Air Plan Approval; OR; Regional Haze Plan for the Second Implementation Period

#  Air Plan Approval; OR; Regional Haze Plan for the Second Implementation Period

**AGENCY:**

Environmental Protection Agency (EPA).

**ACTION:**

Proposed rule.

**SUMMARY:**

The Environmental Protection Agency (EPA) is proposing to approve the regional haze state implementation plan revision submitted by Oregon on April 29, 2022, as supplemented on November 22, 2023, as satisfying applicable requirements under the  Clean Air Act and the EPA's Regional Haze Rule for the program's second implementation period. The Oregon submission addressed the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The Oregon submission also addressed other applicable requirements for the second implementation period of the regional haze program. Upon final action, the Oregon submission will become part of the Oregon SIP.

**DATES:**

Written comments must be received on or before March 25, 2024.

**ADDRESSES:**

Submit your comments, identified by Docket ID No. EPA-R10-OAR-2023-0600 at *https://www.regulations.gov.* For comments submitted at regulations.gov, follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from regulations.gov. For either manner of submission, the EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be confidential business information or other information the disclosure of which is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( *i.e.,* on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section. For the full EPA public comment policy, information about confidential business information or multimedia submissions, and general guidance on making effective comments, please visit *https://www.epa.gov/dockets/commenting-epa-dockets.*

**FOR FURTHER INFORMATION CONTACT:**

Jeff Hunt, EPA Region 10, 1200 Sixth Avenue, Suite 155, Seattle, WA 98101, at (206) 553-6357 or *[email protected].*

**SUPPLEMENTARY INFORMATION:**

Throughout this document, the use of “we” and “our” means the EPA.

**Table of Contents**

I. Proposed Action

II. Background and Requirements for Regional Haze Plans

A. Regional Haze Background

B. Roles of Agencies in Addressing Regional Haze

III. Requirements for Regional Haze Plans for the Second Implementation Period

A. Identification of Class I Areas

B. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress

C. Long-Term Strategy for Regional Haze

D. Reasonable Progress Goals

E. Monitoring Strategy and Other State Implementation Plan Requirements

F. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals

G. Requirements for State and Federal Land Manager Coordination

IV. The EPA's Evaluation of the Oregon Regional Haze Submission for the Second Implementation Period

A. Background on the Oregon First Implementation Period SIP Submission

B. The Oregon Second Implementation Period SIP Submission and the EPA's Evaluation

C. Identification of Class I Areas

D. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress

E. Long-Term Strategy for Regional Haze

a. The Oregon Long-Term Strategy

b. The EPA's Evaluation of the Oregon Long-Term Strategy

c. Additional Long-Term Strategy Requirements

F. Reasonable Progress Goals

G. Monitoring Strategy and Other Implementation Plan Requirements

H. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals

I. Requirements for State and Federal Land Manager Coordination

V. Proposed Action

VI. Incorporation by Reference

VII. Statutory and Executive Order Reviews

**I. Proposed Action**

On April 29, 2022 and November 22, 2023, Oregon submitted a state implementation plan (SIP) revision and supplement to address regional haze for the second implementation period. Oregon made the submissions to satisfy the Clean Air Act regional haze program requirements pursuant to Clean Air Act sections 169A and 169B and the EPA's implementing regulations in the Code of Federal Regulations (CFR) at 40 CFR 51.308. The EPA is proposing to find that the Oregon submissions meet the applicable statutory and regulatory requirements and thus we are proposing to approve the submissions into the SIP. We are also proposing to approve, and incorporate by reference into the Oregon SIP at 40 CFR part 52, subpart MM, specific regulatory provisions and source-specific requirements included in the submissions. These provisions are detailed in section V. of this preamble.

**II. Background and Requirements for Regional Haze Plans**

**A. Regional Haze Background**

In the 1977 Clean Air Act Amendments, Congress created a program [^1] to protect visibility in the nation's mandatory class I Federal areas, which include certain national parks and wilderness areas. [^2] Congress established 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.” [^3] Congress further directed the EPA to promulgate regulations to assure reasonable progress toward meeting this national goal. [^4] On December 2, 1980, the EPA promulgated regulations to address visibility impairment in mandatory class I Federal areas (hereinafter referred to as “Class I areas”) that is “reasonably attributable” to a single source or small group of sources. [^5] These regulations, codified at 40 CFR 51.300 through 51.307, represented the first phase of the EPA's efforts to address visibility impairment. In 1990, Congress added section 169B to the Clean Air Act to further address visibility impairment, specifically, impairment from regional haze. The EPA subsequently promulgated the Regional Haze Rule on July 1, 1999 (64 FR 35714), codified at 40 CFR 51.308. [^6] These regional haze regulations are a central component of the EPA's comprehensive visibility protection program for Class I areas.

[^1] Clean Air Act section 169A.

[^2] Areas statutorily 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. Clean Air Act 162(a). There are 156 mandatory Class I areas. The list of areas to which the visibility protection program applies is set forth in 40 CFR part 81, subpart D.

[^3] Clean Air Act section 169A(a)(1).

[^4] Clean Air Act section 169A(a)(4).

[^5] 45 FR 80084, December 2, 1980.

[^6] In addition to the generally applicable regional haze provisions at 40 CFR 51.308, the EPA also promulgated regulations specific to addressing regional haze visibility impairment in Class I areas on the Colorado Plateau at 40 CFR 51.309. The latter regulations are applicable only for specific jurisdictions' regional haze plans submitted no later than December 17, 2007, and thus are not relevant here.

Regional haze is visibility impairment that is produced by a multitude of anthropogenic sources and activities which are located across a broad geographic area and that emit pollutants that impair visibility. Visibility impairing pollutants include fine and coarse particulate matter (PM) ( *e.g.,* sulfates, nitrates, organic carbon, elemental carbon, and soil dust) and  their precursors ( *e.g.,* sulfur dioxide (SO <sub>2</sub> ), nitrogen oxides (NO <sub>X</sub> ), and, in some cases, volatile organic compounds (VOC) and ammonia (NH <sub>3</sub> )). Fine particle precursors react in the atmosphere to form fine particulate matter (PM <sub>2.5</sub> ), which impairs visibility by scattering and absorbing light. Visibility impairment reduces the perception of clarity and color, as well as visible distance. [^7]

[^7] There are several ways to measure the amount of visibility impairment, *i.e.,* haze. One such measurement is the deciview, which is the principal metric used by the Regional Haze Rule. Under many circumstances, a change in one deciview will be perceived by the human eye to be the same on both clear and hazy days. The deciview is unitless. It is proportional to the logarithm of the atmospheric extinction of light, which is the perceived dimming of light due to its being scattered and absorbed as it passes through the atmosphere. Atmospheric light extinction (b [^ext] ) is a metric used to for expressing visibility and is measured in inverse megameters (Mm <sub>−1</sub> ). The EPA's Guidance on Regional Haze State Implementation Plans for the Second Implementation Period (“2019 Guidance”) offers the flexibility for the use of light extinction in certain cases. Light extinction can be simpler to use in calculations than deciviews, since it is not a logarithmic function. See, *e.g.,* 2019 Guidance at 16, 19, *https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period.* The EPA Office of Air Quality Planning and Standards, Research Triangle Park (August 20, 2019). The formula for the deciview is 10 ln (b [^ext] )/10 Mm <sub>−1</sub> ). 40 CFR 51.301.

To address regional haze visibility impairment, the 1999 Regional Haze Rule established an iterative planning process that requires both states in which Class I areas are located and states “the emissions from which may reasonably be anticipated to cause or contribute to any impairment of visibility” in a Class I area to periodically submit SIP revisions to address such impairment. [^8] Under the Clean Air Act, each SIP submission must contain “a long-term (ten to fifteen years) strategy for making reasonable progress toward meeting the national goal.” [^9] The initial round of SIP submissions also had to address the statutory requirement that certain older, larger sources of visibility impairing pollutants install and operate the best available retrofit technology (BART). [^10] States' first regional haze SIPs were due by December 17, 2007, [^11] with subsequent SIP submissions containing updated long-term strategies originally due July 31, 2018, and every ten years thereafter. [^12] The EPA established in the 1999 Regional Haze Rule that all states either have Class I areas within their borders or “contain sources whose emissions are reasonably anticipated to contribute to regional haze in a Class I area”; therefore, all states must submit regional haze SIPs. [^13]

[^8] Clean Air Act section 169A(b)(2). See also 40 CFR 51.308(b), (f) (establishing submission dates for iterative regional haze SIP revisions (64 FR 35714, 35768, July 1, 1999). The Regional Haze Rule expresses the statutory requirement for states to submit plans addressing out-of-state Class I areas by providing that states must address visibility impairment “in each mandatory Class I Federal area located outside the State that may be affected by emissions from within the State.” 40 CFR 51.308(d), (f).

[^9] Clean Air Act section 169A(b)(2)(B).

[^10] Clean Air Act section 169A(b)(2)(A); 40 CFR 51.308(d), (e).

[^11] 40 CFR 51.308(b).

[^12] 64 FR 35714, 35768, July 1, 1999.

[^13] 64 FR 35714, 35721, July 1, 1999. In addition to each of the fifty states, the EPA also concluded that the Virgin Islands and District of Columbia must also submit regional haze SIPs because they either contain a Class I area or contain sources whose emissions are reasonably anticipated to contribute regional haze in a Class I area. See 40 CFR 51.300(b), (d)(3).

Much of the focus in the first implementation period of the regional haze program, which ran from 2007 through 2018, was on satisfying states' BART obligations. First implementation period SIPs were additionally required to contain long-term strategies for making reasonable progress toward the national visibility goal, of which BART is one component. The core required elements for the first implementation period SIPs (other than BART) are laid out in 40 CFR 51.308(d). Those provisions required that states containing Class I areas establish reasonable progress goals that are measured in deciviews and reflect the anticipated visibility conditions at the end of the implementation period including from implementation of states' long-term strategies. The first planning period reasonable progress goals were required to provide for an improvement in visibility for the most impaired days over the period of the implementation plan and ensure no degradation in visibility for the least impaired days over the same period. In establishing the reasonable progress goals for any Class I area in a state, the state was required to consider four statutory factors: the costs of compliance, the time necessary for compliance, the energy and non-air quality environmental impacts of compliance, and the remaining useful life of any potentially affected sources. [^14]

[^14] Clean Air Act section 169A(g)(1); 40 CFR 51.308(d)(1).

States were also required to calculate baseline (using the five year period of 2000-2004) and natural visibility conditions ( *i.e.,* visibility conditions without anthropogenic visibility impairment) for each Class I area, and to calculate the linear rate of progress needed to attain natural visibility conditions, assuming a starting point of baseline visibility conditions in 2004 and ending with natural conditions in 2064. This linear interpolation is known as the “uniform rate of progress” and is used as a tracking metric to help states assess the amount of progress they are making towards the national visibility goal over time in each Class I area. [^15] The 1999 Regional Haze Rule also provided that states' long-term strategies must include the “enforceable emissions limitations, compliance, schedules, and other measures as necessary to achieve the reasonable progress goals.” [^16] In establishing their long-term strategies, states are required to consult with other states that also contribute to visibility impairment in a given Class I area and include all measures necessary to obtain their shares of the emission reductions needed to meet the reasonable progress goals. [^17] The 1999 Regional Haze Rule also contains seven additional factors states must consider in formulating their long-term strategies, [^18] as well as provisions governing monitoring and other implementation plan requirements. [^19] Finally, the 1999 Regional Haze Rule required states to submit periodic progress reports—SIP revisions due every five years that contain information on states' implementation of their regional haze plans and an assessment of whether anything additional is needed to make reasonable progress [^20] —and to consult with the Federal Land Manager(s) [^21] responsible for each Class I area  according to the requirements in Clean Air Act 169A(d) and 40 CFR 51.308(i).

[^15] 40 CFR 51.308(d)(1)(i)(B), (d)(2). The EPA established the uniform rate of progress framework in the 1999 Regional Haze Rule to provide “an equitable analytical approach” to assessing the rate of visibility improvement at Class I areas across the country. The start point for the uniform rate of progress analysis is 2004 and the endpoint was calculated based on the amount of visibility improvement that was anticipated to result from implementation of existing Clean Air Act programs over the period from the mid-1990s to approximately 2005. Assuming this rate of progress would continue into the future, the EPA determined that natural visibility conditions would be reached in 60 years, or 2064 (60 years from the baseline starting point of 2004). However, the EPA did not establish 2064 as the year by which the national goal *must* be reached. 64 FR 35714, 35731-32, July 1, 1999. That is, the uniform rate of progress and the 2064 date are not enforceable targets, but are rather tools that “allow for analytical comparisons between the rate of progress that would be achieved by the state's chosen set of control measures and the [uniform rate of progress] URP.” (82 FR 3078, 3084, January 10, 2017).

[^16] 40 CFR 51.308(d)(3).

[^17] 40 CFR 51.308(d)(3)(i), (ii).

[^18] 40 CFR 51.308(d)(3)(v).

[^19] 40 CFR 51.308(d)(4).

[^20] See 40 CFR 51.308(g), and (h).

[^21] The EPA's regulations define “Federal Land Manager” as “the Secretary of the department with authority over the Federal Class I area (or the Secretary's designee) or, with respect to Roosevelt-Campobello International Park, the Chairman of the Roosevelt-Campobello International Park Commission.” 40 CFR 51.301.

On January 10, 2017, the EPA promulgated revisions to the Regional Haze Rule that apply for the second and subsequent implementation periods (82 FR 3078). The 2017 rulemaking made several changes to the requirements for regional haze SIPs to clarify States' obligations and streamline certain regional haze requirements. The revisions to the regional haze program for the second and subsequent implementation periods focused on the requirement that States' SIPs contain long-term strategies for making reasonable progress towards the national visibility goal. The reasonable progress requirements as revised in the 2017 rulemaking (referred to here as the 2017 Regional Haze Rule Revisions) are codified at 40 CFR 51.308(f). Among other changes, the 2017 Regional Haze Rule Revisions adjusted the deadline for States to submit their second implementation period SIPs from July 31, 2018, to July 31, 2021, clarified the order of analysis and the relationship between reasonable progress goals and the long-term strategy, and focused on making visibility improvements on the days with the most *anthropogenic* visibility impairment, as opposed to the days with the most visibility impairment overall. The EPA also revised requirements of the visibility protection program related to periodic progress reports and Federal Land Manager consultation. The specific requirements applicable to second implementation period regional haze SIP submissions are addressed in detail in the following paragraphs.

The EPA provided guidance to the states for their second implementation period SIP submissions in the preamble to the 2017 Regional Haze Rule Revisions as well as in subsequent, stand-alone guidance documents. In August 2019, the EPA issued “Guidance on Regional Haze State Implementation Plans for the Second Implementation Period” (“2019 Guidance”). [^22] On July 8, 2021, the EPA issued a memorandum containing “Clarifications Regarding Regional Haze State Implementation Plans for the Second Implementation Period” (“2021 Clarifications Memo”). [^23] Additionally, the EPA further clarified the recommended procedures for processing ambient visibility data and optionally adjusting the uniform rate of progress to account for international anthropogenic and prescribed fire impacts in two technical guidance documents: the December 2018 “Technical Guidance on Tracking Visibility Progress for the Second Implementation Period of the Regional Haze Program” (“2018 Visibility Tracking Guidance”), [^24] and the June 2020 “Recommendation for the Use of Patched and Substituted Data and Clarification of Data Completeness for Tracking Visibility Progress for the Second Implementation Period of the Regional Haze Program” and associated Technical Addendum (“2020 Data Completeness Memo”). [^25]

[^22] Guidance on Regional Haze State Implementation Plans for the Second Implementation Period. *https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period.* The EPA Office of Air Quality Planning and Standards, Research Triangle Park (August 20, 2019).

[^23] Clarifications Regarding Regional Haze State Implementation Plans for the Second Implementation Period. *https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf.* The EPA Office of Air Quality Planning and Standards, Research Triangle Park (July 8, 2021).

[^24] Technical Guidance on Tracking Visibility Progress for the Second Implementation Period of the Regional Haze Program. *https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional.* The EPA Office of Air Quality Planning and Standards, Research Triangle Park. (December 20, 2018).

[^25] Recommendation for the Use of Patched and Substituted Data and Clarification of Data Completeness for Tracking Visibility Progress for the Second Implementation Period of the Regional Haze Program. *https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program.* The EPA Office of Air Quality Planning and Standards, Research Triangle Park (June 3, 2020).

As previously explained in the 2021 Clarifications Memo, the EPA intends for the second implementation period of the regional haze program to secure meaningful reductions in visibility impairing pollutants that build on the significant progress states have achieved to date. The EPA also recognizes that analyses regarding reasonable progress are state-specific and that, based on states' and sources' individual circumstances, what constitutes reasonable reductions in visibility impairing pollutants will vary from state-to-state. While there exist many opportunities for states to leverage both ongoing and upcoming emission reductions under other Clean Air Act programs, the EPA expects states to undertake rigorous reasonable progress analyses that identify further opportunities to advance the national visibility goal consistent with the statutory and regulatory requirements. [^26] This is consistent with Congress's determination that a visibility protection program is needed in addition to the Clean Air Act's National Ambient Air Quality Standards and Prevention of Significant Deterioration programs, as further emission reductions may be necessary to adequately protect visibility in Class I areas throughout the country. [^27]

[^26] See generally 2021 Clarifications Memo.

[^27] See, *e.g.,* H.R. Rep No. 95-294 at 205 (“In determining how to best remedy the growing visibility problem in these areas of great scenic importance, the committee realizes that as a matter of equity, the national ambient air quality standards cannot be revised to adequately protect visibility in all areas of the country.”), (“the mandatory class I increments of [the PSD program] do not adequately protect visibility in class I areas”).

**B. Roles of Agencies in Addressing Regional Haze**

Because the air pollutants and pollution affecting visibility in Class I areas can be transported over long distances, successful implementation of the regional haze program requires long-term, regional coordination among multiple jurisdictions and agencies that have responsibility for Class I areas and the emissions that impact visibility in those areas. In order to address regional haze, states need to develop strategies in coordination with one another, considering the effect of emissions from one jurisdiction on the air quality in another. Five regional planning organizations, [^28] which include representation from state and tribal governments, the EPA, and Federal Land Managers, were developed in the lead-up to the first implementation period to address regional haze. Regional planning organizations evaluate technical information to better understand how emissions from State and Tribal lands impact Class I areas across the country, pursue the development of regional strategies to reduce emissions of particulate matter and other pollutants leading to regional haze, and help states meet the consultation requirements of the Regional Haze Rule.

[^28] Regional planning organizations are sometimes also referred to as “multi-jurisdictional organizations”. For the purposes of this document, the terms regional planning organizations and multi-jurisdictional organizations are synonymous.

**Western Regional Air Partnership**

The Western Regional Air Partnership (WRAP) [^29] is one of the five regional planning organizations and functions as a voluntary partnership of state, Tribal, Federal, and local air agencies whose purpose is to understand current and evolving regional air quality issues in the West. There are 15 member states in the WRAP, including Oregon, in addition to 28 tribes and 30 local air  agency members. [^30] WRAP Federal partners are the EPA, National Parks Service, Fish and Wildlife Service, Forest Service, and Bureau of Land Management. The WRAP membership formed a workgroup to develop a planning framework for state regional haze second planning period SIPs. Based on emissions and monitoring data supplied by its membership, the WRAP produced a technical system to support regional modeling of visibility impacts at Class I areas across the west. [^31] The WRAP Technical Support System consolidated air quality monitoring data, meteorological and receptor modeling data analyses, emissions inventories and projections, and gridded air quality/visibility regional modeling results. The WRAP Technical Support System is accessible by member states and allows for the creation of maps, figures, and tables to export and use in state plan development, and maintains the original source data for verification and further analysis.

[^29] The WRAP website may be found at *https://www.wrapair2.org.*

[^30] The WRAP membership list may be found at *https://www.wrapair2.org/membership.aspx.*

[^31] Technical information may be found at *https://www.wrapair2.org/RHPWG.aspx.*

**III. Requirements for Regional Haze Plans for the Second Implementation Period**

Under the Clean Air Act and the EPA's regulations, all 50 states, the District of Columbia, and the United States (U.S.) Virgin Islands are required to submit regional haze SIPs satisfying the applicable requirements for the second implementation period of the regional haze program by July 31, 2021. Each state's SIP must contain a long-term strategy for making reasonable progress toward meeting the national goal of remedying any existing and preventing any future anthropogenic visibility impairment in Class I areas. [^32] To this end, 40 CFR 51.308(f) lays out the process by which states determine what constitutes their long-term strategies, with the order of the requirements in § 51.308(f)(1) through (3) generally mirroring the order of the steps in the reasonable progress analysis [^33] and (f)(4) through (6) containing additional, related requirements. Broadly speaking, a state first must identify the Class I areas within the state and determine the Class I areas outside the state in which visibility may be affected by emissions from the state. These are the Class I areas that must be addressed in the state's long-term strategy. [^34] For each Class I area within its borders, a state must then calculate the baseline, current, and natural visibility conditions for that area, as well as the visibility improvement made to date and the uniform rate of progress. [^35] Each state having a Class I area and/or emissions that may affect visibility in a Class I area must then develop a long-term strategy that includes the enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress in such areas. A reasonable progress determination is based on applying the four factors in CAA section 169A(g)(1) to sources of visibility-impairing pollutants that the state has selected to assess for controls for the second implementation period. Additionally, as further explained below, the RHR at 40 CFR 51.308(f)(2)(iv) separately provides five “additional factors” [^36] that states must consider in developing their long-term strategies. See 40 CFR 51.308(f)(2). A state evaluates potential emission reduction measures for those selected sources and determines which are necessary to make reasonable progress. Those measures are then incorporated into the state's long-term strategy. After a state has developed its long-term strategy, it then establishes reasonable progress goals for each Class I area within its borders by modeling the visibility impacts of all reasonable progress controls at the end of the second implementation period, *i.e.,* in 2028, as well as the impacts of other requirements of the Clean Air Act. The reasonable progress goals include reasonable progress controls not only for sources in the state in which the Class I area is located, but also for sources in other states that contribute to visibility impairment in that area. The reasonable progress goals are then compared to the baseline visibility conditions and the uniform rate of progress to ensure that progress is being made towards the statutory goal of preventing any future and remedying any existing anthropogenic visibility impairment in Class I areas. [^37]

[^32] Clean Air Act section 169A(b)(2)(B).

[^33] The EPA explained in the 2017 Regional Haze Rule Revisions that we were adopting new regulatory language in 40 CFR 51.308(f) that, unlike the structure in 51.308(d), “tracked the actual planning sequence.” (82 FR 3091, January 10, 2017).

[^34] 40 CFR 51.308(f), (f)(2).

[^35] 40 CFR 51.308(f)(1).

[^36] The five “additional factors” for consideration in § 51.308(f)(2)(iv) are distinct from the four factors listed in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states must consider and apply to sources in determining reasonable progress.

[^37] 40 CFR 51.308(f)(2) and (3).

In addition to satisfying the requirements at 40 CFR 51.308(f) related to reasonable progress, the regional haze SIP revisions for the second implementation period must address the requirements in 40 CFR 51.308(g)(1) through (5) pertaining to periodic reports describing progress towards the reasonable progress goals, 40 CFR 51.308(f)(5), as well as requirements for Federal Land Manager consultation that apply to all visibility protection SIPs and SIP revisions. [^38]

[^38] 40 CFR 51.308(i).

A state must submit its regional haze SIP and subsequent SIP revisions to the EPA according to the requirements applicable to all SIP revisions under the Clean Air Act and the EPA's regulations. [^39] Upon EPA approval, a SIP is enforceable by the EPA and the public under the Clean Air Act. If the EPA finds that a state fails to make a required SIP revision, or if the EPA finds that a state's SIP is incomplete or if disapproves the SIP, the EPA must promulgate a Federal implementation plan (FIP) that satisfies the applicable requirements. [^40]

[^39] See Clean Air Act section 169(b)(2); Clean Air Act section 110(a).

[^40] Clean Air Act section 110(c)(1).

**A. Identification of Class I Areas**

The first step in developing a regional haze SIP is for a state to determine which Class I areas, in addition to those within its borders, “may be affected” by emissions from within the state. In the 1999 Regional Haze Rule, the EPA determined that all states contribute to visibility impairment in at least one Class I area and explained that the statute and regulations lay out an “extremely low triggering threshold” for determining “whether States should be required to engage in air quality planning and analysis as a prerequisite to determining the need for control of emissions from sources within their State.” [^41]

[^41] 64 FR 35714, 35720-35722, July 1, 1999.

A state must determine which Class I areas must be addressed by its SIP by evaluating the total emissions of visibility impairing pollutants from all sources within the state. While the Regional Haze Rule does not require this evaluation to be conducted in any particular manner, the EPA's 2019 Guidance provides recommendations for how such an assessment might be accomplished, including by, where appropriate, using the determinations previously made for the first implementation period. 2019 Guidance at 8-9. In addition, the determination of which Class I areas may be affected by a state's emissions is subject to the requirement in 40 CFR 51.308(f)(2)(iii) 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 Federal area it affects.”

**B. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress**

As part of assessing whether a SIP submission for the second implementation period is providing for reasonable progress towards the national visibility goal, the Regional Haze Rule contains requirements in 40 CFR 51.308(f)(1) related to tracking visibility improvement over time. The requirements of this section apply only to states having Class I areas within their borders; the required calculations must be made for each such Class I area. The EPA's 2018 Visibility Tracking Guidance [^42] provides recommendations to assist states in satisfying their obligations under 40 CFR 51.308(f)(1); specifically, in developing information on baseline, current, and natural visibility conditions, and in making optional adjustments to the uniform rate of progress to account for the impacts of international anthropogenic emissions and prescribed fires. [^43]

[^42] The 2018 Visibility Tracking Guidance references and relies on parts of the 2003 Tracking Guidance: “Guidance for Tracking Progress Under the Regional Haze Rule,” which can be found at *https://www.epa.gov/sites/default/files/2021-03/documents/tracking.pdf.*

[^43] 82 FR 3078, 3103-05, January 10, 2017.

The Regional Haze Rule requires tracking of visibility conditions on two sets of days: the clearest and the most impaired days. Visibility conditions for both sets of days are expressed as the average deciview index for the relevant five-year period (the period representing baseline or current visibility conditions). The Regional Haze Rule provides that the relevant sets of days for visibility tracking purposes are the 20% clearest (the 20% of monitored days in a calendar year with the lowest values of the deciview index) and 20% most impaired days (the 20% of monitored days in a calendar year with the highest amounts of anthropogenic visibility impairment). [^44] A state must calculate visibility conditions for both the 20% clearest and 20% most impaired days for the baseline period of 2000-2004 and the most recent five-year period for which visibility monitoring data are available (representing current visibility conditions). [^45] States must also calculate natural visibility conditions for the clearest and most impaired days, [^46] by estimating the conditions that would exist on those two sets of days absent anthropogenic visibility impairment. [^47] Using all these data, states must then calculate, for each Class I area, the amount of progress made since the baseline period (2000-2004) and how much improvement is left to achieve in order to reach natural visibility conditions.

[^44] 40 CFR 51.301. This document also refers to the 20% clearest and 20% most anthropogenically impaired days as the “clearest” and “most impaired” or “most anthropogenically impaired” days, respectively.

[^45] 40 CFR 51.308(f)(1)(i), (iii).

[^46] The Regional Haze Rule at 40 CFR 51.308(f)(1)(ii) contains an error related to the requirement for calculating two sets of natural conditions values. The rule says “most impaired days or the clearest days” where it should say “most impaired days and clearest days.” This is an error that was intended to be corrected in the 2017 Regional Haze Rule Revisions but did not get corrected in the final rule language. This is supported by the preamble text at 82 FR 3098, January 0, 2017: “In the final version of 40 CFR 51.308(f)(1)(ii), an occurrence of “or” has been corrected to “and” to indicate that natural visibility conditions for both the most impaired days and the clearest days must be based on available monitoring information.”

[^47] 40 CFR 51.308(f)(1)(ii).

Using the data for the set of most impaired days only, states must plot a line between visibility conditions in the baseline period and natural visibility conditions for each Class I area to determine the uniform rate of progress—the amount of visibility improvement, measured in deciviews, that would need to be achieved during each implementation period in order to achieve natural visibility conditions by the end of 2064. The uniform rate of progress is used in later steps of the reasonable progress analysis for informational purposes and to provide a non-enforceable benchmark against which to assess a Class I area's rate of visibility improvement. [^48] Additionally, in the 2017 Regional Haze Rule Revisions, the EPA provided states the option of proposing to adjust the endpoint of the uniform rate of progress to account for impacts of anthropogenic sources outside the U.S. and/or impacts of certain types of wildland prescribed fires. These adjustments, which must be approved by the EPA, are intended to avoid any perception that states should compensate for impacts from international anthropogenic sources and to give states the flexibility to determine that limiting the use of wildland-prescribed fire is not necessary for reasonable progress. [^49]

[^48] Being on or below the uniform rate of progress is not a “safe harbor”; *i.e.,* achieving the uniform rate of progress does not mean that a Class I area is making “reasonable progress” and does not relieve a state from using the four statutory factors to determine what level of control is needed to achieve such progress. See, *e.g.,* 82 FR 3078, 3093, January 10, 2017.

[^49] 82 FR 3078, 3107, January 10, 2017, footnote 116.

The EPA's 2018 Visibility Tracking Guidance can be used to help satisfy the 40 CFR 51.308(f)(1) requirements, including in developing information on baseline, current, and natural visibility conditions, and in making optional adjustments to the uniform rate of progress. In addition, the 2020 Data Completeness Memo provides recommendations on the data completeness language referenced in 40 CFR 51.308(f)(1)(i) and provides updated natural conditions estimates for each Class I area.

**C. Long-Term Strategy for Regional Haze**

The core component of a regional haze SIP submission is a long-term strategy that addresses regional haze in each Class I area within a state's borders and each Class I area that may be affected by emissions from the state. The long-term strategy “must include the enforceable emissions limitations, compliance schedules, and other measures that are necessary to make reasonable progress, as determined pursuant to (f)(2)(i) through (iv).” [^50] The amount of progress that is “reasonable progress” is based on applying the four statutory factors in Clean Air Act section 169A(g)(1) in an evaluation of potential control options for sources of visibility impairing pollutants, which is referred to as a “four-factor” analysis. The outcome of that analysis is the emission reduction measures that a particular source or group of sources needs to implement in order to make reasonable progress towards the national visibility goal. [^51] Emission reduction measures that are necessary to make reasonable progress may be either new, additional control measures for a source, or they may be the existing emission reduction measures that a source is already implementing. [^52] Such measures must be represented by “enforceable emissions limitations, compliance schedules, and other measures” ( *i.e.,* any additional compliance tools) in a state's long-term strategy in its SIP. [^53]

[^50] 40 CFR 51.308(f)(2).

[^51] 40 CFR 51.308(f)(2)(i).

[^52] See 2019 Guidance at 43; 2021 Clarifications Memo at 8-10.

[^53] 40 CFR 51.308(f)(2).

Section 51.308(f)(2)(i) provides the requirements for the four-factor analysis. The first step of this analysis entails selecting the sources to be evaluated for emission reduction measures; to this end, states should  consider “major and minor stationary sources or groups of sources, mobile sources, and area sources” of visibility impairing pollutants for potential four-factor control analysis. [^54] A threshold question at this step is which visibility impairing pollutants will be analyzed. As the EPA previously explained, consistent with the first implementation period, the EPA generally expects that each state will analyze at least SO <sub>2</sub> and NO <sub>X</sub> in selecting sources and determining control measures. [^55] A state that chooses not to consider at least these two pollutants should demonstrate why such consideration would be unreasonable. [^56]

[^54] 40 CFR 51.308(f)(2)(i).

[^55] See 2019 Guidance at 12, 2021 Clarifications Memo at 4.

[^56] 2021 Clarifications Memo at 4.

While states have the option to analyze all sources, the 2019 Guidance explains that “an analysis of control measures is not required for every source in each implementation period,” and that “[s]electing a set of sources for analysis of control measures in each implementation period is . . . consistent with the Regional Haze Rule, which sets up an iterative planning process and anticipates that a state may not need to analyze control measures for all its sources in a given SIP revision.” [^57] However, given that source selection is the basis of all subsequent control determinations, a reasonable source selection process “should be designed and conducted to ensure that source selection results in a set of pollutants and sources the evaluation of which has the potential to meaningfully reduce their contributions to visibility impairment.” [^58]

[^57] 2019 Guidance at 9.

[^58] 2021 Clarifications Memo at 3.

The EPA explained in the 2021 Clarifications Memo that each state has an obligation to submit a long-term strategy that addresses the regional haze visibility impairment that results from emissions from within that state. Thus, source selection should focus on the in-state contribution to visibility impairment and be designed to capture a meaningful portion of the state's total contribution to visibility impairment in Class I areas. A state should not decline to select its largest in-state sources on the basis that there are even larger out-of-state contributors. [^59]

[^59]*Id.* at 4. Similarly, in responding to comments on the 2017 Regional Haze Rule Revisions EPA explained that “[a] state should not fail to address its many relatively low-impact sources merely because it only has such sources and another state has even more low-impact sources and/or some high impact sources.” Responses to Comments on Protection of Visibility: Amendments to Requirements for State Plans; Proposed Rule. 81 FR 26942, 26987-26988, May 4, 2016.

Thus, while states have discretion to choose any source selection methodology that is reasonable, whatever choices they make should be reasonably explained. To this end, 40 CFR 51.308(f)(2)(i) requires that a state's SIP submission include “a description of the criteria it used to determine which sources or groups of sources it evaluated.” The technical basis for source selection, which may include methods for quantifying potential visibility impacts such as emissions divided by distance metrics, trajectory analyses, residence time analyses, and/or photochemical modeling, must also be appropriately documented, as required by 40 CFR 51.308(f)(2)(iii).

Once a state has selected the set of sources, the next step is to determine the emissions reduction measures for those sources that are necessary to make reasonable progress for the second implementation period. [^60] This is accomplished by considering the 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.” [^61] The EPA has explained that the four-factor analysis is an assessment of potential emission reduction measures ( *i.e.,* control options) for sources; “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 [Clean Air Act's] reasonable progress mandate.” [^62] Thus, for each source it has selected for four-factor analysis, [^63] a state must consider a “meaningful set” of technically feasible control options for reducing emissions of visibility impairing pollutants. [^64] The 2019 Guidance provides that “[a] state must reasonably pick and justify the measures that it will consider, recognizing that there is no statutory or regulatory requirement to consider all technically feasible measures or any particular measures. A range of technically feasible measures available to reduce emissions would be one way to justify a reasonable set.” [^65]

[^60] The Clean Air Act provides that, “[i]n determining reasonable progress there shall be taken into consideration” the four statutory factors. Clean Air Act section 169A(g)(1). However, in addition to four-factor analyses for selected sources, groups of sources, or source categories, a state may also consider additional emission reduction measures for inclusion in its long-term strategy, *e.g.,* from other newly adopted, on-the-books, or on-the-way rules and measures for sources not selected for four-factor analysis for the second planning period.

[^61] Clean Air Act section 169A(g)(1).

[^62] 82 FR 3078, 3091, January 10, 2017.

[^63] “Each source” or “particular source” is used here as shorthand. While a source-specific analysis is one way of applying the four factors, neither the statute nor the Regional Haze Rule requires states to evaluate individual sources. Rather, states have “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.” 82 FR 3078, 3088, January 10, 2017. However, not all approaches to grouping sources for four-factor analysis are necessarily reasonable; the reasonableness of grouping sources in any particular instance will depend on the circumstances and the manner in which grouping is conducted. If it is feasible to establish and enforce different requirements for sources or subgroups of sources, and if relevant factors can be quantified for those sources or subgroups, then states should make a separate reasonable progress determination for each source or subgroup. 2021 Clarifications Memo at 7-8.

[^64] 82 FR 3078, 3088, January 10, 2017.

[^65] 2019 Guidance at 29.

The EPA's 2021 Clarifications Memo provides further guidance on what constitutes a reasonable set of control options for consideration: “A reasonable four-factor analysis will consider the full range of potentially reasonable options for reducing emissions.” [^66] In addition to add-on controls and other retrofits ( *i.e.,* new emission reduction measures for sources), the EPA explained that states should generally analyze efficiency improvements for sources' existing measures as control options in their four-factor analyses, as in many cases such improvements are reasonable given that they typically involve only additional operation and maintenance costs. Additionally, the 2021 Clarifications Memo provides that states that have assumed a higher emission rate than a source has achieved or could potentially achieve using its existing measures should also consider lower emission rates as potential control options. That is, a state should consider a source's recent actual and projected emission rates to determine if it could reasonably attain lower emission rates with its existing measures. If so, the state should analyze the lower emission rate as a control option for reducing emissions. [^67] The EPA's recommendations to analyze potential efficiency improvements and achievable lower emission rates apply to both sources that have been selected for four-factor analysis and those that have forgone a four-factor analysis on the basis of existing “effective controls.” [^68]

[^66] 2021 Clarifications Memo at 7.

[^67] Ibid.

[^68] See 2021 Clarifications Memo at 5, 10.

After identifying a reasonable set of potential control options for the sources it has selected, a state then collects  information on the four factors with regard to each option identified. The EPA has also explained that, in addition to the four statutory factors, states have flexibility under the Clean Air Act and Regional Haze Rule to reasonably consider visibility benefits as an additional factor alongside the four statutory factors. [^69] The 2019 Guidance provides recommendations for the types of information that can be used to characterize the four factors (with or without visibility), as well as ways in which states might reasonably consider and balance that information to determine which of the potential control options is necessary to make reasonable progress. [^70] The 2021 Clarifications Memo contains further guidance on how states can reasonably consider modeled visibility impacts or benefits in the context of a four-factor analysis. [^71] Specifically, the EPA explained that while visibility can reasonably be used when comparing and choosing between multiple reasonable control options, it should not be used to summarily reject controls that are reasonable given the four statutory factors. [^72] Ultimately, while states have discretion to reasonably weigh the factors and to determine what level of control is needed, § 51.308(f)(2)(i) provides that a state “must include in its implementation plan a description of . . . how the four factors were taken into consideration in selecting the measure for inclusion in its long-term strategy.”

[^69] See, *e.g.,* Responses to Comments on Protection of Visibility: Amendments to Requirements for State Plans; Proposed Rule (81 FR 26942, May 4, 2016), Docket Number EPA-HQ-OAR-2015-0531, U.S. Environmental Protection Agency at 186; 2019 Guidance at 36-37.

[^70] See 2019 Guidance at 30-36.

[^71] 2021 Clarifications Memo at 12-13, 14-15.

[^72] 2021 Clarifications Memo at 13.

As explained above, 40 CFR 51.308(f)(2)(i) requires states to determine the emission reduction measures for sources that are necessary to make reasonable progress by considering the four factors. Pursuant to 40 CFR 51.308(f)(2), measures that are necessary to make reasonable progress towards the national visibility goal must be included in a state's long-term strategy and in its SIP. [^73] If the outcome of a four-factor analysis is a new, additional emission reduction measure for a source, that new measure is necessary to make reasonable progress towards remedying existing anthropogenic visibility impairment and must be included in the SIP. If the outcome of a four-factor analysis is that no new measures are reasonable for a source, continued implementation of the source's existing measures is generally necessary to prevent future emission increases and thus to make reasonable progress towards the second part of the national visibility goal: preventing future anthropogenic visibility impairment. [^74] That is, when the result of a four-factor analysis is that no new measures are necessary to make reasonable progress, the source's existing measures are generally necessary to make reasonable progress and must be included in the SIP. However, there may be circumstances in which a state can demonstrate that a source's existing measures are *not* necessary to make reasonable progress. Specifically, if a state can demonstrate that a source will continue to implement its existing measures and will not increase its emission rate, it may not be necessary to have those measures in the long-term strategy in order to prevent future emission increases and future visibility impairment. The EPA's 2021 Clarifications Memo provides further explanation and guidance on how states may demonstrate that a source's existing measures are not necessary to make reasonable progress. [^75] If the state can make such a demonstration, it need not include a source's existing measures in the long-term strategy or its SIP.

[^73] States may choose to, but are not required to, include measures in their long-term strategies beyond just the emission reduction measures that are necessary for reasonable progress. See 2021 Clarifications Memo at 16. For example, states with smoke management programs may choose to submit their smoke management plans to the EPA for inclusion in their SIPs but are not required to do so. See, *e.g.,* 82 FR 3078, 3108-3109, January 10, 2017 (requirement to consider smoke management practices and smoke management programs under 40 CFR 51.308(f)(2)(iv) does not require states to adopt such practices or programs into their SIPs, although they may elect to do so).

[^74] See Clean Air Act section 169A(a)(1). See also 2021 Clarifications Memo at 8.

[^75] See 2021 Clarifications Memo at 8-10.

As with source selection, the characterization of information on each of the factors is also subject to the documentation requirement in 40 CFR 51.308(f)(2)(iii). The reasonable progress analysis, including source selection, information gathering, characterization of the four statutory factors (and potentially visibility), balancing of the four factors, and selection of the emission reduction measures that represent reasonable progress, is a technically complex exercise, but also a flexible one that provides states with bounded discretion to design and implement approaches appropriate to their circumstances. Given this flexibility, 40 CFR 51.308(f)(2)(iii) plays an important function in requiring a state to document the technical basis for its decision making so that the public and the EPA can comprehend and evaluate the information and analysis the state relied upon to determine what emission reduction measures must be in place to make reasonable progress. The technical documentation must include the modeling, monitoring, cost, engineering, and emissions information on which the state relied to determine the measures necessary to make reasonable progress. This documentation requirement can be met through the provision of and reliance on technical analyses developed through a regional planning process, so long as that process and its output has been approved by all state participants. In addition to the explicit regulatory requirement to document the technical basis of their reasonable progress determinations, states are also subject to the general principle that those determinations must be reasonably moored to the statute. [^76] That is, a state's decisions about the emission reduction measures that are necessary to make reasonable progress must be consistent with the statutory goal of remedying existing and preventing future visibility impairment.

[^76] See *Arizona ex rel. Darwin* v. *U.S. EPA* , 815 F.3d 519, 531 (9th Cir. 2016); *Nebraska* v. *U.S. EPA* , 812 F.3d 662, 668 (8th Cir. 2016); *North Dakota* v. *EPA* , 730 F.3d 750, 761 (8th Cir. 2013); *Oklahoma* v. *EPA* , 723 F.3d 1201, 1206, 1208-10 (10th Cir. 2013); cf. also *National Parks Conservation Association* v. *EPA* , 803 F.3d 151, 165 (3d Cir. 2015); *Alaska Department of Environmental Conservation* v. *EPA* , 540 U.S. 461, 485, 490 (2004).

The four statutory factors (and potentially visibility) are used to determine what emission reduction measures for selected sources must be included in a state's long-term strategy for making reasonable progress. Additionally, the Regional Haze Rule at 40 CFR 51.308(f)(2)(iv) separately provides five “additional factors” [^77] that states must consider in developing their long-term strategies: (1) emission reductions due to ongoing air pollution control programs, including measures to address reasonably attributable visibility impairment; (2) measures to reduce the impacts of construction activities; (3) source retirement and replacement schedules; (4) basic smoke management practices for prescribed fire used for agricultural and wildland vegetation management purposes and smoke management programs; and (5) 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. The 2019 Guidance provides that a state may satisfy this requirement by considering these additional factors in the process of selecting sources for four-factor analysis, when performing that analysis, or both, and that not every one of the additional factors needs to be considered at the same stage of the process. [^78] The EPA provided further guidance on the five additional factors in the 2021 Clarifications Memo, explaining that a state should generally not reject cost-effective and otherwise reasonable controls merely because there have been emission reductions since the first planning period owing to other ongoing air pollution control programs or merely because visibility is otherwise projected to improve at Class I areas. Additionally, states generally should not rely on these additional factors to summarily assert that the state has already made sufficient progress and, therefore, no sources need to be selected or no new controls are needed regardless of the outcome of four-factor analyses. [^79]

[^77] The five “additional factors” for consideration in 40 CFR 51.308(f)(2)(iv) are distinct from the four factors listed in Clean Air Act section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states must consider and apply to sources in determining reasonable progress.

[^78] See 2019 Guidance at 21.

[^79] 2021 Clarifications Memo at 13. In particular, the EPA explained in the 2021 Clarifications Memo that states should not rely on the considerations in 40 CFR 51.308(f)(2)(iv)(A) and (E) to summarily assert that the state has already made sufficient progress and therefore does not need to achieve any additional emission reductions. 2021 Clarifications Memo at 13.

Because the air pollution that causes regional haze crosses state boundaries, 40 CFR 51.308(f)(2)(ii) requires a state to consult with other states that also have emissions that are reasonably anticipated to contribute to visibility impairment in a given Class I area. Consultation allows for each state that impacts visibility in an area to share whatever technical information, analyses, and control determinations may be necessary to develop coordinated emission management strategies. This coordination may be managed through inter- and intra-regional planning organization consultation and the development of regional emissions strategies; additional consultations between states outside of regional planning organization processes may also occur. If a state, pursuant to consultation, agrees that certain measures ( *e.g.,* a certain emission limitation) are necessary to make reasonable progress at a Class I area, it must include those measures in its SIP. [^80] Additionally, the Regional Haze Rule requires that states that contribute to visibility impairment at the same Class I area consider the emission reduction measures the other contributing states have identified as being necessary to make reasonable progress for their own sources. [^81] If a state has been asked to consider or adopt certain emission reduction measures, but ultimately determines those measures are not necessary to make reasonable progress, that state must document in its SIP the actions taken to resolve the disagreement. [^82] The EPA will consider the technical information and explanations presented by the submitting state and the state with which it disagrees when considering whether to approve the state's SIP. [^83] Under all circumstances, a state must document in its SIP submission all substantive consultations with other contributing states. [^84]

[^80] 40 CFR 51.308(f)(2)(ii)(A).

[^81] 40 CFR 51.308(f)(2)(ii)(B).

[^82] 40 CFR 51.308(f)(2)(ii)(C).

[^83] See id.; 2019 Guidance at 53.

[^84] 40 CFR 51.308(f)(2)(ii)(C).

**D. Reasonable Progress Goals**

Reasonable progress goals “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.” [^85] Their primary purpose is to assist the public and the EPA in assessing the reasonableness of states' long-term strategies for making reasonable progress towards the national visibility goal. [^86] States in which Class I areas are located must establish two reasonable progress goals, both in deciviews—one representing visibility conditions on the clearest days and one representing visibility on the most anthropogenically impaired days—for each area within their borders. [^87] The two reasonable progress goals are intended to reflect the projected impacts, on the two sets of days, of the emission reduction measures the state with the Class I area, as well as all other contributing states, have included in their long-term strategies for the second implementation period. [^88] The reasonable progress goals also account for the projected impacts of implementing other Clean Air Act requirements, including non-SIP based requirements. Because reasonable progress goals are the modeled result of the measures in states' long-term strategies (as well as other measures required under the Clean Air Act), they cannot be determined before states have conducted their four-factor analyses and determined the control measures that are necessary to make reasonable progress. [^89]

[^85] 82 FR 3078, 3091, January 10, 2017.

[^86] See 40 CFR 51.308(f)(3)(iii) and (iv).

[^87] 40 CFR 51.308(f)(3)(i).

[^88] Reasonable progress goals are intended to reflect the projected impacts of the measures all contributing states include in their long-term strategies. However, due to the timing of analyses and of control determinations by other states, other on-going emissions changes, a particular state's reasonable progress goals may not reflect all control measures and emissions reductions that are expected to occur by the end of the implementation period. The 2019 Guidance provides recommendations for addressing the timing of reasonable progress goal calculations when states are developing their long-term strategies on disparate schedules, as well as for adjusting reasonable progress goals using a post-modeling approach. 2019 Guidance at 47-48.

[^89] 2021 Clarifications Memo at 6.

For the second implementation period, the reasonable progress goals are set for 2028. Reasonable progress goals are not enforceable targets, 40 CFR 51.308(f)(3)(iii); rather, they “provide a way for the states to check the projected outcome of the [long-term strategy] against the goals for visibility improvement.” [^90] While states are not legally obligated to achieve the visibility conditions described in their reasonable progress goals, 40 CFR 51.308(f)(3)(i) requires that “[t]he long-term strategy and the reasonable progress goals must provide for an improvement in visibility for the most impaired days since the baseline period and ensure no degradation in visibility for the clearest days since the baseline period.” Thus, states are required to have emission reduction measures in their long-term strategies that are projected to achieve visibility conditions on the most impaired days that are better than the baseline period and shows no degradation on the clearest days compared to the clearest days from the baseline period. The baseline period for the purpose of this comparison is the baseline visibility condition—the annual average visibility condition for the period 2000-2004. [^91]

[^90] 2019 Guidance at 46.

[^91] 40 CFR 51.308(f)(1)(i), 82 FR 2078, 3097-98, January 10, 2017.

So that reasonable progress goals may also serve as a metric for assessing the amount of progress a state is making towards the national visibility goal, the Regional Haze Rule requires states with Class I areas to compare the 2028 reasonable progress goal for the most impaired days to the corresponding point on the uniform rate of progress line (representing visibility conditions in 2028 if visibility were to improve at a linear rate from conditions in the baseline period of 2000-2004 to natural visibility conditions in 2064). If the most impaired days reasonable progress goal in 2028 is above the uniform rate of progress ( *i.e.,* if visibility conditions are improving more slowly than the rate  described by the uniform rate of progress), each state that contributes to visibility impairment in the Class I area must demonstrate, based on the four-factor analysis required under 40 CFR 51.308(f)(2)(i), that no additional emission reduction measures would be reasonable to include in its long-term strategy. [^92] To this end, 40 CFR 51.308(f)(3)(ii) requires that each state contributing to visibility impairment in a Class I area that is projected to improve more slowly than the uniform rate of progress provide “a robust demonstration, including documenting the criteria used to determine which sources or groups [of] sources were evaluated and how the four factors required by paragraph (f)(2)(i) were taken into consideration in selecting the measures for inclusion in its long-term strategy.” The 2019 Guidance provides suggestions about how such a “robust demonstration” might be conducted. [^93]

[^92] 40 CFR 51.308(f)(3)(ii).

[^93] 2019 Guidance at 50-51.

The 2017 Regional Haze Rule, 2019 Guidance, and 2021 Clarifications Memo also explain that projecting a reasonable progress goal that is on or below the uniform rate of progress based on only on-the-books and/or on-the-way control measures ( *i.e.,* control measures already required or anticipated before the four-factor analysis is conducted) is not a “safe harbor” from the Clean Air Act's and Regional Haze Rule's requirement that all states must conduct a four-factor analysis to determine what emission reduction measures constitute reasonable progress. The uniform rate of progress is a planning metric used to gauge the amount of progress made thus far and the amount left before reaching natural visibility conditions. However, the uniform rate of progress is not based on consideration of the four statutory factors and therefore cannot answer the question of whether the amount of progress being made in any particular implementation period is “reasonable progress.” [^94]

[^94] 82 FR 3078, 3093, 3099-3100, January 10, 2017; 2019 Guidance at 22; 2021 Clarifications Memo at 15-16.

**E. Monitoring Strategy and Other State Implementation Plan Requirements**

Section 51.308(f)(6) requires states to have certain strategies and elements in place for assessing and reporting on visibility. Individual requirements under this section apply either to states with Class I areas within their borders, states with no Class I areas but that are reasonably anticipated to cause or contribute to visibility impairment in any Class I area, or both. A state with Class I areas within its borders must submit with its SIP revision a monitoring strategy for measuring, characterizing, and reporting regional haze visibility impairment that is representative of all Class I areas within the state. SIP revisions for such states must also provide for the establishment of any additional monitoring sites or equipment needed to assess visibility conditions in Class I areas, as well as reporting of all visibility monitoring data to the EPA at least annually. Compliance with the monitoring strategy requirement may be met through a state's participation in the Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network, which is used to measure visibility impairment caused by air pollution at the 156 Class I areas covered by the visibility program. [^95] The IMPROVE monitoring data is used to determine the 20% most anthropogenically impaired and 20% clearest sets of days every year at each Class I area and tracks visibility impairment over time.

[^95] 40 CFR 51.308(f)(6), (f)(6)(i), (f)(6)(iv).

All states' SIPs must provide for procedures by which monitoring data and other information are used to determine the contribution of emissions from within the state to regional haze visibility impairment in affected Class I areas. [^96] Section 51.308(f)(6)(v) further requires that all states' SIPs provide for a statewide inventory of emissions of pollutants that are reasonably anticipated to cause or contribute to visibility impairment in any Class I area; the inventory must include emissions for the most recent year for which data are available and estimates of future projected emissions. States must also include commitments to update their inventories periodically. The inventories themselves do not need to be included as elements in the SIP and are not subject to EPA review as part of the EPA's evaluation of a SIP revision. [^97] All states' SIPs must also provide for any other elements, including reporting, recordkeeping, and other measures, that are necessary for states to assess and report on visibility. [^98] Per the 2019 Guidance, a state may note in its regional haze SIP that its compliance with the Air Emissions Reporting Rule in 40 CFR part 51, subpart A satisfies the requirement to provide for an emissions inventory for the most recent year for which data are available. To satisfy the requirement to provide estimates of future projected emissions, a state may explain in its SIP how projected emissions were developed for use in establishing reasonable progress goals for its own and nearby Class I areas. [^99]

[^96] 40 CFR 51.308(f)(6)(ii), (iii).

[^97] See “Step 8: Additional requirements for regional haze SIPs” in 2019 Regional Haze Guidance at 55.

[^98] 40 CFR 51.308(f)(6)(vi).

[^99] See “Step 8: Additional requirements for regional haze SIPs” in 2019 Regional Haze Guidance at 55.

Separate from the requirements related to monitoring for regional haze purposes under 40 CFR 51.308(f)(6), the Regional Haze Rule also contains a requirement at 40 CFR 51.308(f)(4) related to any additional monitoring that may be needed to address visibility impairment in Class I areas from a single source or a small group of sources. This is called “reasonably attributable visibility impairment.” [^100] Under this provision, if the EPA or the Federal Land Manager of an affected Class I area has advised a state that additional monitoring is needed to assess reasonably attributable visibility impairment, the state must include in its SIP revision for the second implementation period an appropriate strategy for evaluating such impairment.

[^100] The EPA's visibility protection regulations define “reasonably attributable visibility impairment” as “visibility impairment that is caused by the emission of air pollutants from one, or a small number of sources.” 40 CFR 51.301.

**F. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals**

Section 51.308(f)(5) requires a state's regional haze SIP revision to address the requirements of paragraphs 40 CFR 51.308(g)(1) through (5) so that the plan revision due in 2021 will serve also as a progress report addressing the period since submission of the progress report for the first implementation period. The regional haze progress report requirement is designed to inform the public and the EPA about a state's implementation of its existing long-term strategy and whether such implementation is in fact resulting in the expected visibility improvement. [^101] To this end, every state's SIP revision for the second implementation period is required to describe the status of implementation of all measures included in the state's long-term strategy, including BART and reasonable progress emission reduction measures from the first implementation period, and the resulting emissions reductions. [^102]

[^101] 81 FR 26942, 26950, May 4, 2016; 82 FR 3078, 3119, January 10, 2017.

[^102] 40 CFR 51.308(g)(1) and (2).

A core component of the progress report requirements is an assessment of changes in visibility conditions on the  clearest and most impaired days. For second implementation period progress reports, 40 CFR 51.308(g)(3) requires states with Class I areas within their borders to first determine current visibility conditions for each area on the most impaired and clearest days, 40 CFR 51.308(g)(3)(i)(B), and then to calculate the difference between those current conditions and baseline (2000-2004) visibility conditions in order to assess progress made to date. [^103] States must also assess the changes in visibility impairment for the most impaired and clearest days since they submitted their first implementation period progress reports. [^104] Since different states submitted their first implementation period progress reports at different times, the starting point for this assessment will vary state by state.

[^103] 40 CFR 51.308(g)(3)(ii)(B).

[^104] 40 CFR 51.308(g)(3)(iii)(B), (f)(5).

Similarly, states must provide analyses tracking the change in emissions of pollutants contributing to visibility impairment from all sources and activities within the state over the period since they submitted their first implementation period progress reports. [^105] Changes in emissions should be identified by the type of source or activity. Section 51.308(g)(5) also addresses changes in emissions since the period addressed by the previous progress report and requires states' SIP revisions to include an assessment of any significant changes in anthropogenic emissions within or outside the state. This assessment must include an explanation of whether these changes in emissions were anticipated and whether they have limited or impeded progress in reducing emissions and improving visibility relative to what the state projected based on its long-term strategy for the first implementation period.

[^105] See 40 CFR 51.308(g)(4), (f)(5).

**G. Requirements for State and Federal Land Manager Coordination**

Clean Air Act section 169A(d) requires that before a state holds a public hearing on a proposed regional haze SIP revision, it must consult with the appropriate Federal Land Manager or Federal Land Managers; pursuant to that consultation, the state must include a summary of the Federal Land Managers' conclusions and recommendations in the notice to the public. Consistent with this statutory requirement, the Regional Haze Rule also requires that states “provide the [Federal Land Manager] with an opportunity for consultation, in person and at a point early enough in the State's policy analyses of its long-term strategy emission reduction obligation so that information and recommendations provided by the [Federal Land Manager] can meaningfully inform the State's decisions on the long-term strategy.” [^106] Consultation that occurs 120 days prior to any public hearing or public comment opportunity will be deemed “early enough,” but the Regional Haze Rule provides that in any event the opportunity for consultation must be provided at least 60 days before a public hearing or comment opportunity. This consultation must include the opportunity for the Federal Land Managers to discuss their assessment of visibility impairment in any Class I area and their recommendations on the development and implementation of strategies to address such impairment. [^107] In order for the EPA to evaluate whether Federal Land Manager consultation meeting the requirements of the Regional Haze Rule has occurred, the SIP submission should include documentation of the timing and content of such consultation. The SIP revision submitted to the EPA must also describe how the state addressed any comments provided by the Federal Land Managers. [^108] Finally, a SIP revision must provide procedures for continuing consultation between the state and Federal Land Managers regarding the state's visibility protection program, including development and review of SIP revisions, five-year progress reports, and the implementation of other programs having the potential to contribute to impairment of visibility in Class I areas. [^109]

[^106] 40 CFR 51.308(i)(2).

[^107] Ibid.

[^108] 40 CFR 51.308(i)(3).

[^109] 40 CFR 51.308(i)(4).

**IV. The EPA's Evaluation of the Oregon Regional Haze Submission for the Second Implementation Period**

**A. Background on the Oregon First Implementation Period SIP Submission**

Oregon submitted its regional haze SIP for the first implementation period (2008 through 2018) on December 9, 2010, as supplemented on February 01, 2011. The Clean Air Act required that the initial round of regional haze plans include, among other things, a long-term strategy for making reasonable progress and best available retrofit technology requirements for certain older stationary sources, where applicable. [^110] The EPA approved Oregon's first implementation period SIP submission in two actions published July 5, 2011 (76 FR 38997) and August 22, 2012 (77 FR 50611). Subsequently, on July 18, 2017, Oregon submitted a five-year progress report and the EPA approved the progress report on May 17, 2018 (83 FR 22853). [^111] In our action, we concluded that Oregon made adequate progress in improving visibility as a result of actions identified in the regional haze SIP. Specifically, based on 2010 through 2014 data, Oregon Class I areas attained the 2018 reasonable progress goals for improved visibility, except for one IMPROVE monitor highly impacted by wildfire. [^112]

[^110] The requirements for regional haze SIPs for the first implementation period are contained in Clean Air Act section 169A(b)(2)(B) and 40 CFR 51.308(d) and (e). See also 40 CFR 51.308(b).

[^111] For details, please see the progress report in the docket for the EPA's approval action on May 17, 2018 (83 FR 22853) at *https://www.regulations.gov* under docket number EPA-R10-OAR-2017-0482.

[^112] See Section III.B. *Summary of Visibility Conditions* of the proposed rule. 83 FR 11927, 11930, March 19, 2018.

**B. The Oregon Second Implementation Period SIP Submission and the EPA's Evaluation**

On April 29, 2022, and November 22, 2023, Oregon submitted revisions to the SIP to address its regional haze obligations for the second implementation period (2018 through 2028). [^113] The submissions may be found in the docket for this action. Oregon made its April 29, 2022 submission available for public comment on August 27, 2021 through November 1, 2021 [^114] and held a public hearing on October 27, 2021. [^115] The state received and responded to public comments and included the comments and comment responses in the SIP submission. [^116] Oregon made its November 22, 2023 submission available for public comment September 15, 2023 through October 21, 2023 and held a public hearing on October 16, 2023. [^117] The State received and responded to public comments and included the comments and comment responses in the SIP submission. [^118]

[^113] Clean Air Act sections 169A and 40 CFR 51.308(f).

[^114] Notice of Proposed Rulemaking, August 27, 2021, included in the docket for this action.

[^115] Staff report for the Oregon Environmental Quality Commission Meeting February. 3-4, 2022, included in the docket for this action.

[^116] Staff report for the Oregon Environmental Quality Commission Meeting February. 3-4, 2022, Summary of Public Comments and DEQ Responses.

[^117] Staff report for the Oregon Environmental Quality Commission Meeting November 17, 2023, at page 15-16.

[^118] Staff report for the Oregon Environmental Quality Commission Meeting November 17, 2023, at page 16.

The following sections of this preamble describe the Oregon SIP submission, including air quality  modeling conducted, source selection, four-factor analyses to determine what emission reduction measures constitute reasonable progress for the long-term strategy, assessment of progress made since the first implementation period in reducing emissions of visibility impairing pollutants, and the visibility improvement progress at Class I areas in Oregon and other states impacted by Oregon sources. This preamble also contains the EPA's evaluation of the Oregon SIP submission against the requirements of the Clean Air Act and Regional Haze Rule for the second implementation period of the regional haze program.

**C. Identification of Class I Areas**

Section 169A(b)(2) of the Clean Air Act requires each state in which any Class I area is located or “the emissions from which may reasonably be anticipated to cause or contribute to any impairment of visibility” in a Class I area to have a plan for making reasonable progress toward the national visibility goal. The Regional Haze Rule implements this statutory requirement at 40 CFR 51.308(f), which provides that each state's plan “must address regional haze in each mandatory Class I Federal area located within the State and in each mandatory Class I Federal area located outside the State that may be affected by emissions from within the State,” and (f)(2), which requires each state's plan to include a long-term strategy that addresses regional haze in such Class I areas.

**Oregon Class I Areas**

Oregon has 12 designated Class I areas, including Crater Lake National Park, managed by the National Parks Service, and 11 wilderness areas, managed by the U.S. Forest Service, or in the case of Hells Canyon Wilderness Area, managed jointly by the U.S. Forest Service and the Bureau of Land Management. [^119]

[^119] Section 169A of the Clean Air Act was established in 1977 to protect visibility in all wilderness areas over 5,000 acres and all national parks over 6,000 acres. 156 such areas were designated throughout the U.S.

**Mt. Hood Wilderness Area**

The Mt. Hood Wilderness Area consists of 47,160 acres on the slopes of Mt. Hood in the northern Oregon Cascades. Wilderness elevations range from 3,426 meters (m) (11,237 feet (ft.)) on the summit of Mt. Hood down to almost 600 m (2,000 ft.) at the western boundary. It is almost adjacent to the Portland, Oregon metropolitan area; the westernmost boundary is about 20 kilometers (km) east of the Portland, Oregon suburb of Sandy and 40 km from the heavily populated metropolitan center, elevation 100 m (300 ft.). Visitation to the Mt. Hood Wilderness Area is approximately 50,000 visitors a year, primarily between May and October. Most visitors come from the Portland/Vancouver area that has a population of approximately 2 million.

**Mt. Jefferson Wilderness Area**

The Mt. Jefferson Wilderness Area consists of 107,008 acres on the crest of the Cascade Range in central Oregon. Its southern boundary is a few km north of the northern boundary of the Mt. Washington Wilderness and it extends 40 to 50 km north along the Cascade crest. West of the crest, it consists primarily of the eastern side of the North Santiam River headwaters basin that connects to the Willamette Valley source region near Salem, Oregon, 100 km (60 miles (mi)) to the west. East of the crest it occupies the western slopes of the Metolius River drainage that connects eastern slopes with Deschutes River in eastern Oregon. The highest elevation is 3,200 m (10,497 ft.) at the summit of Mt. Jefferson in the northern part of the Wilderness. The lowest Wilderness elevations are near 1,000 m (3,000 ft.) along the western boundary in the North Santiam headwaters basin and along the eastern boundary in the Metolius River basin.

**Mt. Washington Wilderness Area**

The Mt. Washington Wilderness Area consists of 52,516 acres on the crest of the Cascade Range in central Oregon. Like the Three Sisters Wilderness that it borders to the south, it includes headwaters tributaries of the McKenzie River that flow west into the Willamette Valley near Eugene and connect the Wilderness with that source region. On the east side, eastern slopes of the Cascades descend to the Deschutes River near Bend. The highest Wilderness elevation is 2,376 m (7,794 ft.) at the summit of Mt. Washington. The lowest elevations are near 900 m (3,000 ft.) in the upper headwaters basin of the McKenzie River.

**Three Sisters Wilderness Area**

The Three Sisters Wilderness Area consists of 285,202 acres abreast the crest of the Cascade Range in central Oregon. It includes headwaters tributaries of the McKenzie River that flow west into the Willamette Valley near Eugene and connect the Wilderness with that source region. On the east side, streams flow east to the Deschutes River near Bend. The highest crest elevation is 3,158 m (10,358 ft.) at the summit of the South Sister. The lowest elevations are near 600 m (2,000 ft.) where the South Fork of the McKenzie River exits the Wilderness on the west boundary. This is about 500 m (1,600 ft.) above the Willamette Valley at Eugene 70 km (40 mi) west.

**Diamond Peak Wilderness Area**

The 52,337 acre Diamond Peak Wilderness Area straddles the Cascade Range 50 km (30 mi) north of Crater Lake National Park. The highest crest elevation in the Wilderness is 2,666 m (8,744 ft.) at Diamond Peak, which is also the highest summit in this region of the Cascade Range. The lowest elevations are near 1,450 m (5,000 ft.) where streams exit the Wilderness on the west side. On the east side, the Wilderness is bordered by mountain lakes with elevations from 1,459 m to 1,693 m (4,786 to 5,553 ft.). The area includes headwaters of the Middle Fork of the Willamette River that flows to the Willamette Valley near Eugene, elevation 100 m (300 ft.) and 90 km (60 mi) distant. Wilderness elevations are thus some 1,400 m (4,600 ft.) above the Willamette Valley floor. East of the Cascade crest, streams flow to the Deschutes River in eastern Oregon.

**Crater Lake National Park**

Crater Lake National Park is the only national park in Oregon. The park was established on May 22, 1902, and now consists of 183,315 acres. It is located in southwestern Oregon on the crest of the Cascade Mountain range, 100 miles east of the Pacific Ocean. The crater's rim elevations range from about 900 to 1,873 ft. above lake level. The highest park elevation is 8,929 ft. at the peak of Mt. Scott, in the eastern park area. The National Park includes headwaters of the Rogue River that flows southwest towards the Medford/Grants Pass area, and Sun Creek/Wood River that flows southeast to the Klamath Falls area.

**Mountain Lakes Wilderness Area**

The Mountain Lakes Wilderness Area, encompassing 23,071 acres, is a relatively small Class I area in southern Oregon, 50 km (30 mi) south of Crater Lake National Park. It consists of several peaks with a highest elevation of 2,502 m (8,208 ft.) at the crest of Aspen Butte. The lowest elevations are near 1,500 m (5,000 ft.). Primary drainages are Varney Creek and Moss Creek that flow into the Upper Klamath Lake, 3 km northeast of the Wilderness boundary.

**Gearhart Mountain Wilderness Area**

The Gearhart Mountain Wilderness Area consists of 22,809 acres on the flanks of Gearhart Mountain in south central Oregon, primarily the northern  slope and eastern drainages of Gearhart Mountain, the dominant topographic feature. Elevations range from near 5,900 ft. at the North Fork of the Sprague River in the northern Wilderness to 8,364 ft. at the summit of Gearhart Mountain.

**Kalmiopsis Wilderness Area**

The Kalmiopsis Wilderness Area consists of 179,700 acres and is located in the Klamath Mountains of southwestern Oregon, part of the coastal temperate rainforest zone that lies between the Pacific Ocean and the east side of the coast ranges in northwestern U.S. and Canada. Its western boundary is 20 to 25 km (12 to 15 mi) from the coast. Its easternmost extent is about 40 km (25 mi) from the coast. Elevations range from about 300 m (900 ft.) on the western boundary where the Chetco River exits the Wilderness towards the Pacific Ocean 25 to 30 miles further west, to 1,554 m (5,098 ft.) on Pearsoll Peak on the eastern Wilderness boundary. The terrain in the Wilderness is steep canyons and long broad ridges. The Wilderness is mostly west of the general crest of the coast range, thus exposed to precipitation caused by lifting of eastward moving maritime air, primarily during the winter. Precipitation ranges from 150 to 350 cm (60 to 140 inches (in)) annually, depending on elevation.

**Strawberry Mountain Wilderness Area**

The Strawberry Mountain Wilderness Area consists of 69,350 acres in eastern Oregon, just east of John Day. The Wilderness comprises most of the Strawberry Mountain Range. The terrain is rugged, with elevations ranging from 1,220 m (4,000 ft.) to 2,755 m (9,038 ft.) at the summit of Strawberry Mountain. The Wilderness borders the upper John Day River valley to the north.

**Eagle Cap Wilderness Area**

The Eagle Cap Wilderness Area consists of 360,275 acres in northeastern Oregon. The terrain is characterized by bare peaks and ridges and U-shaped glaciated valleys. Elevations range from 5,000 ft. in lower valleys to near 10,000 ft. at the highest mountain summits. The Lostine and Minam Rivers flow north from the center of the Wilderness towards Pendleton and the Columbia, 130 km northwest.

**Hells Canyon Wilderness Area**

The Hells Canyon Wilderness Area consists of 214,944 acres and is located on the Oregon-Idaho border. The Snake River divides the wilderness, with 131,133 acres in Oregon, and 83,811 acres in Idaho. The Snake River canyon is the deepest river gorge in North America. The higher terrain is located on the Oregon side. Popular Oregon-side viewpoints are McGraw, Hat Point, and Somers Point.

**Oregon Visibility Monitoring Network**

Haze species in Oregon are measured and analyzed via the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. [^120] Table 1 of this preamble lists the IMPROVE stations representing visibility at Oregon Class I areas. Due to the remote nature of some of the Class I areas, several areas share a common IMPROVE station.

[^120] IMPROVE website at *http://vista.cira.colostate.edu/Improve.*

| Monitor ID | Class I area | Sponsor | Years operated |
| --- | --- | --- | --- |
| MOHO | Mt. Hood Wilderness | U.S. Forest Service | 2000-present. |
| THSI | Mt. Jefferson Wilderness | U.S. Forest Service | 1993-present. |
| CRLA | Crater Lake National Park | National Parks Service | 1988-present. |
| KALM | Kalmiopsis Wilderness | U.S. Forest Service | 2000-present. |
| STAR | Strawberry Mountain Wilderness | U.S. Forest Service | 2000-present. |
| HECA | Hells Canyon Wilderness Area | U.S. Forest Service | 2000-present. |

**Identification of Class I Areas in Other States**

The Oregon Department of Environmental Quality (ODEQ) used a Q/d screening approach in developing a list of sources for potential four-factor analysis, as discussed in more detail in section IV.E.a of this preamble. Q/d is equal to the emissions (Q) in tons per year of visibility-impairing pollutants (NO <sub>X</sub> , SO <sub>2</sub> , and particulate matter less than 10 microns in diameter (PM <sub>10</sub> )) divided by the distance to a Class I area (d) in kilometers. The resulting ratio is commonly used as a metric to assess a source's potential visibility impacts on a particular Class I area. Importantly, ODEQ used permitted emissions limits, called Plant Site Emissions Limits (PSELs), [^121] for a facility in 2017 to calculate Q.

[^121] PSELs are used to protect ambient air quality standards, prevent significant deterioration of air quality, and to ensure protection of visibility. Establishing such a limit is a mandatory step in the Oregon permitting process. A PSEL is designed to be set at the actual baseline emissions from a source plus approved emissions increases and minus required emissions reductions. This design is intended to maintain a more realistic emissions inventory. Oregon uses a fixed baseline year of 1977 or 1978 (or a prior year if more representative of normal operation) and factors in all approved emissions increases and required emissions decreases since baseline, to set the allowable emissions in the PSEL. Increases and decreases since the baseline year do not affect the baseline, but are included in the difference between baseline and allowable emissions. Oregon's PSEL program is used, in part, to implement NSR permitting. For major NSR, if a PSEL is calculated at a level greater than an established significant emission rate (SER) over the baseline actual emission rate, an evaluation of the air quality impact and major NSR permitting are required. If not, the PSEL is set without further review (a construction permit may also be required). For minor NSR (State NSR), a similar calculation is conducted. If the difference is greater than the SER, an air quality analysis is required to evaluate whether ambient air quality standards and increments are protected. The air quality analysis results may require the source to reduce the airshed impact and/or comply with a tighter emission limit. See 82 FR 14654, March 22, 2017, p. 14661. Oregon's PSEL requirements are codified at OAR 340, Division 222. These requirements are approved into the Oregon SIP at 40 CFR 52.1970(c). Oregon imposes the PSEL requirements via its major and minor new source review permitting programs at OAR 340, Divisions 216 and 224. Thus, PSELs are applicable requirements included in Title V operating permits for major stationary sources in Oregon.

ODEQ determined that this approach based on permitted emissions or potential to emit was more rigorous and environmentally protective than relying  on actual 2017 emissions which could increase in the future. Using this approach, ODEQ identified Oregon facilities with a Q/d ≥ 5 based on PSELs as having potential visibility impacts on other states shown in table 2 of this preamble. [^122] Based on the Q/d calculation, two facilities, PGE Beaver/Port Westward I and Georgia Pacific-Wauna Mill potentially impact visibility in Mount Rainier National Park, Washington with Q/d values slightly higher than the most impacted Oregon Class I area, Mount Hood Wilderness. [^123] All other facilities have higher potential Q/d impacts on Oregon Class I areas than the respective out-of-state Class I areas. [^124] Descriptions of the controls imposed at the facilities listed in table 2 are contained in section IV.E.b. of this preamble.

[^122] While PGE Boardman's emissions in 2017 would have screened the facility into four-factor analysis based on the facility PSELs, and actual emissions, this facility closed operations in 2020. The closure of this facility, the last coal-fired power plant in Oregon, was a product of the first round of Regional Haze planning.

[^123] Please see the EPA's evaluation of 40 CFR 51.308(f)(3)(ii)(B) for Mount Rainier National Park under section IV.F of this preamble.

[^124] April 29, 2022, Oregon SIP submission, Chapters 3.1. Q/d screening process and 3.3. Impact of facilities in other states on Oregon Class I areas.

| Facility name | Closest non-Oregon Class I area | Actual | Q/d PSEL | Nearest Oregon Class I area | Actual | Q/d PSEL |
| --- | --- | --- | --- | --- | --- | --- |
| A Division of Cascades Holding US Inc | Mount Adams Wilderness, WA | 2.69 | 56.77 | Mount Hood Wilderness | 3.02 | 63.72 |
| Ash Grove Cement Company | Sawtooth Wilderness, ID | 5.31 | 11.01 | Eagle Cap Wilderness | 18.54 | 38.47 |
| Beaver Plant/Port Westward I Plant | Mount Rainier NP, WA | 3.75 | 40.15 | Mount Hood Wilderness | 3.24 | 34.60 |
| Biomass One, L.P | Marble Mountain Wilderness, CA | 3.06 | 6.33 | Mountain Lakes Wilderness | 4.77 | 9.86 |
| Boise Cascade-Medford | Marble Mountain Wilderness, CA | 3.25 | 5.45 | Mountain Lakes Wilderness | 4.19 | 7.02 |
| Collins Products, L.L.C | Lava Beds/Schonchin Wilderness, CA | 2.43 | 5.48 | Mountain Lakes Wilderness | 4.78 | 10.82 |
| EVRAZ Inc. NA | Mount Adams Wilderness, WA | 2.44 | 8.14 | Mount Hood Wilderness | 3.57 | 11.92 |
| Georgia Pacific-Wauna Mill | Mount Rainier NP, WA | 17.94 | 31.48 | Mount Hood Wilderness | 16.18 | 28.38 |
| Georgia-Pacific-Toledo | Mount Adams Wilderness, WA | 4.64 | 12.04 | Three Sisters Wilderness | 7.83 | 20.33 |
| Halsey Pulp Mill | Mount Adams Wilderness, WA | 3.11 | 8.32 | Three Sisters Wilderness | 8.86 | 23.69 |
| Klamath Cogeneration Project | Lava Beds/Schonchin Wilderness, CA | 3.66 | 8.69 | Mountain Lakes Wilderness | 6.91 | 16.40 |
| Oregon City Compressor Station | Mount Adams Wilderness, WA | 1.49 | 5.53 | Mount Hood Wilderness | 3.64 | 13.49 |
| Owens-Brockway Glass Container Inc | Mount Adams Wilderness, WA | 6.13 | 11.85 | Mount Hood Wilderness | 10.86 | 21.00 |
| Roseburg Forest Products—Dillard | Redwood NP, CA | 10.39 | 16.70 | Kalmiopsis Wilderness | 19.07 | 30.67 |
| Willamette Falls Paper Company | Mount Adams Wilderness, WA | 1.75 | 12.23 | Mount Hood Wilderness | 3.79 | 26.46 |

**D. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress**

Section 51.308(f)(1) requires states to determine the following for “each mandatory Class I Federal area located within the State:” baseline visibility conditions for the most impaired and clearest days, natural visibility conditions for the most impaired and clearest days, progress to date for the most impaired and clearest days, the differences between current visibility conditions and natural visibility conditions, and the uniform rate of progress. This section also provides the option for states to propose adjustments to the uniform rate of progress line for a Class I area to account for visibility impacts from anthropogenic sources outside the U.S. and/or the impacts from wildland prescribed fires that were conducted for certain, specified objectives. [^125]

[^125] 40 CFR 51.308(f)(1)(vi)(B).

**Tracking Visibility in Oregon**

Oregon's SIP submission addresses baseline, current and natural visibility conditions for each of these IMPROVE stations as required by the 2017 Regional Haze Rule and the EPA's technical guidance on tracking visibility progress. ODEQ reviewed visibility data from 2000 through 2018 and determined that current visibility at all Class I areas for both the clearest and most impaired days has improved since the baseline period. In addition, all areas have met the uniform rate of progress (URP) for 2018. [^126] Additionally, many Class I areas such as the Mt. Hood, Strawberry Mountain, Eagle Cap, and Hells Canyon wilderness areas are already meeting the 2028 URP for the Most Impaired Days (MID) based on current 2014-2018 monitoring data. Oregon did not choose to adjust its URP for international anthropogenic impacts or to account for the impacts of wildland prescribed fires resulting in a more stringent, environmentally protective URP glidepath as discussed in section IV.F. of this preamble.

[^126] April 29, 2022 Oregon SIP submission. Tables 2-6 and 2-7.

[^127] ODEQ used data drawn from “Availability of Modeling Data and Associated Technical Support Document for the EPA's Updated 2028 Visibility Air Quality Modeling” (EPA 2019) with corrected data as applicable from the June 2020 EPA Memo, “Technical addendum including updated visibility data through 2018 for the memo titled `Recommendation for the Use of Patched and Substituted Data and Clarification of Data Completeness for Tracking Visibility Progress for the Second Implementation Period of the Regional Haze Program.”

| Monitor ID | Class I area | Baseline | 2018 URP | Current | 2028 URP | Natural |
| --- | --- | --- | --- | --- | --- | --- |
|  |  |  |  |  |  |  |
| MOHO | Mt. Hood Wilderness Area | 12.10 | 10.81 | 9.27 | 9.90 | 6.59 |
| THSI | Mt. Jefferson, Mt. Washington, and Three Sisters Wilderness Areas | 12.80 | 11.52 | 11.28 | 10.60 | 7.30 |
| CRLA | Crater Lake National Park; Diamond Peak, Mountain Lakes, and Gearhart Mountain Wilderness Areas | 9.36 | 8.38 | 7.98 | 7.70 | 5.16 |
| KALM | Kalmiopsis Wilderness Area | 13.34 | 12.04 | 11.97 | 11.13 | 7.78 |
| STAR | Strawberry Mountain and Eagle Cap Wilderness Areas | 14.53 | 12.68 | 11.19 | 11.35 | 6.58 |
| HECA | Hells Canyon Wilderness Area | 16.51 | 14.19 | 12.33 | 12.53 | 6.57 |
|  |  |  |  |  |  |  |
| MOHO | Mt. Hood Wilderness Area | 2.17 | Not applicable | 1.39 | Not applicable | 0.88 |
| THSI | Mt. Jefferson, Mt. Washington, and Three Sisters Wilderness Areas | 3.04 | NA | 2.61 | NA | 1.86 |
| CRLA | Crater Lake National Park; Diamond Peak, Mountain Lakes, and Gearhart Mountain Wilderness Areas | 1.69 | NA | 1.05 | NA | 0.10 |
| KALM | Kalmiopsis Wilderness Area | 6.27 | NA | 5.90 | NA | 3.70 |
| STAR | Strawberry Mountain and Eagle Cap Wilderness Areas | 4.49 | NA | 2.79 | NA | 1.48 |
| HECA | Hells Canyon Wilderness Area | 5.52 | NA | 4.00 | NA | 2.52 |

The EPA is proposing to find that Oregon has submitted a regional haze plan that meets the requirements of 40 CFR 51.308(f)(1) related to the calculations of baseline, current, and natural visibility conditions; progress to date; and the uniform rate of progress for the second implementation period.

**E. Long-Term Strategy for Regional Haze**

**a. The Oregon Long-Term Strategy**

Each state having a Class I area within its borders or emissions that may affect visibility in a Class I area must develop a long-term strategy for making reasonable progress towards the national visibility goal. [^128] As explained in the background discussion in section II. of this preamble, reasonable progress is achieved when all states contributing to visibility impairment in a Class I area are implementing the measures determined—through application of the four statutory factors to sources of visibility impairing pollutants—to be necessary to make reasonable progress. [^129] Each state's long-term strategy must include the enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress. [^130] All new ( *i.e.,* additional) measures that are the outcome of four-factor analyses are necessary to make reasonable progress and must be in the long-term strategy. If the outcome of a four-factor analysis and other measures necessary to make reasonable progress is that no new measures are reasonable for a source, that source's existing measures are necessary to make reasonable progress, unless the state can demonstrate that the source will continue to implement those measures and will not increase its emission rate. Existing measures that are necessary to make reasonable progress must also be in the long-term strategy. In developing its long-term strategies, a state must also consider five additional factors. [^131] As part of its reasonable progress determinations, the state must describe the criteria used to determine which sources or group of sources were evaluated ( *i.e.,* subjected to four-factor analysis) for the second implementation period and how the four factors were taken into consideration in selecting the emission reduction measures for inclusion in the long-term strategy. [^132]

[^128] Clean Air Act section 169A(b)(2)(B).

[^129] 40 CFR 51.308(f)(2)(i).

[^130] 40 CFR 51.308(f)(2).

[^131] 40 CFR 51.308(f)(2)(iv).

[^132] 40 CFR 51.308(f)(2)(iii).

The following paragraphs summarize how the Oregon submissions addressed the requirements of 40 CFR 51.308(f)(2)(i). The EPA's evaluation of the Oregon submission is contained in section IV.E.b. of this preamble. The Oregon submission includes analysis and modeling conducted by the State, the EPA and the WRAP, a narrative description of the State's long-term strategy, and enforceable emissions limitations embodied in State administrative orders and permits. [^133]

[^133] April 29, 2022 Oregon SIP submission, Chapter 2.5.1 Estimated future projected emissions.

States may rely on technical information developed by the regional planning organizations of which they are members to select sources for four-factor analysis and to conduct that analysis, as well as to satisfy the documentation requirements under 40 CFR 51.308(f). Where a regional planning organization has performed source selection and/or four-factor analyses (or considered the five additional factors in 40 CFR 51.308(f)(2)(iv)) for its member states, those states may rely on the regional planning organization's analyses for the purpose of satisfying the requirements of 40 CFR 51.308(f)(2)(i) so long as the states have a reasonable basis to do so and all state participants in the regional planning organization process have approved the technical analyses. [^134] States may also satisfy the requirement of 40 CFR 51.308(f)(2)(ii) to engage in interstate consultation with other states that have emissions that are reasonably anticipated to contribute to visibility impairment in a given Class I area under the auspices of intra- and inter-regional planning organization engagement.

[^134] 40 CFR 51.308(f)(3)(iii).

The WRAP is the regional planning organization to which Oregon belongs. The WRAP coordinated technical services, modeling, data management, and consulting during the second planning period. The WRAP developed technical tools, emission inventories, and air quality modeling with input and involvement from states in the region. Oregon has participated actively in the WRAP and used WRAP technical products to help develop the Oregon submissions.

In the submissions, Oregon conducted technical analyses to identify sources and source categories with the largest potential to contribute to visibility impairment at Class I areas in Oregon and other states. Based on the composition of regional haze forming pollutants at the IMPROVE stations, ODEQ determined that the majority of U.S. anthropogenic contribution to  regional haze in Oregon Class I areas is ammonium nitrate. This varies seasonally and by monitor. [^135] Statewide, NO <sub>X</sub> emissions are primarily from mobile sources, at about 80% of the inventory, with another 13% of the inventory coming from fuel combustion from area and stationary sources. [^136] At some monitors, such as the IMPROVE stations in the Cascades (THIS and CRLA) and Kalmiopsis (KALM), ammonium sulfate is a proportionally larger contributor to regional haze formation. ODEQ determined the ammonium sulfate contribution is primarily from international anthropogenic sources and is projected to decrease by 77% due to new standards for international marine shipping fuels which became effective in 2020. [^137] Specifically, in 2010, the International Marine Organization (IMO) established emission standards for vessels operating in designated waters off the coast of North America. MARPOL Annex VI is codified at 33 U.S.C. 1901 *et seq.* Pursuant to 33 U.S.C. 1907, it is unlawful to act in violation of the MARPOL Protocol. The North American Emissions Control Area (ECA) covers most coastal areas of the United States. Vessels operating in the area must burn low sulfur marine fuel, 1,000 ppm sulfur content (0.10% sulfur by weight). In addition, as of January 1, 2020, the IMO limited sulfur in fuel for ships operating outside designated ECAs to 5,000 ppm sulfur content (0.50% sulfur by weight). This limit represents a substantial reduction from the prior IMO limit of 35,000 ppm sulfur content (3.5% sulfur by weight). Fuel sulfur limits are codified at 40 CFR part 1043. See 84 FR 69335, 69336 (December 18, 2019). The levels of organic mass and elemental carbon, likely from wildfire, prescribed burning, and anthropogenic and biogenic sources of volatile organic compounds vary at all Oregon IMPROVE stations from 2000 to 2018 but show no significant trend. [^138]

[^135] April 29, 2022 Oregon SIP submission, Chapter 2.4 Pollutant Components of Visibility Impairment.

[^136] April 29, 2022 Oregon SIP submission, Chapter 2.3 Emissions Inventory Analysis.

[^137] International Marine Organization. 2020. A Breath of Fresh Air. *https://wwwcdn.imo.org/localresources/en/MediaCentre/HotTopics/Documents/Sulphur%202020%20infographic%202%20page.pdf.*

[^138] April 29, 2022 Oregon SIP submission, Chapter 2.4 Pollutant Components of Visibility Impairment.

In addition to selecting and evaluating stationary sources for four-factor analysis, Oregon also used EPA emissions inventory data from 2017 to review emissions from mobile sources such as nonroad vehicles ( *e.g.,* construction, agriculture, lawn and garden, recreational equipment) and onroad vehicles ( *e.g.* commercial trucks, passenger cars and trucks), as well as agriculture, fugitive dust, marine shipping, oil and gas, prescribed fires, and railroads. The submissions address these sectors and their potential to contribute to visibility impairment in Chapter 2.3. *Emissions Inventory Analysis* and Chapter 4 *Long-term Strategy.*

With respect to analyzing stationary sources, Oregon used a Q/d methodology to select sources for evaluation under the four statutory factors. This methodology does not take into consideration topography, transport direction/pathway and dispersion, and photochemical processes. However, it is an adequate tool for source selection and is consistent with the EPA guidance. Specifically, Oregon's submission determined “Q/d” where “Q” is a source's emissions and “d” is the distance from the source to the nearest Class I area. Oregon identified permitted point sources by their Q/d values, calculated using the sum of all emissions of sulfur dioxide, nitrogen oxides and particulate matter less than 10 microns in diameter (as measured in tons per year), divided by the distance to a Class I area (measured in kilometers from the facility to the nearest boundary of the Class I area) for all Class I areas within 400 km of the source. Rather than using actual emissions to screen facilities in, Oregon was more conservative and used permitted emissions, called Plant Site Emissions Limits (PSELs) to effectively screen in more sources than would otherwise have been identified. [^139]

[^139] Save for certain exceptions, PSELs are included in all Air Contaminant Discharge Permits (ACDP) and Title V Operating Permits issued to sources in Oregon. See OAR 340-222-0020. This program is approved into the Oregon SIP. 40 CFR 52.1970(c). Oregon establishes PSELs for multiple pollutants, including SO <sub>2</sub> , NO <sub>X</sub> , PM <sub>10</sub> , and PM <sub>2.5</sub> . *Id.* Sources are required to monitor pollutant emissions and comply with the PSELs. 340-222-0080. PSELs serve as a basis for, among other things, assuring compliance with ambient air quality standards and Prevention of Significant Deterioration increments. OAR 340-222-0020. ODEQ sets PSELs based on a variety of factors; in general, PSELs are set at levels above the projected actual or actual emissions of the source. OAR 340-222-0041; 0042.

As discussed in more detail in section IV.E.b of this preamble, Oregon selected 32 sources for review using the Q/d screening methodology. Of these 32 sources, several incorporated enforceable emissions limits into their permits or in agreed orders resulting in PSELs below the screening threshold, and several had recently imposed controls already in place, with the remaining 23 sources conducting four-factor analyses. ODEQ reviewed the four-factor analyses submitted by the sources and found that 6 of the sources that additional controls were above the $10,000 cost per ton reduction threshold established by ODEQ. For the remaining 17 sources, ODEQ determined that additional controls might be cost effective and initiated a second round of review evaluating 43 emissions units and a total of 62 control devices. During this second round of review, an additional 4 sources incorporated facility-wide enforceable emissions limits effectively lowering PSELs below the screening threshold, and ODEQ negotiated permit modifications or agreed orders to install control devices or other emissions reductions at the remaining 13 facilities described in more detail in section IV.E.b. of this preamble.

After reviewing the submissions, the EPA proposes to determine that Oregon's long-term strategy includes the enforceable emissions limitations, compliance schedules, and other measures necessary to make reasonable progress. By extension, the EPA proposes to determine that Oregon's selection of sources for evaluation under the four statutory factors was reasonable and consistent with the requirements of the RHR and proposes to determine that Oregon determined the controls necessary for reasonable progress based on a reasonable consideration of the four factors, as described in the evaluation below.

**b. The EPA's Evaluation of the Oregon Long-Term Strategy**

The EPA is proposing to find that Oregon has satisfied the requirements of 40 CFR 51.308(f)(2)(i) related to evaluating sources and determining the emission reduction measures that are necessary to make reasonable progress by considering the four statutory factors. The EPA is proposing to find that Oregon has satisfied the four-factor analysis requirement through its evaluation and actions documented in the Oregon regional haze plan for the second planning period. Section 51.308(f)(2)(i) requires states to evaluate and determine the emission reduction measures that are necessary to make reasonable progress by considering the four statutory factors to sources in a control analysis. As laid out in further detail in the following paragraphs of this preamble, the EPA is proposing to find that the Oregon submission, as supplemented, satisfies the requirement of 40 CFR 51.308(f)(2)(i). The emission reduction measures that are necessary to  make reasonable progress must be included in the long-term strategy, *i.e.,* in the Oregon SIP. 40 CFR 51.308(f)(2).

**Division 223 Regional Haze Rules**

On May 28, 2021, Oregon opened public comment on revisions to the Division 223 Regional Haze rules to update the provisions for the second regional haze planning period. [^140] The Oregon Environmental Quality Commission adopted the revisions to the Division 223 Regional Haze rules at its July 22-23, 2021 meeting, and the rules became effective July 23, 2021. [^141] A detailed redline/strikeout of the rule revisions is included in the docket for this action. [^142] The revisions removed outdated BART provisions from the first planning period, including source-specific requirements in Oregon Administrative Rules (OAR) 340-223-0040 for the Amalgamated Sugar Company which ceased operation on December 9, 2010, and closed permanently in September 2016. [^143] The revisions also repealed outdated BART provisions in OAR 340-223-0030 through 340-223-0080 for the Portland General Electric (PGE) coal-fired power plant in Boardman which ceased operation on October 15, 2020, pursuant to the requirements of the regional haze plan for the first implementation period. Documentation of the closure of the coal-fired power plant is included in the docket for this action. [^144]

[^140] 016_4.1.2 SOS.Notice.FilingReceipt.pdf included in the docket for this action.

[^141] 018_4.2.2 SOS.Filing.Receipt.DEQ_14-2021.pdf included in the docket for this action.

[^142] 004_3.1 RHSIP2021.Rules_.doc included in the docket for this action.

[^143] April 29, 2022 Oregon SIP submission, Chapter 2.1.1 Status of implementation of control measures included in the original regional haze SIP.

[^144] See 200_boardman closure_25-0016-TV-01_AR_2020, 201_boardman closure_25-0016-TV-01_AR_2021, 202_boardman closure_AIRS_AFS Search _US EPA, 203_2022 PSD permit_boardman carty_25-0016-ST-02_PM_2022_3.

In addition to removing outdated provisions, Oregon added new rule provisions to implement the regional haze program for the second implementation period. OAR 340-223-0100 *Screening Methodology for Sources for Round II of Regional Haze* established the screening methodology for stationary sources in the regional haze second planning period. Pursuant to this rulemaking sources were required to undergo review if the source's Q/d was greater than 5, where Q equals the sum of the source's PSELs for NO <sub>X,</sub> SO <sub>2</sub> , and PM <sub>10</sub> .

OAR 340-223-0110 *Options for Compliance with Round II of Regional Haze* imposed the obligation on screened sources to conduct four-factor analyses and established the process for imposition of controls determined by ODEQ to be cost effective based on those four-factor analyses, using a cost-effectiveness threshold of $10,000 or less per ton of reductions for any single or combination of regional haze pollutants. Specifically, OAR 340-223-0110(1) requires each source screened into review to submit a four-factor analysis and install controls determined by ODEQ to be cost effective following ODEQ's adjustment and review of the four-factor analysis. OAR 340-223-0110(2) allows alternative compliance options under an agreed order with ODEQ (stipulated agreement and final order or SAFO) as summarized below:

• Accept federally enforceable reductions of combined plant site emission limits of regional haze pollutants to bring the source's Q/d below 5.00. A source may take a PSEL reduction below the generic PSEL to achieve an overall PSEL of regional haze pollutants below a Q/d of 5.00. A source's Q/d will be considered to be brought below 5.00 when Q/d is below 5.00 using the calculation in OAR 340-223-0100(2), except that the Q factor shall be calculated by adding the plant site emission limits for regional haze pollutants as stated in the stipulated agreement and final order;

• Install controls identified by the source in a four-factor analysis as cost-effective for that source for reducing regional haze pollutants. ODEQ must agree that the controls identified will result in the greatest cost-effective emissions reduction at the identified emissions unit and ODEQ must establish a timeline for installation of those controls that is the fastest practicable timeline for installation of the identified controls and that is no later than July 31, 2026;

• Install controls or reduce emissions for regional haze pollutants that ODEQ determines, in its sole discretion, provide equivalent emissions reductions to controls that would be identified as cost effective for that source following the adjustment and review of a four-factor analysis. ODEQ must establish a timeline for installation of those controls that is the fastest practicable timeline for installation of the identified controls and that is no later than July 31, 2026;

• Maintain controls that the source has already installed to control regional haze pollutants or maintain reduced emissions of regional haze pollutants that ODEQ determines, in its sole discretion, have provided and will continue to provide equivalent emissions reductions to controls that would be identified as cost effective for that source following adjustment and review of a four-factor analysis; or

• Replace an emissions unit with a new emissions unit that meets the emission limits and requirements of the most recent applicable standard in place at the time of the permitting of the new emissions unit. ODEQ must establish a timeline for installation of the new emissions unit that is the fastest practicable timeline for installation of the new emissions unit and that is no later than July 31, 2031.

OAR 340-223-0120 *Four Factor Analysis* established the requirements sources must follow in conducting the four-factor analyses consistent with the Clean Air Act four statutory factors and provides ODEQ with authority to request additional information or adjust the four-factor analyses for consistency. Lastly, OAR 340-223-0130 *Final Orders Ordering Compliance with Round II of Regional Haze* provides ODEQ unilateral order authority to address those sources that do not enter into a stipulated agreement and final order (SAFO) under OAR 340-223-0110(2). OAR 340-223-0130 also outlines the contested case hearing process for sources that challenge the unilateral orders issued by ODEQ.

We have reviewed the revisions to the Division 223 Regional Haze Rules and we are proposing to determine that they provide Oregon with adequate authority to implement the regional haze program and are consistent with CAA requirements and the EPA's Regional Haze Rule. ODEQ submitted the revised Division 223 Regional Haze Rules for incorporation by reference into the SIP at 40 CFR 52.1970(c) *EPA approved regulations and statutes* and requested that the EPA remove from the SIP the outdated source-specific BART provisions for the Amalgamated Sugar Company and the PGE coal-fired power plant in Boardman, which closed pursuant to the regional haze plan for the first implementation period. We are proposing to approve this request and incorporate by reference the submitted revised rules.

**Stationary Source Screening**

Pursuant to OAR 340-223-0100 *Screening Methodology for Sources for Round II of Regional Haze,* ODEQ identified 32 facilities for analysis using the four factors. As described in the previous paragraphs, the PGE coal-fired power plant in Boardman ceased operation on October 15, 2020, and ODEQ removed the facility from the initial list of 32 facilities. The remaining operations onsite are known as Carty  Generating Station with an expected maximum Q/d of slightly over 1.00. [^145]

[^145] The Carty Generating Station is a 450 megawatt (MW), combined-cycle natural gas-fueled electric generating power plant, and includes a not-yet-constructed 50 MW solar PV electric power generating unit (Carty Solar Farm) on 315 acres (0.49 sq. miles). See *https://www.oregon.gov/energy/facilities-safety/facilities/pages/cgs.aspx.*

**Limits To Align PSELs to the Screening Threshold**

As previously noted, ODEQ took a more inclusive approach of using permitted emissions limits, PSELs, to screen facilities for source selection. This yielded a much larger pool of facilities in the initial screening rather than using projected actuals as suggested by the 2019 Guidance. [^146] OAR 340-223-0110(2)(b)(A) allows ODEQ to enter into an agreement with a source to “accept federally enforceable reductions of combined plant site emission limits of round II regional haze pollutants to bring the source's Q/d below 5.00.” As noted in ODEQ's April 29, 2021, SIP submission, “if a facility's actual emissions were below the screening threshold and potential emissions above the screening threshold, ODEQ provided the source an opportunity to either reduce pollutant-specific PSELs or take a limit on combined NO <sub>X</sub> , SO <sub>2</sub> , and PM <sub>10</sub> PSELs such that Q/d would be less than 5.00.” [^147] If a source chose the option to reduce PSELs, OAR 340-223-0110(2)(b)(A) exempted the source from further control analysis. Importantly, OAR 340-223-0110(2)(b)(A) allows sources to reduce PSELs as a compliance option at any point in the process from initial screening through final agreements. [^148] To make the limits Federally enforceable and permanent, ODEQ submitted the SAFOs and/or permit conditions listed in table 7 for incorporation into the SIP in 40 CFR 52.1970(d) *EPA approved state source-specific requirements.*

[^146] 2019 Guidance at 17.

[^147] April 29, 2022 Oregon SIP submission, Chapter 3.4. Four Factor Analysis.

[^148] April 29, 2022 Oregon SIP submission, Chapter 6.6. Public Comments and Responses, at page 147.

[^149] April 29, 2022 Oregon SIP submission, Chapter 3.7 Facility-specific findings and results.

[^150] ODEQ reviewed Kingsford Manufacturing Company which originally screened into analysis with a Q/d = 8.39 based on actual emissions as reported to the 2017 National Emissions Inventory (NEI) because a 2017 PSEL was not available at that time. However, in a letter dated May 22, 2020, ODEQ acknowledged a 2019 permit modification that had already lowered PSELs for NO <sub>X</sub> , SO <sub>2</sub> , and PM <sub>10</sub> to a Q/d = 4.02. [^150] As part of the November 22, 2023 supplement, ODEQ submitted revised permit conditions for the Kingsford Manufacturing Company that limit the combined PSELs and unassigned emissions to 304 tons per year yielding a Q/d = 4.98.

[^151] Alternatively, under Order 01-0038, the facility, up until July 2026, could opt to commit to replace units EU1 and EU2 with new technology by July 31, 2031, that would reduce Round 2 regional haze pollutants. The technology would have to meet the emission limits and requirements of the most recent New Source Performance Standard in place at the time of the permittee submitting a permit application for the project. PSELs for Round 2 regional haze pollutants for the replacement shall be no more than 201 tons/year.

The EPA proposes to determine that Oregon's source selection was reasonable and consistent with the requirements of 40 CFR 51.308(f)(2)(i). ODEQ included a thorough description of its source selection methodology. ODEQ selected 23 sources for analysis under the four factors. Considering these sources' PSELs and recent actual emissions, ODEQ's source selection methodology targeted the sources with the highest potential to impair visibility at mandatory Class 1 areas. Conversely, those sources ODEQ screened out have comparatively limited potential impacts on visibility, specifically, all facilities that accepted emission limits to screen out of analysis would have been screened out of analysis using a Q/d <5 of actual emissions. Thus, the EPA proposes to determine that Oregon's application of OAR 340-223-0110(2)(b)(A) is a reasonable means of preventing future emissions growth for facilities with relatively low Q/d values based on actual current emissions.

| Facility | 2017 Actual Q/d | 2017 PSEL Q/d | Outcome |
| --- | --- | --- | --- |
| PGE Boardman | 38.24 | 116.21 | No four-factor analysis (FFA). Facility shut down coal-fired operations in 2020. |
| Ash Grove Cement Company | 18.54 | 38.47 | No FFA. ODEQ determined 2013 consent decree with the EPA represented existing effective controls. |
| Klamath Energy LLC | 6.91 | 16.40 | No FFA. ODEQ determined that newly installed controls yield a Q/d <5.00. |
| Kingsford Manufacturing Company | 8.38 | NA | No FFA—lowered PSEL to Q/d <5.00. |
| Cascades Tissue Group: A Division of Cascades Holding US Inc | 3.02 | 63.72 | No FFA—lowered PSEL to Q/d <5.00. |
| Timber Products Co. Limited Partnership | 1.63 | 6.07 | No FFA—lowered PSEL to Q/d <5.00. |
| PGE Beaver Plant/Port Westward I Plant | 3.24 | 34.60 | No FFA—lowered PSEL to Q/d <5.00. |
| Roseburg Forest Products—Riddle Plywood | 2.10 | 5.29 | No FFA—lowered PSEL to Q/d <5.00. |
| Roseburg Forest Products—Medford MDF | 2.91 | 8.84 | No FFA—lowered PSEL to Q/d <5.00. |
| Boise Cascade Wood Products, LLC—Medford | 4.19 | 7.02 | Conducted FFA—then lowered PSEL to Q/d <5.00. |
| Gas Transmission Northwest LLC—Compressor Station 12 | 2.33 | 14.13 | Conducted FFA—then lowered PSEL to Q/d <5.00. |
| JELD-WEN | 2.13 | 6.30 | Conducted FFA—then lowered PSEL to Q/d <5.00. |
| Northwest Pipeline LLC—Baker Compressor Station | 4.02 | 14.81 | Conducted FFA—then lowered PSEL to Q/d <5.00. |
| Pacific Wood Laminates, Inc | 8.29 | 12.50 | Conducted FFA—ODEQ determined no controls <$10K. |
| Swanson Group Mfg. LLC | 4.16 | 6.39 | Conducted FFA—ODEQ determined no controls <$10K. |
| Ochoco Lumber Company | 4.60 | 14.19 | Conducted FFA—ODEQ determined no controls <$10K. |
| Columbia Forest Products, Inc | 4.10 | 7.75 | Conducted FFA—ODEQ determined no controls <$10K. |
| Collins Products, L.L.C | 4.78 | 10.82 | Conducted FFA—ODEQ determined no controls <$10K. |
| Woodgrain Millwork LLC—Particleboard | 13.32 | 18.41 | Conducted FFA—ODEQ determined no controls <$10K |
| Gilchrist Forest Products | 8.42 | 15.74 | Conducted FFA—source determined controls cost effective. Modified permit to incorporate controls. |
| Owens-Brockway Glass Container Inc | 10.86 | 21.00 | Conducted FFA—agreed order to impose additional controls. |
| Boise Cascade Wood Products, LLC—Elgin Complex | 10.08 | 15.04 | Conducted FFA—agreed order to impose additional controls. |
| Georgia Pacific—Wauna Mill | 16.18 | 28.38 | Conducted FFA—agreed order to impose additional controls. |
| Cascade Pacific Pulp, LLC—Halsey Pulp Mill | 8.86 | 23.69 | Conducted FFA—agreed order to impose additional controls. |
| Gas Transmission Northwest LLC—Compressor Station 13 | 2.34 | 19.68 | Conducted FFA—agreed order to impose additional controls. |
| International Paper—Springfield | 16.51 | 67.24 | Conducted FFA—agreed order to impose additional controls. |
| Georgia-Pacific—Toledo LLC | 7.83 | 20.33 | Conducted FFA—agreed order to impose additional controls. |
| Northwest Pipeline LLC—Oregon City Compressor Station | 3.64 | 13.49 | Conducted FFA—agreed order to impose additional controls. |
| EVRAZ Inc. NA | 3.57 | 11.92 | Conducted FFA—agreed order to impose additional controls. |
| Biomass One, L.P | 4.77 | 9.86 | Conducted FFA—agreed order to impose additional controls. |
| Roseburg Forest Products—Dillard | 19.07 | 30.67 | Conducted FFA—agreed order to impose additional controls. |
| Willamette Falls Paper Company | 3.79 | 26.46 | Conducted FFA—agreed order to impose additional controls. |

**Sources That Already Have Effective Emission Control Technology in Place**

In certain circumstances, states may properly determine that a particular facility already has effective emission control technology in place. [^152] A state that does not select a source or sources for this reason should explain why the decision is consistent with the requirement to make reasonable progress. ODEQ determined that 2 facilities of the originally screened 32 met this criterion, Klamath Energy LLC and Ash Grove Cement.

[^152] 2019 Guidance at 22; 2021 Clarifications Memo at 9.

In a May 28, 2020, letter from ODEQ to Klamath Energy, ODEQ acknowledged plans by the facility to install ultra low-NO <sub>X</sub> burners on the facility's combined cycle combustion turbines (emissions units CT1 and CT2). These planned upgrades are in addition to Selective Catalytic Reduction (SCR) control technology already in place at the CT1 and CT2 units and other associated units, CT3 through CT6. ODEQ estimated that the planned upgrades would reduce the facility combined PM <sub>10</sub> , SO <sub>2</sub> , and NO <sub>X</sub> PSELs to 122 tons per year, yielding a Q/d less than 5.00. Importantly, the 2020 permit modification did not include revised PSELs, but relied on installation of planned controls by January 1, 2022, as required under condition 3.a. of the permit modification. Therefore, as part of the November 22, 2023 supplement to the regional haze plan, ODEQ submitted relevant portions of the December 8, 2020, permit modification detailing installation and operation of the ultra low-NO <sub>X</sub> combustors, as well as relevant conditions from the June 12 2017, permit to include the existing pollution control devices for the remaining emissions units for incorporation by reference into the SIP. In reviewing the planned controls for these units, as well as the existing controls for other units at the facility, we are proposing to determine the facility has effective emission control technology in place, and those controls and associated emissions limits are included in the SIP.

As discussed in Oregon's May 18, 2020, letter included in the docket for this action, the Ash Grove Cement, Durkee plant recently underwent a control analysis and ODEQ determined that no additional controls required through the regional haze second implementation period were likely to be effective or reasonable. [^153] To reach this determination, ODEQ reviewed information the facility sent regarding particulate matter emissions which are controlled by a recently installed baghouse system in accordance with the 2018 Portland Cement National Emission Standards for Hazardous Air Pollutants (NESHAP) revisions, the facility's Air Contaminant Discharge Permit (ACDP) from 2017 (Permit No. 01-0029-CS-01), and the 2017 administrative amendment to the permit (Permit No. 01-0029-TV-01). [^154] In addition, ODEQ considered the enforcement actions that the EPA took on Portland Cement companies in conjunction with the State of Oregon and the resulting consent decrees to further control emissions. [^155] With respect to the plant in Durkee, the consent decree required installation and continuous operation of selective noncatalytic reduction (SNCR) at Kiln 1, a 30-day rolling average emission limit of 2 pounds NO <sub>X</sub> per ton of clinker, and a 3-hour average emission limit of 0.4 pounds SO <sub>2</sub> per ton of clinker. Based on the controls from the 2018 NESHAP and the consent decree requirements, ODEQ determined that the facility has effective emission control technology in place. We are proposing to concur with that determination for this planning period. ODEQ submitted the October 16, 2020, Title V permit for Ash Grove Cement for the incorporation of relevant permit conditions in the SIP for the existing controls and emissions limits related to regional haze.

[^153] 100_haze-AshGroveCement-Durkee.pdf.

[^154] April 29, 2022 Oregon SIP submission, Chapter 3.7.2 Ash Grove Cement Co, Durkee (01-0029).

[^155] 100a_ashgrove-cd.pdf included in the docket for this action.

**Facilities With Additional Controls**

Under OAR 340-223-0110(1) all sources subject to the requirements of the regional haze second implementation period, as determined in OAR 340-223-0100 *Screening Methodology for Sources for Round II of Regional Haze,* were required to submit a four-factor analysis consistent with the provisions of OAR 340-223-0120 *Four Factor Analysis.* Specifically, sources were required to conduct four-factor analyses for all “round II regional haze pollutants” defined by Oregon as SO <sub>2</sub> , NO <sub>X</sub> , and PM <sub>10</sub> . Under 340-223-0120, ODEQ may adjust information in the four-factor analyses for consistency or adjust the four-factor analyses based on other information ODEQ determines to be accurate, adequate, and sufficient. ODEQ reviewed the four-factor analyses from the facilities and adjusted for consistency with basic factors such as interest rates, equipment lifetime, and using potential to emit (PSEL) levels instead of actual emissions in determining potential cost-effective controls.

The four-factor analyses submitted to ODEQ pursuant to 340-223-0120, with the exception of Owens-Brockway and Gilchrist Forest Products, indicated that additional NO <sub>X</sub> , PM <sub>10</sub> , and SO <sub>2</sub> controls were either technologically infeasible or not cost effective. Nevertheless, Oregon reviewed these analyses and determined that in some cases controls may be feasible and cost effective. Accordingly, in letters dated January 21, 2021, ODEQ notified facilities based on the information provided in the four-factor analyses submitted by the sources that additional controls may be reasonable at the cost effective $10,000 per ton reduction threshold. ODEQ provided preliminary determinations of the control measures that may be reasonable based on rough cost control analyses. Importantly, these preliminary determinations did not factor in site-specific feasibility or other source-specific considerations. Therefore, the January 21, 2021, letters invited the affected facilities to discuss ODEQ's preliminary determination and provide additional information as the basis for alternative compliance through a SAFO between the parties under OAR 340-223-0110(2). These SAFOs and permit conditions imposed the new controls, emission limits, and/or emission monitoring at 13 facilities discussed below.

**Boise Cascade Wood Products, LLC—Elgin Complex
                    —Order 31-0006 and Associated Permit Conditions 
                    156**

[^156] Permit conditions: 56. Monitoring Requirement, 56a.Emission Calculation, Table 6 (Emission Factors) for Boilers 1 and 2 for PM <sub>10</sub> , SO <sub>2</sub> , NO <sub>X</sub> , 59-61. General Monitoring Requirements, 62-65. General Recordkeeping Requirements, 66-70 Boiler NESHAP Recordkeeping Requirements, and 71-75 General Reporting Requirements.

• Establishing a PSEL for SO <sub>2</sub> effective July 31, 2022.

• Installation of a Continuous Emission Monitoring System (CEMS) on Boiler 1 and Boiler 2 to measure NO <sub>X</sub> emissions by September 31, 2022.

• Installation of combustion improvement project or projects designed to achieve emissions reductions of NO <sub>X</sub> from Boiler 1 and Boiler 2 by 15% by July 31, 2023.

**Biomass One, L.P.
                    —Order 15-0159**

• Installation of CEMS on the north and south boilers by July 31, 2022.

• NO <sub>X</sub> optimization plan within 180 days after installation of the NO <sub>X</sub> CEMS.

• If Permittee is able to finalize a new power purchase agreement (PPA), Permittee shall notify ODEQ in writing within 14 calendar days. Or, if no new PPA is signed, Permittee shall cease operation by January 1, 2027, and request cancellation of their Title V operating permit.

• If a new PPA is signed, then no later than 180 days after notifying ODEQ of the new PPA, the Permittee shall submit a complete application for installation of NO <sub>X</sub> reduction technology that includes SCR on the North Boiler and South Boiler or demonstrates SCR is technically infeasible or presents other unacceptable energy or non-air quality impact. If SCR is technically infeasible or presents such other unacceptable impacts, the Permittee will propose the best available, technically feasible, and achievable NO <sub>X</sub> reduction option for ODEQ's review and approval. ODEQ will notify Permittee and provide Permittee with a reasonable opportunity to comment before approving a NO <sub>X</sub> reduction option in response to Permittee's application.

**EVRAZ Inc.
                    —Order 26-1865**

• By December 31, 2024, install low NO <sub>X</sub> burners on the pre-heat portions of EU-10 Reheat Furnace with a designed NO <sub>X</sub> emission factor of 170 pounds per million cubic feet of natural gas.

• During 2025, the permittee shall conduct source testing to verify the NO <sub>X</sub> emission factor for the EU-10 reheat furnace. After consultation with the permittee, ODEQ will calculate the new potential to emit (PTE) from EU-10 reheat furnace using the new NO <sub>X</sub> emission factor and adjust the permittee's NO <sub>X</sub> PSEL in its permit to account for the revised PTE, either pursuant to OAR 340-218-0200(1)(a)(A), as applicable, or upon permit renewal.

**Georgia-Pacific—Toledo LLC
                    —Order 21-0005**

• By July 31, 2026, the permittee shall complete a NO <sub>X</sub> reduction project that includes the installation of low NO <sub>X</sub> burners, flue gas recirculation, and CEMS on the three boilers, EU-11, EU-13, and EU-18 in order to achieve an emissions rate no greater than 0.09 lb/MMBtu on a seven day rolling basis.

• Or, the permittee shall complete replacement of EU-11, EU-13, and EU-18 with new technology no later than July 3l, 2031. PSELs for the replacement shall be 889 tons per year of NO <sub>X</sub> , 437 tons per year of SO <sub>2</sub> , and 311 tons per year of PM <sub>10</sub> , or the PSELs of the replaced units, whichever is lower. Under this option, the permittee shall not operate EU-11, EU-13, and EU-18 after July 31, 2031.

**Georgia Pacific—Wauna Mill
                    —Order No. 04-0004, Amendment No. 04-004-A1**

• NO <sub>X</sub> PSEL reductions phased from 2022 to 2026.

• By December 31, 2024, the permittee shall replace the existing Yankee burner with a low NO <sub>X</sub> burner achieving less than or equal to 0.03 pounds per million British thermal unit (lb/MMBtu).

• For Paper Machine 6: TAD1 Burner and TAD2 Burner, and Paper Machine 7: TAD1 Burner and TAD 2 Burner, the permittee shall have a NO <sub>X</sub> emissions rate no greater than 0.06 lb/MMBtu for each emissions point and shall use this emission rate for calculating compliance with PSELs.

• By July 31, 2026, the permittee shall install low NO <sub>X</sub> burners, flue gas recirculation, and CEMS on the power boiler to achieve an emissions rate no greater than 0.09 lb/MMBtu on a seven day rolling basis.

**International Paper Company—Springfield Mill
                    —Order 208850 and Associated Permit Conditions 
                    157**

[^157] Permit conditions: 186-189: PSEL monitoring for PM <sub>10</sub> , NO <sub>X</sub> and SO <sub>2</sub> , 192: recordkeeping requirements, and 198: PSEL compliance reporting.

• Effective July 31, 2022, the permittee's combined assigned PSELs for the power boiler, package boiler, lime kilns and recovery furnace shall be 237 tons per year for SO <sub>2</sub> , 962 tons per year for NO <sub>X</sub> , and 177 tons per year for PM <sub>10</sub> , as a 12-month rolling average.

• On the effective date of the SAFO, the permittee agrees to a fuel restriction to use natural gas for the power boiler and package boiler, except that it may operate on ultra-low sulfur diesel for no more than 48 hours per year and when needed for natural gas curtailments.

• On the effective date of the SAFO, the permittee agrees to a fuel restriction to use natural gas and black liquor solids for the recovery furnace, except that it may operate on ultra-low sulfur diesel for no more than 48 hours per year and when needed for natural gas curtailments.

• On the effective date of the SAFO, the permittee agrees to a fuel restriction to use natural gas, product turpentine, and product methanol for the lime kilns, except that it may operate the lime kilns on ultra-low sulfur diesel for no more than 48 hours per year and when needed for natural gas curtailments.

• By December 31, 2022, the permittee shall install CEMS and measure the emissions of NO <sub>X</sub> from the power boiler.

• On and after January 31, 2025, International Paper shall meet the following emission limit: a 0.25 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average from the power boiler.

• On and after December 31, 2025, the assigned PSEL for the power boiler is: 179 tons per year for NO <sub>X</sub> , as a 12-month rolling average.

In Oregon's November 22, 2023 supplement to the regional haze SIP, [^158] ODEQ provided technical background information to demonstrate that the newly imposed conditions under Order 208850 at International Paper Company Springfield Mill for the second regional haze planning period provide more stringent emissions control than the prior emission limits and methods cited by the EPA in our determination that this source was not subject-to-BART in the first regional haze planning period. [^159]

[^158] Page 4.

[^159] 75 FR 12651, March 8, 2011, at page 12660.

**Owens-Brockway
                    —Order 26-1876 and Associated Permit Conditions 
                    160**

[^160] Permit conditions: 33. Monitor and Record: for PM <sub>10</sub> , SO <sub>2</sub> , and NO <sub>X</sub> , 34. General Testing Requirement, 35. EU4 Emission Factor Verification Testing Requirements: for PM <sub>10</sub> , NO <sub>X</sub> , SO <sub>2</sub> , 36-38. General Monitoring and Recordkeeping Requirements, 39-42. General Recordkeeping Requirements, 43-46. General Reporting Requirements, and 47-48. Semi-annual and Annual Reports.

• Permanent shutdown of Furnace A.

• PSEL limit for combined PM <sub>10</sub> + NO <sub>X</sub> + SO <sub>2</sub> = 274.95 tons per year which results in a Q/d = 4.99, consistent with OAR 340-223-0110(2)(b)(A).

**Willamette Falls Paper Company
                    —Order 03-2145 and Associated Permit Conditions 
                    161**

[^161] Permit conditions: 40a-40g. Monitoring Requirement: for PM <sub>10</sub> , NO <sub>X</sub> , SO <sub>2</sub> , 41. Visible Emission Monitoring Procedure, 42. Source Testing and Emission Factor Verification Procedure: for PM <sub>10</sub> , NO <sub>X</sub> , SO <sub>2</sub> , 43-45. General Monitoring Requirements, 46-49. General Recordkeeping Requirements, 50-53. General Reporting Requirements, and 54-56. Semi-annual and Annual Reports.

• Effective August 1, 2022, the permittee's PSELs shall be 20 tons per year for PM <sub>10</sub> , 240 tons per year for NO <sub>X</sub> , and 5 tons per year for SO <sub>2</sub> .

• On the effective date of the SAFO, the permittee agrees to a restriction that the only fuel the permittee may combust in Boiler 1, Boiler 2 and Boiler 3 is natural gas, except for ultra-low sulfur diesel for no more than 48 hours per year.

**Gas Transmission Northwest Compressor Station 13
                    —OAH CASE NO. 2021-ABC-4835 DEQ CASE NO. AQ/RH-HQ-2021-140 and Associated Permit Conditions 
                    162**

[^162] Permit conditions: 24-26. General Monitoring Requirements, 32-35. General Recordkeeping Requirements, 37-40. General Reporting Requirements, and 41-44. Semi-Annual and Annual Reports.

• By July 31, 2026, install and maintain SCR and an associated monitoring system on both Turbines 13C and 13D.

• Alternatively, by no later than July 31, 2031, replace Turbines 13C and 13D with new technology that meets the most recent permitting standards and requirements for new emission units (including but not limited to New Source Performance Standards) in place at the time of the respondent submitting a permit application for the project.

**Gilchrist Forest Products
                    —Permit 18-0005-TV-01, Addendum No. 1**

• Installation of an electrostatic precipitator on boilers B-1 and B-2.

• A PM <sub>10</sub> PSEL reduction from 172 tpy to 77 tpy.

**Northwest Pipeline LLC—Oregon City Compressor Station
                    —Order 03-2729, Amendment 03-2729-A1**

• Under the SAFO, the permittee agrees to replace two reciprocating internal combustion engines to meet the emission limits and requirements of the most recent New Source Performance Standard. No later than July 1, 2026, ODEQ and the permittee will meet to discuss what permitting needs are necessary for the replacement, with replacement complete no later than July 31, 2031.

**Cascade Pacific Pulp, LLC—Halsey Pulp Mill
                    —Order 22-3501-A2**

• By June 30, 2024, the permittee shall eliminate the use of #6 fuel oil.

• No later than July 31, 2031, replace power boiler #2 with a new emissions unit that will achieve a limit of 0.036 lbs NO <sub>X</sub> /MMBtu as a 30-day rolling average.

• Upon replacement of power boiler #2, limit emissions from power boiler #1 to no more than 27 tons of NO <sub>X</sub> per year.

**Roseburg Forest Products, Dillard
                    —Order 10-0025**

• By July 31, 2022, the permittee shall install CEMS to measure the emissions of NO <sub>X</sub> from Boiler 1, Boiler 2 and Boiler 6.

• From January 31, 2023, until June 30, 2025, the permittee shall meet the following emission limits: 0.30 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average at Boiler 1; 0.30 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average at Boiler 2; 0.28 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average at Boiler 6; Or average of emissions from boiler 1, boiler 2, and boiler 6 of 0.28 lb NO <sub>X</sub> /MMBtu (7-day rolling average).

• By January 31, 2024, the permittee shall notify ODEQ whether the permittee will comply with the emission limits below using boiler optimization or through installation of SNCR. If permittee determines SNCR is necessary to meet emission limits, SNCR shall be installed, permitted, and operational by June 30, 2025.

• On and after June 30, 2025, the permittee shall meet the following emission limits: 0.27 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average at Boiler 1; 0.26 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average at Boiler 2; 0.26 lb NO <sub>X</sub> /MMBtu on a 7-day rolling average at Boiler 6; or average of emissions from Boiler 1, Boiler 2, and Boiler 6 of 0.25 lb NO <sub>X</sub> /MMBtu (7-day rolling average).

The EPA notes that each of the controls and emission limits discussed above limit emissions of one or more of the “round II regional haze pollutants.” In most cases, Oregon determined that NO <sub>X</sub> was the dominant visibility-impairing pollutant from the sources and thus imposed additional NO <sub>X</sub> controls or submitted the enforceable emission limitations for existing NO <sub>X</sub> controls. For some emission units within the stationary sources discussed in the previous paragraphs, Oregon did not adopt additional pollutant-specific controls, primarily for PM <sub>10</sub> and SO <sub>2</sub> . Based on a review of the four-factor analyses, Oregon determined that these emission units either already employ existing effective controls or, by virtue of design, have insignificant emissions.

In particular, Oregon determined that PM <sub>10</sub> emissions for most of the relevant emission units have been and continue to be controlled by multiclones, electrostatic precipitators, baghouses, or other feasible technology that consistently achieves >90% control efficiency for PM <sub>10</sub> . As a general matter, the four-factor analyses indicated that PM <sub>10</sub> controls have been in place for many years to meet Federal NESHAP, NSPS, or Oregon SIP requirements and that these controls must remain in place to meet these continuing standards for the duration of the second planning period. [^163] Accordingly, Oregon determined that these existing effective controls were not necessary for reasonable progress for the second planning period.

[^163]*See, e.g.,* 115_18-0013Collins4FA.pdf at 3-4; 104_haze_BoiseCasecade-ElginFFA.pdf at 2-14; 107_haze-BoiseCascade-Medford-FFA.pdf; 110_haze-CascadePacificPulp-HalseyMill-FFA.pdf at 2-8, 3-5, 4-6-4-11, 3; 117_18-0014ColumbiaForestProducts4FA.pdf at 11.

In other cases, Oregon determined that the nature and mode of operation of particular sources yielded insignificant emissions. For example, at the Boise Cascade Wood Products, LLC's Elgin and Medford Mills the sulfur content of wood derived fuel is low, and the majority of the sulfur content is combined with the ash products of combustion. [^164] Thus, Oregon either did not select these emission units for four-factor analysis for a given pollutant or determined that the existing emission limits for a given pollutant were not necessary for reasonable progress. Therefore, Oregon focused primarily on NO <sub>X</sub> and SO <sub>2</sub> , with PM <sub>10</sub> analysis and limits when warranted. Accordingly, to the extent that Oregon did not submit the enforceable emission limitations for PM <sub>10</sub> or other pollutant controls for certain emission units within a given source selected for four-factor analysis the EPA proposes to determine that Oregon's selection of emission units to review under the four factors is consistent with the Regional Haze Rule and that the existing effective controls are not necessary for reasonable progress.

[^164] See 104_haze_BoiseCasecade-ElginFFA.pdf at 2-15; 107_haze-BoiseCascade-Medford-FFA.pdf at 2-4.

**Facilities for Which No Controls Were Cost-Effective**

ODEQ reviewed the four-factor analyses from the facilities and adjusted for consistency with basic factors such as using current prime rate (3.25%), 30-year lifetime, and calculation of cost effective controls using PSEL emissions limits rather than actual emissions. After initial review, ODEQ ruled out control devices for which the cost of control was greater than $10,000 per ton or provided an emissions reduction (using emissions at PSEL) of less than 20 tons per year. In letters sent August and September 2020, ODEQ notified 6 facilities with the determination that the agency did not find any controls deemed cost effective at the $10,000/ton threshold. [^165] These facilities were Pacific Wood Laminates, Inc., Swanson Group Mfg. L.L.C., Ochoco Lumber Company, Columbia Forest Products, Inc., Collins Products, L.L.C., and Woodgrain Millwork L.L.C.—Particleboard. In order to ensure no future impairment to visibility from these facilities, ODEQ submitted Title V permits for these facilities to incorporate into the SIP permitting conditions for these existing controls relevant to the regional haze program. The EPA reviewed these four-factor analyses, and we propose to find that ODEQ's determinations for these sources are reasonable and consistent with 40 CFR 51.308(f)(2)(i) and (iii).

[^165] The facility-submitted four-factor analyses and ODEQ response letters are included in the docket for this action.

**The EPA's Proposed Approval Oregon's Long-Term Strategy for Stationary Sources**

The EPA reviewed ODEQ's four-factor analyses, determinations of controls necessary for reasonable progress, and submitted SAFOs and permit conditions. Based on this review, the EPA proposes to determine that Oregon's long-term strategy meets the requirements of 40 CFR 51.308(f)(2)(i) through (iii). Oregon submitted numerous four-factor analyses and demonstrated that its determination of controls necessary for reasonable progress were an outgrowth of its consideration of the four statutory factors. Notably, Oregon's $10,000 cost per ton threshold is one of, if not the highest, cost thresholds established by any state specifically for evaluating controls for the regional haze program. Ultimately, Oregon imposed new, substantive controls at 13 facilities (covering over 36 emissions units) and established emissions limits at an additional 10 facilities with low actual emissions to ensure that future emissions do not rise above the screening threshold.

The EPA acknowledges that the final control measures imposed by the SAFOs and permits described in the preceding paragraphs in some cases differ from Oregon's preliminary control determinations contained in ODEQ's January 21, 2021, letters. We reviewed the four-factor analyses and Chapter 3.7 of Oregon's regional haze SIP, *Facility-Specific Findings and Results,* which contain a brief overview of the site-specific and feasibility concerns ODEQ considered in making final determinations, along with additional supporting information contained in the November 22, 2023, supplement.

Based on this review, the changes from preliminary to final control determinations appear reasonable and consistent with the Regional Haze Rule. Importantly, Oregon's iterative process to identify and adopt technically feasible, cost-effective controls reinforces that the State considered the four statutory factors to determine the controls necessary for reasonable progress.

Considering ODEQ's conservative screening methodology to use permitted emissions limits, the high $10,000 cost per ton reduction threshold Oregon used in reviewing the four-factor analyses submitted by the sources, the conservative methodology of evaluating controls using permitted emissions limits, the number of new emissions controls imposed specifically under the regional haze program, and the significant emissions reductions achieved through the SAFOs described in the previous paragraphs, we are proposing to determine that Oregon satisfied the requirement to determine the emission reduction measures that are necessary to make reasonable progress by considering the costs of compliance, the time necessary for compliance, the energy and non-air quality environmental impacts of compliance, and the remaining useful life of any potentially affected anthropogenic source of visibility impairment.

**c. Additional Long-Term Strategy Requirements**

The consultation requirements of 40 CFR 51.308(f)(2)(ii) provide that states must consult with other states that are reasonably anticipated to contribute to visibility impairment in a Class I area to develop coordinated emission management strategies containing the emission reductions measures that are necessary to make reasonable progress. Section 51.308(f)(2)(ii)(A) and (B) require states to consider the emission reduction measures identified by other states as necessary for reasonable progress and to include agreed upon measures in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what happens if states cannot agree on  what measures are necessary to make reasonable progress.

Oregon participated in and provided documentation of the WRAP intra- and inter-regional planning organization consultation processes in the submission. [^166] Oregon also had direct consultations with California, Idaho, Nevada, and Washington for sources where a Q/d analysis showed potential impacts on Oregon Class I areas or where Oregon sources may impact other states, as discussed in section IV.C of this preamble. The Oregon SIP submissions contain the list of out-of-state facilities potentially impacting Oregon Class I areas and a summary of the four-factor analysis process and the potential controls pursued by Idaho, Nevada, and Washington at the time of the consultation. [^167] During the state-to-state consultation and WRAP process, no other states identified measures for Oregon to consider. Therefore, we are proposing to determine that the Oregon regional haze plan satisfies 40 CFR 51.308(f)(2)(ii)(A) and (B). Oregon also satisfies 40 CFR 51.308(f)(2)(ii)(C) by having participated in the WRAP's consultation process and direct consultation with California, Idaho, Nevada, and Washington. No disagreements were raised by other states with respect to Oregon's planning efforts. We propose to determine that Oregon has satisfied the consultation requirements of 40 CFR 51.308(f)(2)(ii).

[^166] April 29, 2022 Oregon SIP submission, Chapter 6.2. Consultations with States.

[^167] April 29, 2022 Oregon SIP submission, Chapter 3.3 Impact of facilities in other states on Oregon Class 1 areas.

The documentation requirement of 40 CFR 51.308(f)(2)(iii) provides that states may meet their obligations to document the technical bases on which they are relying to determine the emission reduction measures that are necessary to make reasonable progress through a regional planning organization, as long as the process has been “approved by all State participants.” As explained above, Oregon chose to rely on WRAP technical information, modeling, and analysis to support development of its long-term strategy, as well as the State's own analyses. The WRAP technical analyses on which Oregon relied are listed in the State's SIP submissions and include source contribution assessments, information on each of the four factors and visibility modeling information for selected sources, and evaluations of emission reduction strategies based on the anticipated control measures. [^168] Oregon also provided supplemental information to demonstrate the technical bases and emission information on which it relied to determine the emission reductions measures that are necessary to make reasonable progress. Based on the documentation provided by the State, we propose to find that Oregon has satisfied the requirements of 40 CFR 51.308(f)(2)(iii).

[^168] April 29, 2022, Oregon SIP submission, Chapter 5.1 Reasonable progress goals for Class I areas.

Section 51.308(f)(2)(iii) also requires that the emissions information considered to determine the measures that are necessary to make reasonable progress include information on emissions for the most recent year for which the state has submitted triennial emissions data to the EPA (or a more recent year), with a 12-month exemption period for newly submitted data. Oregon's SIP submission included 2017 NEI emission data for regional haze forming pollutants. Based on Oregon's consideration and analysis of emissions data in their SIP submissions, the EPA proposes to find that Oregon has satisfied the emissions information requirement in 40 CFR 51.308(f)(2)(iii).

We also propose to find that Oregon reasonably considered the five additional factors in 40 CFR 51.308(f)(2)(iv) in developing its long-term strategy. Pursuant to 40 CFR51.308(f)(2)(iv)(A), Oregon detailed the existing and ongoing State and Federal emission control programs that contribute to emission reductions through 2028. The Oregon regional haze SIP highlights the State's aggressive programs for mobile sources, including Oregon's adoption of California rules for medium- and heavy-duty on-road vehicles, Low Emission Vehicle and ZEV standards for passenger vehicles, and a state clean fuels program. [^169] Many of these same measures, as well as other measures for the nonroad mobile source category, also mitigate the impacts of construction activities as required by 40 CFR 51.308(f)(2)(iv)(B). [^170]

[^169] April 29, 2022 Oregon SIP submission, Chapter 4.5 Measures to Mitigate Impacts of Construction Activities and Mobile Source Strategies.

[^170] Ibid.

Pursuant to 40 CFR 51.308(f)(2)(iv)(C), source retirements and replacement schedules are addressed in Chapter 4.4 *Necessary Emission Reduction Measures, On-going Air Pollution Control Programs and Source Retirement/Replacement* of Oregon's April 29, 2022, submission. The primary source retirement considered in developing the 2028 emission projections was permanent closure of the coal-fired power plant in Boardman, as required under the regional haze plan for the first implementation period.

In considering smoke management as required in 40 CFR 51.308(f)(2)(iv)(D), Oregon explained, in Chapter 4.6 *Smoke Management Practices and Programs and Area Source Strategies* that it addresses smoke management through its SIP-approved smoke management plan [^171] and open burning rules. [^172] Open burn rules limit all types of open burning within the State and require that, where open burning is allowed, it is conducted only after obtaining appropriate permits for burning in specific locations on approved dates. Oregon also has several existing measures that help improve visibility at Class I areas including SIP-approved residential woodstove restrictions. [^173]

[^171] 86 FR 27976, May 25, 2021.

[^172] 82 FR 47122, October 11, 2017.

[^173] OAR Division 262—Heat Smart Program for Residential Woodstoves and Other Solid Fuel Heating Devices.

Oregon considered the anticipated net effect of projected changes in emissions as required by 40 CFR 51.308(f)(2)(iv)(E) by discussing, in Chapter 2.5 *Source Apportionment of Visibility Impairment and Weighted Emission Potential* of its April 29, 2022, submission, the photochemical modeling for the 2018-2028 period it conducted in collaboration with the WRAP.

Because Oregon has reasonably considered each of the five additional factors the EPA proposes to find that Oregon has satisfied the requirements of 40 CFR 51.308(f)(2)(iv).

**F. Reasonable Progress Goals**

Section 51.308(f)(3) contains the requirements pertaining to reasonable progress goals for each Class I area. Because Oregon is host to Class I areas, it is subject to both 40 CFR 51.308(f)(3)(i) and, potentially, to (ii). Section 51.308(f)(3)(i) requires a state in which a Class I area is located to establish reasonable progress goals—one each for the most impaired and clearest days—reflecting the visibility conditions that will be achieved at the end of the implementation period as a result of the emission limitations, compliance schedules and other measures required under paragraph (f)(2) to be in states' long-term strategies, as well as implementation of other Clean Air Act requirements. The long-term strategies as reflected by the reasonable progress goals must provide for an improvement in visibility on the most impaired days relative to the baseline period and ensure no degradation on the clearest days relative to the baseline period. Section  51.308(f)(3)(ii) applies in circumstances in which a Class I area's reasonable progress goals for the most impaired days represents a slower rate of visibility improvement than the uniform rate of progress calculated under 40 CFR 51.308(f)(1)(vi). Under 40 CFR 51.308(f)(3)(ii)(A), if the state in which a Class I area is located establishes a reasonable progress goal for the most impaired days that provides for a slower rate of visibility improvement than the uniform rate of progress, the state must demonstrate that there are no additional emission reduction measures for anthropogenic sources or groups of sources in the state that would be reasonable to include in its long-term strategy. Section 51.308(f)(3)(ii)(B) requires that if a state contains sources that are reasonably anticipated to contribute to visibility impairment in a Class I area in *another* state, and the reasonable progress goal for the most impaired days in that Class I area is above the uniform rate of progress, the upwind state must provide the same demonstration.

Chapters 2.1 *Most Impaired Days* and 2.2 *Clearest Days* of Oregon's regional haze SIP summarize baseline visibility conditions ( *i.e.,* visibility conditions during the baseline period) for the most impaired and clearest days, as well as information on natural visibility conditions and the calculated URP in 2018 and 2028. Chapter 5.1 *Reasonable progress goals for Class I Areas* shows the 2028 RPGs for the most impaired days and clearest days. The 2028 RPG projections are based on WRAP modeling which represents regulations on the books as of 2020 plus stationary source controls recommended from ODEQ's review of the four-factor analyses submittals. The modeled 2028 RPGs for the most impaired days are presented in table 5 of this preamble, along with adjusted and unadjusted 2028 URP glidepaths as calculated by the EPA. [^174]

[^174] Availability of Modeling Data and Associated Technical Support Document for the EPA's Updated 2028 Visibility Air Quality Modeling, September 2019.

| Monitor ID | Class I area | Baseline | Current | WRAP 2028 RPGs | Unadjusted | EPA 2028 |
| --- | --- | --- | --- | --- | --- | --- |
| MOHO | Mt. Hood Wilderness Area | 12.10 | 9.27 | 8.50 | 9.90 | 10.71 |
| THSI | Mt. Jefferson, Mt. Washington, and Three Sisters Wilderness Areas | 12.80 | 11.28 | 10.86 | 10.60 | 11.62 |
| CRLA | Crater Lake National Park; Diamond Peak, Mountain Lakes, and Gearhart Mountain Wilderness Areas | 9.36 | 7.98 | 7.72 | 7.70 | 8.85 |
| KALM | Kalmiopsis Wilderness Area | 13.34 | 11.97 | 11.63 | 11.13 | 11.87 |
| STAR | Strawberry Mountain and Eagle Cap Wilderness Areas | 14.53 | 11.19 | 10.47 | 11.35 | 12.69 |
| HECA | Hells Canyon Wilderness Area | 16.51 | 12.33 | 11.66 | 12.53 | 13.93 |

The 2017 Regional Haze Rule included a provision that allows states to propose an adjustment to the glidepath to account for impacts from anthropogenic sources outside the U.S. if the adjustment has been developed through scientifically valid data and methods. The EPA's visibility guidance states “to calculate the proposed adjustment(s), the State must add the estimated impact(s) to the natural visibility condition and compare the baseline visibility condition for the most impaired days to the resulting sum.” In 2019, the EPA conducted modeling to assist states in the development of Regional Haze SIPs for the second implementation period. In particular, the modeling provided the EPA's first comprehensive estimate of international anthropogenic emissions contributions to visibility impairment at Class I areas. [^175] ODEQ chose not to adjust the glidepath to account for impacts from anthropogenic sources outside the U.S.

[^175] Availability of Modeling Data and Associated Technical Support Document for the EPA's Updated 2028 Visibility Air Quality Modeling, September 2019.

As noted in Chapter 2.3 *Emissions Inventory Analysis* of Oregon's regional haze SIP submission, the 2017 SO <sub>2</sub> inventory is dominated by PGE Boardman's coal-fired power plant in Morrow County. With the closing of the plant in October 2020, statewide SO <sub>2</sub> emissions declined by 62%. ODEQ further concludes that at some monitors, ammonium sulfate is a large contributor to regional haze formation, but that contribution seems to be dominated by international anthropogenic sources and is projected to decrease by 77% as new standards for international marine shipping fuels take effect in 2020. [^176] Therefore, even though Oregon declined to adjust the glidepath for international anthropogenic sources, such as marine shipping, we believe this is information relevant to our review. In particular, all IMPROVE stations for Class I areas in Oregon have modeled 2028 RPGs below the 2028 URP glidepath as adjusted for international anthropogenic contribution for the most impaired days. For the most impaired days, the 2028 RPGs also represent an improvement relative to both baseline visibility conditions and current visibility conditions. Similarly, for the clearest days, the 2028 RPGs also represent an improvement relative to both baseline visibility conditions and current visibility conditions, as shown in table 6 of this preamble.

[^176] April 29, 2022 Oregon SIP submission, Chapter 2.1 Most Impaired Days.

| Monitor ID | Class I area | Baseline | Current | WRAP 2028 RPGs |
| --- | --- | --- | --- | --- |
| MOHO | Mt. Hood Wilderness Area | 2.17 | 1.39 | 1.29 |
| THSI | Mt. Jefferson, Mt. Washington, and Three Sisters Wilderness Areas | 3.04 | 2.61 | 2.53 |
| CRLA | Crater Lake National Park; Diamond Peak, Mountain Lakes, and Gearhart Mountain Wilderness Areas | 1.69 | 1.05 | 0.98 |
| KALM | Kalmiopsis Wilderness Area | 6.27 | 5.90 | 5.84 |
| STAR | Strawberry Mountain and Eagle Cap Wilderness Areas | 2.17 | 1.39 | 1.29 |
| HECA | Hells Canyon Wilderness Area | 5.52 | 4.00 | 3.79 |

As noted in the RHR at 40 CFR 51.308(f)(3)(iii), the reasonable progress goals are not directly enforceable, but will be considered by the Administrator in evaluating the adequacy of the measures in the implementation plan in providing for reasonable progress towards achieving natural visibility conditions at specific Class I areas. Regardless of whether we use an adjusted or unadjusted URP glidepath to evaluate Oregon's 2028 RPGs for the most impaired days, the regulatory purpose of the RPGs has been fulfilled because visibility conditions for all IMPROVE stations have improved since the baseline period.

That said, because Oregon did not adjust the glidepath and because the 2028 RPGs for several Class I areas are above the unadjusted glidepath, the demonstration requirement under 40 CFR 51.308(f)(3)(ii)(A) is triggered. Oregon addressed this obligation in Chapter 5.2 *Glidepath policy choice* stating, “DEQ's policy decision to represent URP as an unadjusted glidepath has some effect on whether 2028 visibility projections fall slightly below or slightly above the glidepath (primarily at the central and southern Oregon IMPROVE sites), but DEQ did not base regulatory stationary source control decisions on the URP. DEQ based control decisions on the factors described in section 3 of this plan, including analyses based on the four statutory factors. As discussed in section III.D. of this preamble, visibility projections below the glidepath do not provide `safe harbor' for sources.

The EPA acknowledges Oregon's position. The IMPROVE monitoring stations in the Cascades (THSI and CRLA) and Kalmiopsis (KALM) that are projected to have 2028 RPGs at or above the unadjusted glidepath are the same IMPROVE monitoring stations that Oregon demonstrated are highly impacted by international marine shipping as described in section IV.E.a. of this preamble. These emissions are projected to decrease by 77% due to new standards for international marine shipping fuels which became effective in 2020. [^177] Also as described in section IV.E.a. of this preamble, statewide NO <sub>X</sub> emissions are primarily from mobile sources, at about 80% of the inventory. The Oregon regional haze SIP highlights the State's aggressive programs for mobile sources, including Oregon's adoption of California rules for medium- and heavy-duty on-road vehicles, Low Emission Vehicle and ZEV standards for passenger vehicles, and the State's clean fuels program, representing one of the most stringent mobile source programs allowed under the Federal Clean Air Act.

[^177] International Marine Organization. 2020. A Breath of Fresh Air. *https://wwwcdn.imo.org/localresources/en/MediaCentre/HotTopics/Documents/Sulphur%202020%20infographic%202%20page.pdf.*

Section 51.308(f)(3)(ii)(A) requires that the state provide an assessment of the number of years it would take to attain natural visibility conditions if visibility improvement were to continue at the rate of progress selected by the state as reasonable for the implementation period. Because these two source categories described in the prior paragraphs, mobile source standards and international marine shipping, are generally outside the control of the State, ODEQ did not directly address this requirement. However, the State made clear in Chapter 5.2 *Glidepath policy choice* that Oregon fully intends to achieve natural conditions consistent with the unadjusted URP glidepath. Thus, Oregon's regional haze SIP clearly indicates that the State's assessment of the number of years it would take to achieve natural visibility conditions remains unchanged from that predicted by the URP glidepath at THIS and CRLA. In support of this argument, ODEQ highlighted the new standards for international marine shipping fuels that will dramatically reduce regional haze precursors, as discussed above. We are proposing to determine that this is a reasonable assumption because the State RPGs in question are only marginally above the unadjusted 2028 URP glidepath and generally well below the 2028 adjusted URP glidepath calculated by the EPA to account for contribution outside the State's control, such as international marine shipping. See Table 5 of this preamble.

Given the dominance of these two emissions source categories on the overall inventory, it is highly unlikely that differences in the stationary source controls selected by Oregon would significantly impact the projected RPG modeling for these IMPROVE monitoring stations. Nevertheless, as described in section IV.E.b. of this preamble, considering ODEQ's conservative screening methodology to use permitted emissions limits, the high $10,000 cost per ton reduction threshold Oregon used in reviewing the four-factor analyses submitted by the sources, the conservative methodology of evaluating controls using permitted emissions limits, the number of new emissions controls imposed specifically under the regional haze program, and the significant emissions reductions achieved, we are proposing to determine that there are no additional emission reduction measures for anthropogenic sources or groups of sources in the State that may reasonably be anticipated to contribute to visibility impairment in the Class I area that would be reasonable to include in the long-term strategy and that Oregon has met the robust demonstration requirement under 40 CFR 51.308(f)(3)(ii)(A).

Under 40 CFR 51.308(f)(3)(ii)(B), a state that contains sources that are reasonably anticipated to contribute to visibility impairment in a Class I area in another state for which a demonstration by the other state is required under 40 CFR 51.308(f)(3)(ii)(B) must demonstrate that there are no additional emission reduction measures that would be reasonable to include in its long-term strategy. Oregon's SIP revision included the modeled WRAP 2028 visibility projections for Redwood National Park and Lava Beds National Monument in California, both of which have WRAP-  calculated 2028 RPGs slightly above the unadjusted 2028 URP glidepath. All other potentially affected Class I areas in Idaho (Hells Canyon Wilderness Area—HECA), and Washington (Mount Rainier National Park—MORA and Mount Adam Wilderness Area/Goat Rocks Wilderness Area—WHPA) had 2028 RPGs below the unadjusted 2028 URP glidepath. [^178] Oregon addressed these two California Class I areas with RPGs above the unadjusted glidepath using the same rationale as the demonstration for 40 CFR 51.308(f)(3)(ii)(A). [^179]

[^178] Although Nevada was included in Oregon's state to state consultation, Oregon's Q/d analysis showed greater potential impacts on California, Idaho, and Washington Class I areas. Therefore, Oregon's RPG analysis focused on those impacted Class I areas. See April 29, 2022, Oregon SIP submission, Table 3 3. Oregon facilities with potential visibility impacts on other states.

[^179] April 29, 2022 Oregon SIP submission, Chapter 5.2 Glidepath policy choice.

In reviewing Oregon's regional haze SIP submissions, we note that Oregon identified one facility, Roseburg Forest Products—Dillard, as potentially impacting Redwood National Park with a Q/d of 10.39 based on 2017 actual emissions. Oregon's regional haze SIP submissions include a four-factor analysis for the facility and enforceable controls to reduce NO <sub>X</sub> emissions. Specifically, under the SAFO, the facility was provided the option to meet emissions limits by optimizing the operation of the boilers. However, should the facility not meet these emissions limits, SNCR must be installed, permitted, and made operational by June 30, 2025. With respect to Lava Beds National Monument in California, ODEQ determined that two facilities in Oregon potentially impact this Class I area. These facilities are Klamath Cogeneration Project and Collins Products, L.L.C. Klamath Cogeneration Project had a PSEL Q/d=8.69 and an actual Q/d=3.66, potential impact on this Class I area. Collins Products, L.L.C. had a PSEL Q/d=5.48 and an actual Q/d=2.43, potential impact on this Class I area. As previously discussed regarding adequate existing measures, Klamath Cogeneration Project is already well controlled with existing SCR on all six combustion turbine units, as well as the recent addition of ultra-low NO <sub>X</sub> burners on two of the units. Lastly, Oregon included a four-factor analysis for Collins Products, L.L.C. in its regional haze SIP. Based on this analysis, Oregon determined that existing controls were necessary for reasonable progress and that additional controls were not cost effective. Therefore, Oregon submitted permit 18-0013-TV-01 to ensure these controls are Federally enforceable and permanent. While the EPA did not independently conduct our own four-factor analyses on these sources, we are proposing to determine, based on Oregon's application of a high cost-effectiveness threshold and the small Q/d based on actual emissions for two of the sources, that Oregon has satisfied the obligation under 40 CFR 51.308(f)(3)(ii)(B). We also note that Oregon conducted state-to-state consultation with California, Idaho, Nevada, Washington, and the WRAP states generally, and no disagreements under 40 CFR 51.308(f)(2)(ii)(C) were identified by California or any other state. The EPA proposes to determine that Oregon has satisfied the applicable requirements of 40 CFR 51.308(f)(3) relating to RPGs.

**G. Monitoring Strategy and Other Implementation Plan Requirements**

Section 51.308(f)(6) specifies that each comprehensive revision of a state's regional haze SIP must contain or provide for certain elements, including monitoring strategies, emissions inventories, and any reporting, recordkeeping and other measures needed to assess and report on visibility. A main requirement of this section is for states with Class I areas to submit monitoring strategies for measuring, characterizing, and reporting on visibility impairment. Compliance with this requirement may be met through participation in the Interagency Monitoring of Protected Visual Environments (IMPROVE) network.

Chapter 1.5.2 *Monitoring strategy* of Oregon's SIP submission states, “Oregon will continue to participate in the IMPROVE monitoring network to measure, characterize and report aerosol monitoring data for long-term reasonable progress tracking. DEQ commits a portion of Oregon's PM <sub>2.5</sub> EPA funding to support the IMPROVE network. DEQ deems the IMPROVE network representative of conditions in all of Oregon's Class 1 areas and would rely on the IMPROVE Steering Committee to advise states if conditions changed such that additional monitors were necessary.”

Section 51.308(f)(6)(i) requires SIPs to provide for the establishment of any additional monitoring sites or equipment needed to assess whether reasonable progress goals to address regional haze for all mandatory Class I Federal areas within the state are being achieved. Regional haze data for Oregon Class I areas are collected by the IMPROVE monitoring stations shown in table 1 of this preamble. The monitoring stations are primarily operated by the U.S. Forest Service, except for the CRLA1 IMPROVE monitoring station which is operated and maintained by the National Parks Service. As noted in ODEQ's monitoring strategy chapter, Oregon would rely on the IMPROVE Steering Committee to advise if conditions changed such that additional monitors were necessary.

Section 51.308(f)(6)(ii) requires SIPs to provide for procedures by which monitoring data and other information are used in determining the contribution of emissions from within the state to regional haze visibility impairment at mandatory Class I Federal areas both within and outside the state. Oregon relied on the WRAP source apportionment modeling and the weighted emission potential (WEP) analysis to help discern the degree to which different sectors affect visibility in each Class I area. The source apportionment and WEP analysis are based on data from WRAP's Technical Support System website [^180] for the Round 2 regional haze analysis. [^181] We note that § 51.308(f)(6)(iii) does not apply to Oregon, because it has Class I areas.

[^180]*http://views.cira.colostate.edu/tssv2/.*

[^181] April 29, 2022 Oregon SIP submission, Chapter 2.5 Source Apportionment of Visibility Impairment and Weighted Emission Potential.

Section 51.308(f)(6)(iv) requires the SIP to provide for the reporting of all visibility monitoring data to the Administrator at least annually for each Class I area in the state. As noted in the prior paragraphs, the IMPROVE monitoring stations in Oregon are operated and maintained by the U.S. Forest Service and the National Park Service. The monitoring strategy for Oregon relies upon the continued availability of the IMPROVE network. Oregon supports the continued operation of the IMPROVE network by committing a portion of Oregon's PM <sub>2.5</sub> EPA funding to support the IMPROVE network.

Section 51.308(f)(6)(v) requires SIPs to provide for a statewide inventory of emissions of pollutants that are reasonably anticipated to cause or contribute to visibility impairment, including emissions for the most recent year for which data are available and estimates of future projected emissions. It also requires a commitment to update the inventory periodically. Oregon provides for emissions inventories and estimates for future projected emissions by participating in the WRAP regional planning organization (RPO) and complying with the EPA's Air Emissions Reporting Rule (AERR). In 40 CFR part 51, subpart A, the AERR  requires states to submit updated emissions inventories for criteria pollutants to the EPA's Emissions Inventory System (EIS) every three years. The emission inventory data is used to develop the NEI, which provides for, among other things, a triennial state-wide inventory of pollutants that are reasonably anticipated to cause or contribute to visibility impairment.

Chapter 2.3. *Emissions Inventory Analysis* of Oregon's submissions include tables of NEI data. The source categories of the emissions inventories included are: (1) point sources; (2) nonpoint sources; (3) non-road mobile sources; and (4) on-road mobile sources. Oregon included NEI emissions inventories based on 2017, the most recent year for which data are available. Oregon observed that statewide NO <sub>X</sub> emissions are primarily from mobile sources, at about 80% of the inventory, with another 13% of the inventory coming from fuel combustion. The 2017 SO <sub>2</sub> inventory is largely overwhelmed by PGE Boardman's coal-fired power plant in Morrow County. With the closing of the coal-fired operations in October 2020, those SO <sub>2</sub> emissions have been eliminated, and the remainder of the emissions in the inventory come from fuel combustion and prescribed fires. For particulate matter, major source sectors include prescribed fire and agriculture, comprising 77% of the anthropogenic inventory.

Section 51.308(f)(6)(v) also requires states to include estimates of future projected emissions and include a commitment to update the inventory periodically. Oregon relied on the WRAP 2028 emissions projections for WRAP states. WRAP completed two 2028 projected emissions modeling cases—a 2028 base case that considers only on-the-books controls and a 2028 control case that considers implementation of the controls based on ODEQ's review of four-factor analyses submitted by the screened in sources. [^182]

[^182] April 29, 2022 Oregon SIP submission, Chapter 5.1 Reasonable progress goals for Class I Areas.

The EPA proposes to find that Oregon has met the requirements of 40 CFR 51.308(f)(6) as described in the prior paragraphs, including through its continued participation in the IMPROVE network and the WRAP RPO and its on-going compliance with the AERR, and that no further elements are necessary at this time for Oregon to assess and report on visibility pursuant to 40 CFR 51.308(f)(6)(vi).

**H. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals**

Section 51.308(f)(5) requires that periodic comprehensive revisions of states' regional haze plans also address the progress report requirements of 40 CFR 51.308(g)(1) through (5). The purpose of these requirements is to evaluate progress towards the applicable reasonable progress goals for each Class I area within the state and each Class I area outside the state that may be affected by emissions from within that state. Sections 51.308(g)(1) and (2) apply to all states and require a description of the status of implementation of all measures included in a state's first implementation period regional haze plan and a summary of the emission reductions achieved through implementation of those measures. Section 51.308(g)(3) applies only to states with Class I areas within their borders and requires such states to assess current visibility conditions, changes in visibility relative to baseline (2000-2004) visibility conditions, and changes in visibility conditions relative to the period addressed in the first implementation period progress report. Section 51.308(g)(4) applies to all states and requires an analysis tracking changes in emissions of pollutants contributing to visibility impairment from all sources and sectors since the period addressed by the first implementation period progress report. This provision further specifies the year or years through which the analysis must extend depending on the type of source and the platform through which its emission information is reported. Finally, 40 CFR 51.308(g)(5), which also applies to all states, requires an assessment of any significant changes in anthropogenic emissions within or outside the state have occurred since the period addressed by the first implementation period progress report, including whether such changes were anticipated and whether they have limited or impeded expected progress towards reducing emissions and improving visibility.

Oregon's submission describes the status of measures of the long-term strategy from the first implementation period. The most significant was the amendment of the PGE Boardman Title V permit to include conditions requiring BART control installation and to permanently cease burning coal in the main boiler by December 31, 2020. In Oregon's 2017 5-year progress report, ODEQ reported that in 2011, PGE Boardman installed low NO <sub>X</sub> burners with a modified over-fire air system and in 2014, BART SO <sub>2</sub> controls, consisting of a dry sorbent injection (DSI) system. PGE Boardman was meeting BART NO <sub>X</sub> and SO <sub>2</sub> emission limitations. A second BART SO <sub>2</sub> emission limit was required in 2018 and the coal-fired facility closed permanently by December 2020. Chapter 2.1.2 *Emission Reductions Achieved by SIP Measures* of Oregon's SIP submissions show the most recent 2017 NEI data for sources subject to control in the first implementation period. Notably, SO <sub>2</sub> emissions declined dramatically with the 2020 closure of the PGE Boardman coal-fired power plant. The EPA proposes to find that Oregon has met the requirements of 40 CFR 51.308(g)(1) and (2) because its SIP submissions describe the measures included in the long-term strategy from the first implementation period, as well as the status of their implementation and the emission reductions achieved through such implementation.

Oregon's SIP submissions included summaries of the visibility conditions and the trend of the 5-year averages through 2018 at Class I area in the State. [^183] As shown in table 2 of this preamble, the SIP submissions included the 5-year baseline (2000-2004) visibility conditions for the clearest and most impaired days. The SIP submissions also included the current 5-year status (2014-2018) for the clearest and most impaired days. The SIP submissions also illustrated in Figures 5.3 to 5.8 the visibility metrics levels at Oregon Class I areas, including the 5-year rolling average for the clearest and most impaired days. [^184] The EPA therefore proposes to find that Oregon has satisfied the requirements of 40 CFR 51.308(g)(3).

[^183] April 29, 2022 Oregon SIP submission, Chapters 2.1. Most Impaired Days and 2.2. Clearest Days.

[^184] April 29, 2022 Oregon SIP submission, Chapter 5 Uniform Rate of Progress.

Pursuant to § 51.308(g)(4), as part of the November 22, 2023 supplement to the submission, [^185] Oregon provided a summary of emissions of NO <sub>X</sub> , SO <sub>2</sub> , PM <sub>10</sub> , PM <sub>2.5</sub> , VOCs, and NH <sub>3</sub> from all sources and activities, including from point, nonpoint, non-road mobile, and on-road mobile sources, for the time period from 2002 to 2021 (the most recent air pollutant emissions trends data available in the NEI at the time). [^186] Oregon also included a detailed analysis of SO <sub>2</sub> , NO <sub>X</sub> , PM <sub>10</sub> emissions for 2017 in the April 29, 2022 submission.

[^185] Oregon RH Emission Trends.xlsx.

[^186]*https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data.*

The reductions achieved by Oregon emission control measures are seen in the emissions inventory. Based on  Oregon's SIP submissions, and the supplemental information in the “Oregon RH Emission Trends” spreadsheet included in the docket for this action, NO <sub>X</sub> emissions have continuously declined in Oregon from 2002 through 2021, especially in the point, nonroad, and onroad mobile sectors. NO <sub>X</sub> emissions are expected to continue to decrease as fleet turnover occurs and older more polluting vehicles and equipment are replaced by newer, cleaner ones. During that period, onroad sources contributed almost half of the emissions at 46%, followed by nonroad sources contributing 29%, and NEI point and nonpoint sources contributing 14%. Emissions of SO <sub>2</sub> have shown a significant decline in Oregon over the period 2002 to 2021, particularly in the point, and onroad and nonroad mobile sectors. NEI point and nonpoint emissions have declined 85%. Onroad SO <sub>2</sub> mobile source emissions have declined 96% and nonroad sources have declined 97%. These reductions are due in part to closure of the PGE Boardman coal-fired power plant, as well as low sulfur fuel regulations. PM <sub>10</sub> emissions steadily decreased in the point, nonpoint, onroad, and nonroad categories for the period from 2002 to 2021. NEI point and nonpoint PM <sub>10</sub> emissions declined 62%. Onroad mobile source emissions declined 29% and nonroad sources declined 68% for PM <sub>10</sub> . PM <sub>2.5</sub> emissions declined 49% for the period from 2002 to 2021. Onroad mobile source emissions declined 63% and nonroad sources declined 68% for PM <sub>2.5</sub> due to Federal engine standards. VOC emissions declined 65% for the period 2002 to 2021 in part due to Federal new engine standards for onroad and nonroad vehicles and equipment, the State low emission vehicle programs, and SIP-approved area source rules. Ammonia (NH <sub>3</sub> ) emissions declined 34% for the period 2002 to 2021, with onroad mobile source emissions declining 30% due to Federal engine standards.

The EPA is proposing to find that the requirements of 40 CFR 51.308(g)(4) are satisfied by providing emissions information for NO <sub>X</sub> , SO <sub>2</sub> , PM <sub>10</sub> , PM <sub>2.5</sub> , VOCs, and NH <sub>3</sub> broken down by type of source. The emissions data in the SIP submission [^187] and the supplemental trend information [^188] support the assessment that anthropogenic haze-causing pollutant emissions in Oregon have decreased during the reporting period and that changes in emissions have not limited or impeded progress in reducing pollutant emissions and improving visibility. The EPA is proposing to find that the requirements of 40 CFR 51.308(g)(5) are met.

[^187] April 29, 2022 Oregon SIP submission, Chapter 2.3. Emissions Inventory Analysis.

[^188] Oregon RH Emission Trends.xlsx.

**I. Requirements for State and Federal Land Manager Coordination**

Section 169A(d) of the Clean Air Act requires states to consult with Federal Land Managers (FLMs) before holding the public hearing on a proposed regional haze SIP, and to include a summary of the Federal Land Managers' conclusions and recommendations in the notice to the public. In addition, 40 CFR 51.308(i)(2)'s Federal Land Manager consultation provision requires a state to provide FLMs with an opportunity for consultation that is early enough in the state's policy analyses of its emission reduction obligation so that information and recommendations provided by the FLMs can meaningfully inform the state's decisions on its long-term strategy. If the consultation has taken place at least 120 days before a public hearing or public comment period, the opportunity for consultation will be deemed early enough, Regardless, the opportunity for consultation must be provided at least sixty days before a public hearing or public comment period at the state level. Section 51.308(i)(2) also provides two substantive topics on which FLMs must be provided an opportunity to discuss with states: assessment of visibility impairment in any Class I area and recommendations on the development and implementation of strategies to address visibility impairment. Section 51.308(i)(3) requires states, in developing their implementation plans, to include a description of how they addressed FLM comments.

Chapter 6.3.2 *Consultations with Federal Land Managers* of ODEQ's April 29, 2022, submission discusses Oregon's consultation and coordination with the FLMs. The FLMs and ODEQ are partners in the WRAP, and as partners, engaged early in inter-state coordination calls and WRAP technical support system development calls. ODEQ provided a draft of the regional haze plan to the U.S. Forest Service and National Park Service on May 5, 2021. Additionally, ODEQ met with the National Park Service on January 9, 2020, September 25, 2020, February 19, 2021, May 27, 2021, June 30, 2021, and July 15, 2021, to discuss progress and provide updates on the regional haze plan. On July 23, 2021, ODEQ made all requested files available to National Parks Service on a Google drive, including an updated summary spreadsheet of ODEQ's findings and tentative agreements with facilities about control installation or emission reduction. ODEQ also met with the U.S. Forest Service on August 21, 2020, February 24, 2021, and May 27, 2021. ODEQ received U.S. Forest Service written comments on June 23, 2021. ODEQ received comments from the National Park service in several communications between April 2 and July 15, 2021. ODEQ summarized the dates and topics of the National Park Service comments received in table 6-1 of the April 29, 2022, submission. Chapter 6.3.4 *Federal Land Manager Comments and DEQ Responses* contains the FLM consultation comments and ODEQ responses, which were provided to the public as part of the comment period on the draft SIP. We have determined that Oregon provided adequate opportunity for FLM consultation, consistent with 40 CFR 51.308(i)(3).

On August 27, 2021, Oregon provided public notice on the draft SIP submission and held a public hearing on October 27, 2021. ODEQ notified the public, interested parties, the Federal Land Managers, air quality contacts from other states and regions, and the EPA. [^189] ODEQ accepted written public comment on the proposed rulemaking until 4 p.m. on November 1, 2021, after granting a 30-day extension from the original end date for public comment. Similarly, as part of the November 22, 2023, supplement to the regional haze SIP, ODEQ provided the FLMs a 60-day consultation opportunity and included responses to the FLM's comments in the draft SIP supplement that went out for public comment on September 15, 2023.

[^189] See “019_5.1.1 GovDelivery.BulletinDetailReport.8.27.21” included in the docket for this action.

For the reasons stated in the prior paragraphs, the EPA proposes to find that Oregon has satisfied the requirements under 40 CFR 51.308(i) to consult with the Federal Land Managers on its regional haze SIP for the second implementation period.

**V. Proposed Action**

The EPA is proposing to approve the Oregon SIP revision submitted on April 29, 2022, as supplemented on November 22, 2023, as satisfying the regional haze requirements for the second implementation period contained in 40 CFR 51.308(f).

The EPA is proposing to approve and incorporate by reference in 40 CFR 52.1970(c), *Table 2—EPA Approved Oregon Administrative Rules (OAR)* the following updates to Division 223 *Regional Haze Rules,* state effective July 26, 2021:

• 340-223-0010 *Purpose,* for maintaining reasonable progress and other requirements associated with Oregon's implementation of the Federal Regional Haze Rule;

• 340-223-0020 *Definitions,* updating this section to account for revised program requirements between the first regional haze implementation period and the second implementation period;

• 340-223-0100 *Screening Methodology for Sources for Round II of Regional Haze,* establishing the criteria for selecting sources for review under the regional haze program;

• 340-223-0110 *Options for Compliance with Round II of Regional Haze,* establishing requirements for sources and compliance options under the regional haze program;

• 340-223-0120 *Four Factor Analysis,* establishing the requirements for assessing potential controls for reasonable progress under the regional haze program; and

• 340-223-0130 *Final Orders Ordering Compliance with Round II of Regional Haze,* establishing ODEQ's unilateral order authority and procedures for contested case hearings under the regional haze program.

We are proposing to remove from incorporation by reference in 40 CFR 52.1970(c), *Table 2—EPA Approved Oregon Administrative Rules (OAR)* the outdated provisions from the first regional haze implementation period contained in sections 340-223-0030, 340-223-0040, 340-223-0050, 340-223-0060, 340-223-0070, and 340-223-0080, state-effective December 10, 2010, because the site-specific requirements contained in those revoked sections are no longer relevant. Specifically, the Portland General Electric (PGE) coal-fired power plant in Boardman ceased operation on October 15, 2020, pursuant to the requirements of the regional haze plan for the first implementation period as described in section IV.E. of this preamble.

In addition to the regulatory provisions, the EPA is proposing to approve and incorporate by reference in 40 CFR 52.1970(d), *EPA Approved Oregon Source-Specific Requirements* the source-specific requirements in table 7 of this preamble as part of Oregon's long-term strategy for regional haze.

| Name of source | Permit or order number | State | Explanations |
| --- | --- | --- | --- |
| Ash Grove Cement Company | Permit No. 01-0029-TV-01 | 10/16/2020 | Permit conditions (3), (9) through (11), (14), (16) through (28), (42), (45) through (76), (84) through (97), (99), (100), and (102) only. |
| Biomass One, L.P | Order No | 8/9/2021 |  |
| Boise Cascade Wood Products, LLC—Elgin Complex | Order No. 31-0006 | 8/12/2021 |  |
| Boise Cascade Wood Products, LLC—Elgin Complex | Permit No. 31-0006-TV-01 | 12/5/2016 | Permit condition (56), (59) through (75), (77), and (78) only. |
| Boise Cascade Wood Products, LLC—Medford | Order No. 15-0004 | 8/9/2021 |  |
| Boise Cascade Wood Products, LLC—Medford | Permit No. 15-0004-TV-01 | 2/20/2020 | Permit conditions (71), (72), and (74) through (88) only. |
| Cascade Pacific Pulp, LLC—Halsey Pulp Mill | Order No. 22-3501-A2 | 8/25/2023 |  |
| Cascades Tissue Group: A Division of Cascades Holding US Inc | Order No. 05-1849 | 8/18/2021 |  |
| Cascades Tissue Group: A Division of Cascades Holding US Inc | Permit No. 05-1849-TV-01 | 04/6/2018 | Permit conditions (24), (25), (27), and (29) through (43) only. |
| Collins Products, L.L.C | Permit No. 18-0013-TV-01 | 1/26/2015 | Permit conditions (3), (14) through (16), (19) through (24), (34) through (42), (63) through (75), and (77) only. |
| Columbia Forest Products, Inc | Permit No. 18-0014-TV-01 | 9/26/2017 | Permit conditions (3), (8) through (20), (22), (23), (34) through (52), (58) through (66), (67—introductory paragraph), (67.a), (67.b.iii) through (67.b.v), and (68) through (70). |
| EVRAZ Inc | Order No. 26-1865 | 8/9/2021 |  |
| Gas Transmission Northwest LLC—Compressor Station 12 | Order No. 09-0084 | 8/9/2021 |  |
| Gas Transmission Northwest LLC—Compressor Station 12 | Permit No. 09-0084-TV-01 | 8/10/2017 | Permit conditions (32) through (34) and (37) through (50) only. |
| Gas Transmission Northwest LLC—Compressor Station 13 | Order No. 03-2729-A1 | 6/1/2022 | OAH CASE NO. 2021-ABC-04835; |
| Gas Transmission Northwest LLC—Compressor Station 13 | Permit No. 18-0096-TV-01 | 7/11/2018 | Permit conditions (24) through (26), (32) through (35), and (37) through (44) only. |
| Georgia-Pacific—Toledo LLC | Order No. 21-0005, Amendment No. 21-005-A1 | 12/5/2022 |  |
| Georgia Pacific—Wauna Mill | Order No. 04-0004, Amendment No. 04-004-A1 | 12/5/2022 |  |
| Gilchrist Forest Products | Permit No. 18-0005-TV-01 | 7/25/2023 | Permit conditions (4), (5), (9), (10), (12) through (19), (41) through (43), (45) through (59), and (61) only. |
| International Paper—Springfield | Order No. 208850 | 8/9/2021 |  |
| International Paper—Springfield | Permit No. 208850 | 10/4/2016 | Permit conditions (186) through (189), (192), and (198) only. |
| JELD-WEN | Permit No. 18-0006-TV-01 | 12/01/2021 | Permit conditions (55) through (77) and (80) through (87) only. |
| JELD-WEN | Permit No. 18-0006-TV-01, Addendum No. 1 | 8/11/2022 | Permit conditions 53 and 53b only. |
| Kingsford Manufacturing Company | Permit No. 204402, addendum No. 2 | 11/15/2021 | Permit conditions (71) through (73) and (75) through (91) only. |
| Klamath Energy LLC—Klamath Cogeneration | Permit No. 18-0003-TV-01 | 6/12/2017 | Permit conditions (10) through (16), (18), (24) through (28), (32) through (37), (39) through (49), (51), (52), and (54), and (56) only. |
| Klamath Energy LLC—Klamath Cogeneration | Permit No. 18-0003-TV-01, Addendum No. 1 | 12/8/2020 | Permit conditions (3.a), (3.b), (61.l), and (66.b.xii). |
| Northwest Pipeline LLC—Baker Compressor Station | Order No. 01-0038, amendment 01-0038-A1 | 2/1/2022 |  |
| Northwest Pipeline LLC—Baker Compressor Station | Permit No. 01-0038-TV-01 | 1/12/2017 | Permit conditions (27) through (30) and (32) through (43) only. |
| Northwest Pipeline LLC—Oregon City Compressor Station | Order No. 03-2729, amendment 03-2729-A1 | 2/1/2022 |  |
| Northwest Pipeline LLC—Oregon City Compressor Station | Permit No. 03-2729-TV-01 | 2/19/2013 | Permit conditions (7), (19), (25) through (27), (38), (41), (45), and (50) through (65). |
| Ochoco Lumber Company | Permit No. 12-0032-ST-01 | 6/25/2019 | Permit conditions (1.1) through (1.3), (1.6), (2.1) through (2.5), (4.1) through (4.4), and (5.1) through (6.2). |
| Owens-Brockway Glass Container Inc | Order No. 26-1876 | 8/9/2021 |  |
| Owens-Brockway Glass Container Inc | Permit No. 26-1876-TV-01 | 12/10/2019 | Permit conditions (33) through (48) only. |
| Pacific Wood Laminates, Inc | Permit No. 08-0003-TV-01 | 12/30/2019 | Permit conditions (3), (9), (10), (12) through (19), (26) through (41), (56) through (71), and (73) only. |
| PGE Beaver Plant/Port Westward I Plant | Order No. 05-2606 | 8/10/2021 |  |
| PGE Beaver Plant/Port Westward I Plant | Permit No. 05-2520 | 01/21/2009 | Permit conditions (62) through (66), (68) through (78), (79.a), (80) through (83), (85), (87), (88.a), (89.d), (89.f), and (89.i) only. |
| Roseburg Forest Products—Dillard | Order No. 10-0025 | 8/9/2021 |  |
| Roseburg Forest Products—Medford MDF | Permit No. 15-0073-TV-01 | 08/18/2022 | Permit conditions (44) through (46), (48) through (61), (63), and (64) only. |
| Roseburg Forest Products—Riddle Plywood | Permit No. 10-0078-TV-01 | 07/31/2019 | Permit conditions (65), (66), (68) through (81) only. |
| Swanson Group Mfg. LLC | Permit No. 10-0045-TV-01 | 06/12/2017 | Permit conditions (4), (10) through (24), (25—introductory paragraph), (25.a) through (25.c), (27) through (40), (50) through (64), and (66) only. |
| Timber Products Co. Limited Partnership | Permit No. 15-0025-TV-01 | 6/23/2022 | Permit conditions (70) through (72) and (74) through (90) only. |
| Willamette Falls Paper Company | Order No. 03-2145 | 8/9/2021 |  |
| Willamette Falls Paper Company | Permit No. 03-2145-TV-01 | 2/24/2016 | Permit conditions (40) through (55) only. |
| Woodgrain Millwork LLC—Particleboard | Permit No. 31-0002-TV-01 | 5/24/2021 | Permit conditions (3), (12) through (21), (22—introductory paragraph), (22.a), (22.e), (22.f), (23), (25) though (28), (30) through (35), (37), (39) through (41), (43), (44), (46), (48), (49), (51) through (72), (80) through (94), and (96) only. |

**VI. Incorporation by Reference**

In this document, the EPA is proposing to include regulatory text in an EPA final rule that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference the regulatory and source-specific provisions described in section V. of this preamble. The EPA has made, and will continue to make, these materials generally available through *https://www.regulations.gov* and at the EPA Region 10 Office (please contact the person identified in the *FOR FURTHER INFORMATION CONTACT* section of this preamble for more information).

The EPA is also proposing to remove from incorporation by reference the regulatory provisions described in section V. of this preamble.

**VII. Statutory and Executive Order Reviews**

Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. Accordingly, this action merely proposes to approve state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993) and 14094 (88 FR 21879, April 11, 2023);

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 *et seq.* );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 *et seq.* );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.

In addition, this proposed action, pertaining to the Oregon regional haze SIP submissions for the second planning period, would not be approved to apply on any Indian reservation land or in any other area where the EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rulemaking would not have Tribal implications and would not impose substantial direct costs on tribal governments or preempt Tribal law as  specified by Executive Order 13175 (65 FR 67249, November 9, 2000). Consistent with EPA policy, the EPA provided a consultation opportunity to Tribes located in Oregon, in letters dated May 4, 2022, included in the docket for this action.

Executive Order 12898 (Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations, 59 FR 7629, February 16, 1994) directs Federal agencies to identify and address “disproportionately high and adverse human health or environmental effects” of their actions on minority populations and low-income populations to the greatest extent practicable and permitted by law. The EPA defines environmental justice (EJ) as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.” The EPA further defines the term fair treatment to mean that “no group of people should bear a disproportionate burden of environmental harms and risks, including those resulting from the negative environmental consequences of industrial, governmental, and commercial operations or programs and policies.” The Oregon Department of Environmental Quality did evaluate environmental justice considerations as part of its SIP submittal; the CAA and applicable implementing regulations neither prohibit nor require such an evaluation. The EPA did not perform an EJ analysis and did not consider EJ in this action. Consideration of EJ is not required as part of this action, and there is no information in the record inconsistent with the stated goal of Executive Order 12898 of achieving environmental justice for people of color, low-income populations, and Indigenous peoples.

**List of Subjects in 40 CFR Part 52**

Environmental protection, Air pollution control, Incorporation by reference, Intergovernmental relations, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur oxides, Volatile organic compounds.

**Authority:**

42 U.S.C. 7401 *et seq.*

Dated: February 14, 2024.

Casey Sixkiller,

Regional Administrator, Region 10.