Protection of Visibility: Amendments to Requirements for State Plans

Federal RegisterJan 10, 2017

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 51 and 52

[EPA-HQ-OAR-2015-0531; FRL-9957-05-OAR]

RIN 2060-AS55

Protection of Visibility: Amendments to Requirements for State Plans

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

The Environmental Protection Agency (EPA) is finalizing revisions to requirements under the Clean Air Act (CAA) for state plans for protection of visibility in mandatory Class I Federal areas in order to continue steady environmental progress while addressing administrative aspects of the program. In summary, the revisions clarify the relationship between long-term strategies and reasonable progress goals (RPGs) in state implementation plans (SIPs) and the long-term strategy obligation of all states; clarify and modify the requirements for periodic comprehensive revisions of SIPs; modify the set of days used to track progress towards natural visibility conditions to account for events such as wildfires; provide states with additional flexibility to address impacts on visibility from anthropogenic sources outside the United States (U.S.) and from certain types of prescribed fires; modify certain requirements related to the timing and form of progress reports; and update, simplify and extend to all states the provisions for reasonably attributable visibility impairment, while revoking most existing reasonably attributable visibility impairment federal implementation plans (FIPs). The EPA also is making a one-time adjustment to the due date for the next periodic comprehensive SIP revisions by extending the existing deadline of July 31, 2018, to July 31, 2021.

DATES:

This final rule is effective on January 10, 2017.

ADDRESSES:

The EPA established Docket ID No. EPA-HQ-OAR-2015-0531 for this action. All documents in the docket are listed in the

http://www.regulations.gov

Web site. Although listed in the index, some information is not publicly available,

e.g.,

Confidential Business Information or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy. Publicly available docket materials are available electronically in

http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

For general information regarding this rule, contact Mr. Christopher Werner, Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, by phone at (919) 541-5133 or by email at

werner.christopher@epa.gov;

or Ms. Rhea Jones, Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, by phone at (919) 541-2940 or by email at

jones.rhea@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Preamble Glossary of Terms and Acronyms

The following are abbreviations of terms used in this document.

AQRV Air quality related value

BART Best available retrofit technology

ext

Light extinction

CAA Clean Air Act

CFR Code of Federal Regulations

EGU Electric generating unit

EPA Environmental Protection Agency

FIP Federal implementation plan

FLM or FLMs Federal Land Manager or Managers

ICR Information collection request

IMPROVE Interagency monitoring of protected visual environments

NAAQS National Ambient Air Quality Standards

NSR New Source Review

Nitrogen oxides

OMB Office of Management and Budget

PM Particulate matter

2.5

Particulate matter equal to or less than 2.5 microns in diameter (fine particulate matter)

Particulate matter equal to or less than 10 microns in diameter

PRA Paperwork Reduction Act

RHR Regional Haze Rule

RPG Reasonable progress goal

RPO Regional planning organization

SIP State implementation plan

Sulfur dioxide

TAR Tribal Authority Rule

URP Uniform rate of progress

B. Entities Affected by This Rule

Entities potentially affected directly by this rule include state, local and tribal

governments, as well as FLMs responsible for protection of visibility in mandatory Class I federal areas.

Entities potentially affected indirectly by this rule include owners and operators of sources that emit particulate matter equal to or less than 10 microns in diameter (PM

), particulate matter equal to or less than 2.5 microns in diameter (PM

2.5

or fine PM), sulfur dioxide (SO

), oxides of nitrogen (NO

), volatile organic compounds and other pollutants that may cause or contribute to visibility impairment. Others potentially affected indirectly by this rule include members of the general public who live, work or recreate in mandatory Class I areas affected by visibility impairment. Because emission sources that contribute to visibility impairment in Class I areas also may contribute to air pollution in other areas, members of the general public may also be affected by this rulemaking.

The EPA's visibility protection regulations may apply, as appropriate under the Tribal Authority Rule (TAR) in 40 CFR part 49, to an Indian tribe that receives a determination of eligibility for treatment as a state for purposes of administering a tribal visibility protection program under section 169A of the CAA. No tribe has applied for such status, and so at present the EPA is responsible for implementation of the visibility protection regulations in areas of tribal authority. This responsibility includes, but is not limited to, implementation of the reasonable progress requirements of 40 CFR 51.308(f), as necessary or appropriate. These rule changes may impact the development and approvability of tribal implementation plans that tribes may wish to submit in the future. We encourage states to provide outreach and engage in discussions with tribes about their regional haze SIPs as they are being developed.

Areas designated as mandatory Class I Federal areas consist of national parks exceeding 6,000 acres, wilderness areas and national memorial parks exceeding 5,000 acres, and all international parks that were in existence on August 7, 1977. CAA section 162(a). In accordance with section 169A of the CAA, the EPA, in consultation with the Department of Interior, promulgated a list of 156 areas where visibility is identified as an important value. 44 FR 69122 (November 30, 1979). The extent of a mandatory Class I area includes subsequent changes in boundaries, such as park expansions. CAA section 162(a). Although states and tribes may designate as Class I additional areas that they consider to have visibility as an important value, the requirements of the visibility program set forth in section 169A of the CAA apply only to “mandatory Class I Federal areas.” Each mandatory Class I Federal area is the responsibility of a “Federal Land Manager.” CAA section 302(i). When we use the term “Class I area” in this action, we mean any one of the 156 “mandatory Class I Federal areas” where visibility has been identified as an important value, unless the context makes it clear that additional non-mandatory Federal Class I areas are also meant to be included.

C. Obtaining a Copy of This Document and Other Related Information

In addition to being available in the docket, an electronic copy of this

Federal Register

document will be posted at

http://www.epa.gov/visibility.

A “track changes” version of the full regulatory text that incorporates and shows the full context of the changes in this final action is also available in the docket for this rulemaking. In addition to the final and regulatory text documents, other relevant documents are located in the docket, including technical support documents referenced in this preamble.

D. Judicial Review

Under CAA section 307(b)(1), judicial review of this final action is available only by filing a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit by March 13, 2017. Under CAA section 307(d)(7)(B), any such judicial review is limited to only those objections that were raised with reasonable specificity in timely comments. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality of this action for purposes of judicial review, extend the time in which a petition for judicial review may be filed, or postpone the effectiveness of the rule. Under CAA section 307(b)(2), the requirements established by this final rule may not be challenged separately in any civil or criminal proceedings brought by the EPA to enforce the requirements.

E. Organization of This

Federal Register

Document

The information presented in this document is organized as follows:

I. General Information

A. Preamble Glossary of Terms and Acronyms

B. Entities Affected by This Rule

C. Obtaining a Copy of This Document and Other Related Information

D. Judicial Review

E. Organization of This

Federal Register

Document

F. Background on This Rulemaking

II. Executive Summary

III. Overview of Visibility Protection Statutory Authority, Regulation and Implementation

A. Visibility in Mandatory Class I Federal Areas

B. Reasonably Attributable Visibility Impairment

C. Regional Haze

D. Air Permitting

IV. Final Rule Revisions

A. Ongoing Litigation in

Texas

EPA

B. Cooperative Federalism

C. Clarifications To Reflect the EPA's Long-Standing Interpretation of the Relationship Between Long-Term Strategies and Reasonable Progress Goals

D. Other Clarifications and Changes to Requirements for Periodic Comprehensive Revisions of Implementation Plans

E. Changes to Definitions and Terminology Related to How Days Are Selected for Tracking Progress

F. Impacts on Visibility From Anthropogenic Sources Outside the U.S.

G. Impacts on Visibility From Wildland Fires

H. Clarification of and Changes to the Required Content of Progress Reports

I. Changes to Reasonably Attributable Visibility Impairment Provisions

J. Consistency Revisions Related to Permitting of New and Modified Major Sources

K. Changes to FLM Consultation Requirements

L. Extension of Next Regional Haze SIP Deadline From 2018 to 2021

M. Changes to Scheduling of Regional Haze Progress Reports

N. Changes to the Requirement That Regional Haze Progress Reports be SIP Revisions

O. Changes to Requirements Related to the Grand Canyon Visibility Transport Commission

V. Environmental Justice Considerations

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act (PRA)

C. Regulatory Flexibility Act (RFA)

D. Unfunded Mandates Reform Act (UMRA)

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

K. Congressional Review Act (CRA)

VII. Statutory Authority

F. Background on This Rulemaking

On May 4, 2016, the EPA proposed revisions to the 1999 Regional Haze Rule (RHR),

which include clarifications and modifications to the requirements that states (and, if applicable, tribes) have to meet as they implement programs for the protection of visibility in mandatory Class I Federal areas, under sections 169A and 169B of the CAA. The EPA held public hearings on May 19, 2016, in Washington, DC and on June 1, 2016, in Denver, Colorado. States, industry, private citizens and non-governmental organizations submitted over 180,000 comments. Based on EPA's review of the comments, we are finalizing most of the proposed revisions, but are also making some changes to respond to the concerns raised by commenters. These include: Changes to the proposed terminology used to refer to emissions inventories; changes to the proposed definitions and terminology related to how days are selected for tracking progress; changes to the proposed fire-related definitions and terminology; changes to the proposed required content of progress reports; changes to the proposed deadline for a state response to a reasonably attributable visibility impairment certification; the addition of a requirement for FLMs to consult with states prior to making a reasonably attributable visibility impairment certification; and minor changes to the requirements for FLM consultation on SIPs and progress reports. The EPA is issuing this final rule under section 307(d) of the CAA. Section 553(d) of the Administrative Procedure Act (APA), 5 U.S.C. Chapter 5, generally provides that rules may not take effect earlier than 30 days after they are published in the

Federal Register

. CAA section 307(d)(1) clarifies that: “The provisions of section 553 through 557 * * * of Title 5 shall not, except as expressly provided in this section, apply to actions to which this subsection applies.” Thus, section 553(d) of the APA does not apply to this rule. The EPA has nevertheless considered the purposes underlying APA section 553(d) in making this rule effective upon publication. The primary purpose of the 30-day waiting period prescribed in section 553(d) is to give affected parties a reasonable time to adjust their behavior and prepare before the final rule takes effect. Notably, there are no specific obligations in the first thirty days of this regulatory action, and all obligations are established as of a date certain, rather than being tied to the effective date.

Here and elsewhere in this document, the terms “Regional Haze Rule,” “1999 Regional Haze Rule” and “1999 RHR” refer to the 1999 final rule (64 FR 35714), as amended in 2005 (70 FR 39156, July 6, 2005), 2006 (71 FR 60631, October 13, 2006) and 2012 (77 FR 33656, June 7, 2012).

In addition, section 553(d) allows an effective date less than 30 days after publication for a rule that “grants or recognizes an exemption or relieves a restriction.” An important aspect of this rule is the 3-year extension for state planning obligations. This extension is comparable to the grant of an exemption or relief from a restriction because it provides more time for states to meet a regulatory requirement. It is thus reasonable to make this action effective upon publication because states do not require an additional 30 days to adjust their behavior and prepare for the rule going into effect, and in fact will gain additional time to meet their planning obligations.

II. Executive Summary

The CAA's visibility protection program, implemented through the rules at 40 CFR 51.300 through 51.309, helps to protect clear views in national parks, such as Grand Canyon National Park, and wilderness areas, such as the Okefenokee National Wildlife Refuge.

Vistas in these areas are often obscured by visibility-impairing pollutants caused by emissions from numerous sources located over a wide geographic area. States are required to submit periodic plans demonstrating how they have and will continue to make progress towards achieving their visibility improvement goals. The first state plans were due in 2007 and covered the 2008-2018 planning period.

The EPA is making changes to the requirements that states (and, if applicable, tribes) have to meet for the second and subsequent implementation periods as they develop programs for the protection of visibility in mandatory Class I areas, consistent with CAA requirements. Implementation of the EPA's RHR (during the first implementation period) resulted in significant reductions in emissions and associated improvements in visibility in many Class I areas (

see

Section III.B of this document). This final rule supports continued environmental progress by retaining much of the 1999 RHR, clarifying or revising certain provisions of the visibility protection rules in 40 CFR part 51, subpart P, and removing rule provisions that have been superseded by subsequent developments. An overview of the revisions is provided later, with additional details throughout this document.

The EPA is clarifying the relationship between long-term strategies and RPGs in state plans and the long-term strategy obligations of all states. We are re-iterating that the CAA requires states to consider the four statutory factors (costs of compliance, time necessary for compliance, energy and non-air quality environmental impacts and remaining useful life) in each implementation period to determine the rate of progress towards natural visibility conditions that is reasonable for each Class I area. The rate of progress in some Class I areas may be meeting or exceeding the uniform rate of progress (URP) that would lead to natural visibility conditions by 2064, but this does not excuse states from conducting the required analysis and determining whether additional progress would be reasonable based on the four factors. The EPA is revising the RHR to address a number of issues, as discussed in the proposal, including: The way in which a set of days during each year is to be selected for purposes of tracking progress towards natural visibility conditions; aspects of the requirements for the content of progress reports; updating, simplifying and extending to all states the provisions for reasonably attributable visibility impairment and revoking FIPs adopted in the 1980s that require the EPA to assess and address any existing reasonably attributable visibility impairment situations in some states; and revising the requirement for states to consult with FLMs. Other changes address administrative aspects of the program in order to reduce unnecessary burden. These include the following: The EPA is finalizing a one-time adjustment to the due date for the next SIPs (from 2018 to 2021); revising the due dates for progress reports; and changing the requirement that progress reports be submitted as formal SIP revisions to documents that need not comply with the procedural requirements of 40 CFR 51.102, 40 CFR 51.103 and Appendix V to Part 51—Criteria for Determining the Completeness of Plan Submissions. All of these changes apply to periodic comprehensive state implementation plans developed for the second and subsequent implementation periods and to progress reports submitted subsequent to those plans. These changes do not affect the development and review of state plans for the first implementation period or the first progress reports due under the 1999 RHR.

The rationale for these changes is described more fully in the descriptions of each change detailed later in this action as well as in the preamble to the proposed rule.

The revisions being finalized are informed by approximately 15 years of implementation of the CAA, numerous outreach sessions and stakeholder feedback regarding the regional haze program, and the many constructive comments we received on the proposal. The clarifications regarding the relationship between RPGs, long-term strategies and the long-term strategy obligation of all states are intended to ensure appropriate and consistent understanding of these requirements as states prepare their plans for the second implementation period. These clarifications reflect EPA's long-standing interpretation of the RHR, and are now being codified. The rule revisions related to how days are selected for visibility progress tracking will provide the public and state officials more meaningful information on how existing and potential new emission reduction measures are contributing or could contribute to reasonable progress in reducing man-made visibility impairment. Changes to FLM consultation requirements will help ensure that the expertise and perspective of these officials are brought into the state plan development process early enough that they can meaningfully contribute to the state's deliberations. Collectively, the changes being finalized now will ensure that the regional haze program is implemented consistent with CAA obligations, and ensure successful implementation during the second planning period and beyond.

81 FR 26942 (May 4, 2016).

With regard to the extension of the deadline of July 31, 2018, to July 31, 2021, for states' comprehensive SIP revisions for the second implementation period, this one-time change will benefit states by allowing them to obtain and take into account information on the effects of a number of other regulatory programs that will be impacting sources over the next several years. The change will also allow states to develop SIP revisions for the second implementation period that are more integrated with state planning for these other programs, an advantage that was widely confirmed in early discussions with states and in comments submitted to the docket for this rulemaking. We anticipate that this change will result in greater environmental progress than if planning for these multiple programs were not as well integrated. The end date for the second implementation period remains 2028, as was required by the 1999 RHR. Other than the one-time change to the next due date for periodic comprehensive SIP revisions, no change is being made for due dates for future periodic comprehensive SIP revisions.

The changes related to progress reports are intended to make the timing of progress reports more useful as mid-course reviews, to clarify the required content of progress reports for aspects on which there has been some confusion, and to allow states to conserve their administrative resources and make submission of progress reports more timely by removing the requirement that they be submitted as formal SIP revisions. We are retaining a requirement that states consult with FLMs on their progress reports, and that states offer the public an opportunity to comment on progress reports before they are finalized, which are two of the steps that applied to progress reports when they were required to be SIP revisions, and which will help ensure ongoing accountability for progress reports. Please note that while the proposed rule included identical FLM consultation periods for progress reports and periodic comprehensive SIP revisions, FLM consultation requirements for SIP revisions and progress reports will differ going forward. This issue is described more fully in Section IV.K of this document.

Finally, the 1999 RHR's provisions related to reasonably attributable visibility impairment required a recurring process of assessment and planning by the states. Experience since these provisions were promulgated suggests that situations involving reasonably attributable visibility impairment occur infrequently and therefore that an “as needed” approach for initiating a state planning obligation would be a more efficient use of resources. The EPA is finalizing its proposal to replace the recurring process of assessment of reasonably attributable visibility impairment with an as-needed approach. The change to an as-needed approach only applies to reasonably attributable visibility impairment—periodic planning for purposes of regional haze will continue. In addition, in light of our increased understanding of the interstate nature of visibility impairment, we are expanding the applicability of the requirement to address reasonably attributable visibility impairment from only states with Class I areas to all states. If a situation exists or arises in which a source or a small number of sources in a state without any Class I area causes reasonably attributable visibility impairment at a Class I area in another state, this mechanism will ensure adequate visibility protection.

III. Overview of Visibility Protection Statutory Authority, Regulation and Implementation

A. Visibility in Mandatory Class I Federal Areas

Reduction in visibility caused by emissions of PM

, PM

2.5

(

e.g.,

sulfates, nitrates, organic carbon, elemental carbon and soil dust) and their precursors (

e.g.,

, NO

and, in some cases, ammonia and volatile organic compounds) can take the form of either visibly distinct layers or plumes of pollution or more uniform “regional haze.” Fine particle precursors react in the atmosphere to form PM

2.5

, which along with directly emitted PM

and PM

2.5

impairs visibility by scattering and absorbing light. This light scattering reduces the clarity, color and visible distance that one can see. Particulate matter can also cause serious health effects in humans (including premature death, heart attacks, irregular heartbeat, aggravated asthma, decreased lung function and increased respiratory symptoms) and contribute to environmental effects such as acid deposition and eutrophication.

Data from the existing visibility monitoring network, the “Interagency Monitoring of Protected Visual Environments” (IMPROVE) monitoring network, show that at the time the RHR was finalized in 1999, visibility impairment caused by air pollution occurred virtually all the time at most national park and wilderness areas. The formally defined average visual range

in many Class I areas in the western U.S. was 62-93 miles. In some Class I areas, these visual ranges may have been impacted by natural wildfire and dust episodes in addition to anthropogenic impacts. In most of the eastern Class I areas of the U.S., the average visual range was less than 19 miles.

Visual range is the greatest distance, in kilometers or miles, at which a certain dark object can be discerned against the sky by a typical observer under certain defined conditions. Visual range defined in this highly controlled manner is inversely proportional to light extinction (b

ext

) by particles and gases and is calculated as: Visual Range = 3.91/b

ext

(Bennett, M.G., The physical conditions controlling visibility through the atmosphere; Quarterly Journal of the Royal Meteorological Society, 1930, 56, 1-29). Light extinction has units of inverse distance (

i.e.,

−1

or inverse Megameters (mega = 10

)). Under conditions other than those defined in this reference, people's ability to discern landscape features may vary and be different than implied by the value of the visual range as calculated from light extinction using this formula.

64 FR 35715 (July 1, 1999).

Based on visibility data through 2014, the visual range has increased 10 to 20 miles (4 to 7 deciviews)

since the year 2000 in eastern Class I areas on the 20 percent haziest days. Some western Class I areas have also experienced visual range increases of 5 to 10 miles (1 to 4 deciviews) on the 20 percent haziest days. However, in some areas, such as Sawtooth Wilderness area in Idaho, improvements from reduced emissions from man-made sources have been overwhelmed by impacts from wildfire and/or dust events. There are also some western areas where visibility has improved only by a slight amount or made no progress.

The deciview haze index (discussed in more detail in Section III.B.3 of this document) is logarithmically related to light extinction and is used by the regional haze program because it describes uniform differences in visibility across a range of visibility conditions.

B. Reasonably Attributable Visibility Impairment

In section 169A of the 1977 Amendments to the CAA, Congress enacted a program for protecting visibility in the nation's national parks, wilderness areas and other Class I areas due to their “great scenic importance.”

Section 169A(a) of the CAA establishes as a national goal the “prevention of any future, and the remedying of any existing, impairment of visibility in mandatory Class I Federal areas which impairment results from manmade air pollution.”

H.R. Rep. No. 294, 95th Cong. 1st Sess. at 205 (1977).

In 1980, the EPA promulgated regulations to address visibility impairment in Class I areas, including but not limited to impairment that is “reasonably attributable” to a single source or small group of sources,

i.e.,

“reasonably attributable visibility impairment.”

These regulations, codified at 40 CFR 51.300 through 51.307, represented the first phase in addressing visibility impairment from existing sources. They also addressed potential visibility impacts from new and modified major sources already subject to permitting requirements for purposes of protection of the National Ambient Air Quality Standards (NAAQS) and preventing significant deterioration of air quality.

45 FR 80084 (December 2, 1980).

Notably, not all states were subject to the 1980 reasonably attributable visibility impairment requirements. Under the 1980 rules, the 35 states and one territory (Virgin Islands) containing Class I areas were required to submit SIPs addressing reasonably attributable visibility impairment. The 1980 rules required states to (1) develop, adopt, implement and evaluate long-term strategies for making reasonable progress toward remedying existing and preventing future impairment in the mandatory Class I areas through their SIP revisions; (2) adopt certain measures to assess potential visibility impacts due to new or modified major stationary sources, including measures to notify FLMs of proposed new source permit applications, and to consider visibility analyses conducted by FLMs in their new source permitting decisions; (3) conduct visibility monitoring in mandatory Class I areas, and (4) revise their SIPs at 3-year intervals to assure reasonable progress toward the national visibility goal. In addition, the 1980 regulations provided that an FLM may certify to a state at any time that visibility impairment at a Class I area is reasonably attributable to a single source or a small number of sources. Following such a certification by an FLM, a state was required to address the requirements for best available retrofit technology (BART) for BART-eligible sources considered to be contributing to reasonably attributable visibility impairment. Also, the appropriate control of any source certified by an FLM, whether BART-eligible or not, would be specifically addressed in the long-term strategy for making reasonable progress toward the national goal of natural visibility conditions.

See

the

1980 rule's version of 40 CFR 51.302(c)(2)(i).

In practice, the 1980 rules resulted in few SIPs being submitted by states and approved by the EPA, requiring the EPA to develop and apply FIPs to those states that failed to submit an approvable reasonably attributable visibility impairment SIP.

Most of these FIPs contained planning requirements only. That is, most of the FIPs merely committed the EPA to assessing on a 3-year cycle whether reasonably attributable visibility impairment was occurring, and if so, to adopting an appropriate strategy of required emission controls.

52 FR 45132 (November 24, 1987).

C. Regional Haze

1. Requirements of the 1990 CAA Amendments and the EPA's Regional Haze Rule

In 1990, Congress added section 169B to the CAA to further address regional haze issues. Among other things, this section included provisions for the EPA to conduct visibility research on regional regulatory tools with the National Park Service and other federal agencies, and to provide periodic reports to Congress on visibility improvements due to implementation of other air pollution protection programs. CAA section 169B also generally allowed the Administrator to establish visibility transport commissions and specifically required the Administrator to establish a commission for the Grand Canyon area. The EPA promulgated a rule to address regional haze in 1999.

The 1999 RHR established a more comprehensive visibility protection program for Class I areas. The requirements for regional haze are found at 40 CFR 51.308 and 51.309.

64 FR 35714 (July 1, 1999).

The requirement to submit a regional haze SIP applies to all 50 states, the District of Columbia and the Virgin Islands.

Congress subsequently amended the deadlines for regional haze SIPs, and the EPA adopted regulations requiring states to submit the first implementation plans addressing regional haze visibility impairment no later than December 17, 2007.

These initial SIPs were to address emissions from certain large stationary sources and other requirements, which we discuss in greater detail later. Few states submitted a regional haze SIP by the December 17, 2007, deadline, and on January 15, 2009, the EPA found that 37 states, the District of Columbia and the Virgin Islands had failed to submit SIPs addressing the regional haze requirements.

These findings triggered a requirement for the EPA to promulgate FIPs within 2 years unless a state submitted a SIP and the EPA approved that SIP within the 2-year period.

Most states eventually submitted SIPs.

This requirement does not apply to other U.S. territories defined as “states” under the CAA because they do not have mandatory Class I Federal areas and are too distant from any such areas to affect them.

70 FR 39104 (July 6, 2005).

74 FR 2392 (January 15, 2009).

CAA section 110(c).

The 1999 RHR also required states to submit periodic comprehensive revisions of their regional haze SIPs. Under 40 CFR 51.308(f) of the 1999 RHR, states were required to submit the first such revision by no later than July 31, 2018, and every 10 years thereafter. These periodic comprehensive SIP revisions were required to address a number of elements, including current visibility conditions and actual progress made toward natural conditions during the previous implementation period; a reassessment of the effectiveness of the long-term strategy in achieving the RPGs over the prior implementation period; and affirmation of or revision to the RPGs. Further information on these periodic comprehensive SIP revisions can be found in Section III.B.3 of this document. In addition, the 1999 RHR's 40 CFR 51.308(g) required each state to submit progress reports, in the form of SIP revisions, every 5 years after the date of the state's initial SIP submission. In the progress reports, states were required to evaluate the progress made towards the RPGs for mandatory Class I areas located within the state, as well as those mandatory Class I areas located outside the state that may be affected by emissions from within the state. Further information on progress reports can be found in Section III.B.4 of this document.

The 1999 RHR sought to improve efficiency and transparency by requiring states to coordinate planning under the 1980 reasonably attributable visibility impairment provisions with planning under the provisions added by the 1999 RHR. The states were directed to submit reasonably attributable visibility impairment SIPs every 10 years rather than every 3 years, and to do so as part of the newly required regional haze SIPs. Many, but not all, states submitted initial regional haze SIPs that committed to this coordinated planning process. Coordination of reasonably attributable visibility impairment and regional haze planning is described in more detail later.

2. Roles of Agencies in Addressing Regional Haze

Successful implementation of the regional haze program requires long-term regional coordination among states, tribal governments and various federal agencies. As noted earlier, pollution affecting the air quality in Class I areas is emitted from many individual sources and can be transported over long distances, even hundreds of miles. Therefore, to effectively address the problem of visibility impairment in Class I areas, states need to develop strategies in coordination with one another, taking into account the effect of emissions from one jurisdiction on the air quality in another.

Because the pollutants that lead to regional haze can originate from sources located across broad geographic areas, and because these sources may be numerous and emit amounts of pollutants that, even though small, contribute to the collective whole, the EPA encourages states to address visibility impairment from a regional perspective. Five regional planning organizations (RPOs) were formed after the promulgation of the RHR in 1999 to address regional haze and related issues: The Central Regional Air Planning Association, the Mid-Atlantic/Northeast Visibility Union, the Midwest Regional Planning Organization, the Western Regional Air Partnership and the Visibility Improvement State and Tribal Association of the Southeast.

The RPOs first evaluated technical information to better understand how their states and tribes impact Class I areas across the country, and then supported the development (by states) of regional strategies to reduce emissions of pollutants that lead to regional haze.

See

“Visibility—Regional Planning Organizations,”

available at https://www.epa.gov/visibility/visibility-regional-planning-organizations.

3. Requirements for the Regional Haze SIPs

As mentioned earlier, states were required to submit SIPs addressing regional haze visibility impairment in 2007, which covered what we refer to as the first implementation period (2008-2018). A focus of the 2007 SIP obligation was to give specific attention to certain stationary sources that were in existence on August 7, 1977, but were not in operation before August 7, 1962, by requiring these sources, where appropriate, to install BART controls for the purpose of eliminating or reducing visibility impairment. These SIPs included a number of components and/

or analyses, which are described later along with information regarding whether or not this final rule impacts that particular SIP element.

BART Requirement.

Section 169A of the CAA directs states to evaluate the use of retrofit controls at certain larger, often uncontrolled, older stationary sources in order to address visibility impacts from these sources. Specifically, section 169A(b)(2)(A) of the CAA requires states to revise their SIPs to include such measures as may be necessary to make reasonable progress towards the natural visibility goal, including a requirement that certain categories of existing major stationary sources

procure, install and operate BART. Under the RHR, the EPA directed states to conduct BART determinations for any “BART-eligible” sources

that may be anticipated to cause or contribute to any visibility impairment in a Class I area. The EPA published the

Guidelines for BART Determinations Under the Regional Haze Rule

at appendix Y to 40 CFR part 51 (hereinafter referred to as the “BART Guidelines”) to assist states in determining which of their sources should be subject to the BART requirements and in determining appropriate emission limits for each applicable source.

The 1999 RHR also gave states the flexibility to adopt an emissions trading program or other alternative program in lieu of source-specific BART as long as the alternative provided greater reasonable progress towards improving visibility than BART and met certain other requirements set out in the 1999 RHR's 40 CFR 51.308(e)(2).

The set of “major stationary sources” potentially subject-to-BART is listed in CAA section 169A(g)(7).

BART-eligible sources are those sources that have the potential to emit 250 tons or more of a visibility-impairing air pollutant, were not in operation prior to August 7, 1962, but were in existence on August 7, 1977, and whose operations fall within one or more of 26 specifically listed source categories. 40 CFR 51.301.

70 FR 39104 (July 6, 2005).

States were required to undertake the BART determination process during the first implementation period. The BART requirement was a one-time requirement, but a BART-eligible source may need to be re-assessed for additional controls in future implementation periods under the CAA's reasonable progress provisions. Specifically, we anticipate that a number of BART-eligible sources that installed only moderately effective controls (or no controls at all) will need to be reassessed. Under the 1999 RHR's 40 CFR 51.308(e)(5), BART-eligible sources are subject to the requirements of 40 CFR 51.308(d), which addresses regional haze SIP requirements for the first implementation period, in the same manner as other sources going forward.

Under the 1999 RHR's 40 CFR 51.308(e)(5), BART-eligible sources were subject to the requirements of 40 CFR 51.308(d), which addresses regional haze SIP requirements for the first implementation period, in the same manner as other sources going forward.

Visibility Metric.

The RHR established the 24-hour deciview haze index as the principal metric or unit for expressing visibility on any particular day.

The deciview haze index is calculated from light extinction values and expresses uniform changes in the degree of haze in terms of common increments across the entire range of visibility conditions, from pristine to extremely hazy. Deciview values are calculated by using air quality measurements to estimate light extinction, most recently using the revised IMPROVE algorithm, and then transforming the value of light extinction using a logarithmic function.

The deciview is a more useful measure for comparing days and tracking progress in improving visibility than light extinction itself because each deciview change is an equal incremental change in visibility typically perceived by a human observer. Most people can detect a change in visibility of one deciview. The preamble to the 1999 RHR provided additional details about the deciview haze index.

See

70 FR 39104, 39118.

Pitchford, M.; Malm, W.; Schichtel, B.; Kumar, N.; Lowenthal, D.; Hand, J. Revised algorithm for estimating light extinction from IMPROVE particle speciation data; J. Air & Waste Manage. Assoc. 2007, 57, 1326-1336; doi: 3155/1047-3289.57.11.1326.

Baseline, Current and Natural Conditions and Tracking Changes in Visibility.

To track changes in visibility over time at each of the 156 Class I areas covered by the visibility program (40 CFR 81.401-437), and as part of the process for determining reasonable progress, states were required to calculate visibility conditions at each Class I area for a 5-year period just preceding each periodic comprehensive SIP revision.

To do this, the 1999 RHR required states to determine average visibility conditions (in deciviews) for the 20 percent least impaired days and the 20 percent most impaired days over the 5-year period at each of their Class I areas.

Under the 1999 RHR, states were also required to periodically review progress in reducing impairment every 5 years.

States were also required to develop an estimate of natural visibility conditions for the purpose of estimating progress toward the national goal. Natural visibility is determined by estimating the natural concentrations of pollutants that cause visibility impairment and then calculating total light extinction based on those estimates. The EPA has provided guidance to states regarding how to calculate baseline, natural and current visibility conditions at each Class I area.

After the EPA issued this guidance, a number of interested parties together developed a set of alternative estimates of natural conditions using a more refined approach (known as “NC-II”), which were used by most states in their first regional haze SIPs with EPA approval.

Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule, September 2003, EPA-454/B-03-005, available at

http://www3.epa.gov/ttn/caaa/t1/memoranda/rh_envcurhr_gd.pdf;

and Guidance for Tracking Progress Under the Regional Haze Rule, September 2003, EPA-454/B-03-004, available at

http://www3.epa.gov/ttn/oarpg/t1/memoranda/rh_tpurhr_gd.pdf.

Regional Haze Rule Natural Level Estimates Using the Revised IMPROVE Aerosol Reconstructed Light Extinction Algorithm, available at

http://vista.cira.colostate.edu/improve/Publications/GrayLit/032_NaturalCondIIpaper/Copeland_etal_NaturalConditionsII_Description.pdf;

Revised IMPROVE Algorithm for Estimating Light Extinction from Particle Speciation Data, available at

http://vista.cira.colostate.edu/improve/Publications/GrayLit/019_RevisedIMPROVEeq/RevisedIMPROVEAlgorithm3.doc;

and Regional Haze Data Analysis Workshop, June 8, 2005, Denver, CO, agenda and documents available at

http://www.wrapair.org/forums/aamrf/meetings/050608den/index.html.

Baseline visibility conditions reflect the degree of visibility impairment for the 20 percent least impaired days and 20 percent most impaired days for each calendar year from 2000 to 2004. Using monitoring data for 2000 through 2004, states are required to calculate the average degree of visibility impairment for each Class I area, based on the average of annual values of these two metrics over the 5-year period. The comparison of baseline visibility conditions to natural visibility conditions indicates the amount of improvement that would be necessary to attain natural visibility. Over time, the comparison of current visibility conditions

to the baseline visibility conditions will indicate the amount of progress that has been made.

Given the required timing of the first regional haze SIPs that were due by December 17, 2007, “baseline visibility conditions” were also the “current” visibility conditions. For future SIPs, “current conditions” will be updated to the 5-year period just preceding the SIP revision.

The 1999 RHR defined “visibility impairment” as a humanly perceptible change (

i.e.,

difference) in visibility from that which would have existed under natural conditions. The rule directed the tracking of visibility

impairment on the 20 percent “most impaired days” and 20 percent “least impaired days” in order to determine progress towards natural visibility conditions. 40 CFR 51.308(d)(2)(i-iv). In light of the 1999 RHR's definition of “impairment,” the term “impaired” in the phrases “most impaired days” and “least impaired days” could be taken to mean anthropogenic impairment only and to exclude reductions in visibility attributable to natural emission sources. However, the preamble to the 1999 RHR stated that the least and most impaired days were to be selected as the monitored days with the lowest and highest actual deciview levels caused by all sources, respectively. In 2003, the EPA issued guidance describing in detail the steps necessary for selecting and calculating light extinction on the “worst” and “best” visibility days, and this guidance also indicated that the monitored days with the lowest and highest actual deciview levels were to be selected as the least and most impaired days.

This approach worked well in many Class I areas but caused some concerns in other areas.

Guidance for Tracking Progress Under the Regional Haze Rule, September 2003,

http://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf

Specifically, the “worst” visibility days in some Class I areas can be impacted by irregularly occurring natural emissions (

e.g.,

wildland wildfires and dust storms). These natural contributions to haze vary in magnitude and timing. Anticipating this variability, in the 1999 RHR the EPA decided to use 5-year averages of visibility data to minimize the impacts of the interannual variability in natural events. However, additional data available through the IMPROVE monitoring network indicate that in many Class I areas 5-year averages are not sufficient for minimizing these erratic impacts. As a result, visibility improvements resulting from decreases in anthropogenic emissions can be hidden by this natural variability. Further, because of the logarithmic deciview scale, changes in PM concentrations and light extinction due to reductions in anthropogenic emissions have little effect on the deciview value on days with high PM concentrations and light extinction due to natural sources. The use of the days with the highest deciview index values, without consideration of the source of the visibility impacts, thus created difficulties when attempting to track visibility improvements resulting from controls on anthropogenic sources. States identified this difficulty prior to the start of this rulemaking and asked that the EPA explore options for focusing the visibility tracking metric on the effect of controlling anthropogenic emissions. To help states minimize the impacts of emissions from natural sources on visibility tracking via an approach that is also consistent with the CAA's goal to reduce visibility impairment resulting from man-made air pollution, the EPA proposed to more explicitly (and consistently) address this issue for future implementation periods.

Reasonable Progress Goals and Long-Term Strategy.

To ensure continuing progress towards achieving the natural visibility goal, the 1999 RHR required that each SIP submission in the series of periodic comprehensive regional haze SIPs establish two distinct RPGs (one for the most impaired and one for the least impaired days) for every Class I area.

See

40 CFR 51.308(d)(1). The 1999 RHR did not mandate specific milestones or rates of progress, but instead called for states to establish goals that provide for “reasonable progress” toward achieving natural visibility conditions. Specifically, states were required to provide for an improvement in visibility for the most impaired days over the period of the SIP, and ensure no degradation in visibility for the least impaired days over the same period.

To set their RPGs, states were required to consider the four statutory reasonable progress factors: (1) The costs of compliance; (2) the time necessary for compliance; (3) the energy and non-air quality environmental impacts of compliance; and (4) the remaining useful life of any potentially affected sources. States were required to demonstrate in their SIPs how these factors were considered when selecting the RPGs for the least impaired and most impaired days for each applicable Class I area. The RPGs are not enforceable.

64 FR 35754.

Consistent with the requirement in section 169A(b) of the CAA that states include in their regional haze SIPs a 10- to 15-year strategy for making reasonable progress, 40 CFR 51.308(d)(3) of the 1999 RHR required states to include a long-term strategy in their regional haze SIPs. Under the 1999 RHR, a state's long-term strategy is inextricably linked to the RPGs because the long-term strategy “must include enforceable emission limitations, compliance schedules, and other measures as necessary to achieve the reasonable progress goals established by states having mandatory Class I Federal areas.” 40 CFR 51.308(d)(3).

When setting their RPGs, states were also required to consider the rate of progress for the most impaired days that would be needed to reach natural visibility conditions by 2064 and the emission reduction measures that would be needed to achieve that rate of progress over the approximately 10-year period of the SIP. The purpose of this requirement was to allow for analytical comparisons between the rate of progress that would be achieved by the state's chosen set of control measures and the URP. If a state's RPG for the most impaired days achieved progress that was equal to the URP, the RPG would be “on the URP line”

or “on the glidepath.” If a state's RPG for the most impaired days was not on the glidepath, 40 CFR 51.308(d)(1)(ii) required the state to demonstrate that it would not be reasonable to require additional control measures and adopt an RPG that would be on the glidepath. The 1999 RHR did not establish an enforceable requirement that natural conditions be reached by 2064. The EPA approved a number of SIPs for the first implementation period that projected that continued progress at the rate expected to be achieved during the first period would not result in natural conditions until after 2064. However, the EPA also disapproved some SIPs during the first implementation period where states argued that no analysis of the four factors was necessary because visibility was projected to be “below the glidepath” at the end of the implementation period even without additional measures.

The URP for the most impaired days can be represented in a graphical manner by drawing the “URP line” on a chart with calendar year on the horizontal axis and deciviews for the 20 percent most impaired day on the vertical axis.

76 FR 64186 at 64195 (October 17, 2011) (proposed action on Arkansas's RPGs), 77 FR 14604 at 14612 (March 12, 2012) (final action on Arkansas's RPGs).

In setting their RPGs, each state with one or more Class I areas was also required to consult with potentially “contributing states,”

i.e.,

other nearby states with emission sources that may be affecting visibility impairment in the state's Class I areas. In such cases, the contributing state was required to demonstrate that it included in its long-term strategy all measures necessary to obtain its share of the emission reductions needed to make reasonable progress at the Class I area.

determining whether the upwind and downwind states' long-term strategies and RPGs provided for reasonable progress toward natural visibility conditions, the EPA was required to evaluate the demonstrations developed by the state. 40 CFR 51.308(d)(1).

This consultation obligation is a key element of the regional haze program. Congress, the states, the courts and the EPA have long recognized that regional haze is a regional problem that requires regional solutions.

Vermont

Thomas,

850 F.2d 99, 101 (2d Cir. 1988). Ultimately, early actions by states such as Vermont were influential in Congressional enactment of section 169B of the

CAA in 1990. Congress intended this provision of the CAA to “equalize the positions of the States with respect to interstate pollution,” (S. Rep. No. 95-127, at 41 (1977)) and our interpretation accomplishes this goal by ensuring that downwind states can seek recourse from us if upwind states are not doing enough to address visibility transport.

The 1999 RHR required states to consider all types of anthropogenic sources of visibility impairment when developing their long-term strategies, including major and minor stationary sources, mobile sources and area sources. States had to consider a number of factors when developing their long-term strategies, including: (1) Emission reductions due to ongoing air pollution control programs, including measures to address reasonably attributable visibility impairment; (2) measures to mitigate the impacts of construction activities; (3) emissions limitations and schedules for compliance; (4) source retirement and replacement schedules; (5) smoke management techniques for agricultural and forestry management purposes; (6) the enforceability of emissions limitations and control measures; and (7) the anticipated net effect on visibility due to projected changes in point, area and mobile source emissions over the period addressed by the long-term strategy. 40 CFR 51.308(d)(3)(v).

Coordinating Regional Haze and Reasonably Attributable Visibility Impairment.

The 1999 RHR fulfilled the EPA's responsibility to put in place a national regulatory program that addresses both reasonably attributable visibility impairment and regional haze. As part of the 1999 RHR, the EPA revised the schedule in 40 CFR 51.306(c) for the periodic review of reasonably attributable visibility impairment SIPs. The revised version of this subsection required that the reasonably attributable visibility impairment plan must continue to provide for a periodic review and SIP revision not less frequently than every 3 years until the date of submission of the state's first plan addressing regional haze visibility impairment. On or before this date, the state must have revised its plan to provide for periodic review and revision of a coordinated long-term strategy for addressing reasonably attributable visibility impairment and regional haze, and the state must have submitted the first such coordinated long-term strategy with its first regional haze SIP. Under the 1999 RHR, states were required to submit future coordinated long-term strategies, and periodic progress reports evaluating progress towards RPGs. The state's periodic review of its long-term strategy was required to report on both regional haze visibility impairment and reasonably attributable visibility impairment and was required to be submitted to the EPA in the form of a periodic comprehensive SIP revision. Under our proposed changes to the reasonably attributable visibility impairment provisions, this coordinated approach to a state's long-term strategies for regional haze and reasonably attributable visibility impairment would continue, but will apply in the infrequent case that a state receives a certification of reasonably attributable visibility impairment.

Monitoring Strategy and Other Implementation Plan Requirements.

40 CFR 51.308(d)(4) of the 1999 RHR included the requirement for a monitoring strategy for measuring, characterizing and reporting of regional haze visibility impairment that is representative of all mandatory Class I areas within the state. The strategy was required to be coordinated with the monitoring strategy required in the 1999 RHR version of 40 CFR 51.305 for reasonably attributable visibility impairment. Compliance with this requirement could be met through “participation” in the IMPROVE network.

A state's participation in the IMPROVE network includes state support for the use of CAA state and tribal assistance grants funds to partially support the operation of the IMPROVE network as well as the state's review and use of monitoring data from the network. The monitoring strategy was due with the first regional haze SIP, and under the 1999 RHR it must be reviewed every 5 years as part of the progress reports. The monitoring strategy must also provide for additional monitoring sites if the IMPROVE network is not sufficient to determine whether RPGs will be met. To date, neither the EPA nor any state has concluded that the IMPROVE network is not sufficient in this way. The evolution of the IMPROVE network will be guided by a Steering Committee that has FLM, EPA and state participation, within the evolving context of available resources. It is the EPA's objective that individual states will not be required to commit to providing monitoring sites beyond those planned to be operated by the IMPROVE program during the period covered by a SIP revision. Further, if the IMPROVE program must discontinue a monitoring site, this would not be a basis for an approved regional haze SIP to be found inadequate; but rather, the state, the federal agencies and the IMPROVE Steering Committee should work together to address the RHR requirements when the next SIP revision is developed. As described in Section IV.H of this document, we proposed that progress reports from individual states no longer be required to review and modify as necessary the state's monitoring strategy. The IMPROVE Steering Committee structure, the requirement to review the monitoring strategy as part of the periodic comprehensive SIP revision, and the requirement for a state to consider any recommendations from the EPA or a FLM for additional monitoring for purposes of reasonably attributable visibility impairment will be sufficient to achieve the objective of the current progress report requirement to review the monitoring strategy.

While compliance with 40 CFR 51.308(d)(4) for regional haze may be met through participation in the IMPROVE network, additional analysis or techniques beyond participation in IMPROVE may be required for compliance with 40 CFR 51.305 for reasonably attributable visibility impairment.

Consultation Between States and FLMs.

The 1999 RHR required that states consult with FLMs before adopting and submitting their SIPs. 40 CFR 51.308(i). There are two parts to this requirement. First, states must provide FLMs an opportunity for an in-person consultation meeting at least 60 days prior to holding any public hearing on the SIP. This consultation meeting was required to include the opportunity for the FLMs to discuss their assessment of impairment of visibility in any Class I area and to offer recommendations on the development of the RPGs and on the development and implementation of strategies to address visibility impairment. Further, a state was required to include in its SIP a description of how it addressed any comments provided by the FLMs. We proposed to require that states offer the opportunity for this already-required in-person consultation meeting early enough that information and recommendations provided by the FLMs can meaningfully inform the state's decisions on the long-term strategy. The second part of the consultation requirement is that a SIP must provide procedures for continuing consultation between the state and FLMs regarding the state's visibility protection program, including development and review of SIP revisions, progress reports, and the implementation of other programs having the potential to contribute to impairment of visibility in Class I areas.

We did not propose any change to this requirement for procedures for continuing consultation. This continuing consultation should provide opportunities for FLM input on the scope and methods for the state's technical analyses as they are being planned, while the in-person consultation meeting required by the first part of the consultation requirement will occur as a state is making decisions based on the conclusions of its technical analyses. FLMs often participate in multi-state workgroups on regional haze and related issues and attend multi-state meetings on these topics, which further facilitates collaboration with individual states during SIP development.

4. Requirements for the Regional Haze Progress Reports

The 1999 RHR included provisions for progress reports to be submitted at 5-year intervals, counting from the submission of the first required SIP revision by the particular state. The requirements for these reports were included for most states in 40 CFR 51.308(g) and (h). Three western states (New Mexico, Utah and Wyoming) exercised an option provided in the RHR to meet alternative requirements contained in 40 CFR 51.309 for their SIPs. For these three states, the requirements for the content of the 5-year progress reports are identical to those for the other states, but for these states the requirements for the reports were contained in 40 CFR 51.309(d)(10). This section specifies fixed due dates in 2013 and 2018 for these progress reports. The 1999 RHR then provided that these three states will revert to the progress report requirements in 40 CFR 51.308 after the report currently due in 2018. We did not propose this aspect of the RHR.

An explanation of the 5-year progress reports is provided in the preamble to the 1999 RHR.

This 5-year review was intended to provide an interim report on the implementation of, and if necessary mid-course corrections to, the regional haze SIP, which is generally prepared in 10-year increments. The progress report provides an opportunity for public input on the state's (and the EPA's) assessment of whether the approved regional haze SIP is being implemented appropriately and whether reasonable visibility progress is being achieved consistent with the projected visibility improvement in the SIP.

64 FR 35747 (July 1, 1999).

Required elements of the progress report under the 1999 RHR included: The status of implementation of all measures included in the regional haze SIP; a summary of the emissions reductions achieved throughout the state; an assessment of current visibility conditions and the change in visibility impairment over the past 5 years; an analysis tracking the change over the past 5 years in emissions of pollutants contributing to visibility impairment from all sources and activities within the state; an assessment of any significant changes in anthropogenic emissions within or outside the state that have occurred over the past 5 years that have limited or impeded progress in reducing pollutant emissions and improving visibility; an assessment of whether the current SIP elements and strategies are sufficient to enable the state (or other states with mandatory Class I areas affected by emissions from the state) to meet all established RPGs; a review of the state's visibility monitoring strategy and any modifications to the strategy as necessary; and a determination of the adequacy of the existing SIP (including taking one of four possible actions).

We proposed to include a number of clarifications and changes to the requirements for the content of progress reports.

40 CFR 51.308(g).

See

also General Principles for the 5-Year Regional Haze Progress Reports for the Initial Regional Haze State Implementation Plans (Intended to Assist States and EPA Regional Offices in Development and Review of the Progress Reports), April 2013, EPA-454/B-03-005, available at

https://www.epa.gov/sites/production/files/2016-03/documents/haze_5year_4-10-13.pdf,

(hereinafter referred to as “our 2013 Progress Report Guidance”).

Under the 1999 RHR's 40 CFR 51.308(g) and 40 CFR 51.309(d)(10), progress reports must take the form of SIP revisions, so states must follow formal administrative procedures (including public review and opportunity for a public hearing) before formally submitting the 5-year progress report to the EPA.

See

40 CFR 51.102, 40 CFR 51.103, and Appendix V to Part 51—Criteria for Determining the Completeness of Plan Submissions. We proposed to remove the requirement that progress reports be submitted as SIP revisions.

In addition, because progress reports were SIP revisions under the 1999 RHR, states were required to provide FLMs with an opportunity for in-person consultation at least 60 days prior to any public hearing on progress report.

See

1999 RHR version of 40 CFR 51.308(i)(2) and (3). Procedures must also be provided for continuing consultation between the state and FLM regarding development and review of progress reports.

See

40 CFR 51.308(i)(4).

Under the 1999 RHR, the first progress reports were due 5 years from the initial SIP submittal (with the next progress reports for New Mexico, Utah, and Wyoming due in 2018). Most of these deadlines have already passed although some are due in 2016 and in 2017.

A number of first progress reports have been submitted by states. Several of these progress reports have been approved, action on several others has been proposed, and EPA is still reviewing the other submitted reports. There are also states for which progress reports are overdue, and a few states for which progress reports are not yet due and have not been submitted.

5. Tribes and Regional Haze

Tribes have a distinct interest in regional haze due to the effects of visibility impairment on tribal lands as well as on other lands of high value to tribal members, such as landmarks considered sacred. Tribes, therefore, have a strong interest in emission control measures that states and the EPA incorporate into SIPs and FIPs with regard to regional haze, and also have an interest in the state response to any certification of reasonably attributable visibility impairment made by an FLM.

The agency has a tribal consultation policy that covers any plan that the EPA would promulgate that may affect tribal interests. This consultation policy applies to situations where a potentially affected source is located on tribal land, as well as situations where a SIP or FIP concerns a source that is located on state land and may affect tribal land or other lands that involve tribal interests. In addition, the EPA has and will continue to consider any tribal comments on any proposed action on a SIP or FIP.

Like the EPA, the Department of the Interior and the U.S. Forest Service in the U.S. Department of Agriculture have strong tribal consultation policies.

See: http://www.epa.gov/tribal/consultation/index.htm; http://www.fs.fed.us/spf/tribalrelations/authorities.shtml,

and

https://www.doi.gov/tribes/Tribal-Consultation-Policy.

In the first implementation period for regional haze SIPs, the partnerships within the RPOs included strong relationships between the states and the tribes, and the EPA encourages states to continue to invest in those relationships (including consulting with tribes), particularly with respect to tribes located near Class I areas. States should continue working directly with tribes on their SIPs and their response to any certification of reasonably attributable visibility impairment made by an FLM. It is preferable for states to address tribal concerns during their planning process rather than the EPA addressing such concerns in its subsequent rulemaking process. During the development of this rulemaking, the EPA was asked by the

National Tribal Air Association to adopt a requirement that states formally consult with tribes during the development of their regional haze SIPs. The CAA does not explicitly authorize the EPA to impose such a requirement on the states. While we recognize the value of dialogue between state and tribal representatives, we did not propose to require it.

D. Air Permitting

One part of the visibility protection program, 40 CFR 51.307, New Source Review (NSR), was established in 1980 with the rationale that while most new sources that may impair visibility were already subject to review under the Prevention of Significant Deterioration provisions (part C of Title I of the CAA), additional regulations would “ensure that certain sources exempt from the PSD regulations because of geographic criteria will be adequately reviewed for their potential impact on visibility in the mandatory Class I Federal area.”

The EPA explained at proposal that this was necessary because the PSD regulations did not call for the review of major emitting facilities (or major modifications) located in nonattainment areas,

and that it was appropriate to “clarify certain procedural relationships between the FLM and the state in the review of new source impacts on visibility in Federal class I areas.”

The EPA envisioned that state and FLM consultation would commence with the state notifying the FLM of a potential new source, and that consultation would continue throughout the permitting process. We proposed to revise 40 CFR 51.307 only as needed to maintain consistency with revisions to other sections of 40 CFR part 50 subpart P.

45 FR 80084 (December 2, 1980).

In 1978, PSD rules were put in place that required permitting agencies to interact with FLMs and for air quality related values (AQRVs) to be taken into consideration in the PSD permitting process. 43 FR 26380 (June 19, 1978). Those PSD rules did not cover sources in nonattainment areas, and while there were EPA rules for nonattainment NSR in existence, they did not require consideration of Class I areas. In 1979, 40 CFR part 51, appendix S established rules for nonattainment permitting, but they did not (and still do not) require consideration of visibility or FLM notification. (The same is also true of a more recent addition, 40 CFR 51.165. Where applicable to nonattainment areas, this rule does not require Class I reviews. While 40 CFR 51.165(b) requires that sources located in attainment areas cannot cause or contribute to a NAAQS violation anywhere, this does not cover AQRVs in Class I areas.) As a result, in 1980, the EPA added requirements to 40 CFR 51.307 for notification of FLMs of pending permits for new sources in nonattainment areas.

45 FR 34765 (May 22, 1980).

IV. Final Rule Revisions

The EPA is finalizing revisions to the agency's visibility regulations that are intended to build upon the progress achieved by the visibility program over the last decade while streamlining certain administrative requirements that are unnecessarily burdensome. The EPA gained a substantial amount of knowledge during the first regional haze implementation period and learned what aspects of the program work well and what aspects could benefit from modification. The EPA received information and perspectives from air agencies and FLMs during this period that were invaluable in developing the proposal. We also received comments from a wide variety of other stakeholders during the public comment process, including groups of states, FLMs, industry and industry representatives, nongovernmental organizations, and others. We considered all timely comments submitted on the proposal and address many of the most significant comments in this section. We are also providing a separate response-to-comments (RTC) document in the docket for this rulemaking. Between this preamble and the RTC document, we have responded to all significant comments received on this rulemaking.

A. Ongoing Litigation in Texas

EPA

A number of state and industry stakeholders submitted comments regarding the ongoing litigation in the Fifth Circuit Court of Appeals over the EPA's January 2016 final action that partially approved and partially disapproved the Oklahoma and Texas regional haze SIPs for the first implementation period and promulgated partial FIPs for each state.

These commenters asserted that the Fifth Circuit's decision granting a stay

of the Texas FIP's reasonable progress emission limits undermined our proposed revisions to the visibility regulations. Some commenters also suggested that we must suspend our rulemaking revising the visibility regulations until after the Fifth Circuit has issued a decision on the merits.

81 FR 295 (January 5, 2016).

Texas

EPA,

2016 U.S. App. LEXIS 13058 (5th Cir. July 15, 2016).

We disagree that the Fifth Circuit's recent stay decision in

Texas

EPA

dictates the lawfulness or timeliness of this rulemaking. First, as the commenters have noted, the Fifth Circuit decision was not a final decision on the merits of our action on the Oklahoma and Texas regional haze SIPs; instead, it was a preliminary decision issued by a panel of Fifth Circuit judges reviewing motions to stay the EPA's FIP, otherwise referred to as a “motions panel.” That panel expressly noted that its “determination of Petitioners' likelihood of success on the merits is for the purposes of the stay only and does not bind the merits panel.”

Second, and more importantly, the Fifth Circuit's evaluation of the EPA's FIP was based on the existing visibility regulations at 40 CFR 51.308(d). In this rulemaking, we are promulgating new regulations at 40 CFR 51.308(f) that will govern the second and future implementation periods. Under CAA section 307(b), the D.C. Circuit Court of Appeals is the exclusive venue for judicial review of these regulations. Consequently, the preliminary views of another circuit on the lawfulness of a FIP issued in the first implementation period under our existing regulations at 40 CFR 51.308(d) are not germane to this rulemaking. Third, portions of the stay decision indicate a fundamental misunderstanding of aspects of the visibility program and the EPA's action on the Oklahoma and Texas regional haze SIPs. For example, the decision on several occasions conflated the BART and reasonable progress requirements of the RHR, even though the FIP solely concerned the latter.

Indeed, we explicitly delayed final action in promulgating a FIP to address the BART requirements for EGUs in Texas in light of the D.C. Circuit's decision to remand several of the Cross-State Air Pollution Rule's (CSAPR) emissions budgets.

Id.

at *42 n.29.

See, e.g., id.

at *8 (SIPs must “list the best available retrofit technology (`BART') that emission sources in the state will have to adopt to achieve the visibility goals”);

id.

at *9 (“BART is the only portion of the implementation plan that is enforced against emission sources in a state.”);

id.

at *42 (asserting that “the BART requirements” are “the portion of the Final Rule imposing injury on Petitioners”).

81 FR 301-02.

While the decision in

Texas

EPA

does not dictate the outcome of this rulemaking, the decision has created some confusion regarding certain aspects of the visibility program, including (1) whether states can or must consider the four reasonable progress factors on a source-specific basis; (2) the scope of the consultation requirements; and (3) whether a state's long-term strategy can contain measures that cannot be fully implemented by the end of an implementation period. Consequently, we believe that it is appropriate to address each of these issues at this time to explain how it was treated under the existing regulations during the first implementation period and whether it will be treated any

differently (and if so how) under the new regulations governing future implementation periods.

1. Source-Specific Analysis

Texas

EPA,

the Fifth Circuit explained that neither the RHR nor the CAA requires a state to conduct a source-specific four-factor analysis.

Several commenters cited this aspect of the Fifth Circuit's decision to argue that the EPA's proposal could not require states to conduct source-specific four-factor analyses and that, while states could conduct such analyses at their discretion, a state's decision not to do so could not form the basis of the EPA's disapproval of a SIP. Other commenters argued that proposed 40 CFR 51.308(f)(3)(ii) would unlawfully force states to conduct source-specific four-factor analyses if a state's RPGs provide for a slower rate of improvement in visibility than the URP. Several commenters asked us to clarify our position on these issues.

Id.

at *45-51.

Neither the 1999 RHR nor the revised regulations in this rulemaking require states to conduct four-factor analyses on a source-specific basis. CAA section 169A(b)(2) requires states to include in their SIPs “emission limits, schedules of compliance and other measures as may be necessary to make reasonable progress.” While these emission limits must apply to individual sources or units, section 169A(g)(1) does not explicitly require states to consider the four factors on a source-specific basis when determining what amount of emission reductions (and corresponding visibility improvement) constitutes “reasonable progress.” Unlike section 169A(g)(2), which requires states to consider “any existing control technology in use at

the source

” and “the remaining useful life of

the source

” when determining BART, section 169A(g)(1) refers to the four factors more generally. For example, with respect to remaining useful life, section 169A(g)(1) refers not to “the source,” but rather “any existing source subject to such requirements.” Thus, the EPA has consistently interpreted the CAA to provide states with the flexibility to conduct four-factor analyses for specific sources, groups of sources or even entire source categories, depending on state policy preferences and the specific circumstances of each state. This is the case under the 1999 RHR and continues to be the case under these final revisions. Contrary to the arguments in some comments, 40 CFR 51.308(f)(3)(ii) explicitly refers to “sources

or groups of sources.

” Similarly, 40 CFR 51.308(f)(2)(i) also refers to “major or minor stationary sources

or group of sources,

mobile sources, and area sources.”

We also note that the stay decision in

Texas

EPA

mistakenly indicated that the EPA disapproved the Texas SIP for failing to evaluate the four factors on a source-specific basis. As we explained in the January 2016 final rule, we disapproved Texas's four-factor analysis because the set of sources and controls that Texas analyzed was both over-inclusive and under-inclusive, not because the state failed to conduct a source-specific analysis.

Texas's analysis was over-inclusive because it included controls on sources that served only to increase total costs with little corresponding visibility benefit, and under-inclusive because it did not include scrubber upgrades that would achieve highly cost-effective emission reductions that would lead to significant visibility improvements. While these final revisions to the RHR continue to provide states with considerable flexibility in evaluating the four reasonable-progress factors, we expect states to exercise reasoned judgment when choosing which sources, groups of sources or source categories to analyze. Consistent with CAA section 169A(g)(1) and our action on the Texas SIP, a state's reasonable progress analysis must consider a meaningful set of sources and controls that impact visibility. If a state's analysis fails to do so, for example, by arbitrarily including costly controls at sources that do not meaningfully impact visibility or failing to include cost-effective controls at sources with significant visibility impacts, then the EPA has the authority to disapprove the state's unreasoned analysis and promulgate a FIP.

81 FR 313-14.

2. Interstate Consultation

In the

Texas

EPA

stay decision, the Fifth Circuit explained that neither the RHR nor the CAA explicitly require upwind states to provide downwind states with source-specific emission control analyses.

Consistent with Congress's focus on interstate cooperation under section 169B, the 1999 RHR required states to consult with one another when developing their RPGs and long-term strategies, develop “coordinated emission management strategies” and document any disagreements regarding their goals and strategies.

We agree with the Fifth Circuit that the 1999 RHR did not require upwind states to provide downwind states with a specific type of four-factor analysis during the consultation process; the four-factor analysis that the upwind state did could be based on a source-specific or aggregate approach, for example. The consultation provisions were intended to foster and facilitate regional solutions to what is, by definition, a regional problem, not to mandate specific outcomes. The final revisions largely preserve the existing consultation provisions and similarly do not require upwind states to provide downwind states with any specific type of analysis, or vice versa. Nevertheless, to develop coordinated emission management strategies, each state must make decisions with respect to its own long-term strategy with knowledge of what other states are including in their strategies and why. In other words, states must exchange their four-factor analyses and the associated technical information that was developed in the course of devising their long-term strategies. This information includes modeling, monitoring and emissions data and cost and feasibility studies. To the extent that one state does not provide another other state with these analyses and information, or to the extent that the analyses or information are materially deficient, the latter state should document this fact so that the EPA can assess whether the former state has failed to meaningfully comply with the consultation requirements.

Id.

at *51-53.

40 CFR 51.308(d)(1)(iv); (d)(3)(i).

3. Timing of Control Requirements

Lastly, in

Texas

EPA,

the Fifth Circuit's stay decision suggested that it was likely that the EPA had exceeded its statutory authority by imposing emission controls that go into effect after the end of the implementation period.

This preliminary assessment is incorrect for several reasons.

Texas,

2016 U.S. App. LEXIS 13058 at *53-57.

First, we note that the decision did not cite to a provision of the CAA to support the proposition that the EPA exceeded its statutory authority. Indeed, the CAA includes no such constraint. Two provisions are of particular relevance. Section 169A(b)(2)(B) requires SIPs to include “a long-term (ten to fifteen years) strategy for making reasonable progress toward meeting the national goal.” The phrase “ten to fifteen years” is ambiguous. It could mean that the long-term strategy must be updated every 10 to 15 years or that the strategy must be fully implemented within 10 to 15 years. Even under the latter interpretation, courts have held that an agency does not lose authority to regulate when a mandatory deadline

has passed; rather, the appropriate remedy is an order compelling agency action.

We therefore do not interpret this provision as restricting the authority of states or the EPA to include control measures in a SIP or FIP that cannot be fully implemented by the end of a regulatory implementation period or as relaxing their obligation to include such controls if they are otherwise necessary to make reasonable progress. To do so would create an inappropriate incentive for states to delay their SIP submittals in an effort to “run out the clock” on the EPA's authority to issue a corrective FIP.

Oklahoma

EPA,

723 F.3d 1201, 1223-24 (10th Cir. 2013) (citing

Brock

Pierce Cty.,

476 U.S. 253, 260 (1986).

Also, section 169A(g)(1) requires states to consider “the time necessary for compliance” when determining what control measures are necessary to make reasonable progress. This phrase is also ambiguous. One possible interpretation of the phrase is that states need only consider control measures that can be implemented within a certain period of time. This interpretation is unreasonable, however, because it would allow states to forever forgo cost-effective but time-intensive emission reduction measures that could otherwise improve visibility, which would thwart Congress's national goal. A more reasonable interpretation of the phrase is that states must consider the feasibility of the “schedules of compliance” referred to in section 169A(b)(2) when determining when the emission reductions necessary to make reasonable progress must be implemented. The structure of section 169A also lends support to this interpretation. When determining reasonable progress, states must consider three of the same factors that they consider when determining BART. The only unique reasonable progress factor relates to timing: “the time necessary for compliance.” Congress had no reason to include a timing factor for BART, however, because section 169A(b)(2)(A) already includes a requirement that BART must be installed and operated “as expeditiously as practicable,” which section 169A(g)(4) defines as no later than 5 years from the date of plan approval. With no similar requirement in section 169(b)(2), it is reasonable to interpret that Congress intended “the time necessary for compliance” factor to serve an analogous function to the “expeditiously as practicable” language, albeit with more discretion left to the states.

Second, we note that the Fifth Circuit appeared to misunderstand a provision in the 1999 RHR that it used to support its decision. Specifically, the stay decision stated:

The Regional Haze Rule requires states to “consider . . . the emission reduction measures needed to achieve [the reasonable progress goal]

for the period covered by the implementation plan,

” and to impose “enforceable emissions limitations, compliance schedules, and other measures, as necessary to achieve the reasonable progress goals.” 40 CFR 51.308(d)(1)(i)(B), (d)(3) (emphasis added). The Regional Haze Rule provides that each implementation plan will cover a ten-year period; before the close of each ten-year period, the state must submit a comprehensive revision to cover the next ten-year period. 40 CFR 51.308(b), (f) (first implementation plan due December 2007; first “comprehensive periodic revision” due July 31, 2018, and every ten years thereafter). The emissions controls included in a state implementation plan, therefore, must be those designed to achieve the reasonable progress goal for the period covered by the plan. 40 CFR 51.308(d)(1)(i)(B).

Texas,

2016 U.S. APP. LEXIS 13058 at *53-54.

However, 40 CFR 51.308(d)(1)(i)(B) does not actually say that states must consider the emission reductions measures needed to achieve “the reasonable progress goal” for the period covered by the implementation plan. Instead, it requires states to “consider

the uniform rate of improvement in visibility

and the emission reduction measures needed to achieve

for the period covered by the implementation plan.”

In essence, the provision requires a state to make a comparison between its chosen control set and the specific set of control measures that would be needed to achieve the URP by the end of the implementation period. The provision does not dictate the date by which all of the measures in a state's chosen control set must be implemented.

40 CFR 51.308(d)(1)(i)(B) (emphases added).

Third, the stay decision did not discuss the EPA's 2007 reasonable progress guidance, which specifically recognized that the time needed for full implementation of a control measure might extend beyond the end of the implementation period. In such situations, the EPA stated that it may be appropriate for states to use the time necessary for compliance factor “to adjust the [RPG] to reflect the degree of improvement in visibility achievable within the period of the first SIP,”

which would prevent the state from falling short of its goal. The 2007 guidance did not state that the CAA or the 1999 RHR prohibited states from requiring the control measure.

Guidance for Setting Reasonable Progress Goals Under the Regional Haze Program, revised, at 5-2 (June 1, 2007).

In the proposal for this rulemaking, which was promulgated before the Fifth Circuit's stay decision, we did not address this issue. At that time, we thought that it was clear that neither states nor the EPA lose the authority to require emissions limits or other measures that are necessary to make reasonable progress if those limits or measures cannot be fully implemented by the end of the implementation period and incorporated into the RPGs. For the reasons provided previously, we continue to believe that this is the case.

Therefore, we are modifying 40 CFR 51.308(f)(2)(i) to explicitly provide that, when considering the time necessary for compliance, a state may not reject a control measure because it cannot be installed and become operational until after the end of the implementation period. As discussed previously, the state should instead consider that fact in determining the appropriate compliance deadline for the measure. Of course, any emission reductions that will not occur until after the end of the implementation period should not be reflected in the RPGs.

In addition, to avoid any future confusion with respect to this issue, we are making a small modification to 40 CFR 51.308(f)(3)(i) in these final revisions. This final provision now reads:

A State in which a mandatory Class I Federal area is located must establish reasonable progress goals (expressed in deciviews) that reflect the visibility conditions that are projected to be achieved by the end of the applicable implementation period as a result of

those

enforceable emissions limitations, compliance schedules, and other measures required under paragraph (f)(2)

that can be fully implemented by the end of the applicable implementation period,

as well as the implementation of other requirements of the CAA.

This modification makes it clear that a state's long-term strategy can include emission limits and measures beyond those reflected in the state's RPGs. The RPGs are unenforceable tracking metrics. They are not meant to dictate or limit the content of a state's long-term strategy for making reasonable progress towards Congress's national goal. This change is also consistent with our actions promulgating FIPs near the end of the first implementation period, which by necessity included reasonable progress emission limits with compliance deadlines after 2018.

81 FR 296 (January 5, 2016) (Texas); 81 FR 68319 (October 4, 2016) (Arkansas).

B. Cooperative Federalism

Some commenters invoked principles of cooperative federalism to argue that the proposed revisions were too prescriptive and thus undermined the discretion afforded to states by the CAA. As support for this argument, the commenters pointed almost exclusively to the Fifth Circuit's stay decision in

Texas

EPA,

discussed previously, in which a motions panel of the Fifth Circuit described EPA's role in reviewing SIPs as “ministerial.”

Commenters also suggest the proposed revisions are inconsistent with the principles announced in

American Corn Growers Association

EPA,

291 F.3d 1 (D.C. Cir. 2002) (“Corn Growers”).

Texas,

206 U.S. App. LEXIS 13058 at *5.

As a preliminary matter, the commenters' reliance on

Texas

EPA

is misplaced. The view expressed in the stay decision, that the EPA has only a “ministerial function” in reviewing SIPs, is at odds with the great majority of courts that have considered this issue in the context of the regional haze program. Under the principles of cooperative federalism, the CAA vests state air agencies with substantial discretion as to how to achieve Congress's air-quality goals and standards, but states exercise this authority with federal oversight. As the Tenth Circuit explained in

Oklahoma

EPA,

“the EPA reviews all SIPs to ensure that they comply with the [CAA],” and “[t]he EPA may not approve any plan that `would interfere with any applicable requirement' of [the Act].”

Relying on

Oklahoma,

the Eighth Circuit in

North Dakota

EPA

held that the “EPA is left with more than the ministerial task of routinely approving SIP submissions,”

and that the “EPA's review of a SIP extends not only to whether the state considered the necessary factors in its determination, but also to whether the determination is one that is reasonably moored to the CAA's provisions.”

Similarly, in

Arizona

EPA,

the Ninth Circuit held that the “EPA is not limited to the `ministerial' role of verifying whether a determination was made; it must `review the substantive content of the . . . determination,' ”

and that the “EPA has a

substantive

role in deciding whether state SIPs are compliant with the Act and its implementing regulations.”

In accord with these principles, the Third Circuit recently remanded the EPA's approval of a state's regional haze SIP where the EPA deferred too readily to state conclusions without providing a sufficient explanation for overlooking problems in the SIP.

Thus, the view expressed by the Fifth Circuit motions panel in the stay decision is an outlier.

Oklahoma

EPA,

723 F.3d 1201, 1204 (10th Cir. 2013).

North Dakota

EPA,

730 F.3d 750, 761 (8th Cir. 2013).

Id.

at 766.

Ariz. el rel. Darwin

EPA,

815 F.3d 519, 531 (9th Cir. 2016).

Id.

at 532 (emphasis in original).

Nat'l Parks Conservation Ass'n

EPA,

803 F.3d 151, 167 (3d Cir. 2015).

More importantly, however, the situation in

Texas

EPA

is inapposite to the situation here. In

Texas,

we partially disapproved an individual state's implementation plan and promulgated a FIP to fill the gap. In this rulemaking, we are not expressing views on any state's implementation plan, so it is simply premature to suggest that we are affording insufficient deference to state choices. Rather, we are promulgating revisions to the existing visibility regulations that will guide future SIP development. In 1977, Congress expressly required the EPA to promulgate regulations “to assure (A) reasonable progress toward meeting the national goal . . . and (B) compliance with the requirements of [section 169A].”

Congress also required the EPA's regulations to “provide guidelines to the States”

regarding “methods for identifying, characterizing, determining, quantifying, and measuring visibility impairment;”

“modeling techniques for determining the extent to which manmade air pollution may reasonably be anticipated to cause or contribute to such impairment;”

and “methods for preventing and remedying such manmade air pollution and resulting visibility impairment.”

In 1990, Congress reiterated this statutory obligation, tasking the EPA again with carrying out its “regulatory responsibilities under [section 169A], including criteria for measuring `reasonable progress' toward the national goal.”

CAA section 169A(b).

CAA section 169A(b)(1).

CAA section 169A(a)(3)(A).

CAA section 169A(a)(3)(B).

CAA section 169A(a)(3)(C).

CAA section 169B(e)(1).

These final revisions to the 1999 RHR and 1980 reasonably attributable visibility impairment regulations are fully consistent with this extensive grant of rulemaking authority. The revisions will ensure that the steady environmental progress achieved during the first implementation period continues, while streamlining several administrative aspects of the program to reduce burdens on states. The revisions require states to consider certain factors and provide certain information as they develop their regional haze SIPs, but they do not mandate specific outcomes. Where applicable, the revisions also provide states with significant flexibility to take state-specific facts and circumstances into account when developing their long-term strategies.

Thus, contrary to the commenters' assertions, the final revisions are fully consistent with the CAA's cooperative-federalism framework and the decision in

Corn Growers,

which addressed EPA's authority to require states to consider the visibility benefits of BART controls in a specific fashion, a set of facts not present in this rulemaking, is not on point.

See, e.g.,

81 FR at 26954/1 (explaining that states have the flexibility to justify and use values for natural visibility conditions that include anthropogenic international emissions).

C. Clarifications To Reflect the EPA's Long-Standing Interpretation of the Relationship Between Long-Term Strategies and Reasonable Progress Goals

1. Summary of Proposal

Under the 1999 RHR, states were required to revise their regional haze SIPs every 10 years by evaluating and reassessing all of the elements required under 40 CFR 51.308(d).

Over the course of the first implementation period, however, we realized that some of the requirements in 40 CFR 51.308(d) were creating confusion regarding the relationship between RPGs and the long-term strategy and the respective obligations of upwind and downwind states. We discussed this issue at length in our December 14, 2014, proposed action on the Texas and Oklahoma regional haze SIPs,

and incorporated that discussion by reference in the proposal for this rulemaking.

40 CFR 51.308(f).

79 FR 74823-30 (December 14, 2014).

81 FR 26949, 26952.

For example, under 40 CFR 51.308(d), states were required to (1) develop RPGs, (2) calculate baseline and natural visibility conditions, (3) establish long-term strategies and (4) adopt monitoring strategies and other measures to track future progress and ensure compliance. The sequencing of these requirements in the rule text was problematic because it did not accord with the way the planning process works in practice. For example, states must calculate baseline and natural visibility conditions before they can compare their RPGs to the URP. Similarly, states must evaluate the control measures that are necessary to

make reasonable progress using the four factors and develop their long-term strategies before they can predict future emission reductions and conduct the regional-scale modeling used to establish RPGs.

Similarly, problematic was the confusing way in which 40 CFR 51.308(d) addressed the obligations of upwind and downwind states. Under 40 CFR 51.308(d)(1)(i)(A), downwind states were explicitly required to consider the four factors when developing their RPGs. Upwind states, on the other hand, were implicitly required to consider the four factors only when developing their long-term strategies. Section 40 CFR 51.308(d)(3)(iii) required states to “document the technical basis, including modeling, monitoring and emissions information, on which the State is relying

to determine its apportionment of emission reduction obligations necessary for achieving reasonable progress in each mandatory Class I Federal area it affects.

” As we explained in our December 14, 2014, proposed action on the Texas and Oklahoma regional haze SIPs, the CAA requires states to determine reasonable progress by considering the four factors, so the determination of the proper apportionment of emission reductions necessarily required a state to evaluate the four factors in reaching its decision. This structure made little sense because both upwind and downwind states need to conduct their four-factor analyses, determine the proper apportionment of emission reduction obligations, and develop their long-term strategies before the downwind state will have sufficient information to establish RPGs.

Recognizing that the sequence and structure of the existing regulations was confusing, we proposed to amend 40 CFR 51.308(f), which governs periodic SIP revisions for future implementation periods, to codify our long-standing interpretation of the way in which the existing regulations were intended to operate. Specifically, we proposed to eliminate the cross-reference in 40 CFR 51.308(f) to 40 CFR 51.308(d) and to adopt new regulatory language that tracked the actual planning sequence, while clarifying the obligations of upwind and downwind states.

Under the proposal, states would (1) calculate baseline, current and natural visibility conditions, progress to date and the URP; (2) develop a long-term strategy for addressing regional haze by evaluating the four factors to determine what emission limits and other measures are necessary to make reasonable progress; (3) conduct regional-scale modeling of projected future emissions under the long-term strategies to establish RPGs and then compare those goals to the URP line;

and (4) adopt a monitoring strategy and other measures to track future progress and ensure compliance.

81 FR 26952.

This step applies only to downwind states that have mandatory Class I Federal areas.

2. Comments and Responses

In response to our proposed structural revisions to 40 CFR 51.308(f), we received a number of significant comments. Some commenters contended that the proposed revisions were contrary to the structure and plain language of the CAA. They explained the position that states must first make a “determination” as to what constitutes “reasonable progress” by analyzing the four statutory factors on a source-category basis. Then, only after “reasonable progress” is quantified as a benchmark or goal do states have to consider what emission limits, schedules of compliance and other measures at individual sources are actually necessary to make reasonable progress. The commenters further explained that this reading of the statute was supported by the current regulations, the preamble to the 1999 RHR and the EPA's prior guidance. Based on their reading, these commenters concluded that proposed 40 CFR 51.308(f)(2), which would govern long-term strategies, and proposed 40 CFR 51.308(f)(3), which would govern RPGs, were contrary to the CAA because states must first determine reasonable progress independently from the development of the long-term strategy, not the other way around.

We disagree. Our proposed structural revisions to 40 CFR 51.308(f) are consistent with the CAA. Section 169A(b)(2) requires states to submit SIP revisions that contain “emission limits, schedules of compliance and other measures as necessary to make reasonable progress toward meeting the national goal” and “a long-term (ten to fifteen years) strategy for making reasonable progress.” Section 169A(g)(1) states that, in determining reasonable progress, states must consider four factors: “the costs of compliance, the time necessary for compliance, and the energy and nonair quality environmental impacts of compliance, and the remaining useful life of any existing source subject to such requirements.” Under 40 CFR 51.308(f)(2), both as proposed and as we are finalizing it, states must similarly submit a “long-term strategy” that includes “enforceable emissions limitations, compliance schedules, and other measures that are necessary to make reasonable progress,” and determine those limits, schedules, and measures by considering the four statutory factors.

We disagree that the CAA requires EPA's regulations to allow states to calculate the visibility improvement that represents “reasonable progress” prior to or independently from the analysis of control measures. The commenters do not explain how states could consider costs, time schedules, energy and environmental impacts or the remaining useful lives of sources other than by assessing the potential impacts of control measures on those sources. Indeed, use of the terms “compliance” and “subject to such requirements” in section 169A(g)(1) strongly indicates that Congress intended the relevant determination to be the requirements with which sources would have to comply in order to satisfy the CAA's reasonable progress mandate. Moreover, the reasonable progress factors share obvious similarities with the BART factors, which are indisputably used to determine appropriate control measures for sources.

Compare

CAA section 169A(g)(1)

with

CAA section 169A(g)(2).

Finally, we note that RPGs are not a concept that is included in the CAA itself. Rather, they are a regulatory construct that we developed to satisfy a separate statutory mandate in section 169B(e)(1), which required our regulations to include “criteria for measuring `reasonable progress' toward the national goal.”

Under 40 CFR 51.308(f)(3)(ii), RPGs continue to serve this important analytical function. They measure the progress that is projected to be achieved by the control measures states have determined are necessary to make reasonable progress based on a four-factor analysis. Consistent with the 1999 RHR, the RPGs are unenforceable,

but they create a benchmark that allows for analytical

comparisons to the URP

and mid-implementation-period course corrections if necessary.

See

64 FR 35731 (“The final rule calls for States to establish `reasonable progress goals,' expressed in deciviews, for each Class I area for the purpose of improving visibility on the haziest days and not allowing degradation on the clearest days over the period of each implementation plan or revision. The EPA believes that requiring States to establish such goals is consistent with section 169A of the CAA, which gives EPA broad authority to establish regulations to `ensure reasonable progress,' and with section 169B of the CAA, which calls for EPA to establish `criteria for measuring reasonable progress' toward the national goal.”).

Compare

40 CFR 51.308(f)(3)(iii)

with

40 CFR 51.308(d)(v).

Compare

40 CFR 51.308(f)(3)(ii)

with

40 CFR 51.308(d)(1)(ii).

40 CFR 51.308(g)(7), (h).

Other commenters stated that the proposed revisions to 40 CFR 51.308(f) were significant and unexplained departures from the EPA's prevailing interpretation of the reasonable progress factors and long-term strategy during the first implementation period. Several commenters contended that the revisions constituted an arbitrary and capricious change of position under the Supreme Court's recent decision in

Encino Motorcars, LLC

Navarro,

136 S. Ct. 2117 (2016). For example, one commenter contended that it was paradoxical for the long-term strategy to include the measures necessary to achieve the RPGs, while the RPGs were the predicted visibility outcome of implementing the emission controls in the long-term strategy. The commenter explained that this was inconsistent with the 1999 RHR, which made no mention of RPGs being set based on the predicted visibility improvement resulting from emission controls.

Another commenter contended that the EPA's proposed approach puts the cart before the horse because it does not allow states and RPOs to set visibility targets and then select the appropriate emission reduction measures to reach those targets. This would result in inefficiencies, according to the commenter, because states may have to secure additional emission reductions if their chosen strategies result in RPGs that fall short of the URP. The commenter explained that states would need more guidance regarding what types of sources and source categories to consider when seeking emission reductions. The commenter requested that the EPA develop a more logical process whereby states and RPOs would first develop visibility goals, allocate those goals among the states and then give states latitude to identify and assure emission reductions to achieve those visibility goals by using the four factors.

We disagree with these comments. They reflect a misunderstanding of the regional haze planning process generally followed by states. During the first implementation period, the RPOs conducted the regional-scale modeling used to establish their member states' RPGs. To conduct this modeling, the RPOs relied on 2018 emissions projections that reflected future application of reasonable controls for sources, including existing federal and state measures (the Clean Air Interstate Rule (CAIR), mobile source measures, etc.), anticipated BART controls and anticipated reasonable progress measures. The proposed and final revisions to 40 CFR 51.308(f) are fully consistent with this process. Under 40 CFR 51.308(f)(ii), states must develop their long-term strategies by identifying reasonable progress measures using the four factors and engaging in interstate consultation. Once their strategies have been developed, states with Class I areas must establish RPGs that reflect existing federal and state measures (the CSAPR, the Mercury and Air Toxics Standards, BART, mobile source measures, etc.) and the reasonable progress measures in the long-term strategy.

In contrast, the commenters have proposed a process in which states would either model their RPGs without fully developed emissions information or select their goals arbitrarily without any modeling at all. We rejected a similar approach in the 1999 RHR. In the 1997 proposal for the RHR, we proposed to establish presumptive reasonable progress targets of 1.0 deciview of improvement for the most impaired days and no degradation for the least impaired days and to require states to develop emission reduction strategies to achieve the reasonable progress targets.

In the 1999 RHR, we revised the proposal to eliminate the presumptive targets and instead required states “to determine the rate of progress for remedying existing impairment that is reasonable, taking into consideration the statutory factors.”

Importantly, we explained that, “[i]n considering whether reasonable progress will continue to be maintained, States will need to consider during each new SIP revision cycle whether additional control measures for improving visibility may be needed to make reasonable progress based on the statutory factors.”

Thus, the 1999 RHR was clear that states must determine what control measures are necessary to make reasonable progress by considering the four factors and then use this information to determine the rate of progress that is reasonable for each mandatory Class I Federal area.

62 FR 41146-47 (July 31, 1997).

64 FR 35731 (July 1, 1999).

Id.

at 35733.

In 2007, we provided guidance to the states on setting RPGs. There, we explained that the guidance's discussion of the four factors was “largely aimed at helping States apply these factors

in considering measures for point sources,

”

but that the factors could potentially be applied to sources other than point sources as well. We also described the intricate relationship between RPGs, BART, and the long-term strategy:

Guidance for Setting Reasonable Progress Goals Under the Regional Haze Program, at 1-3 (2007) (emphasis added).

The RPGs, the long-term strategy, and BART (or alternative measures in lieu of BART) are the three main elements of the regional haze SIPs that States are required to submit by December 17, 2007. The long-term strategy and BART emissions limitations or other alternative measures, including cap-and-trade programs or other economic incentive approaches, are inherently related to the RPG. The long-term strategy is the compilation of “enforceable emissions limitations, compliance schedules, and other measures as necessary to achieve the [RPGs],” and is the means through which the State ensures that its RPG will be met. BART emissions limits (or alternative measures in lieu of BART, such as the Clean Air Interstate Rule (CAIR)) are one set of measures that must be included in the SIP to ensure that an area makes reasonable progress toward the national goal, and the visibility improvement resulting from BART (or a BART alternative) is included in the development of the RPG.

Id.

at 1-4.

We note that the discussion previously refers to the long-term strategy as including the measures “necessary to achieve the RPG,” and that several provisions in the 1999 RHR were worded similarly.

We believe this type of language may have caused confusion among some of the commenters. This language does not mean that we intended states to develop their RPGs first and later adopt measures in the long-term strategy to achieve those RPGs. Rather, it merely acknowledges the fact that, because we intended states to develop their RPGs by modeling, among other things, the measures in the long-term strategy, the measures in the strategy are necessary to achieve the RPGs. For example, BART is one of the measures in the long-term strategy, and the discussion previously clearly states that “the visibility improvement resulting from BART (or a BART alternative)

is included in the development of the RPG.

” We proposed the structural revisions to 40 CFR 51.308(f) in part to eliminate this cart-before-the-horse ambiguity.

See, e.g.,

40 CFR 51.308(d)(3), (d)(3)(ii), (d)(3)(v)(C).

Later, the 2007 guidance clearly describes the goal-setting process as starting with the evaluation of control measures. First, we recommended that states “[i]dentify the key pollutants and sources and/or source categories that are contributing to visibility impairment at

each Class I area.”

Second, we recommended that states “[i]dentify the control measures and associated emission reductions that are expected to result from compliance with existing rules

and

other available measures for the sources and source categories that contribute significantly to visibility impairment.”

Third, and most importantly, we recommended that states “[d]etermine what additional control measures would be reasonable based on the statutory factors and other relevant factors for the sources and/or source categories you have identified.”

Finally, we recommended that states “[e]stimate through the use of air quality models the improvement in visibility that would result from implementation of the control measures you have found to be reasonable and compare this to the uniform rate of progress.”

In sum, “[t]he improvement in visibility resulting from implementation of the measures you have found to be reasonable . . . is the amount of progress that represents your RPG.”

This is the process that states used during the first implementation period,

see

the RTC at 2.2.1.2.6 for examples, and it is the same process that the states must follow under the final revisions to 40 CFR 51.308(f).

Id.

at 203.

Id.

(emphasis in the original).

Id.

at 2-4 (emphasis added).

While the guidance went on to note that states could attempt to “back out” the measures necessary to achieve the URP by modeling first and then considering the four factors to select appropriate measures,

few if any states chose this approach, likely because it was a more complicated way to achieve the same result as the recommended approach. Under either approach, states still had to use the four factors to justify whether the control measures necessary to achieve the URP were reasonable, whether achieving the URP was unreasonable and some of lesser set of measures was reasonable, or whether additional measures were reasonable. Moreover, the “back out” approach specified a concrete visibility target as its basis: The visibility that would be achieved by the URP at the end of the implementation period. The approach would be arbitrary and unworkable as a step in making the justifications just mentioned if the visibility target were chosen at random, as some commenters have requested. In sum, the EPA's proposed structural revisions are completely consistent with the 1999 RHR, our 2007 guidance and the planning process actually used by states during the first implementation period. For this reason, the Supreme Court's decision in

Encino Motorcars

is inapplicable.

Id.

at 2-3 to 2-4.

Another commenter contended that the EPA's proposed revisions failed to include a necessary step where states evaluate the control measures identified as necessary to make reasonable progress in light of the RPGs themselves. This commenter requested a mechanism whereby a state could determine that some of the initially evaluated control measures were unnecessary in light of the RPGs themselves. In particular, this commenter suggested that a state should be able to reject “costly” control measures if (1) the RPG for the most impaired days is on or below the URP line or (2) the RPGs are not “meaningfully” different than current visibility conditions.

We disagree that the states should be able to reevaluate whether a control measure is necessary to make reasonable progress based on the RPGs. The CAA requires states to determine what emission limitations, compliance schedules and other measures are necessary to make reasonable progress by considering the four factors. The CAA does not provide that states may then reject some control measures already determined to be reasonable if, in the aggregate, the controls are projected to result in too much or too little progress. Rather, the rate of progress that will be achieved by the emission reductions resulting from all reasonable control measures is, by definition, a reasonable rate of progress.

In regards to the commenter's first suggestion, if a state has reasonably selected a set of sources for analysis and has reasonably considered the four factors in determining what additional control measures are necessary to make reasonable progress, then the state's analytical obligations are complete if the resulting RPG for the most impaired days is below the URP line. The URP is not a safe harbor, however, and states may not subsequently reject control measures that they have already determined are reasonable. If a state's RPG for the most impaired days is above the URP line, then the state has an additional analytical obligation to ensure that no reasonable controls were left off the table.

The commenter's second suggestion, that states should be able to reject “costly” control measures if the RPG for the most impaired days is not “meaningfully” different than current visibility conditions, is counterintuitive and at odds with the purpose of the visibility program. In this situation, the state should take a second look to see whether more effective controls or additional measures are available and reasonable. Whether the state takes this second look or not, it may not abandon the controls it has already determined are reasonable based on the four factors. Regional haze is visibility impairment that is caused by the emission of air pollutants from numerous sources located over a wide geographic area. At any given Class I area, hundreds or even thousands of individual sources may contribute to regional haze. Thus, it would not be appropriate for a state to reject a control measure (or measures) because its effect on the RPG is subjectively assessed as not “meaningful.” Also, for Class I areas where visibility conditions are considerably worse than natural conditions because of continuing anthropogenic impairment from numerous sources, the logarithmic nature of the deciview index makes the effect of a control measure on the value of the RPG less than its effect would be if visibility conditions at the Class I area were better. Thus, if a state could reject a control measure based on its individual effect on the RPG, the state would be more likely to reject those measures that are necessary to make reasonable progress at the dirtiest Class I areas, which would thwart Congress' national goal.

One commenter contended that the proposed revisions would lead to disagreements among states because states might set different RPGs instead of working jointly toward the downwind state's goals. We disagree. Only downwind states set RPGs for their mandatory Class I Federal areas, so there is no situation in which there would be different goals for the same area.

Another commenter contended that the proposed revisions would force states to require controls even where visibility at a Class I area is already equivalent to or better than the visibility that represents the URP at the end of the implementation period. We agree that some states may end up establishing RPGs that exceed the URP, but as we explained previously in this document, the URP was never intended to be a safe harbor. In the 1999 RHR, we explained that “[i]f the State determines that the amount of progress identified through the analysis is reasonable based upon the statutory factors, the State should identify this amount of progress as its reasonable progress goal for the first long-term strategy, unless it determines that additional progress beyond this

amount is also reasonable. If the State determines that additional progress is reasonable based on the statutory factors, the State should adopt that amount of progress as its goal for the first long-term strategy.”

This approach is consistent with and advances the ultimate goal of section 169A: Remedying existing and preventing future visibility impairment. Congress required the EPA to promulgate regulations requiring reasonable progress toward that goal, and it would be antithetical to allow states to avoid implementing reasonable measures until and unless that goal is achieved.

64 FR 35732.

Other commenters were supportive of the proposed structural revisions intended to clarify the relationship between RPGs and long-term strategies. They explained that by reorienting these provisions to reflect the EPA's long-standing interpretation, the EPA was providing a clearer blueprint for states to follow in future implementation periods. These commenters also provided specific suggestions for how the EPA could further revise the proposed regulatory text for 40 CFR 51.308(f). Among other things, these commenters requested that the EPA include language in the regulations that would make it clear that a state's long-term strategy can include emission limits and other measures that cannot be installed by the end of an implementation period. As discussed earlier in Section IV.A of this document, we are modifying the language in 40 CFR 51.308(f)(2(i) and 51.308(f)(3)(i) to make this point clear. We have reviewed the other suggestions made by these commenters and do not believe that they are necessary, as discussed more fully in the RTC document available in the docket for this rulemaking.

We also received several comments regarding the obligations of upwind and downwind states. Some commenters supported the revisions that were intended to clarify that all states must conduct a four-factor analysis to determine what control measures are necessary to make reasonable progress at each mandatory Class I Federal area affected by emissions from the state. They explained that any other interpretation of the CAA's requirements would allow an upwind state to continue impairing downwind visibility without consequence, regardless of whether there were reasonable, cost-effective measures that would improve downwind visibility. Other commenters argued that upwind states should not have the same obligations as downwind states. One commenter asserted that, under the proposal, all states would be subject to the RHR for the very first time, regardless of whether they have a mandatory Class I Federal area or not. Another commenter contended that requiring upwind states to conduct four-factor analyses for downwind Class I areas was a new requirement that was not part of the 1999 RHR. This commenter acknowledged that upwind states must address downwind Class I areas where their emissions “may reasonably be anticipated to cause or contribute to any impairment of visibility” at the downwind area, but suggested that the proposed revisions use the language “may affect” instead. This commenter stated that the EPA's proposal did not define or quantify what the term “may affect” means.

Section 169A(b)(2) states that the EPA's regulations must: Require each applicable implementation plan for a State in which any [mandatory Class I Federal] area . . . is located (or a for a State the emissions from which may reasonably be anticipated to cause or contribute to any impairment of visibility in any such area) to contain such emission limits, schedules of compliance and other measures as may be necessary to make reasonable progress toward meeting the national goal.

Section 169A(g)(1) thus requires states to determine the measures necessary to make reasonable progress by considering the four factors, while section 169A(a)(1) defines Congress's national goal as preventing future and remedying existing anthropogenic visibility impairment in all Class I areas. Thus, Congress was clear that both downwind states (

i.e.,

“a State in which any [mandatory Class I Federal] area . . . is located) and upwind states (

i.e.,

“a State the emissions from which may reasonably be anticipated to cause or contribute to any impairment of visibility in any such area”) must revise their SIPs to include measures that will make reasonable progress at all affected Class I areas. Congress was also clear that states must determine the necessary measures and rate of progress that are reasonable by considering the four factors. Our proposed revisions to 40 CFR 51.308(f)(2) are in accord with this congressional mandate.

The commenter who suggested that our proposed revisions are expanding the scope of the RHR to all states for the first time is incorrect. The 1999 RHR applies to all states,

and all states submitted regional haze SIPs (or asked the EPA to promulgate a regional haze FIP on its behalf) during the first implementation period. As discussed later in this preamble, we are expanding the scope of the 1980 reasonably attributable visibility impairment regulations to all states for the first time, but the new reasonably attributable visibility impairment provisions only require state action upon receipt of a certification by a FLM. Historically, there have been very few FLM certifications requesting states to assess controls for a particular source or small group of sources.

40 CFR 51.300(b)(1)(i).

Finally, we note that the language “may affect” in 40 CFR 51.308(f)(2) was adapted from the 1999 RHR, which used the same term.

On July 8, 2016, we released draft guidance that discusses how states can determine which Class I areas they “may affect” and therefore must consider when selecting sources for inclusion in a four-factor analysis.

The draft guidance discusses various approaches that states used during the first implementation period, provides states with the flexibility to choose from among these approaches in the second implementation period, and recommends that states adopt “a conservative . . . approach to determining whether their sources may affect visibility at out-of-state Class I areas.”

We plan to finalize the draft guidance in the near future.

See

40 CFR 51.308(d)(3).

81 FR 44608 (July 8, 2016).

Draft Guidance on Progress Tracking Metrics, Long-term Strategies, Reasonable Progress Goals and Other Requirements for Regional Haze State Implementation Plans for the Second Implementation Period, at 57-58 (2016).

We also received comments on the proposed interstate consultation provisions in 40 CFR 51.308(f). A few commenters inquired whether proposed 40 CFR 51.308(f)(2)(iii)

would affect a substantive change from the existing consultation provisions in 40 CFR 51.308(d). One commenter stated that proposed 40 CFR 51.308(f)(2)(ii) would apparently require states to consider how other states calculated the URP, adopted emission reduction measures for sources and adopted any additional measures that may be needed to address state contributions. This commenter also argued that proposed 40 CFR 51.308(f)(2)(iii) would incentivize states not to agree with other states on coordinated emission management strategies because an agreement would create an enforceable obligation against the state. Another commenter stated that the EPA would need to coordinate and

mediate interstate consultations in order for them to prove successful.

As explained later in this document, the final rule includes a consolidation and resulting renumbering of some of the proposed provisions of 40 CFR 51.308(f)(2). This discussion refers specifically to either proposed or final section numbers to avoid confusion.

With one exception, we did not intend the proposed interstate consultation provisions to affect a substantive change from the existing provisions in the 1999 RHR. Under the proposed provisions, as under the 1999 RHR, states must consult to develop coordinated emission management strategies, demonstrate that their SIPs contain all agreed-upon emission reduction measures, and document disagreements so that the EPA can properly evaluate whether each state's implementation plan provides for reasonable progress toward the national goal. We also proposed a new requirement, in 40 CFR 51.308(f)(2)(ii), that states must consider the control strategies being adopted by other states when conducting their own four-factor analyses. The purpose of this provision was to ensure that if one state had identified a control measure as being reasonable for a source or group of sources to improve visibility at a Class I area, then other states that affect that Class I area would be required to consider that control measure for their own sources, to the extent that the sources share similar characteristics. However, in reviewing proposed 40 CFR 51.308(f)(2)(ii), we realized that it contains extraneous language that has led to confusion among some of the commenters. We discuss this issue in more depth, and other changes being made to the consultation provisions, in the following section.

In regard to the commenter's concern that the consultation provisions will incentivize states to avoid entering into agreements with each other to avoid enforceable obligations, we disagree. States largely worked cooperatively to develop coordinated emission management strategies during the first implementation period, and we expect that they will do so again. If a state believes that additional controls from sources in another state or states are necessary to make reasonable progress at a Class I area, then the state should document the disagreement to assist the EPA in determining whether the other state's SIP is inadequate. Moreover, even if states were to avoid entering into agreements for the purpose of avoiding enforceable obligations under 40 CFR 51.308(f)(iii), this would not absolve the states of their independent obligation to include in their SIPs enforceable emission limits and other measures that are necessary to make reasonable progress at all affected Class I areas, as determined by considering the four factors. Finally, we do not believe that the EPA needs to coordinate or mediate interstate consultations. During the first implementation period, states consulted one-on-one and through the RPO process without EPA oversight, and we expect this process to work going forward as well.

3. Final Rule

We are finalizing the revisions to 40 CFR 51.308(f) that were intended to clarify the relationship between RPGs and long-term strategies and the obligations of upwind and downwind states largely as proposed. However, we are making several changes to the provisions in 40 CFR 51.308(f)(2) governing long-term strategies to simplify these provisions, enhance clarity and eliminate superfluous regulatory text.

In 40 CFR 51.308(f)(2), we are revising the requirement that states must include in their long-term strategies “the enforceable emissions limitations, compliance schedules, and other measures that are necessary to achieve reasonable progress” to read “make reasonable progress” instead. This change is to maintain consistency with the language in CAA section 169A(b)(2).

In 40 CFR 51.308(f)(2)(i), we are making two minor changes. First, we are revising the beginning of the first sentence to read, “[t]he State must evaluate and determine the emission reduction measures that are necessary to make reasonable progress by considering” the four factors. We believe that this formulation is clearer than the language in the proposal and more consistent with the language of the CAA. Second, we are revising the second sentence, and splitting it into two separate sentences, to make it clear that states must consider anthropogenic sources of visibility impairment when conducting their four-factor analyses, not natural sources, and that anthropogenic sources can include mobile and area sources in addition to major and minor stationary sources. As mentioned earlier, we are also adding a sentence to 40 CFR 51.308(f)(2)(i) regarding the consideration of emission controls that cannot reasonably be installed prior to the end of the implementation period.

We are removing proposed 40 CFR 51.308(f)(2)(ii) in these final revisions, which required states to consider the URP, the emission reduction measures identified under 40 CFR 51.308(f)(2)(i), and measures being adopted by contributing states under 40 CFR 51.308(f)(2)(iii) when developing their long-term strategies. States are already required to consider the URP under 40 CFR 51.308(f)(3)(ii) when establishing their RPGs. Moreover, it is duplicative to require states to consider the emission reduction measures identified under 40 CFR 51.308(f)(2)(i) a second time. As discussed in the following paragraph, we are moving the third requirement in proposed 40 CFR 51.308(f)(2)(ii) to the interstate consultation provisions.

We are changing proposed 40 CFR 51.308(f)(2)(iii), regarding interstate consultations, to be 40 CFR 51.308(f)(2)(ii) and making several changes. First, we are removing the distinction between contributing states and states affected by contributing states because the substance of the two provisions was essentially the same. The final revisions include a single provision requiring each state to consult with the other states that are reasonably anticipated to contribute to visibility impairment in a mandatory Class I Federal area to develop coordinated emission management strategies. Identification of the other states should occur as part of a regional planning process. Second, we are revising the language that required states to obtain either their “share of the emission reductions needed to provide for reasonable progress” or “all measures needed to achieve its apportionment of emission reduction obligations” depending on whether the state was a contributing state or a state affected by contributing states. Most states are both contributing states and states affected by contributing states, so these variations in wording could be viewed as creating two distinct obligations. Now, each state must demonstrate that it has included in its long-term strategy “all measures agreed to during state-to-state consultations or a regional planning process, or measures that will provide equivalent visibility improvement.” Third, as discussed previously, we have moved the requirement that states consider the emission reduction measures other states have identified as being necessary to make reasonable progress from proposed 40 CFR 51.308(f)(2)(ii), which accordingly has been eliminated, to the interstate consultation provisions (now numbered as 40 CFR 51.308(f)(2)(ii)) because it is a more logical place for it. We have also revised the wording of this provision to eliminate the ambiguity in the proposed language noted by commenters regarding “additional measures being adopted” by other states. Under this provision, states must consider whether the emission reduction measures other states have identified by other States for their sources as being necessary to make reasonable progress in the mandatory Class I Federal area. This consideration

is appropriate especially when the sources are of a similar type and have similar emissions profiles and visibility impacts.

We are changing proposed 40 CFR 51.308(f)(2)(iv), regarding documentation requirements, to be 40 CFR 51.308(f)(2)(iii) and making a few minor changes. First, we are revising the first sentence to require the states to “document the technical basis, including modeling, monitoring, cost, engineering, and emissions information, on which the State is relying to determine the emission reduction measures that are necessary to make reasonable progress in each mandatory Class I area it affects.” The proposed language referred to “information on the factors listed in (f)(2)(i) and modeling, monitoring, and emissions information,” but we believe this language was confusing because it suggested that information on the four factors was something distinct from modeling, monitoring and emissions information. The purpose of this provision is to require states to document all of the information on which they rely to develop their long-term strategies, which will primarily be information used to conduct the four-factor analysis. Therefore, in addition to modeling, monitoring and emissions information, we are making it explicit that states must also submit the cost and engineering information on which they are relying to evaluate the costs of compliance, the time necessary for compliance, the energy and non-air quality impacts of compliance and the remaining useful lives of sources.

We are removing proposed 40 CFR 51.308(f)(2)(v), which required states to identify the anthropogenic sources of visibility impairment analyzed using the four factors and the criteria used to select sources for analysis, because 40 CFR 51.308(f)(2)(i) as finalized already includes these requirements.

Finally, we are changing proposed 40 CFR 51.308(f)(2)(vi) to be 40 CFR 51.308(f)(2)(iv) and making a few changes. We are revising the first sentence of this provision to clarify that the enumerated factors are additional to the factors states must consider in 40 CFR 51.308(f)(2)(i). We are also removing proposed 40 CFR 51.308(f)(2)(vi)(C) and (F) because they are duplicative requirements. These provisions required states to consider the emission limitations and schedules for compliance to achieve the RPG and the enforceability of emission limitations and control measures. Section 40 CFR 51.308(f)(2) already requires states to include enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress in their long-term strategies. Section IV.G of this document discusses revisions we are making to the additional factor regarding basic smoke management practices and smoke management programs.

D. Other Clarifications and Changes to Requirements for Periodic Comprehensive Revisions of Implementation Plans

The following clarifications and changes were also proposed to be included in the revised 40 CFR 51.308(f). A summary of each proposed clarifying change, a synopsis of the final rule, and a discussion of comments received and EPA's responses are given later.

The URP line starts at 2000-2004, for every implementation period.

1. Summary of Proposal

The 1999 RHR's text of 40 CFR 51.308(d)(1)(i)(B) contains a discussion of how states must analyze and determine “the rate of progress needed to attain natural visibility conditions by the year 2064.” This rate has commonly been called the “uniform rate of progress” or URP as well as “the glidepath.” The 1999 RHR's text of 40 CFR 51.308(f), which indicates that states must evaluate and reassess all elements required by 40 CFR 51.308(d), requires states to evaluate and reassess the URP in the second and subsequent implementation periods. We explained in the proposal that 40 CFR 51.308(d) is not perfectly clear as to whether the URP line for the second or later implementation periods must always start in the baseline period of 2000-2004, or whether the state must (or may) recalculate the starting point of the URP line based on data from the most recent 5-year period during each successive regional haze SIP revision.

We also explained that although the regulations make clear that the endpoint of the URP line should be set based on attainment of the natural visibility condition for the 20 percent most impaired days in 2064, the 1999 RHR does not specify an exact date in 2064 for this element.

The preamble to the 1999 RHR provides an example explaining how a state would determine the 2028 point on the URP line. 64 FR at 35746, n. 113. In this example, the URP line for the second implementation period starts at 2000-2004.

To ensure consistent understanding of how the URP analysis must be done, the EPA proposed rule revisions in 40 CFR 51.308(f)(1)(i) and (vi) that would make it explicit that in every implementation period, the URP line for each Class I area is to be drawn starting on December 31, 2004, at the value of the 2000-2004 baseline visibility conditions for the 20 percent most impaired days, and ending at the value of natural visibility conditions on December 31, 2064. Specifying that the 5-year average baseline visibility conditions are associated with the date of December 31, 2004, and that natural visibility conditions are associated with the date of December 31, 2064, also clarifies that the period of time between the baseline period and natural visibility conditions, which is needed for determining the URP (deciviews/year) is 60 years.

Along with the clarification that the baseline period remains 2000-2004 for subsequent implementation periods, the EPA also proposed clarifications in 40 CFR 51.308(f)(1)(i) regarding how states treat Class I areas without available monitoring data or Class I areas with incomplete monitoring data, as follows: If Class I areas do not have monitoring data for the baseline period, data from representative sites should be used; if baseline monitoring data are incomplete, states should use the 5 complete years closest to the baseline period. We proposed to add this provision to remove any uncertainty about how an issue of data incompleteness should be addressed in a SIP.

Finally, we proposed language in 40 CFR 51.308(f)(3)(i) and an accompanying definition of “end of the applicable implementation period” in 40 CFR 51.301 to make clear that RPGs are to address the period extending to the end of the year of the due date of the next periodic comprehensive SIP revision.

2. Comments and Responses

Some commenters were supportive of EPA's proposal to have the URP line start at 2000-2004 for every implementation period, although some asked for the option of recalculating the URP for the start of each implementation period based on how much further progress is needed to reach natural conditions given the progress already achieved. Other commenters did not agree with EPA's proposal and instead supported a revision to the regulations that would require states to reset the URP at current visibility conditions during each periodic review, provided those visibility conditions are better than during the baseline. Taking into account past improvements in visibility that were in excess of the URP in this way would result in a lower-lying URP line for successive planning periods. This could change the comparison of the RPG to the URP line, and trigger the

requirement of 40 CFR 51.308(f)(3)(ii) to show that there are no additional measures that would be reasonable to include in the long-term strategy, when it would not be triggered if the start of the URP line had been kept at the 2000-2004 period.

As explained in the 1999 RHR, the consideration of the improvement in visibility represented by the URP and the measures necessary to attain that level of improvement is an analytical requirement. In the 1999 RHR, EPA adopted this required analysis in lieu of establishing presumptive reasonable progress targets, in part to provide equity between the goals set for the Class I areas in the more impaired eastern portion of the country as compared to the areas in the western portion. The URP analysis also helps to provide transparency to the overall regional haze SIP planning process, in part by requiring states to compare their RPGs to the rate of progress represented by the URP at each Class I areas. Neither of these goals would be served by allowing states to adopt differing approaches to the calculation of the URP.

We have considered the comments suggesting that the URP be redrawn during each successive planning period. Although such an approach is apparently intended by commenters to maintain pressure on the states to adopt more comprehensive and effective reasonable progress strategies, it is not clear that this approach would in fact achieve that outcome because it may create disincentives for states to take aggressive action during the first few planning periods. This is because resetting the URP would make it more likely that a state that has taken early and aggressive action to improve visibility would become subject to the enhanced analytical requirement of 40 CFR 51.308(f)(3)(ii), thus generating a possible disincentive for continued progress.

Because we have concluded that our proposed approach of starting the URP for every implementation period at 2000-2004 will result in the most equitable and transparent process and provide the strongest incentive for continued progress toward achieving natural visibility conditions, we are finalizing that approach with no changes to 40 CFR 51.308(f)(1)(i) or (vi).

3. Final Rule

The EPA is finalizing all of the previously described rule text without any changes from the proposal.

The long-term strategy and the RPGs must provide for an improvement in visibility for the most impaired days and ensure no degradation for the clearest days.

1. Summary of Proposal

Section 169A of the CAA requires a SIP to not only reduce existing visibility impairment but also to prevent future impairment. As part of meeting the goal of preventing future visibility impairment, 40 CFR 51.308(d)(1) of the 1999 RHR requires a state to establish RPGs that ensure no degradation in visibility for the least impaired days over the period of the implementation plan. This text is ambiguous, however, as to whether “the period of the implementation plan” refers to the entire period since the baseline period of 2000-2004 or to the specific implementation period addressed by the periodic SIP revision. The proposal noted that a table in the preamble to the 1999 RHR summarizing certain requirements indicated that the 2000-2004 period would be used for “tracking visibility improvement.”

To provide further clarity on this issue, we proposed new rule text in revised 40 CFR 51.308(f)(3)(i) that would make clear that the requirement is for a state to establish an RPG for the 20 percent clearest days in each periodic review that ensures that there is no deterioration in visibility on the 20 percent clearest days as compared to the baseline period of 2000-2004. We note that while 40 CFR 308(d)(1) of the 1999 RHR expresses the requirement of no degradation in visibility in terms of the RPG for the 20 percent clearest days, this requirement comes into play as a factor in what emission sources are subject to additional control measures in the long-term strategy, because this RPG is the projected result of implementing the long-term strategy. In other words, a state must adopt a long-term strategy that includes the necessary measures to ensure that the expected visibility on the 20 percent clearest days at the end of the planning period, as represented by the RPG for these days, will not deteriorate as compared to the visibility condition for these days in 2000-2004.The rule text we proposed for 40 CFR 308(f)(3)(i) made this connection explicit by saying that the long-term strategy and the RPG must provide for no degradation.

64 FR 35730.

2. Comments and Responses

The EPA received comments both in support of, and raising concerns with, the proposed changes. The commenters opposed to our proposal preferred that when a state documents that the RPG for the 20 percent clearest days (

i.e.,

the projected visibility condition on the clearest days as of the end of the given implementation period) shows no degradation, the benchmark for that comparison should be the lowest measured impairment of either the baseline period or current conditions reported in any progress report or comprehensive periodic revision for the clearest days. The approach recommended by the commenter would mean that the benchmark for the no degradation comparison would ratchet down over time.

One commenter pointed out that as proposed, 40 CFR 308(f)(3)(i) addressed not just the requirement for no degradation for the clearest days but also the requirement that there be an improvement for the most impaired days. This commenter noted that the relevant sentence of 40 CFR 308(f)(3)(i) could be interpreted to mean that the baseline period of 2000-2004 is the benchmark for determining if the long-term strategy and RPG for the most impaired days provides for an improvement.

The commenter said that the final rule should provide that the benchmark for the improvement requirement should be the lowest measured impairment of either the baseline period or current conditions reported in any progress report or comprehensive periodic revision for the most impaired days. The approach recommended by the commenter would mean that the benchmark for the improvement comparison would ratchet down over time.

The relevant sentence in the rule reads, “The long-term strategy and reasonable progress goals must provide for an improvement in visibility for the most impaired days and ensure no degradation in visibility for the clearest days since the baseline period.” The concluding phrase “since the baseline period” can be taken to apply to only the clearest days, or to both the most impaired days and the clearest days.

We are finalizing our proposal to clarify that the benchmark for the requirement for no degradation on the 20 percent clearest days is the 2000-2004 baseline visibility condition. Further, we are clarifying that the baseline visibility condition for the 20 percent most impaired days is also the benchmark for the requirement that the long-term strategy and RPGs provide for an improvement for the most impaired days. We are taking this approach in the final rule for several reasons.

Visibility on the clearest days has been improving since the 2000-2004 period in most Class I areas, generally tracking the improvements seen on the 20 percent haziest and 20 percent most

impaired days.

100

We expect that it will continue to be the case that emission reduction measures that provide for reasonable progress on the 20 percent most impaired days will also have benefits on the clearest days. Thus, we expect that there will be a continuing improvement on the clearest days regardless of the benchmark selected, even if the rule did not contain any requirement for no degradation on the clearest days. Even so, we believe that the no degradation requirement with the 2000-2004 visibility condition as the benchmark is an appropriate backstop in the rule that will continue to require states to consider additional measures in the event that measures adopted to improve visibility on the most impaired days are insufficient to protect visibility on the clearest days.

100

The RTC contains graphics illustrating these improvement trends. The only situations in which there has been degradation since 2000-2004 are at a few Class I areas in the Virgin Islands and Alaska where sea salt particles significantly contribute to light extinction on the clearest days and concentrations of such particles on those days have increased over this period.

We are not adopting the approach of ratcheting down the benchmark for the no degradation requirement. If we were to do this, it might lead to unreasonable outcomes in some cases. Available air quality modeling approaches for forecasting visibility conditions are at present more uncertain when predicting low concentrations of visibility-impairing pollution than when predicting higher concentrations, making comparisons of two “clean” scenarios more uncertain. Such comparisons could become required for many areas and have critical implications for SIP approvals. Errors in such comparisons due to modeling system errors might lead to inappropriate SIP disapprovals if the benchmark for the no degradation requirement continually ratcheted down as progress is made. Another consideration is that even with a 5-year averaging approach, transient natural phenomena might cause a temporary improvement in visibility on the clearest days entirely unrelated to the content and implementation of states' long term strategies, which would permanently reduce the benchmark if the ratcheting approach were followed. It might then be very difficult or unreasonable for a state in subsequent periods to show no degradation relative to this lower benchmark given that on the clearest days influences from anthropogenic sources will be relatively small. Finally, we believe that consistency between the benchmark for the no degradation test and the starting point for the URP, across Class I areas in a given implementation period and across implementation periods, will aid public understanding and participation in SIP development. For these reasons, we are finalizing our proposal on this aspect of the RHR.

In addition, we are finalizing wording in 40 CFR 308(f)(3)(i) that makes it clear that the baseline condition in 2000-2004 is also the benchmark for determining whether the long-term strategy and RPGs provide for an improvement in visibility for the most impaired days, but repeating the reference to this baseline so that it links unambiguously to that requirement as well as to the no degradation requirement. We recognize that since 2000-2004 there have been widespread improvements in visibility on the most impaired days and that this already accomplished improvement has created a “cushion” for a comparison to check that the RPG for the end of a future implementation period shows improvement. However, we disagree with the commenter's suggestion that the benchmark for the improvement requirement should ratchet down over time, for similar but not entirely identical reasons that we disagree regarding the no degradation requirement. The advantage of consistency to public understanding applies to the improvement requirement as well as to the no degradation requirement. While the problem of modeling uncertainty applies less to the most impaired days at this stage of the regional haze program, in later periods the most impaired days will be clearer than they are now and the difficulty of distinguishing differences may apply more strongly. Also, we are mindful of the potential for reducing incentives for states to take action during the first few planning periods. With the 2000-2004 period as the benchmark for the no degradation requirement, a state has an incentive to take early action to improve the clearest days because this will create a safety margin in case later developments outside the state's control cause an increase in impairment on these days. Ratcheting down the baseline for the no degradation requirement would remove this incentive for continued progress because it would never be possible for a state to create a safety margin.

However, the use of the baseline period as the benchmark for the no degradation and improvement requirements does not mean that states are free to simply allow visibility levels to return to what they were in the baseline period, or to allow for degradation in visibility as compared to current conditions. If a state were to set an RPG that reflects a forecast of degradation during a particular period, the adequacy of the SIP would need to be carefully assessed. In this situation, additional measures may be necessary to ensure reasonable progress, depending on the underlying explanation for the forecasted degradation. It may be that a state would be able to show that any forecasted degradation is attributable to causes other than deficiencies in its long-term strategy, but such a demonstration would need to be carefully assessed. We note that for at least the next planning period or two, the re

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