarks for all three effect levels. Where multiple effect levels were available for a particular HAP and assessment endpoint, we used all of the available effect levels to help us determine whether risk exists and whether the risk could be considered significant and widespread. Although every effort is made to identify appropriate human health effect dose-response values for all pollutants emitted by the sources in this risk assessment, some HAP emitted by this source category are lacking dose-response assessments. Accordingly, these pollutants cannot be included in the quantitative risk assessment, which could result in quantitative estimates understating HAP risk. To help to alleviate this potential underestimate, where we conclude similarity with a HAP for which a dose-response value is available, we use that value as a surrogate for the assessment of the HAP for which no value is available. To the extent use of surrogates indicates appreciable risk, we may identify a need to increase priority for an IRIS assessment for that substance. We additionally note that, generally speaking, HAP of greatest concern due to environmental exposures and hazard are those for which dose-response assessments have been performed, reducing the likelihood of understating risk. Further, HAP not included in the quantitative assessment are assessed qualitatively and considered in the risk characterization that informs the risk management decisions, including consideration of HAP reductions achieved by various control options. For a group of compounds that are unspeciated ( e.g., glycol ethers), we conservatively use the most protective dose-response value of an individual compound in that group to estimate risk. Similarly, for an individual compound in a group ( e.g., ethylene glycol diethyl ether) that does not have a specified dose-response value, we also apply the most protective dose-response value from the other compounds in the group to estimate risk. e. Uncertainties in Acute Inhalation Screening Assessments In addition to the uncertainties highlighted above, there are several factors specific to the acute exposure assessment that the EPA conducts as part of the risk review under section 112 of the CAA. The accuracy of an acute inhalation exposure assessment depends on the simultaneous occurrence of independent factors that may vary greatly, such as hourly emissions rates, meteorology, and the presence of humans at the location of the maximum concentration. In the acute screening assessment that we conduct under the RTR program, we assume that peak emissions from the source category and worst-case meteorological conditions co-occur, thus, resulting in maximum ambient concentrations. These two events are unlikely to occur at the same time, making these assumptions conservative in the sense that they may over-estimate effects. We then include the additional assumption that a person is located at this point during this same time period. For this source category, these assumptions would tend to be worst-case actual exposures as it is unlikely that a person would be located at the point of maximum exposure during the time when peak emissions and worst-case meteorological conditions occur simultaneously. IV. Analytical Results and Proposed Decisions A. What are the results of the risk assessment and analyses? As described above, for the Surface Coating of Wood Building Products source category, we conducted an inhalation risk assessment for all HAP emitted, and multipathway and environmental risk screening assessments on the only PB-HAP emitted, lead. We present results of the risk assessment briefly below and in more detail in the residual risk document titled Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, which is available in the docket for this action. 1. Inhalation Risk Assessment Results Table 2 of this preamble provides an overall summary of the results of the inhalation risk assessment. As discussed in section III.C.2 of this preamble, we set MACT-allowable HAP emission levels equal to actual emissions. For more detail about the MACT-allowable emission levels, see the memorandum, Preparation of Residual Risk Modeling Input File for Subpart QQQQ, 5 which is available in the docket for this action. Table 2—Surface Coating of Wood Building Products Inhalation Risk Assessment Results 1 Risk assessment Number of facilities 2 Maximum individual cancer risk (in 1 million) 3 Estimated population at increased risk of cancer ≥1-in-1 Million Estimated annual cancer incidence (cases per year) Maximum chronic noncancer TOSHI 4 Maximum screening acute noncancer HQ 5 Source Category 46 6 800 0.0006 0.05 1 Facility-Wide 46 30 26,000 0.004 7 1 Based on actual and allowable emissions. For this source category, actual and allowable emissions are identical, so a separate risk assessment was not conducted for allowable emissions. 2 Number of facilities evaluated in the risk assessment. As described elsewhere, there are additional facilities included in the data set for the technology review. 3 Maximum individual excess lifetime cancer risk due to HAP emissions from the source category. 4 Maximum TOSHI. The target organ with the highest TOSHI for the wood building products source category is the respiratory system. 5 The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values shown use the lowest available acute threshold value, which in most cases is the REL. When an HQ exceeds 1, we also show the HQ using the next lowest available acute dose-response value. The inhalation risk modeling performed to estimate risks based on actual and allowable emissions relied primarily on emissions data from the NEI. The results of the inhalation cancer risk assessment, as shown in Table 2 of this preamble, indicate that the MIR could be up to 6-in-1 million, with formaldehyde from the melamine laminating process as the sole contributor (100 percent) to the MIR. The total estimated cancer incidence from wood building product coating sources based on actual emission levels is 0.0006 excess cancer cases per year or one case every 1,667 years, with emissions of formaldehyde (35 percent), naphthalene (27 percent), ethyl benzene (21 percent), and chromium (VI) compounds (17 percent) contributing to the cancer incidence. In addition, we estimate that approximately 800 people have cancer risks greater than or equal to 1-in-1 million. The maximum modeled chronic noncancer HI (TOSHI) value for the source category based on actual emissions is estimated to be 0.05, with emissions of formaldehyde from the melamine laminating process as the sole contributor (100 percent) to the TOSHI. The target organ affected is the respiratory system. There are not any people estimated to have exposure to HI levels greater than 1 as a result of emissions from this source category. 2. Acute Risk Results Table 2 of this preamble shows the acute risk results for this category. The screening analysis for acute impacts was based on actual emissions, and to estimate the peak emission rates from the average rates, an industry-specific multiplier of 3 was used for two facilities, and a default factor of 10 was used for the remaining facilities. The results of the acute screening analysis indicate that the maximum off-facility-site acute HQ is 1, based on the REL value for formaldehyde, and occurs at two facilities. One of these two facilities used the acute factor of 3 to characterize short-term emissions, while the other used the factor of 10. For all other HAP and facilities, acute HQ values are less than 1. Refer to the document titled Preparation of the Residual Risk Modeling Input File for Subpart QQQQ (available in the docket for this action) for a detailed description of how the acute factors were developed for this source category. For more detailed acute risk results, refer to the residual risk document titled Residual Risk Assessment for the Surface Coating of Wood Building Products Source Category in Support of the March 2018 Risk and Technology Review Proposed Rule, which is available in the docket for this action. 3. Multipathway Risk Screening Results The only PB-HAP emitted by facilities in this source category is lead. Results of the analysis for lead indicate that based on actual emissions, the maximum annual off-site ambient lead concentration was only 0.1 percent of the primary NAAQS for lead, and if the total annual emissions occurred during a 3-month period, the maximum 3-month rolling average concentration would still be only 0.5 percent of the NAAQS. Therefore, we do not expect any human health multipathway risks as a result of emissions from this source category. 4. Environmental Risk Screening Results The only environmental HAP emitted by facilities in this source category is lead. Results of the analysis for lead indicate that based on actual emissions, the maximum annual off-site ambient lead concentration was only 0.1 percent of the secondary NAAQS for lead, and if the total annual emissions occurred during a 3-month period, the maximum 3-month rolling average concentration would still be only 0.5 percent of the NAAQS. Therefore, we do not expect an adverse environmental effect as a result of HAP emissions from this source category. 5. Facility-Wide Risk Results An assessment of the facility-wide risks was performed to provide context for the source category risks, using NEI data as described above. The maximum facility-wide cancer MIR is 30-in-1 million, mainly driven by formaldehyde, chromium (VI) compounds, and nickel compounds emissions from wood drying and enamel coating operations. Wood drying is regulated under 40 CFR part 63, subpart DDDD, the Plywood and Composite Wood Products NESHAP, and enamel coating is regulated under 40 CFR part 63, subpart RRRR, the Surface Coating of Metal Furniture NESHAP. Risk and technology reviews are currently underway for both NESHAP categories. The total estimated cancer incidence from the facility-wide assessment is 0.004 excess cancer cases per year, or one excess case in every 250 years. Approximately 26,000 people are estimated to have cancer risks greater than 1-in-1 million from exposure to HAP emitted from both MACT and non-MACT sources. The maximum facility-wide TOSHI is estimated to be 7, mainly driven by emissions of acrolein from industrial processes related to wood products that are characterized as “other, not classified” in NEI. Wood drying, regulated under 40 CFR part 63, subpart DDDD, noted above, is presumably the source of the acrolein since the facilities identified as sources also dry wood. We estimate that approximately 900 people are exposed to noncancer HI levels above 1, based on facility-wide emissions. 6. What demographic groups might benefit from this regulation? To examine the potential for any environmental justice (EJ) issues that might be associated with the source category, we performed a demographic analysis, which is an assessment of risks to individual demographic groups of the populations living within 5 km and within 50 km of the facilities. In the analysis, we evaluated the distribution of HAP-related cancer and noncancer risks from the Surface Coating of Wood Building Products source category across different demographic groups within the populations living near facilities. 17 17 Demographic groups included in the analysis are: White, African American, Native American, other races and multiracial, Hispanic or Latino, children 17 years of age and under, adults 18 to 64 years of age, adults 65 years of age and over, adults without a high school diploma, people living below the poverty level, people living two times the poverty level, and linguistically isolated people. The results of the demographic analysis are summarized in Table 3 below. These results, for various demographic groups, are based on the estimated risks from actual emissions levels for the population living within 50 km of the facilities. Table 3—Surface Coating of Wood Building Products Source Category Demographic Risk Analysis Results Nationwide Population with cancer risk at or above 1-in-1 million due to wood building products surface coating Population with chronic hazard index above 1 due to wood building products surface coating Total Population 317,746,049 800 0 Race by Percent White 62 16 0 All Other Races 38 84 0 Race by Percent White 62 16 0 African American 12 75 0 Native American 0.8 0.0 0 Other and Multiracial 7 3 0 Ethnicity by Percent Hispanic 18 6 0 Non-Hispanic 82 94 0 Income by Percent Below Poverty Level 14 19 0 Above Poverty Level 86 81 0 Education by Percent Over 25 and without High School Diploma 14 25 0 Over 25 and with a High School Diploma 86 75 0 The results of the Surface Coating of Wood Building Products source category demographic analysis indicate that emissions from the source category expose approximately 800 people to a cancer risk at or above 1-in-1 million and no people to a chronic noncancer TOSHI greater than 1. The percentages of the at-risk population are greater than their respective nationwide percentages for the following demographic groups (excluding non-Hispanic): African American, people over 25 without a high school diploma, and people living below the poverty level. The other demographic groups within the exposed population were similar to or lower than the corresponding nationwide percentages. The methodology and the results of the demographic analysis are presented in a technical report, Risk and Technology Review—Analysis of Demographic Factors for Populations Living Near Wood Building Products Surface Coating Facilities, available in the docket for this action. B. What are our proposed decisions regarding risk acceptability, ample margin of safety, and adverse environmental effects? 1. Risk Acceptability As noted in section II.A of this preamble, the EPA sets standards under CAA section 112(f)(2) using “a two-step standard-setting approach, with an analytical first step to determine an ‘acceptable risk' that considers all health information, including risk estimation uncertainty, and includes a presumptive limit on MIR of “approximately 1-in-10 thousand” (54 FR 38045, September 14, 1989). We weigh all health risk factors in our risk acceptability determination, including the cancer MIR, cancer incidence, the maximum cancer TOSHI, the maximum acute noncancer HQ, the extent of noncancer risks, the distribution of cancer and noncancer risks in the exposed population, and the risk estimation uncertainties. For this risk assessment, the EPA estimated risks based on actual and allowable emissions from wood building products surface coating sources. Allowable emissions were estimated to be equal to actual emissions. The estimated inhalation cancer risk to the individual most exposed to emissions from the source category is 6-in-1-million. Approximately 800 people face an increased cancer risk greater than 1-in-1 million due to inhalation exposure to HAP emissions from this source category. The risk analysis indicates very low cancer incidence (0.0006 excess cancer cases per year, or one excess case every 1,667 years), as well as low potential for adverse chronic noncancer health effects. The acute screening assessment indicates no pollutants or facilities exceeding an HQ value of 1. Therefore, we find there is little potential concern of acute noncancer health impacts. In evaluating the potential for multipathway effects from emissions of lead from the source category, the risk assessment indicates no significant potential for multipathway effects. Considering all of the health risk information and factors discussed above, including the uncertainties discussed in section III of this preamble, the EPA proposes that the risks from the Surface Coating of Wood Building Products source category are acceptable. 2. Ample Margin of Safety Analysis and Proposed Controls As directed by CAA section 112(f)(2), we conducted an analysis to determine if the current emissions standards provide an ample margin of safety to protect public health. Under the ample margin of safety analysis, the EPA considers all health factors evaluated in the risk assessment and evaluates the cost and feasibility of available control technologies and other measures (including the controls, measures, and costs reviewed under the technology review) that could be applied to this source category to further reduce the risks (or potential risks) due to emissions of HAP identified in our risk assessment. In this analysis, we considered the results of the technology review, risk assessment, and other aspects of our MACT rule review to determine whether there are any cost-effective controls or other measures that would reduce emissions further to provide an ample margin of safety with respect to the risks associated with these emissions. Although we are proposing that the risks from this source category are acceptable, risk estimates for approximately 800 people in the exposed population are above 1-in-1 million, caused by formaldehyde emissions from one facility. The maximum acute risk is an HQ of 1 also caused by formaldehyde. As a result, we further considered whether the MACT standards for this source category provide an ample margin of safety to protect public health. Our technology review did not identify any new practices, controls, or process options that are being used in this industry, or in other industries, that would be cost effective and result in further reduction of formaldehyde emissions. 18 Our review of the operating permits for major sources subject to the Surface Coating of Wood Building Products MACT did not reveal any facilities with limits set below the current new or existing source limits (Tables 1 and 2, 40 CFR part 63, subpart QQQQ). Limits set below the current standards would have been an indication that improved controls or lower emission compliant coatings were available. As discussed in the technology review memorandum, our review of the RACT/BACT/LAER Clearinghouse (RBLC) identified three sources that are potentially covered under 40 CFR part 63, subpart QQQQ, but none contained new control methods. 18 Technology Review for the Surface Coating of Wood Building Products Source Category—Proposed Rule; see Docket ID No. EPA-HQ-OAR-2016-0678. Because no new controls, technologies, processes, or work practices were identified to reduce formaldehyde emissions and the risk assessment determined that the health risks associated with HAP emissions remaining after implementation of the Surface Coating of Wood Building Products MACT were acceptable, we are proposing that the current standards protect public health with an ample margin of safety. 3. Adverse Environmental Effects The emissions data for this source category indicate the presence of one environmental HAP, lead, emitted by sources within this source category. Based on the results of our environmental risk screening assessment, we conclude that there is not an adverse environmental effect as a result of HAP emissions from the Surface Coatings of Wood Building Products source category. 19 Thus, we are proposing that it is not necessary to set a more stringent standard. 19 The environmental screening analysis is documented in Residual Risk Assessment for Wood Building Products Surface Coating Sources in Support of the February 2018 Risk and Technology Review Proposed Rule, in the docket for this action. C. What are the results and proposed decisions based on our technology review? 1. How did we evaluate technological developments? Section 112(d)(6) of the CAA requires a review of “developments in practices, processes and control technologies” in each source category as part of the technology review process. For this technology review, the “developments” we consider include: • Add-on control technology that was not identified during the NESHAP development; • improvement to an existing add-on control technology resulting in significant additional HAP emissions reductions; • work practice or operational procedure that was not previously identified; • process change or pollution prevention alternative that was not identified; or • a coating formulation or application technique that was not previously identified. 2. What was our analysis and conclusions regarding technological developments? Our review of the developments in technology for the Surface Coating of Wood Building Products source category did not reveal any changes that require revisions to the emission standards. In the original NESHAP, it was noted that “the most prevalent form of emission control for surface coating of wood building products is the use of low-VOC and low-HAP coatings, such as waterborne or ultraviolet-cured coatings.” 20 20 Preliminary Industry Characterization: Wood Building Products Surface Coating. Publication No. EPA-453/R-00-004. September 1998. Available at https://www3.epa.gov/airtoxics/coat/flatw/wbppic.pdf. Our review did not identify any new or improved add-on control technology, any new work practices, operational procedures, process changes, or new pollution prevention approaches that reduce emissions in the category that have been implemented at wood building products surface coating operations since promulgation of the current NESHAP. Consequently, we propose that no revisions to the NESHAP are necessary pursuant to CAA section 112(d)(6). D. What other actions are we proposing? In addition to the proposed determinations described above, we are proposing additional revisions. We are proposing revisions to the SSM provisions of the MACT rule 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 sources from the requirement to comply with otherwise applicable CAA section 112(d) emission standards during periods of SSM. We also are proposing various other changes, including an alternative compliance calculation, electronic submittal of notifications, compliance reports, and performance test reports, a new EPA test method, incorporation by reference (IBR) of several test methods (listed in section IV.D.5 below), and various technical and editorial changes. Additionally, we are requesting comment on repeat emissions testing requirements for facilities that demonstrate compliance with the standards using add-on control devices. Our analyses and proposed changes related to these issues are discussed in sections IV.D.1 through 6 of this preamble. 1. Startup, Shutdown, and Malfunction 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 exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section 302(k) of the CAA, emissions standards or limitations must be continuous in nature and that the SSM exemption violates the CAA's requirement that some CAA section 112 standards apply continuously. We are proposing the elimination of the SSM exemption in this rule, which appears at 40 CFR 63.4700, 40 CFR 63.4720, and in Table 4 to Subpart QQQQ of Part 63. Consistent with Sierra Club v. EPA, we are proposing standards in this rule that apply at all times. We are also proposing several revisions to Table 4 (the General Provisions Applicability Table) as is explained in more detail below. For example, we are proposing to eliminate the incorporation of the General Provisions' requirement that the source develop an SSM plan. We also are proposing to eliminate and revise certain recordkeeping and reporting requirements related to the SSM exemption as further described below. The EPA has attempted to ensure that the provisions we are proposing to eliminate are inappropriate, unnecessary, or redundant in the absence of the SSM exemption. We are specifically seeking comment on whether we have successfully done so. The EPA believes the removal of the SSM exemption creates no additional burden to facilities regulated under the Surface Coating of Wood Building Products NESHAP. Deviations currently addressed by a facility's SSM Plan are required to be reported in the Semiannual Compliance Report, a requirement that remains under the proposal (40 CFR 63.4720). Facilities will no longer need to develop an SSM Plan or keep it current (Table 4, 40 CFR part 63, subpart QQQQ). Facilities will also no longer have to file special SSM reports for deviations not described in the their SSM Plan [40 CFR 63.4720(c)(2)]. We are specifically seeking comment on whether we have successfully removed SSM exemptions without adding unforeseen burden. Periods of startup and shutdown. In proposing the standards in this rule, the EPA has taken into account startup and shutdown periods and, for the reasons explained below, is not proposing alternate standards for those periods. For add-on control systems, the Surface Coating of Wood Building Products NESHAP requires the measurement of thermal oxidizer (TO) operating temperature or catalytic oxidizer (CO) average temperature across the catalyst bed as well as other types of parameter monitoring. Parameter limits apply at all times, including during periods of startup and shutdown. The Surface Coating of Wood Building Products NESHAP requires TO or CO operating temperature and other add-on control device operating parameters to be recorded at least once every 15 minutes. The Surface Coating of Wood Building Products NESHAP specifies in 40 CFR 63.4763(c) that if an operating parameter is out of the allowed range, this is a deviation from the operating limit and must be reported as specified in 40 CFR 63.4710(c)(6) and 63.4720(a)(7). Our permit review of the facilities using add-on control as a compliance approach indicated that all were required, by permit, to have their control system in operation during all time periods when coating processes were operational. The rule requires compliance based on a 12-month rolling average emissions calculation. Periods of startup and shutdown are included, but, because of operational requirements in the category, are a very small component of the emissions calculation. Therefore, we are not proposing separate standards for startup and/or shutdown periods. Periods of malfunction. Periods of startup, normal operations, and shutdown are all predictable and routine aspects of a source's operations. Malfunctions, in contrast, are neither predictable nor routine. Instead they are, by definition, sudden, infrequent, and not reasonably preventable failures of emissions control, process or monitoring equipment. (40 CFR 63.2, definition of malfunction). 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 and this reading has been upheld as reasonable by the Court in U.S. Sugar Corp. v. EPA, 830 F.3d 579, 606-610 (2016). Under CAA section 112, emissions standards for new sources must be no less stringent than the level “achieved” by the best controlled similar source and for existing sources generally must be no less stringent than the average emission limitation “achieved” by the best performing 12 percent of sources in the category. There is nothing in CAA section 112 that directs the Agency to consider malfunctions in determining the level “achieved” by the best performing sources when setting emission standards. As the Court has recognized, the phrase “average emissions limitation achieved by the best performing 12 percent of” sources “says nothing about how the performance of the best units is to be calculated.” National Association of Clean Water Agencies v. EPA, 734 F.3d 1115, 1141 (D.C. Cir. 2013). While the EPA accounts for variability in setting emissions standards, nothing in CAA section 112 requires the Agency to consider malfunctions as part of that analysis. The EPA is not required to treat a malfunction in the same manner as the type of variation in performance that occurs during routine operations of a source. A malfunction is a failure of the source to perform in “normal or usual manner,” and no statutory language compels the EPA to consider such events in setting CAA section 112 standards. As the Court recognized in U.S. Sugar Corporation, accounting for malfunctions in setting standards would be difficult, if not impossible, given the myriad different types of malfunctions that can occur across all sources in the category and given the difficulties associated with predicting or accounting for the frequency, degree, and duration of various malfunctions that might occur. Id. at 608 (“the EPA would have to conceive of a standard that could apply equally to the wide range of possible boiler malfunctions, ranging from an explosion to minor mechanical defects. Any possible standard is likely to be hopelessly generic to govern such a wide array of circumstances.”) As such, the performance of units that are malfunctioning is not “reasonably” foreseeable. See, e.g., Sierra Club v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999) (“The EPA typically has wide latitude in determining the extent of data-gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to `invest the resources to conduct the perfect study.'”) See also, Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978) (“In the nature of things, no general limit, individual permit, or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by `uncontrollable acts of third parties,' such as strikes, sabotage, operator intoxication or insanity, and a variety of other eventualities, must be a matter for the administrative exercise of case-by-case enforcement discretion, not for specification in advance by regulation.”). In addition, emissions during a malfunction event can be significantly higher than emissions at any other time of source operation. For example, if an air pollution control device with 99-percent removal goes off-line as a result of a malfunction (as might happen if, for example, the bags in a baghouse catch fire) and the emission unit is a steady state type unit that would take days to shut down, the source would go from 99-percent control to zero control until the control device was repaired. The source's emissions during the malfunction would be 100 times higher than during normal operations. As such, the emissions over a 4-day malfunction period would exceed the annual emissions of the source during normal operations. As this example illustrates, accounting for malfunctions could lead to standards that are not reflective of (and significantly less stringent than) levels that are achieved by a well-performing non-malfunctioning source. It is reasonable to interpret CAA section 112 to avoid such a result. The EPA's approach to malfunctions is consistent with CAA section 112 and is a reasonable interpretation of the statute. Although no statutory language compels the EPA to set standards for malfunctions, the EPA has the discretion to do so where feasible. For example, in the Petroleum Refinery Sector RTR, the EPA established a work practice standard for unique types of malfunction that result in releases from pressure relief devices or emergency flaring events because information was available to determine that such work practices reflected the level of control that applies to the best performing sources. 80 FR 75178, 75211-14 (December 1, 2015). The EPA will consider whether circumstances warrant setting work practice standards for a particular type of malfunction and, if so, whether the EPA has sufficient information to identify the relevant best performing sources and establish a standard for such malfunctions. We also encourage commenters to provide any such information. In the event that a source fails to comply with the applicable CAA section 112(d) standards as a result of a malfunction event, the EPA would determine an appropriate response based on, among other things, the good faith efforts of the source to minimize emissions during malfunction periods, including preventative and corrective actions, as well as root cause analyses to ascertain and rectify excess emissions. The EPA would also consider whether the source's failure to comply with the CAA section 112(d) standard was, in fact, sudden, infrequent, not reasonably preventable and was not instead caused in part by poor maintenance or careless operation. 40 CFR 63.2 (definition of malfunction). If the EPA determines in a particular case that an enforcement action against a source for violation of an emission standard is warranted, the source can raise any and all defenses in that enforcement action and the federal district court will determine what, if any, relief is appropriate. The same is true for citizen enforcement actions. Similarly, the presiding officer in an administrative proceeding can consider any defense raised and determine whether administrative penalties are appropriate. In summary, the EPA interpretation of the CAA and, in particular, CAA section 112 is reasonable and encourages practices that will avoid malfunctions. Administrative and judicial procedures for addressing exceedances of the standards fully recognize that violations may occur despite good faith efforts to comply and can accommodate those situations. U.S. Sugar Corporation v. EPA, 830 F.3d 579, 606-610 (2016). a. General Duty We are proposing to revise the General Provisions table (Table 4) entry for 40 CFR 63.6(e)(1)-(2) by redesignating it as 40 CFR 63.6(e)(1)(i) and changing the “yes” in column 3 to a “no.” Section 63.6(e)(1)(i) describes the general duty to minimize emissions. Some of the language in that section is no longer necessary or appropriate considering the elimination of the SSM exemption. We are proposing instead to add general duty regulatory text at 40 CFR 63.4700(b) that reflects the general duty to minimize emissions while eliminating the reference to periods covered by an SSM exemption. The current language in 40 CFR 63.6(e)(1)(i) characterizes what the general duty entails during periods of SSM. With the elimination of the SSM exemption, there is no need to differentiate between normal operations and SSM events in describing the general duty. Therefore, the language the EPA is proposing for 40 CFR 63.4700(b) does not include that language from 40 CFR 63.6(e)(1). We are also proposing to revise the General Provisions table (Table 4) to add an entry for 40 CFR 63.6(e)(1)(ii) and include a “no” in column 3. Section 63.6(e)(1)(ii) imposes requirements that are not necessary with the elimination of the SSM exemption or are redundant with the general duty requirement being added at 40 CFR 63.4700(b). We are also proposing to revise the General Provisions table (Table 4) to add an entry for 40 CFR 63.6(e)(1)(iii) and include a “yes” in column 3. Finally, we are proposing to revise the General Provisions table (Table 4) to add an entry for 40 CFR 63.6(e)(2) and include a “no” in column 3. This paragraph is reserved and is not applicable to 40 CFR part 63, subpart QQQQ. b. SSM Plan We are proposing to revise the General Provisions table (Table 4) to add an entry for 40 CFR 63.6(e)(3) and include a “no” in column 3. Generally, these paragraphs require development of an SSM plan and specify SSM recordkeeping and reporting requirements related to the SSM plan. As noted, the EPA is proposing to remove the SSM exemptions. Therefore, affected units will be subject to an emission standard during such events. The applicability of a standard during such events will ensure that sources have ample incentive to plan for and achieve compliance, and, thus, the SSM plan requirements are no longer necessary. c. Compliance With Standards We are proposing to revise the General Provisions table (Table 4) entries for 40 CFR 63.6(f) and (h) by re-designating these sections as 40 CFR 63.6(f)(1) and [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%3A2018-09080. Public record. Not legal advice.