ENVIRONMENT AL PROTECTION AGENCY 

40 CFR Part 52 

[EPA-RIO-OAR-2010-1072, FRLApproval and Promulgation of Implementation Plans; State of Idaho; Regional Haze State 

Implementation Plan and Interstate Transport Plan 

AGENCY: Environmental Protection Agency (EPA) 

ACTION: Proposed rule. 

SUMMARY: EPA is proposing to approve a State Implementation Plan (SIP) revision 

submitted by the State of Idaho on October 25, 2010, as meeting the requirements of Clean Air 

Act (CAA) section llO(a)(2)(D)(i)(II) as it applies to visibility for the 1997 8-hour ozone and 

1997 particulate matter (PM2.5) National Ambient Air Quality Standards (NAAQS). EPA is 

also proposing to approve a portion ofthe revision as meeting certain requirements ofthe 

regional haze program, including the requirements for best available retrofit technology (BART). 

DATES: Written comments must be received at the address below on or before [insert date 30 

days from the date of publication in the Federal Register] 

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-RIO-OAR-201O-1072 

by one ofthe following methods: 
• www.regulations.gov. Follow the on-line instructions for submitting comments. 

• E-mail: RIO-Public Comments@epa.gov· Mail: Steve Body, EPA Region 10, Suite 

900, Office of Air, Waste and Toxics, 1200 Sixth Avenue, Seattle, WA 98101 

• Hand Delivery: EPA Region 10, 1200 Sixth Avenue, Suite 900, Seattle, W A 98101. 

Attention: Steve Body, Office of Air, Waste and Toxics, AWT-I07. Such deliveries are 

only accepted during normal hours of operation, and special arrangements should be 

made for deliveries ofboxed information. 

Instructions: Direct your comments to Docket 10 No. EPA-R 1 0-OAR-201 0-1 072. EP Ns policy 

is that all comments received will be included in the public docket without change and may be 

made available online at www.regulations.gov, including any personal information provided, 

unless the comment includes information claimed to be Confidential Business Information (CBI) 

or other information whose disclosure is restricted by statute. Do not submit information that you 

consider to be CBI or otherwise protected through www.regulations.gov or e-mail. The 

www.regulations.gov Web site is an "anonymous access" system, which means EPA will not 

know your identity or contact information unless you provide it in the body of your comment. If 

you send an e-mail comment directly to EPA, without going through www.regulations.gov, your 

e-mail address will be automatically captured and included as part of the comment that is placed 

in the public docket and made available on the Internet. If you submit an electronic comment, 

EP A recommends that you include your name and other contact information in the body of your 

comment and wit~ any disk or CD-ROM you submit. If EPA cannot read your comment due to 

technical difficulties and cannot contact you for clarification, EPA may not be able to consider 

your comment. Electronic files should avoid the use ofspecial characters, any form of 

encryption, and be free of any defects or viruses. 

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Docket: All documents in the docket are listed in the www.regulations.gov index. 

Although listed in the index, some information is not publicly available (e.g., CBI or other 

information whose disclosure is restricted by statute). Certain other material, such as copyrighted 

material, will be publicly available only in hard copy form. Publicly available docket materials 

are available either electronically at www.regulations.gov or in hard copy at the Office ofAir, 

Waste and Toxics, EPA Region 10, 1200 Sixth Avenue, Seattle, W A 98101. EPA requests that if 

at all possible, you contact the individual listed in the 

FOR FURTHER INFORMATION CONTACT: Steve Body at telephone number (206) 553­

0782, body.steve@epa.gov, or the above EPA, Region 10 address. 

SUPPLEMENTARY INFORMATION: Throughout this document whenever "we," "us," or 

"our" is used, we mean the EPA. Information is organized as follows: 

Table of Contents 

I. Background for EPA's Proposed Action 

A. Definition of Regional Haze 

B. Regional Haze Rules and Regulations 

C. Roles ofAgencies in Addressing Regional Haze 

D. Interstate Transport for Visibility 

II. Requirements for the Regional Haze SIP 

A. The CAA and the Regional Haze Rule 

B. Determination ofBaseline, Natural, and Current Visibility Conditions 

C. Consultation with States and Federal Land Managers 

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D. Best Available Retrofit Technology 

III. EPA's Analysis of the Idaho Regional Haze SIP 

A. Affected Class I Areas 

B. Baseline and Natural Conditions 

C. Idaho Emissions Inventories 

D. Sources of Visibility Impairment in Idaho Class I Areas 

E. Best Available Retrofit Technology 

F. TASCa BART Analysis 

O. Monsanto/P4 BART Analysis 

H. Improvement in Visibility from BART at TASCa, Nampa and Monsanto/P4 

IV. EPA's Analysis of Whether Regional Haze SIP Submittal Meets Interstate Transport 

Requirements 

V. What Action is EPA Proposing? VI. Scope of Action 

VII. Statutory and Executive Order Reviews 

I. Background for EPA's Proposed Action 

In the CAA Amendments of 1977, Congress established a program to protect and 

improve visibility in the national parks and wilderness areas. See CAA section 169(A). 

Congress amended the visibility provisions in the CAA in 1990 to focus attention on the problem 

ofregional haze. See CAA section 169(B). EPA promulgated regulations in 1999 to implement 

sections 169 A and 169B ofthe Act. These regulations require states to develop and implement 

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plans to ensure reasonable progress toward improving visibility in mandatory Class I Federal 

areas

l (Class I areas). 64 FR 35714 (July 1, 1999); see also 70 FR 39104 (July 6, 2005) and 71 

FR 60612 (October 13,2006). 

In this action, EPA is proposing to approve certain provisions ofIdaho's Regional Haze 

SIP submission addressing the requirements for best available retrofit technology (BART), the 

calculation of baseline and natural visibility conditions, and the statewide inventory of visibilityimpairing pollutants. EPA is also proposing to approve the provisions of Idaho's SIP submittal 

addressing BART as meeting Idaho's obligations under section 11O(a)(2)(D)(i)(I) of the Act for 

visibility. EPA is not taking action today on those provisions of the Regional Haze SIP submittal 

related to reasonable progress goals and the long term strategy. 

A. Definition of Regional Haze 

Regional haze is impairment of visual range or colorization caused by emission of air 

pollution produced by numerous sources and activities, located across a broad regional area. The 

sources include but are not limited to, major and minor stationary sources, mobile sources, and 

area sources including non-anthropogenic sources. Visibility impairment is primarily caused by 

IAreas designated as mandatory Class I Federal areas consist of national parks exceeding 6000 acres, wilderness 

areas and national memorial parks exceeding 5000 acres, and all international parks that were in existence on 

August 7, 1977. 42 U.S.C. 7472(a). In accordance with section 169A of the CAA, EPA, in consultation with the 

Department ofInterior, promulgated a list of 156 areas where visibility is identified as an important value. 44 FR 

69122 (November 30, 1979). The extent of a mandatory Class I area includes subsequent changes in boundaries, 

such as park expansions. 42 U.S.C. 7472(a). Although states and tribes may designate as Class I additional areas 

which they consider to have visibility as an important value, the requirements of the visibility program set forth in 

section 169A of the CAA apply only to "mandatory Class I Federal areas." Each mandatory Class I Federal area is 

the responsibility of a "Federal Land Manager." 42 U.S.C. 7602(i). When we use the term "Class I area" in this 

action, we mean a "mandatory Class I Federal area." 

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fine particulate matter (PM2.5) or secondary aerosol formed in the atmosphere from precursor 

gasses (e.g., sulfur dioxide, nitrogen oxides, and in some cases, ammonia and volatile organic 

compounds). Atmospheric fine particulate reduces clarity, color, and visual range of visual 

scenes. Visibility reducing fine particulate is primarily composed ofsulfate, nitrate, organic 

carbon compounds, elemental carbon, and soil dust, and impairs visibility by scattering and 

absorbing light. Fine particulate can also cause serious health effects and mortality in humans, 

and contributes to environmental effects such as acid deposition and eutrophication.2 

Data from the existing visibility monitoring network, the "Interagency Monitoring of 

Protected Visual Environments" (IMPROVE) monitoring network, show that visibility 

impairment caused by air pollution occurs virtually all the time at most national parks and 

wilderness areas. Average visual range in many Class I areas in the Western United States is 

100-150 kilometers, or about one-half to two-thirds the visual range that would exist without 

manmade air pollution.3 Visibility impairment also varies day-to-day and by season depending 

on variation in meteorology and emission rates. 

B. Regional Haze Rules and Regulations 

In section 169A ofthe 1977 CAA Amendments, Congress created a program for 

protecting visibility in the nation's national parks and wilderness areas. This section of the CAA 

establishes as a national goal the "prevention of any future, and the remedying of any existing, 

2 See 64 FR at 35715. 

3Id. 

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impainnent of visibility in Class I areas which impainnent results from manmade air pollution." 

CAA section 169A(a)(I). On December 2, 1980, EPA promulgated regulations to address 

visibility impainnent in Class I areas that is "reasonably attributable" to a single source or small 

group ofsources, i.e., "reasonably attributable visibility impainnent". 45 FR 80084. These 

regulations represented the first phase in addressing visibility impainnent. EPA deferred action 

on regional haze that emanates from a variety of sources until monitoring, modeling and 

scientific knowledge about the relationships between pollutants and visibility impainnent were 

improved. 

Congress added section 169B to the CAA in 1990 to address regional haze issues. EPA 

promulgated a rule to address regional haze on July 1, 1999 (64 FR 35713)(the RHR). The RHR 

revised the existing visibility regulations to integrate into the regulation provisions addressing 

regional haze impainnent and established a comprehensive visibility protection proh,Jfam for 

Class I areas. The requirements for regional haze, found at 40 CFR 51.308 and 51.309, are 

included in EPA's visibility protection regulations at 40 CFR 51.300-309. Some ofthe main 

elements ofthe regional haze requirements are summarized in section III ofthis rulemaking. 

The requirement to submit a regional haze SIP applies to all 50 states, the District ofColumbia 

and the Virgin Islands.4 40 CFR 51.308(b) requires states to submit the first implementation 

plan addressing regional haze visibility impainnent no later than December 17,2007. 

C. Roles of Agencies in Addressing Regional Haze 

4Albuquerque/Bemalillo County in New Mexico must also submit a regional haze SIP to completely satisfy the 

requirements of section 11O(a)(2)(D) of the CAA for the entire State of New Mexico under the New Mexico Air 

Quality Control Act (section 74-2-4). 

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Successful implementation of the regional haze program will require long-tenn regional 

coordination among states, tribal governments and various Federal agencies. As noted above, 

pollution affecting the air quality in Class I areas can be transported over long distances, even 

hundreds of kilometers. Therefore, to effectively address the problem of visibility impainnent in 

Class I areas, states need to develop strategies in coordination with one another, taking into 

account the effect of emissions from one jurisdiction on the air quality in another. 

Because the pollutants that lead to regional haze impainnent can originate from across 

state lines, EPA has encouraged the States and Tribes to address visibility impainnent from a 

regional perspective. Five regional planning organizations (RPOs) were created nationally to 

address regional haze and related issues. One ofthe main objectives of the RPOs is to develop 

and analyze data and conduct pollutant transport modeling to assist the States or Tribes in 

developing their regional haze plans. 

The Western Regional Air Partnership (WRAP), one ofthe five 

RPOs nationally, is a voluntary partnership of State, Tribal, Federal, and local air agencies 

dealing with air quality in the West. WRAP member States include: Alaska, Arizona, California, 

Colorado, Idaho, Montana, New Mexico, North Dakota, Oregon, South Dakota, Utah, 

Washington, and Wyoming. WRAP Tribal members include Campo Band of Kumeyaay 

Indians, Confederated Salish and Kootenai Tribes, Cortina Indian Rancheria, Hopi Tribe, 

Hualapai Nation ofthe Grand Canyon, Native Village ofShungnak, Nez Perce Tribe, Northern 

Cheyenne Tribe, Pueblo of Acoma, Pueblo of San Felipe, and Shoshone-Bannock Tribes of Fort 

Hall. 

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D. Interstate Transport for Visibility 

On July 18, 1997, EPA promulgated new NAAQS for 8-hour ozone and for PM2.S. 62 

FR 386S2. Section 110(a)(1) of the CAA requires states to submit a plan to address certain 

requirements for a new or revised NAAQS within three years after promulgation of such 

standards, or within such shorter time as EPA may prescribe. Section 11 O(a)(2) of the CAA lists 

the elements that such new plan submissions must address, as applicable, including section 

110(a)(2)(D)(i), which pertains to the interstate transport of certain emissions. 

On April 2S, 200S, EPA published a "Finding ofFailure to Submit SIPs for Interstate 

Transport for the 8-hour Ozone and PM2.S NAAQS." 70 FR 21147. This included a finding 

that Idaho and other states had failed to submit SIPs to address interstate transport of emissions 

affecting visibility and started a 2-year clock for the promulgation of a Federal Implementation 

Plan (FIP) by EPA, unless the state made a submission to meet the requirements ofsection 

11O(a)(2)(D)(i) and EPA approves such submission. Id. 

On August IS, 2006, EPA issued guidance on this topic entitled "Guidance for State 

Implementation Plan (SIP) Submissions to Meet Current Outstanding Obligations Under section 

11O(a)(2)(D)(i) for the 8-Hour Ozone and PM2.S National Ambient Air Quality Standards" 

(2006 Guidance). We developed the 2006 Guidance to make recommendations to states for 

making submissions to meet the requirements of section 11 O(a)(2)(D)(i) for the 1997 8-hour 

ozone standards and the 1997 PM2.S standards. 

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As identified in the 2006 Guidance, the "good neighbor" provisions in section 

11O(a)(2)(D)(i) ofthe CAA require each state to have a SIP that prohibits emissions that 

adversely affect other states in ways contemplated in the statute. Section 11 0(a)(2)(D)(i) 

contains four distinct requirements related to the impacts ofinterstate transport. The SIP must 

prevent sources in the state from emitting pollutants in amounts which will: (1) contribute 

significantly to nonattainment ofthe NAAQS in other states; (2) interfere with maintenance of 

the NAAQS in other states; (3) interfere with provisions to prevent significant deterioration of air 

quality in other states; or (4) interfere with efforts to protect visibility in other states. 

With respect to establishing that emissions from sources in the state would not interfere 

with measures in other states to protect visibility, the 2006 Guidance recommended that states 

make a submission indicating that it was premature, at that time, to detemline whether there 

would be any interference with measures in the applicable SIP for another state designed to 

"protect visibility" until the submission and approval ofregional haze SIPs. Regional haze SIPs 

were required to be submitted by December 17,2007. See 74 FR 2392. At this later point in 

time, however, EPA believes it is now necessary to evaluate such 11 0(a)(2)(D)(i) submissions 

from a state to ensure that the existing SIP, or the SIP as modified by the submission, contains 

adequate provisions to prevent interference with the visibility programs of other states, such as 

for consistency with the assumptions for controls relied upon by other states in establishing 

reasonable progress goals to address regional haze. 

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The regional haze program, as reflected in the RHR, recognizes the importance of addressing 

the long-range transport of pollutants for visibility and encourages states to work together to 

develop plans to address haze. The regulations explicitly require each state to address its "share" 

ofthe emission reductions needed to meet the reasonable progress goals for neighboring Class I 

areas. States working together through a regional planning process, are required to address an 

agreed upon share oftheir contribution to visibility impairment in the Class I areas oftheir 

neighbors. 40 CFR SI.308( d)(3 )(ii). Given these requirements, we anticipate that regional haze 

SIPs will contain measures that will achieve these emissions reductions, and that these measures 

will meet the requirements of section 11 0(a)(2)(D)(i). 

As a result ofthe regional planning efforts in the West, all states in the WRAP region 

contributed information to a Technical Support System (TSS) which provides an analysis ofthe 

causes of haze, and the levels of contribution from all sources within each state to the visibility 

degradation of each Class I area. The WRAP States consulted in the development ofreasonable 

progress goals, using the products ofthis technical consultation process to co-develop their 

reasonable progress goals for the Western Class I areas. The modeling done by the WRAP relied 

on assumptions regarding emissions over the relevant planning period and embedded in these 

assumptions were anticipated emissions reductions in each ofthe States in the WRAP, including 

reductions from BART and other measures to be adopted as part ofthe State's long term strategy 

for addressing regional haze. The reasonable progress goals in the draft and final regional haze 

SIPs that have now been prepared by States in the West accordingly are based, in part, on the 

emissions reductions from nearby States that were agreed on through the WRAP process. 

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Idaho submitted a Regional Haze SIP on October 25,2010, to address the requirements of 

the RHR and the good neighbor provisions ofsection 11 O(a)(2)(D)(i) regarding visibility for the 

1997 8-hour ozone NAAQS and the 1997 PM2.5 NAAQS. EPA has reviewed the submittal and 

concluded at this time to propose to take action on only certain elements of Idaho's Regional 

Haze SIP. EPA is required at this time, to propose to take action either to approve Idaho's SIP 

submittal, or otherwise to take action to meet the requirements of section 11O(a)(2)(D)(i)(II) 

regarding visibility.5 EPA is proposing to find that certain elements ofIdaho's Regional Haze 

SIP submittal meet these requirements. In particular, as explained in section IV ofthis action, 

EPA is proposing to find that the BART measures in Idaho's Regional Haze SIP submittal, 

which EPA is proposing to approve in this action, will also mean that the Idaho SIP meets the 

requirements ofsection llO(a)(2)(D)(i)(II) regarding visibility for the 1997 8-hour ozone and 

1997 PM2.5 NAAQS. 

II. Requirements for Regional Haze SIPs 

A. The CAA and the Regional Haze Rule 

Regional haze SIPs must assure reasonable progress towards the national goal of 

achieving natural visibility conditions in Class I areas. Section 169 A ofthe CAA and EPA's 

implementing regulations require states to establish long-term strategies for making reasonable 

progress toward meeting this goal. Implementation plans must also give specific attention to 

certain stationary sources that were in existence on August 7, 1977, but were not in operation 

before August 7, 1962, and require these sources, where appropriate, to install BART controls 

5 Wildearth Guardians v. Jackson, Case No. 4:09-CV-02453-CW (N.D. Calif).. 

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for the purpose of eliminating or reducing visibility impairment. The specific regional haze SIP 

requirements are discussed in further detail below. 

B. Determination of Baseline, Natural, and Current Visibility Conditions 

The RHR establishes the deciview (dv) as the principal metric for measuring visibility. 

This visibility metric expresses uniform changes in haziness in terms of common increments 

across the entire range ofvisibility conditions, from pristine to extremely hazy conditions. 

Visibility is determined by measuring the visual range (or deciview), which is the greatest 

distance, in kilometers or miles, at which a dark object can be viewed against the sky. The 

deciview is a useful measure for tracking progress in improving visibility, because each deciview 

change is an equal incremental change in visibility perceived by the human eye. Most people 

can detect a change in visibility at one deciview.6 

The deciview is used in expressing reasonable progress goals (which are interim visibility 

goals towards meeting the national visibility goal), defining baseline, current, and natural 

conditions, and tracking changes in visibility. The regional haze SIPs must contain measures 

that ensure "reasonable progress" toward the national goal of preventing and remedying visibility 

impairment in Class I areas caused by manmade air pollution by reducing anthropogenic 

emissions that cause regional haze. The national goal is a return to natural conditions, i.e., 

manmade sources of air pollution would no longer impair visibility in Class I areas. 

6The preamble to the RHR provides additional details about the deciview. 64 FR 35714, 35725 (July 1, 1999). 

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To track changes in visibility over time at each of the 156 Class I areas covered by the 

visibility program (40 CFR 81.401-437), and as part of the process for determining reasonable 

progress, states must calculate the degree of existing visibility impairment at each Class I area at 

the time of each regional haze SIP submittal and periodically review progress every five years 

midway through each 10-year implementation period. To do this, the RHR requires states to 

determine the degree ofimpairment (in deciviews) for the average of the 20% least impaired 

(''best'') and 20% most impaired ("worst") visibility days over a specified time period at each of 

their Class I areas. In addition, states must also develop an estimate of natural visibility 

conditions for the purpose of comparing progress toward the national goaL Natural visibility is 

determined by estimating the natural concentrations of pollutants that cause visibility impairment 

and then calculating total light extinction based on those estimates. EPA has provided guidance 

to states regarding how to calculate baseline, natural and current visibility conditions in 

documents titled, EPA's Guidance for Estimating Natural Visibility Conditions Under the 

Regional Haze Rule, September 2003, (EP A-454/B-03-005 located at 

http://www .epa.gov/ttncaaa litlImemorandairh envcurhr gd.pdf), (hereinafter referred to as 

"EPA's 2003 Natural Visibility Guidance"), and Guidancefor Tracking Progress Under the 

Regional Haze Rule (EP A-454/B-03-004 September 2003 located at 

http://www.epa.gov/ttncaaalltllmemoranda/rh tpurhr gd.pdf), (hereinafter referred to as 

"EPA's 2003 Tracking Progress Guidance"). 

For the first regional haze SIPs that were due by December 17, 2007, "baseline visibility 

conditions" were the starting points for assessing "current" visibility impairment. Baseline 

visibility conditions represent the degree ofvisibility impairment for the 20% least impaired days 

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and 20% most impaired days for each calendar year from 2000 to 2004. Using monitoring data 

for 2000 through 2004, states are required to calculate the average degree ofvisibility 

impairment for each Class I area, based on the average of annual values over the five-year 

period. The comparison ofinitial baseline visibility conditions to natural visibility conditions 

indicates the amount ofimprovement necessary to attain natural visibility, while the future 

comparison of baseline conditions to the then current conditions will indicate the amount of 

progress made. In general, the 2000 - 2004 baseline time period is considered the time from 

which improvement in visibility is measured. 

C. Consultation with States and Federal Land Managers 

The RHR requires that states consult with Federal Land Managers (FLMs) before 

adopting and submitting their SIPs. 40 CFR 51.308(i). States must provide FLMs an 

opportunity for consultation, in person and at least 60 days prior to holding any public 

hearing on the SIP. This consultation must include the opportunity for the FLMs to 

discuss their assessment ofvisibility impairment in any Class I area and to offer 

recommendations on the development of the reasonable progress goals and on the 

development and implementation of strategies to address visibility impairment. Further, 

a state must include in its SIP a description ofhow it addressed any comments provided 

by the FLMs. Finally, a SIP must provide procedures for continuing consultation 

between the state and FLMs regarding the state's visibility protection program, including 

development and review of SIP revisions, five-year progress reports, and the 

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implementation of other programs having the potential to contribute to impairment of 

visibility in Class I areas. 

D. Best Available Retrofit Technology 

Section 169A ofthe CAA directs states to evaluate the use ofretrofit controls at certain 

larger, often uncontrolled, older stationary sources in order to address visibility impacts from 

these sources. Specifically, section 169A(b)(2)(A) ofthe CAA requires states to revise their 

SIPs to contain such measures as may be necessary to make reasonable progress towards the 

natural visibility goal, including a requirement that certain categories of existing major stationary 

sources 

7 built between 1962 and 1977 procure, install, and operate the "Best Available Retrofit 

Technology" as determined by the state. States are directed to conduct BART determinations 

for such sources that may be anticipated to cause or contribute to any visibility impairment in a 

Class I area. Rather than requiring source-specific BART controls, states also have the 

flexibility to adopt an emissions trading program or other alternative program as long as the 

alternative provides greater reasonable progress towards improving visibility than BART. 

On July 6, 2005, EPA published the Guidelinesfor BART Determinations Under the 

Regional Haze Rule at appendix Y to 40 CFR Part 51 (hereinafter referred to as the "BART 

Guidelines") to assist states in determining which oftheir sources should be subject to the BART 

requirements and in determining appropriate emission limits for each applicable source. In 

making a BART applicability determination for a fossil fuel-fired electric generating plant with a 

total generating capacity in excess of 750 megawatts, a state must use the approach set forth in 

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

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the BART Guidelines. A state is encouraged, but not required, to follow the BART Guidelines 

in making BART determinations for other types of sources. 

States must address all visibility-impairing pollutants emitted by a source in the BART 

determination process. The most significant visibility impairing pollutants are S02, NOx, and 

PM. EPA has indicated that states should use their best judgment in determining whether V OC 

or NH3 compounds impair visibility in Class I areas. 

The RPOs provided air quality modeling to the states to help them in determining 

whether potential BART sources can be reasonably expected to cause or contribute to visibility 

impairment in a Class I area. Under the BART Guidelines, states may select an exemption 

threshold value for their BART modeling, below which a BART-eligible source would not be 

expected to cause or contribute to visibility impairment in any Class I area. The state must 

document this exemption threshold value in the SIP and must state the basis for its selection of 

that value. Any source with emissions that model above the threshold value would be subject to 

a BART determination review. The BART Guidelines acknowledge varying circumstances 

affecting different Class I areas. States should consider the number of emission sources affecting 

the Class I areas at issue and the magnitude ofthe individual sources' impacts. Generally, an 

exemption threshold set by the state should not be higher than 0.5 deciview. 

In their SIPs, states must identify potential BART sources, described as "BART-eligible 

sources" in the RHR, and document their BART control determination analyses. The term 

"BART-eligible source" used in the BART Guidelines means the collection of individual 

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emission units at a facility that together comprises the BART-eligible source. In making BART 

determinations, section 1 69A(g)(2) of the CAA requires that states consider the following 

factors: (1) the costs of compliance, (2) the energy and non-air quality environmental impacts of 

compliance, (3) any existing pollution control technology in use at the source, (4) the remaining 

useful life ofthe source, and (5) the degree ofimprovement in visibility which may reasonably 

be anticipated to result from the use of such technology. States are free to detennine the weight 

and significance to be assigned to each factor. 

A regional haze SIP must include source-specific BART emission limits and compliance 

schedules for each source subject to BART. Once a state has made its BART determination, the 

BART controls must be installed and in operation as expeditiously as practicable, but no later 

than five years after the date EPA approves the regional haze SIP. CAA section 169(g)(4)). 40 

CFR 51.308(e)(1)(iv). In addition to what is required by the RHR, general SIP requirements 

mandate that the SIP must also include all regulatory requirements related to monitoring, 

recordkeeping, and reporting for the BART controls on the source. States have the flexibility to 

choose the type of control measures they will use to meet the requirements ofBART . 

. III. EPA-'s Analysis of Idaho Regional Haze SIP 

A. Affected Class I Areas 

There are five mandatory Class I areas, or portions ofsuch areas, within Idaho. Craters of 

the Moon National Monument, Sawtooth Wilderness Area, and Selway-Bitterroot Wilderness 

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Area lie completely within Idaho State borders. Hells Canyon Wilderness Area is a shared Class 

I area with Oregon, and Yellowstone National Park is a shared Class I area with Wyoming. See 

40 CFR 81.410. Oregon and Wyoming respectively will address reasonable progress goals, 

monitoring, and other core requirements for these Class I areas. Idaho consulted with Oregon 

and Wyoming to determine Idaho's contribution to regional haze in those Class I areas and to 

determine appropriate measures for Idaho's long-term strategy. See chapter 13, section 13.2 of 

the Idaho Regional Haze SIP submittal. See also the WRAP Technical Support DocumentS 

(WRAP TSD) supporting this action 

The Idaho SIP submittal addresses the three Class I areas that are completely within the 

State border and, as appropriate, Class I areas with shared jurisdiction with Oregon and 

Wyoming and Class I areas in neighboring states. 

B. Baseline and Natural Conditions 

Idaho, using data from the IMPROVE monitoring network and analyzed by WRAP, 

established baseline and natural visibility conditions as well as the uniform rate of progress 

(URP) to achieve natural visibility conditions in 2064 for all Idaho Class I areas within its 

borders. While Idaho is responsible for establishing baseline and natural conditions for three 

Class I areas, the SIP also included these values for Hells Canyon Wilderness Area and 

Yellowstone National Park, as determined by WRAP and established by Oregon and Wyoming. 

8 EPA evaluated the technical work products of the WRAP used by Idaho in support if this Regional Haze SIP 

submittaL The results of that evaluation are included in the document "WRAP Technical Support Document" or 

WRAP TSD. 

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Baseline visibility was calculated from monitoring data collected by IMPROVE monitors 

for the most-impaired (20 % worst) days and the least-impaired (20 % best) days. Idaho used the 

WRAP derived natural visibility conditions. In general, WRAP based their estimates on EPA 

guidance, Guidance for Estimating Natural Visibility Conditions Under the Regional Haze 

Program (EPA-45/B-03-0005 September 2003) but incorporated refinements which EPA 

believes provides results more appropriate for western states than the general EPA default 

approach. See section 2.E of the WRAP TSD. 

Craters of the Moon National Monument: An IMPROVE monitor is located in 

Craters ofthe Moon National Monument. Based on baseline 2000 to 2004 data, the average 20% 

worst days visibility is 14 dv and the average 20% best days visibility is 4.3 dv. Natural 

visibility for the average 20% worst days is 7.53 dv. 

Hells Canyon Wilderness Area: Hells Canyon Wilderness Area has an IMPROVE 

monitor located within the Wilderness Area at Oxbow Dam. Based on baseline 2000 to 2004 

data, Oregon determined the average 20% worst days visibility is 18.55 dv and the average 20% 

best days visibility is 5.52 dv. Natural visibility for the average 20% worst days is 8.32 dv. 

Sawtooth Wilderness Area: Sawtooth Wilderness Area has an IMPROVE monitor 

located within the Wilderness Area. Based on baseline 2000 to 2004 data, the average 20% 

worst days visibility is 13.78 dv and the average 20% best days visibility is 3.99 dv. Natural 

visibility for the average 20% worst days is 6.42 dv. 

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Selway-Bitterroot Wilderness Area: Selway-Bitterroot Wilderness Area visibility is 

represented by an IMPROVE monitor located 20 km east ofthe Wilderness Area in Sula, 

Montana. This site also represents visibility in the Anaconda-Pinder Wilderness Area. Based on 

baseline 2000 to 2004 data, the average 20% worst days visibility is 13.41 dv and the average 

20% best days visibility is 2.58 dv for both areas. Natural visibility for the Selway-Bitteroot and 

the Anaconda-Pinder Wilderness Areas average 20% worst days is 7.43 dv. 

Yellowstone National Park: Yellowstone National Park has an IMPROVE monitor 

located within the park. Based on baseline 2000 to 2004 data Wyoming determined the average 

20% worst days visibility is 11.76 dv and the average 20% best days visibility is 2.58 dv. 

Natural visibility for the average 20% worst days is 6.24 dv. 

Based on our evaluation ofthe State's baseline and natural conditions analysis, EPA is 

proposing to find that Idaho has appropriately determined baseline visibility for the average 20% 

worst and 20% best days and natural visibility conditions for the average 20% worst days in each 

Class I area within the state. See the WRAP TSD supporting this action (section 2.D and 2.E). 

C. Idaho Emission Inventories 

There are three main categories of air pollution emission sources: point sources, area 

sources, and mobile sources. Point sources are larger stationary sources that emit pollutants 

through a stack or duct. Area sources are large numbers ofsmall sources that are widely 

distributed across an area, such as residential heating units or re-entrained dust from unpaved 

21 

roads or windblown dust fonn agricultural fields. Mobile sources are sources such as motor 

vehicles, locomotives and aircraft. 

The RHR requires a statewide emission inventory ofpollutants that are reasonably 

anticipated to cause or contribute to visibility impainnent in any mandatory Class I area. 40 

CFR S1.308(d)(4)(v). The WRAP, with data supplied by the states, compiled emission 

inventories for all major source categories in Idaho for the 2002 baseline year and estimated 

emission inventories for 2018. Emission estimates for 2018 were generated from anticipated 

population growth, growth in industrial activity, and emission reductions from implementation of 

control measures, e.g., implementation ofBART limitations, and motor vehicle tailpipe 

emissions. Appendix D ofthe Idaho Regional Haze SIP discusses how emission estimates were 

detennined and contains the emission inventory. Detailed estimates ofthe emissions, used in the 

modeling conducted by the WRAP and Idaho, can be found at the WRAP website: 

http://vista.cira.coiostate.eduITSS/Results/Emissions.aspx 

There are a number of emission inventory source categories identified in the Idaho SIP: 

point, area, on-road mobile, off-road mobile, anthropogenic fire (prescribed forest fire, 

agricultural field burning, and residential wood combustion), natural fire, road dust, fugitive dust 

and windblown dust. The 2002 baseline and 2018 projected emissions, as well as the net 

changes of emissions between these two years, are presented in Tables 8-1 through 8-8 in the SIP 

submittal for S02, NOx, Volatile Organic Carbon (VOC), Organic Carbon (OC), Elemental 

Carbon (EC), fine particulate (PM2.5), coarse particulate (PM coarse) and ammonia. The 

methods that WRAP used to develop these emission inventories are described in more detail in 

22 

the WRAP TSD. As explained in the WRAP TSD, emissions were calculated using best 

available data and approved EPA methods. See WRAP TSD section 12. 

S02 emissions in Idaho corne mostly from coal combustion at industrial boilers and from 

other industrial activities. S02 emissions estimates for point sources carne either from source 

test data (where available) or calculations based on fuel type and quantity burned. These 

industrial point sources contribute 45% oftotal statewide S02 emissions. The second largest 

contributor to S02 emissions in Idaho is fire: 31 % from natural fire and 2% from anthropogenic 

fire. 

Idaho projects a 45% statewide reduction in point source S02 emissions by 2018 due to 

implementation ofBART emission limitations. Idaho also proj ects total 2018 statewide S02 

emissions to be reduced by 33.9% below 2002 levels as a result ofBART and additional 

reductions from mobile sources and anthropogenic fire emissions. According to the State's 

analysis, overall point source emissions, the largest source category in 2002, are projected to be 

reduced by 46.7%. Area source emissions (8% of statewide S02 emissions) are projected to 

increase 7.9% between 2002 and 2018 due to population growth. Idaho projects S02 emissions 

associated with natural fire, the second largest source category in 2002, to remain unchanged and 

would become the largest source category in 2018. 

NOx emissions in Idaho come mostly from mobile sources, both from on-road and offroad mobile sources, which contribute 46% of total statewide NOx emissions. The second 

largest source category ofNO x emissions is area source emissions from combustion to heat 

23 

buildings. Area source emissions account for 19% ofstatewide NOx emissions. Idaho projects 

that 2018 total statewide emissions ofNO x will be 20.6% lower than 2002 levels. Idaho also 

projects on-road and off-road mobile source emissions to be reduced by 72.4% and 38.3% 

respectively by 2018, due to new Federal motor vehicle emission standards and fleet turnover. 

Idaho projects area source NOx emissions to increase by 38.8% to become the largest source 

category in 2018 due to population growth and new industrial sources. Idaho projects natural 

fire emissions to remain unchanged and become the second largest NOx source category in 2018. 

Volatile organic compounds (VOC) in Idaho come mostly from area sources such as 

industrial solvent use, paints, pharmaceuticals, and refrigerants, which contribute 46% of total 

VOC emissions. The second largest source category in VOC emissions is non-anthropogenic 

fire which contributes 25% oftotal VOC emissions, while the second largest source category of 

anthropogenic VOC is mobile sources. Idaho projects 2018 statewide VOC emissions to 

increase by 19.2% over 2002 levels even though on-road mobile, off-road mobile and 

anthropogenic VOC emissions are projected to decrease 61.7%, 32.2% and 52.3% respectively. 

This increase in VOC emissions is due to a projected 64.2% increase in area source VOC 

emissions primarily due to population growth and increased business activity. 

Organic carbon in Idaho comes from natural fire, anthropogenic fire and mobile sources. 

Natural fire is the largest source category, which contributes 82% oforganic carbon emissions. 

The second largest source category is anthropogenic fire which contributes 15% ofthe total 

organic carbon emissions. Idaho projects 2018 statewide organic carbon emissions to decrease 

24 

7.6% from 2002 emission levels due to reductions in on-road mobile, off-road mobile, and 

anthropogenic fire of 10.8%,43.1 % and 51.6% respectively. 

Elemental carbon is associated with incomplete combustion. The largest source category 

is natural fire, which contributes 72% of total elemental carbon emissions. The second largest 

source category is off-road mobile sources (diesel) which contributes 14% oftotal elemental 

carbon emissions. Idaho projects 2018 statewide elemental carbon emissions to decrease by 

50.7% from 2002 emission levels. These projected reductions are the result of anticipated 

emission reductions in on-road mobile and off-road mobile emissions of73.8% and 64.3% 

respectively. 

Fine particulate, particles with an aerodynamic diameter ofless than 2.5 micrometers, is 

emitted from a variety of area sources. Point sources account for only 2% ofstatewide fine 

particulate. Wind blown dust is the largest source category contributing 26% oftotal fine 

particulate. Wood stoves and small manufacturing and industrial sources contribute 24% oftotal 

fine particulate. Natural fire, anthropogenic fire, road dust and other fugitive dust sources also 

emit approximately equal amounts of fine particulate. Idaho projects that 2018 fine particulate 

emissions will increase by 12.1 % over 2002 emission levels due to population and industrial 

growth. Emissions increases are projected from point, area, road dust, fugitive dust at 26.8%, 

33.6%, 32.0%, and 30.1 % respectively. Fine particulate emissions associated with anthropogenic 

fire are expected to decrease by 53.6%. 

25 

Coarse particulate is particulate with an aerodynamic diameter between 2.5 and 10 

micrometers. It is composed oflarger particles in wind blown dust, natural fire and other 

particulate from industrial grinding sources. The largest source category is wind blown dust 

which contributes 40% oftotal coarse particulate emissions. The second largest source is natural 

fire which contributes 22% of coarse particulate emissions. Idaho projects that 2018 emissions 

of coarse particulate to increase by 11.9% over 2002 emission levels. Idaho projects course 

particulate emissions from most categories to increase, with the exception of anthropogenic fire 

which will decrease by 51.7%. 

Ammonia does not directly impair visibility but can be a precursor to the formation of 

particulate in the atmosphere through chemical reaction with S02 and NOx to form a "secondary 

aerosol". Area sources are the primary source category contributing to ammonia emissions and 

account for 85% oftotal ammonia emissions. The second largest source category is natural fire 

which contributes 10% of ammonia emissions. Idaho projects ammonia emissions in 2018 to 

increase by 1.3% over 2002 emission levels with increasing emissions in all categories with the 

exception of anthropogenic fire which Idaho projects to decrease by 53.4%. 

D. Sources of Visibility Impairment in Idaho Class I Areas 

Each pollutant species has its own visibility impairing property; 1 uglm3 of sulfate, for 

example, is more effective in scattering light than 1 uglm3 of organic carbon and therefore 

impairs visibility more than organic carbon. Following the approach recommended by the 

WRAP and as explain more fully below, Idaho used a two step process to identify the 

26 

contribution of each source or source category to existing visibility impainnent. First, ambient 

pollutant concentration by species (sulfate, nitrate, organic carbon, fine particulate, etc) was 

detennined from the IMPROVE sampler in each Class I area. These concentrations were then 

converted into deciview values to distribute existing impainnent among the measured pollutant 

species. This calculation used the "improved IMPROVE equation" (See section 2.C ofthe 

WRAP TSD) to calculate extinction from each pollutant specie concentration. Extinction, in 

inverse megameters, was then converted to deciview using the equation defining deciview. 

Second, the Comprehensive Air Quality Model with Extensions (CAMx) and PM Source 

Apportionment Technology (PSAT) models were used to detennine which sources and source 

categories contributed to the ambient concentration of each pollutant species. Thus, impainnent 

was distributed by source and source category. 

After considering the available models, the WRAP and Western States selected two 

source apportionment analysis tools. The first source apportionment tool was the Comprehensive 

Air Quality Model with Extensions (CAM x) in conjunction with PM Source Apportionment 

Technology (PSAT). This model uses emission source characterization, meteorology and 

atmospheric chemistry for aerosol fonnation to predict pollutant concentrations in the Class I 

area. The predicted results are compared to measured concentrations to assess accuracy of 

model output. CAMx PSAT modeling was used to detennine source contribution to ambient 

sulfate and nitrate concentrations. The WRAP used state-of-the-science source apportionment 

tools within a widely used photochemical model. EPA has reviewed the PSAT analysis and 

considers the modeling, methodology, and analysis acceptable. See section 6.A of the WRAP 

TSD. 

27 

The second tool was the Weighted Emissions Potential (WEP) model, used primarily as a 

screening tool to decide which geographic source regions have the potential to contribute to haze 

at specific Class I areas. WEP does not account for atmospheric chemistry (secondary aerosol 

formation) or removal processes, and thus is used for estimating inert particulate concentrations. 

The model uses back trajectory wind flow calculations and resident time of an air parcel to 

determine source and source category and location for ambient organic carbon, elemental carbon, 

PM2.5, and coarse PM concentrations. These modeling tools were the state-of-the-science and 

EPA has determined that these tools were appropriately used by WRAP for regional haze 

planning. Description ofthese tools and our evaluation ofthem are described in more detail in 

section 6 ofthe WRAP TSD. 

Figure 7-1 in the Idaho Regional Haze SIP submittal presents the light extinction for the 

base year at each Class I area by visibility impairing pollutant species for the average ofthe 20% 

worst days. The visibility impairing pollutant species identified are: fine particulate (i.e. sea 

salt, fine soil, elemental carbon, organic carbon, ammonium sulfate and ammonium nitrate) and 

coarse material. In addition the SIP submission identifies in Figures 7.2 through Figure 7.52, 

light extinction by pollutant species for the average ofthe 20% worst and average ofthe 20% 

best days for each of the Class I areas. 

Figure 7-1 ofthe SIP indicates that on the 20% worst days organic carbon is the primary 

pollutant impairing visibility in the Sawtooth and Selway-Bitterroot Wilderness Areas. In 

28 

Craters ofthe Moon National Monument the primary pollutant impairing visibility on the 20% 

worst days is ammonium nitrate. 

Idaho also analyzed the monthly variation oflight extinction and pollutant specie 

concentrations for the 20% worst days. See Idaho SIP Figures 7-6 and 7-7, Figures 7-24 through 

7-27, Figures 7-35 through 7-38. Each Class I area shows a distinct monthly and seasonal 

variation in impairment. For example, the 20% worst days in Craters ofthe Moon National 

Monument occur during the winter months of December through February. The 20% worst days 

in the Sawtooth and Selway-Bitterroot Wilderness Areas occur from April through November. 

This variation in impairment is due to monthly and seasonal variation in meteorology and 

emission rates. 

To determine potential impacts of emission sources in Idaho on Class I areas in other 

states, Idaho considered the WRAP analysis ofinterstate impacts. Ambient air sulfate and nitrate 

concentrations for the 20% worst and best days for baseline (2002-2004) and 2018 at each 

western Class I area is distributed among all states in the WRAP using PSAT modeling. The SIP 

submittal provides an analysis ofthe Class I areas in nearby states. See chapter 9.3 of the Idaho 

Regional Haze SIP submission. These Class I areas are: 

Shared Class I Areas with Oregon and Wyoming 

• Hells Canyon Wilderness Area 

• Yellowstone National Park 

29 

Class I Areas outside Idaho 

• 	 Glacier National Park in Montana: Idaho is ranked 3rd behind Montana and Washington 

in contribution of visibility impairing pollutants on the 20% worst days 

• 	 Cabinet Mountain Wilderness Area in Montana: Idaho is ranked 3rd behind Oregon and 

Washington in contribution to visibility impairing pollutants on the 20% worst days 

• 	 Bob Marshall Wilderness Area in Montana: Idaho is ranked 3rd behind Montana and 

Washington in contribution to visibility impairing pollutants on the 20% worst days 

• 	 Gates of the Mountain Wilderness in Montana: Idaho is 'ranked 3rd , behind Montana and 

Washington in contribution to visibility impairing pollutants on the 20% worst days 

• 	 North Absaroka Wilderness in Wyoming: Idaho is ranked 2nd behind Wyoming in 

contribution to visibility impairing pollutants on the 20% worst days 

• 	 Bridger Wilderness in Wyoming: Idaho is ranked 2nd behind Wyoming in contribution to 

visibility impairing pollutants on the 20% worst days 

• 	 Eagle Cap Wilderness Area Oregon: Idaho is ranked 3rd behind Oregon and Washington 

in contribution to visibility impairing pollutant on the 20% worst days 

• 	 Jarbidge Wilderness Area in Nevada: Idaho is ranked 1

51 in contribution ofsulfate and 

nitrate to the Jarbidge Wilderness area. 

EP A is proposing to find that Idaho has appropriately identified the primary pollutants 

impacting its Class I areas. EPA is also proposing to find that the SIP contains an appropriate 

analysis ofthe impacts of emissions from Idaho on nearby Class I areas. 

E. 	Best Available Retrofit Technology 

30 
The first phase of a BART evaluation is to identify all the BART -eligible sources within 

the State's boundaries. Table 10-1 in the SIP submission presents the list of all BART -eligible 

sources located in Idaho. These sources are: The Amalgamated Sugar Company (TASCa) in 

Twin Falls, TASCa in Nampa, TAsca in Paul, NU West/Agrium in Soda Springs, the l.R. 

Simplot Don Plant in Pocatello, the Monsanto/P4 Production LLC facility at Soda Springs, and 

the Potlatch Pulp & Paper mill in Lewiston Idaho. 

The second phase ofthe BART determination process is to identify those BART-eligible 

sources that may reasonably be anticipated to cause or contribute to any impairment ofvisibility 

at any Class I area and are, therefore, subject to BART. As explained above, EPA has issued 

guidelines that provide states with guidance for addressing the BART requirements. 40 CFR 

Part 51 appendix Y; see also 70 Fed. Reg. 39,104 (July 6,2005). The BART Guidelines 

describe how states may consider exempting some BART-eligible sources from further BART 

review based on dispersion modeling showing that the sources contribute below a certain 

threshold amount. Idaho conducted dispersion modeling for the BART-eligible sources to 

determine the visibility impacts ofthese sources on Class I areas with the exception of the 

Monsanto/P4 Production LLC facility which was categorized as subject to BART without 

analysis. 9 

The BART Guidelines require States to set a contribution threshold to assess whether the 

impact of a single source is sufficient to cause or contribute to visibility impairment at a Class I 

area. Generally, States may not establish a contribution threshold that exceeds 0.5 dv impact. 70 

9 Monsanto agreed to forego exemption modeling and to move directly to a BART determination. 

31 
Fed. Reg. at 39,161. Idaho established a contribution threshold of 0.5 dv through negotiated 

rulemaking with industry, FLMs, and the public. In its SIP submittal, Idaho notes that the 0.5 dv 

threshold is also consistent with the threshold used by all other states in the WRAP. Any source 

with an impact of greater than 0.5 dv in any Class I area, including Class I areas in other states, 

would be subject to a BART analysis and BART emission limitations. 

The explanation given by Idaho for adopting a 0.5 dv threshold for determining whether a 

BART source may be reasonably anticipated to cause or contribute to any visibility impairment 

in a Class I area is not adequate to justify the selection of such a threshold. Although a number 

ofstakeholders may have agreed that a 0.5 dv threshold is appropriate, and other states in the 

Region may have adopted such a threshold, such agreement does not provide sufficient basis 

concluding that such a threshold was appropriate in the case ofIdaho. Based on EPA's review 

of the BART-eligible sources in Idaho, however, EPA is proposing to find that a 0.5 dv threshold 

is appropriate, given the specific facts in Idaho. 

In the BART Guidelines, EPA recommended that States "consider the number of BART 

sources affecting the Class I areas at issue and the magnitude of the individual sources' impacts. 

In general, a larger number of BART sources causing impacts in a Class I area may warrant a 

lower contribution threshold." 70 FR 39104,39161 July 6,2005. In developing its regional 

haze SIP, Idaho modeled the impacts of six of the seven BART-eligible sources on Class I areas 

within a 300 km radius. (See Table 10-3 through Table 10-8 of the SIP submittal). As noted 

above, the State and Monsanto/P4 Production mutually agreed that Monsanto/P4 was subject to 

BART. Ofthese BART-eligible sources, only TASCO, Nampa exceeded the 0.5 dv threshold, 

32 

based on consideration ofthe 22nd highest impact during 2003-2005. 10 For the remaining five 

BART-eligible sources~ the modeling showed maximum impacts below 0.4 dv. These sources 

are generally widely distributed across the State~ and only TASCO Twin Falls and TASCO Paul 

showed modeled impacts affecting the same Class I area. Given the relatively limited impact on 

visibility from these sources~ Idaho could have reasonably concluded that a 0.5 dv threshold was 

appropriate for capturing those BART -eligible sources with significant impacts on visibility in 

Class I areas. For these reasons~ EPA is proposing to approve the 0.5 dv threshold adopted by 

Idaho in its Regional Haze SIP. 

To determine those sources subject to BART~ Idaho used the CALPUFF model. The 

dispersion modeling was conducted in accord with the BARTModeling Protocol7. This Protocol 

was jointly developed by the states of Idaho, Washington, Oregon and EPA and has undergone 

public review. The Protocol was used by all three states in determining which BART-eligible 

sources are subject to BART. See appendix F of the SIP submission for details ofthe modeling 

protocol, its application and results. As noted above, Idaho determined through modeling that 

one, ofthe six modeled BART-eligible sources in Idaho, was subject to BART: the TASCO 

facility in Nampa. In addition, the MonsantoIP4 Production LLC facility in Soda Springs was 

determined to be subject to BART based on agreement by the source and the State. 

F. TASCa BART Analysis: 

TASCO Nampa is a sugar beet processing facility that operates a 350 million BTU per 

hour, coal-fired boiler known as the Riley boiler. The Riley boiler emits sulfur dioxide, oxides 

to The 22nd highest impact during 2003-2004 corresponds to the 98th percentile ofmodeling results, an approach to 

applicability that EPA concluded was appropriate in the BART Guidelines. 70 FR at 39,123. 

33 
of nitrogen and particulate matter. It is anticipated to operate into the foreseeable future, thus 

expected life ofthe source is not a factor in the BART determination. 

The first step in a BART analysis is the identification of all available retrofit control 

options. Available retrofit control options are those air pollution control technologies with a 

practical potential for application to the emission unit. 40 CFR 51, appendix Y provides 

guidance on identifying available options that includes review ofEPA's Clean Air Technology 

Center RACT/BACT/LAER clearinghouse, state and local Best Available Control Technology 

Guidelines, and a number of other documents. See 40 CFR 51 appendix Y(IV)(D)(1). Generally 

EPA does not expect states to consider control technologies that have not already been 

demonstrated in practice to be technically feasible. 

Idaho identified the pollutants of concern for the BART determination at the Riley boiler 

to be sulfur dioxide, oxides of nitrogen and particulate matter. BART controls for each pollutant 

will be discussed below. Following an evaluation of available controls, described below, Idaho 

determined that the following emission limits represent BART for the Riley Boiler: 

S02 104 lblhr 

NOx 131 lblhr 

PM 12.4lblhr 

The Idaho Regional Haze SIP submittal includes the federally enforceable Tier II operating 

permit for TASCa, Nampa, (permit No. T2-2009.01 09) that contains these emission limits. See 

letter and attachments dated September 7,2010, from Mike Simon, Stationary Source Manager, 

34 

Idaho Air Quality Division, to Kent Quinney, Plant Manager, The Amalgamated Sugar 

Company, LLC-Nampa Factory. The BART emission limits in the Tier II operating permit are 

slightly higher than those limits in the SIP submittal to allow for slight variation in test method 

results. 

The emission limits for NOx and S02 can be achieved respectively through use of low 

NOx burners with overfire air and spray dry gas desulfurization. BART will result in a 65% 

reduction in S02 emissions and 80% reduction in NOx emissions. Idaho found that the bag 

house currently in place at the facility will result in compliance with the PM BART limitation. 

1. T ASCO S02 BART Evaluation 

The TASCO Riley boiler currently bums low-sulfur coal limited to 1 % sulfur by weight. 

The alternative control options considered for S02 include: low- sulfur coal limited to 0.6% 

sulfur by weight that would provide an additional 15% control efficiency, wet flue gas 

desulfurization (Wet FGD) with a 95% control efficiency, spray dryer flue gas desulfurization 

(Spray Dry FGD) with an 80% control efficiency, dry lime flue gas desulfurization (Dry Lime 

FGD) with a 55% control efficiency, dry Trona flue gas desulfurization (Dry Trona FGD) with a 

65% control efficiency. Idaho found that all these technologies are technically feasible, but, as 

explained below, that wet FGD and spray dry FGD were the best options for further evaluation. 

With a removal efficiency of95% or greater, wet FGD systems offer one ofthe highest 

S02 removal efficiencies ofthe available control technologies. However, the installation of wet 

FGD at TASCO Nampa would require significant modification ofthe facility that would increase 

35 

the cost ofthis option. As explained in the SIP submittal, wet FGD results in a saturated exhaust 

stream. The resulting condensation that would form in the stack would likely have a very low 

pH that would require installation of a stack liner to protect the integrity of the stack. Idaho 

concluded that installation of a stack liner would cost $2,000,000. Cost effectiveness ofwet 

FGD was accordingly estimated at $3353/ton, with an incremental cost of$6940/ton as 

compared to the next most efficient control technology, spray dry FGD. 

Spray dry FGD typically has an estimated control efficiency of 80-90% depending on 

exit flue gas temperature as it approaches the adiabatic saturation temperature. Idaho used SO% 

control efficiency in this evaluation. Cost effectiveness of spray dry FGD is $2163/ton and the 

incremental cost over the next most efficient control technology, dry Trona FGD is $360/ton. 

Idaho also evaluated the energy and non-air related environmental impacts ofthe S02 

control options. Waste-water treatment from wet FGD is a major concern to Idaho and would 

need to be treated onsite. The SIP submittal explains that it would be difficult and expensive to 

expand the TASCO on-site treatment facility due to limited available land and the City ofNampa 

water treatment system might not be able to handle the increased water volume. See State of 

Idaho Department ofEnvironmental Quality, Regional Haze Plan, 10/S/10, appendix F, 

Table 32 of appendix F ofthe SIP submittal provides the estimated visibility impact of 

the five control options. Wet FGD would reduce the number of days with greater than 0.5 dv 

impact over a three year period from 127 days to 43 days. Spray dry FGD would reduce the 

number ofdays with greater than 0.5 dv from 127 days to 51 days. Considering the incremental 

36 

cost of wet FGD over spray dry FGD of $6940/ton, the waste water treatment limitations, and 

achieving a reduction of only 8 more days with impact greater than 0.5 dv over a three year 

period, Idaho concluded that wet FGD is not warranted. 

Idaho has determined that spray dry FGD is the appropriate control technology for S02 

and established 104 lblhr as BART based on cost effectiveness and improvement in visibility. 

EPA agrees with Idaho's BART determination for S02. 

2. NOx BART Evaluation 

Idaho identified potential control options for oxides ofnitrogen (NOx) for the Riley 

boiler as: low NOx burners (LNB) with a 50% control efficiency, low NOx burners with 

overfire air (LNB/OFA) with a 65% control efficiency, ultra low NOx burners (ULNB) which 

was determined to be infeasible, selective catalytic reduction (SCR) with a 90% control 

efficiency, and selective non-catalytic (SNCR) determined to be infeasible. Idaho evaluated the 

technical feasibility of each control option. Idaho found that ULNB is not technologically 

feasible as the fire box at the Riley boiler is not large enough to accommodate the flame 

management system necessary for this type of control. Idaho also concluded that SNCR is also 

not technologically feasible as the boiler exhaust path does not have enough residence time for 

reliable control. Idaho accordingly identified three technically feasible control options: LNB, 

LNB/OFA, and SCR. 

Idaho determined the cost effectiveness and incremental cost effectiveness for the three 

technically feasible control options. See Table 35 of appendix F ofthe SIP submittal. Idaho 

37 

concluded that LNB/OFA provides a reasonable cost effectiveness of $ 1270/ton and incremental 

cost effectiveness of $243Olton over 10w-NOx burners. SCR would provide a 90% reduction in 

NOx emissions at a cost effectiveness of $3768 and incremental cost of $1 0,245/ton over 

LNB/OFA. LNB/OFA would reduce the number of days with impacts greater than 0.5 dv over a 

three year period from 127 days to 56 days. SCR would reduce the number of days with impact 

greater than 0.5 dv over a three year period from 127 days to 40 days. Considering the 

incremental cost of SCR over LNB/OFA of $1 0,245/ton and achieving an incremental reduction 

of 16 days with impact greater than 0.5 dv over a three year period, Idaho concluded SCR is not 

warranted and that LNB/OFA represents BART. In addition, as described below in section F(d), 

TASCO argued that it could not afford to install an SCR. In view ofthis and Idaho's conclusion 

that the incremental cost of $1 0,245/ton for reducing the number of days with an impact greater 

than 0.5dv by 16 over a three year period EPA is proposing to approve Idaho's determination of 

BART forNOx TASCO. 

3. PM BART Evaluation 

The TASCO Nampa Riley boiler has a baghouse to control particulate matter. In its PM 

BART evaluation Idaho considered other alternative control technologies including: an enhanced 

baghouse with a control efficiency of 99%, wet electrostatic precipitator with a control efficiency 

Of 99%, and dry electrostatic precipitator with a control efficiency of 99%. Idaho compared 

these technologies to the control efficiency ofthe current baghouse. The existing baghouse with 

a control efficiency of 99% emits 0.036 Ibs/MMbtu (350 MMbtulhour boiler with a limit of 

0.036lbs/MMbtu the emissions are 12.6Ibslhour). 

38 

Idaho detennined that the existing baghouse is the best BART control technology since it 

will not incur additional cost and has control efficiency comparable to the identified alternate 

control technologies. The existing baghouse has the added environmental benefits of not 

requiring additional water or electricity. The benefit of adding an additional baghouse is so 

small the benefits are outweighed by the costs. In conclusion, the best BART alternative for 

particulate is the existing baghouse. 

Idaho detennined that the current baghouse and an emission limitation of 12.4 lbslhr is 

BART. EPA agrees with this detennination. 

4. T ASCO Affordability 

TASCO appealed to Idaho that the company could not afford the identified BART (Spray 

Dry FOD and LNB/OFA) and remain viable. At Idaho's request, EPA conducted an evaluation 

and analysis ofTASCO's financial status and health. Based on this evaluation, EPA detennined 

TASCO could afford implementation ofthe identified BART. EPA also concluded that TASCO 

could not reasonably afford the more costly control options of Wet FOD for S02 control and 

SCR for NOx control. See Idaho Regional Haze Plan 10/8/1 0, appendix F, page F-317: 

Executive Summary excerpt from: An Affordability Analysis ofThe Amalgamated Sugar 

Company LLC's Affordability Claim with respect to the Best Available Retrofit Technology 

(BART) for the Riley Boiler at the Nampa, Idaho facility, February 12, 201 O. 

Based on EPA's review and evaluation we propose to approve the BART detennination 

forTASCO. 

39 
G. Monsanto/P4 BART Analysis 

MonsantoIP4 Production is a thermal process elemental phosphorus production facility. 

Idaho identified two BART units at the facility: the #5 Rotary Kiln and the #9 Furnace Exhaust 

and carbon monoxide Flare. Phosphate ore is processed in a high temperature electric arc 

furnace in a reducing atmosphere produced by the introduction of coke. Carbon monoxide gas 

from the arc furnace is used as fuel for the #5 Rotary Kiln. Excess carbon monoxide is flared to 

the atmosphere. 

Idaho concluded, as discussed below, that the following emissions limit is BART for #5 

Rotary Kiln: 

S02 143lblhr 

Idaho determined, as discussed below, that there are no technically feasible NOx control 

options for the #9 Furnace Exhaust and CO Flare. 

1. #5 Rotary Kiln, S02 Evaluation: 

Idaho conducted a thorough S02 BART evaluation for the #5 Rotary Kiln. The #5 

Rotary Kiln heats phosphate ore to remove volatile impurities and harden ore nodules for further 

handling and introduction into the electric arc furnace. Carbon monoxide from the furnace off 

gasses is the primary fuel with coal and natural gas as backup. Existing federally-enforceable 

process and air pollution controls for the kiln are included in the facility's current Tier I (title V) 

operating permit No. Tl-2009.0121, issued July 24,2009. These requirements consist of: 

40 

• A limit on the sulfur content of the coal to no more than 1 % by weight. 

• 	 A dust knockout chamber, spray tower, four parallel Hydro-Sonic© scrubbers, and four 

parallel cyclonic separators. The tandem nozzle fixed-throat free-jet scrubbers are 

required for control ofPM/PM 1 0 and polonium-210 emissions (a radionuclide) found in 

the phosphate ore. 

The initial S02 control device is a settling chamber where large particles are removed. The 

exhaust flow is then routed to a concrete tower where it passes through water sprays to remove 

soluble gases and particulate matter. The exhaust flow is then routed to four parallel HydroSonic© scrubbers for removal ofsubmicron particles and entrained particle-laden water. The 

exhaust gases exit the scrubbers and pass though cyclonic separators and fans prior to exiting to 

the atmosphere though four stacks. 

A lime concentrated dual alkali (LCDA) scrubber to control S02 emissions from the kiln 

was installed by Monsanto/P4 in 2005. The LCDA scrubbing process uses the existing HydroSonic© scrubbers to absorb S02 with a solution of sodium salts comprised of sodium sulfite and 

bisulfite, the active absorbent species. Some sodium sulfate will also be produced. The spent 

solution of sodium sulfitelbisulfite/sulfate is continuously withdrawn to a dual-reactor system, 

where it is treated with hydrated lime. The lime regenerates the scrubbing solution and 

precipitates calcium sulfite/sulfate solids. The solids are removed from the system through 

thickening and filtration, and the regenerated solution is returned to the scrubber as feed materiaL 

41 

Additional S02 controls would be add-on (or retrofit) control to the existing control 

technology. Idaho analyzed the technically feasible retrofit control technologies for S02 

emissions from the #5 Rotary Kiln. These alternative controls included; wet FGD with lime and 

amine scrubbing. 

Idaho evaluated the control efficiencies of these feasible technologies and found that both 

are capable of97% control. As determined by Idaho, the costs of these controls are $466/ton for 

wet FGD and $8811ton for amine scrubbing. See appendix F, Table 5.1.1 (page 338) ofthe Idaho 

Regional Haze SIP. The energy impacts were evaluated and both options require more energy, 

but not disproportionate amounts. Neither of the available options constitute significant adverse 

non-air environmental effects. The #5 Rotary Kiln is expected to remain in operation for the life 

ofthe P4 facility. 

Idaho selected wet-FGD with lime as the most suitable control technology based on the 

fact that control efficiency is comparable to amine scrubbing, has a lower cost, and is a proven 

mature technology. Idaho determined that 143 lblhr is BART for the #5 Rotary Kiln. EPA 

agrees with this determination. 

2. #5 Rotary Kiln NOx BART Evaluation 

Idaho searched EPA's RACT/BACT/LAER clearinghouse (RBLC) for potential NOx 

control options. The available options include: combustion control, LNB, and SNCR. 

42 

Idaho detennined that NOx combustion controls are technically infeasible due to the 

temperatures required for sintering the phosphate ore and the change in temperature resulting 

from combustion controL Thennal NOx is fonned at approximately 1300 °c (2372 OF) and 

above. The minimum temperature at which sintering of the phosphate ore occurs is 1400 °c to 

1459 °c (2552 OF to 2658 OF). Therefore, it is not feasible to lower the temperature in the kiln to 

minimize or prevent the fonnation ofthennal NOx and still sinter the ore. 

Likewise, LNB was eliminated because the temperature required for a low NOx burner is 

too low to sinter the phosphate ore and fonn the required nodules. Sintering ofthe ore takes 

place at 1400 °c to 1459 °c, and low NOx burners must be controlled to operate at temperatures 

well below 1300°C (2372 OF), the temperature at which thennal NOx is fonned. 

SNCR was eliminated because the kiln off gas temperature at the exit of the kiln and 

prior to the existing Hydro-Sonic© particulate control is too low for operation of SNCR. 

EPA agrees that there are no technically feasible NOx control options for the #5 Rotary 

Kiln. The current emission limitation is 3750.7 ton/yr. 

3. #S Rotary Kiln Particulate Matter BART Evaluation 

As described above, the #5 Rotary Kiln emissions are currently controlled with HydroSonic© high energy venture scrubbers to control particulate matter. The Tier I operating penni! 

includes a federally enforceable limit of 89.4 tons of PM/year. 

43 

Idaho conducted a brief evaluation of alternative PM control technologies but concluded, 

and EPA agrees, that there are no other technically feasible alternative control technologies with 

greater control efficiency than the existing Hydro-Sonic© high energy venturi scrubbers. Thus, 

the existing PM emission limit of98.4 t/yr constitutes BART for this source. 

4. BART for the #9 Furnace CO Flare Evaluation 

Ore nodules from the #5 Rotary Kiln are combined with coke and quartzite and heated in 

the #9 electric arc furnace. The resulting thermal process releases elemental phosphorus (as a 

gas), carbon monoxide and entrained particulate matter. The furnace off gas is cooled to liquefy 

and collect the elemental phosphorus and the remaining gasses are ducted to the #5 Rotary Kiln 

as fuel. Excess furnace off gas is treated in a thermal oxidizer and flared to the atmosphere. The 

source of concern is the furnace flare, since most ofthe furnace gasses fuel the #5 Rotary kiln 

and are controlled by technology applied to that source. 

A review ofthe RBLC Clearinghouse revealed there are no available control technologies 

for particulate matter, S02, or NOx for the #9 Furnace CO Flare. The RBLC Clearinghouse 

flare control options are exclusively for organic fuels and are not applicable for carbon monoxide 

fueled flares. 

EPA agrees with Idaho's conclusion because there are no known retrofit control 

technologies that are technically feasible for the Monsanto/P4 #9 Furnace Exhaust and CO Flare. 

EPA is proposing to approve the BART determination for Monsanto/P4. 

44 

The Monsanto/P4 BART emission limits are contained in federally enforceable Tier I and 

Tier II operating permits. The BART requirements are contained in the Tier II operating permit, 

T2-2009.0109, issued November 17, 2009. 

H. Improvement in Visibility from BART at TASCO, Nampa and Monsanto/P4 

Table 10-14 ofthe SIP submittal presents the visibility improvement at several Class I 

areas in Idaho and surrounding states from implementation of BART at TASCa Nampa and 

Monsanto/P4. The metric used to measure improvement is the number of days (or reduction in 

number of days) with a deciview impact larger than 0.5 dv from each BART facility over a three 

year period. 

The greatest improvement from BART controls at Monsanto/P4 is seen in the Teton 

Wilderness Area in Wyoming. Idaho estimated a reduction in the number of days with visibility 

impairment greater than 0.5 dv from Monsanto/P4 of 50 days over a three year period. Table 

10-15 of the SIP submittal presents the visibility improvement at several other Class I areas in 

Idaho and surrounding states from implementation of BART at the Monsanto/P4 facility in Soda 

Springs. 

The greatest improvement from BART controls at TASCa Nampa is seen in the Eagle 

Cap Wilderness Area in Oregon, with a reduction in days with greater than 0.5 dv of 127 days 

over a three year period. 

45 

Idaho included in the SIP submittal, federally enforceable Tier I and Tier II operating 

permits for TASCO Nampa and Monsanto/P4 which contain the necessary emission limitations 

representing BART and schedules for compliance. 

IV. EPA's Analysis ofWhether Regional Haze SIP Submittal Meets Interstate Transport 

Requirements 

In its October 25, 20 I 0, transmittal letter, Idaho also indicated that it intends the Regional 

Haze SIP submittal also to be a SIP submission for purposes ofthe visibility requirements of 

section 11 O(a)(2)(D)(i) with respect to the 1997 8-hour ozone and 1997 PM2.5 NAAQS. In the 

submission, Idaho stated that: "Idaho's Regional Haze SIP also satisfies the Clean Air Act 

Interstate Transport requirements of section 11 0(a)(2)(D)(ii). Chapters 2 and 13 and the 

associated appendix for chapter 2 describe Idaho's consultation with other states through the 

WRAP. Chapter 9 identifies Idaho's contribution and future visibility improvements at 

mandatory Class I Federal Areas impacted by Idaho's emissions." In its SIP transmittal letter, 

the state referred to section 11 O(a)(2)(D)(ii), but from the context it is clear that the state 

intended this reference to be to section 11 0(a)(2)(D)(i), and more particularly to section 

11O(a)(2)(D)(i)(U). 

Section 11 0(a)(2)(D)(i)(II) ofthe Act requires SIP revisions to "contain "adequate 

provisions ...prohibiting ...any source or other types of emission activity within the State from 

emitting any air pollutant in amounts which will .. .interfere with measures required to be 

included in the applicable implementation plan for any other State ... to protect visibility." EPA 

46 

is proposing to find that the SIP submitted by Idaho to address regional haze contains adequate 

provisions to meet the "good neighbor" provisions of section 110(a)(2)(D)(i)(II) with respect to 

visibility. 

As an initial matter, EPA notes that section 11O(a)(2)(D)(i)(II) does not explicitly specify 

how EPA should ascertain whether a state's SIP contains adequate provisions to prevent 

emissions from sources in that state from interfering with measures required in another state to 

protect visibility. Thus, the statute is ambiguous on its face, and EPA must interpret that 

provIsIOn. 

Our 2006 Guidance recommended that a state could meet the visibility prong of the 

transport requirements for section 110(a)(2)(D)(i)(II) by submission of the regional haze SIP, 

due in December 2007. EPA's reasoning was that the development of the regional haze SIPs 

was intended to occur in a collaborative environment among the states, and that through this 

process states would coordinate on emissions controls to protect visibility on an interstate basis. 

In fact, in developing their respective reasonable progress goals, WRAP states consulted with 

each other through the WRAP's work groups. As a result of this process, the common 

understanding was that each state would take action to achieve the emissions reductions relied 

upon by other states in their reasonable progress demonstrations under the RHR. This 

interpretation is consistent with the requirement in the regional haze rule that a state participating 

in a regional planning process must include "all measures needed to achieve its apportionment of 

emission reduction obligations agreed upon through that process." 40 CFR S1.308(d)(3)(ii). 

47 

We believe that with approval of the portions of the Idaho RH SIP that we are proposing 

to take action on today, Idaho's SIP will also contain adequate provisions to prevent interstate 

transport that would interfere with the measures required in other states to protect visibility. 

Chapter 13 of the Idaho SIP submittal explains the consultation process followed by Idaho and 

its neighboring states to meet the requirements in the regional haze rule to address the interstate 

transport of visibility impairing pollutants and the outcome of that process. Section 13.2.3 

indicates that Idaho and neighboring states agreed that "no major contributions were identified 

that supported developing new interstate strategies, mitigation measures, or emissions reductions 

obligations," and that each state could achieve its share of emission reductions through the 

implementation of BART and other existing measures in state regional haze plans. The state 

agreed that future consultation would address any new strategies or measures needed. The 

measures addressing BART in the Idaho SIP submittal accordingly would appear to be adequate 

to prevent emissions from source in Idaho from interfering with the measures required to be in 

the regional haze SIPs of its neighbors. 

This conclusion is consistent with the analysis conducted by the WRAP, an analysis that 

provides an appropriate means for further evaluating whether emissions from sources in a state 

are interfering with the visibility programs of other states, as contemplated in section 

11O(a)(2)(D)(i)(II). As described below, EPA's evaluation shows that the BART measures of 

the Regional Haze SIP submittal, that we are proposing to approve today, are generally 

consistent with the emissions reductions assumptions ofthe WRAP modeling from Idaho 

sources. Accordingly, EPA is proposing to approve Idaho's SIP as ensuring that emissions from 

Idaho do not interfere with the reasonable progress goals of other states. 

48 
In developing their visibility projections using photochemical grid modeling, the WRAP 

states assumed a certain level of emissions from sources within Idaho. The visibility projection 

modeling was in turn used by the states to establish their own reasonable progress goals. We 

have reviewed the WRAP photochemical modeling emissions projections used in the 

demonstration ofreasonable progress towards natural visibility conditions and compared them to 

the emissions limits that will result from the imposition of BART on sources in Idaho. We have 

concluded that with the emissions reductions achieved by these measures, the emissions from 

Idaho sources in the projected inventory for 2018 (which included both reductions and increases) 

will be below that assumed in the WRAP analysis. In addition, EPA notes that these projections 

also included estimated emissions from a new coal fired power plant to be located in Jerome, 

Idaho. The Governor ofIdaho subsequently issued a ban on the construction ofnew coal fired 

power plants that is still in effect. Thus, EPA anticipates that the actual emissions in 2018 may 

be significantly less than the emissions used in modeling 2018 conditions because the Jerome, 

Idaho facility will likely not be constructed during the time period covered by the Regional Haze 

SIP. 

As a result of the foregoing determination, EPA is proposing to find that the Idaho 

Regional Haze SIP submission contains the emission reductions needed to achieve Idaho's share 

of emission reductions agreed upon through the regional planning process. As reflected in its 

Regional Haze SIP submittal, Idaho committed to achieve these emission reductions to address 

impacts on visibility on Class I areas in surrounding states. The portions of the Idaho Regional 

Haze SIP that we are proposing to approve ensure that emissions from Idaho will not interfere 

49 

with the reasonable progress goals for neighboring state's Class I areas. EPA is accordingly 

proposing to find that these emission reductions also meet the requirements ofsection 

110(a)(2)(D)(i)(II) ofthe Act with respect to the visibility prong for the 1997 8-hour ozone and 

1997 PM2.5 NAAQS. 

V. What Action is EPA Proposing? 

EPA is proposing to approve portions ofthe Idaho Regional Haze plan, submitted on 

October 25,2010, as meeting the requirements set forth in section 169A ofthe Act and in 40 

CFR 51.3 08( e) regarding BART . EPA is also proposing to approve the Idaho submittal as 

meeting the requirements of 51.308(d)(2) and (4)(v) regarding the calculation ofbaseline and 

natural conditions for Craters ofthe Moon National Monument, Sawtooth Wilderness Area, and 

Selway-bitterroot Wilderness, and the statewide inventory of emissions of pollutants that are 

reasonably anticipated to cause or contribute to visibility impairment in any mandatory Class I 

Federal Area. In addition, EPA is proposing to find that the BART measures in the Idaho 

Regional Haze plan meet the requirements of section 11 O(a)(D)(ii)(II) of the CAA with respect 

to the 1997 8-hour ozone and 1997 PM2.5 NAAQS 

VI. Scope of Action 

50 

Idaho has not demonstrated authority to implement and enforce IDAP A chapter 58 within 

"Indian Country" as defined in 18 U.S.C. 115l." Therefore, EPA proposes that this SIP 

approval not extend to "Indian Country" in Idaho. See CAA sections llO(a)(2)(A) (SIP shall 

include enforceable emission limits), 11 0(a)(2)(E)(i) (State must have adequate authority under 

State law to carry out SIP), and 172(c)(6) (nonattainment SIPs shall include enforceable emission 

limits). This is consistent with EPA's previous approval of Idaho's prevention of significant 

deterioration (PSD) program, in which EPA specifically disapproved the program for sources 

within Indian Reservations in Idaho because the State had not shown it had authority to regulate 

such sources. See 40 CFR 52.683(b). It is also consistent with EPA's approval ofIdaho's title V 

air operating permits program. See 61 FR 64622, 64623 (December 6, 1996) (interim approval 

does not extend to Indian Country); 66 FR 50574, 50575 (October 4, 2001) (full approval does 

not extend to Indian Country). 

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 Act and applicable Federal regulations. 42 U.S.c. 7410(k); 

""Indian country" is defined under 18 U.S.C. 1151 as: (1) all land within the limits of any 

Indian reservation under the jurisdiction of the United States Government, notwithstanding the 

issuance of any patent, and including rights-of-way running through the reservation, (2) all 

dependent Indian communities within the borders of the United States, whether within the 

original or subsequently acquired territory thereof, and whether within or without the limits of a 

State, and (3) all Indian allotments, the Indian titles to which have not been extinguished, 

including rights-of-way running through the same. Under this definition, EPA treats as 

reservations trust lands validly set aside for the use of a Tribe even if the trust lands have not 

been formally designated as a reservation. In Idaho, Indian country includes, but is not limited 

to, the Coeur d'Alene Reservation, the Duck Valley Reservation, the Reservation ofthe Kootenai 

Tribe, the Fort Hall Indian Reservation, and the Nez Perce Reservation as described in the 1863 

Nez Perce Treaty. 

51 
40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, 

provided that they meet the criteria of the Clean Air Act. Accordingly, this proposed action 

merely approves 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 Order 12866 (58 FR 51735, October 4, 1993); 

• 	 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 ofsmall 

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 (Public Law 

104-4); 

• 	 does not have Federalism implications as specified in Executive Order 13132 (64 FR 

43255, August 10, 1999); 

• 	 is not an economically significant regulatory action based on health or safety risks subject 

to Executive Order 13045 (62 FR 19885, April 23, 1997); 

• 	 is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, 

May 22, 2001); 

• 	 is not subject to requirements of Section 12(d) ofthe 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; and 

52 
• 	 does not provide EPA with the discretionary authority to address, as appropriate, 

disproportionate human health or environmental effects, using practicable and legally 

permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994). 

In addition, this rule does not have tribal implications as specified by Executive Order 13175 (65 

FR 67249, November 9,2000), because the SIP is not approved to apply in Indian country 

located in the state, and EPA notes that it will not impose substantial direct costs on tribal 

governments or preempt tribal law. 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air pollution control, Intergovernmental relations, Nitrogen 

dioxide, Particulate matter, Reporting and recordkeeping requirements, Sulfur oxides, visibility, 

and Volatile organic compounds. 

Dated: [ [ Z'Z- r (0 

us:c~ 1'!..C!fl 22 20' 0 

Region 10. 

53