ENVIRONMENTAL PROTECTION AGENCY 40 CFRPart 52 [EPA-RIO-OAR-2010-1072, FRLApproval and Promulgation ofImplementation Plans; State ofIdaho; 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 bythe State ofIdaho on October 25, 2010, as meeting therequirements ofCleanAir Act (CAA) section llO(a)(2)(D)(i)(II) as it applies to visibility for the 1997 8-hourozone and 1997 particulatematter (PM2.5) National Ambient Air Quality Standards (NAAQS). EPA is also proposingto approve a portion ofthe revision as meeting certain requirements ofthe regional haze program, includingtherequirements for best availableretrofit technology (BART).
DATES: Written comments must bereceived at the address below on orbefore [insert date 30 days from the date ofpublication in the Federal Register]
ADDRESSES: Submit your comments, identified byDocket 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 ofAir, 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 ofAir, Waste and Toxics, AWT-I07. Such deliveries are onlyaccepted during normal hours ofoperation, and special arrangements shouldbe made for deliveries ofboxed information. Instructions: Direct your comments to Docket 10No. EPA-R1 0-OAR-2010-1072. EP

### Ns policy is that all comments received will beincluded inthepublic docket without change and maybe made available online at www.regulations.gov, including anypersonal informationprovided, unless the comment includes information claimed to be Confidential Business Information (CBI) orother information whose disclosure is restricted by statute. Do not submitinformationthat you considerto be CBI orotherwise protected through www.regulations.gov ore-mail. The www.regulations.gov Web site is an "anonymous access" system, which means EPA will not know your identityor contact information unless you provide it in the body ofyour 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 ofthe comment that isplaced in thepublic docket and made available on the Internet. Ifyou submit an electronic comment, EPA recommends that you include yourname and othercontact information in the bodyofyour comment and**wit~** anydisk orCD-ROM you submit. IfEPA cannotread your comment due to technical difficulties and cannot contact you for clarification, EPAmaynot be able to consider your comment. Electronic files should avoid the use ofspecial characters, any form of encryption, andbe free ofany defects orviruses.


### 2Docket: 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 restrictedby statute). Certain othermaterial, such as copyrighted material, will bepublicly 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 contactthe individual listed in the
FOR FURTHER INFORMATION CONTACT: Steve Body at telephone number (206) 553­ 0782, body.steve@epa.gov, orthe above EPA, Region 10 address.
SUPPLEMENTARY INFORMATION: Throughout this document whenever "we," "us," or "our" is used, wemean the EPA. Information is organized as follows: Table ofContents I. Background for 

### EPA's Proposed Action

A. Definition ofRegional 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

3D. Best AvailableRetrofit Technology 

### III. EPA's Analysis ofthe Idaho Regional Haze SIP

A. Affected Class I Areas B. Baseline and Natural Conditions C. Idaho Emissions Inventories D. Sources ofVisibility Impairment in Idaho Class I Areas E. Best Available Retrofit Technology F. TASCaBARTAnalysis O. Monsanto/P4 BARTAnalysis H. Improvement in Visibility from BART at TASCa, Nampa and Monsanto/P4 

### IV. EPA's Analysis ofWhetherRegional Haze SIP SubmittalMeets InterstateTransport Requirements V. WhatAction is EPA Proposing? VI. Scope ofAction VII. Statutory and Executive OrderReviews

I. Backgroundfor EPA's Proposed Action
In the CAAAmendments 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 visibilityprovisions in the CAA in 1990 to focus attention on theproblem ofregional haze. See CAA section 169(B). EPApromulgatedregulations in 1999 to implement sections 169A and 169B ofthe Act. Theseregulations require states to develop and implement

4plans to ensure reasonable progress toward improving visibility inmandatory 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 ofbaseline and natural visibility conditions, and the statewideinventory ofvisibilityimpairingpollutants. EPA is also proposing to approve the provisions ofIdaho's SIP submittal addressing BART as meeting Idaho's obligations under section 11O(a)(2)(D)(i)(I) ofthe Act for visibility. EPA is not taking actiontoday onthose provisions ofthe Regional Haze SIP submittal related to reasonable progress goals and the longterm strategy.



### A. Definition ofRegional Haze Regional haze is impairment ofvisual range or colorization caused by emission ofair pollutionproducedby 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 ofnational 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 ofthe CAA, EPA, in consultation with the DepartmentofInterior, promulgated a list of 156 areas where visibility is identified as an important value. 44 FR 69122 (November 30, 1979). The extent ofa mandatory Class I area includes subsequent changes in boundaries, such as parkexpansions. 42 U.S.C. 7472(a). Although states and tribes may designate as Class I additional areas which theyconsider to have visibility as an important value, the requirements ofthe visibility program set forth in section 169Aofthe CAA apply only to "mandatory Class I Federal areas." Each mandatory Class IFederal area is the responsibility ofa "Federal Land Manager." 42 U.S.C. 7602(i). When we use the term "ClassI area" in this action, we mean a "mandatory Class I Federal area." 5fine particulate matter (PM2.5) or secondary aerosol formed inthe atmosphere from precursor gasses (e.g., sulfurdioxide, nitrogen oxides, and in some cases, ammonia and volatile organic compounds). Atmospheric fine particulatereduces clarity, color, and visual range ofvisual scenes. Visibilityreducing 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 inhumans, and contributes to environmental effects such as acid deposition and eutrophication.2

Data from the existing visibilitymonitoringnetwork, the "InteragencyMonitoring of Protected Visual Environments" (IMPROVE) monitoringnetwork, show that visibility impairment causedby air pollution occurs virtually all thetime at most national parks and wilderness areas. Average visual range in many Class I areas intheWestern United States is 100-150 kilometers, or about one-halfto two-thirds the visual range that would exist without manmade airpollution. 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 ofthe CAA establishes as a national goal the "prevention ofanyfuture, and the remedying ofany existing,
2 

### See 64 FRat 35715. 

### 3Id. 6

### impainnent ofvisibilityin Class I areas which impainnentresults from manmade air pollution." CAA section 169A(a)(I). On December 2, 1980, EPA promulgated regulations to address visibilityimpainnent 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 ofsources until monitoring, modeling and scientificknowledge about the relationships between pollutants and visibilityimpainnent 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 visibilityregulations to integrate into the regulation provisions addressing regional haze impainnent and established a comprehensive visibilityprotection 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 visibilityprotection regulations at 40 CFR 51.300-309. Some ofthe main elements ofthe regional hazerequirementsare summarized in section III ofthis rulemaking. Therequirement 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 addressingregional haze visibilityimpainnent no later than December 17,2007.
C. Roles ofAgencies in AddressingRegional Haze
4Albuquerque/Bemalillo County in New Mexico must also submit a regional haze SIP to completely satisfy the requirements ofsection 11O(a)(2)(D) ofthe CAAfor the entire State ofNewMexico under the New Mexico Air Quality Control Act (section 74-2-4). 

### 7Successful implementation ofthe regional haze program will require long-tenn regional coordination among states, tribal governments and various Federal agencies. As noted above, pollution affecting the air qualityin Class I areas canbetransported over long distances, even hundreds ofkilometers. Therefore, to effectively address the problem ofvisibility impainnentin Class I areas, states need to develop strategies in coordination with one another, taking into account the effect ofemissions from onejurisdiction on the airquality 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. Fiveregional planningorganizations (RPOs) were created nationallyto address regional haze and related issues. One ofthemain objectives ofthe RPOs is to develop and analyze data and conduct pollutant transport modeling to assist the States orTribes in developing their regional haze plans.
The Western Regional Air Partnership (WRAP), one ofthe five RPOs nationally, is a voluntarypartnership ofState, Tribal, Federal, and local air agencies dealing with air qualityin 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 ofKumeyaay Indians, Confederated Salish and Kootenai Tribes, Cortina Indian Rancheria, Hopi Tribe, Hualapai Nation ofthe Grand Canyon, Native Village ofShungnak, Nez Perce Tribe, Northern CheyenneTribe, Pueblo ofAcoma, Pueblo ofSan Felipe, and Shoshone-BannockTribes ofFort Hall.

8D. Interstate Transportfor Visibility
On July 18, 1997, EPA promulgated new NAAQS for 8-hour ozone and for PM2.S. 62 FR 

### 386S2. Section 110(a)(1) ofthe CAA requires states to submit a planto address certain requirements for a new orrevised NAAQS within three years after promulgation ofsuch standards, orwithin such shorter time as EPA mayprescribe. Section 11O(a)(2) ofthe 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 ofcertain emissions.
OnApril 

### 2S, 200S, EPA published a "FindingofFailure 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 ofemissions affectingvisibility and started a 2-year clock for thepromulgation ofa 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). Wedeveloped the 2006 Guidance to make recommendations to states for making submissions to meet the requirements ofsection 11O(a)(2)(D)(i) for the 1997 8-hour ozone standards and the 1997 PM2.S standards.

9As 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 110(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 whichwill: (1) contribute significantly to nonattainment ofthe NAAQS in other states; (2) interfere withmaintenance of theNAAQS in other states; (3) interfere withprovisions to prevent significant deterioration ofair quality in other states; or (4) interferewith efforts to protect visibilityin other states.
With respect to establishing that emissions from sources in the statewould not interfere withmeasures in other states to protectvisibility, the 2006 Guidancerecommended that states make a submission indicating thatit was premature, at that time, to detemlinewhether there would be any interference withmeasures in the applicable SIP for another state designed to "protect visibility"until the submission and approval ofregional haze SIPs. Regional haze SIPs wererequired to be submitted byDecember 17,2007. See 74 FR 2392. At this laterpoint in time, however, EPAbelieves it is now necessary to evaluate such 110(a)(2)(D)(i) submissions from a state to ensure that the existing SIP, orthe SIP as modified bythe submission, contains adequate provisions to prevent interference with thevisibilityprograms ofother states, such as for consistency with the assumptions for controls relied upon by other states in establishing reasonableprogress goals to address regional haze.

10The regional haze program, as reflected inthe RHR, recognizes the importance ofaddressing the long-range transport ofpollutants 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 reasonableprogress goals for neighboring Class I areas. States working together through a regional planningprocess, are required to address an agreed upon share oftheircontribution 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 containmeasures that will achieve these emissions reductions, and that these measures will meet the requirements ofsection 110(a)(2)(D)(i).
As a result ofthe regional planning efforts in the West, all states in theWRAP region contributed information to a Technical Support System (TSS) whichprovides an analysis ofthe causes ofhaze, and the levels ofcontribution from all sources within each state to the visibility degradation ofeach Class I area. TheWRAP States consulted in the developmentofreasonable progress goals, using the products ofthis technical consultation process to co-develop their reasonable progress goals for the Western Class I areas. Themodeling donebythe WRAP relied on assumptions regarding emissions overtherelevant planningperiod and embedded in these assumptions were anticipated emissions reductions in each ofthe States in theWRAP, including reductions from BART and othermeasures to be adopted as part ofthe State's longterm strategy for addressing regional haze. The reasonable progress goals in the draft and final regional haze SIPs that have now beenpreparedby States in the West accordingly arebased, in part, onthe emissions reductions from nearby States that were agreed on through the WRAP process.

11Idaho submitted a Regional Haze SIP on October 25,2010, to address the requirements of the RHR and thegood neighborprovisions ofsection 11O(a)(2)(D)(i) regarding visibility for the 1997 8-hourozoneNAAQS 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 ofIdaho'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 ofsection 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 BARTmeasures 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 169A 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 onAugust 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).. 12for the purpose ofeliminating orreducing visibility impairment. The specific regional haze SIP requirements are discussed in further detail below.


### B. Determination ofBaseline, Natural, and CurrentVisibility Conditions
The RHR establishes the deciview (dv) as the principal metric for measuring visibility. This visibility metric expresses uniform changes in haziness in terms ofcommon increments across the entirerange ofvisibility conditions, from pristine to extremelyhazy conditions. Visibility is determined bymeasuringthe 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 trackingprogress in improving visibility, because eachdeciview change is an equal incremental change in visibilityperceivedbythe human eye. Most people candetect a change in visibility at one deciview. 6
The deciview is used in expressingreasonableprogress goals (which are interim visibility goals towards meeting the national visibility goal), definingbaseline, current, and natural conditions, and tracking changes in visibility. Theregional haze SIPs must contain measures that ensure "reasonableprogress" toward the national goal ofpreventing and remedying visibility impairment in Class I areas caused bymanmade airpollution byreducing anthropogenic emissions that cause regional haze. The national goal is a return to natural conditions, i.e., manmade sources ofairpollution would no longer impairvisibility in Class I areas.

6The preamble to the RHR provides additional details aboutthe deciview. 64 FR 35714, 35725 (July 1, 1999). 13

### To track changes in visibility over time at each ofthe 156 Class I areas covered by the visibilityprogram (40 CFR 81.401-437), and as part ofthe process for determining reasonable progress, states must calculate the degree ofexistingvisibility impairment at each Class I area at the time ofeach regional haze SIP submittal and periodicallyreview 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 ofthe 20% least impaired (''best'') and 20% mostimpaired ("worst") visibility days over a specified timeperiod at eachof their Class I areas. In addition, states must also develop an estimate ofnatural visibility conditions for the purpose ofcomparing progress toward the national goaL Natural visibility is determined by estimating thenatural concentrations ofpollutants that cause visibility impairment and then calculating total light extinction based onthose estimates. EPA has provided guidance to states regarding how to calculate baseline, natural and current visibility conditions in documents titled, EPA's Guidance for EstimatingNatural Visibility Conditions Under the RegionalHaze Rule, 

### September2003, (EPA-454/B-03-005 

### located at http://www.epa.gov/ttncaaalitlImemorandairh envcurhr gd.pdf), (hereinafter referred to as "EPA's 2003 Natural Visibility Guidance"), and Guidancefor Tracking Progress Under the RegionalHaze Rule 

### (EPA-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 byDecember 17, 2007, "baselinevisibility conditions" were the starting points for assessing "current" visibility impairment. Baseline visibility conditions represent the degree ofvisibility impairment for the 20% least impaired days

14

### and 20% most impaired days for each calendar year from 2000 to 2004. Using monitoring data for 2000 through 2004, states arerequired to calculate the average degree ofvisibility impairment for each Class I area, based on the average ofannual values overthe five-year period. The comparison ofinitial baseline visibility conditions to natural visibilityconditions indicates the amount ofimprovement necessaryto attain natural visibility, while the future comparison ofbaseline conditions to the then current conditions will indicate the amount of progress made. In general, the 2000
- 2004 baselinetime period is considered thetime 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 submittingtheir 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 onthe development ofthe reasonable progress goals and on the development and implementation ofstrategies to address visibility impairment. Further, a state must include in its SIP a description ofhow it addressed any comments provided bythe FLMs. Finally, a SIP must provide procedures for continuing consultation between the state and FLMs regarding the state's visibilityprotection program, including development and review ofSIP revisions, five-year progress reports, and the

15implementation ofotherprograms havingthe potential to contribute to impairment of visibility in Class I areas.


### D. BestAvailable Retrofit Technology
Section 169A ofthe CAA directs states to evaluate the use ofretrofit controls at certain larger, often uncontrolled, older stationary sources in orderto address visibility impacts from these sources. Specifically, section 169A(b)(2)(A) ofthe CAArequires states to revise their SIPs to contain such measures as maybe necessaryto make reasonable progress towards the natural visibility goal, including a requirement that certain categories ofexistingmajor stationary sources7builtbetween 1962 and 1977procure, install, and operate the "BestAvailable Retrofit Technology" as determined bythe state. States are directedto conduct BART determinations for such sources that maybe 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 tradingprogram orother alternativeprogram as long as the alternative provides greater reasonableprogress towards improving visibility than BART.
OnJuly 6, 2005, EPApublished the Guidelinesfor BARTDeterminations Under the RegionalHaze Rule at appendix Y to 40 CFR Part 51 (hereinafter referred to as the "BART Guidelines") to assist states in determining which oftheir sources shouldbe 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 of750 megawatts, a state must usethe approach set forth in
7The set of"major stationary sources" potentially subject to BART is listed inCAA section 169A(g)(7). 16the BART Guidelines. A state is encouraged, but notrequired, to follow the BART Guidelines inmakingBARTdeterminations for othertypes ofsources.
States must address all visibility-impairing pollutants emitted by a source inthe BART determination process. The most significant visibility impairing pollutants are S02, NOx, and PM. EPA has indicated that states should use theirbestjudgmentindeterminingwhether VOC orNH3 compounds impairvisibility in Class I areas.
The RPOs provided airquality modeling to the states to help them indetermining whetherpotential BART sources canbereasonably expected to cause or contribute to visibility impairment in a Class I area. Underthe BART Guidelines, states may select an exemption threshold value for theirBARTmodeling, below which a BART-eligible source would not be expected to cause orcontribute to visibility impairmentin any Class I area. The state must documentthis exemption threshold value in the SIP and must state thebasis for its selection of that value. Any source with emissions that model above the threshold value would be subjectto a BART determination review. The BART Guidelines acknowledge varying circumstances affecting different Class I areas. States should considerthe number ofemission sources affecting the Class I areas at issue and the magnitude ofthe individual sources' impacts. Generally, an exemption threshold setbythe state should not be higher than 0.5 deciview.
In their SIPs, states must identify potential BART sources, described as "BART-eligible sources" inthe RHR, and document their BART control determination analyses. The term "BART-eligible source" used inthe BART Guidelines means the collection ofindividual

17

### emission units at a facility that together comprises the BART-eligible source. In making BART determinations, section 1 69A(g)(2) ofthe CAA requires that states considerthe following factors: (1) the costs ofcompliance, (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 ofsuch technology. States are free to detennine the weight and significance to be assigned to each factor.
Aregional 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 beinstalled 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 bythe RHR, general SIP requirements mandate that the SIP must also include all regulatoryrequirements related to monitoring, recordkeeping, and reporting for the BART controls on the source. States have the flexibility to choose the type ofcontrol measures theywill use to meet therequirements ofBART.



### . III. EPA-'s Analysis ofIdahoRegional Haze SIP

A. Affected Class I Areas
There are five mandatory Class I 

### areas, orportions ofsuch areas, within Idaho. Craters of the Moon National Monument, Sawtooth Wilderness Area, and Selway-BitterrootWilderness

18Area lie completelywithin Idaho Stateborders. 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 Wyomingrespectively 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) supportingthis action
The Idaho SIP submittal addresses the three Class I areas that are completely within the Stateborder and, as appropriate, Class I areas with sharedjurisdiction 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 byWRAP, established baseline and natural visibility conditions as well as the uniform rate ofprogress (URP) to achieve natural visibility conditions in 2064 for all Idaho Class I areas within its borders. While Idaho is responsible for establishingbaseline 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 byWRAP and establishedby Oregon and Wyoming.

8 EPA evaluated the technical workproducts ofthe WRAP used byIdaho in support ifthis Regional Haze SIP submittaL The results ofthat evaluation are included in the document "WRAPTechnical Support Document" or WRAP TSD. 

### 19

### 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 forEstimatingNatural Visibility Conditions Under the RegionalHaze 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 ofthe WRAP TSD.
Craters ofthe Moon National Monument: 

### An IMPROVE monitor is located in Craters ofthe MoonNational Monument. Based onbaseline 2000 to 2004 data, the average 20% worst days visibilityis 14 dv and the average 20% best days visibility is 4.3 dv. Natural visibilityfor 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. Basedon 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 onbaseline 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.

20Selway-BitterrootWilderness Area: Selway-Bitterroot Wilderness Area visibilityis representedby an IMPROVE monitor located 20 km east ofthe Wilderness Area in Sula, Montana. This site also represents visibility inthe 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 visibilityis 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 IMPROVEmonitor located within thepark. Basedonbaseline 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% worstdays is 6.24 dv.
Based on ourevaluation ofthe State'sbaseline and natural conditions analysis, EPA is proposing to find that Idaho has appropriatelydetermined baseline visibility for the average 20% worst and 20%best days and natural visibilityconditions for the average 20% worst days in each Class I area within the state. Seethe WRAP TSD supporting this action (section2.D and 2.E).
C. Idaho Emission Inventories
There are three main categories ofairpollution emission sources: point sources, area sources, and mobile sources. Point sources are larger stationary sources that emitpollutants through a stack or duct. Area sources are large numbers ofsmall sources that are widely distributed across an area, such as residential heatingunits orre-entrained dust from unpaved

21roads orwindblown 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 orcontribute to visibilityimpainnent in any mandatory Class I area. 40 CFR S1.308(d)(4)(v). TheWRAP, with data suppliedby 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 motorvehicletailpipe 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 bythe WRAP and Idaho, can be found at the WRAP website: http://vista.cira.coiostate.eduITSS/Results/Emissions.aspx
There are a number ofemission 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 ofemissions 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), coarseparticulate (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 quantityburned. These industrial point sources contribute45% oftotal statewide S02 emissions. The second largest contributorto 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 dueto implementation ofBART emission limitations. Idaho also projects 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. Accordingto the State's analysis, overall point source emissions, the largest source category in 2002, are projected to be reduced by46.7%. Area source emissions (8% ofstatewide S02 emissions) areprojected 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 categoryin 2018.
NOx emissions in Idaho come mostlyfrom mobile sources, both from on-road and offroad mobile sources, which contribute 46% oftotal statewideNOx emissions. The second largest source category ofNOx emissions is area source emissions from combustionto heat

23buildings. Area source emissions account for 19% ofstatewide NOx emissions. Idaho projects that 2018 total statewide emissions ofNOx will be 20.6% lower than 2002 levels. Idaho also projects on-road and off-road mobile source emissions to bereducedby 72.4% and 38.3% respectivelyby2018, 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 andbecome the second largestNOx source categoryin 2018.
Volatile organic compounds (VOC) in Idaho come mostly from area sources such as industrial solvent use, paints, pharmaceuticals, and refrigerants, which contribute46% oftotal VOC emissions. The second largest source categoryin VOC emissions is non-anthropogenic fire which contributes 25% oftotal VOC emissions, while the second largest source categoryof anthropogenic VOC ismobile 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 primarilydueto 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

247.6% 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. Thelargest source category is natural fire, which contributes 72% oftotal elemental carbon emissions. The second largest source categoryis off-roadmobile sources (diesel) which contributes 14% oftotal elemental carbon emissions. Idaho projects 2018 statewide elemental carbon emissions to decreaseby 50.7% from 2002 emission levels. These projected reductions are the result ofanticipated emission reductions in on-road mobile and off-roadmobile emissions of73.8% and 64.3% respectively.
Fineparticulate, particles with an aerodynamic diameteroflessthan 2.5 micrometers, is emitted from a variety ofarea sources. Point sources account for only 2% ofstatewide fine particulate. Windblown 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 otherfugitive dust sources also emit approximately equal amounts offine 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. Fineparticulate emissions associated with anthropogenic fire are expected to decrease by 53.6%.

25Coarseparticulate is particulate with an aerodynamic diameterbetween 2.5 and 10 micrometers. Itis composed oflargerparticles in windblown dust, natural fire and other particulate from industrial grinding sources. Thelargest source category is windblown dust which contributes 40% oftotal coarse particulate emissions. The second largest source is natural fire which contributes 22% ofcoarse particulate emissions. Idaho projects that 2018 emissions ofcoarseparticulate to increaseby 11.9% over 2002 emission levels. Idaho projects course particulate emissions from most categories to increase, with the exception ofanthropogenic fire which will decreaseby 51.7%.
Ammonia does not directly impair visibilitybut can bea precursorto the formation of particulate in the atmosphere through chemical reaction with S02 and NOxto 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 categoryis natural fire which contributes 10% ofammonia emissions. Idaho projects ammonia emissions in 2018 to increaseby 1.3% over2002 emission levels with increasing emissions in all categories with the exception ofanthropogenic fire which Idaho projects to decrease by 53.4%.
D. 

### Sources ofVisibility Impairment in Idaho Class I 

### Areas
Eachpollutant species has its own visibility impairing property; 1 uglm3 ofsulfate, for example, is more effective in scatteringlight than 1 uglm3 oforganic carbon and therefore impairs visibilitymore 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 ofeach 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 ComprehensiveAirQualityModel with Extensions (CAMx) and PM Source Apportionment Technology (PSAT) models were used to detennine which sources and source categories contributed to the ambient concentration ofeach pollutant species. Thus, impainnent was distributed by source and source category.
After consideringthe 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 (CAMx) in conjunction with PM Source Apportionment Technology (PSAT). This model uses emission source characterization, meteorology and atmospheric chemistry for aerosol fonnation to predictpollutant concentrations in the Class I area. Thepredicted 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. TheWRAP 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 ofthe WRAP TSD.


### 27

### The second tool was the Weighted Emissions Potential (WEP) model, used primarily as a screeningtool to decide which geographic source regions have thepotential to contribute to haze at specific Class I areas. WEP does not account for atmospheric chemistry (secondary aerosol formation) orremoval processes, and thus is used for estimating inert particulate concentrations. The model uses back trajectorywind flow calculations and resident time ofan airparcel to determine source and source categoryand 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 appropriatelyusedbyWRAP for regional haze planning. Description ofthese tools and our evaluation ofthem are described in more detail in section 6 oftheWRAP TSD. Figure 7-1 in the Idaho Regional Haze SIP submittal presents the light extinction for the base year at each Class I area byvisibilityimpairing pollutant species for the average ofthe 20% worst days. Thevisibility impairingpollutant 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 extinctionbypollutant species for the average ofthe20% worst and average ofthe 20% best days for each ofthe Class I areas. Figure 7-1 ofthe SIP indicates that onthe 20% worst days organic carbon is the primary pollutant impairing visibility in the Sawtooth and Selway-Bitterroot Wilderness Areas. In



### 28Craters ofthe Moon National Monument theprimarypollutant 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 inimpairment. For example, the 20% worst days in Craters ofthe MoonNational Monument occur during the winter months ofDecemberthrough 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 inmeteorology and emission rates.
To determinepotential impacts ofemission 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 ofthe Idaho Regional Haze SIP submission. These Class I areas are:
Shared Class I Areas with Oregon and Wyoming • Hells Canyon Wilderness Area • YellowstoneNational Park



### 29Class I Areas outside Idaho
• Glacier National Park in Montana: Idaho is ranked 3rd behind Montana and Washington in contribution ofvisibility impairingpollutants on the 20% worst days
• Cabinet Mountain Wilderness Area inMontana: Idaho is ranked 3rd behind Oregon and Washington incontribution 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 impairingpollutants on the 20% worst days
• Gates ofthe Mountain Wilderness in Montana: Idaho is 'ranked 3rd , behind Montana and Washington in contribution to visibilityimpairingpollutants 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
• BridgerWilderness in Wyoming: Idaho is ranked 2nd behind Wyoming in contribution to visibility impairingpollutants onthe 20% worst days
• Eagle Cap Wilderness Area Oregon: Idaho isranked 3rd behind Oregon and Washington in contribution to visibility impairingpollutant on the 20% worst days
• Jarbidge Wilderness Area inNevada: Idaho is ranked 151 in contributionofsulfate and nitrate to the Jarbidge Wilderness area.
EPA isproposingto find that Idaho has appropriately identified theprimary pollutants impactingits Class I areas. EPAis also proposing to find that the SIP contains an appropriate analysis ofthe impacts ofemissions from Idaho on nearby Class I areas.


### E. Best Available Retrofit Technology
30

### The first phase ofa 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 ofall 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 identifythose BART-eligible sources that mayreasonablybe 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 contributebelow 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 ofthe Monsanto/P4 Production LLC facility which was categorized as subject to BARTwithout analysis. 9


### The BART Guidelines require States to set a contribution threshold to assess whetherthe impact ofa single source is sufficient to cause or contribute to visibility impairment at a Class I 

### area. Generally, States maynot 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 of0.5 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 ofgreater 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 maybe reasonably anticipated to cause or contribute to any visibility impairment in a Class I area is not adequate tojustifythe selection ofsuch athreshold. Although a number ofstakeholders mayhave agreed that a 0.5 dv threshold is appropriate, and other states in the Region mayhave adopted such athreshold, such agreement does not provide sufficient basis concluding that such a threshold was appropriate in the case ofIdaho. Based onEPA'sreview ofthe 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 "considerthe number ofBART sources affecting the Class I areas at issue and the magnitude ofthe individual sources' impacts. In general, a largernumber ofBART 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 ofsix ofthe seven BART-eligible sources on Class I areas within a 300 km 

### radius. (See Table 10-3 through Table 10-8 ofthe SIP submittal). As noted above, the State and Monsanto/P4 Productionmutually agreed that Monsanto/P4 was subject to BART. Ofthese BART-eligible sources, onlyTASCO, Nampa exceeded the 0.5 dv threshold,

32

### based on consideration ofthe 22nd 

### highest impact during 2003-2005. 10 

### Forthe remaining five BART-eligible**sources~** 

### the modeling showed maximum impacts below 0.4 dv. These sources are generally widely distributed across the**State~** 

### and onlyTASCO 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 adoptedby 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 theBARTModeling Protocol7. This Protocol wasjointlydeveloped bythe states ofIdaho, Washington, Oregon and EPA and has undergone public review. The Protocol was used byall three states in determining which BART-eligible sources are subject to BART. See appendix F ofthe SIP submission for details ofthe modeling protocol, its application and results. As noted above, Idaho determined through modelingthat 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 BARTbased on agreement bythe source and the State.
F. TASCa BART

### Analysis: TASCO Nampa is a sugarbeet processing facility that operates a 350million BTUper hour, coal-fired boilerknown as the Riley boiler. TheRileyboiler emits sulfurdioxide, oxides

to The 22nd highest impact during 2003-2004 corresponds to the 98th percentile ofmodeling results, anapproach to applicabilitythat EPA concluded was appropriate in the BART Guidelines. 70 FRat 39,123. 

### 33

### ofnitrogen 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 ofall available retrofit control options. Availableretrofit 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 ofother documents. See 40 CFR 51 appendix Y(IV)(D)(1). 

### Generally EPA does not expect states to consider control technologies that have not alreadybeen demonstrated inpractice to betechnically feasible.
Idaho identified thepollutants ofconcern for the BART determination at the Rileyboiler to be sulfur dioxide, oxides ofnitrogen and particulatematter. BART controls for eachpollutant will be discussed below. Following an evaluation ofavailable controls, describedbelow, 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 IIoperating permit for TASCa, Nampa, (permit No. T2-2009.0109) that contains these emission limits. See letter and attachments dated September 7,2010, from Mike Simon, Stationary Source Manager,

34Idaho Air QualityDivision, to Kent Quinney, Plant Manager, TheAmalgamated Sugar Company, LLC-Nampa Factory. The BART emission limits in the Tier II operating permit are slightly higher thanthose limits in the SIP submittal to allow for slight variation in test method results.
The emission limits for NOx and S02 canbe achieved respectively through use oflow NOxburners with overfire air and spray dry gas desulfurization. BART will result in a 65% reduction in S02 emissions and 80%reduction in NOxemissions. Idaho found that thebag house currently in place at the facility will result in compliance with the PM BARTlimitation.


### 1. TASCO S02 BART Evaluation The TASCO Rileyboiler currentlybums low-sulfur coal limited to 1 % sulfurbyweight. The alternative control options considered for S02 include: low- sulfur coal limitedto 0.6% sulfurbyweight that wouldprovide an additional 15% control efficiency, wet flue gas desulfurization (Wet FGD) with a 95% control efficiency, spraydryer 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 TronaFGD) with a 65% control efficiency. Idaho found that all these technologies are technically feasible, but, as explainedbelow, that wet FGD and spraydryFGD were the best options for further evaluation.
With a removal efficiency of95% or greater, wet FGD systems offer one ofthehighest S02removal efficiencies ofthe available control technologies. However, the installation ofwet FGD at TASCONampa 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 verylow pH that would require installation ofa stack liner to protect the integrity ofthe stack. Idaho concluded that installation ofa 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, spraydry FGD. Spray dry FGD typically has an estimated control efficiencyof80-90% depending on exit flue gas temperature as it approaches the adiabatic saturation temperature. Idaho used SO% control efficiency in this evaluation. Cost effectiveness ofspray dry FGD is 

### $2163/ton and the incremental cost over the next most efficient control technology, dry TronaFGD is 

### $360/ton.
Idaho also evaluated the energy and non-air related environmental impacts ofthe S02 control options. Waste-watertreatment from wet FGD is a major concern to Idaho and would need to be treated onsite. The SIP submittal explains that it wouldbe difficult and expensive to expand the TASCO on-sitetreatment facility due to limited available land and the CityofNampa watertreatment 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 ofappendix F ofthe SIP submittal provides the estimated visibilityimpact of the five control options. Wet FGD would reduce the number ofdays with greaterthan 0.5 dv impact over a three year period from 127 days to 43 days. Spray dry FGD would reduce the number ofdays with greaterthan 0.5 dv from 127 days to 51 days. Considering the incremental

36cost ofwet FGD over spray dry FGD of$6940/ton, the waste water treatment limitations, and achieving a reduction ofonly 8 more days with impact greaterthan 0.5 dv over a three year period, Idaho concluded that wet FGD is not warranted.
Idaho has determined that spraydry FGD is the appropriate control technology for S02 and established 104 lblhr as BARTbased oncost 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 boileras: low NOxburners (LNB) with a 50% control efficiency, low NOx burners with overfire air (LNB/OF A) with a 65% control efficiency, ultra low NOx burners (ULNB) which was determined to beinfeasible, selective catalytic reduction (SCR) with a 90% control efficiency, and selective non-catalytic (SNCR) determined to be infeasible. Idaho evaluated the technical feasibility ofeach control option. Idaho found that ULNB is not technologically feasible as the fire box at the Rileyboileris not large enough to accommodate the flame management system necessary for this type ofcontrol. Idaho also concludedthat SNCR is also not technologically feasible as theboiler exhaust path does not have enoughresidence time for reliable control. Idaho accordinglyidentified three technically feasible control options: LNB, LNB/OF A, and SCR.
Idaho determined the cost effectiveness and incremental cost effectiveness for the three technically feasible control options. SeeTable 35 ofappendix 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$10,245/ton 

### over LNB/OF 

### A. LNB/OF 

### A would reduce the number ofdays with impacts greater than 0.5 dv over a three year period from 127 days to 56 days. SCR would reduce the number ofdays with impact greater than 0.5 dv over a three yearperiod from 127 days to 40 days. Consideringthe incremental cost ofSCR over LNB/OF 

### A of$10,245/ton 

### and achieving an incremental reduction of 16 days with impact greater than 0.5 dv over a three yearperiod, Idaho concluded SCR is not warranted and that LNB/OFA

### represents BART. In addition, as described belowin 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$10,245/ton 

### for reducing the number ofdays with an impact greater than 0.5dvby 16 over a three year period EPA is proposingto approve Idaho's determination of BART forNOx TASCO.


### 3. PM BART Evaluation TheTASCO Nampa Rileyboilerhas abaghouseto control particulate matter. In its PM BART evaluation Idaho considered other alternative control technologies including: an enhanced baghouse with a control efficiency of99%, wet electrostatic precipitator with a control efficiency Of99%, and dry electrostatic precipitatorwith a control efficiencyof99%. Idaho compared these technologies to the control efficiency ofthe currentbaghouse. The existingbaghouse with a control efficiencyof99% emits 0.036 Ibs/MMbtu (350 MMbtulhourboiler with a limit of 0.036lbs/MMbtuthe emissions are 12.6Ibslhour).

38Idaho 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 existingbaghousehas the added environmental benefits ofnot requiring additional water or electricity. Thebenefit ofadding an additional baghouse is so small thebenefits are outweighed bythe costs. In conclusion, thebest BART alternative for particulate is the existing baghouse.
Idaho detennined that the currentbaghouse and an emission limitation of 12.4 lbslhris BART. EPA agrees with this detennination.
4. TASCO Affordability TASCO appealed to Idaho that the company could not afford the identified BART (Spray DryFOD and LNB/OFA) and remainviable. At Idaho's request, EPA conducted an evaluation and analysis ofTASCO's financial status andhealth. Based onthis evaluation, EPA detennined TASCO could afford implementation ofthe identified BART. EPA also concluded that TASCO could not reasonably afford the more costly control options ofWet FOD for S02 control and SCR for NOx control. See Idaho Regional Haze Plan 

### 10/8/10, appendix F, page F-317: Executive Summary excerpt from: An Affordability Analysis ofThe Amalgamated Sugar Company LLC's AffordabilityClaim with respect to the Best Available RetrofitTechnology (BART) for the Riley Boiler at the Nampa, Idaho facility, February 12, 201 O.
Based on EPA'sreview and evaluation wepropose to approve the BART detennination forTASCO.

39G. Monsanto/P4 BART Analysis
MonsantoIP4 Production is athermal 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 ahigh temperature electric arc furnace in areducing atmosphere produced bythe introduction ofcoke. 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. Carbonmonoxide 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) operatingpermit No. Tl-2009.0121, issued July 24,2009. Theserequirements consist of:

40• A limit onthe sulfur content ofthe coal to no more than 1

### % by weight. • A dust knockout chamber, spraytower, four parallel Hydro-Sonic© scrubbers, and four parallel cyclonic separators. Thetandem nozzle fixed-throat free-jet scrubbers are required for control ofPM/PM1 0 and polonium-210 emissions (a radionuclide) found in the phosphate ore.
The initial S02 control device is a settling chamberwhere largeparticles 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. Theexhaust 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 priorto exiting to the atmosphere though four stacks.
A lime concentrated dual alkali (LCDA) scrubber to control S02 emissions from the kiln was installed byMonsanto/P4 in 2005. The LCDA scrubbing process uses the existing HydroSonic© scrubbers to absorb S02 with a solution ofsodium salts comprised ofsodium sulfite and bisulfite, the active absorbent species. Some sodium sulfatewill also beproduced. The spent solution ofsodium sulfitelbisulfite/sulfate is continuously withdrawn to a dual-reactor system, where it is treated with hydrated lime. Thelimeregenerates 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 (orretrofit) 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 ofthese feasible technologies and found that both are capable of97% control. As determined by Idaho, the costs ofthese 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 ofthe 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 comparableto 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 ofthe phosphate ore occurs is 1400 °cto 1459 °c (2552 OF 

### to 2658 OF). 

### Therefore, itis not feasible to lowerthe temperature in the kiln to minimize or prevent the fonnation ofthennalNOx and still sinter the ore. Likewise, LNB was eliminated because the temperature required for a low NOxburner is too low to sinterthe phosphate ore and fonn the required nodules. Sintering ofthe ore takes place at 1400 °cto 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 offgas temperature at the exit ofthe kiln and prior to the existing Hydro-Sonic© particulate control is too low for operation ofSNCR.
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 particulatematter. TheTier I operatingpenni! includes a federally enforceable limit of89.4 tons ofPM/year.

43Idaho conducted a briefevaluation ofalternative PM control technologies but concluded, and EPA agrees, that there are no othertechnically 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. Theresulting thermal process releases elemental phosphorus (as a gas), carbon monoxide and entrained particulate matter. The furnace offgas is cooled to liquefy and collect the elemental phosphorus and the remaining gasses are ducted to the #5 Rotary Kiln as fuel. Excess furnace offgas is treated in a thermal oxidizer and flared to the atmosphere. The source ofconcern is the furnace flare, since most ofthe furnace gasses fuel the #5 Rotarykiln and are controlled bytechnology applied to that source.
A review ofthe RBLC Clearinghouse revealed there are no available control technologies for particulate matter, S02, orNOx 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 conclusionbecause 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.

44The Monsanto/P4 BART emission limits are contained in federally enforceable Tier I and Tier II operatingpermits. The BART requirements are contained in the Tier II operatingpermit, T2-2009.0109, issued November 17, 2009.


### H. Improvementin Visibility from BART atTASCO, Nampa andMonsanto/P4
Table 10-14 ofthe SIP submittal presents the visibility improvement at several Class I areas in Idaho and surrounding states from implementation ofBART at TASCaNampa and Monsanto/P4. The metric used to measure improvement is the number ofdays (orreduction in number ofdays) with a deciview impact larger than 0.5 dv from each BART facility over a three yearperiod.
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 ofdays with visibility impairment greater than 0.5 dv from Monsanto/P4 of50 days over a three yearperiod. Table 10-15 ofthe SIP submittal presents the visibility improvement at several other Class I areas in Idaho and surrounding states from implementation ofBART at the Monsanto/P4 facility in Soda Springs.
The greatest improvement from BART controls at TASCaNampa is seen in the Eagle Cap Wilderness Area in Oregon, with a reduction indays with greater than 0.5 dv of 127 days over athree year period.

45Idaho included in the SIP submittal, federally enforceable Tier I and Tier II operating permits for TASCONampa and Monsanto/P4 which contain the necessary emission limitations representing BART and schedules for compliance.


### IV. EPA's Analysis ofWhetherRegional Haze SIP Submittal Meets InterstateTransport Requirements
In its October 25, 20I0, transmittal letter, Idaho also indicated that it intends theRegional Haze SIP submittal also to bea SIP submission for purposes ofthe visibility requirements of section 11O(a)(2)(D)(i) with respect to the 1997 8-hour ozone and 1997 PM2.5 NAAQS. In the submission, Idaho stated that: "Idaho'sRegional Haze SIP also satisfies the CleanAirAct Interstate Transport requirements ofsection 110(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 mandatoryClass I Federal Areas impacted by Idaho's emissions." In its SIP transmittal letter, the statereferred to section 11O(a)(2)(D)(ii), but from the context it is clearthat the state intended this reference to beto section 110(a)(2)(D)(i), and more particularlyto section 11O(a)(2)(D)(i)(U).
Section 110(a)(2)(D)(i)(II) ofthe Actrequires SIP revisions to "contain "adequate provisions ...prohibiting ...anysource orothertypes ofemission activitywithin the State from emitting anyairpollutant in amounts which will ...interfere with measures required to be included in the applicable implementation plan for any other State ... to protect visibility." EPA

46is proposing to find that the SIP submitted by Idaho to address regional haze contains adequate provisions to meet the "good neighbor" provisions ofsection 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 visibilityprong ofthe transport requirements for section 110(a)(2)(D)(i)(II) by submission ofthe regional haze SIP, due in December 2007. EPA's reasoning was that the development ofthe 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 interstatebasis. In fact, in developing their respective reasonable progress goals, WRAP states consulted with each other through the WRAP's work groups. As a result ofthis process, the common understanding was that each state would take action to achieve the emissions reductions relied upon by other states in their reasonableprogress 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).

47We believe that with approval ofthe portions ofthe 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 ofthe 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 ofvisibility impairing pollutants and the outcome ofthat 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 ofemission reductions through the implementation ofBART and other existing measures in state regional haze plans. The state agreed that future consultation would address any new strategies ormeasures 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 ofits neighbors.
This conclusion is consistent with the analysis conducted bythe WRAP, an analysis that provides an appropriate means for further evaluating whether emissions from sources in a state are interfering with the visibilityprograms ofother 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 isproposing to approve Idaho's SIP as ensuring that emissions from Idaho do not interfere with the reasonable progress goals ofother states.

48

### In developing their visibilityprojections usingphotochemical grid modeling, the WRAP states assumed a certain level ofemissions from sources within Idaho. The visibilityprojection modeling was in turn used bythe states to establish their ownreasonable 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 ofBART on sources in Idaho. Wehave concluded that with the emissions reductions achieved by these measures, the emissions from Idaho sources in the projected inventory for 2018 (which includedboth reductions and increases) will bebelow that assumed inthe WRAP analysis. In addition, EPA notes that these projections also included estimated emissions from a new coal fired powerplant to be located in Jerome, Idaho. The Governor ofIdaho subsequently issued aban onthe construction ofnew coal fired powerplants 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 bythe Regional Haze SIP.
As a result ofthe foregoing determination, EPA is proposingto find that the Idaho Regional Haze SIP submission contains the emission reductions needed to achieve Idaho's share ofemission reductions agreed upon through the regional planningprocess. As reflected in its Regional Haze SIP submittal, Idaho committed to achieve these emission reductions to address impacts onvisibility on Class I areas in surrounding states. Theportions ofthe Idaho Regional Haze SIP that we are proposing to approve ensure that emissions from Idaho will not interfere

49with the reasonableprogress goals for neighboring state's Class I areas. EPA is accordingly proposingto find that these emissionreductions 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 Hazeplan, submitted on October 25,2010, as meeting the requirements set forth in section 169A ofthe Act and in 40 CFR 51.308(e) regarding BART. EPA is also proposingto approve the Idaho submittal as meetingthe requirements of51.308(d)(2) and (4)(v) regardingthe calculationofbaseline and natural conditions for Craters oftheMoon National Monument, SawtoothWilderness Area, and Selway-bitterroot Wilderness, and the statewide inventory ofemissions ofpollutants that are reasonably anticipated to cause orcontribute to visibilityimpairment in anymandatory Class I Federal Area. In addition, EPA is proposing to find that the BART measures in the Idaho Regional Haze plan meet the requirements ofsection 11O(a)(D)(ii)(II) ofthe CAA with respect to the 1997 8-hourozone and 1997 PM2.5 NAAQS

VI. Scope ofAction

50Idaho has not demonstrated authority to implement and enforce IDAPA 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), 110(a)(2)(E)(i) (Statemust have adequate authorityunder 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 ofIdaho's prevention ofsignificant deterioration (PSD) program, in which EPA specificallydisapproved the program for sources within Indian Reservations in Idaho because the State had not shown it had authorityto regulate such sources. See 40 CFR 52.683(b). Itis 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 (October4, 2001) (full approval does not extend to Indian Country).


### VII. Statutory and Executive OrderReviews
Underthe Clean AirAct, the Administratorisrequired to approve a SIP submission that complies with the provisions ofthe Act and applicable Federal regulations. 42 U.S.c. 7410(k); ""Indiancountry" is defined under 18 U.S.C. 1151 as: (1) all land within the limits ofany Indian reservation under thejurisdictionofthe United States Government, notwithstanding the issuance ofanypatent, and including rights-of-way runningthrough the reservation, (2) all dependent Indian communities within the borders ofthe United States, whether within the original or subsequently acquired territorythereof, and whether within orwithout the limits ofa State, and (3) all Indian allotments, the Indian titles to which have not been extinguished, includingrights-of-wayrunning through the same. Under this definition, EPA treats as reservations trust lands validly set aside for the use ofa Tribe even ifthe trust lands havenot been formally designated as a reservation. In Idaho, Indian country includes, butis 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 PerceReservation as described in the 1863 Nez Perce Treaty.
5140 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that theymeet the criteria ofthe 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 "significantregulatory action" subject to review bythe Office ofManagement and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993); • does not impose an information collection burden under the provisions ofthe Paperwork Reduction Act (44 U.S.C. 3501 etseq.); • is certified as nothaving a significant economic impact on a substantial number ofsmall entities under the Regulatory FlexibilityAct (5 U.S.C. 601 etseq.); • does not contain any unfunded mandate or significantlyoruniquely 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 ofSection 12(d) oftheNational TechnologyTransfer and Advancement Act of 1995 (15 U.S.c. 272 note) because application ofthose requirements would be inconsistent with the Clean Air Act; and

52• does not provide EPA with the discretionary authorityto address, as appropriate, disproportionate human health orenvironmental 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 byExecutive Order 13175 (65 FR 67249, November 9,2000), because the SIP is not approved to applyin Indian country located in the state, and EPA notes that 

### it will not impose substantial direct costs on tribal governments orpreempt tribal law.
ListofSubjects in 40 CFR Part 52
Environmental protection, Airpollution control, Intergovernmental relations, Nitrogen dioxide, Particulatematter, Reporting and recordkeepingrequirements, Sulfur oxides, visibility, and Volatile organic compounds.

Dated: [ [Z'Z- 

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