# National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2010-21102 ## Record - **Collection:** Federal Register - **Document type:** Rule - **Published:** September 9, 2010 - **Citation:** 75 FR 54970 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 60 and 63 [EPA-HQ-OAR-2002-0051; EPA-HQ-OAR-2007-0877; FRL-9189-2] RIN 2060-AO15, 2060-AO42 National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) from the Portland Cement Manufacturing Industry and to the New Source Performance Standards (NSPS) for Portland Cement Plants. The final amendments to the NESHAP add or revise, as applicable, emission limits for mercury, total hydrocarbons (THC), and particulate matter (PM) from new and existing kilns located at major and area sources, and for hydrochloric acid (HCl) from new and existing kilns located at major sources. The standards for new kilns apply to facilities that commence construction, modification, or reconstruction after May 6, 2009. The final amendments to the NSPS add or revise, as applicable, emission limits for PM, opacity, nitrogen oxides (NO X ), and sulfur dioxide (SO 2 ) for facilities that commence construction, modification, or reconstruction after June 16, 2008. The final rule also includes additional testing and monitoring requirements for affected sources. DATES: These final rules are effective on November 8, 2010. The incorporation by reference of certain publications listed in this rule is approved by the Director of the Federal Register on November 8, 2010. ADDRESSES: EPA has established two separate dockets for these actions: Docket ID No. EPA-HQ-OAR-2007-0877 for the amendments to the NSPS and Docket ID No. EPA-HQ-OAR-2002-0051 for the amendments to the NESHAP. All documents in the two dockets are listed in the http://www.regulations.gov index. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at the EPA Docket Center, Standards of Performance for Portland Cement Plants Docket, EPA West, Room 3334, 1301 Constitution Ave., 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 Docket Center is (202) 566-1742. FOR FURTHER INFORMATION CONTACT: Mr. Keith Barnett; Office of Air Quality Planning and Standards; Sector Policies and Programs Division, Metals and Minerals Group (D243-02); Environmental Protection Agency; Research Triangle Park, NC 27711; telephone number: (919) 541-5605; fax number: (919) 541-5450; e-mail address: barnett.keith@epa.gov. SUPPLEMENTARY INFORMATION: The supplementary information presented 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? C. Judicial Review II. Background Information on the NESHAP, 40 CFR Part 63, Subpart LLL A. What is the statutory basis for the NESHAP in 40 CFR part 63, subpart LLL? B. Summary of the National Lime Association v. EPA Litigation C. EPA's Response to the Remand D. Reconsideration of EPA Final Action in Response to the Remand III. Background Information From the NSPS 40 CFR Part 60, Subpart F IV. Summary of EPA's Final Action on Amendments A. What are EPA's final actions on 40 CFR part 63, subpart LLL? B. What are EPA's final actions on 40 CFR part 60, subpart F? C. What is EPA's sector-based approach? V. Responses to Major Comments A. What are the significant comments and responses on 40 CFR part 63, subpart LLL? B. What are the significant comments and responses on 40 CFR part 60, subpart F? VI. Summary of Cost, Environmental, Energy, and Economic Impacts of the Final Amendments to Subpart LLL and Subpart F VII. Statutory and Executive Order Reviews A. Executive Order 12866: Regulatory Planning and Review B. Paperwork Reduction Act C. Regulatory Flexibility Act D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer Advancement Act J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations K. Congressional Review Act I. General Information A. Does this action apply to me? Categories and entities potentially regulated by this final rule include: Category NAICS code 1 Examples of regulated entities Industry 327310 Portland cement manufacturing plants. Federal government Not affected. State/local/Tribal government Portland cement manufacturing plants. 1 North American Industry Classification System. This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. To determine whether your facility will be regulated by this action, you should examine the applicability criteria in 40 CFR 60.60 (subpart F) or in 40 CFR 63.1340 (subpart LLL). If you have any questions regarding the applicability of this final action to a particular entity, contact the person listed in the preceding FOR FURTHER INFORMATION CONTACT section. B. Where can I get a copy of this document? In addition to being available in the docket, an electronic copy of this final action is available on the Worldwide Web (WWW) through the Technology Transfer Network (TTN). Following signature, a copy of this final action will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules at http://www.epa.gov/ttn/oarpg. The TTN provides information and technology exchange in various areas of air pollution control. C. Judicial Review Under section 307(b)(1) of the Clean Air Act (CAA), judicial review of these final rules are available only by filing a petition for review in the United States Court of Appeals for the District of Columbia Circuit by November 8, 2010. Under section 307(b)(2) of the CAA, the requirements established by these final rules may not be challenged separately in any civil or criminal proceedings brought by EPA to enforce these requirements. Section 307(d)(7)(B) of the CAA further provides that “[o]nly an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment (including any public hearing) may be raised during judicial review.” This section also provides a mechanism for EPA to convene a proceeding for reconsideration, “[i]f the person raising an objection can demonstrate to EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after the period for public comment (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” Any person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC 20460, with a copy to both the person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT section, and the Associate General Counsel for the Air and Radiation Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave., NW., Washington, DC 20460. II. Background Information on the NESHAP, 40 CFR Part 63, Subpart LLL A. What is the statutory basis for the NESHAP in 40 CFR part 63, subpart LLL? Section 112 of the CAA establishes a regulatory process to address emissions of hazardous air pollutants (HAP) from stationary sources. After EPA has identified categories of sources emitting one or more of the HAP listed in section 112(b) of the CAA, section 112(d) requires us to promulgate NESHAP for those sources. For “major sources” 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 a combination of HAP, these technology-based standards must reflect the maximum reductions of HAP achievable (after considering cost, energy requirements, and non-air quality health and environmental impacts) and are commonly referred to as maximum achievable control technology (MACT) standards. The statute specifies certain minimum stringency requirements for MACT standards, which are referred to as “floor” requirements. See CAA section 112(d)(3). Specifically, for new sources, the MACT floor cannot be less stringent than the emission control that is achieved in practice by the best controlled similar source. The MACT standards for existing sources can be less stringent than standards for new sources, but they cannot be less stringent than the average emission limitation achieved by the best-performing 12 percent of existing sources (for which the Administrator has emissions information) in the category or subcategory (or the best-performing five sources for categories or subcategories with fewer than 30 sources). In developing MACT, we must also consider control options that are more stringent than the floor. We may establish standards more stringent than the floor based on the consideration of the cost of achieving the emissions reductions, any non-air quality health and environmental impacts, and energy requirements. CAA section 112(d)(2). Section 112(k)(3)(B) of the CAA requires EPA to identify at least 30 HAP that pose the greatest potential health threat in urban areas, and section 112(c)(3) requires EPA to regulate, under section 112(d) standards, the area source 1 categories that represent 90 percent of the emissions of the 30 “listed” HAP (“urban HAP”). We implemented these listing requirements through the Integrated Urban Air Toxics Strategy (64 FR 38715, July 19, 1999). 2 1 An area source is a stationary source of HAP emissions that is not a major source. A major source is a stationary source that emits or has the potential to emit 10 tpy or more of any HAP or 25 tpy or more of any combination of HAP. 2 Since its publication in the Integrated Urban Air Toxics Strategy in 1999, EPA has amended the area source category list several times. The Portland cement manufacturing source category was listed for regulation under this 1999 Urban Strategy based on emissions of arsenic, cadmium, beryllium, lead, and polychlorinated biphenyls (PCB). The final NESHAP for the Portland Cement Manufacturing Industry (64 FR 31898, June 14, 1999) included emission limits based on performance of MACT for the control of THC emissions from area sources. This 1999 rule fulfills the requirement to regulate area source cement kiln emissions of PCB (for which THC is a surrogate). However, EPA did not include requirements for the control of the non-volatile metal HAP (arsenic, cadmium, beryllium, and lead) from area sources in the 1999 rule or in the 2006 amendments. To fulfill our requirements under CAA section 112(c)(3) and 112(k), EPA is thus setting emissions standards for these metal HAP from Portland cement manufacturing facilities that are area sources (using PM as a surrogate). In this final rule EPA is promulgating PM standards for area sources based on performance of MACT, PM being a surrogate for these (and other non-volatile) HAP metals. Section 112(c)(6) requires that EPA list categories and subcategories of sources assuring that sources accounting for not less than 90 percent of the aggregate emissions of each of seven specified HAP are subject to standards under section 112(d)(2) or (d)(4). The seven HAP are as follows: Alkylated lead compounds; polycyclic organic matter; hexachlorobenzene; mercury; polychlorinated byphenyls; 2,3,7,8-tetrachlorodibenzofurans; and 2,3,7,8-tetrachloroidibenzo-p-dioxin. Standards established under CAA section 112(d)(2) must reflect the performance of MACT. “Portland cement manufacturing: Non-hazardous waste kilns” is listed as a source category pursuant to CAA section 112(c)(6) due to emissions of polycyclic organic matter (POM), mercury, and dioxin/furans. Consistent with the requirements of CAA section 112(c)(6), we set MACT standards for these pollutants. 63 FR 17838, 17848, April 10, 1998; see also 63 FR at 14193 (March 24, 1998) (area source cement kilns' emissions of mercury, dibenzo-p-dioxins and dibenzo-p-furans, POM, and PCB are subject to MACT). Section 129(a)(1)(A) of the CAA requires EPA to establish specific performance standards, including emission limitations, for “solid waste incineration units” generally, and, in particular, for “solid waste incineration units combusting commercial or industrial waste” (CAA section 129(a)(1)(D)). 3 3 CAA section 129 refers to the Solid Waste Disposal Act (SWDA). However, this Act, as amended is commonly referred to as RCRA. Section 129 of the CAA defines “solid waste incineration unit” as “a distinct operating unit of any facility which combusts any solid waste material from commercial or industrial establishments or the general public.” CAA Section 129(g)(1). CAA Section 129 also provides that “solid waste” shall have the meaning established by EPA pursuant to its authority under the Resource Conservation and Recovery Act (RCRA). Section 129(g)(6). In Natural Resources Defense Council v. EPA, 489 F. 3d 1250, 1257-61 (DC Cir. 2007), the Court vacated the Commercial and Industrial Solid Waste Incineration Units (CISWI) Definitions Rule, 70 FR 55568 (Sept. 22, 2005), which EPA issued pursuant to CAA section 129(a)(1)(D). In response to the Court's remand and vacatur of the CISWI Definitions rule, EPA initiated a rulemaking to identify which secondary materials are non-hazardous “solid waste” for purposes of subtitle D (non-hazardous waste) of the RCRA when burned in a combustion unit. See 75 FR 31844 (June 4, 2010). Any final definition adopted in that rulemaking, in turn, will determine the applicability of CAA section 129(a) ( i.e., any combustion unit that burns any non-hazardous secondary material that is considered to be a solid waste would be subject to CAA section 129 requirements). There is presently no Federal regulatory interpretation of “solid waste” for EPA to apply under Subtitle D of RCRA for purposes of CAA section 112 and 129. EPA is not prejudging, and cannot prejudge the outcome of the recently proposed non-hazardous solid waste rulemaking. EPA therefore cannot reliably determine at this time if the non-hazardous secondary materials combusted by cement kilns are to be classified as solid wastes. Accordingly, EPA is basing all determinations as to source classification on the emissions information now available, as required by CAA section 112(d)(3), and will necessarily continue to do so until the solid waste definition discussed above is promulgated. The current data base classifies all Portland cement kilns as CAA section 112 sources ( i.e., subject to regulation under CAA section 112). We proposed amendments to the Portland Cement Manufacturing NESHAP on May 6, 2009. See 74 FR 21136. We received a total of 3,229 comments from the Portland cement industry, environmental groups, State environmental agencies and others during the comment period. This final rule reflects our consideration of all the comments we received. Detailed responses to the comments not included in this preamble are contained in the Summary of Public Comments and Responses document, which is included in the docket for this rulemaking. B. Summary of the National Lime Association v. EPA Litigation On June 14, 1999 (64 FR 31898), EPA issued the NESHAP for the Portland Cement Manufacturing Industry (40 CFR part 63, subpart LLL). 4 The 1999 final rule established emission limitations for PM as a surrogate for non-volatile HAP metals (major sources only), dioxins/furans, and for greenfield 5 new sources total THC as a surrogate for organic HAP. These standards were intended to be based on the performance of MACT pursuant to CAA sections 112(d)(2) and (3). We did not establish limits for THC for existing sources and non-greenfield new sources, nor for HCl or mercury for new or existing sources. We reasoned that emissions of these constituents were a function of raw material concentrations and so were essentially uncontrolled, the result being that there was no level of performance on which a floor could be based. EPA further found that beyond the floor standards for these HAP were not warranted. 4 Cement kilns which burn hazardous waste are a separate source category, since their emissions of many HAP differ from Portland cement kilns' as a result of the hazardous waste inputs. Rules for hazardous waste-burning cement kilns are found at subpart EEE of part 63. 5 For purposes of the 1999 rule a new greenfield kiln is a kiln constructed after March 24, 1998, at a site where there are no existing kilns. Ruling on petitions for review of various environmental groups, the DC Circuit held that EPA had erred in failing to establish CAA section 112(d) standards for mercury, THC (except for greenfield new sources) and HCl. The court held that “[n]othing in the statute even suggests that EPA may set emission levels only for those * * * HAPs controlled with technology.” National Lime Ass'n v. EPA, 233 F. 3d 625, 633 (DC Cir. 2000). The court also stated that EPA is obligated to consider other pollution-reducing measures such as process changes and material substitution. Id. at 634 (“the absence of technology-based pollution control devices for HCl, mercury, and total hydrocarbons did not excuse EPA from setting emission standards for those pollutants”). Later cases go on to hold that EPA must account for levels of HAP in raw materials and other inputs in establishing MACT floors, and further hold that sources with low HAP emission levels due to low levels of HAP in their raw materials can be considered best performers for purposes of establishing MACT floors. See, e.g., Cement Kiln Recycling Coalition v. EPA, 255 F. 2d 855, 865-66 (DC Cir. 2001); Sierra Club v. EPA (“Brick MACT”), 479 F. 3d 875, 882-83 (DC Cir. 2007). 6 6 In the remainder of the opinion, the Court in National Lime Ass'n upheld EPA's standards for PM and dioxin (on grounds that petitioner had not properly raised arguments in its opening brief), upheld EPA's use of PM as a surrogate for HAP metals, and remanded for further explanation EPA's choice of an analytic method for HCl. C. EPA's Response to the Remand In response to the National Lime Ass'n mandate, on December 2, 2005, we proposed standards for mercury, THC, and HCl. (More information on the regulatory and litigation history may be found at 70 FR 72332, December 2, 2005.) We received over 1,700 comments on the proposed amendments. Most of these comments addressed the lack of a mercury emission limitation in the proposed amendments. On December 20, 2006 (71 FR 76518), EPA published final amendments to the NESHAP. The 2006 amendments contained a new source standard for mercury emissions from cement kilns and kilns/in-line raw mills of 41 micrograms per dry standard cubic meter, or alternatively the application of a limestone wet scrubber with a liquid-to-gas ratio of 30 gallons per 1,000 actual cubic feet per minute of exhaust gas. The final rule also adopted a standard for new and existing sources banning the use of utility boiler fly ash in cement kilns where the fly ash mercury content has been increased through the use of activated carbon or any other sorbent unless the cement kiln seeking to use the fly ash can demonstrate that the use of fly ash will not result in an increase in mercury emissions over its baseline mercury emissions ( i.e., emissions not using the mercury-laden fly ash). EPA also issued a THC standard for new cement kilns (except for greenfield cement kilns that commenced construction on or before December 2, 2005) of 20 parts per million (corrected to 7 percent oxygen) or 98 percent reduction in THC emissions from uncontrolled levels. EPA did not set a standard for HCl, determining that HCl was a pollutant for which a threshold had been established, and that no cement kiln, even under conservative operating conditions and exposure assumptions, would emit HCl at levels that would exceed that threshold level, allowing for an ample margin of safety. EPA pointed to CAA section 112(d)(4) authority as its rationale for not establishing HCl emissions limits. D. Reconsideration of EPA Final Action in Response to the Remand At the same time we issued the final amendments, EPA on its own initiative made a determination to reconsider the new source standard for mercury, the existing and new source standard banning cement kiln use of certain mercury-containing fly ash, and the new source standard for THC (71 FR 76553, December 20, 2006). EPA granted reconsideration of the new source mercury standard both due to substantive issues relating to the performance of wet scrubbers and because information about their performance in the industry had not been available for public comment at the time of proposal; that information is now available in the docket. We also committed to undertake a test program for mercury emissions from cement kilns equipped with wet scrubbers that would enable us to resolve these issues. We further explained that we were granting reconsideration of the work practice requirement banning the use of certain mercury-containing fly ash in cement kilns to allow further opportunity for comment on both the standard and the underlying rationale and because we did not feel we had the level of analysis we would like to have to support a beyond-the-floor determination. We granted reconsideration of the new source standard for THC because the information on which the standard was based arose after the period for public comment. We requested comment on the actual standard, whether the standard is appropriate for reconstructed new sources (if any should occur) and the information on which the standard is based. We specifically solicited data on THC emission levels from preheater/precalciner cement kilns. We stated that we would evaluate all data and comments received, and determine whether in light of those data and comments it was appropriate to amend the promulgated standards. EPA received comments on the notice of reconsideration from two cement companies, three energy companies, three industry associations, a technical consultant, one State, one environmental group, one ash management company, one fuels company, and one private citizen. As part of these comments, one industry trade association submitted a petition to withdraw the new source MACT standards for mercury and THC and one environmental group submitted a petition for reconsideration of the 2006 final action. A summary of these comments is available in the docket for this rulemaking. 7 7 Summary of Comments on December 20, 2006 Final Rule and Notice of Reconsideration. April 15, 2009. In addition to the reconsideration discussed above, EPA received a petition from Sierra Club requesting reconsideration of the existing source standards for THC, mercury, and HCl, and judicial petitions for review challenging the final amendments. EPA granted the reconsideration petition. The judicial petitions have been combined and are being held in abeyance pending the results of the reconsideration. In March 2007 the DC Circuit Court issued an opinion ( Sierra Club v. EPA, 479 F.3d 875 (DC Cir. 2007) ( Brick MACT )) vacating and remanding CAA section 112(d) MACT standards for the Brick and Structural Clay Ceramics source categories. Some key holdings in that case were: • Floors for existing sources must reflect the average emission limitation achieved by the best performing 12 percent of existing sources, not levels EPA considers to be achievable by all sources (479 F. 3d at 880-81); • EPA cannot set floors of “no control.” The Court reiterated its prior holdings, including National Lime Ass'n, confirming that EPA must set floor standards for all HAP emitted by the major source, including those HAP that are not controlled by at-the-stack control devices (479 F. 3d at 883); and • EPA cannot ignore non-technology factors that reduce HAP emissions, including when determining which sources are best performers for purposes of ascertaining the MACT floor. Specifically, the Court held that “EPA's decision to base floors exclusively on technology even though non-technology factors affect emissions violates the Act.” (479 F. 3d at 883). Based on the statute, as interpreted in the Brick MACT decision, we believe a source's performance resulting from the presence or absence of HAP in raw materials must be accounted for in establishing floors; i.e., a low emitter due to low HAP proprietary raw materials can still be a best performer. In addition, the fact that a specific level of performance is not being intentionally achieved by the source is not a legal basis for excluding the source's performance from consideration. Sierra Club v. EPA, 479 F.3d at 631-34; National Lime Ass'n, 233 F. 3d at 640. The Brick MACT decision also reiterated that EPA may account for variability in setting floors. However, the Court found that EPA erred in assessing variability because it relied on data from the worst performers to estimate best performers' variability, and held that “EPA may not use emission levels of the worst performers to estimate variability of the best performers without a demonstrated relationship between the two.” 479 F. 3d at 882. After considering the implications of this decision, EPA granted the petition for reconsideration of all the existing source standards in the 2006 rulemaking. A second Court opinion of relevance to the Portland cement NESHAP amended here is Sierra Club v. EPA, 551 F. 3d 1019 (DC Cir. 2008). In that case, the court vacated the regulations contained in the General Provisions which exempt major sources from CAA section 112(d) standards during periods of startup, shutdown and malfunction (SSM). The regulations (in 40 CFR 63.6(f)(1) and 63.6(h)(1)) provided that sources need not comply with the relevant CAA section 112(d) standard during SSM events and instead must “minimize emissions * * * to the greatest extent which is consistent with safety and good air pollution control practices.” The current Portland Cement NESHAP references the now-vacated rules in the General Provisions. As a result of the court's decision, we are removing the references to the vacated provisions and addressing SSM in this rulemaking. Discussion of this issue may be found in Section IV.A. III. Background Information on the NSPS 40 CFR Part 60, Subpart F NSPS implement CAA section 111(b) and are issued for categories of sources which cause, or contribute significantly to, air pollution which may reasonably be anticipated to endanger public health or welfare. The primary purpose of the NSPS is to attain and maintain ambient air quality by ensuring that the best demonstrated emission control technologies are installed as the industrial infrastructure is modernized. Since 1970, the NSPS have been successful in achieving long-term emissions reductions in numerous industries by assuring cost-effective controls are installed on new, reconstructed, or modified sources. Section 111 of the CAA requires that NSPS reflect the application of the best system of emission reductions which, taking into consideration the cost of achieving such emission reductions, any non-air quality health and environmental impact and energy requirements, the Administrator determines has been adequately demonstrated. This level of control is commonly referred to as best demonstrated technology (BDT). EPA promulgated Standards of Performance for Portland Cement Plants (40 CFR, part 61 subpart F) in 1971 ((36 FR 24876, December 23, 1971). Section 111(b)(1)(B) of the CAA requires EPA to periodically review and revise the standards of performance, as necessary, to reflect improvements in methods for reducing emissions. We have conducted three reviews of the standards (39 FR 20793, June 14, 1974; 39 FR 39874, November 12, 1974; and 53 FR 50354, December 14, 1988). We proposed the current review of the Portland Cement Plant NSPS on June 16, 2008. We received a total of 46 comments from the Portland cement industry, environmental groups, State environmental agencies and others during the comment period. This final rule reflects our consideration of all the comments we received. Detailed responses to the comments not included in this preamble are contained in the Summary of Public Comments and Responses document which is included in the docket for this rulemaking. IV. Summary of EPA's Final Action on the Amendments In this section we discuss the final amendments to 40 CFR part 63 subpart LLL and part 60 subpart F, the changes since proposal, and the rationale for the changes. Responses to specific comments may be found in the response to comment section of this document or in the response to comment documents contained in the dockets for this rulemaking. As a preliminary matter, EPA notes that certain portions of the existing rules are not being amended substantively but are being reprinted, sometimes with editorial changes, in today's regulatory text. As explained at proposal, EPA did so either for readers' convenience or to make certain non-substantive “plain English” changes to rule text. 74 FR at 21140. The final rule text makes these same non-substantive changes (which did not occasion public comment), and reprints certain existing provisions. Provisions from the existing rules which do not change substantively include the PM emission limits for kilns currently subject to the NSPS, the opacity limits for raw materials dryers, raw mills, and finish mills, and the limits for dioxin furan (D/F) for cement kilns. We reorganized the testing and monitoring requirements of both rules to make them more consistent, and modified the rule language to better conform with the June 1, 1998, Executive Memorandum on Plain Language in Government Writing. A. What are EPA's final actions on 40 CFR part 63, subpart LLL? 1. What are the final actions on emission limits under 40 CFR part 63, subpart LLL? In this action, we are amending the emission limits for mercury, THC, and PM from new and existing kilns located at a major or area source, and for HCl from new and existing kilns located at major sources. We identify these standards below for the emission sources in a typical Portland cement production process. We have applied the limits for existing and new sources in this final rule for mercury and THC to area sources consistent with CAA section 112(c)(6). As noted above, mercury is one of the pollutants specifically singled out by Congress in CAA section 112(c)(6), and THC is a surrogate for POM and PCB, which are also section 112(c)(6) HAP. See 63 FR 14193, March 24, 1998 (determination to control all THC emissions from the source category under MACT standards). Finally, Portland cement kilns are a listed area source category for urban HAP metals pursuant to CAA section 112(c)(3), and control of these metal HAP emissions (via the standard for the PM non-mercury HAP metal surrogate) is required to ensure that area sources representing 90 percent of the area source emissions of urban metal HAP are subject to CAA section 112 control, as required by CAA section 112(c)(3). The PM standards for area sources reflect MACT, as explained below. a. Changes to Overall Floor Setting Procedure The MACT floor limits for each of the HAP and HAP surrogates (mercury, THC, HCl, and PM) are calculated based on the performance of the lowest emitting (considered best performing in this rulemaking) sources in each of the MACT floor pools for each HAP or HAP surrogate. We ranked all of the sources for which we had data based on their emissions and identified the lowest emitting 12 percent of the sources for which we had data, which ranged from two kilns for THC to 11 kilns for mercury for existing sources. For new source MACT, the floor was based on the best controlled source. In assessing sources' performance, EPA may consider variability both in identifying which performers are “best” and in assessing their level of performance. Brick MACT, 479 F. 3d at 881-82; see also Mossville Envt'l Action Now v. EPA, 370 F.3d 1232, 1241-42 (DC Cir 2004) (EPA must exercise its judgment, based on an evaluation of the relevant factors and available data, to determine the level of emissions control that has been achieved by the best performing sources considering these sources' variability). Variability in cement kilns' performance has a number of causes. For many of the pollutants, notably mercury and THC, most kilns do not have add-on control devices. The main source of variability for these pollutants consequently is the differing mercury and organic concentrations in the raw materials and fuels which are fed to the kiln. For particulate matter, which is well-controlled by baghouses, the variability is chiefly due to variations in performance of the control device for which both run-to-run and test-to-test variability must be accounted. 8 8 Run-to-run variability is essentially within-test variability, and encompasses variability in individual runs comprising the compliance test, and includes uncertainties in correlation of monitoring parameters and emissions, and imprecision of stack test methods and laboratory analysis. 72 FR at 54877 (Sept. 27, 2007). Test-to-test variability results from variability in pollution device control efficiencies over time (depending on many factors, including for fabric filters the point in the maintenance cycle in which a fabric filter is tested). Test-to-test variability can be termed long-term variability. 72 FR at 54878. In determining the MACT floor limits, we first determine the floor, which, as explained above, for existing sources is the level achieved in practice by the average of the top 12 percent of existing sources, or the level achieved in practice by the best controlled similar source for new sources. In this rule, EPA is using lowest emissions as the measure of best performance. We then assess variability of the best performers by using a statistical formula designed to estimate a MACT floor level that is equivalent to the average of the best performing sources based on future compliance tests (or calculated inputs in the case of mercury). Specifically, the MACT floor limit is an upper prediction limit (UPL) calculated with the Student's t-test using the TINV function in Microsoft Excel ® . The Student's t-test has also been used in other EPA rulemakings ( e.g., NSPS for Hospital/Medical/Infectious Waste Incinerators, NESHAP for Industrial, Commercial, and Institutional Boilers and Process Heaters) in accounting for variability. A prediction interval for a future observation is an interval that will, with a specified degree of confidence, contain the next (or some other pre-specified) randomly selected observation from a population. In other words, the prediction interval estimates what the upper bound of future values will be, based upon present or past background samples taken. The UPL consequently represents the value which we can expect the mean of future observations (3-run average for HCl, 30-day average for mercury, PM, HCl (sources not having wet scrubbers or otherwise electing CEM-based compliance), and THC) to fall below within a specified level of confidence, based upon the results of an independent sample from the same population. In other words, if we were to randomly select a future test condition from any of these sources ( i.e., average of 3 runs or 30-day average) we can be 99 percent confident that the reported level will fall at or below the UPL value. Use of the UPL is appropriate in this rulemaking because it sets a limit any single or future source can meet based on the performance of members of the MACT pool. This formula uses a pooled variance (in the s 2 term) that encompasses all the data-point to data-point variability of the best performing sources comprising the MACT floor pool for each HAP. Where variability was calculated using the UPL statistical approach ( i.e., for the Hg, HCl, and PM standards), we used the average (or sample mean) and sample standard deviation, which are two statistical measures calculated from the data distributions for mercury, HCl, and PM. The average is a central value of a data set, and the standard deviation is the common measure of the dispersion of the data set around the average. We describe in detail in the preamble sections on mercury, HCl and PM and in the memorandum “Development of the MACT Floors for the Final NESHAP for Portland Cement”, August 6, 2010” how these averages were developed. We note here that the methodology accounts for both short-term and long-term variability and encompasses run-to-run and test-to-test variability. The formula also applies differently depending on how the underlying data set is distributed. To this end, EPA carefully evaluated the data sets for each HAP to ascertain whether the data were normally distributed, or distributed in some other manner ( i.e., log normally). After applying standard and rigorous statistical tests (involving the degree of “skewness” of the data), we determined that the distributions for mercury and particulate matter were approximately a normal distribution, which in turn determined the final form of the UPL equation. See Floor Calculations for Final Portland Cement NESHAP, August 6, 2010; see also 75 FR at 32019-20. EPA was able to reasonably calculate variability for the THC and HCl standards without needing to use predictive statistics. Specifically, the data set for THC contains a sufficient number of observations to estimate the variability without the need of any type of statistical intervals (no UPL needed to be calculated). For HCl, although EPA applied the UPL formula in developing the HCl standard, the key issue for the HCl data set is the HCl analytic method's detection limit, which ultimately dictated the level of the standard. At proposal we adopted a form of the UPL equation that has been used in a previous rulemaking. 69 FR 21233 April 20, 2004. Commenters stated correctly that there was an error in the equation used at proposal. As a result of these comments, EPA corrected the formula in the final rule. The UPL used in the final rule is calculated by: ER09SE10.000 Where: x = the mean of the sample data set n = the number of test runs m = the number of test runs in the compliance average s 2 = observed variance t = student t distribution statistic This calculation was performed using the following Excel functions: Normal distribution: 99 percent UPL = AVERAGE(Test Runs in Top 12percent) + [STDEV(Test Runs in Top 12percent) x TINV(2 x probability, n-1 degrees of freedom)*SQRT((1/n)+(1/m))], for a one-tailed t-value, probability of 0.01, and sample size of n This is the same UPL equation that EPA used in more recent rulemakings. See 75 FR 32020 (June 4, 2010) and 75 FR 31905 (June 4, 2010). The value of “m” denotes the number of future observations, and it is used to calculate an estimate of the variance of the average of m-future observations. For example, if 30-day averages are used to determine compliance (m=30), the amount of variability in the 30-day average is much lower than the variability of the daily measurements in the data base, which results in a lower UPL for the 30-day average. As an illustration of the effects that correcting the UPL had on the emission limits, we calculated the UPLs for mercury and PM using the proposal version of the UPL formula, and the version used in this final rule. The results of these calculations are presented in Table 1. Both calculated limits are about 20 percent lower when the corrected UPL formula is used. Table 1—Comparison Emission Limits Calculated Using Proposal UPL Formula Versus Corrected UPL Formula for Existing Sources Proposal (uncorrected UPL formula) Proposal (corrected UPL formula) Mercury, (lb/MM tons feed) [lb/MM tons clinker] 29.6 [48.8] 22.5 [37.1] PM (lb/ton clinker) 0.05 0.04 b. Ramifications of EPA Statistical Approach A number of commenters maintained that this final rule raises the (perceived) quandry voiced by Judge Williams in his concurring opinion in Brick MACT where an achieved level of performance for purposes of CAA section 112(d)(3) results in a standard which is unachievable under CAA section 112(d)(2) because it is too costly or not cost-effective. Brick MACT, 479 F. 3d at 884-85. EPA is of course mindful of the repeated admonitions (with accompanying vacaturs and remands) from the DC Circuit that MACT floors must reflect achieved performance, that HAP content of process inputs (raw materials and fuels) must be accounted for in ascertaining sources' performance, and that costs cannot be considered by EPA in ascertaining the level of the MACT floor. See, e.g., Brick MACT, 479 F. 3d at 880-81, 882-83; NRDC v. EPA, 489 F. 3d 1364, 1376 (DC Cir. 2007) (“Plywood MACT”); see also Cement Kiln Recycling Coalition v. EPA, 255 F. 3d 855, 861-62 (DC Cir. 2001) (“achievability” requirement of CAA section 112(d)(2) cannot override the requirement that floors be calculated on the basis of what best performers actually achieved). EPA is also mindful of the need to account for sources' variability (both due to control device performance and variability in inputs) in assessing sources' performance when developing technology-based standards. See, e.g., Mossville Environmental Action Now v. EPA, 370 F. 3d 1232, 1242 (DC Cir. 2004); National Lime I, 627 F. 2d 416,433-34(DC Cir. 1980). EPA has carefully developed data for each standard, assessing both technological controls and HAP inputs in doing so. For mercury, EPA used the pooled variance from all of the best performing kilns in the MACT floor pool in order to fully assess these kilns' intra-quarry and other variable mercury levels. EPA also used pooled variance to assess the variability of HCl and PM emissions for the MACT floor pool kilns. See 70 FR at 59438 (Oct. 12, 2005) (explaining when use of such pooled variances can be reasonable). EPA has also adopted 30-day averaging periods for all of the standards, further allowing short term fluctuations to be averaged out over the 30-day period. The result are floors which reasonably estimate the performance over time of the best performing sources, as do the standards based on those floors. It is true that many sources will need to install controls to meet these standards, and that these controls have significant costs (although EPA estimates that the rule's costs are substantially outweighed by its benefits). See Section VI below. This is part of the expected MACT process where, by definition, the averaged performance of the very best performers sets the minimum level of the standard. The Agency believes that it has followed the statute and applicable case law in developing its floor methodology. Industry commenters nonetheless maintained that EPA had not properly accounted for variability of the best performing sources because not even these sources can meet the standards which are predicated on their own performance without adding controls. This contention lacks a basis in the record. For mercury, all performers in the MACT floor pool—not just those with emissions below the average of the best performers— meet the promulgated standard (highest 30-day average in MACT pool is 41.63 lb/MM tons clinker; the standard is 55 lb/MM tons clinker (30-day average). In addition, several additional kilns, which are not in the pool of best performers, meet the standards. For THC, all kilns in the pool of best performers meet the promulgated standard (highest 30-day average in MACT pool is 5.68 ppmv; the standard is 24 ppmv). In addition, seven additional kilns which are not in the pool of best performers meet the standards. Indeed, nine of the 11 kilns for which EPA has CEM data are meeting the promulgated standards for THC. For PM, all six kilns in the MACT pool as well as twelve kilns overall meet the promulgated 30-day standard even though the measurements in the data base are stack tests ( i.e., unlike for mercury and THC, these are not averaged values). 9 Virtually all kilns in the MACT floor pool are meeting the HCl standard, although this is largely the result of setting the standard at a level reflecting analytic method quantitation limits. 9 Development of The MACT Floors For The Final NESHAP For Portland Cement. August 6, 2010. Commenters presented virtually no quantified data that floor plants are unable to meet the standards. See National Association of Metal Finishers v. EPA, 719 F. 2d 624, 649 (3d Cir. 1983) (unquantified assertions are entitled to little if any weight). Rather, their comments (comment 2845 at Table 1, echoed by many other industry commenters) provided narrative descriptions purporting to demonstrate that floor plants would not be able to achieve the standards. 10 In those instances where commenters provided actual data on these plants' performance, EPA took the information into account in developing the final standards. Indeed, EPA adjusted all of the standards based on actual data presented. However, EPA is not willing to act on pure supposition and conjecture regarding variability, particularly in the face of record information indicating that not only all floor plants but a number of additional plants are already meeting the promulgated standards. 10 For example, the commenter asserted, without providing support, that for the floor kilns the standards were “achieved in practice, but not under foreseeable operations”; “achieved in practice based on limited stack tests”; “data shows that proposed standard was not achieved in practice when malfunction emission [sic] are included in compliance determination” (although no such data were provided to EPA). c. Mercury Limits for Kilns i. Floor Determination. We proposed mercury emissions limits of 43 lb/million (MM) tons clinker for existing sources and 14 lb/MM tons clinker for new sources. The proposed floor was based on 30 days of data on all kiln inputs for 89 kilns. See 74 FR at 21142-43. For all kilns but the five equipped with wet scrubbers, emissions were assumed to equal the total mass of mercury fed to each kiln. Scrubber-equipped kilns were considered to emit all mercury minus an assumed amount representing the average performance of the wet scrubbers. For kilns that waste cement kiln dust (CKD), the mercury component of the CKD was subtracted from inputs to calculate emissions. Id. By conducting a total mass balance for mercury and then assuming that all mercury inputted is emitted (minus conservatively estimated removals for scrubber usage and dust wastage), EPA made a near worst case assumption as to kilns' mercury emission levels. The kilns were then ranked from best to worst based on the extrapolated mercury emissions, normalized to clinker production. EPA further proposed that no beyond the floor standard was appropriate for either existing or new sources. Id. at 21149. Since proposal we received updated data on certain kilns' raw materials usage and mercury content 11 and used that data to revise our average mercury emissions estimates from the best performing kilns at proposal. 12 We have also revised upward the floor kilns' projected emissions based on their reasonably estimated intra-quarry variability (explained further below). As a result, estimated emissions from these kilns increased, and one of the kilns in the group of sources used to set the existing source floor is no longer one of the best performing kilns. At proposal, the average mercury emissions of the top 12 percent of the kilns was 27.4 pounds per million (lb/MM) tons clinker, and the average emissions of the best performing source were 13.4 lb/MM ton clinker. After revising our mercury emissions estimates, the averages were 32 and 14 lb/MM tons clinker, respectively, as shown in Table 2. 11 See Portland Cement Association Comments on the NESHAP-Proposed Rule (Docket Number: EPA-HQ-OAR-2002-0051) (September 4, 2009) at pp. 31-35. 12 Development of The MACT Floors For The Final NESHAP For Portland Cement, August 6, 2010. Table 2—Mercury MACT Floor Kiln code Mercury emissions (lb/MM ton feed) 1589 8.48 1650 9.53 1315 15.26 1302 15.28 1248 16.63 1259 21.33 1286 22.65 1594 25.23 1435 25.51 1484 25.51 1364 25.91 MACT—Existing Kilns Average: lb/MM tons feed (lb/MM tons clinker) 19.21 (31.7) Total variance 272.3 UPL: lb/MM tons feed (lb/MM tons clinker) 32.8 (54.1) MACT—New Kilns Average: lb/MM tons feed (lb/MM tons clinker) 8.48 (14.0) Total variance 35.2 UPL: lb/MM tons feed (lb/MM tons clinker) 12.3 (20.3) As noted above, we are taking into account operating variability of the best performing kilns, or in the case of new source MACT the single best controlled kiln, in assessing their performance ( i.e., both in determining which performers are best, and calculating what their performance is). When we calculated the UPL with 99 percent confidence for the best performing sources (or in the case of new source MACT the best controlled single source), we calculated a mercury floor of 55 lb/MM tons clinker for existing sources and 21 lb/MM tons clinker for new sources. We chose a 30-day averaging period for the mercury emission limit. As noted above, the use of a 30-day average (as opposed to hourly or daily averages) tends to reduce variability, and also best reflects the nature of the data from which the floor was derived and assures that several operating cycles of raw mill on and off are included in each average. Id. at 21144. Industry commenters stated that we should account for additional sources of variability in this floor determination, namely intra-quarry variability and variability of the mercury content in local coals which kilns could utilize. As explained below, beyond those situations where commenters documented that sources actually used inputs with greater mercury content than used during the 30-day test period ( see note 11 above), or where further intra-quarry mercury variability could reasonably be estimated, we did not do so. EPA is of course aware that limestone quarries are immense, and are customarily used from periods of 50 to 100 years. Taking the average of 30 days of sampling data from one part of the quarry would not necessarily encompass all of the different mercury levels throughout the quarry. Although industry commenters originally raised the issue of long term intra-quarry variability during the initial May 2007 30-day data collection, no plant chose to perform additional sampling and analysis of their raw materials and feed that would have allowed this issue to be directly addressed. Certain industry commenters did point, however, to data from the 30-day sampling effort as providing useful information on potential intra-quarry mercury variability of the two best performers. The data come from 30-day sampling conducted at four sources (three of which are located at a single facility), which all quarry limestone from a common geologic limestone formation. 13 All six kilns (the two floor kilns, and the other four kilns in the immediate vicinity) are in the same city and within 9 miles of each other. It is a reasonable assumption that variability of mercury levels (as opposed to mercury levels themselves) across this formation are substantially the same and therefore that the variability of mercury levels in the two best performers' quarries can be adjusted to reflect the variability seen in the other quarries which are part of the common geologic formation. See Brick MACT, 479 F. 3d at 881-882 (EPA may look at performance of sources which are not among the best in estimating variability of best performers if there is a demonstrated relationship between the two). 13 Memorandum. Intra-quarry Variability Estimate, July 21, 2010. EPA further applied these estimates of intra-quarry variability to the mercury data for the other best performing kilns ( i.e., applied the same RSD to the other best performing sources). EPA did so to more robustly characterize long-term variability of these sources' quarries' mercury levels. The fact that intra-quarry variability of the two lowest emitting sources increased somewhat after examination with other quarries in the common geologic formation confirms that there can be further variability. Since the intra-quarry variability comes from quarries servicing the two lowest emitting kilns, EPA would not expect intra-quarry variability to be lower for the other best performing sources. In no other instance did commenters provide data that we could use to determine intra-quarry variability for kilns in the MACT floor pool. 14 14 For example, one industry commenter submitted core (unground, unprocessed) samples from its quarry which samples differed in mercury content by approximately one order of magnitude. This facility is not a best performer, the samples are single measurements (rather than 30-day measurements or some longer duration), and (unlike the 30-day measurements used as the basis for the standard) have not been processed ( i.e., passed through the quarry crushers and mixed in the storage pile which would tend to make the material more homogeneous). Therefore, these data are not comparable to the data used to set the MACT floors. Commenters also maintained that because cement kilns can burn different types of coal, variability of coal mercury content needs to be factored into estimates of sources' performance. Commenters maintained that they obtained coal from a “local market” and so might eventually use any coal from that market. The comments did not further link coal to individual mines or to other particularized sources. Commenters appear to be asking for an upward adjustment of the MACT floors based on coal they might potentially use but never had used. EPA believes that allowing for any inputs that might conceivably be used in the future, including from sources in an area which a source has never used to date, goes beyond a reasonable estimate of performance over time and invites inflated estimates of variability based only on hypothesized possibilities, not on actual behavior. 15 EPA not only does not believe such methodology is a reasonable means of calculating sources' achieved performance, but also believes that such an approach creates a perverse incentive to build in compliance margins based on seeking out more polluted inputs. 15 The situation differs from use of limestone from a proprietary quarry. Not only have sources used the quarry in the past but will necessarily continue to do so in the future. For example, the price of lower mercury coal may increase as a result of this rule (it may be more desirable as a means of keeping mercury emissions low), so plants may seek out higher mercury coal which they otherwise have never used. This type of volitional activity does not seem to be within the ambit of normal variability of process inputs. In addition, facilities do have choices for coal. As noted in the comments, some facilities obtain coals from several States, while others appear to limit themselves to more local areas. However, coal is a commodity that can be transported long distances to fuel utility boilers. Therefore, we believe that a facility should have sufficient coals available that they would not be compelled to use a higher mercury coal just because it happens to be near the plant. ii. Decision Regarding Whether To Create a Subcategory Based on Limestone Mercury Content EPA may create subcategories which distinguish among “classes, types, and sizes of sources.” CAA section 112(d)(1). EPA reads this provision to provide the Agency with discretion to subcategorize, and EPA may exercise that discretion if sources are rationally distinguishable due to some difference in class, type or size. See Lignite Energy Council v. EPA, 198 F. 3d 930, 933 (DC Cir. 1999) (“EPA is not required by law to subcategorize—section 111[b][2] merely states that `the Administrator may distinguish among classes, types, and sizes within categories of new sources' ” (emphasis original)). Moreover, as we noted at proposal, “normally, any basis for subcategorizing must be related to an effect on emissions, rather than to some difference among sources which does not affect emissions performance.” 74 FR at 21145. EPA may also exercise this discretion on a pollutant-specific basis, since the difference in class, type or size may only have practical significance for certain HAP. In this final rule, EPA carefully considered the possibility of creating different subcategories of cement kilns with respect to mercury emissions. The subcategorization possibilities for mercury which we considered and rejected at rule proposal were the type of kiln, presence of an inline raw mill, practice of wasting cement kiln dust, total mercury inputs, or geographic location. See 74 FR 21144-21145. We likewise reject these bases in this final rules for the reasons already stated. At proposal we also considered subcategorizing by the mercury concentration of the limestone in the kiln's proprietary quarry. We did not propose to create this type of subcategory, and also choose not to do so in this final rule. As we explained at proposal, the facts do not indicate sharp disparities in limestone mercury content that readily differentiate among types of sources for most of the facilities for which we have data, and thus do not support this subcategorization approach for the majority of the facilities. See Figure 1 showing a gradual continuum of mercury concentrations in limestone for all but two outlying plants. ER09SE10.001 Industry commenters who supported creating a separate subcategory for the two highest mercury emitting sources based on limestone mercury content agreed with this assessment. Thus, EPA sees no technical justification to subcategorize by limestone quarry mercury content for the majority of the source category. However, as also shown in Figure 1, there is a sharp disparity for two kilns which have the highest quarry mercury contents. These sources' mercury emissions are also disproportionately higher than all other cement kilns', and are related almost entirely to the limestone mercury content, not to mercury content of other inputs. Commenters who supported subcategorization by quarry mercury levels recommended that EPA create a separate source category for these two kilns based on their uniquely high quarry mercury contents. If we were to set a separate subcategory for these two kilns, we determined that the floor level of control would be approximately 2100 lb/MM tons clinker. Due to the high level of this floor, we evaluated a beyond-the-floor option of 85 percent reduction in emission for the highest emitting kiln. This level would represent the highest level of mercury control believed achievable for the highest emitting facility based on test data on a pilot mercury control system for that facility. 16 This level of control would result in an emissions limit of approximately 500 lb/MM tons clinker. This level is over 10 times the level that will be required for all other kilns, and even exceeds every other kiln's uncontrolled mercury emissions levels which range from 20 to 400 lb/MM tons clinker. 16 Letter, C. Lesslie, Ash Grove Cement to P. Tsirigotis, U.S. EPA, April 22, 2010. Mercury in the air eventually settles into water or onto land where it can be washed into water. Once deposited, certain microorganisms can change it into methylmercury, a highly toxic form that builds up in fish, shellfish and animals that eat fish. Fish and shellfish are the main sources of methylmercury exposure to humans. Methylmercury builds up more in some types of fish and shellfish than in others. The levels of methylmercury in fish and shellfish depend on what they eat, how long they live and how high they are in the food chain. Mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages. Research shows that most people's fish consumption does not cause a health concern. However, it has been demonstrated that high levels of methylmercury in the bloodstream of unborn babies and young children may harm the developing nervous system, making the child less able to think and learn. 17 Heightened concern for mercury's toxic effects is reflected directly in the structure of section 112 of the Act. Mercury is one of the pollutants identified for MACT-level control under the CAA's air toxics provision even (in most instances) when emitted by area sources ( see CAA section 112(c)(6)). 17 For more information see http://www.epa.gov/mercury/about.htm. Thus, creating a high-mercury subcategory for two kilns based on limestone mercury content would result in standards allowing emissions of 500 lb/MM tons of clinker. Based on 2008 production rates, this would allow 1,020 pounds of mercury emissions per year from the potential two-plant subcategory. To put this in perspective, the rest of the industry (92 plants) would be allowed to emit 1,012 pounds tons of mercury per year (again based on 2008 production rates), and the two high-emitting plants would be allowed to emit 1,020 pounds per year. This would result in a doubling of mercury emissions from this source category after the application of MACT. Moreover, national mercury emissions for industrial sources are approximately 50 tpy. 18 That would mean that these two sources alone would constitute 1 percent of the industrial mercury emissions for the U.S. EPA believes it is a reasonable exercise of discretion not to create a subcategory, where, as here, doing so would allow on-going emissions of a disproportionately high volume of a high-toxicity pollutant. 18 Mercury Emission in the U.S. by Source Category 1990 to 1993, 2002, and 2005. http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewMidImg&ch=46&lShowInd=0&subtop=341&lv=list.listByChapter&r=188199. Due to mercury's high toxicity and the extremely high mercury emissions that would result, the Administrator is thus not exercising her discretion to subcategorize in setting the final mercury emissions limit. In light of this decision, it is unnecessary for EPA to address the further question of whether subcategorizing by raw material content of proprietary quarries is permissible under section 112 of the Act. Although the Agency has concluded that it is reasonable to set the same mercury standard for all cement kilns, we acknowledge the unique challenges that the highest emitting sources may face in meeting the reductions within the regulatory compliance timeline. In particular, as discussed at length above, the two highest emitting kilns—the kilns located in Durkee and Tehachapi—have unusually high levels of mercury in their proprietary limestone quarries, which, as typifies this sector, are located proximate to kiln operations. The mercury content of source material is the key factor in the high levels of emissions experienced at these kilns and a complicating consideration in their ability to achieve compliance in a timely manner. We also recognize that this challenge presents a unique opportunity to achieve substantial reductions in this naturally occurring, persistent, and widespread contaminant in an amount and on a schedule that exceeds what will be required in the final rule. The Agency believes that the two sources in question may be able in the near term to install aggressive controls, including activated carbon injection, that would result in dramatic near term reductions in mercury emissions (as much as 90 percent or two tons of mercury emissions in the first two years of operation). If they were to do so, these sources would emit substantially less mercury in the next few years than the alternative of allowing these facilities to continue to emit at current levels for three additional years, as would otherwise be the case. This would be a very substantial reduction in emissions of this pollutant. Annual emissions of mercury from all sources (not just cement kilns) are estimated to be 50 tpy, 19 and emissions from the entire source category are approximately 7.5 tons per year, 20 so that a two ton reduction is a substantial reduction of mercury emissions. 19 Mercury Emission in the U.S. by Source Category 1990 to 1993, 2002, and 2005. http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewMidImg&ch=46&lShowInd=0&subtop=341&lv=list.listByChapter&r=188199. 20 Summary of Environmental And Cost Impacts For Final Portland Cement NESHAP And NSPS August 6, 2010. We understand that one of the two high emitting kilns has already installed activated carbon injection, but that its performance could be further optimized. See 74 FR 21148. The other kiln would have to install activated carbon injection and both kilns would need to install dust shuttling. The net benefit to the environment and public health would extend a number of years beyond the MACT compliance deadline. If the Durkee and Tehachapi kilns were willing to make a near term reduction ( e.g., 90 percent) in their mercury emissions significantly before the compliance date in the rule, the Agency would consider providing these kilns a compliance schedule that extends beyond the three to four years specified in this rule. The purpose of such an approach would be to provide a substantial net benefit to the environment; therefore ultimate compliance with the MACT standard would need to be by a date that ensures the long term emissions from these sources would be significantly lower than their emissions from meeting the standard on the schedule in the rule. Given the nature of mercury and the additional reductions that could be obtained, the Agency is interested in exploring this concept. Finally, EPA notes that the same early reduction opportunities for mercury do not appear to exist for the rest of the Portland cement industry. It typically takes on the order of three years to install activated carbon injection technology. One of the high mercury plants has recently completed installation of ACI and has just commenced full scale operation of the kiln with ACI installed. The other kiln faces fewer installation barriers than other kilns. This is because the company has tested carbon injection and dust shuttling on one of its other kilns, and is already using dust shuttling to reduce emissions at another kiln, and is therefore better positioned to rapidly install controls after one year. To our knowledge, these circumstances are not applicable to the rest of the Portland cement source category, and could not even be duplicated at all the other facilities owned by these companies due to limitations in infrastructure available to design and build these systems. iii. Beyond the Floor Determinations for Mercury We are basing the final mercury standard on the floor level of control. When we establish a beyond the floor standard we typically identify control techniques that have the ability to achieve an emissions limit more stringent than the MACT floor. Under these final amendments, most existing kilns would have to have installed both a wet scrubber and activated carbon injection (ACI) for control of mercury, HCl and THC. 21 To achieve further reductions in mercury beyond what can be achieved using wet scrubber and ACI in combination, the available options would include closing the kiln and relocating to a limestone quarry having lower mercury concentrations in the limestone, transporting low-mercury limestone in from long distances, switching other raw materials to lower the amount of limestone in the feed, wasting CKD, and installing additional add-on control devices. These options were discussed at proposal, and were rejected as either technically infeasible or not cost-effective. Consideration of non-air quality impacts and energy requirements do not change this conclusion. See 74 FR at 22249-50. We received no comments that would cause us to change that determination. 21 Summary of Environmental and Cost Impacts of Proposed Revisions to Portland Cement NESHAP (40 CFR Part 63, subpart LLL), April 15, 2009. We did receive one comment from an environmental group requesting EPA explore fuel switching as a beyond the floor option. However, EPA thoroughly explored fuel switching as a control option in the 2006 rulemaking and determined that there were problems with fuel availability and the costs were prohibitive. See 70 FR 72340. EPA is not presently aware of facts that would justify a different approach in this final rule. As a result of these analyses, we determined that, considering the technical feasibility and costs, there is no reasonable beyond the floor control option, and the final mercury emission limit is based on the MACT floor level of control. c. THC Limits for Kilns and Raw Material Dryers The limits for existing and new sources in this final rule apply to both area and major sources. As noted earlier, we have applied these limits to area sources consistent with CAA section 112(c)(6). i. Floor Determination. EPA proposed THC emissions limits of 7 and 6 parts per million by volume dry (ppmvd) for existing and new sources respectively for both cement kilns and raw material dryers. The existing source standard was based on the performance of the best performing 12 percent of cement kilns for which we had THC CEMS data. At proposal we requested comment on the issue of whether or not we should base the existing source floor on the best performing five kilns, rather than on the best performing 12 percent (two kilns). Industry commenters supported the use of the best five kilns stating that this would be in keeping with what appeared to be the intent of Congress that five kilns should be the minimum number of sources on which to set an existing source floor. However, other commenters noted that a plain reading of the statute is that when the source category has 30 or more sources, the top performing 12 percent for which the Administrator has data must be used, even if this results in less than five facilities due to lack of available data. In this final rule we are reaffirming our decision at proposal to use the best performing 12 percent rather that the best performing five facilities because we believe this result to be unavoidably compelled by the literal language of the statute. At proposal we set the emissions limit based on the 99th percentile of the available data. As a result of new data received after the comment period, we recalculated the averages of the kilns for which we had CEMS data and selected the best performing two kilns (12 percent of 15 total kilns) based on their average emissions. See Calculations of Floors for Final Portland Cement NESHAP dated August 6, 2010. Because these were large data sets (688 and 274 readings), we directly calculated the 99th percentile of the 30-day averages to determine the MACT floor which is 24 ppmvd. 22 This is shown in Table 3. 22 In other words, as noted above, EPA possesses sufficient THC data that it is not necessary to estimate variability by use of the UPL equation. Rather, variability is calculated directly from the THC data set comprised of the two lowest emitting sources. ER09SE10.002 For new sources, we analyzed the data from the kiln with the lower numeric average to determine the 99th percentile of its performance. The result of this analysis was also a 24 ppmvd standard because this kiln had more variability (although a lower average performance) than the other kiln in the data set. This emission limit is based on a concentration measured dry, corrected to 7 percent oxygen and a 30-day average measured using a CEM. ii. Additional THC data received too late to be considered in this rulemaking. In addition to the THC CEMS data just discussed, we received another set of THC CEMS data from the Portland Cement Association (PCA). These data were not submitted to EPA until mid-June 2010, virtually too late for any consideration, much less considered analysis. This set consisted of THC CEMS data collected over periods ranging from 31 to 90 days for additional kilns not in the data base discussed above, as well as additional data from some of the kilns already in our data base. These additional data increased the total number of kilns with THC CEMS data to 30 kilns. The PCA also provided a floor analysis on this data set and recommended THC emissions limits. The data set as presented by PCA is shown in Table 4. Table 4—Portland Cement Association: Determination of Size of Best Performing Pool for Proposed Sub-Categories for THC [Mid-June 2010 data submission] Sub category Estimated U.S. population Kilns for which data are available Procedure for selecting pool of best performing kilns Existing units Rule Pool size New units Major Non-Commingled Kilns > 30 17 Best 12% 3 Best 1. Major Commingled Kilns < 30 7 Best 5 5 Best 1. Area Kilns < 30 6 Work Practices Standard. In this analysis, the PCA proposed two subcategories: Kilns where the coal preparation mill exhaust is comingled with the kiln exhaust, and kilns where the coal preparation mill has a separate stack. The PCA maintains that subcategories are needed because emissions for the coal preparation mill (which are believed to be chiefly methane from the coal) will, all other things being equal, elevate the THC emissions of the kiln exhaust. See also 74 FR at 21152. The PCA recommended floors are shown in Tables 5 and 6 below: Table 5—Alternative MACT Floors for THC Major Non-Commingled Kilns Existing units (ppm) New units (ppm) 99th Percentile 30 11 99.9th Percentile 36 12 Table 6—Alternative MACT Floors for THC Major Commingled Kilns Existing units (ppm) New units (ppm) 99th Percentile 70 17 99.9th Percentile 80 20 However, the PCA MACT analysis suffers from one major deficiency because it excludes area sources from the MACT floor analysis, and assumes a work practice for these sources. As previously noted, THC emissions serve as surrogates for POM and PCB emissions. CAA section 112(c)(6) requires EPA to list, and to regulate under standards established pursuant to CAA section 112(d)(2) or (d)(4), categories of sources accounting for not less than 90 percent of emissions of these HAP standards established under CAA section 112(d)(2) must reflect the performance of MACT. Again, as explained above, EPA has long since determined that area source cement kilns' THC emissions must be controlled under CAA section 112 (d)(2) or (d)(4) in order to satisfy the 90 percent requirement. Therefore, these area sources should have been included in the MACT floor analysis. If this error in the floor analysis is corrected, the MACT floor for the kilns with comingled exhaust would be unchanged from the PCA analysis of 70 ppmvd for existing and 17 ppmvd for new (assuming the statistical calculations were done correctly). However, this estimate is premised on the assumption that there are less than 30 kilns in this subcategory (so that 5 sources would be used to establish the floor). That assumption is based on data provided in the PCA report that indicated, of the 87 kilns that provided data to PCA on their coal preparation stack configurations, 13 had comingled exhaust. If there are actually 30 or more kilns with this configuration, the MACT floor would have to be based on the best performing 12 percent of 8 kilns (the 7 major source comingled kilns plus one area source comingled kiln) which would be one kiln, Lehigh at Union Bridge. If one kiln is used for the existing source floor, the existing source MACT limit would be 17 ppmvd using the 99th percentile. The estimate of 26 versus 30 or more sources causes a high level of uncertainty in this analysis. For sources that do not comingle the exhaust, the floor would appear to be approximately 13 ppmvd when the area sources are included in the analysis. This is also lower than the floor calculated from the long term data set out above (and would result in a standard roughly 50 percent more stringent than that which EPA is adopting). The PCA analysis also recommended a separate subcategory for kilns with high limestone outgassing based on the information shown below: ER09SE10.003 The limestone outgassing factor is determined by heating a sample of the limestone from the kiln's proprietary quarry to determine the potential for THC emissions based on the amount and types of organic materials present. The premise here is basically the same as previously discussed for subcategorization by limestone mercury content when setting mercury emissions limits, because the kiln is tied to its limestone quarry. The subcategory proposed was for sources with THC outgassing ≥ 65 mg/kg. The recommended THC emissions limits for this subcategory were 170 and 62 ppmvd for new and existing sources respectively. This analysis, however, suffers from the same defect previously discussed in that for a subcategory with only three sources where we have data, the best performing 12 percent would be one kiln, so the actual limit for new and existing would be 62 ppmvd. We rejected this option because it suffers from the same defects as subcategorization by limestone mercury content. First, the choice of high versus low organics appears arbitrary. A level between 75 and 175 could just as easily have been chosen. The selection of 65 appears to be an attempt to move the high THC emitting facility into a subcategory with a high limit. Second, subcategorizing in this manner could result in situations where a few facilities would be allowed to emit at levels well above the remainder of the sources in this source category. Third, although the two kilns with the highest outgassing limestone appear to be outliers (similar to the two facilities with unusually high limestone mercury contents), we do not have data on a majority of the kilns (as we do with mercury) and it is possible that if we had more data, the two facilities that appear to be outliers would be part of a gradual continuum, which would mean the level we chose to separate high and low outgassing limestone would be mistaken. We also considered combining all the THC CEMS data (the more recent PCA data, data used at proposal, and data received during the comment period which would create a data set of 34 kilns). The results of this analysis was a floor (based on the 99th percentile of the data) of 24 ppmvd for existing sources (the same standard adopted in the final rule) and 3 ppmvd for new sources (more stringent than the new source standard in the final rule). Given the short time available to review the PCA data, the uncertainty concerning the actual size of one of the subcategories, the fact that these data would not in our view significantly change the levels of the standard for most kilns, and the concerns we have with subcategorization by limestone organic outgassing potential, we conclude that there is no compelling reason to change our floor determination based on this new information, which again was submitted only days before the final rule requirements had to be determined in order to meet the court ordered deadline for this rule. iii. Beyond the floor determination. At proposal we evaluated several practices and technologies that are available to cement kilns to control emissions of organic HAP at a level beyond the floor. 74 FR at 21152. These practices include raw materials substitution, ACI systems and limestone scrubber and regenerative thermal oxidizer (RTO). We rejected each of these alternatives based on technical limitations or poor cost- effectiveness. Consideration of non-air quality impacts and energy support this determination as well (RTOs in particular being associated with appreciable energy penalties). 74 FR at 21152. We received no comments that have caused us to change that proposed decision. Therefore, we are choosing the floor level of control for the final THC emissions limit. iv. Standards for THC. We are establishing the emissions limit for THC at the floor level of control. In addition, because the final existing source standard will be more stringent than the new source standard of 50 ppmvd for greenfield new sources contained in the 1999 final rule, we are also removing the 50 ppmvd standard for both kilns and raw material dryers. EPA proposed an alternative floor for non-dioxin organic HAP, based on measuring the organic HAP itself rather than the THC surrogate. This equivalent alternative limit would provide additional flexibility in determining compliance, and it would be appropriate for those cases in which methane and ethane comprise a disproportionately high amount of the organic compounds in the feed because these non-HAP compounds could be emitted and would be measured as THC. At proposal we determined that organic HAP averaged 24 percent of the THC. Since proposal we have reevaluated these data and recalculated an average organic HAP concentration of 35 percent. Based on this percentage, and the fact that the THC emission limit is now 24 ppmvd, we are promulgating an alternative organic HAP limit of 9 ppmvd, corrected to 7 percent oxygen (or 19 percent oxygen for raw material dryers), for new and existing sources. The specific organic compounds that will be measured to determine compliance with the alternative to the THC limit are benzene, toluene, styrene, xylene (ortho-, meta-, and para-), acetaldehyde, formaldehyde, and naphthalene. These were the organic HAP species that were measured along with THC in the cement kiln emissions tests that were reviewed. Nearly all of these organic HAP species also were identified in an earlier analysis of the organic HAP concentrations in THC in which the average concentration of organic HAP in THC was 35 percent. 23 23 Summary of Organic HAP Test Data. August 6, 2010. The alternative standard will be based on organic HAP average concentration of organic HAP in THC was 35 percent. 24 The alternative standard will be based on organic HAP emission testing and concurrent THC CEMS measurements that will establish a site specific THC limit that will demonstrate compliance with the total organic HAP limit. The site specific THC limit will be measured as a 30 day rolling average. 24 Ibid. iv. THC Emissions from Raw Material Dryers. As we noted at proposal, some plants may dry their raw materials in separate dryers prior to or during grinding. See 74 FR at 21153; see also 63 FR at 14204. This drying process can potentially lead to organic HAP and THC emissions in a manner analogous to the release of organic HAP and THC emissions from kilns when hot kiln gas contacts incoming feed materials. The methods available for reducing THC emissions (and organic HAP) is the same technology described for reducing THC emissions from kilns and in-line kiln/raw mills. Based on the similarity of the emissions source and controls, we proposed to set the THC emissions limit of materials dryers at the same levels as the kilns. Commenters noted that stand alone raw materials dryers have higher gas flows relative to the amounts of fuels burned. This results in higher oxygen concentrations, typically as high as 19 percent. They also noted that raw material dryers may have higher THC and lower HAP emissions because raw materials dryers operate at lower temperature than kilns (since the dryer only needs to operate at the temperature needed to remove free water), and that the residence times for dryers is considerably longer than for kilns. However, although we agree that the exhaust oxygen contents of raw material dryers may be higher than occurs with a cement kiln, there are reasons to believe that dryers actually emit less hydrocarbons than kilns. Operating at lower temperatures, we would expect any hydrocarbons that are emitted from dryers to be only those with the highest volatility, and therefore that the potential for emissions of organic HAP would be less for dryers than for kilns. However, the longer residence times could tend to increase emissions. Therefore, making any conclusions on the emission of dryers relative to kilns is difficult. We also note that we are allowing dryers to also use the alternative organic HAP emissions limit, so if the surmise that organic HAP emissions are low relative to the cement kilns is correct, this alternative should be very viable for these sources. In short, we received no data indicating that the same limit as for kilns was infeasible, or that would otherwise allow us to set a different THC emissions limit for raw materials dryers. Therefore, in these final amendments we are setting the THC emissions limit at the same level as the cement kiln's, which is 24 ppmvd measured as propane. However, because raw material dryers have high oxygen contents due to their inherent operation characteristics (and not due to the addition of dilution air), referencing the raw material dryer standard to 7 percent oxygen would actually result in a more stringent standard than for cement kilns. For example, given the typical oxygen contents of kiln exhaust (7 to 12 percent), a kiln just meeting the THC limit of 24 ppmvd would have an actual stack measurement of approximately 16 to 24 ppmvd. If the raw material dryer standard is referenced to the same oxygen level, they would have to meet a measured THC limit of approximately 3 ppmvd. For this reason, we are referencing the oxygen level of the standard for raw materials dryers to 19 percent oxygen, which is the typical oxygen level found in the exhaust of these devices. d. Hydrochloric Acid Emissions From Kilns In the proposed rule we based the proposed HCl emission limit for major sources on HCl data measured at 27 kilns using Method 321. The data in ppmvd corrected to 7 percent oxygen (O 2 ) were ranked by emissions level and the top 12 percent (4 kilns) lowest emitting kilns identified as best performing existing sources. The calculated MACT floors were 2 ppmvd and 0.1 ppmvd respectively. i. Floor Determination. Subsequent to proposal, we received comments that indicated we had inappropriately (albeit inadvertently) included certain natural area sources in the MACT floor analysis. We have removed those natural area sources from the floor analysis. In addition, many of the source tests were not actually EPA Method 321 tests; others lacked important quality assurance information. As a result, we issued letters under CAA section 114 authority requiring facilities that were major sources and that had previously submitted data to retest their facilities. We used this new data set to calculate a MACT floor. The data from the best performing three sources, as determined by average emissions during the test, are shown below in Table 7. Table 7—HCl MACT Floor Kiln HCl emissions (ppmvd at 7% O 2 ) 1 0.34 2 0.44 3 0.46 MACT—Existing Average (Top 3) 0.41 Variance 0.02 UPL 0.52 MACT—New Average 0.34 Variance 0.0 UPL 0.34 However, these measurements are very close to the detection limit for analytic method 321 actually calculated in the field for HCl—from 0.2 to 0.3 parts per million by volume (ppmv) as measured in the stack. 25 The expected measurement imprecision for an emissions value occurring at or near the method detection level is in fact about 40 to 50 percent. This large measure of analytic uncertainty decreases as measured values increase: Pollutant measurement imprecision decreases to a consistent relative 10 to 15 percent for values measured at a level about three times the method detection level. See American Society of Mechanical Engineers, Reference Method Accuracy and Precision (ReMAP): Phase 1, Precision of Manual Stack Emission Measurements, CRTD Vol. 60, February 2001. Thus, if the value equal to three times the representative method detection level were greater than the calculated floor emissions limit, we would conclude that the calculated floor emissions limit does not account entirely for measurement variability. 25 Memorandum. EPA Method 321 Detection Limits and Minimum Quantification Limit, July 26, 2010. That is the case here with HCl. The calculated standard (not accounting for the inherent analytical variability in the measurements) is 0.52 ppm ( see Table 7 above). In order to account for measurement variability, we multiplied the highest reported minimum detection level for the analytic method by a factor of three which results in a level of 0.9 ppmv. This represents the lowest level that can be reliably measured using this test method, and we therefore believe that it is the lowest level we can set as the MACT limit taking the appropriate measurement variability into account. Converting this level to a dry basis at 7 percent oxygen results in a floor of 3 ppmvd for both new and existing sources. As explained further below, we are using a CEM to measure this standard, and it is a 30-day average. ii. Beyond the Floor Determination. At proposal we examined the use of a packed bed scrubber, which was assumed to have a higher HCl removal efficiency than the spray tower limestone scrubbers typically used in this industry. Considering the high costs, high cost-effectiveness and small additional emissions reduction (and adverse cross-media impacts), we did not believe that a beyond-the-floor standard for HCl is justified. We received no comment that would change that decision. In addition, the current HCl floor limit is actually set at the lowest level we believe can be accurately quantified by the applicable test method. Therefore, a lower standard could not be reliably quantified. For these reasons we selected the floor level of control as MACT for HCl for major sources. iii. Compliance Mechanisms. As proposed, kilns equipped with wet scrubbers may demonstrate compliance by means of stack testing at intervals of 30 months, plus utilize continuous monitoring of specified parameters. All other kilns are required to use a CEMS, with compliance based on a 30-day rolling average. Although the underlying data were obtained via stack tests, rather than with continuous monitors, EPA believes that because the HCl standard is established at a level higher than all measured values (to account for the inability to reliably measure any lower standard) and measured based on 30-day averages, it provides an ample compliance margin. iv. Determination not to Establish a Risk-Based Standard for HCl. At proposal, EPA elected not to exercise its discretion under CAA section 112(d)(4) and proposed a major source standard for HCl based on MACT. The primary basis for not setting a health-based standard was that setting a MACT standard for HCl not only controlled HCl but also co-controlled other HAP (such as HF, Chlorine (Cl 2 ), and hydrogen cyanide (HCN)) and criteria pollutants yielding very substantial environmental benefits. However, we also requested comment on whether we had the legal authority to establish a standard for HCl, and, if so, whether we should exercise our discretion to do so. 74 FR at 21154. After considering comments, EPA has decided not to exercise its discretion to establish a risk-based standard for HCl under CAA section 112(d)(4), opting instead to promulgate a standard for HCl based on the performance of MACT in this final rule. This section discusses the basis for that decision. Setting technology-based MACT standards for HCl will result in significant reductions in emissions of other pollutants, most notably SO 2 , and would likely also result in additional reductions in emissions of mercury, along with condensable PM, ammonia, and semi-volatile compounds. The additional reductions of SO 2 alone attributable to the MACT standard for HCl are estimated to be 124,000 tons per year in the third year following promulgation of the proposed HCl standard. These are substantial reductions with substantial public health benefits. SO 2 emissions are associated with a variety of human health, ecosystem, and visibility effects. 75 FR at 35525-27 (June 22, 2010). Even more significantly, SO 2 is also a precursor to PM 2.5 . Reducing SO 2 emissions also reduces PM 2.5 formation, human exposure, and the incidence of PM 2.5 -related health effects, among them premature mortality and cardiovascular and respiratory morbidity. See detailed discussion of PM 2.5 health effects in the text at Table 13 below. For these rules the SO 2 reductions represent a large fraction of the total monetized benefits from reducing PM 2.5 , but it is not possible to isolate the portion if the total monetized benefits attributable to the emission reductions of SO 2 resulting from the application of HCl controls. The benefits models assume that all fine particles, regardless of their chemical composition, are equally potent in causing premature mortality because there is no clear scientific evidence that would support the development of differential effects estimates by particle type. We estimate the number of premature mortalities avoided each year due to the reductions in PM 2.5 exposure attributable to this standard to be in the thousands. RIA Table 6-3. We also estimate there to be over 2800 instances of annual cardiovascular and respiratory morbidity cases avoided, and hundreds of thousands of work loss days avoided. Id. The monetized benefits just from premature mortality avoided attributable to PM 2.5 reductions from this standard are estimated to be $7.4 billion to $18 billion at the three percent discount rate and $6.7 billion to $17 billion at a seven percent discount rate, nearly an order of magnitude higher than the rule's estimated social costs. See Table 13 below. Although MACT standards may directly regulate only HAPs and not criteria pollutants, Congress did recognize, in the legislative history to section 112(d)(4), that MACT standards would have the collateral benefit of controlling criteria pollutants as well and viewed this as an important benefit of the air toxics program. 26 The EPA believes these health and environmental benefits to be large and important and fully in keeping with the paramount goal of the Clean Air Act “to protect and enhance the quality of the Nation's air” (CAA section 101(b)(1)), and so is adopting MACT standards for HCl. 27 26 See S. Rep. No. 101-228, 101st Cong. 1st sess. at 172. EPA consequently does not accept the argument that it cannot consider reductions of criteria pollutants in determining whether to exercise its discretion to adopt a risk-based standard under section 112(d)(4). There appears to be no valid reason that EPA must ignore controls which further the health and environmental outcomes at which section 112(d) of the Act is fundamentally aimed. 27 We further note that HCl is not the only acid gas HAP emitted by Portland cement plants. Hydrogen fluoride, HCN, ammonia, and chlorine may also present and were not accounted for in the risk analysis. Setting an HCl standard under 112(d)(2) and (3) allows the Agency to also address these other HAPs as they are co-controlled by wet scrubbers along with HCl. Commenters from industry urged EPA to retain a risk-based standard but did not challenge EPA's finding or quantification that there would be these enormous health and environmental benefits to setting a standard reflecting MACT to control HCl. The commenters nonetheless urged EPA to retain a risk-based standard, noting that EPA had done so in the predecessor to this rule and for other source categories, and that HCl is a threshold pollutant within the meaning of CAA section 112(d)(4) so that there is a technical basis for such a standard. These arguments do not persuade the Agency to forego the very significant benefits just outlined. However, even if (contrary to the analysis just set out) EPA were inclined to adopt a risk-based standard here, there would be technical obstacles to doing so, as described at the final part of this section. As we noted in the proposed rule, as a general matter, CAA section 112(d) requires MACT standards at least as stringent as the MACT floor to be set for all HAP emitted from major sources. However, CAA section 112(d)(4) provides that for HAP with established health thresholds, EPA has the discretionary authority to consider such health thresholds with an ample margin of safety when establishing emission standards under CAA section 112(d). This provision is intended to allow EPA to establish emission standards other than technology-based MACT standards in cases where a less stringent emission standard will still ensure that the health threshold will not be exceeded, with an ample margin of safety. In order to exercise this discretion, EPA must first conclude that the HAP at issue has an established health threshold and must then provide for an ample margin of safety when considering the health threshold to set an emission standard. We discussed this issue at length in the recent proposed Industrial Boiler MACT. See 75 FR at 32020-33 (June 4, 2010) (declining to propose a risk-based standard for HCl emissions). The legislative history of section 112(d)(4) indicates that Congress did not intend for this provision to provide a mechanism for EPA to delay issuance of emission standards for sources of HAPs. The legislative history also indicates that a health-based emission limit under section 112(d)(4) should be set at the level at which no observable effects occur, with an ample margin of safety. S. Rep. 101-228 at 171-72. The legislative history further states that employing a section 112(d)(4) standard rather than a conventional MACT standard “shall not result in adverse environmental effects which would otherwise be reduced or eliminated.” Id. It is clear that EPA may exercise its discretionary authority under 112(d)(4) only with respect to pollutants with an established health threshold. Where there is an established threshold, EPA has, in the proposed rule on industrial boilers, interpreted section 112(d)(4) to allow us to weigh additional factors, beyond any established health threshold, in making a judgment whether to set a standard for a specific pollutant based on the threshold, or instead follow the traditional path of developing a MACT standard after determining a MACT floor (75 FR 32030). In deciding whether to exercise its discretion for a threshold pollutant for a given source category, EPA has interpreted section 112(d)(4) to allow us to take into account factors such as the following: The potential for cumulative adverse health effects due to concurrent exposure to other HAPs with similar biological endpoints, from either the same or other source categories, where the concentration of the threshold pollutant emitted from the given source category is below the threshold; the potential impacts on ecosystems of releases of the pollutant; and reductions in criteria pollutant emissions and other co-benefits that would be achieved via the MACT standard—the decisive factor here. Each of these factors is directly relevant to the health and environmental outcomes at which section 112 of the Clean Air Act is fundamentally aimed. If EPA does determine that it is appropriate to set a standard based on a health threshold, we must develop emission standards that will ensure the public will not be exposed to levels of the pertinent HAP in excess of the health threshold, with an ample margin of safety. Since any emission standard under section 112(d)(4) must consider the established health threshold level, with an ample margin of safety, in this rulemaking EPA has considered the adverse health effects of the HAP acid gases, beginning with HCl. Research indicates that HCl is associated with chronic respiratory toxicity. In the case of HCl, this means that chronic inhalation of HCl can cause tissue damage in humans. Among other things, it is corrosive to mucous membranes and can cause damage to eyes, nose, throat, and the upper respiratory tract as well as pulmonary edema, bronchitis, gastritis, and dermatitis. Considering this respiratory toxicity, EPA has established a chronic reference concentration (RfC) for the inhalation of HCl of 20 μg/m 3 . ( See http://www.epa.gov/ncea/iris/subst/0396.htm. ) An RfC is defined as an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups 28 ) that is likely to be without an appreciable risk of deleterious effects during a lifetime. The IRIS health assessment evaluated chronic non-cancer risks and did not include an evaluation of carcinogenic effects (on which there are very limited studies). As a reference value for a single pollutant, RfCs do not reflect any potential cumulative or synergistic effects of an individual's exposure to multiple HAPs or to a combination of HAPs and criteria pollutants. Similarly, an RfC evaluation does not focus on potential environmental impacts. 28 “Sensitive subgroups” may refer to particular life stages, such as children or the elderly, or to those with particular medical conditions, such as asthmatics. With respect to the potential health effects of HCl, we know the following: 1. Chronic exposure to concentrations at or below the RfC is not expected to cause chronic respiratory effects; 2. Little research has been conducted on its carcinogenicity. The one occupational study of which we are aware found no evidence of carcinogenicity; 3. There is a significant body of scientific literature addressing the health effects of acute exposure to HCl (California Office of Health Hazard Assessment, 2008. Acute Toxicity Summary for Hydrogen Chloride, http://www.oehha.ca.gov/air/hot_spots/2008/AppendixD2_final.pdf#page=112 EPA, 2001). However, we currently lack information on the peak short-term emissions of HCl from cement kilns which might allow us to determine whether a chronic health-based emission standard for HCl would ensure that acute exposures will not pose health concerns. 4. We are aware of no studies explicitly addressing the toxicity of mixtures of HCl with other respiratory irritants. However, many of the other HAPs (and criteria pollutants) emitted by cement kilns also are respiratory irritants, and in the absence of information on interactions, EPA assumes an additive cumulative effect (Supplementary Guidance for Conducting Health Risk Assessment of Chemical Mixtures. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=20533 ). Cement kilns also emit other acid gases along with HCl, including chlorine (Cl 2 ), HCN and hydrogen fluoride (HF), all of which are HAPs. Like HCl, these HAP gases have established chronic health thresholds below which they are not expected to pose any significant risk of chronic respiratory effects, have no evidence to suggest that they may pose carcinogenic effects, and have an established body of literature regarding acute respiratory health effects. They are also controlled during the process of controlling HCl emissions from cement kilns using a wet scrubber. As such, their health impacts must be taken into account when considering a health-based emission limit for HCl. In the 2006 final rule, EPA did not set any standard for HCl. 29 The Agency reasoned that no further control was necessary for Portland cement emissions of HCl because HCl is a “health threshold pollutant” and human health is protected with an ample margin of safety at current HCl emission levels. 71 FR at 76527. Underlying this conclusion was EPA's analysis of a tiered screening study of dispersion modeling of cement facilities' worst-case and actual HCl emissions. This study was conducted by the Portland Cement Association for about two-thirds of operating U.S. cement plants. Dispersion modeling results were evaluated against the RfC for HCl. 30 The screening analysis involved making conservative assumptions regarding HCl emission concentrations and plants' operating conditions (greater concentrations than known to be emitted and perpetual operation at maximum capacity). All plants in the analysis, with five exceptions, had HCl levels well below a Hazard Quotient (HQ) level of 1.0, the ratio of exposure (or modeled concentration) to the health reference value or threshold level. The remaining five plants in the analysis had HQ levels greater than 1.0 assuming maximum emissions, but less than 1.0 when their actual emissions were used in the dispersion models. Id. at 76528-29. 29 Although the decision not to set a standard in 2006 was based on the authority of section 112(d)(4), we note that the statute in fact states: “the Administrator may consider such threshold level, with an ample margin of safety, when establishing emission standards under this subsection.” Section 112(d)(4), emphasis added. 30 In the previous study EPA also evaluated dispersion modeling results against an acute exposure guideline level (AEGL) below which acute effects would not be expected to occur. However, even given the uncertainties mentioned for short term HCl emissions, that analysis indicated that chronic effects would be of the most concern. At proposal of these amendments, recognizing that the 2006 determination was deficient, if for no other reason because it failed to establish any emission standard whatever, EPA conducted its own analysis to determine what numerical standard for HCl would be necessary to at least assure that, for the sources in the controlled category or subcategory, persons exposed to emissions of HCl would not experience the adverse health effects on which the threshold is based. In order to determine this level, in the proposed rule we conducted a risk analysis of the same 68 facilities analyzed by PCA using a screening level dispersion model (AERSCREEN). Using the site specific stack parameters provided by the PCA and conservative meteorological conditions (taken from the PCA analysis), the AERSCREEN modeling predicted the highest long term ground level concentration surrounding each facility, and used this concentration to back calculate the highest allowable HCl emissions rate that could occur without exceeding the allowable RfC. The results of this analysis indicated that an HCl emission limit of 23 ppmv or less (an order of magnitude higher than the MACT standard) would result in no exceedances of the RfC for HCl for any of the facilities assessed. 31 31 Derivation of a Health-Based Stack Gas Concentration Limit for HCl in Support of the National Emission Standards for Hazardous Air Pollutants from the Portland Cement Manufacturing Industry, April 10, 2009. Based on further consideration, EPA now believes that the 2006 PCA study and analysis has the following deficiencies. First of all, not all cement plants were evaluated (the PCA study covered about two thirds of the plants in the source category), and among those not evaluated were cement plants with the most likelihood of posing risk at ground level from HCl emissions due to use of positive pressure baghouses with monovents or multiple short stacks. Secondly, the analysis did not consider the impacts of the co-emitted acid gases, an important consideration in determining an ample margin of safety. In addition, no data were provided, nor do we have data, on other pollutants in the vicinity of these cement facilities, or background concentration data for HCl to determine cumulative impacts of HCl emissions for these facilities. 32 EPA's analysis of 2009 could not improve on the PCA study, given the lack of robust emissions data for Cl 2 , HF, and HCN, and the lack of any additional data for the cement kilns not included in the original study. As a result, EPA cannot ensure that the resulting derivation of 23 ppmv as a possible health-based emission standard for HCl would result in chronic ambient levels of acid gases that would not pose significant health risks. EPA has no data that would allow us to extend that analysis to cover all acid gases and all facilities. 32 It should be noted that large amounts of site-specific information both on kiln operation and local meteorological information is needed to obtain meaningful results from AERSCREEN and other dispersion models. This information is in the ready possession of the industrial sources themselves, but for unknown reasons, was not provided by industry to EPA either as part of the 2006 PCA analysis or in response to subsequent data solicitations by EPA. In addition to potential health impacts, EPA has evaluated the potential for environmental impacts when considering whether to exercise discretion under section 112(d)(4). When HCl gas encounters water in the atmosphere, it forms an acidic solution of HCl. In areas where the deposition of acids derived from emissions of sulfur and nitrogen oxides are causing aquatic and/or terrestrial acidification, with accompanying ecological impacts, the deposition of HCl could exacerbate these impacts. Being mindful of the explicit legislative history, and in keeping with past EPA practice, it is appropriate to consider potential adverse environmental effects in addition to adverse health effects when setting an emission standard for HCl under section 112(d)(4). The co-emissions of HF, HCN, and Cl 2 from cement kilns could serve to further aggravate these environmental acidification impacts, but EPA has no data to determine these impacts. Although the PCA analysis did not include an assessment of potential environmental effects, for the 2006 final Portland cement rule, EPA conducted its own analysis of potential effects of cement kilns' HCl emissions to wildlife, aquatic life, and other natural resources. The Agency concluded at the time that acute and chronic exposures to expected HCl concentration around cement kilns are not expected to result in adverse environmental toxicity effects. Id. at 76529. EPA accordingly declined to establish any standard for HCl. At this time, we now believe the ecological risk analysis performed in 2006 is insufficient, as it was merely a literature review and not a formal ecological assessment, and, as discussed in the previous paragraphs, it did not cover the impacts of the other acid gases, nor did it cover about one third of the existing cement plants. No additional information was provided during the comment period which addressed these various technical issues, notwithstanding EPA's solicitation of data. Consequently, although EPA is declining to adopt a section 112(d)(4) risk-based standard for HCl emissions from Portland cement facilities for the sound policy reasons discussed herein, we further note that there remain technical issues as to the appropriateness of such a standard even if EPA were inclined to exercise that discretion. We also do not view ourselves as bound by the technical determinations made in the 2006 rulemaking for the reasons just explained. EPA also has concluded that the facts here are distinguishable from those in other rulemakings in which it exercised its discretionary authority under section 112(d)(4). In the case of the Pulp and Paper MACT (63 FR at 18765 (April 15, 1998)), the risk analysis indicated, at the 95 percent confidence interval, that the maximum concentration predicted to which people were estimated to be exposed was 0.3 g/m 3 , 60 times less than the inhalation reference concentration. This is a much lower value than present in the Portland cement risk analysis discussed above. In the case of the Lime Manufacturing NESHAP (67 FR at 78054 (Dec. 20, 2002)), there are two key distinctions. First, the technical information available to EPA covered 100 percent of all lime kilns in the U.S., which is not the case for the Portland cement risk analysis. Second, EPA did a worst case analysis as a supplement to the industry analysis and determined that the highest hazard index under that scenario was 0.21. Based on the EPA analysis determining a health based limit for Portland cement, if we were to allow the same level of risk as we determined in Lime NESHAP analysis, the health based emission limit would be 2 ppmvd, which is almost the same level as the MACT standard we are finalizing in this action. EPA also considers the alternative standard for total chlorine in the Hazardous Waste Combustor MACT (70 FR at 59555 (Oct. 12, 2005)) to be distinguishable. That rule, under the authority of section 112(d)(4) establishes a site-specific risk-based standard for total chlorine (of which HCl is the largest component), whereby, in lieu of meeting the MACT standard, sources may emit total chlorine at higher levels if they demonstrate that their emissions of total chlorine from all hazardous waste combustor sources at a facility do not exceed both acute (one-hour) and chronic (annual) exposure thresholds. The demonstration must account for all relevant site-specific conditions, or be based on worst-case screening assumptions. If sources satisfy these criteria, the amount of their total chlorine emissions is still capped by the technology-based limit to which these sources were previously subject. The site-specific demonstrations, applicability to all combustor sources at a facility, use of acute and chronic health benchmarks, and capping of emission limits are all unique to that rule. e. PM Emissions From Kilns Particulate matter serves as a surrogate for non-volatile metal HAP (a determination upheld for this source category in National Lime Ass'n, 233 F. 3d at 637-39). Existing and new major sources are presently subject to a PM limit of 0.3 lb/ton of feed which is equivalent to 0.5 lb/ton clinker. EPA is amending this standard for major sources, and also adding PM standards for existing and new area source cement kilns. In all instances, EPA is revising these limits because they do not represent MACT, but rather a level which is achievable by the bulk of the industry. See 63 FR at 14198 (March 24, 1998); see also 233 F. 3d at 633 (indicating that the standards for PM were likely legally deficient but that the argument had not been properly preserved for the court to adjudicate). This is not legally permissible. Brick MACT, 479 F. 3d at 880-81. EPA thus does not accept the argument of some commenters that EPA may only amend promulgated MACT standards by means of the periodic review procedures of section 112(d)(6), which does not include re-determining floor levels. Section 112(d)(6)does not indicate that it is the exclusive means of amending MACT standards, and in particular does not speak to a situation where an original floor was palpably short of statutory requirements and where that floor became the ultimate standard. EPA consequently believes it has discretion to reconsider and redo the MACT floor analysis for PM, and to amend the standard as appropriate. Other commenters suggested that even if EPA has such discretion, it would (or should) be limited to a reanalysis of the original database for the 1999 rule and so should not consider kilns' subsequent performance. Were EPA to take that approach here, the floor (and standard) for PM would be more stringent than the floor (and standard) in this rule. 33 Because EPA considers the database for the current rule to be more representative of performance capabilities of best performing kilns than the sparser 1999 database, EPA is basing its determination on the more representative data. 33 Calculation of PM MACT Floor Based on Data in 1998 Proposal. July 7, 2010. EPA is setting a PM standard based on MACT for existing and new area source cement kilns. As noted at proposal, Portland cement kilns are a listed area source category for urban HAP metals pursuant to section 112(c)(3), and control of these metal HAP emissions (via the standard for the PM metal surrogate) is required to ensure that area sources representing 90 percent of the area source emissions of urban metal HAP are subject to section 112 control, as required by section 112(c)(3). EPA has determined that this standard should reflect MACT, rather than GACT, because there is no essential difference between area source and major source cement kilns with respect to emissions of either HAP metals or PM. Thus, the factors that determine whether a cement kiln is major or area are typically a function of the source's HCl or formaldehyde emissions, rather than its emissions of HAP metals. As a result, there are kilns that are physically quite large that are area sources, and kilns that are small that are major sources. Both large and small kilns have similar HAP metal and PM emissions characteristics and controls. Given that EPA is developing major and area source standards for PM at the same time in this rulemaking, a common control strategy consequently appears warranted for these emissions. We thus have included all cement kilns in the floor calculations for the final PM standard, and have developed common PM limits based on MACT for both major and area sources. i. Floor Determination. At proposal we had compiled PM stack test data for 45 kilns from the period 1998 to 2007. EPA ranked the data by emissions level and the lowest emitting 12 percent, 6 kilns, was used to develop the proposed existing source MACT floors of 0.085 and 0.08 lb/ton clinker for new and existing sources respectively. Commenters noted that we had omitted some of the data already submitted to EPA in developing the MACT floor. In addition, we noted for two of the best performing facilities we had only one emissions test. Therefore we requested these sources to submit additional PM emission test data and the source sent two additional PM emissions tests for each kiln to allow us to better characterize emissions variability. We modified the PM data base to reflect these submissions. Another change made since proposal is that we have changed the compliance requirement to require a PM CEMS. This requires that we establish an averaging period. We chose a period of 30 days (rolling average) to be consistent with requirements for mercury and THC, and because PM emissions on a lb/ton basis are affected by raw mill cycles (typically encompassed within 30-days, see 74 FR at 21144) for kilns with in-line raw mills. We have converted the concentrations obtained from 3-hour tests into 30-day values by means of the UPL equation previously described. It should be noted that due to the longer averaging periods, the actual limit will be a lower number compared to the shorter compliance interval in the proposed rule (30 days versus a three hour test). This damping of variability when a longer averaging period is used is well established where continuous monitors have been used to measure emissions, and is also accounted for in the “m” term of the UPL equation. The results of the new MACT analysis are shown in Table 8. Table 8—PM MACT Floor Kiln PM emissions (lb/ton clinker) 1 0.01 2 0.01 3 0.01 4 0.03 5 0.04 6 0.04 MACT—Existing Average 0.02 Variance 0.001 UPL 0.04 MACT—New Average 0.01 Variance 0.00001 UPL 0.01 EPA proposed use of PM CEMS as an alternative to using a bag leak detector, and also solicited comment on requiring their use generally. 74 FR at 21157. As we noted there, performance specifications for PM CEMS are now available, and continuous monitors “give a fa [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%3A2010-21102. Public record. Not legal advice.