EPA's Responses to Public Comments on EPA's National Emission
Standards for Hazardous Air Pollutants from Coal- and Oil-Fired Electric Utility Steam Generating Units
                                 December 2011
                                 Volume 1 of 2

Comments, letters, and transcripts of the public hearings are also available electronically through
   http://www.regulations.gov by searching Docket ID EPA-HQ-OAR-2009-0234.
                                   FOREWORD

This document provides the EPA's responses to public comments on the EPA's Proposed National Emission Standards for Hazardous Air Pollutants from Coal- and Oil-fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional, and Small Industrial-Commercial-Institutional Steam Generating Units. The EPA published a Notice of Proposed Rulemaking in the Federal Register on May 3, 2011, at 76 FR 24976. The EPA received comments on this proposed rule via mail, e-mail, facsimile, and at three public hearings held in Chicago, Illinois; Atlanta, Georgia; and Philadelphia, Pennsylvania, in May 2011. Copies of all comments submitted and transcripts for the public hearings are available at the EPA Docket Center Public Reading Room. Comments, letters, and transcripts of the public hearings are also available electronically through http://www.regulations.gov by searching Docket IDs EPA-HQ-OAR-2009-0234 (NESHAP action) and EPA-HQ-OAR-2011-0044 (NSPS action).

This document contains responses to comments on the NESHAP only; responses to comments on the NSPS action are in a separate Response to Comments document. Due to the size and scope of this rulemaking, the EPA summarized a limited amount of major comments in the preamble of the final rule. This document contains a summary of all significant comments provided by each commenter extracted from the original letter or public hearing transcript.

Appendix A of this document provides a list of public hearing speakers and their affiliation. Appendix B of this document provides a list of commenters and their affiliation along with the associated document control number (DCN). For each comment, the DCN is provided along with the comment summary. For purposes of this document, the text within the comment summaries was provided by the commenter(s) and represents their opinion(s), regardless of whether the summary specifically indicates that the statement is from a commenter(s) (e.g., "The commenter states" or "The commenters assert"). The comment summaries do not represent the EPA's opinion unless the response to the comment specifically agrees with all or a portion of the comment. In some cases the same comment was submitted by two or more commenters through submittal of a form letter prepared by an organization, by the commenter incorporating by reference the comments in another comment letter, or by the commenter providing identical or similar language independently. Rather than repeat these comment excerpts for each commenter, the EPA has listed the comment excerpt only once and provided a list of all the commenters who submitted the same form letter or otherwise incorporated the comments by reference in Tables 9A-1 through 9A-21 and 9B-1 through 9B-5 of section 9 of this document and Table 10-1 of section 10 of this document, respectively.

Several of the EPA's responses to comments are provided immediately following each comment summary. However, in instances where several commenters raised similar or related issues, the EPA has grouped these comments together and provided a single response after the last comment summary in the group. In some cases, the EPA provided responses to specific comments or groups of similar comments in the preamble to the final rulemaking. Rather than repeating those responses in this document, the EPA has referenced the preamble or the appropriate technical support document for a description of the analysis included in the final rule.

As both the NESHAP and NSPS actions were included in the same proposal package, many commenters submitted comments to this rulemaking docket that were specific to the NSPS action. Some commenters submitted a single DCN with comments on both rules, while others submitted a separate DCN specific to each action. Many commenters submitted identical comments to both dockets. In order to reduce duplicative comments, we have removed from this document comments associated with the NSPS action. For this reason, the EPA encourages the public to read the Response to Comment document prepared for the NSPS action.

                               TABLE OF CONTENTS

CHAPTER 1: LEGAL  -  GENERAL/APPROPRIATE AND NECESSARY FINDING/REQUEST FOR EXTENSION OF COMMENT PERIOD/OTHER
1A - Legal: General legal comments not related to the Appropriate and Necessary Finding that use case law and CAA statutory text to recommend a fundamentally different approach to the rulemaking
1B - Legal Aspects of Appropriate and Necessary Finding
1C - New Technical Analyses: General Comments
1D - Hg Emissions
1E - Hg Deposition Modeling
1F - National-scale Hg Risk TSD
1G - Non-Hg Case Studies
1H - Local-scale Hg case study
1I - Ecosystem Impacts from HAP
1J - Legal: Request for Extension of Comment Period
1K - Legal: Other

CHAPTER 2: APPLICABILITY
2A - Applicability: Treatment of area sources
2B - Applicability: Section 112 rules, Industrial Boiler MACT (DDDDD and JJJJJJ)
2C - Applicability: Section 129 rule, CISWI
2D - Applicability: Exemptions or de minimis size threshold
2E - Applicability: Other

CHAPTER 3: SUBCATEGORIZATION
3A - Subcategorization: Coal (>8,300 Btu/lb) (Proposed)
3B - Subcategorization: Applicability: Coal (<8,300 Btu/lb)
3C - Subcategorization: IGCC (Proposed)
3D - Subcategorization: Oil - Liquid (Proposed)
3E - Subcategorization: Oil - Solid (Proposed)
3F - Subcategorization: New suggested categories
3G - Subcategorization: Other

CHAPTER 4: MACT FLOOR/MACT BEYOND-THE-FLOOR/DATA
4A - MACT Floor Methodology
4B - MACT Floor Results
4C - Beyond-the-Floor Analysis
4D - Work Practice Standards
4E - Alternative Limits
4F - Format of the Standard
4G - ICR

CHAPTER 1: LEGAL  -  GENERAL/APPROPRIATE AND NECESSARY FINDING/REQUEST FOR EXTENSION OF COMMENT PERIOD/OTHER
1A - Legal: General legal comments not related to the Appropriate and Necessary Finding that use case law and CAA statutory text to recommend a fundamentally different approach to the rulemaking
Commenters: 17383, 17620, 17623, 17648, 17689, 17702, 17723, 17725, 17728, 17732, 17751, 17754, 17756, 17758, 17768, 17775, 17799, 17813, 17820, 17838, 17848, 17851, 17855, 17867, 17873, 17877, 17878, 17880, 17904, 17930, 18014, 18019, 18024, 18033, 18421, 18424, 18425, 18432, 18487, 19121, 8443, 19536/19537/19538, 18932, 18023
1. Support for a health-based alternative standard under CAA section 112(d)(4).
a. General support.
Comment 1: Multiple commenters (17702, 17775, 17623, 17799, 17877, 17904, 18023, 18443) state that to avoid setting MACT limits that are far more stringent than necessary to protect public health the EPA has discretion and should have set an alternative health-based emission limit for the acid gas HAP's under the authority of section 112(d)(4). According to the commenters, health-based standards can be established for only those HAPs for which a "health threshold" has been established and the EPA has defined that threshold to be "the level of concentration of a chemical under which no health effects are expected from exposure" over a lifetime. See Chlorine and Hydrochloric Acid Emissions From Chlorine Production, 68 Fed. Reg. 70,948, 70,951 (Dec. 19, 2003); Mercury Emissions From Mercury Cell Chlor-Alkali Plants, 68 Fed. Reg. 70,904, 70,915. The commenters state that the second criteria that must be satisfied to set a health-based alternative is that the standards must be set at levels that are not expected to cause adverse health effects with an ample margin of safety. The commenters state that HAP acid gases emitted by EGUs are all non-carcinogens and have defined health thresholds in the form of reference concentrations ("RfC") and the RfC's for these HAPs are protective of public health with an ample margin of safety.
Comment 2: Several commenters (17623, 17867, 18424, 18425, 17820) encourage the EPA to set health based standards for HCl and other threshold pollutants as provided for in CAA section 112(d)(4) for which the agency can determine a level that avoids adverse health effects with an ample margin of safety. According to the commenters, a health-based standard can avoid unnecessary costs.
Comment 3: Commenter 17728 states that the EPA should set health based limits for acid gases under section 112(d)(4) "since Congress added section 112(d)(4) to avoid the situation where the unthinking application of MACT limits to a given source category results in emissions standards that are far more stringent than necessary to protect public health."
Comment 4: Commenter 17855 states that because there were no "plausible health risks to the public associated with emissions of non-mercury (Hg) HAPs" the EPA should establish health based standards under CAA section 112(d)(4). According to the commenter, non-Hg risk assessments for a number of facilities demonstrated that these facilities have impacts of non-Hg HAP "much lower than health threshold levels with an ample margin of safety." The commenter asserts that the EPA's MACT limits are not justified or cost-effective.
Commenter 17775 states that modeling conducted by both the EPA and this commenter has consistently shown that all offsite exposures to HAP acid gas emissions for coal-fired EGUs are well below the reference concentrations ("RfCs") or reference exposure levels ("REL") for those HAP acid gases. As a result, states the commenter, the EPA should set alternative health-based emission limits for those HAPs under CAA section 112(d)(4). A properly constructed alternative health-based limit would avoid unnecessary and inefficient regulation that yields no public health benefits from reduced HAP acid gas emissions.
Comment 5: Commenter 18023 states that the EPA has sufficient information to establish health-based emission limits. The commenter refers to the 1998 Report to Congress as well as the refined modeling of 16 plants that was performed to support the proposed rule. According the commenter, a standard can be developed using only (1) the health threshold, and (2) the Chi/Q value for a plant known to have poor dispersion characteristics. The commenter states that division of the RfC or REL by the Chi/Q value produces the emission rate Q, corresponding to concentrations equal to the RfC, and this Q result is a health-based emission limit (in g/s) that could be used in place of a conventional MACT standard.
Commenter 18024 states that the EPA should use its authority under CAA section 112(d)(4) to provide a health-based alternative to demonstrate compliance with mathematically derived HAP standards for uncontrolled liquid oil-fired boilers if an applicant can demonstrate that such emissions do not exceed established air toxics thresholds. According to the commenter, relatively few liquid oil-fired EGU boilers exist in the U.S.; of those, many fire primarily natural gas but retain liquid fuel as backup. The commenter states that due to the present and projected economics of competing with higher efficiency natural gas combined cycle generating units, older natural gas-fired steam-electric EGUs increasingly operate at low annual capacity factors and most have excellent dispersion characteristics. At best, states the commenter, existing No. 6 oil-fired EGUs may be equipped with ESPs for particulate control; however, no known No. 6 oil-fired or dual-fuel fired EGUs operate with any Hg or acid gas add-on control technology. According to the commenter, the proposed MACT Floor limits do not reflect any emission control technology or strategy, but rather simply reflect natural variations and data limitations in the available stack test data. According to the commenter, this is not a useful way to establish numerical emission limits, since existing EGUs have no demonstrated air pollution control retrofit strategy to achieve continuous compliance.
Commenter 18024 suggests that for oil backup that the EPA provide an alternative to the numerical number if it can be demonstrated that such alternative limit would result in no significant incremental health risk to the community. According to the commenter, a health-based demonstration alternative would provide a safety valve such that if a given existing EGU that could not demonstrate compliance with one particular MACT Floor limit, the owner could propose an alternative limit based on a demonstration of lack of adverse health impacts on a case-by-case basis.
Commenter 17656 states the EPA uses health concerns as the rationale for further regulation of the utility sector. Thus, the commenter is confused as to why the EPA declined to simply adopt health-based emissions standards, in lieu of MACT emission limits, for EGUs. The commenter states that the agency has the flexibility to do so under CAA section 112.
Commenter 18428 states that the EPA has not provided any rationale for regulating HCl, and they should proceed to develop appropriate health-based thresholds under section 112(d)(4) in addition to subcategorizing by coal rank.
Several commenters (17705, 17812, 17821) state the EPA should use the agency's discretion to set an alternative health-based emission limit for acid gas HAPs. According to the commenters, as an alternative to the currently proposed NESHAP for acid gas HAPs, the EPA should set an alternative health-based emission limit under CAA section 112(d)(4). The commenters state that section 112(d)(4) provides an alternative to establishing limits for a given source category that are more stringent than necessary to protect public health. Section 112(d)(4) states:
      "With respect to pollutants for which a health threshold has been established, the Administrator may consider such threshold level, with an ample margin of safety, when establishing emissions standards under this subsection."
According to the commenters, this section provides the EPA with a mechanism to avoid standards based on application of MACT that produce no public health benefits but require large compliance expenditures by the affected industry.
The commenters state that the EPA has substantial information to support setting alternative health-based limits for the acid gas HAP under CAA section 112(d)(4). As the EPA notes in the preamble to the proposed rule, state the commenters, two factors must be met in order for the EPA to set alternative HAPs limits under section 112(d)(4): first, the pollutants under consideration for a section 112(d)(4) limit must have established health thresholds and, second, any section 112(d)(4) standard must provide an ample margin of safety when considering the health threshold.
The commenters state that the HAP acid gases emitted by EGUs are non-carcinogens having defined health thresholds. For compounds, like the acid gases, that affect public health as a result of inhalation, these thresholds take the form of a reference concentration ("RfC"). Although not defined in the CAA, state the commenters, the EPA interprets a health threshold to refer to "the level of concentration of a chemical under which no health effects are expected from exposure" over a lifetime.
Commenters 17705 and 17774 note that the EPA's analyses indicate that acid gases from coal-fired power plants do not result in exceedances of any RfC. The commenters state that the EPA references a specific study the agency used to determine whether to use health-based standards for the acid gas HAPs. In this study, the EPA defines RfC to mean "an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime." The study focused on 16 coal-fired facilities as worst case test cases in order to determine whether health-based standards were appropriate. According to the commenters, this study did not find potential for coal-fired utilities to exceed any RfC and therefore provides justification for the EPA to set health-based standards.
Commenter 17705 states that in the preamble to the proposed rule, the EPA discusses its consideration of a section 112(d)(4) limit for the acid gas HAPs. According to the commenter, that discussion adds three factors that do not appear anywhere in section 112(d)(4) that the agency states are "directly relevant to the health and environmental outcomes at which CAA section 112 is fundamentally aimed." These factors are: (1) the potential for cumulative adverse health effects due to concurrent exposure to other HAPs with similar biological endpoints, from either the same or other subcategories, where the concentration of the threshold pollutant emitted from the given source category is below the threshold; (2) the potential impacts on ecosystems of releases of the pollutant; and (3) reductions in criteria pollutant emissions and other co-benefits that would be achieved by a MACT standard.
According to the commenter, considerations of cumulative effects, impacts on the environment, and the co-benefits of a MACT standard should not be deciding factors of whether or not to establish health-based emission limits under section 112(d)(4) because standards under section 112 should be focused on HAP emissions from the regulated source category that impact health. Commenter strongly encourages the EPA to remove the current standards for acid gas HAPs and set health-based standards for these pollutants as provided for in section 112(d)(4).
Comment 6: Commenter 17821 states that selenium (Se), mainly in the form SeO2, emitted from utility units, are only a tiny fraction of HCl and HF, and therefore make a de minimis contribution to acidification. The commenter states that compared to acidification due to SO2 and NOX emissions, Se emissions are even less significant, and work performed by EPRI shows the adverse health effects due to air emissions of Se are insignificant. Therefore, states the commenter, the EPA should consider setting a health-based standard for Se and remove it from the list of regulated non-Hg metals, and furthermore, because there is no significant correlation between Se and condensable PM, there is no justification for a total PM standard. The commenter states that thus regulation of non-Hg metals can be accomplished through use of filterable PM as a surrogate.
b. The CAA requires a health-based standard.
Comment 7: Several commenters (17754, 17838, 18023) state that the emission limits for non-Hg HAPs should not be technology-based standards (i.e., MACT standards) but rather health-based standards. According to the commenters, the CAA does not authorize the EPA to effectively substitute a technology-based analysis for the health-based evaluation expressly required by the statute.
c. The EPA impermissibly declined to establish a health-based standard under CAA section 112(d)(4).
Comment 8: Commenters 17775 and 18023 state that in the preamble discussion of establishing health-based emission limits for acid gas HAP the EPA added three factors that do not appear in section 112(d)(4). According to the commenters, the EPA added the following factors: (1) the potential for cumulative adverse health effects due to concurrent exposure to other HAP with similar biological endpoints, from either the same or other subcategories, where the concentration of the threshold pollutant emitted from the given source category is below the threshold; (2) the potential impacts on ecosystems of releases of the pollutant; and (3) reductions in criteria pollutant emissions and other co-benefits that would be achieved by a MACT standard. To the extent that concurrent impacts are considered, the commenters suggest this could be addressed by using an additional margin of safety.
Comment 9: Commenter 17799 states that the EPA has set health-based standards in other MACT proceedings and that the EPA should set health-based standards because the analysis demonstrates that risks from non-carcinogens from EGUs are well below threshold levels. According to the commenter, the EPA declined to set health based standards "based on reasoning irrelevant to the source category." According to the commenter, the EPA reasoned that coal-fueled units are likely to be in areas where other sources of HAPs exist, thereby creating a significant risk of harmful exposure. Based on utilities' presumed proximity to other HAP sources, states the commenter, the EPA concluded that health-based standards would not apply in this case. Furthermore, states the commenter, the EPA focused on the PM2.5 co-benefits of reducing hydrogen chloride (HCl), hydrogen fluoride (HF), and other acid gases with a conventional MACT standard rather than considering whether HCI or HF would need a health-based standard. Finally, states the commenter, the EPA also focused on the environmental effects of HCI, HF, and other acid gas HAP when deciding not to set a health-based standard.
Comment 10: Several commenters (17848, 17848, 17930, 18033) state that CAA section 112(d)(4) allows health-based standards provided they are protective of public health with an ample margin of safety and that the EPA has used this approach in the past. The commenters note that the EPA declined to exercise this authority because of the potential for cumulative health effects, impacts on ecosystems, and reductions in criteria pollutants and other co-benefits that would be achieved by the proposed MACT. According to the commenters, co-benefits of SO2 and PM2.5 reductions should not override the discretion to establish health based standards.
Comment 11: Several commenters (17813, 18014, 18033, 17725) state that the EPA's failure to set section 112(d)(4) standards "runs counter to the CAA." According to the commenters, none of the acid gases are listed as carcinogenic and they have defined health thresholds. The commenters state that the EPA does have the tools and expertise to establish section 112(d)(4) standards as evidenced by 2004 boiler MACT. Additionally, state the commenters, the EPA has already established a precedent for addressing HCl as a threshold pollutant in promulgating the Pulp and Paper NESHAP (1998) and the Lime Manufacturing NESHAP (2002) where the agency wholly exempted HCl from the MACT requirement. According to the commenters, citing the loss of co-benefits from criteria pollutants is not a permissible use of discretion under section 112(d)(2); there is a prohibition on the addition of any criteria pollutant to section 112 HAP list (with a single exception for certain precursor pollutants not relevant for this case) and this extends to any rule that in effect treats a criteria pollutant as a HAP.
Comment 12: Commenter 17813 states that the EPA takes the position that establishing a section 112(d)(4) HCl standard is inappropriate because information is not available to show acute exposures will not pose health concerns. According to the commenter, the EPA's analysis and preamble discussion that it believes that health risks due to acids gas exposures including HCl is minimal.
Comment 13: Commenter 18019 states that the EPA rejected establishing health-based standards for acid gases but statements such as "in the case of HCl, this means that chronic inhalation of HCl can cause tissue damage in humans" without putting it into the context of the of the actual contributions of EGUs to ambient concentrations and whether there are any expected effects at those levels are inflammatory.
Comment 14: Although HCl emissions meet the statutory requirements for the establishment of a health-based emission limit under section 112(d)(4), commenter 17774 notes that the EPA did not propose such standards. According to the commenter, the agency's reasons for doing so are flawed and considered impermissible factors. The commenter states that the EPA explained that coal-fired units are likely to be located in areas where other sources emit HAPs and that overall HCl exposure levels would be harmful. The commenter states that the EPA did not provide any factual background for this assertion but, based on utilities' presumed proximity to other HAP sources, concluded that health-based standards would be inappropriate in this rulemaking. Furthermore, states the commenter, the EPA focused on the co-benefits of reducing HCl and other acid gases with a conventional MACT standard rather than considering whether HCl could be adequately controlled using a health-based standard. Finally, states the commenter, the EPA cited the environmental effects of HCl and other acid gas HAP as reasons for not setting a health-based standard.

Commenter recognizes that the EPA has broad discretion when deciding whether to set a health-based standard, but the EPA may not decline to set a standard based on considerations beyond the source category and purview of section 112. The commenter states that the EPA should only base its determination on emissions from EGUs, not emissions of other sources, such as those emitting HAPs "likely" to be located near EGUs. Similarly, states the commenter, the EPA should not consider environmental effects or co-benefits and should focus solely on EGU emissions before declining to use health-based standards. According to the commenter, if the EPA had done so in the first place, it most likely would have found health-based standards appropriate because coal-fired utilities do not have the potential to exceed any RfC. As a result, the commenter strongly urges the EPA to reconsider its decision and set health-based standards for HCl and other threshold pollutants.

2. Support for EPA's approach to not use section 112(d)(4) to establish a health-based alternative (HBA) standard.

a. General support that there is insufficient information to establish an HBA.
Comment 15: Commenter 17648 states that "EPA has no information available to support health-based regulations under section112(d)(4) for HCl or other acid gases, including HF, SeO2, and HCN. According to the commenter, the agency has not adopted health-based standards for HF, SeO2, and HCN in any NESHAP, and there is no evidence upon which the agency reasonably could base a decision to implement such standards in the Toxics Rule." The commenter states that it would be inappropriate to exercise the discretion to establish health-based standards under section 112(d)(4) "in light of several relevant factors, including the potential for cumulative and synergistic adverse health effects from concurrent exposure to other HAPs and criteria pollutants with similar biological endpoints and the potential environmental impact from HCl."
Comment 16: Several commenters (17620, 18421, 18487) state that they support the rejection of alternative compliance limits under section 112(d)(4) where there is insufficient scientific information to establish a safe threshold for the HAP at issue.
Comment 17: Several commenters (19536, 19537, 19538) state that if the EPA invokes section 112(d)(4) authority to consider setting a health-based alternative standard, the agency must conduct that evaluation on a pollutant-specific basis with respect to pollutants for which a health threshold is already established. See Fed. Reg. 25,049. According to one commenter, even if HCl could reasonably serve as a surrogate for the other acid gases in setting MACT floors (a point which the commenters do not concede), it cannot be a surrogate in health-based standard setting, because the EPA must base any section 112(d)(4) health-based standard on a NOAEL threshold for the toxic pollutant in question. The commenters note that the EPA properly concluded that it is not accurate or technically correct to select one acid gas (HCl) with one health endpoint to serve as a surrogate for another acid gas (HF or HCN) with a different health endpoint in health-based standard setting "with an ample margin of safety," as the resulting surrogate-based health threshold simply does not address or relate to the adverse health effects of the other HAP. 76 Fed. Reg. 25,049. According to the commenters, the effects of acid gases vary significantly. Commenters state that Cl2, HF, and HCN present in lower amounts as compared to HCl but are more toxic.
Comment 18: Several commenters (19536, 19537, 19538) state that the "ample margin of safety" language in section 112(d)(4) means at the very least that any standard that is set under this authority must be sufficient to protect against significant unforeseen consequences, particularly where the agency is aware that those consequences may occur, but simply does not have enough evidence about them. See, e.g., EDF v. EPA, 598 F.2d 62, 81 (D.C. Cir. 1978)(holding that the phrase `ample margin of safety' in the Clean Water Act's toxic provisions required the EPA to protect against as yet unidentified risks to human health, including those "which research has not yet identified.").
Comment 19: Several commenters (19536, 19537, 19538) state that the "established health threshold" under 112(d)(4) must be based on a NOAEL and not the RfC for the acid gases. According to the commenters, even if an RfC approach is used, the EPA noted that no RfC is available for Cl2 and HF is not one of the 504 substances within the IRIS so no RfC is available for that gas. Additionally, according to the commenters, the EPA has "low confidence" in the RfC values for HCl and HCN.
Comment 20: Several commenters (19536, 19537, 19538) state that short-term exposure and effects are important when considering whether a section 112(d)(4) standard is appropriate. According to the commenters, based on Cal EPA standards, Cl2, HF, and HCN are approximately 10-fold more toxic than HCl on a weight-standardized basis for short-term exposures. The commenters state that additionally, respiratory effects are likely after short to exposure to high concentrations of acid gases.
Comment 21: Several commenters (19536, 19537, 19538) state that none of the four acid gases (HCl, CL2, HF, or HCN) has undergone a complete evaluation and determination of human carcinogenic potential under the IRIS program. The commenters state that the absence of information does not provide evidence that there is an absence of risk. According to the commenters, because section 112(d)(4) requires any alternative to a MACT standard to be based on both "no adverse effects" and an "ample margin of safety," the incomplete nature of this evaluation makes a section 112(d)(4) standard unavailable for these pollutants.
b. Section 112(d)(4) standards include requirement to consider environmental impacts.
Comment 22: Several commenters (19536, 19537, 19538) state that, as the EPA has previously indicated and the legislative history supports, the Administrator must evaluate the potential for environmental impacts when considering whether to exercise her discretion under section 112(d)(4) and cite the proposed Industrial Boiler MACT, 75 Fed. Reg. 32,006, 32,031 (June 4, 2010)(S. Rep. No. 228, 101[st] Cong., 1[st] Sess. (1989) at 171).
c. Section 112(d)(4) standards require consideration of synergistic effects.
Comment 23: Several commenters (19536, 19537, 19538) state that section 112(d)(4) requires consideration of synergistic effects and the EPA cannot disregard the fact that there are other sources of air toxics in the vicinity. The commenters note that the EPA discusses the use of a hazard index (HI) to account for the interactions of the HAPs. However, the commenters disagree with the EPA's assumption that all endpoints can be assumed to interact additively. The commenters state that HCN is a known neurotoxin and therefore its health effects are not additive with the other acid gases. In addition, one commenter notes the wide variety of HAP and other pollutants emitted in close proximity to EGUs makes predicting and assessing the possible mixtures is all but impossible.
Response to Comments 1 - 23: The EPA is not adopting an emissions standard based on its authority under CAA section 112(d)(4) in the final rule. The EPA first notes that the agency's authority under CAA section 112(d)(4) is discretionary. That provision states that the EPA "may" consider established health thresholds when setting emissions standards under CAA section 112(d). By the use of the term "may," Congress clearly intended to allow the EPA to decide not to consider a health threshold even for pollutants which have an established threshold. As explained in the preamble to the proposed rule, it is appropriate for the EPA to consider relevant factors when deciding whether to exercise its discretion under CAA section 112(d)(4), and the language of that provision does not prevent the agency from considering factors not specifically enumerated. To interpret the statute as some commenters suggest would effectively require the agency to establish CAA section 112(d)(4) standards whenever there is an established health threshold for a HAP. The EPA has considered the public comments received and is not adopting an emissions standard under CAA section 112(d)(4) for the reasons explained below and in the proposed rule.
First, as explained in the preamble to the proposed rule, the EPA continues to believe that the potential cumulative public health and environmental effects of acid gas emissions from EGUs and other acid gas sources located near EGUs supports the agency's decision not to exercise its discretion under CAA section 112(d)(4). The EPA did not receive information regarding facility-specific emissions of all the acid gases from EGUs as well as sources which may be co-located with EGUs or nearby such sources. Additional data were also not provided during the comment period, and the data already in hand regarding these emissions are not sufficient to support the development of emissions standards for any of the EGU subcategories under CAA section 112(d) that take into account the health threshold for acid gases, particularly given that the CAA requires the EPA's consideration of health thresholds under CAA section 112(d)(4) to protect public health with an ample margin of safety. Commenters' assertions that the EPA has sufficient data, even for HCl, are incorrect, and it appears that they believe that the EPA can establish a CAA section 112(d) standard for HCl and ignore the other acid gas HAP. In addition, the concerns expressed by the EPA in the proposal regarding the potential environmental impacts and the cumulative impacts of acid gases on public health were not assuaged by the comments received.
As explained in the preamble to the proposed rule, the EPA also considered the co-benefits of setting a conventional MACT standard for HCl. The EPA considered the comments received on this issue and continues to believe that the co-benefits are significant and provide an additional basis for the Administrator to conclude that it is not appropriate to exercise her discretion under CAA section 112(d)(4). The EPA disagrees with the commenters who stated that it is not appropriate to consider non-HAP benefits in deciding whether to invoke CAA section 112(d)(4). Although MACT standards may directly regulate only HAP and not criteria pollutants, Congress did recognize, in the legislative history to CAA 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. See S. Rep. No. 101 - 228, 101st Cong. 1st sess. at 172. The EPA consequently does not accept the argument that it cannot consider reductions of criteria pollutants, for example in determining whether to take or not take certain discretionary actions, such as whether to adopt a risk-based standard under CAA section 112(d)(4). There appears to be no valid reason that, where the EPA has discretion in what type of standard to adopt, the EPA must ignore controls which further the health and environmental outcomes at which CAA section 112(d) is fundamentally aimed because such controls not only reduce HAP emissions but emissions of other air pollutants as well.
Thus, the issue being addressed is not whether to regulate non-HAP under CAA section 112(d) or whether to consider other air quality benefits in setting CAA section 112(d)(2) standards  -  neither of which the EPA is doing  -  but rather whether to make the discretionary choice to regulate certain HAP based on the MACT approach and whether the EPA must put blinders on and ignore collateral environmental public health benefits when choosing whether or not to exercise that discretion. The EPA knows of no principle in law or common sense that precludes it from doing so.
The EPA properly listed EGUs pursuant to CAA section 112(n)(1)(A) and the EPA must establish CAA section 112(d) standards for all HAP emitted from EGUs. See CAA section 112(c)(2) (requiring listed sources be regulated pursuant to section 112(d)); see Sierra Club v. EPA, 479 F.3d 875, 883(D.C. Cir. 2007) (finding that "EPA has a `clear statutory obligation to set emission standards for each listed HAP'") (quoting National Lime Ass'n v. EPA, 233 F.3d 625, 634 (D.C. Cir. 2000).
The EPA is not adopting the one commenter's suggestion that the EPA not regulate Se based on the allegedly low levels of SeO2. The EPA agrees that SeO2 emissions from EGUs generally represent significantly less mass than emissions of HCl or HF from EGUs, but disagrees with the commenter's assertion that emissions of SeO2 from all EGUs are well enough characterized to support the claim that they contribute minimally to either environmental acidification or adverse chronic human health effects. The analysis conducted by EPRI did not include an adequate amount of SeO2 emission measurement data to support this claim, and the commenter provided no additional data in this regard. As a result, the EPA does not have the information needed to support the development of a health-based standard for selenium.
3. Alternative approach including cap and trade.
Comment 24: Commenter 17723 states that the EPA's approach to the Appropriate and Necessary Finding was to determine that controls were available. According to the commenter, the "mere existence and availability" of controls is not sufficient to mandate universal deployment. The commenter notes that when CAA section 112 was enacted Congress was aware of the availability of certain controls for power plant emissions. According to the commenter, Congress recognized that applying these controls at all existing EGUs would be a "cost prohibitive" way to achieve emission reductions. Instead, Congress required controls through title IV on a limited basis. The commenter states that basing the decision to require universal controls merely on their existence does not satisfy the original intent of Congress.
Response to Comment 24: Congress specifically directed the agency to evaluate "alternative control strategies" for regulating HAP emissions from EGUs in the Utility Study. See CAA section 112(n)(1)(A). The EPA considered in the Utility Study pre-combustion controls, combustion controls, post-combustion controls, and alternative mechanisms to reduce HAP emissions from EGUs (e.g., energy efficiencies). The EPA reasonably interpreted this direction as Congress's interest in understanding whether standards under CAA section 112 would be achievable for EGUs. In fact, there are controls available that allow sources to comply with the standards in the final rule and, based on the data available, at least 180 existing EGUs are able to comply with one or more of the final Hg, PM, and HCl limits under their current control configuration using a variety of control technologies and at least one EGU is able to comply with all three of the new-source limits.
The EPA reasonably considered the availability of controls when determining whether it was appropriate and necessary to regulate EGUs under CAA section 112 consistent with CAA section 112(n)(1)(A). However, the EPA did not state in the proposed rule that it based its finding only on the availability of controls or that the finding could be based solely on the availability of controls.
Comment 25: Commenter 17723 states that the "manipulation of power markets does not justify a finding of necessary and appropriate." According to the commenter, the EPA's rationale for including non-Hg HAP is the desire to alter the economics of electrical generation to favor lower emitting technologies. See 76 Fed. Reg. 24979. The commenter does not believe that raising the cost of coal-fired power would have ranked high on the list of criteria for a finding of necessary and appropriate. The commenter points to title IV of the CAA noting that cost-efficiency was the hallmark of that program and that Congress could have mandated natural gas but chose not to and maintained coal as the primary generating fuel. Second, the commenter notes that the Power Plant and Industrial Fuel Use Act of 1978 had as its purpose "to encourage and foster the greater use of coal and other alternate fuels, in lieu of natural gas and petroleum, as a primary energy source." (42 U.S.C. section 301(b)(2)).
Response to Comment 25: The EPA does not agree with the commenter's interpretation of CAA section 112. We maintain that our interpretation of the statute and our authority there-under is reasonable for the reasons set forth in the proposed rule. We specifically disagree with commenter's interpretation as it relates to the title IV Acid Rain program, because we do not believe the manner in which EGUs were regulated under that program alters the agency's responsibility when regulating EGUs under CAA section 112.
The commenter incorrectly characterizes the agency's legal rationale for the EGU NESHAP. The basis for listing and regulating EGUs under CAA section 112 was in 2000, and remains today, that HAP emissions from EGUs pose a hazard to public health and the environment. A consequence of the rule will be that uncontrolled EGUs that Congress believed would retire decades ago will have to install controls to keep operating.
Further, the commenter's assertion that the title IV Acid Rain program currently requires pollution controls for all EGUs is not accurate. The acid rain program is a trading program that allows some sources to run uncontrolled for NOX and SO2 if they purchase emission allowances.
Comment 26: Commenter 17768 states that the EPA has the legal authority to use a market based cap-and-trade program under section 112. According to the commenter, while section 112(d) does not explicitly grant the EPA the authority to establish such a program, the "measures, means or techniques" of section 110(a)(2)(A) include market mechanisms therefore it is reasonable for the EPA to interpret the "measures, processes, methods systems, or techniques' language of section 112(d)(2) to include them as well. The commenter states that this is especially true because of section 112(d)(2)'s grant of discretion to the EPA to choose an appropriate method for control.
Comment 27: Commenters 17880 and 18432 state that they strongly support the EPA's decision to not include a cap-and-trade program in the proposed rule. Commenters note that they also opposed the 2004 CAMR rule as it would have a disproportionate negative impact on communities close to power plants.
Comment 28: Commenters 17383 and 17689 note that the New Jersey court decision vacated the Clean Air Mercury Rule (CAMR) on procedural grounds. According to the commenters, the continuous application of existing Clean Air programs with the addition of a Section 111 program (e.g., the commenter suggest a cap and trade based program) aimed at Hg emissions would meet the requirements of the act in a more cost effective manner while guaranteeing health and environmental benefits substantially similar to that likely achieved under this proposal.
Response to Comments 26 - 28: The EPA is not establishing a trading program in lieu of CAA section 112(d) standards or as a beyond-the-floor control. The EPA maintains that it must regulate EGUs under CAA section 112(d) unless the agency delists such sources consistent with CAA section 112(c)(9)(B), and the facts do not support delisting of EGUs. See New Jersey v. EPA, 517 F.3d 574, 583 (D.C. Cir. 2008). Further, even if the EPA determined it had the authority to require a trading program as a beyond-the-floor option, the agency would still be required to consider whether the program was achievable considering the costs, non-air quality health and environmental impacts and energy requirements of such a program in order to impose it. The EPA does not have sufficient information to evaluate at this time whether the costs and other impacts of a trading program for the HAP emissions remaining after compliance with the MACT floor limits are reasonable.
The EPA is authorized to consider in the beyond-the-floor analysis alternative mechanisms for regulating HAP emissions to levels lower than those required by the MACT floor. But the EPA must establish the MACT floor based on the emissions limits achieved by the best performing source (for new sources) or sources (for existing sources) for each HAP or surrogate emitted by the source category.
4. Miscellaneous comments.
Comment 29: Commenter 17648 states that "no section of the Clean Air Act requires a benefit-cost analysis of rules under section 112 of the Clean Air Act." According to the commenter, it is legally impermissible to consider cost in establishing the MACT floor because by basing the floor on what is already achieved Congress has included legally permissible cost considerations in establishing MACT standards. Further, the commenter points out that while cost is a factor in the beyond-the-floor analysis, the consideration of that factor is limited to "cost-effectiveness" and not "benefit-cost."
Response to Comment 29: The EPA agrees that costs may not be considered in establish MACT floor limits pursuant to CAA section 112(d)(3), and that costs must be considered when evaluating whether standards should be beyond the floor pursuant to CAA section 112(d)(2).
Comment 30: Commenter 17732 states that, to the extent allowed by existing law, the EPA should implement emissions reductions under the NESHAP Rule on a regional basis, or in phases that take into categories of EGUs and regional rulemakings. In particular the commenter states that the rule should take into account the geographic and spatial differences between the western and eastern regions of the U.S. In addition the commenter notes that the western states are subject to Regional Haze glide path. According to the commenter, the agency must consider that few power plants in either region are as critical to the economies of their states as the FCPP and NGS are to the Navajo Nation economy, and the Navajo Nation, a sovereign government, which derives two thirds of its general operating revenue from coal mining.
Response to Comment 30: The EPA is authorized to provide up to 3 years to comply with NESHAP pursuant to CAA section 112(i)(3)(A). The agency has provided the maximum compliance period in the final rule. To the extent the EPA could provide for a regional approach, the approach would have to require sources to comply in less than 3 years in some regions and provide sources in the last region the full 3 years to comply. We need not determine whether this approach would be legal because the agency has provided the maximum available time for all sources. While the EPA cannot extend the compliance period in this rule, the agency is mindful of the importance of FCPP and NGS to the Navajo Nation and other Tribes that rely on those facilities, and we will work with the NGS and FCPP after the rule is promulgated to address any compliance related issues associated with complying with the final rule.
Comment 31: Commenter 17867 states that the EPA should consider the life of the plant when establishing the MACT standard.
Response to Comment 31: The EPA is unable to respond to this comment because the commenter has not provided a legal theory for considering plant age, and we do not believe plant age alone is a sufficient basis to subcategorize.
Comment 32: Commenter 17751 states that one alternative that was not considered was no regulation. According to the commenter, the no regulation alternative is supported by the fact that Hg emissions have been declining over time as a result of a variety of forces, including the effects of replacement of aging plants with new, cleaner ones, changes in the mix of fuels used for electricity generation, and the effects of previously implemented Federal and State regulations. The commenter states that this trend (reduction of emissions by 7.6% per year) suggests that by the year 2029, total EGU emissions of Hg will be only 9.4 tons per year  -  below the 10 ton annual threshold for a source group to be subject to the MACT provisions of the CAA. According to the commenter, without regulatory intervention, Hg emissions from the EGU sector will reach by 2034 the 6.8 tons per year target set by the proposed rule for 2016.
Comment 33: Commenter 19121 recognizes that due to the nation's long and proud history of advanced industrialization and power development, and the fact that most power plant sites are not as fortunately designed as the commenters' there have been concerns about health impact due to power plant-specific Hg emissions. According to the commenter, what is striking is that given the immense number of power plants in the U.S., lowering Hg from the power sector will lower the overall atmospheric Hg concentration by about 1%. Commenter believes this reflects that although NESHAPS will be effective, other regulatory methods would have been valuable and more timely.
Response to Comment 32 and 33: The EPA determined that it was appropriate and necessary to regulate HAP emissions from EGUs and added such units to the CAA section 112(c) list of sources subject to regulation under CAA section 112. Listed sources must be subjected to regulation under CAA section 112(d) unless the Agency delists such sources consistent with CAA section 112(c)(9)(B). See New Jersey v. EPA, 517 F.3d 574, 583 (D.C. Cir. 2008). As the EPA stated in the proposed and final rules, the agency's analyses indicate that EGUs do not satisfy the statutory requirements for delisting. Furthermore, we determined it was necessary to regulate HAP emissions from EGUs, in part, because implementation of the requirements of the CAA will not address the hazards to public health identified in our risk analysis. We are not sure how commenter estimated future Hg emissions from EGUs and we believe our estimates are reasonable based on the available information.
Comment 34: Commenter 17751 states that one alternative that was not considered regulation of just Hg. According to the commenter, as part of that analysis the EPA should estimate costs and benefits for limits that would achieve reduction of annual Hg emissions to a level just below 10 tons per year, because that is the threshold that, if already achieved, would exempt the EGU sector from the MACT provisions of the CAA. The commenter states that the agency should also examine the alternative of a regulation limiting only total PM to the levels proposed in the current rulemaking for the various categories of EGUs to determine whether achieving the forecast results in terms of PM2.5 reductions could be achieved at a lower cost alone than in concert with Hg reduction.
Response to Comment 34: The EPA determined that it was appropriate and necessary to regulate HAP emissions from EGUs and added such units to the CAA section 112(c) list of sources subject to regulation under CAA section 112. Listed sources must be subjected to regulation under CAA section 112(d) unless the agency delists such sources consistent with CAA section 112(c)(9)(B). See New Jersey v. EPA, 517 F.3d 574, 583 (D.C. Cir. 2008). As the EPA stated in the proposed and final rules, the agency's analyses indicate that EGUs do not satisfy the statutory requirements for delisting.
The EPA also must regulate EGUs under CAA section 112(d) and that provision requires the EPA to regulate all HAP emitted from EGUs. See CAA section 112(c)(2) (requiring listed sources be regulated pursuant to section 112(d)); see also Sierra Club v. EPA, 479 F.3d 875, 883(D.C. Cir. 2007) (finding that "EPA has a `clear statutory obligation to set emission standards for each listed HAP'").
Comment 35: Commenter 17851 states that the EPA's MACT floors for new sources are unlawful because although section 112(d) may allow new sources floors to be based on emission levels, those emission levels must be the product of control. According to the commenter, since Congress expressly changed the MACT floor benchmark for new sources from "emission levels" to "emission control," it is obvious that not only did they eschew emission levels as being the preferred benchmark, they wanted to ensure that whatever benchmark the EPA uses for new sources, it must be the product of control. As the agency knows, states the commenter, emission levels can be achieved by intentional control, unintentional control, or no control ("happenstance" as the agency often calls it). Thus, states the commenter, if the agency chooses to use emission levels as the benchmark for new source floors, it can only use those emission levels achieved in practice by control (whether it is intentional control, or as National Lime Association v. EPA, 233 F.3d 625 (D.C. Cir. 2000). The commenter states that consequently, establishing new source MACT floors by examining emission levels, without determining which ones were achieved by control, is unlawful. According to the commenter, since the EPA has not examined the emissions in its database to see if the emission levels are based on technological control, its proposed MACT floors for new sources are unlawful.
Response to Comment 35: The D.C. Circuit Court precedent is in conflict with commenter's assertion concerning the consideration of non-technology factors in establishing MACT floors. See Sierra Club v. EPA, 479 F.3d 875, 882-83 (D.C. Cir. 2007).
Comment 36: Commenter 18932 states that energy efficiency is an available resource that can facilitate timely compliance with the proposed rule. According to the commenter, the southeast states have an enormous untapped energy efficiency potential that would displace a significant amount of fossil-fuel-generated electricity. The commenter states that in a 2009 study, Professor Marilyn Brown and her colleagues at the Georgia Institute of Technology explained that the combination of heavy reliance on fossil-fuels and weak or totally lacking energy efficiency programs presents enormous energy efficiency potential in the southern U.S.
Commenter 18932 states that based on a review of 19 separate reports comprising more than 250 estimates of energy efficiency potential, the Georgia Tech study "conclude[d] that a reservoir of cost-effective energy savings exists in the South." According to the commenter, by exploiting readily available, cost-effective energy efficiency resources, southeast states "could largely offset the growth in energy consumption forecast for the region over the next decade" and reduce "energy consumption in 2020 down nine percent below projected levels, which would bring future consumption to slightly less than present levels...This would entirely offset the need to expand electricity generation capacity in the South through the year 2020."
The commenter states that Professor Brown and other experts at Georgia Tech and Duke University's Nicholas School have reaffirmed the potential for significant energy savings in this region in subsequent research. According to the commenter, a 2010 report describing in-depth primary research examined the impact of nine cost-effective energy efficiency policies and concluded that implementation of these policies would create a flat energy consumption trajectory over the next 20 years, representing a 16% decrease in energy consumption in 2030 as compared to the reference case (Marilyn Brown, et al., Energy Efficiency in the South, Southeast Energy Efficiency Alliance, at 124 (April 12, 2010), available at http://www.seealliance.org/se_efficiency_study/full_report_efficiency_in_the_south.pdf. See also Marilyn Brown, et. al., Myths and Facts about Energy in the U.S. South, Working Paper #51, Georgia Institute of Technology (July 2011), available at http://www.spp.gatech.edu/faculty/workingpapers/wp64.pdf (concluding that energy efficiency and renewable energy resources could entirely satisfy energy demand growth in the South)).
Commenter 18932 concludes that these findings support the EPA rule and the findings in the preamble that encourage deployment of energy efficiency-promoting strategies and initiatives to safeguard system reliability and, especially, to curb cost increases that might otherwise result from implementation of the Toxics Rule. According to the commenter, there are compelling legal and factual reasons to finalize and implement the Utility Air Toxics Rule according to the 3-year compliance schedule mandated by CAA section 112(d)(3)(A). The commenter states that the record also demonstrates that there is no justification warranting further delay in finalizing the rule and no justification for a compliance extension under CAA section 112(d)(3)(B) or a Presidential exemption under CAA section 112(d)(4).
Response to Comment 36: The EPA appreciates the support of the commenter.

1B - Legal aspects of Appropriate and Necessary Finding
Note: Many legal comments on the Appropriate and Necessary Finding are contained and addressed in the preamble to the final rule.
1. Interpretation of "appropriate and necessary."
Commenters: 17775, 18500, 17774, 17696, 17840, 18033, 17391, 17718, 17623, 17732, 17716, 17712, 17723, 17765, 17886, 19114, 17884, 18023, 19536/19537/19538
Comment 1: Commenter 18023 states that the EPA must give the terms "appropriate" and "necessary" their plain meaning under section 112(n)(1)(A) and not expand these terms simply to justify greater regulation.
Response to Comment 1: The EPA disagrees with the commenter's contention that the EPA's interpretation of the terms appropriate and necessary are not consistent with the plain meaning of section 112(n)(1)(A). We direct the commenter to the preambles to the proposed and final rules for the agency's rationale for its interpretation of the statute.
Comment 2: Commenter 17736 states that the EPA lacks the legal and factual support necessary to follow through with a rule regulating Hg and other HAP from EGUs under CAA section 112. According to the commenter, but for the EPA's improper interpretation of "appropriate and necessary" under section 112(n)(1)(A), the proposed rule would never have left the drawing board, deemed unjustified for incorporation into the scheme of CAA provisions already regulating this source category.
Response to Comment 2: The EPA disagrees with the commenter that the EPA's interpretation of the statute is flawed. We further reject the commenter's assertion that the agency lacked a factual basis for our appropriate and necessary determination that supports the regulation of EGUs under section 112. We provide a detailed discussion of the legal interpretation of the statute and the factual bases for our appropriate and necessary determination in the preambles to the proposed and final rules.
Comment 3: Several commenters (17696, 17774, 17775) state that the fact that coal-fired EGUs may be the largest, or near largest emitters, of certain acid HAP is irrelevant to the Appropriate and Necessary Finding under section 112(n)(1)(A). According to the commenters, the quantity of emissions seems to be a deciding factor for the EPA.
Response to Comment 3: The EPA determined that HAP emissions from EGUs pose a hazard to public health and the environment as explained in the preamble to the proposed rule and confirmed in this final action. For acid gas HAP, the EPA did note that EGUs are the largest emitters of HCl and other acid gas HAP and that such HAP contribute to already high atmospheric levels of other chronic respiratory toxicants and to environmental loading and degradation due to acidification. We reasonably concluded that EGUs' emissions of acid gas HAP contribute to health and environmental impacts based on this fact.
Comment 4: Several commenters (17840, 18033, 17931, 17718) state that the EPA's interpretation of the term "appropriate" is so broad that it renders the entire analytical exercise required by Congress utterly meaningless. Commenters agree that the EPA has the discretion to define the contours of the inquiry within the bounds of reasonableness but claim the EPA is ignoring the fact that throughout this process the agency has maintained that "[s]ection 112(n)(1)(A) therefore sets an important and unique condition precedent for regulating Utility Units under section 112..." According to the commenters, the EPA has not heeded this Congressional direction in the proposed rule as its interpretation of "appropriate" effectively overrides the primary congressional command to analyze "hazards to public health reasonably anticipated to occur" from EGUs.
Response to Comment 4: The EPA disagrees with the commenters' assertion that our interpretation of section 112(n)(1) is inconsistent with the statute for all the reasons set forth in the preambles to proposed rule and this final action. We also disagree that the fact that section 112(n)(1)(A) creates a unique condition precedent to listing and regulating EGUs under section 112 in any way undermines our interpretation of that provision. To the extent the commenters are relying on interpretations of the statute set forth in the 2005 action, that reliance is misplaced as we have provided a reasoned basis for revising our interpretation of the statute.
Comment 5: Commenters 17623 and 18500 state that when evaluating the "necessary" prong of section 112(n)(1)(A) the EPA should focus on national impacts. According to the commenters, when Congress intended for the agency to address international air pollution issues, it clearly specified a process and procedure for doing so (see CAA Section 115).
Response to Comment 5: In the preamble to the proposed rule, the EPA indicated that we may find it necessary to regulate EGUs if we determine that our ability to argue effectively for global reductions in Hg emissions will be impaired without such regulation. 76 FR 24490 and 25018. Nothing in section 112(n)(1) or section 115 prohibits such a consideration and the commenters have not explained how it does. In any case, the EPA stated in the preamble to the proposed rule that there were several independent determinations that supported the necessary finding, including the conclusion that imposition of the requirements of the CAA will not address the identified hazards to public health posed by HAP emissions from EGUs. The necessary finding is consistent with the EPA's interpretation as set forth in the preamble to the proposed rule and we maintain that interpretation of section 112(n)(1)(A) is reasonable for the reasons stated in the preambles to proposed rule and this final action.
Comment 6: Commenter 18500 states there is no authority under CAA section 112 to support regulation based on the EPA's statement that the regulation will make "the market for electricity in the U.S. . . . more level and no longer skewed in favor of higher polluting units."
Response to Comment 6: The EPA's Appropriate and Necessary Finding in the preamble to the proposed rule is fully supported for the reasons set forth therein and in this final action. The EPA also did not state that it was appropriate and necessary to regulate EGUs to make the market for electricity more level and not skewed toward higher polluting units. Instead, the EPA indicated that one result of the final rule would be that all EGUs would be required to control their emissions to the same level and that will mean that the currently skewed electricity market will no longer favor higher emitters that can pollute without paying the costs of control. This factual statement in no way undermines our finding that it is appropriate and necessary to regulate EGUs under CAA section 112.
Comment 7: Commenters 17731 and 17716 state that the EPA's stated objectives of forcing older EGUs into retirement and taking advantage of co-benefits are not objectives of CAA section 112(n)(1).
Response to Comment 7: The EPA did not state as the commenters allege that the objectives of the final rule are to force older EGUs into retirement or take advantage of co-benefits of EGUs under CAA section 112. The commenter is confusing the likely results of the final rule with the basis for the final rule.
Comment 8: Commenter 17886 states that the total tons of HAP emissions are not relevant to the "appropriate and necessary" determination. The commenter states that that the "nub of the inquiry" should be health consequences.
Response to Comment 8: The EPA agrees that the hazards to public health are a central consideration for evaluating whether it is appropriate and necessary to regulate EGUs under CAA section 112. We also maintain that adverse environmental effects may be considered. We are confused by the commenter's assertion that total amount of HAP is not relevant to the appropriate and necessary determination, however, because we evaluate the hazards to public health and the environment based on the HAP emissions from EGUs. For acid gas HAP, we determined that the volume of such HAP from EGUs poses a hazard to the environment because they contribute to the acidification of the environment. We maintain that conclusion is supported by the record. In any case, there were multiple independent bases in support of the appropriate finding, including findings associated with the hazards to public health posed by HAP emissions from EGUs.
Comment 9: Commenter 17931 states that in order to ensure that EGUs are regulated under CAA section 112 thereby leveling the market for electricity, the EPA's "necessary" interpretation is so narrow that it precludes consideration of the many measures under the CAA that have proven to effectively reduce Hg and HAP emissions in this country. According to the commenter, this overly narrow interpretation prevents the ability to tailor its regulation of EGUs by investigating other viable regulatory programs on a cost-benefit basis.
Response to Comment 9: The EPA disagrees with the commenter. The EPA determined that HAP emissions from EGUs pose a hazard to public health and the environment that will not be addressed through imposition of the requirements of the CAA. As explained in the preambles to the proposed rule and this final action, the EPA is not required to scour the CAA to find alternative mechanisms for regulating HAP emissions from EGUs in the necessary analysis. Congress provided CAA section 112 for the purpose of regulating HAP emissions from stationary sources and we are reasonably using that authority in this case.
Comment 10: Commenter 19114 states that the EPA has turned the statutory language on its head, claiming that the undefined terms in the statute both vest it with broad discretion to exercise its regulatory authority, and are so prescriptive that they compel the regulatory results set forth in this proposed rule. According to the commenter, the EPA cannot have it both ways.
Response to Comment 10: The EPA disagrees with the commenter that our interpretation of the statute is in error for the reasons set forth in the preambles to the proposed rule and this final action.
Comment 11: Several commenters (19536, 19537, 19538) state that there is no statutory support for any suggestion that Congress meant to require the EPA to make specific health-based or risk-based findings before determining that it was "appropriate and necessary" to regulate HAP emissions from EGUs under CAA section 112(d)(2) and (3). According to the commenters, other sections of the CAA and other provisions in CAA section 112 do contain such health- and risk-based language as a regulatory (or deregulatory) predicate, and it is instructive that the key final sentence of CAA section 112(n)(1)(A) lacks any such language.
Response to Comment 11: The EPA maintains that its interpretation of CAA section 112(n)(1) is reasonable for the reasons stated in the preambles to the proposed rule and this final action. We need not address whether the EPA could find it appropriate and necessary absent a finding that HAP emissions from EGUs pose a hazard to public health or the environment that will not be addressed through imposition of the requirements of the CAA because we made such a finding in 2000 and confirmed that finding in this action.
Comment 12: Several commenters (19536, 19537, 19538) state that because EGUs are the largest emitters of several HAP that pose hazards to the public health and environment, it would be unreasonable to determine that regulation is not necessary. According the commenters, the meaning of the term "necessary" can only be determined by looking at the context of the term. With respect to CAA section 112(n)(1)(A), this was added in 1990 when Congress was "unhappy with the pace" of the EPA's efforts to secure large scale reductions of HAP. The commenters note that when Congress employs capacious and judgment-laden language like "appropriate and necessary," it is surely within the EPA's discretion and authority to conclude that it is reasonable and justified to regulate HAP emissions from the single largest industrial source of those toxic emissions
Response to Comment 12: The EPA agrees that it has considerable discretion to determine whether it is appropriate and necessary to regulate HAP emissions from EGUs and we maintain we have reasonably exercised that discretion through our interpretation of the statute and our Appropriate and Necessary Finding as explained in the preambles to the proposed rule and this final action.
Comment 13: Commenter 17712 states that the EPA has not met the CAA section 112(n)(1)(A) necessary and appropriate requisites to listing EGUs under CAA section 112(c). According to the commenter, the New Jersey decision never ruled on the appropriateness of the EPA listing including whether it met the procedural and substantive requirements under CAA section 307. The commenter asserts that to date the EPA has not adequately explained it's interpretation of appropriate and necessary in the context of CAA section 112(n)(1)(a) and listing under CAA section 112(c), unless it is contending that a mere "plausible link" between all man-made mercury emissions and methylmercury (MeHg) in fish makes it appropriate and necessary to regulate EGU emissions under CAA section 112. The commenter notes that the EPA's interpretation of CAA section 112(n)(1)(A) in this proposal is almost completely opposite its interpretation in the 2005 final rule and would render that subparagraph a meaningless addition to CAA section 112. According to the commenter, the EPA repeatedly takes the position that no language in CAA section 112(n)(1)(a) prevents it from interpreting the subparagraph in the manner that nullifies any special meaning to the appropriate and necessary requisites to CAA section 112 EGU HAP regulation. The commenter states that CAA section 112(n) was added to address EGU emissions is a unique manner as compared to the other provisions of CAA section 112. No other language in CAA section 112 references the regulation of a source category of emissions if "appropriate and necessary." The commenter states that as the EPA pointed out in its 2005 rule, its 2000 listing decision did not provide an interpretation of appropriate but instead focused on "facts and circumstances" of EGU emissions themselves. According to the commenter, this 2011 proposal, then, is the EPA's first attempt to explain how it finds it appropriate and necessary to regulate EGU emissions under CAA section 112.
Response to Comment 13: The EPA disagrees with the commenter. We established our interpretation of CAA section 112(n)(1) in the preamble to the proposed rule, and we are not revising that interpretation in this final action except as discussed in the preamble to the final rule. We have fully addressed this comment in the preamble to the proposed rule and response to comments contained in the preamble to the final rule.
Comment 14: Commenter 17723 states that the availability of controls does not justify a finding of appropriate and necessary. According to the commenter, if public health concerns provide an inadequate impetus for HAP regulations, the EPA turned to the availability of controls as a justification to find it was appropriate and necessary to regulate EGUs under CAA section 112.
Response to Comment 14: The EPA did not rely on the availability of controls as an independent basis for regulating HAP emissions from EGUs. The EPA maintains that the availability of controls supports the finding, however, because CAA section 112(n)(1) provides evidence that Congress considered such availability relevant to the agency's determination, as we explained in the preambles to the proposed rule and this final action.
Comment 15: Commenter 17765 states that the EPA has not properly analyzed or satisfied the regulatory prerequisite required pursuant to CAA section 112(n)(1)(A) for regulating Hg and other HAP under a maximum achievable control technology (MACT) standard and therefore lacks the necessary regulatory foundation for doing so in this proposed rule.
Response to Comment 15: The EPA disagrees with the commenter. We maintain that the 2000 finding was valid at the time it was made based on the information available to the agency and we confirmed that it remains appropriate and necessary to regulate EGUs based on our new analyses, as explained in the preambles to the proposed rule and this final action.
Comment 16: Commenter 17686 states that, citing the New Jersey decision, the EPA contends that it has properly listed EGUs under section 112(c) and that EGU HAP emissions do not meet requirements of section 112(c)(9) for delisting. The commenter states that the EPA misreads the court's decision and that the New Jersey court never ruled on the appropriateness of the EPA listing including whether it met the procedural and substantive requirements under section 307. According to the commenter, the EPA must show that it is appropriate and necessary to regulate EGU emissions following the requirements in section 112(n)(1)(A). The commenter states that the EPA has never adequately explained its interpretation of appropriate and necessary in the context of section 112(n)(1)(A) and listing under section 112(c), unless it is contending that a mere "plausible link" between all manmade mercury emissions and MeHg in fish makes it appropriate and necessary to regulate EGU emissions under section 112.
Commenter 17686 states that the EPA's re-interpretation of section 112(n)(1)(A) in this proposal is almost completely opposite its interpretation in the 2005 final rule, and this reinterpretation would render that subparagraph a meaningless addition to section 112. The commenter states that throughout this 2011 proposal, the EPA repeatedly takes the position that no language in section 112(n)(1)(A) prevents it from interpreting the subparagraph in the manner that nullifies any special meaning to the appropriate and necessary requisites to section 112 EGU HAPs regulation. According to the commenter, it is clear that section 112(n) was added to address EGU emissions in a unique manner as compared to the other provisions of section 112; no other language in section 112 references the regulation of a source category of emissions if "appropriate and necessary." As the EPA pointed out in its 2005 rule, states the commenter, its 2000 listing decision did not provide an interpretation of appropriate but instead focused on "facts and circumstances" of EGU emissions themselves. According to the commenter, this 2011 proposal, then, is the EPA's first attempt to explain how the EPA finds it appropriate and necessary to regulate EGU emissions under section 112. The commenter states that there are numerous flaws in this attempt.
The commenter further asserts that the EPA has sought to lump all HAP emissions from sources in addition to EGU emissions when determining whether it is appropriate and necessary to regulate EGU emissions. According to the commenter, section 112(n)(1)(A) specifically references hazardous of utility emissions, not all emissions as the EPA does here. The commenter states that in the 2005 final rule, the EPA assessed the health effects of EGU Hg emissions and found no appreciable health risk. For this 2011 proposal, states the commenter, the EPA evaluates health risk based on total worldwide Hg inventory. According to the commenter, evaluating individual source category emissions under the all worldwide emissions approach, however, means that all sources of any particular HAP no matter how small the relative contribution are subject to section 112 regulation in the EPA's view. The commenter states that this position is logically not sustainable, and, additionally, the EPA includes environmental effects in addition to health hazards in its determination, even though section 112(n)(1)(A) "necessary and appropriate" requirement is directed exclusively at EGU emission health hazards.
Response to Comment 16: The EPA disagrees with the commenter and directs attention to the preambles to the proposed rule and this final action for the factual and legal basis for this final rule and responses to these comments.
In addition, the commenter incorrectly interprets the methods and conclusions of the Hg Risk TSD. The EPA used two risk metrics to identify watersheds with populations potentially at risk due to U.S. EGU-attributable Hg deposition: (1) watersheds where Hg deposition from U.S. EGUs alone exceeds to reference dose (RfD) for MeHg (MeHg), and (2) watersheds where total Hg deposition exceeds the RfD and U.S. EGUs contribute at least 5% of that deposition. The first metric reflects public health hazards caused by U.S. EGUs, and the second metric reflects the fact that any contribution of Hg to watersheds where potential exposures to MeHg exceed the RfD poses a public health hazard and U.S. EGUs contribute to that hazard. In addition, the non-Hg inhalation risk case studies identified cancer risk exceeding 1 in a million at several facilities based on HAP emissions from U.S. EGUs alone. The results of these risk analyses confirm that it remains appropriate and necessary to regulate U.S. EGUs under CAA section 112.
2. Consideration of both public health and environmental effects.
Commenters: 17383, 17608, 17648, 17681, 17716, 17731, 17775, 17798, 17834, 17855, 17877, 18033, 18502, 19114, 19536/19537/19538, 18023
a. Commenters supporting the EPA's interpretation that CAA section 112(n)(1) allows consideration of both public health and environmental effects.
Comment 17: Commenter 17648 states that EPA properly considered both health and environmental effects in determining that it is appropriate to regulate EGUs. According to the commenter, the health hazard derives directly from the deposition of Hg emissions from EGUs into the environment where it is converted to MeHg and bioaccumulates in fish through the food chain. The commenter states that humans who consume fish with elevated Hg levels are exposed to the risks attendant to such elevated concentrations, and any interpretation excluding consideration of environmental effects would be absurd.
Comment 18: Commenter 17648 agrees with the EPA with respect to evaluating whether HAP emissions from EGUs have environmental effects. The commenter states that the agency appropriately measures the impact in light of the statutory definition of "adverse environmental effect" in CAA section 112(a)(7). According to the commenter, that definition reflects clear Congressional intent to allow the agency to consider a wide range of effects, noting that it includes "any" enumerated effect "which may reasonably be anticipated." The commenter states that Congress reinforced this intent in requiring the EPA to consider additional standards within 8 years of promulgation of standards under CAA section 112(d), both to assure "an ample margin of safety to protect public health" and to prevent an "adverse environmental effect." See 42 U.S.C. CAA section 7412(f)(2)(A).
Comment 19: Several commenters (19536, 19537, 19538) state that the EPA correctly interprets CAA section 112(n)(1)(A) to allow consideration of environmental effects in making an Appropriate and Necessary Finding. According to commenters, although CAA section 112 certainly allows the agency to find regulating EGUs is appropriate and necessary based on health or environmental findings, it does not require a "hazard" finding at all. Rather, state the commenters, it simply provides that the EPA must regulate EGUs if, after "considering" the Utility Study, it finds that doing so is appropriate and necessary; thus, it leaves the agency broad discretion to make the appropriate and necessary finding so long as the agency has reasonably "consider[ed]" the results of the study. According to the commenters, the agency could have reasonably concluded that Congress wanted emissions of all listed HAP reduced by the maximum achievable degree, and thus regulation of EGUs which are the most significant emitter of virtually every HAP listed in CAA section 112(b) is both appropriate and necessary regardless of whether it was possible for the agency to fully assess all of the risks that toxic emissions from EGUs present.
Comment 20: Several commenters (19536, 19537, 19538) state where the CAA provides that EPA's action must be "based on" a study -- more limiting language than the "considering" language found in CAA section 112(n) -- the agency is not required to base its action exclusively on that study unless Congress has expressly stated so. See Sierra Club v. EPA, 325 F.3d374, 377 (D.C. Cir. 2003) (holding that CAA section 202(l) of the CAA -- which requires the EPA to conduct a "study of the need for, and feasibility of, controlling emissions of toxic air pollutants" and then requires the EPA to promulgate standards for mobile source air toxics "based on" that study -- does not require that the standards be based exclusively on the required study).
Comment 21: Several commenters (19536, 19537, 19538) state that nowhere in CAA section 112(n)(1)(A) or elsewhere has Congress expressly stated, or even implied, that the EPA must base its Appropriate and Necessary Finding exclusively upon the study prescribed in the first sentence of that CAA section. Moreover, state the commenters, the HAP emitted by EGUs are associated with adverse environmental impacts on wildlife, including endangered species, and ecosystem health. According to the commenters, the body of scientific evidence referenced in the preamble to the proposed rule clearly supports the agency's assessment and information provided by the commenter build on that scientific knowledge.
Comment 22: Several commenters (19536, 19537, 19538) state that the EPA's reliance on environmental effects as additional support for the finding that it is appropriate to regulate EGUs is supported by the rest of CAA section 112, which contains many examples of language evincing Congressional concern about the adverse environmental effects of HAP. For example, state the commenters, the EPA can add a substance to the list of HAP based solely on its adverse environmental effects. 42 U.S.C. CAA section 7412(b)(2) - (3) (authorizing the EPA to add a pollutant to the CAA section 112(b) list based on "a threat of adverse human health effects...or adverse environmental effects..."). Furthermore, state the commenters, an industry may be listed as containing major sources, and sources within that industry thus made subject to MACT regulation, based solely on HAP that have adverse effects on the environment. See id. CAA section 7412(b)(2).
Comment 23: Several commenters (19536, 19537, 19538) state that it would be unreasonable to assume that Congress required the EPA to conduct an assessment of Hg's environmental effects under CAA section 112(n)(1)(B), but at the same time forbid the agency from considering these effects in its subsequent decision-making process.
Response to Comments 17 - 23: The EPA agrees with commenters that the Appropriate and Necessary Finding may be based on a finding that HAP emissions pose a hazard to public health or the environment. The EPA also agrees that it may consider information other than the Utility Study in making the appropriate and necessary determination. We further agree that it is reasonable to look to the definition of "adverse environmental effect" and the delisting criteria for guidance on determining whether HAP emissions from EGUs pose a hazard to public health or the environment.
b. Commenters disagreeing with the EPA's interpretation that 112(n)(1) allows consideration of both public health and environmental effects.
Comment 24: Several commenters (17716, 17731, 18803) state that the EPA erred by including environmental effects in the "appropriate" deliberations. These commenters do not agree with the EPA's position that "inclusion of environmental effects in CAA section 112(n)(1)(B) indicates Congress' interest in protecting the environment from HAP emissions." Id. at 24988/2. According to the commenters, the inclusion of "environmental effects" in subparagraph (b) of CAA section 112(n)(1) does not show an intent to incorporate by reference the same term "effects" in other subparagraphs. To the contrary, state the commenters, when a term is included in one part of statute, but excluded in a different part, it is assumed Congress intended a differentiation. E.g., Russello v. United States, 464 U.S. 16, 23 (1983) ("`[W]here Congress includes particular language in one CAA section of a statute but omits it in another CAA section of the same Act, it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion.'") The commenters note that given that the disparate language is found in two subparagraphs of the same CAA section, the presumption is especially strong here.
Response to Comment 24: The EPA disagrees with the commenters for the reasons set forth in the preambles to the proposed rule and in this final action. Further, we do not think Russello in any way undermines our interpretation of CAA section 112(n)(1). Commenters have not explained why our interpretation of CAA section 112(n)(1) should be analogized to the statutory provisions of Organized Crime Control Act at issue in Russello, and we do not believe the comparison is reasonable or that the holding in that case is applicable to our interpretation of section 112(n)(1).
Comment 25: Commenter 17716 also states that further evidence of Congress' intended disparate treatment is found in the CAA section (n)(1)(B) limitation of considering environmental effects only of Hg emissions while under CAA section (n)(1)(A) all HAP emissions are to be studied.
Response to Comment 25: The EPA disagrees with commenter's characterization of the statute as limiting the Agency to only considering hazards to public health, and we direct attention to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 26: Commenters 17716 and 18502 disagree with the EPA's statement that CAA section 112(n)(1)(A) "is not written in a manner to preclude consideration of other information when determining whether it is appropriate and necessary to regulate EGUs under CAA section 112, and that includes consideration of all hazards, both health and environmental, posed by HAP emitted by EGUs," 76 FR 29488/3. According to the commenters, this position relies on the proposition that "`based upon' does not mean `solely.'" The commenters note that the term "Based on" is not found in CAA section (n)(1)(A), thereby undercutting the proposition. The actual language of (n)(1)(A) refers to a finding made "after considering the results of the study required by this subparagraph." According to the commenters, the referenced study results did not include any environmental effects, demonstrating that they were not to be considered in the "appropriate" finding.
Response to Comment 26: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 27: Commenter 17775 states that where Congress expected the EPA to take account of environmental effects in regulating under CAA section112, it said so explicitly on the face of the statute. According to the commenter, in CAA section 112(n) Congress required that the EPA (i) "assess the hazards to public health and the environment resulting from the emission of hydrogen sulfide associated with the extraction of oil and natural gas resources;" and (ii) "study...the potential hazards of hydrofluoric acid...in industrial and commercial applications to public health and the environment." See CAA section 112(n)(5), (6).
Response to Comment 27: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. Further, we disagree with commenter's implication that Congress did not specifically require consideration of environmental effects as evidenced by CAA section 112(n)(1)(B).
Comment 28: Commenters 17775 and 18023 state that the EPA has inherent discretion to consider "other information" that the agency may have derived from sources other than the Utility Study, including the Mercury Study and NAS Study in making the "appropriate and necessary" finding. However, commenters state that the information that can be considered is limited to "hazards to public health" that are "reasonably anticipated to occur as a result of emissions by EGUs."
Response to Comment 28: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 29: Commenters 17775 and 18023 do not believe that the EPA explains how the language in subparagraph (n)(1)(B) to "consider the...environmental effects" of emissions from both EGUs and other sources authorizes the EPA to consider "environmental effects," and the effects of HAP emissions from non-EGU sources, in making its "appropriate and necessary" finding under subparagraph (n)(1)(A). According to the commenters, it is contrary to congressional intent to construe the provisions of subparagraphs (n)(1)(A), (B), and (C) to provide in their totality a framework for the Agency's determination of whether to regulate HAP emissions from EGUs under CAA section 112.
Response to Comment 29: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 30: Commenter 18023 states that the EPA's interpretation allowing environmental impacts to be considered "flip-flops and rejects its 2004 interpretation" of the same provision. According to the commenter, by the EPA's logic they could consider any factors not expressly excluded from its consideration by Congress. The commenter notes that prior attempts to find statutory authority for such consideration absent an expressed congressional prohibition have been rejected by the courts and cites as an example Ethyl v. EPA, wherein the court stated, "To suggest, as the [agency] effectively does, that Chevron step two is implicated any time a statute does not expressly negate the existence of a claimed administrative power..., is both flatly unfaithful to the principles of administrative law...and refuted by precedent." Ethyl Corp. v. EPA, 51 F.3d1053, 1060 (D.C. Cir. 1995).
Response to Comment 30: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 31: Several commenters (17383, 17798, 17877, 17885, 17681) state that the CAA section 112(n)(1)(A) "necessary and appropriate" requirement is directed exclusively at EGU emission health hazards.
Response to Comment 31: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 32: Commenter 17608 states that the EPA's interpretations of the statute on the meaning of "appropriate" are inconsistent and unnecessarily limit the EPA's statutory discretion. According to the commenter, the EPA argues that silence should be interpreted as a prohibition but then states that the term "appropriate" is extremely broad and nothing in the statute suggests that the agency should ignore environmental effects in determining whether to regulate EGUs under CAA section 112.
Response to Comment 32: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 33: Commenters 17731 and 18033 state the timing created by Congress in establishing the structure of CAA section 112(n)(1) shows an intent to base an "appropriate" finding solely on the hazards to the public health data that would have existed at the time the determination was to have been completed. The commenters state that the Utility Study ((n)(l)(A)) and the NAS Study ((n)(l)(C)) both were to be completed "within 3 years after November 15, 1990," and neither refers to environmental effects. In contrast, state the commenters, the Mercury Study ((n)(l)(B)) was to be completed "no later than 4 years after November 15, 1990" and was to consider environmental effects. According to the commenters, had the Utility Study and the NAS Study been completed in a timely fashion, neither would have had any environmental effects data. Consequently, such data would not have become available until a year later with the issuance of the Mercury Study. According to the commenters, Congress intended that the Administrator make an "appropriate" finding under (n)(l)(A) concurrently with issuance of the Utility Study and the NAS Study, or a year before any environmental effects data were available for consideration.
Response to Comment 33: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. In addition, we note that Congress did not provide a time limit on the appropriate and necessary determination as commenters suggest, except that the agency was constrained to wait until after the Utility Study was issued and considered. The CAA provided the agency the authority to make the appropriate and necessary determination based on the Utility Study alone if the facts warranted such action, and it also provided the agency with the flexibility to wait and consider all the information generated pursuant to CAA section 112(n)(1) and elsewhere if the agency determined it was appropriate to consider additional information. In fact, the EPA completed the Mercury Study prior to completing the Utility Study, notwithstanding the statutory mandates.
Comment 34: Commenter 17731 states that the EPA's view that if "Congress intended to prohibit EPA from considering adverse environmental effects in the `appropriate' finding, it would have stated so expressly" stands administrative law on its head. According to the commenter, "EPA's view that it has inherent power to act unless Congress prohibits such action contravenes the fundamental principle that agencies are statutory creatures whose only powers are those expressly delegated by Congress." E.g., Louisiana PSC v. FCC, 476 U.S. 355, 374 (1986) ("an agency literally has no power to act...unless and until Congress confers power on it"); Bowen v. Georgetown Univ. Hospital, 488 U.S. 204, 208 (1988) (same).
Response to Comment 34: The EPA disagrees with the commenter's conclusion as it relates to the EPA's interpretation of CAA section 112(n)(1) and we note that we did not determine it was reasonable to consider adverse environmental effects based only on the statement cited above by commenter. 76 FR 24988. We maintain that our interpretation of the statute is proper for the reasons set forth in the preambles to the proposed rule and this final action.
Comment 35: Several commenters (17731, 17716, 17834) state that the EPA takes inconsistent positions regarding how the statute should be interpreted. The commenters state that on one hand the EPA contends that the limited reference to "environmental effects of such [i.e., mercury] emissions" in (n)(l)(B) can be transformed into a general requirement that environmental effects of all HAP emissions can be considered under the (n)(l)(A) "appropriate" finding, while on the other hand, the EPA contends that costs cannot be considered in making that finding because "nowhere in CAA section 112(n)(l) does Congress require the consideration of costs in assessing health and environmental impacts. The commenters state that the only reference to costs is in CAA section 112(n)(l)(B) and that reference required the agency to consider the costs of emission reduction controls for Hg." 76 Fed Reg. at 24987. According to the commenters, the only reference to "environmental effects" is in CAA section 112(n)(l)(B), and that reference requires the EPA to consider those effects only for Hg. Thus, the EPA's explanation does not justify treating costs one way (excluded) and environmental effects another way (included).
Comment 36: Commenter 17834 states that the EPA utilizes an illogical approach to the "appropriate and necessary" determination. On the same page of the proposed rule, states the commenter, the EPA first reasons that, with respect to CAA section 112(n)(1)(A), the absence of language expressly precluding the consideration of environmental effects provides the EPA with discretion to take such effects into account; however, the absence of language expressly authorizing the consideration of costs prohibits the EPA from taking costs into account. Regarding both environmental effects and costs, the EPA draws its authority, or lack thereof, from 112(n)(1)(B).
Response to Comments 35 and 36: Commenters are correct that CAA section 112(n)(1)(B) references both environmental effects and costs of controls, but we maintain it was reasonable to consider adverse environmental effects and not costs in determining whether it is appropriate and necessary to regulate HAP emissions from EGUs under CAA section 112. The agency is not required to and does not consider costs in any listing decisions and we maintain that approach is consistent with the purpose of CAA section 112. Congress also did not authorize the agency to consider costs in any delisting decisions. On the other hand, protection of the environment is a goal of the CAA generally and CAA section 112 specifically, see CAA section 112(a)(7) ("defining adverse environmental effects"), such that it would be unreasonable to ignore environmental hazards associated with HAP emissions from EGUs when assessing whether to regulate EGUs under CAA section 112. Congress also specifically called for the EPA to assess environmental impacts in deciding whether to delist source categories and thus it is reasonable to consider such impacts in assessing whether to regulate EGUs under CAA section 112. Commenters do not and cannot state that the agency must consider costs in determining whether regulation of EGUs under CAA section 112 is appropriate and necessary, especially where, as here, hazards to public health and the environment are at issue.
Thus, although the EPA could have interpreted the term "appropriate" to allow for the consideration of costs, it reasonably declined to do so. Its approach is wholly consistent with the structure of CAA section 112, which does not contemplate consideration of costs in either listing or delisting decisions. Moreover, once listed, Congress precluded the agency from considering cost in setting MACT floors, which are technology-based standards. It is hard to imagine that Congress wanted the agency to consider costs in assessing whether to regulate EGUs, but then to ignore such costs in setting emission standards. We continue to believe that had Congress sought to require the consideration of costs in CAA section 112(n)(1)(A), it would have so stated.
Comment 37: Commenter 18033 states that the EPA's invocation of the U.S. Supreme Court's decision in Massachusetts v. EPA for the proposition that even if the benefits of regulating are negligible, the EPA still must promulgate standards under CAA section 112 is inapposite of the facts at issue in this rulemaking. According to the commenter, whereas in Massachusetts the Supreme Court rejected the EPA's use of "policy considerations" as a shield to deny a rulemaking petition urging the agency to regulate GHG emissions from new automobiles, the agency in this setting is attempting to use the very same "policy considerations" as a sword for regulating HAP emissions from EGUs. In rejecting the EPA's then-position, states the commenter, the Court emphasized that the agency may not rest its decision to regulate or not to regulate on "reasoning divorced from the statutory text."
Response to Comment 37: The EPA disagrees with the commenter's assertion that the agency does not have a reasoned basis under CAA section 112(n)(1) for regulating HAP emissions from EGUs. We maintain that the 2000 finding was reasonable at the time it was made based on the information available and our recent analyses confirm that it remains appropriate and necessary to regulate HAP emissions from EGUs.
Further, the agency cited Massachusetts v. EPA in relation to the necessary prong of the finding as support for our conclusion that we may find it necessary to regulate EGUs under CAA section 112 even if such regulation will not fully resolve the identified hazards. 76 FR 24991. Commenter has not explained why the EPA was wrong to rely on Massachusetts v. EPA for support of that proposition.
3. Impacts of EGUs alone or with other sources in Appropriate Finding.
Commenters: 17383, 17623, 17648, 17712, 17774, 17799, 17834, 17877, 17885, 18425, 18443, 19114, 19536/19537/19538, 18023
a. Comments generally supporting the EPA's approach looking at EGUs along with other sources in deciding "appropriate."
Comment 38: Commenter 17648 supports the EPA's interpretation that limiting consideration solely to the impact of emissions from EGUs without considering the cumulative impacts of other sources is unfounded. According to the commenter, nothing in CAA section 112(n)(1) specifically constrains the EPA to assessing whether only the emissions from EGUs independently present a risk to human health and the environment, and neither does CAA section 112(n)(1) evince any intent to restrict the agency from considering whether HAP emissions from EGUs, when combined with other HAP emissions, present a risk to public health and the environment.
Comment 39: Commenter 18425 states that the EPA was correct in considering the results of the Mercury Study and the NAS study when making its determination. The commenter states that the EPA was also correct in considering risks of HAP in terms of emissions from EGUs alone or in conjunction with other sources. According to the commenter, the text of the CAA does not require causation as the basis for an appropriate and necessary determination. Therefore, states the commenter, it is appropriate to list EGUs for regulation even though they may not be the only source of these HAP and that regulating EGU emissions alone will not end the threat posed to public health from HAP. Consequently, the commenter supports the EPA's determination to list EGUs for regulation under CAA section 112 even though there may be other sources of HAP contributing to current levels in the atmosphere.
Comment 40: Several commenters (19536, 19537, 19538) support the EPA's interpretation that CAA section 112(n)(1)(A) allows for an "appropriate and necessary" finding regardless of whether the hazard posed to public health or the environment results from either HAP emissions from EGUs alone or the harm is in conjunction with HAP emissions from other sources. According to one commenter, the EPA's 2004 finding that the statute limits consideration "solely on whether the utility HAP emissions themselves are posing a hazard to public health" (70 FR 15,998) is unreasonable and "inconsistent with case law, as well as a misuse of the science." The commenter states that "the remainder of CAA section 112 confirms that Congress did not intend any industrial category to avoid regulation because EPA might not have exacting proof of the harm caused by that category in isolation." The commenter provides three specific reasons for this conclusion. First, the commenter notes that it would be "highly unlikely that Congress would have required EPA to conduct an assessment [under 112(n)(1)(B)] of the cumulative effects of these various source categories, but then prohibited that assessment from being considered in any decisions regarding regulation of one of them." Second, the phrase "result of emissions," used in CAA section 112(n)(1)(A), is also found in CAA section 112(k)(3)(B) with respect to developing a national strategy for area source HAP emissions. Interpreting that language, states the commenter, the EPA has said that determining which HAP pose the greatest threat to human health "as the result of emission from area sources," does not require that "such threats must be exclusively the result of emissions from area sources." See National Air Toxics Program: The Integrated Urban Strategy, 64 Fed. Reg. 38,706, 38,716 (July 19, 1999). Finally, the commenter notes that CAA section 112(c)(3) requires that the EPA list for regulation sufficient source categories so that, in the aggregate, ninety percent of emissions for the thirty most hazardous air pollutants are regulated. 42 U.S.C. CAA section 7412(c)(3). According to the commenter, this requirement illustrates that Congress was aware that the cumulative emissions from different industries have cumulative adverse effects on public health and the environment.
Response to Comments 38 - 40: The EPA agrees that the statute authorizes consideration of HAP emissions from EGU in conjunction with HAP emissions from other sources when evaluating whether HAP emissions from EGUs pose a hazard to public health for the reasons set forth in the preambles to the proposed rule and in this final action.
b. Comments generally disagreeing with the EPA's approach of looking beyond just EGUs in evaluating whether it is "appropriate" to regulate EGUs.
Comment 41: Commenter 17623 states that under the "appropriate" prong of CAA section 112(n)(1)(A), the statute does not specifically authorize the EPA to make its determination based on sources of HAP emissions other than EGUs and that regulation of EGUs would be "most legally defensible" if the determination was based only on HAP from the EGU source category. According to the commenter, looking at HAP emissions beyond the source category does not fit with the EPA's approach of considering the availability of controls to address HAP emissions from EGUs, which is one of the justifications the EPA provides for regulating EGUs under CAA section112.
Response to Comment 41: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. Further, we are unsure why our consideration of the availability of controls conflicts with a determination that HAP emissions from EGUs and other sources should be considered. In any case, the availability of controls was not an independent basis for regulating EGUs under CAA section 112.
Comment 42: Commenter 18023 states that the EPA's conclusion that "nothing in CAA section 112(n)(1)(A) prohibits consideration of HAP emissions from EGUs in conjunction with HAP emissions from other sources of HAP," 76 FR 24,989, is inconsistent with basic rules of statutory construction and the court's Ethyl v. EPA decision. See Ethyl Corp., 51 F.3d at 1060. According to the commenter, the EPA cannot rely on informational studies commissioned by Congress elsewhere under the CAA to broaden the scope if this particular regulatory mandate.
Response to Comment 42: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 43: Several commenters (17834, 19114, 17774, 17799, 18443) state that the plain language of CAA section 112(n)(1)(A) only allows for the consideration of emissions by EGU and not in conjunction with other emission sources. According to the commenters, the EPA's determination to include multiple sources is arbitrary, capricious and otherwise not in accordance with law.
Response to Comment 43: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 44: Several commenters (17383, 17712, 17885, 17877) state that CAA section 112(n)(l)(A) specifically references hazardous utility emissions, not all emissions. According to the commenters, under the EPA's total worldwide Hg inventory approach means all sources of any particular HAP no matter how small the relative contribution are subject to CAA section 112 regulation.
Response to Comment 44: The EPA disagrees with the commenters. We direct commenters to the preamble to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. We also do not understand the commenters' conclusion that the Appropriate and Necessary Finding for EGUs affects other source categories. We do not believe that this finding affects our regulation of other sources categories.
4. Finding for all HAP to be regulated.
Commenters: 17608, 17623, 17648, 17681, 17771, 17799, 17840, 17855, 17864, 17868, 17871, 17886, 17931, 18033, 18421, 19114, 18443, 19536/19537/19538, 18023
a. Comments generally agreeing with the EPA's interpretation that once the EPA makes the determination that it is appropriate and necessary to regulate HAP emissions from EGUs and lists EGUs pursuant to CAA section 112(c), all HAP emitted by EGUs must be regulated under CAA section 112.
Comment 45: Commenter 17648 states that once the EPA makes the determination that it is appropriate and necessary to regulate HAP emissions from EGUs, all HAP emitted by EGUs must be regulated under CAA section112. According to the commenter, the EPA is not required to make a separate 112(n)(1) determination for each HAP emitted by EGUs. The commenter states that the statute provides unambiguously that the EPA must promulgate emission standards for each of the HAPs listed for regulation. Nat'l Lime Ass'n, 233 F.3d at 633-34. According to the commenter, neither statutory text, legislative history, nor case law supports a position that CAA section 112(n)(1) exempts EGUs from this requirement applicable to other source categories listed for regulation under CAA section 112(c); CAA section 112(n)(1) simply requires various studies of HAP emissions from utility units, and includes the requirement that the EPA "shall regulate electric utility steam generating units under this CAA section, if the Administrator finds such regulation is appropriate and necessary after considering the results of the study required by this subparagraph." 42 U.S.C. CAA section 7412(n)(1)(A). According to the commenter, in requiring that EGUs be regulated "under this CAA section," Congress expressed its clear intention that EGUs be regulated under CAA section 112, not under subparagraph (A) of CAA section 112(n)(1).
Comment 46: Several commenters (19536, 19537, 19538) state that MACT standards must be adopted for all HAP emitted by a listed source category. The commenters further note that it would not be arbitrary and capricious had the EPA determined it was appropriate and necessary to list EGUs based upon Hg emissions alone, considering that the Congressionally established, performance-based approach of CAA section 112 has proven effective in reducing Hg and all other HAP from other industrial source categories; EGUs are the largest remaining uncontrolled sources of industrial Hg emissions in the country; and other statutory programs are less suited toward reducing Hg emissions than CAA section 112(d).
Comment 47: Several commenters (19536, 19537, 19538) state that there is no statutory support for any of the suggestions "sometimes advanced by utility industry representatives" that (1) Congress considered the same listed HAP less harmful and less worthy of regulation from power plants than from other industrial sectors emitting far less of those HAP than EGUs; (2) Congress wished the EPA to return to the discredited, abandoned risk-based approach that existed prior to the 1990 amendments, or to apply that approach just to EGUs; or (3) the Administrator's determination that MACT regulation of EGUs is appropriate and necessary could not be based (in part) upon the appropriateness of treating the power sector equitably and similarly relative to other industrial sectors covered by MACT; upon the appropriateness of maintaining uniform regulatory treatment of HAP emissions from EGUs under CAA section 112(d)(2) and (3); and upon the appropriateness of applying the proven, performance-based HAP reduction approach of CAA sections 112(d)(2) and (3) to EGUs.
Comment 48: Commenter 18421 states that they support the EPA's decision to regulate the source category based on emissions of a single HAP. According to the commenter, making an "appropriate" determination on the basis of a source category's emissions of a single HAP rests on a reasonable interpretation of the Act. CAA sections 112(c)(1) and (2) respectively require the Administrator to list and regulate "major sources...of [HAP]," which are defined as sources emitting 10 tons per year or more of even a single HAP. Further the commenter notes that CAA section 112(c)(9) contemplates the addition of a source category to the CAA section 112(c) list because of its emissions of a single air pollutant.

Response to Comments 45 - 48: The EPA appreciates the support. We agree that our interpretation of CAA section 112(n)(1) as set forth in the preambles to the proposed rule and this final action is consistent with the statute and supports the regulation of all HAP from EGUs.
b. Comments generally disagreeing with the EPA's interpretation that once the EPA makes the determination that it is appropriate and necessary to regulate HAP emissions from EGUs and lists EGUs pursuant to CAA section 112(c), all HAP emitted by EGUs must be regulated under CAA section 112.
Comment 49: Commenter 17623 disagrees with the EPA's interpretation that the statute and judicial precedent require regulation of all HAP emitted by a major source listed pursuant to CAA section 112(c) of the CAA, referred to as the "in for one, in for all" requirement. According to the commenter, this is not the only interpretation that the EPA could adopt. The commenter's interpretation is that unlike other categories of HAP sources, Congress treated EGUs differently. Under this interpretation, states the commenter, it would be appropriate for the EPA to exercise its regulatory discretion if the agency determines that the HAP emitted by EGUs do not pose a hazard to human health. The commenter states that the EPA already made the determination in the 2000 Finding that regulation of HAP emissions from coal and oil-fired EGUs under CAA section 112 is "appropriate and necessary" due to Hg emissions and that other HAP may pose a potential concern to public health and emissions of these substances "may be evaluated further during the regulatory process." 65 Fed. Reg. 79,825, 79,827 (Dec. 20, 2000). According to the commenter, CAA section 112(n)(1)(A) does not require the EPA to set MACT standards for all HAP emissions from EGUs because at the point of the original listing the EPA made no regulatory finding that these additional HAP posed a risk to public health.
Response to Comment 49: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. In addition, we disagree that the 2000 finding was limited to a finding that only Hg emissions from EGUs pose a hazard to public health and the environment, and the new analyses confirming it remains appropriate and necessary do not focus only on Hg emissions. In addition, the commenter appears to take the position that the EPA should assume that HAP emissions from EGUs do not pose a hazard to public health or the environment unless the agency makes a finding that specific HAP emissions from EGUs do pose a hazard to public health and the environment. The lack of an affirmative finding should not be interpreted as finding of no hazard to public health or the environment. EGUs are a listed source category and the EPA has regulated the category consistent with the requirements of the CAA and case law interpreting the establishment of standards for regulating listed source categories.
Comment 50: Commenter 17871 states that there are no grounds in either the law or the record before the agency for requiring regulation of all HAP emitted by area sources. Contrary to assertions made by the EPA in the preamble to the proposed rule, states the commenter, an "appropriate and necessary" finding for one HAP does not authorize the EPA to regulate all HAP emitted by EGUs. 76 FR 24,988. Rather, states the commenter, it militates in favor of a more narrow focus on only those particular HAP that the EPA finds-after consideration of existing CAA controls-are a hazard to public health. According to the commenter, the EPA acknowledges that the holding in National Lime is limited to "major sources" of HAP, 76 FR 24,989, and does not support a position that all HAP emitted from area source EGUs should be regulated.
Response to Comment 50: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. In addition, Congress defined EGUs in CAA section 112(a)(8) in a manner that includes both major and area sources and we maintain it is reasonable to regulate the source category consistent with that definition. Nothing in the CAA prohibits the EPA from regulating major and area source EGUs together.
Comment 51: Commenter 18443 states that the EPA's conclusion that it must set emission standards that address all HAP is legally incorrect. According to the commenter, EGUs are treated uniquely and CAA section 112(n)(1)(A) requires the EPA Administrator to decide if regulation is appropriate and necessary. According to the commenter, in December 2000, the EPA Administrator found that regulation of coal- and oil-fired EGUs was appropriate and necessary under CAA section 112 and proceeded to list those units under CAA section 112(c), but the EPA's 2000 regulatory determination only gave it authority to set MACT limits for Hg emissions from EGUs. The commenter further notes that in the 2004 proposed rule the EPA went to great lengths to explain why it only had legal authority to set Hg MACT limits for coal-fired EGUs. According to the commenter, the EPA has offered no explanation or legal analysis for its abrupt shift in its interpretation of its legal authority to regulate HAP emissions from EGUs under CAA section 112.
Response to Comment 51: The EPA disagrees with the commenter. The agency did explain why it was regulating all HAP from EGUs, and we direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 52: Commenter 17608 strongly supports the EPA's previous interpretations of CAA section 112 to allow for only control of Hg emissions. The commenter disagrees with the EPA's argument that it is legally obligated to establish MACT floors for all HAP. According to the commenter, in order to avoid requiring substantial resources to be devoted to non-Hg emissions without a benefit to public health or the environment, an "appropriate and necessary" finding should be required for each HAP before regulating EGUs for that HAP under CAA section 112. The commenter notes that the EPA's reliance on Sierra Club v. EPA (479 F.3d 875, 883 (D.C. Cir. 2007)) is distinguishable because in Sierra Club the agency already had the authority to regulate under CAA section 112 without the "appropriate and necessary" finding.
Response to Comment 52: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. We also disagree with commenter that there is no health or environmental benefit to regulating non-Hg HAP. We also disagree that we stated we were legally obligated to set MACT standards for all HAP from area sources; however, we exercised our discretion to regulate both major and area sources together consistent with the statutory definition of EGU in CAA section 112(a)(8). Concerning Sierra Club, commenter has not explained why CAA section the 112(n)(1)(A) listing provision excuses the EPA from complying with the D.C. Circuit's interpretation of the CAA section 112(d) standards setting provisions.
Comment 53: Commenters 17771 and 19114 state that the EPA exceeded its authority in proposing emissions standards for non-Hg HAP. According to the commenters, the EPA's own analysis did not find that it was "appropriate or necessary" to regulate emissions of all HAP.
Response to Comment 53: The EPA disagrees with the commenters. We direct commenters to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 54: Commenter 17799 states that an affirmative finding for Hg does not automatically trigger regulation of non-Hg HAP. The commenter states that the EPA's interpretation of the CAA as requiring control of all HAP from power plants regardless of the health hazard they might or might not pose would read these phrases out of the statute. According to the commenter, this would be unreasonable under established rules of statutory construction where Courts "are obliged to give effect, if possible, to every word Congress used." Reiter v. Sonotone Corp., 442 U.S. 330, 339 (1979).
Response to Comment 54: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. Commenter has not explained how the EPA failed to give meaning to all of CAA section 112(n)(1). Nothing in that provision requires the EPA to make an independent finding for individual HAP before finding that it is appropriate and necessary to regulate EGUs under CAA section 112, nor does the statute require or authorize the EPA to regulate only those HAP from EGUs once the source category is listed under CAA section 112(c).
Comment 55: Commenter 17868 states that the utility study and the related Great Lakes Study along with an assessment of CAA section 303(d) waterbody segments listing of noncompliant waterbodies in the Clean Water Act justified only Hg reduction through the MACT program. According to the commenter, the utility study did not justify proposed MACTs for non-Hg metals or acid gases.
Response to Comment 55: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment. In addition, we are unclear how the Great Lakes Study and 303(d) of the Clean Water Act affect our decision to regulate all HAP from EGUs after the source category is listed.
Comment 56: Several commenters (17840, 17855, 17931, 18803) state that the EPA has not performed the necessary analysis for any other non-Hg HAP it is proposing to regulate. According to the commenters, the EPA mistakenly believes it is obligated to regulate all HAP "if the Agency determines that the emissions of one or more HAP emitted from EGUs pose an identified or potential hazard to public health or the environment at the time the finding is made." 76 FR 24987.
Response to Comment 56: The EPA disagrees with the commenters. We direct commenters to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 57: Commenter 17864 states that CAA section 112(n)(1)(A) and CAA section 307(d)(1)(C) together require that the EPA go through notice and comment rulemaking to determine whether it is "appropriate and necessary" to regulate EGUs under CAA section 112, and require that this determination be based on the Final Report to Congress. According to the commenter, the EPA lacks the authority to promulgate a final rule that regulates HAP not indentified in the Final Report.
Response to Comment 57: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 58: Commenter 18033 states that the EPA's reliance on National Lime, 233 F.3d 625 (D.C. Cir. 2000) to support proposed regulation of "all HAP" is "unavailing" because that case turned on the language of CAA section 112(d)(1) rather than the sub-CAA section at issue in this rulemaking.
Response to Comment 58: The EPA disagrees with the commenter. We direct the commenter to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
Comment 59: Commenters 17681 and 17886 state that the EPA's conclusion that it can regulate all HAP based on a finding for a single HAP is contrary to the CAA.
Response to Comment 59: The EPA disagrees with the commenters. We direct commenters to the proposed rule and responses to comments in the preamble to the final rule for responses to this comment.
c. Comments disagreeing with the regulation of acid gases or other non-Hg HAP.