[Federal Register Volume 77, Number 77 (Friday, April 20, 2012)]
[Proposed Rules]
[Pages 23988-24101]
[FR Doc No: 2012-8367]

Vol. 77

Friday,

No. 77

April 20, 2012

Part III

Environmental Protection Agency

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40 CFR Part 52

Approval and Promulgation of Implementation Plans; State of Montana;
State Implementation Plan and Regional Haze Federal Implementation
Plan; Proposed Rule

Federal Register / Vol. 77, No. 77 / Friday, April 20, 2012 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2011-0851; FRL-9655-7]

Approval and Promulgation of Implementation Plans; State of
Montana; State Implementation Plan and Regional Haze Federal
Implementation Plan

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing a
Federal Implementation Plan (FIP) to address regional haze in the State
of Montana. EPA developed this proposal in response to the State's
decision in 2006 to not submit a regional haze State Implementation
Plan (SIP) revision. EPA is proposing to determine that the FIP
satisfies requirements of the Clean Air Act (CAA or ``the Act'') that
require states, or EPA in promulgating a FIP, to assure reasonable
progress towards the national goal of preventing any future and
remedying any existing man-made impairment of visibility in mandatory
Class I areas. In addition, EPA is also proposing to approve a revision
to the Montana SIP submitted by the State of Montana through the
Montana Department of Environmental Quality on February 17, 2012. The
State's submittal contains revisions to the Montana Visibility Plan
that includes amendments to the ``Smoke Management'' section, which
adds a reference to Best Available Control Technology (BACT) as the
visibility control measure for open burning as currently administered
through the State's air quality permit program. This change was made to
meet the requirements of the Regional Haze Rule. EPA will act on the
remaining revisions in the State's submittal in a future action.

DATES: Written comments must be received at the address below on or
before June 19, 2012.
    Public Hearings. We will be holding two public hearings for this
proposal. One hearing is scheduled to be held in Helena, Montana on
Tuesday, May 1, 2012 from 2 p.m. until 5:30 p.m. and from 6:30 p.m.
until 9 p.m. at the Lewis & Clark Library, 120 S. Last Chance Gulch,
Helena, Montana 59601,<PHONE_NUMBER>. The other hearing is scheduled
to be held in Billings, Montana on Wednesday, May 2, 2012 from 1 p.m.
until 5 p.m. and from 6 p.m. until 8 p.m. at the Montana State
University--Downtown Campus, Meeting Room--Broadway III A, 2804 3rd
Avenue North, Billings, Montana 59101,<PHONE_NUMBER>.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2011-0851, by one of the following methods:
     http://www.regulations.gov. Follow the on-line
instructions for submitting comments.
     Email<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER> (please alert the individual listed in
FOR FURTHER INFORMATION CONTACT if you are faxing comments).
     Mail: Carl Daly, Director, Air Program, Environmental
Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595 Wynkoop Street,
Denver, Colorado 80202-1129.
     Hand Delivery: Carl Daly, Director, Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129. Such deliveries are only accepted
Monday through Friday, 8 a.m. to 4:30 p.m., excluding federal holidays.
Special arrangements should be made for deliveries of boxed
information.
    Instructions: Direct your comments to Docket ID No. EPA-R08-OAR-
2011-0851. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://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 http://www.regulations.gov or email. The http://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 email comment directly to EPA, without
going through http://www.regulations.gov, your email 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, EPA recommends that you include your name
and other contact information in the body of your comment and with 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 of special characters, any form of encryption, and be free of
any defects or viruses. For additional instructions on submitting
comments, go to Section I. General Information of the SUPPLEMENTARY
INFORMATION section of this document.
    Docket: All documents in the docket are listed in the http://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.
Publicly-available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Air Program,
Environmental Protection Agency (EPA), Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129. EPA requests that if at all
possible, you contact the individual listed in the FOR FURTHER
INFORMATION CONTACT section to view the hard copy of the docket. You
may view the hard copy of the docket Monday through Friday, 8 a.m. to 4
p.m., excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Vanessa Hinkle, Air Program, U.S.
Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595
Wynkoop, Denver, Colorado 80202-1129,<PHONE_NUMBER>,
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
II. What Action is EPA Proposing to Take?
III. Background
    A. Regional Haze
    B. Requirements of the CAA and EPA's Regional Haze Rule
    C. Roles of Agencies in Addressing Regional Haze
IV. Requirements for a Regional Haze FIP
    A. The CAA and the Regional Haze Rule
    B. EPA's Authority to Promulgate a FIP
    C. Determination of Baseline, Natural, and Current Visibility
Conditions
    D. Determination of Reasonable Progress Goals (RPGs)
    E. Best Available Retrofit Technology (BART)
    F. Long-Term Strategy (LTS)
    G. Coordinating Regional Haze and Reasonably Attributable
Visibility Impairment (RAVI)
    H. Monitoring Strategy and Other Implementation Plan
Requirements
    I. Consultation with States and Federal Land Managers (FLMs)
V. EPA's Analysis of Montana's Regional Haze
    A. Affected Class I Areas
    B. Baseline Visibility, Natural Visibility, and Uniform Rate of
Progress

    1. Estimating Natural Visibility Conditions
    2. Estimating Baseline Conditions
    3. Summary of Baseline and Natural Conditions
    4. Uniform Rate of Progress
    5. Contribution Assessment According to Improve Monitoring Data
    C. BART Determinations
    1. BART-Eligible Sources
    2. Sources Subject to BART
    a. Modeling Methodology
    b. Contribution Threshold
    c. Sources Identified by EPA as BART-Eligible and Subject to
BART
    3. BART Determinations and Federally Enforceable Limits
    a. Visibility Improvement Modeling
    b. BART Five-Factor Determinations and Federally Enforceable
Limits
    i. Ash Grove Cement
    ii. Holcim
    iii. Columbia Falls Aluminum Company (CFAC)
    iv. Colstrip
    (a) Colstrip Unit 1
    (b) Colstrip Unit 2
    v. Corette
    D. Long-Term Strategy/Strategies
    1. Emissions Inventories
    2. Sources of Visibility Impairment in Montana Class I Areas
    3. Other States' Class I Areas Affected by Montana Emissions
    4. Visibility Projection Modeling
    5. Consultation and Emissions Reductions for Other States' Class
I Areas
    6. EPA's Reasonable Progress Goals for Montana
    a. EPA's Use of WRAP Visibility Modeling
    b. EPA's Reasonable Progress ``Four-Factor'' Analysis
    c. Four Factor Analyses for Point Sources
    i. Colstrip Energy Limited Partnership
    ii. Colstrip Unit 3
    iii. Colstrip Unit 4
    iv. Devon Energy Production
    v. Montana-Dakota Utilities Lewis & Clark Station
    vi. Montana Sulphur and Chemical
    vii. Plum Creek Manufacturing
    viii. Roseburg Forest Products
    ix. Smurfit Stone Container
    x. Yellowstone Energy Limited Partnership
    d. Establishment of the Reasonable Progress Goal
    e. Reasonable Progress Consultation
    f. Mandatory Long-Term Strategy Requirements
    i. Reductions Due to Ongoing Air Pollution Programs
    ii. Measures to Mitigate the Impacts of Construction Activities
    iii. Emission Limitations and Schedules for Compliance
    iv. Sources Retirement and Replacement Schedules
    v. Agricultural and Forestry Smoke Management Techniques
    vi. Enforceability of Montana's Measures
    vii. Anticipated Net Effect on Visibility Due to Projected
Changes
    E. Coordination of RAVI and Regional Haze Requirements
    F. Monitoring Strategy and Other Implementation Plan
Requirements
    G. Coordination with FLMs
    H. Periodic FIP Revisions and Five-Year Progress Reports
VI. Proposed Action
VII. Statutory and Executive Order Reviews

Definitions

    For the purpose of this document, we are giving meaning to certain
words or initials as follows:
    i. The words or initials Act or CAA mean or refer to the Clean
Air Act, unless the context indicates otherwise.
    ii. The initials A/F mean or refer to air-to-fuel.
    iii. The initials ARM mean or refer to Administrative Rule of
Montana.
    iv. The initials ARP mean or refer to the acid rain program.
    v. The initials ASOFA mean or refer to advanced separated
overfire air.
    vi. The initials BACT mean or refer to Best Available Control
Technology.
    vii. The initials BART mean or refer to Best Available Retrofit
Technology.
    viii. The initials CAMD mean or refer to EPA Clean Air Markets
Division.
    ix. The initials CAMx mean or refer to Comprehensive Air Quality
Model.
    x. The initials CCM mean or refer to EPA Control Cost Manual.
    xi. The initials CCOFA mean or refer to close-coupled overfire
air system.
    xii. The initials CDS mean or refer to circulating dry scrubber.
    xiii. The initials CELP mean or refer to Colstrip Energy Limited
Partnership.
    xiv. The initials CEMS mean or refer to continuous exhaust
monitoring systems.
    xv. The initials CEPCI mean or refer to Chemical Engineering
Plant Cost Index.
    xvi. The initials CFAC mean or refer to Columbia Falls Aluminum
Company.
    xvii. The initials CFB mean or refer to circulating fluidized
bed.
    xviii. The initials CKD mean or refer to cement kiln dust.
    xix. The initials CMAQ mean or refer to Community Multi-Scale
Air Quality modeling system.
    xx. The initials CO mean or refer to carbon monoxide.
    xxi. The initials CPI mean or refer to Consumer Price Index.
    xxii. The initials CRF mean or refer to Capital Recovery Factor.
    xxiii. The initials DAA mean or refer to Dry Absorbent Addition.
    xxiv. The initials DPCS mean or refer to digital process control
system.
    xxv. The initials D-R mean or refer to Dresser-Rand.
    xxvi. The initials DSI mean or refer to dry sorbent injection.
    xxvii. The initials EC mean or refer to elemental carbon.
    xxviii. The initials EGU mean or refer to Electric Generating
Units.
    xxix. The words EPA, we, us or our mean or refer to the United
States Environmental Protection Agency.
    xxx. The initials ESP mean or refer to electrostatic
precipitator.
    xxxi. The initials FCCU mean or refer to fluid catalytic
cracking unit.
    xxxii. The initials FGD mean or refer to flue gas
desulfurization.
    xxxiii. The initials FGR mean or refer to flue gas
recirculation.
    xxxiv. The initials FIP mean or refer to Federal Implementation
Plan.
    xxxv. The initials FLMs mean or refer to Federal Land Managers.
    xxxvi. The initials HAR mean or refer to hydrated ash
reinjection.
    xxxvii. The initials HDSCR mean or refer to high-dust selective
catalytic reduction.
    xxxviii. The initials HC mean or refer to hydrocarbons.
    xxxix. The initials IMPROVE mean or refer to Interagency
Monitoring of Protected Visual Environments monitoring network.
    xl. The initials IPM mean or refer to Integrated Planning Model.
    xli. The initials LDSCR mean or refer to low-dust selective
catalytic reduction.
    xlii. The initials LEA mean or refer to low excess air.
    xliii. The initials LNBs mean or refer to low NOX
burners.
    xliv. The initials LSD mean or refer to lime spray drying.
    xlv. The initials LSFO mean or refer to limestone forced
oxidation.
    xlvi. The initials LTS mean or refer to Long-Term Strategy.
    xlvii. The initials MDEQ mean or refer to Montana's Department
of Environmental Quality.
    xlviii. The initials MDF mean or refer to medium density
fiberboard.
    xlix. The initials MISO mean or refer to Midwest Independent
Transmission System Operator.
    l. The initials MDU mean or refer to Montana-Dakota Utilities
Company.
    li. The initials MKF mean or refer to mid-kiln firing of solid
fuel.
    lii. The words Montana and State mean the State of Montana.
    liii. The initials MSCC mean or refer to Montana Sulphur and
Chemical Company.
    liv. The initials NEI mean or refer to National Emission
Inventory.
    lv. The initials NESHAP mean or refer to National Emission
Standards for Hazardous Air Pollutants.
    lvi. The initials NH3 mean or refer to ammonia.
    lvii. The initials NOX mean or refer to nitrogen
oxides.
    lviii. The initials NP mean or refer to National Park.
    lix. The initials NSCR mean or refer to non-selective catalytic
reduction.
    lx. The initials NSPS mean or refer to New Source Performance
Standards.
    lxi. The initials NWR mean or refer to National Wildlife
Reserve.
    lxii. The initials OC mean or refer to organic carbon.
    lxiii. The initials OFA mean or refer to overfire air.
    lxiv. The initials PC mean or refer to pulverized coal.
    lxv. The initials PH/PC mean or refer to preheater/precalciner.
    lxvi. The initials PM mean or refer to particulate matter.
    lxvii. The initials PM2.5 mean or refer to
particulate matter with an aerodynamic diameter of less than 2.5
micrometers (fine particulate matter).

    lxviii. The initials PM10 mean or refer to
particulate matter with an aerodynamic diameter of less than 10
micrometers (coarse particulate matter).
    lxix. The initials PMCD mean or refer to particulate matter
control device.
    lxx. The initials ppm mean or refer to parts per million.
    lxxi. The initials PRB mean or refer to Powder River Basin.
    lxxii. The initials PSAT mean or refer to Particulate Matter
Source Apportionment Technology.
    lxxiii. The initials PSD mean or refer to Prevention of
Significant Deterioration.
    lxxiv. The initials RAVI mean or refer to Reasonably
Attributable Visibility Impairment.
    lxxv. The initials RICE mean or refer to Reciprocating Internal
Combustion Engines.
    lxxvi. The initials RMC mean or refer to Regional Modeling
Center.
    lxxvii. The initials ROFA mean or refer to rotating opposed fire
air.
    lxxviii. The initials RP mean or refer to Reasonable Progress.
    lxxix. The initials RPG or RPGs mean or refer to Reasonable
Progress Goal(s).
    lxxx. The initials RPOs mean or refer to regional planning
organizations.
    lxxxi. The initials RRI mean or refer to rich reagent injection.
    lxxxii. The initials RSCR mean or refer to regenerative
selective catalytic reduction.
    lxxxiii. The initials SCOT mean or refer to Shell Claus Off-Gas
Treatment.
    lxxxiv. The initials SCR mean or refer to selective catalytic
reduction.
    lxxxv. The initials SDA mean or refer to spray dryer absorbers.
    lxxxvi. The initials SIP mean or refer to State Implementation
Plan.
    lxxxvii. The initials SMOKE mean or refer to Sparse Matrix
Operator Kernel Emissions.
    lxxxviii. The initials SNCR mean or refer to selective non-
catalytic reduction.
    lxxxix. The initials SO2 mean or refer to sulfur
dioxide.
    xc. The initials SOFA mean or refer to separated overfire air.
    xci. The initials SRU mean or refer to sulfur recovery unit.
    xcii. The initials TESCR mean or refer to tail-end selective
catalytic reduction.
    xciii. The initials TCEQ mean or refer to Texas Commission on
Environmental Quality.
    xciv. The initials tpy mean tons per year.
    xcv. The initials TSD mean or refer to Technical Support
Document.
    xcvi. The initials URP mean or refer to Uniform Rate of
Progress.
    xcvii. The initials VOC mean or refer to volatile organic
compounds.
    xcviii. The initials WA mean or refer to Wilderness Area.
    xcic. The initials WEP mean or refer to Weighted Emissions
Potential.
    c. The initials WRAP mean or refer to the Western Regional Air
Partnership.
    ci. The initials YELP mean or refer to Yellowstone Energy
Limited Partnership.

I. General Information

    The public hearings will provide interested parties the opportunity
to present information and opinions to EPA concerning our proposal.
Interested parties may also submit written comments, as discussed in
the proposal. Written statements and supporting information submitted
during the comment period will be considered with the same weight as
any oral comments and supporting information presented at the public
hearing. We will not respond to comments during the public hearing.
When we publish our final action, we will provide written responses to
all oral and written comments received on our proposal.
    At the public hearing, the hearing officer may limit the time
available for each commenter to address the proposal to 5 minutes or
less if the hearing officer determines it to be appropriate. We will
not be providing equipment for commenters to show overhead slides or
make computerized slide presentations. Any person may provide written
or oral comments and data pertaining to our proposal at the public
hearing. Verbatim transcripts, in English, of the hearing and written
statements will be included in the rulemaking docket.

A. What should I consider as I prepare my comments for EPA?

    1. Submitting CBI. Do not submit CBI to EPA through http://www.regulations.gov or email. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as
CBI and then identify electronically within the disk or CD ROM the
specific information that is claimed as CBI. In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
    2. Tips for Preparing Your Comments. When submitting comments,
remember to:
    a. Identify the rulemaking by docket number and other identifying
information (subject heading, Federal Register date and page number).
    b. Follow directions--The agency may ask you to respond to specific
questions or organize comments by referencing a Code of Federal
Regulations (CFR) part or section number.
    c. Explain why you agree or disagree; suggest alternatives and
substitute language for your requested changes.
    d. Describe any assumptions and provide any technical information
and/or data that you used.
    e. If you estimate potential costs or burdens, explain how you
arrived at your estimate in sufficient detail to allow for it to be
reproduced.
    f. Provide specific examples to illustrate your concerns, and
suggest alternatives.
    g. Explain your views as clearly as possible, avoiding the use of
profanity or personal threats.
    h. Make sure to submit your comments by the comment period deadline
identified.

II. What action is EPA proposing to take?

    EPA is proposing a FIP for the State of Montana (State) to address
regional haze. In so doing, EPA is proposing to determine that the
federal plan along with the change to Montana's visibility plan,
submitted on February 17, 2012, that requires BACT as the visibility
control measure for open burning satisfy the requirements of 40 CFR
51.308.

III. Background

A. Regional Haze

    Regional haze is visibility impairment that is produced by a
multitude of sources and activities which are located across a broad
geographic area and emit fine particulates (PM2.5) (e.g.,
sulfates, nitrates, organic carbon (OC), elemental carbon (EC), and
soil dust), and their precursors (e.g., sulfur dioxide
(SO2), nitrogen oxides (NOX), and in some cases,
ammonia (NH3) and volatile organic compounds (VOC)). Fine
particle precursors react in the atmosphere to form PM2.5,
which impairs visibility by scattering and absorbing light. Visibility
impairment reduces the clarity, color, and visible distance that one
can see. PM2.5 can also cause serious health effects and
mortality in humans and contributes to environmental effects such as
acid deposition and eutrophication.
    Data from the existing visibility monitoring network, the
``Interagency Monitoring of Protected Visual Environments'' (IMPROVE)
monitoring network, show that visibility impairment caused by air
pollution occurs virtually all the time at most national park (NP) and
wilderness areas (WA). The average visual range \1\ in many Class I
areas (i.e., NPs and memorial parks, WA, and international parks
meeting certain size criteria) in the western United States is 100-150

kilometers, or about one-half to two-thirds of the visual range that
would exist without anthropogenic air pollution. In most of the eastern
Class I areas of the United States, the average visual range is less
than 30 kilometers, or about one-fifth of the visual range that would
exist under estimated natural conditions. 64 FR 35715 (July 1, 1999).
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    \1\ Visual range is the greatest distance, in kilometers or
miles, at which a dark object can be viewed against the sky.
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B. Requirements of the CAA and EPA's Regional Haze Rule

    In section 169A of the 1977 Amendments to the CAA, 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,
impairment of visibility in mandatory Class I Federal areas \2\ which
impairment results from manmade air pollution.'' On December 2, 1980,
EPA promulgated regulations to address visibility impairment in Class I
areas that is ``reasonably attributable'' to a single source or small
group of sources, i.e., ``reasonably attributable visibility
impairment.'' 45 FR 80084 (December 2, 1980). These regulations
represented the first phase in addressing visibility impairment. 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 impairment were
improved.
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    \2\ Areas 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 of Interior, promulgated a list of 156 areas
where visibility is identified as an important value. 44 FR 69122
(November 30, 1979). The extent of a mandatory Class I area includes
subsequent changes in boundaries, such as park expansions. 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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    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 35714 (July 1, 1999), codified at 40 CFR part 51, subpart
P. The Regional Haze Rule revised the existing visibility regulations
to integrate into the regulation provisions addressing regional haze
impairment and established a comprehensive visibility protection
program 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 of the main elements of the
regional haze requirements are summarized in this section of this
preamble. The requirement to submit a regional haze SIP applies to all
50 states, the District of Columbia and the Virgin Islands.\3\ 40 CFR
51.308(b) requires states to submit the first implementation plan
addressing regional haze visibility impairment no later than December
17, 2007.\4\
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    \3\ Albuquerque/Bernalillo County in New Mexico must also submit
a regional haze SIP to completely satisfy the requirements of
section 110(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).
    \4\ EPA's regional haze regulations require subsequent updates
to the regional haze SIPs. 40 CFR 51.308(g)-(i).
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    Few states submitted a Regional Haze SIP prior to the December 17,
2007 deadline, and on January 15, 2009, EPA found that 37 states,
including Montana and the District of Columbia, and the Virgin Islands,
had failed to submit SIPs addressing the regional haze requirements. 74
FR 2392 (January 15, 2009). Once EPA has found that a state has failed
to make a required submission, EPA is required to promulgate a FIP
within two years unless the state submits a SIP and the Agency approves
it within the two year period. CAA Sec.  110(c)(1).

C. Roles of Agencies in Addressing Regional Haze

    Successful implementation of the regional haze program will require
long-term 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 impairment in Class I areas, states, or the EPA when
implementing a FIP, need to develop strategies in coordination with one
another, taking into account the effect of emissions from one
jurisdiction on the air quality in another.
    Because the pollutants that lead to regional haze can originate
from sources located across broad geographic areas, EPA has encouraged
the states and tribes across the United States to address visibility
impairment from a regional perspective. Five regional planning
organizations (RPOs) were developed to address regional haze and
related issues. The RPOs first evaluated technical information to
better understand how their states and tribes impact Class I areas
across the country, and then pursued the development of regional
strategies to reduce emissions of particulate matter (PM) and other
pollutants leading to regional haze.
    The Western Regional Air Partnership (WRAP) RPO is a collaborative
effort of state governments, tribal governments, and various federal
agencies established to initiate and coordinate activities associated
with the management of regional haze, visibility and other air quality
issues in the western United States. WRAP member State governments
include: Alaska, Arizona, California, Colorado, Idaho, Montana, New
Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and
Wyoming. Tribal members include Campo Band of Kumeyaay Indians,
Confederated Salish and Kootenai Tribes, Cortina Indian Rancheria, Hopi
Tribe, Hualapai Nation of the Grand Canyon, Native Village of Shungnak,
Nez Perce Tribe, Northern Cheyenne Tribe, Pueblo of Acoma, Pueblo of
San Felipe, and Shoshone-Bannock Tribes of Fort Hall.

IV. Requirements for a Regional Haze FIP

    The following is a summary of the requirements of the Regional Haze
Rule. See 40 CFR 51.308 for further detail regarding the requirements
of the rule.

A. The CAA and the Regional Haze Rule

    Regional haze FIPs must assure Reasonable Progress towards the
national goal of achieving natural visibility conditions in Class I
areas. Section 169A of the CAA and EPA's implementing regulations
require states, or EPA when implementing a FIP, to establish long-term
strategies for making Reasonable Progress toward meeting this goal. The
FIP 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 for the purpose of eliminating or reducing
visibility impairment. The specific regional haze FIP requirements are
discussed in further detail below.

B. EPA's Authority To Promulgate a FIP

    On June 19, 2006, Montana submitted a letter to us signifying that
the State would be discontinuing its efforts to revise the visibility
control plan that would have incorporated provisions of

the Regional Haze Rule.\5\ The State acknowledged with this letter that
EPA would make a finding of failure to submit and thus promulgate
additional federal rules to address the requirements of the Regional
Haze Rule, including BART. In response to the State's decision EPA made
a finding of SIP inadequacy on January 15, 2009 (74 FR 2392),
determining that Montana failed to submit a SIP that addressed any of
the required regional haze SIP elements of 40 CFR 51.308.
---------------------------------------------------------------------------

    \5\ Letter from Richard H. Opper, Director Montana Department of
Environmental Quality (further referred to as MDEQ) to Laurel
Dygowski, EPA Region Air Program, June 19, 2006.
---------------------------------------------------------------------------

    Under section 110(c) of the Act, whenever we find that a State has
failed to make a required submission we are required to promulgate a
FIP. Specifically, section 110(c) provides:
    ``(1) The Administrator shall promulgate a Federal implementation
plan at any time within 2 years after the Administrator--
    (A) finds that a State has failed to make a required submission or
finds that the plan or plan revision submitted by the State does not
satisfy the minimum criteria established under [section 110(k)(1)(A)],
or
    (B) disapproves a State implementation plan submission in whole or
in part, unless the State corrects the deficiency, and the
Administrator approves the plan or plan revision, before the
Administrator promulgates such Federal implementation plan.''
    Section 302(y) defines the term ``Federal implementation plan'' in
pertinent part, as:
    ``[A] plan (or portion thereof) promulgated by the Administrator to
fill all or a portion of a gap or otherwise correct all or a portion of
an inadequacy in a State implementation plan, and which includes
enforceable emission limitations or other control measures, means or
techniques (including economic incentives, such as marketable permits
or auctions or emissions allowances) * * *.''
    Thus, because the State withdrew their efforts to revise the
visibility control plan that would have incorporated provisions of the
Regional Haze Rule and we determined the State failed to submit the
SIP, we are required to promulgate a FIP.

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

    The Regional Haze Rule establishes the deciview as the principal
metric or unit for expressing visibility. See 70 FR 39104, 39118 (July
6, 2005). This visibility metric expresses uniform changes in the
degree of haze in terms of common increments across the entire range of
visibility conditions, from pristine to extremely hazy conditions.
Visibility expressed in deciviews is determined by using air quality
measurements to estimate light extinction and then transforming the
value of light extinction using a logarithm function. The deciview is a
more useful measure for tracking progress in improving visibility than
light extinction itself 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\
---------------------------------------------------------------------------

    \6\ The preamble to the Regional Haze Rule provides additional
details about the deciview. 64 FR 35714, 35725 (July 1, 1999).
---------------------------------------------------------------------------

    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 FIPs must contain measures
that ensure ``reasonable progress'' toward the national goal of
preventing and remedying visibility impairment in Class I areas caused
by anthropogenic air pollution by reducing anthropogenic emissions that
cause regional haze. The national goal is a return to natural
conditions, i.e., anthropogenic sources of air pollution would no
longer impair visibility in Class I areas.
    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, or EPA
when implementing a FIP, 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
Regional Haze Rule requires states, or EPA when implementing a FIP, to
determine the degree of impairment (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, or EPA if implementing a FIP, 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. We have provided guidance regarding how to
calculate baseline, natural and current visibility conditions.\7\
---------------------------------------------------------------------------

    \7\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, September 2003, EPA-454/B-03-005, available
at http://www.epa.gov/ttncaaa1/t1/memoranda/RegionalHaze_envcurhr_gd.pdf, (hereinafter referred to as ``our 2003 Natural Visibility
Guidance''); and Guidance for Tracking Progress Under the Regional
Haze Rule, (September 2003, EPA-454/B-03-004, available at http://www.epa.gov/ttncaaa1/t1/memoranda/rh_tpurhr_gd.pdf, (hereinafter
referred to as our ``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. If a state does not submit
this SIP, EPA will implement a FIP to cover this requirement. Baseline
visibility conditions represent the degree of visibility impairment for
the 20% least impaired days and 20% most impaired days for each
calendar year from 2000 to 2004. Using monitoring data for 2000 through
2004, states, or EPA if implementing a FIP, are required to calculate
the average degree of visibility impairment for each Class I area,
based on the average of annual values over the five-year period. The
comparison of initial baseline visibility conditions to natural
visibility conditions indicates the amount of improvement 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 to 2004 baseline period is
considered the time from which improvement in visibility is measured.

D. Determination of Reasonable Progress Goals (RPGs)

    The vehicle for ensuring continuing progress toward achieving the
natural visibility goal is the submission of a series of regional haze
SIPs from the states that establish two RPGs (i.e., two distinct goals,
one for the ``best'' and one for the ``worst'' days) for every Class I
area for each (approximately) 10-year implementation period. See 40 CFR
51.308(d), (f). However, if a state does not submit a SIP for any of
these requirements, then EPA shall implement a FIP. The Regional Haze
Rule does not mandate specific milestones or rates of progress, but
instead requires EPA to establish goals that provide for ``reasonable
progress'' towards achieving natural (i.e., ``background'') visibility
conditions. In setting RPGs, EPA must provide for an improvement in
visibility for the most

impaired days over the (approximately) 10-year period of the FIP, and
ensure no degradation in visibility for the least impaired days over
the same period. Id.
    In establishing RPGs, states, or EPA if implementing a FIP, are
required to consider the following factors established in section 169A
of the CAA and in our Regional Haze Rule at 40 CFR 51.308(d)(1)(i)(A):
(1) The costs of compliance; (2) the time necessary for compliance; (3)
the energy and non-air quality environmental impacts of compliance; and
(4) the remaining useful life of any potentially affected sources. EPA
must demonstrate in our FIP, how these factors are considered when
selecting the RPGs for the best and worst days for each applicable
Class I area. In setting the RPGs, EPA must also consider the rate of
progress needed to reach natural visibility conditions by 2064
(referred to as the ``uniform rate of progress'' or the ``glidepath'')
and the emission reduction measures needed to achieve that rate of
progress over the 10-year period of the FIP. Uniform progress towards
achievement of natural conditions by the year 2064 represents a rate of
progress which EPA is to use for analytical comparison to the amount of
progress we expect to achieve. In setting RPGs, EPA must also consult
with potentially ``contributing states,'' i.e., other nearby states
with emission sources that may be affecting visibility impairment at
Montana's Class I areas. 40 CFR 51.308(d)(1)(iv). In determining
whether EPA's goals for visibility improvement provide for Reasonable
Progress toward natural visibility conditions, EPA is required to
evaluate the demonstrations developed through our FIP, pursuant to
paragraphs 40 CFR 51.308(d)(1)(i) and (d)(1)(ii). 40 CFR
51.308(d)(1)(iii).

E. Best Available Retrofit Technology (BART)

    Section 169A of the CAA directs states, or EPA if implementing a
FIP, to evaluate the use of retrofit controls at certain larger, often
uncontrolled, older stationary sources in order to address visibility
impacts from these sources. Specifically, section 169A(b)(2)(A) of the
CAA requires EPA to implement a FIP 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 \8\ built between 1962 and 1977 procure, install,
and operate the ``Best Available Retrofit Technology'' as determined by
EPA. Under the Regional Haze Rule, EPA is directed to conduct BART
determinations for such ``BART-eligible'' 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, EPA
also has 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.
---------------------------------------------------------------------------

    \8\ The set of ``major stationary sources'' potentially subject
to BART is listed in CAA section 169A(g)(7).
---------------------------------------------------------------------------

    On July 6, 2005, EPA published the Guidelines for BART
Determinations Under the Regional Haze Rule at appendix Y to 40 CFR
part 51 (hereinafter referred to as the ``BART Guidelines'') to assist
states, or EPA if implementing a FIP, in determining which of their
sources should be subject to the BART requirements and in determining
appropriate emission limits for each applicable source. 70 FR 39104
(July 6, 2005). In making a BART determination for a fossil fuel-fired
electric generating plant with a total generating capacity in excess of
750 megawatts (MW), EPA must use the approach set forth in the BART
Guidelines. EPA is encouraged, but not required, to follow the BART
Guidelines in making BART determinations for other types of sources.
Regardless of source size or type, EPA must meet the requirements of
the CAA and our regulations for selection of BART, and EPA's BART
analysis and determination must be reasonable in light of the
overarching purpose of the regional haze program.
    The process of establishing BART emission limitations can be
logically broken down into three steps: first, EPA identifies those
sources which meet the definition of ``BART-eligible source'' set forth
in 40 CFR 51.301; \9\ second, EPA determines which of such sources
``emits any air pollutant which may reasonably be anticipated to cause
or contribute to any impairment of visibility in any such area'' (a
source which fits this description is ``subject to BART''); and third,
for each source subject to BART, EPA then identifies the best available
type and level of control for reducing emissions.
---------------------------------------------------------------------------

    \9\ BART-eligible sources are those sources that have the
potential to emit 250 tons or more of a visibility-impairing air
pollutant, were not in operation prior to August 7, 1962, but were
in existence on August 7, 1977, and whose operations fall within one
or more of 26 specifically listed source categories. 40 CFR 51.301.
---------------------------------------------------------------------------

    States, or EPA if implementing a FIP, must address all visibility-
impairing pollutants emitted by a source in the BART determination
process. The most significant visibility impairing pollutants are
SO2, NOX, and PM. EPA has stated that we should
use our best judgment in determining whether VOC or NH3
compounds impair visibility in Class I areas.
    Under the BART Guidelines, states, or EPA if implementing a FIP,
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. EPA must
document this exemption threshold value in the FIP, and must state the
basis for our 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. EPA should consider
the number of emission sources affecting the Class I areas at issue and
the magnitude of the individual sources' impacts. Any exemption
threshold set by EPA should not be higher than 0.5 deciviews. 40 CFR
part 51, appendix Y, section III.A.1.
    A regional haze FIP, must include source-specific BART emission
limits and compliance schedules for each source subject to BART. Once
EPA 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 of the final FIP. CAA section
169(g)(4) and 40 CFR 51.308(e)(1)(iv). In addition to what is required
by the Regional Haze Rule, general SIP, or FIP, requirements mandate
that the SIP, or FIP, must also include all regulatory requirements
related to monitoring, recordkeeping, and reporting for the BART
controls on the source. See CAA section 110(a). As noted above, the
Regional Haze Rule allows EPA to implement an alternative program in
lieu of BART so long as the alternative program can be demonstrated to
achieve greater Reasonable Progress toward the national visibility goal
than would BART.

F. Long-Term Strategy (LTS)

    Consistent with the requirement in section 169A(b) of the CAA that
states, or EPA if implementing a FIP, include in the regional haze SIP,
or FIP, a 10 to 15 year strategy for making Reasonable Progress,
section 51.308(d)(3) of the Regional Haze Rule requires that states, or
EPA if implementing a FIP, include a LTS in the regional haze SIP, or
FIP. The LTS is the compilation of all control measures that will be
used during the implementation period of the FIP to meet applicable
RPGs. The LTS must include ``enforceable emissions limitations,
compliance schedules, and

other measures as necessary to achieve the reasonable progress goals''
for all Class I areas within, or affected by emissions from, the state
of Montana. 40 CFR 51.308(d)(3).
    When a state's emissions are reasonably anticipated to cause or
contribute to visibility impairment in a Class I area located in
another state, the Regional Haze Rule requires the impacted state, or
EPA if implementing a FIP, to coordinate with the contributing states
in order to develop coordinated emissions management strategies. 40 CFR
51.308(d)(3)(i). In such cases, EPA must demonstrate that it has
included in its FIP, all measures necessary to obtain its share of the
emission reductions needed to meet the RPGs for the Class I area. Id.
at (d)(3)(ii). The RPOs have provided forums for significant interstate
consultation, but additional consultations between states, or EPA if
implementing a FIP, may be required to sufficiently address interstate
visibility issues. This is especially true where two states belong to
different RPOs.
    States, or EPA if implementing a FIP, should consider all types of
anthropogenic sources of visibility impairment in developing their LTS,
including stationary, minor, mobile, and area sources. At a minimum,
EPA must describe how each of the following seven factors listed below
are taken into account in developing our LTS: (1) Emission reductions
due to ongoing air pollution control programs, including measures to
address Reasonably Attributable Visibility Impairment; (2) measures to
mitigate the impacts of construction activities; (3) emissions
limitations and schedules for compliance to achieve the RPG; (4) source
retirement and replacement schedules; (5) smoke management techniques
for agricultural and forestry management purposes including plans as
currently exist within the state for these purposes; (6) enforceability
of emissions limitations and control measures; and (7) the anticipated
net effect on visibility due to projected changes in point, area, and
mobile source emissions over the period addressed by the LTS. 40 CFR
51.308(d)(3)(v).

G. Coordinating Regional Haze and Reasonably Attributable Visibility
Impairment (RAVI)

    As part of the Regional Haze Rule, EPA revised 40 CFR 51.306(c)
regarding the LTS for RAVI to require that the RAVI plan must provide
for a periodic review and SIP revision not less frequently than every
three years until the date of submission of the state's first plan
addressing regional haze visibility impairment, which was due December
17, 2007, in accordance with 40 CFR 51.308(b) and (c). On or before
this date, the state must revise its plan to provide for review and
revision of a coordinated LTS for addressing RAVI and regional haze,
and the state must submit the first such coordinated LTS with its first
regional haze SIP. If the state does not revise its plan in the
appropriate amount of time, EPA shall implement a FIP to address this
requirement. Future coordinated LTS's, and periodic progress reports
evaluating progress towards RPGs, must be submitted consistent with the
schedule for SIP submission and periodic progress reports set forth in
40 CFR 51.308(f) and 51.308(g), respectively. The periodic review of a
state's LTS must report on both regional haze and RAVI impairment and
must be submitted to EPA as a SIP revision. However, if the state does
not provide future coordinated LTS and periodic progress reports
towards RPGs then EPA will cover this by implementing a FIP.

H. Monitoring Strategy and Other Implementation Plan Requirements

    Section 51.308(d)(4) of the Regional Haze Rule includes the
requirement for a monitoring strategy for measuring, characterizing,
and reporting of regional haze visibility impairment that is
representative of all mandatory Class I Federal areas within the state.
The strategy must be coordinated with the monitoring strategy required
in section 51.305 for RAVI. Compliance with this requirement may be met
through ``participation'' in the IMPROVE network, i.e., review and use
of monitoring data from the network. The monitoring strategy is due
with the first regional haze SIP, and it must be reviewed every five
(5) years. The monitoring strategy must also provide for additional
monitoring sites if the IMPROVE network is not sufficient to determine
whether RPGs will be met.
    Under section 51.308(d)(4), the SIP must also provide for the
following:
     Procedures for using monitoring data and other information
in a state with mandatory Class I areas to determine the contribution
of emissions from within the state to regional haze visibility
impairment at Class I areas both within and outside the state;
     Procedures for using monitoring data and other information
in a state with no mandatory Class I areas to determine the
contribution of emissions from within the state to regional haze
visibility impairment at Class I areas in other states;
     Reporting of all visibility monitoring data to the
Administrator at least annually for each Class I area in the state, and
where possible, in electronic format;
     Developing a statewide inventory of emissions of
pollutants that are reasonably anticipated to cause or contribute to
visibility impairment in any Class I area. The inventory must include
emissions for a baseline year, emissions for the most recent year for
which data are available, and estimates of future projected emissions.
A state must also make a commitment to update the inventory
periodically; and
     Other elements, including reporting, recordkeeping, and
other measures necessary to assess and report on visibility.
    The Regional Haze Rule requires control strategies to cover an
initial implementation period extending to the year 2018, with a
comprehensive reassessment and revision of those strategies, as
appropriate, every 10 years thereafter. Periodic SIP revisions must
meet the core requirements of section 51.308(d), with the exception of
BART. The requirement to evaluate sources for BART applies only to the
first Regional Haze SIP. Facilities subject to BART must continue to
comply with the BART provisions of section 51.308(e). Periodic SIP
revisions will assure that the statutory requirement of reasonable
progress will continue to be met.

I. Consultation with States and Federal Land Managers (FLMs)

    The Regional Haze Rule requires that states, or EPA if implementing
a FIP, consult with FLMs before adopting and submitting their SIPs, or
FIPs. 40 CFR 51.308(i). EPA must provide FLMs an opportunity for
consultation, in person and at least 60 days prior to holding any
public hearing on the FIP. This consultation must include the
opportunity for the FLMs to discuss their assessment of impairment of
visibility in any Class I area and to offer recommendations on the
development of the RPGs and on the development and implementation of
strategies to address visibility impairment. Further, EPA must include
in its FIP, a description of how it addressed any comments provided by
the FLMs. Finally, a FIP must provide procedures for continuing
consultation between EPA and FLMs regarding EPA's FIP, visibility
protection program, including development and review of FIP revisions,
five-year progress reports, and the implementation of other programs
having the potential to contribute to impairment of visibility in Class
I areas.

V. EPA's Analysis of Montana's Regional Haze

A. Affected Class I Areas

    In accordance with 40 CFR 51.308(d), we have identified 12 Class I
areas within Montana: Anaconda-Pintler WA, Bob Marshall WA, Cabinet
Mountains WA, Gates of the Mountains WA, Glacier NP, Medicine Lake WA,
Mission Mountain WA, Red Rock Lakes WA, Scapegoat WA, Selway-Bitterroot
WA, U.L. Bend WA and Yellowstone NP. EPA is responsible for developing
RPGs for these 12 Class I areas. EPA has also determined that Montana
emissions have or may reasonably be expected to have impacts at Class I
areas in other states including: Badlands WA, Bridger WA, Craters of
the Moon WA, Fitzpatrick WA, Grand Teton NP, Hells Canyon WA, Lostwood
National Wildlife Reserve (NWR), North Absaroka NP, Teton WA, Theodore
Roosevelt NP, Washakie WA and Wind Cave NP. This determination was
based on Particulate Matter Source Apportionment Technology (PSAT) and
Weighted Emissions Potential (WEP) analysis and is further described in
Table 150.
    EPA worked with the appropriate state air quality agency in each of
these states through our involvement with the WRAP. The WRAP is a
collaborative effort of tribal governments, state governments and
various federal agencies to implement the Grand Canyon Visibility
Transport Commission's recommendations and to develop the technical and
policy tools needed by western states and tribes to comply with the
U.S. EPA's regional haze regulations. Assessment of Montana's
contribution to haze in these Class I areas is based on technical
analyses developed by WRAP as discussed in this notice.

B. Baseline Visibility, Natural Visibility, and Uniform Rate of
Progress

    As required by section 51.308(d)(2)(i) of the Regional Haze Rule
and in accordance with our 2003 Natural Visibility Guidance, EPA
calculated baseline/current and natural visibility conditions for the
Montana Class I areas, Anaconda-Pintler WA, Bob Marshall WA, Cabinet
Mountains WA, Gates of the Mountains WA, Glacier NP, Medicine Lake WA,
Mission Mountain WA, Red Rock Lakes WA, Scapegoat WA, Selway-Bitterroot
WA, U.L. Bend WA and Yellowstone NP on the most impaired and least
impaired days, as summarized below (and further described in the
docket).\10\ The natural visibility conditions, baseline visibility
conditions, and visibility impact reductions needed to achieve the
Uniform Rate of Progress (URP) in 2018 for all Montana Class I areas
are presented in Table 1 and further explained in this section.
---------------------------------------------------------------------------

    \10\ Information presented here was taken from the WRAP TSS
(http://vista.cira.colostate.edu/tss/). Some of this information was
printed and is available in the docket in the document titled
Selected Information from the WRAP TSS (``WRAP TSS Information'').

  Table 1--Visibility Impact Reductions Needed Based on Best and Worst Days Baselines, Natural Conditions, and
                            Uniform Rate of Progress Goals for Montana Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                     20% Worst days                          20% Best days
                                 -------------------------------------------------------------------------------
                                                                2018
      Montana class I area         2000-2004     2018 URP    Reduction   2064 Natural   2000-2004   2064 Natural
                                    Baseline       Goal        needed     conditions     Baseline    conditions
                                   (deciview)   (deciview)     (delta     (deciview)    (deciview)   (deciview)
                                                             deciview)
----------------------------------------------------------------------------------------------------------------
Anaconda-Pintler WA.............        13.41        12.02         1.39          7.43         2.58          1.12
Bob Marshall WA.................        14.48        12.91         1.57          7.73         3.85          1.48
Cabinet Mountains WA............        14.09        12.56         1.53          7.52         3.62          1.48
Gates of the Mountains WA.......        11.29        10.15         1.14          6.38         1.71          0.32
Glacier NP......................        22.26        19.21         3.05          9.18         7.22          2.42
Medicine Lake WA................        17.72        15.42         2.30          7.89         7.26          2.96
Mission Mountain WA.............        14.48        12.91         1.57          7.73         3.85          1.48
Red Rock Lakes WA...............        11.76        10.52         1.24          6.44         2.58          0.43
Scapegoat WA....................        14.48        12.91         1.57          7.73         3.85          1.48
Selway-Bitterroot WA............        13.41        12.02         1.39          7.43         2.58          1.12
U.L. Bend WA....................        15.14        13.51         1.63          8.16         4.75          2.45
Yellowstone NP..................        11.76        10.52         1.24          6.44         2.58          0.43
----------------------------------------------------------------------------------------------------------------

1. Estimating Natural Visibility Conditions
    Natural background visibility, as defined in our 2003 Natural
Visibility Guidance, is estimated by calculating the expected light
extinction using default estimates of natural concentrations of fine
particle components adjusted by site-specific estimates of humidity.
This calculation uses the IMPROVE equation, which is a formula for
estimating light extinction from the estimated natural concentrations
of fine particle components (or from components measured by the IMPROVE
monitors). As documented in our 2003 Natural Visibility Guidance, EPA
allows the use of ``refined'' or alternative approaches to this
guidance to estimate the values that characterize the natural
visibility conditions of Class I areas. One alternative approach is to
develop and justify the use of alternative estimates of natural
concentrations of fine particle components. Another alternative is to
use the ``new IMPROVE equation'' that was adopted for use by the
IMPROVE Steering Committee in December 2005 and the Natural Conditions
II algorithm that was finalized in May 2007.\11\ The purpose of this
refinement to the ``old IMPROVE equation'' is to provide more

accurate estimates of the various factors that affect the calculation
of light extinction.
---------------------------------------------------------------------------

    \11\ The IMPROVE program is a cooperative measurement effort
governed by a steering committee composed of representatives from
Federal agencies (including representatives from EPA and the FLMs)
and RPOs. The IMPROVE monitoring program was established in 1985 to
aid the creation of Federal and State implementation plans for the
protection of visibility in Class I areas. One of the objectives of
IMPROVE is to identify chemical species and emission sources
responsible for existing anthropogenic visibility impairment. The
IMPROVE program has also been a key instrument in visibility-related
research, including the advancement of monitoring instrumentation,
analysis techniques, visibility modeling, policy formulation and
source attribution field studies. http://vista.cira.colostate.edu/improve/Publications/GrayLit/gray_literature.htm.
---------------------------------------------------------------------------

    For all 12 Class I Areas in Montana, EPA opted to use WRAP
calculations in which the default estimates for the natural conditions
(see Table 2) were combined with the ``new IMPROVE equation'' and the
Natural Conditions II algorithm (see Table 3). This is an acceptable
approach under our 2003 Natural Visibility Guidance. Table 2 shows the
default natural visibility values for the 20% worst days and 20% best
days.

Table 2--Default Natural Visibility Values for the 20% Best Days and 20%
                               Worst Days
------------------------------------------------------------------------
                                                    20% Worst   20% Best
                   Class I area                        days       days
------------------------------------------------------------------------
Anaconda-Pintler WA...............................       7.28       2.16
Bob Marshall WA...................................       7.36       2.24
Cabinet Mountains WA..............................       7.43       2.31
Gates of the Mountains WA.........................       7.22       2.10
Glacier NP........................................       7.56       2.44
Medicine Lake WA..................................       7.30       2.18
Mission Mountain WA...............................       7.39       2.27
Red Rock Lakes WA.................................       7.14       2.02
Scapegoat WA......................................       7.29       2.17
Selway-Bitterroot WA..............................       7.32       2.20
U.L. Bend WA......................................       7.18       2.06
Yellowstone NP....................................       7.12       2.00
------------------------------------------------------------------------

    EPA also referred to WRAP calculations using the new IMPROVE
equation. Table 3 shows the natural visibility values for each Class I
Area for the 20% worst days and 20% best days using the new IMPROVE
Equation and Natural Conditions II algorithm.

   Table 3--Visibility Values for the 20% Best Days and 20% Worst Days
                     Using the New IMPROVE Equation
------------------------------------------------------------------------
                                                    20% Worst   20% Best
                   Class I area                        days       days
------------------------------------------------------------------------
Anaconda-Pintler WA...............................       7.43       1.12
Bob Marshall WA...................................       7.73       1.48
Cabinet Mountains WA..............................       7.52       1.48
Gates of the Mountains WA.........................       6.38       0.32
Glacier NP........................................       9.18       2.42
Medicine Lake WA..................................       7.89       2.96
Mission Mountain WA...............................       7.73       1.48
Red Rock Lakes WA.................................       6.44       0.43
Scapegoat WA......................................       7.73       1.48
Selway-Bitterroot WA..............................       7.43       1.12
U.L. Bend WA......................................       8.16       2.45
Yellowstone NP....................................       6.44       0.43
------------------------------------------------------------------------

    The new IMPROVE equation takes into account the most recent review
of the science \12\ and accounts for the effect of particle size
distribution on light extinction efficiency of sulfate, nitrate, and
OC. It also adjusts the mass multiplier for OC (particulate organic
matter) by increasing it from 1.4 to 1.8. New terms are added to the
equation to account for light extinction by sea salt and light
absorption by gaseous nitrogen dioxide. Site-specific values are used
for Rayleigh scattering (scattering of light due to atmospheric gases)
to account for the site-specific effects of elevation and temperature.
Separate relative humidity enhancement factors are used for small and
large size distributions of ammonium sulfate and ammonium nitrate and
for sea salt. The terms for the remaining contributors, EC (light-
absorbing carbon), fine soil, and coarse mass terms, do not change
between the original and new IMPROVE equations.
---------------------------------------------------------------------------

    \12\ The science behind the revised IMPROVE equation is
summarized in our technical support document (TSD), in the TSD for
Technical Products Prepared by the WRAP in Support of Western
Regional Haze Plans (``WRAP TSD''), February 28, 2011, and in
numerous published papers. See for example: Hand, J.L., and Malm,
W.C., 2006, Review of the IMPROVE Equation for Estimating Ambient
Light Extinction Coefficients--Final Report. March 2006. Prepared
for IMPROVE, Colorado State University, Cooperative Institute for
Research in the Atmosphere, Fort Collins, Colorado, available at
http://vista.cira.colostate.edu/improve/publications/GrayLit/016_IMPROVEeqReview/IMPROVEeqReview.htm and Pitchford, March 2006,
Natural Haze Levels II: Application of the New IMPROVE Algorithm to
Natural Species Concentrations Estimates. Final Report of the
Natural Haze Levels II Committee to the RPO Monitoring/Data Analysis
Workgroup. September 2006, available at http://vista.cira.colostate.edu/improve/Publications/GrayLit/029_NaturalCondII/naturalhazelevelsIIreport.ppt.
---------------------------------------------------------------------------

2. Estimating Baseline Conditions
    As required by section 51.308(d)(2)(i) of the Regional Haze Rule
and in accordance with our 2003 Natural Visibility Guidance, EPA
calculated baseline visibility conditions for Anaconda-Pintler WA, Bob
Marshall WA, Cabinet Mountains WA, Gates of the Mountains WA, Glacier
NP, Medicine Lake WA, Mission Mountain WA, Red Rock Lakes WA, Scapegoat
WA, Selway-Bitterroot WA, U.L. Bend WA and Yellowstone NP. The baseline
condition calculation begins with the calculation of light extinction,
using the IMPROVE equation. The IMPROVE equation sums the light
extinction \13\ resulting from individual pollutants, such as sulfates
and nitrates. As with the natural visibility conditions calculation,
EPA chose to use the new IMPROVE equation.
---------------------------------------------------------------------------

    \13\ The amount of light lost as it travels over one million
meters. The haze index, in units of deciviews, is calculated
directly from the total light extinction, bext expressed
in inverse megameters (Mm-1), as follows: HI = 10
ln(bext/10).
---------------------------------------------------------------------------

    The period for establishing baseline visibility conditions is 2000
through 2004, and baseline conditions must be calculated using
available monitoring data. 40 CFR 51.308(d)(2). This FIP proposes to
use visibility monitoring data collected by IMPROVE monitors located in
all Montana Class I areas for the years 2000 through 2004 and the
resulting baseline conditions represent an average for 2000 through
2004. Table 4 shows the baseline conditions for each Class I area.

    Table 4--Baseline Conditions on 20% Worst Days and 20% Best Days
------------------------------------------------------------------------
                                                    20% Worst   20% Best
                   Class I area                        days       days
------------------------------------------------------------------------
Anaconda-Pintler WA...............................      13.41       2.58
Bob Marshall WA...................................      14.48       3.85
Cabinet Mountains WA..............................      14.09       3.62
Gates of the Mountains WA.........................      11.29       1.71
Glacier NP........................................      22.26       7.22
Medicine Lake WA..................................      17.72       7.26
Mission Mountain WA...............................      14.48       3.85
Red Rock Lakes WA.................................      11.76       2.58
Scapegoat WA......................................      14.48       3.85
Selway-Bitterroot WA..............................      13.41       2.58
U.L. Bend WA......................................      15.14       4.75
Yellowstone NP....................................      11.76       2.58
------------------------------------------------------------------------

3. Summary of Baseline and Natural Conditions
    To address the requirements of 40 CFR 51.308(d)(2)(iv)(A), EPA also
calculated the number of deciviews by which baseline conditions exceed
natural visibility conditions at each Class I area. Table 5 shows the
number of deciviews by which baseline conditions exceed natural
visibility conditions at each Class I area.

Table 5--Number of Deciviews by Which Baseline Conditions Exceed Natural
                          Visibility Conditions
------------------------------------------------------------------------
                                                    20% Worst   20% Best
                   Class I area                        days       days
------------------------------------------------------------------------
Anaconda-Pintler WA...............................       5.98       1.46
Bob Marshall WA...................................       6.75       2.37
Cabinet Mountains WA..............................       6.57       2.14
Gates of the Mountains WA.........................       4.91       1.39
Glacier NP........................................      13.08        4.8
Medicine Lake WA..................................       9.83        4.3
Mission Mountain WA...............................       6.75       2.37
Red Rock Lakes WA.................................       5.32       2.15
Scapegoat WA......................................       6.75       2.37
Selway-Bitterroot WA..............................       5.98       1.46

U.L. Bend WA......................................       6.98        2.3
Yellowstone NP....................................       5.32       2.15
------------------------------------------------------------------------

4. Uniform Rate of Progress
    In setting the RPGs, EPA reviewed and relied on the WRAP analysis
to analyze and determine the URP needed to reach natural visibility
conditions by the year 2064. In so doing, the analysis compared the
baseline visibility conditions in each Class I area to the natural
visibility conditions in each Class I area (as described above) and
determined the URP needed in order to attain natural visibility
conditions by 2064 in all Class I areas. The analysis constructed the
URP consistent with the requirements of the Regional Haze Rule and
consistent with our 2003 Tracking Progress Guidance by plotting a
straight graphical line from the baseline level of visibility
impairment for 2000 through 2004 to the level of visibility conditions
representing no anthropogenic impairment in 2064 for each Class I area.
The URPs are summarized in Table 6. It is clear from Table 6 that there
is a large range of baseline and natural visibility conditions across
the 12 Class I areas in Montana. The degree of improvement to meet the
URP at these sites varies from, 1.24 deciviews at Yellowstone NP to
3.05 deciviews at Glacier NP.

                                             Table 6--Summary of Uniform Rate of Progress for 20% Worst Days
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Total
                                                                       Baseline      Natural    improvement by      URP        2018 URP   Improvement by
                            Class I area                              conditions    visibility       2064        (deciview/     target         2018
                                                                      (deciview)    (deciview)    (deciview)       year)      (deciview)    (deciview)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Anaconda-Pintler WA................................................         13.41         7.43            5.98         0.10        12.02            1.39
Bob Marshall WA....................................................         14.48         7.73            6.75         0.11        12.91            1.57
Cabinet Mountains WA...............................................         14.09         7.52            6.57         0.11        12.56            1.53
Gates of the Mountains WA..........................................         11.29         6.38            4.91         0.08        10.15            1.14
Glacier NP.........................................................         22.26         9.18           13.08         0.22        19.21            3.05
Medicine Lake WA...................................................         17.72         7.89            9.83         0.16        15.42             2.3
Mission Mountain WA................................................         14.48         7.73            6.75         0.11        12.91            1.57
Red Rock Lakes WA..................................................         11.76         6.44            5.32         0.09        10.52            1.24
Scapegoat WA.......................................................         14.48         7.73            6.75         0.11        12.91            1.57
Selway-Bitterroot WA...............................................         13.41         7.43            5.98         0.10        12.02            1.39
U.L. Bend WA.......................................................         15.14         8.16            6.98         0.12        13.51            1.63
Yellowstone NP.....................................................         11.76         6.44            5.32         0.09        10.52            1.24
--------------------------------------------------------------------------------------------------------------------------------------------------------

5. Contribution Assessment According to IMPROVE Monitoring Data
    The visibility and pollutant contributions on the 20% worst
visibility days for the baseline period (2000-2004) show considerable
variation across the 12 Class I areas in Montana. Table 7 shows average
data from the IMPROVE monitors for 2000 to 2004.\14\ The table shows
light extinction from specific pollutants as well as total extinction,
as determined by the monitoring data. As stated above, this data
provides further detail regarding the considerable variation across the
12 Class I areas in Montana.
---------------------------------------------------------------------------

    \14\ Additional data and information can be found at: http://views.cira.colostate.edu/web/DataFiles/SummaryDataFiles.aspx.

                                       Table 7--Species-Specific Light Extinction Determined From Monitoring Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Organic   Elemental                          Coarse      Total
                    Class I area                       Deciview   Sulfate    Nitrate     carbon     carbon      Soil     Sea salt    matter   extinction
--------------------------------------------------------------------------------------------------------------------------------------------------------
Anaconda-Pintler WA.................................      13.41       4.83       1.46      20.01       2.52       0.94       0.26       2.49       42.52
Bob Marshall WA.....................................      14.48       5.12       1.43      22.29       2.80       1.29       0.03       3.60       46.58
Cabinet Mountains WA................................      14.09       6.48       2.02      16.95       2.79       1.03       0.10       2.81       42.18
Gates of the Mountains WA...........................      11.29       5.41       1.88      11.26       1.82       0.75       0.06       1.68       31.85
Glacier NP..........................................      22.26      11.37       9.36      87.68      11.20       1.40       0.28       5.22      137.50
Medicine Lake WA....................................      17.72      16.96      16.27       9.48       2.34       0.75       0.03       4.46       61.30
Mission Mountains WA................................      14.48       5.12       1.43      22.29       2.80       1.29       0.03       3.60       46.58
Red Rock Lakes WA...................................      11.76       4.26       1.77      13.48       2.48       0.95       0.02       2.58       34.55
Scapegoat WA........................................      14.48       5.12       1.43      22.29       2.80       1.29       0.03       3.60       46.58
Selway-Bitterroot WA................................      13.41       4.83       1.46      20.01       2.52       0.94       0.26       2.49       42.52
U.L. Bend WA........................................      15.14       9.78       8.01      12.76       2.08       0.77       0.01       4.01       48.43
Yellowstone NP......................................      11.76       4.26       1.77      13.48       2.48       0.95       0.02       2.58       34.55
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The poorest visibility on the 20% worst days was at Glacier NP at
22.26 deciviews, while the best visibility was at Gates of the
Mountains WA at 11.26 deciviews. Fire appears to be a major factor
contributing to the spatial differences. The five-year average
contributions in Table 7 indicate that Glacier NP has significantly
higher contributions from organic carbon mass than Gates of the
Mountains WA. The daily monitoring data for Glacier NP shows an episode
of exceptionally high organic carbon mass during August 2003 that
indicates a fire event. This single episode influenced the five-year
average values for Glacier NP.

C. BART Determinations

    BART is an element of EPA's LTS for the first implementation
period. As discussed in more detail in section IV.E of this preamble,
the BART evaluation process consists of three components: (1) An
identification of all the BART-eligible sources; (2) an assessment of
whether those BART-eligible sources are in fact subject to BART; and
(3) a determination of any BART controls. EPA addressed these steps as
follows:
1. BART-Eligible Sources
    The first step of a BART evaluation is to identify all the BART-
eligible sources within the state's boundaries. While Montana did not
submit a SIP, the State did provide some useful information; and as
discussed below, we are proposing it as our conclusion.
    EPA used some information and analyses developed by Montana as
described below.
    Montana identified the following 10 sources to be BART-eligible:
ASARCO LLC East Helena Plant; Ash Grove Cement Company; Cenex Harvest
States Cooperative; Laurel Refinery; PPL Montana, LLC; Colstrip Steam
Electric Station Units 1 and 2; Columbia Falls Aluminum Company, LLC;
ExxonMobil Refining & Supply Company Billings Refinery; Holcim (US),
Inc,; Montana Sulfur & Chemical Company; and Smurfit-Stone Container
Enterprises Inc, Missoula Mill.\15\ Montana originally identified
ASARCO LLC East Helena Plant as BART-eligible; however, the emission
units at the facility have since been demolished. Thus, we are
proposing that the ASARCO LLC East Helena Plant is not BART-
eligible.\16\
---------------------------------------------------------------------------

    \15\ This list can be found in the docket with the title,
Montana BART-Eligible Facility List.
    \16\ Correspondence between ASARCO LLC and EPA can be found in
the docket in the file titled ASARCO Correspondence.
---------------------------------------------------------------------------

    The State identified the BART-eligible sources in Montana by
utilizing the approach set out in the BART Guidelines (70 FR 39158
(July 6, 2005)); \17\ this approach provides three criteria for
identifying BART-eligible sources: (1) One or more emission units at
the facility fit within one of the 26 categories listed in the BART
Guidelines; (2) the emission unit(s) began operation on or after August
6, 1962, and was in existence on August 6, 1977; and (3) potential
emissions of any visibility-impairing pollutant from subject units are
250 tons or more per year. Montana initially screened its records to
identify facilities that could potentially meet the three criteria in
the BART Guidelines (70 FR 39158 (July 6, 2005)). Montana contacted the
sources identified through its screening efforts, through a series of
letters, to obtain or confirm this information.\18\
---------------------------------------------------------------------------

    \17\ The flow charts that Montana used to identify BART-eligible
sources are included in the docket in a file titled Montana BART
Flow Charts.
    \18\ Examples of the letters sent to the Montana facilities are
included in the docket in a file titled Montana Letters.
---------------------------------------------------------------------------

    The WRAP also reviewed facility information to identify BART-
eligible sources. The WRAP used the Preliminary 2002 National Emission
Inventory (NEI) to identify all facilities whose actual emissions
exceed 100 tons per year (tpy) or more of any visibility-impairing
pollutant. The WRAP added sources to this preliminary list if they were
identified by the states or tribes; found in various CAA Title V, U.S.
Department of Energy, and EPA databases; or found in EPA background
documents such as those prepared for New Source Performance Standards
(NSPS), maximum achievable control technology standards, and AP-42
emission factors. The WRAP then considered category, date of
construction, and PTE information to determine eligibility. The results
from this analysis identified facilities as BART-eligible, potentially
BART-eligible, not known, or not BART-eligible.\19\
---------------------------------------------------------------------------

    \19\ The WRAP's work is documented in the document titled,
``Identification of BART-Eligible Sources in the WRAP Region'' dated
April 4, 2005. The ``Master List of Montana Sources Reviewed'' in
this report is a second document from the one that is referred to in
a previous footnote titled, ``Montana BART-Eligible Facility List''.
---------------------------------------------------------------------------

    We have reviewed the ``Master List of Montana Sources Reviewed'' in
the report titled ``Identification of BART Eligible Sources in the WRAP
Region'' dated April 4, 2005. We propose to determine that the
following nine facilities identified as BART-eligible by the State and
the WRAP are BART-eligible: Ash Grove Cement Company; Cenex Harvest
States Cooperative, Laurel Refinery; PPL Montana, LLC, Colstrip Steam
Electric Station Units 1 and 2; Columbia Falls Aluminum Company, LLC;
ExxonMobil Refining & Supply Company Billings Refinery; Holcim (US);
Inc, Montana Sulfur & Chemical Company; and Smurfit-Stone Container
Enterprises Inc, Missoula Mill. We propose to determine that the other
facilities identified in the WRAP's April 4, 2005 list as ``potentially
BART-eligible'', ``not known'', or ``not BART-eligible'' are not BART-
eligible.
    The BART Guidelines require that we address SO2,
NOX, and direct PM (including both coarse particulate matter
(PM10) and PM2.5) emissions as visibility-
impairing pollutants and to exercise our ``best judgment to determine
whether VOC or ammonia emissions from a source are likely to have an
impact on visibility in an area.'' See 70 FR 39160, July 6, 2005. VOCs
and NH3 from point sources are not significant visibility-
impairing pollutants at Montana's Class I areas. Point sources
contribute less than 1% to Montana's inventory for both NH3
and VOC emissions.\20\ As a result, we have determined that the
emissions from these point sources do not merit BART review.
---------------------------------------------------------------------------

    \20\ WRAP TSS Information.
---------------------------------------------------------------------------

    We are proposing that the nine Montana facilities listed in Table 8
are the BART-eligible sources in the State.

                                Table 8--List of BART-Eligible Sources in Montana
----------------------------------------------------------------------------------------------------------------
                                                                  BART Source category
         BART-eligible source                  Location                   (SC)             Nearest class I area
----------------------------------------------------------------------------------------------------------------
1. Ash Grove Cement Company..........  Montana City, western    Portland cement plants.  Gates of the Mountains
                                        Montana.                                          WA 30 km.
2. Cenex Harvest States Cooperatives   Laurel, central Montana  Petroleum refineries...  North Absaroka WA 113
 Laurel Refinery.                                                                         km.
3. PPL Montana, LLC Colstrip Steam     Colstrip, southeastern   Fossil-fuel fired steam  U.L. Bend WA 200 km.
 Electric Station (Unit 1 and Unit 2).  Montana.                 electric plants of
                                                                 more than 250 million
                                                                 BTUs per hour heat
                                                                 input.
4. Columbia Falls Aluminum Company,    Columbia Falls,          Primary aluminum ore     Glacier NP 10 km.
 LLC.                                   northwestern Montana.    reduction plants.
5. ExxonMobil Refinery & Supply        Billings, central        Petroleum refineries...  North Absaroka WA 143
 Company, Billings Refinery.            Montana.                                          km.

6. Holcim (US), Inc..................  Three Forks, western     Portland cement plants.  Yellowstone NP 100 km.
                                        Montana.
7. PPL Montana, LLC--JE Corette Steam  Billings, central        Fossil-fuel fired steam  North Absaroka WA 137
 Electric Station.                      Montana.                 electric plants of       km.
                                                                 more than 250 million
                                                                 BTUs per hour heat
                                                                 input.
8. Montana Sulfur & Chemical Company.  Billings, central        Chemical process plants  North Absaroka WA 143
                                        Montana.                                          km.
9. Smurfit-Stone Container             Missoula, northwestern   Kraft pulp mills and     Selway-Bitterroot WA 32
 Enterprises Inc., Missoula Mill.       Montana.                 fossil fuel boilers of   km.
                                                                 more than 250 million
                                                                 BTUs per hour heat
                                                                 input.
----------------------------------------------------------------------------------------------------------------

2. Sources Subject to BART
    The second step of the BART evaluation is to identify those BART-
eligible sources that may reasonably be anticipated to cause or
contribute to any visibility impairment at any Class I area, i.e.,
those sources that are subject to BART. The BART Guidelines allow us to
consider exempting some BART-eligible sources from further BART review
because they may not reasonably be anticipated to cause or contribute
to any visibility impairment in a Class I area. Consistent with the
BART Guidelines, the WRAP performed dispersion modeling to assess the
extent of each BART-eligible source's contribution to visibility
impairment at surrounding Class I areas and we propose to use that
modeling.
a. Modeling Methodology
    The BART Guidelines provide that we may use the CALPUFF \21\
modeling system or another appropriate model to predict the visibility
impacts from a single source on a Class I area and to, therefore,
determine whether an individual source is anticipated to cause or
contribute to impairment of visibility in Class I areas, i.e., ``is
subject to BART.'' The Guidelines state that we find CALPUFF is the
best regulatory modeling application currently available for predicting
a single source's contribution to visibility impairment (70 FR 39162
(July 6, 2005)).
---------------------------------------------------------------------------

    \21\ Note that our reference to CALPUFF encompasses the entire
CALPUFF modeling system, which includes the CALMET, CALPUFF, and
CALPOST models and other pre and post processors. The different
versions of CALPUFF have corresponding versions of CALMET, CALPOST,
etc. which may not be compatible with previous versions (e.g., the
output from a newer version of CALMET may not be compatible with an
older version of CALPUFF). The different versions of the CALPUFF
modeling system are available from the model developer at http://www.src.com/calpuff/calpuff1.htm.
---------------------------------------------------------------------------

    The BART Guidelines also recommend that a modeling protocol be
developed for making individual source attributions. To determine
whether each BART-eligible source has a significant impact on
visibility, we propose to use the WRAP's modeling that used the CALPUFF
model to estimate daily visibility impacts above estimated natural
conditions at each Class I area within 300 kilometers (km) of any BART-
eligible facility, based on maximum actual 24-hour emissions over a 3-
year period (2000-2002). The modeling followed the WRAP protocol,
CALMET/CALPUFF Protocol for BART Exemption Screening Analysis for Class
I Areas in the Western United States, August 15, 2006, which was
approved by EPA.\22\
---------------------------------------------------------------------------

    \22\ This approval is described on p. 57 of the WRAP TSD. The
WRAP protocol, CALMET/CALPUFF Protocol for BART Exemption Screening
Analysis for Class I Areas in the Western United States, August 15,
2006 can be found in the docket.
---------------------------------------------------------------------------

b. Contribution Threshold
    For the modeling to determine the applicability of BART to single
sources, the BART Guidelines note that the first step is 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. The BART Guidelines state that, ``[a] single source that
is responsible for a 1.0 deciview change or more should be considered
to `cause' visibility impairment.'' 70 FR 39161, July 5, 2005. The BART
Guidelines also state that ``the appropriate threshold for determining
whether a source contributes to visibility impairment may reasonably
differ across states,'' but, ``[a]s a general matter, any threshold
that you use for determining whether a source `contributes' to
visibility impairment should not be higher than 0.5 deciviews.'' Id.
Further, in setting a contribution threshold, states or EPA should
``consider the number of emissions sources affecting the Class I areas
at issue and the magnitude of the individual sources' impacts.'' The
Guidelines affirm that states and EPA are free to use a lower threshold
if they conclude that the location of a large number of BART-eligible
sources in proximity to a Class I area justifies this approach.
    EPA proposes to use a contribution threshold of 0.5 deciviews for
determining which sources are subject to BART. EPA's proposal
considered the numerous sources affecting the Class I areas and the
magnitude of the individual sources impacts. 70 FR 39121, July 6, 2005.
As shown in Table 9, EPA proposes to exempt four of the nine BART-
eligible sources in the State from further review under the BART
requirements. The visibility impacts attributable to each of these
three sources fell well below 0.5 deciviews. Our proposed contribution
threshold captures those sources responsible for most of the total
visibility impacts, while still excluding other sources with very small
impacts. Id.
c. Sources Identified by EPA as BART-Eligible and Subject to BART
    The results of the CALPUFF modeling are summarized in Table 9.
Those facilities listed with demonstrated impacts at all Class I areas
less than 0.5 deciviews are proposed by EPA to not be subject to BART;
those with impacts greater than 0.5 deciviews are proposed by EPA to be
subject to BART.

              Table 9--Individual BART-Eligible Source Visibility Impacts on Montana Class I Areas
----------------------------------------------------------------------------------------------------------------
                                                         Maximum 24-hour
                                                         98th percentile
         Source and unit               Class I area        visibility            Subject to BART or exempt
                                                             impact
                                                           (deciview)
----------------------------------------------------------------------------------------------------------------
1. Ash Grove Cement Company......  Gates of the                     2.52  Subject to BART.
                                    Mountains WA.
                                   Scapegoat WA.......              0.42
                                   Anaconda-Pintler WA              0.09
                                   Bob Marshall WA....              0.39
                                   Mission Mountains                0.06
                                    WA.
                                   Selway-Bitterroot                0.01
                                    WA.
                                   Yellowstone NP.....              0.01
                                   Red Rock Lakes WA..              0.00
                                   Theodore Roosevelt               0.10
                                    NP.
                                   North Absaroka WA..              0.00
                                   Washakie WA........              0.00
                                   Teton WA...........              0.00
2. Cenex Harvest States            North Absaroka WA..              0.04  Exempt.
 Cooperatives, Laurel Refinery.
                                   Yellowstone NP.....              0.02
                                   Washakie WA........              0.03
                                   Teton WA...........              0.01
                                   U.L. Bend WA.......              0.00
                                   Red Rocks Lake WA..              0.00
                                   Gates of the                     0.00
                                    Mountains WA.
3. PPL Montana, LLC Colstrip       U.L. Bend WA.......              2.52  Subject to BART.
 Steam Electric Station Units 1
 and 1.
                                   North Absaroka WA..              1.35
                                   Theodore Roosevelt               2.28
                                    NP.
                                   Washakie WA........              0.69
                                   Yellowstone NP.....              0.86
4. Columbia Falls Aluminum         Glacier NP.........              4.54  Subject to BART.
 Company, LLC.
                                   Bob Marshall WA....              0.11
                                   Mission Mountains                0.08
                                    WA.
                                   Cabinet Mountains                0.12
                                    WA.
                                   Scapegoat WA.......              0.05
                                   Selway-Bitterroot                0.03
                                    WA.
                                   Gates of the                     0.03
                                    Mountains WA.
                                   Anaconda-Pintler WA              0.02
5. ExxonMobil Refinery & Supply    North Absaroka WA..              0.27  Exempt.
 Company, Billings Refinery.\23\
                                   Yellowstone NP.....              0.17
                                   Washakie WA........              0.22
                                   U.L. Bend WA.......              0.23
                                   Teton WA...........              0.10
                                   Gates of the                     0.22
                                    Mountains WA.
                                   Red Rock Lakes WA..              0.09
6. Holcim (US), Inc..............  Yellowstone NP.....              0.52  Subject to BART.
                                   Gates of the                     1.02
                                    Mountains WA.
                                   Anaconda-Pintler WA              0.23
                                   Red Rock Lakes WA..              0.20
                                   Scapegoat WA.......              0.28
                                   North Absaroka WA..              0.43
                                   Bob Marshall WA....              0.28
                                   Washakie WA........              0.11
                                   Theodore Roosevelt               0.08
                                    NP.
                                   Selway-Bitterroot                0.15
                                    WA.
                                   Mission Mountains                0.12
                                    WA.
                                   Glacier NP.........              0.11
7. PPL Montana, LLC-JE Corette     North Absaroka WA..              0.74  Subject to BART.
 Steam Electric Station.
                                   Yellowstone NP.....              0.45
                                   Washakie WA........              0.53
                                   U.L. Bend WA.......              0.91
                                   Teton WA...........              0.22
                                   Gates of the                     0.52
                                    Mountains WA.
                                   Red Rock Lakes WA..              0.21
8. Montana Sulfur & Chemical       North Absaroka WA..              0.22  Exempt.
 Company.
                                   Yellowstone NP.....              0.17
                                   Washakie WA........              0.16
                                   U.L. Bend WA.......              0.30
                                   Teton WA...........              0.08
                                   Gates of the                     0.19
                                    Mountains WA.

                                   Red Rock Lakes WA..              0.09
9. Smurfit-Stone Container         Selway-Bitterroot                0.23  Exempt.
 Enterprises Inc., Missoula Mill.   WA.
                                   Mission Mountains                0.36
                                    WA.
                                   Bob Marshall WA....              0.23
                                   Scapegoat..........              0.21
                                   Anaconda-Pintler WA              0.07
                                   Cabinet Mountains                0.14
                                    WA.
                                   Glacier NP.........              0.19
                                   Gates of the                     0.11
                                    Mountains WA.
                                   Hells Canyon WA....              0.01
                                   Eagles Cap                       0.00
                                    Wilderness.
----------------------------------------------------------------------------------------------------------------
\23\ Exxon Mobil submitted revised modeling dated November 29, 2007 (``Exxon Correspondence''), which is the
  basis for our analysis and is available in the docket.

3. BART Determinations and Federally Enforceable Limits
    The third step of a BART evaluation is to perform the BART
analysis. The BART Guidelines (70 FR 39164 (July 6, 2005)) describe the
BART analysis as consisting of the following five steps:
     Step 1: Identify All Available Retrofit Control
Technologies;
     Step 2: Eliminate Technically Infeasible Options;
     Step 3: Evaluate Control Effectiveness of Remaining
Control Technologies;
     Step 4: Evaluate Impacts and Document the Results; and
     Step 5: Evaluate Visibility Impacts.
    In determining BART, the state, or EPA if implementing a FIP, must
consider the five statutory factors in section 169A of the CAA: (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 of the source; and (5)
the degree of improvement in visibility which may reasonably be
anticipated to result from the use of such technology. See also 40 CFR
51.308(e)(1)(ii)(A). The actual visibility impact analysis occurs
during steps 4 and 5 of the process.
a. Visibility Improvement Modeling
    The fifth factor to consider under EPA's BART Guidelines is the
degree of visibility improvement from the BART control options. See 59
FR 39170 (August 1, 1994). The BART Guidelines recommend using the
CALPUFF air quality dispersion modeling system to estimate the
visibility improvements of alternative control technologies at each
Class I area, typically those within a 300 km radius of the source, and
to compare these to each other and to the impact of the baseline (i.e.,
current) source configuration. The CALPUFF modeling system is comprised
of the CALMET data which is used to pre-process meteorological data;
the CALPUFF model which is used to simulate the conversion of pollutant
emissions to PM2.5 and the transport and fate of
PM2.5; and the CALPOST processor which is used to calculate
visibility impairments at receptors sites.
    The BART Guidelines recommend comparing visibility improvements
between control options using the 98th percentile of 24-hour delta
deciviews, which is equivalent to the facility's 8th highest visibility
impact day. The 98th percentile is recommended rather than the maximum
value to allow for uncertainty in the modeled impacts and to avoid
undue influence from unusual meteorological conditions. The ``delta''
refers to the difference between total deciview impact from the
facility plus natural background, and deciviews of natural background
alone, so ``delta deciviews'' is the estimate of the facility's impact
relative to natural visibility conditions. Visibility is traditionally
described in terms of visual range in kilometers or miles. However, the
visual range scale does not correspond to how people perceive
visibility because how a given increase in visual range is perceived
depends on the starting visibility against which it is compared. Thus,
an increase in visual range may be perceived to be a big improvement
when starting visibility is poor, but a relatively small improvement
when starting visibility is good.
    The ``deciview'' scale is designed to address this problem. It is
linear with respect to perceived visibility changes over its entire
range, and is analogous to the decibel scale for sound. This means that
a given change in deciviews will be perceived as the same amount of
visibility change regardless of the starting visibility. Lower deciview
values represent better visibility and greater visual range, while
increasing deciview values represent increasingly poor visibility. In
the BART Guidelines, EPA determined that ``a 1.0 deciview change or
more from an individual source would cause visibility impairment, and a
change of 0.5 deciviews would contribute to impairment. Generally, 0.5
deciviews is equivalent to a 5% change in perceived visibility and is
the amount of change that will evoke a just noticeable change in most
landscapes.'' \24\ Converting a 5% change in light extinction to a
change in deciviews yields a change of approximately 0.5 deciviews.
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    \24\ BART Guidelines, 70 FR 39120 (July 6, 2005).
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    Under the BART Guidelines, the improved visibility in deciviews
from installing controls is determined by using the CALPUFF air quality
model. CALPUFF, generally, simulates the transport and dispersion of
emissions, and the conversion of SO2 to particulate sulfate
and NOX to particulate nitrate, at a rate dependent on
meteorological conditions and background ozone concentration. These
concentrations are then converted to delta deciviews by the CALPOST
post-processor. The CALPUFF modeling system is available and documented
at EPA's Model Distribution Web page.\25\
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    \25\ EPA's Model Distribution Web page available at: http://www.epa.gov/ttn/scram/dispersion_prefrec.htm#calpuff.
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    The ``delta deciviews'' for control options estimated by the
modeling represents a BART source's impact on visibility at the Class I
areas under

different control scenarios. Each modeled day and location in the Class
I area will have an associated delta deciviews for each control option.
For each day, the model finds the maximum visibility impact of all
locations (i.e., receptors) in the Class I area. From among these daily
values, the BART Guidelines recommend use of the 98th percentile, for
comparing the base case and the effects of various controls.
    As part of the FIP development efforts, EPA determined that CALPUFF
modeling was needed to evaluate emissions scenarios that would be
consistent with the application of controls for Montana sources that
were subject to BART.\26\ EPA contracted with the University of North
Carolina and its subcontractor, Alpine Geophysics, to perform CALPUFF
model simulations for BART sources in Montana. The University of North
Carolina developed a modeling protocol that EPA approved. The protocol
outlines the data sets, models and procedures that were used in the new
CALPUFF modeling for BART sources.\27\ The evaluated Class I areas that
were included in the modeling domain for each BART source are listed in
Table 2 of the modeling protocol. The final report from this modeling
effort is available in the docket.\28\
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    \26\ CALPUFF model simulations had previously been performed for
some MT BART sources for certain emissions scenarios using
meteorological data sets for the period 2001-2003 that were
developed by the WRAP. ``CALMET/CALPUFF Protocol for BART Exemption
Screening Analysis for Class I Areas in the Western United States'',
available at http://pah.cert.ucr.edu/aqm/308/bart/WRAP_RMC_BART_Protocol_Aug15_2006.pdf.
     The WRAP data sets were developed in 2006 using the CALPUFF
model versions and EPA guidance available at that time.
    \27\ ``Modeling Protocol: Montana Regional Haze Federal
Implementation Plan (FIP) Support'', University of North Carolina,
Contract EP-D-07-102, November 14, 2011.
    \28\ Modeling Report: Montana Regional Haze Federal
Implementation Plan (FIP) Support, March 16, 2012.
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    The BART determination guidelines recommend that visibility impacts
should be estimated in deciviews relative to natural background
conditions. CALPOST uses background concentrations of various
pollutants to calculate the natural background visibility impact. EPA
used background concentrations from Table 2-1 of ``Guidance for
Estimating Natural Visibility Conditions Under the Regional Haze
Rule.'' Although the concentration for each pollutant is a single value
for the year, this method allows for monthly variation in its
visibility impact, which changes with relative humidity.
b. BART Five-Factor Determinations and Federally Enforceable Limits
i. Ash Grove Cement
Background
    The Ash Grove Cement (Ash Grove) cement plant near Montana City was
determined to be subject to the BART requirements as explained in
section V.C. As explained in section V.C., the document titled
``Identification of BART Eligible Sources in the WRAP Region'' dated
April 4, 2005 provides more details on the specific emission units at
each facility. Our analysis focuses on the long wet kiln as the primary
source of SO2 and NOX emissions.
    We requested a five factor BART analysis for Ash Grove Cement and
the company submitted that analysis along with updated information.\29\
Ash Grove's five factor BART analysis is contained in the docket for
this action and we have taken it into consideration in our proposed
action.
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    \29\ The following information has been submitted by Ash Grove:
BART Five Factor Analysis Ash Grove Cement Montana City, Montana,
Prepared by Trinity Consultants (``Ash Grove BART Analysis'') (June
2007); Letter to Callie Videtich RE: Ash Grove Cement Montana City
Plant, Response to Comments on Best Available Retrofit Technology
(``Ash Grove Response to Comments''), (February 28, 2008) (note that
no redacted information that was claimed to be CBI by Ash Grove was
used from this submittal); Letter to Callie Videtich RE: Ash Grove
Cement-Montana City Plant, Response to Comments on Best Available
Retrofit Technology (``Ash Grove Additional Response to Comments'')
(May 5, 2008); Email to Laurel Dygowski from Bob Vantuyl RE: Ash
Grove Cement Montana City BART: Cost Analysis for Ash Grove SNCR
(``Ash Grove SNCR Cost'') (December 17, 2008); Email to Laurel
Dygowski from Bob Vantuyl RE: Ash Grove Cement Montana City Low
NOX Burner Cost Effectiveness (``Ash Grove LNB Cost'')
(January 23, 2009); Letter to Vanessa Hinkle from Thomas R. Wood RE:
Substantiation for Confidential Business Information Claim for
Information Submitted for Best Available Retrofit Technology
Analysis (``Ash Grove Additional Information July 2011'') (July 18,
2011); Letter to Vanessa Hinkle from Thomas R. Wood RE: Response to
Request for Additional Information for Montana City BART
Determination (``Ash Grove Additional Information October 2011'')
(October 5, 2011); Email to Vanessa Hinkle from Thomas R. Wood RE:
Ash Grove City Cement Company, Montana City Plant (``Ash Grove
Additional Information November 2011'') (November 7, 2011); Email to
Vanessa Hinkle from Curtis Lesslie RE: DAA Cost Analysis (``Ash
Grove DAA Cost Analysis'') (December 20, 2011); Email to Vanessa
Hinkle from Curtis Lesslie RE: Ash Grove Montana City BART Analysis
Update (``Ash Grove Update January 2012'') (January 19, 2012);
Letter to Vanessa Hinkle from Thomas R. Wood RE: Ash Grove Cement
Company Response to Supplemental Information Request (``Ash Grove
Update March 2012'') (March 9, 2012).
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NOX
Step 1: Identify All Available Technologies
    We identified that the following NOX control
technologies are available for the kiln at Ash Grove: low
NOX burners (LNB), mid-kiln firing of solid fuel (MKF),
cement kiln dust (CKD) insufflation, flue gas recirculation (FGR),
selective noncatalytic reduction (SNCR), and selective catalytic
reduction (SCR).
    LNBs use stepwise or staged combustion and localized exhaust gas
recirculation (i.e., at the flame). Staging of combustion air as
achieved by such burners is an available control technology for
NOX reduction in cement kilns. In the first stage, fuel
combustion is carried out in a high temperature fuel-rich environment
and the combustion is completed in the fuel-lean low temperature second
stage. By controlling the available oxygen and temperature, LNBs
attempt to reduce NOX formation in the flame zone. LNBs have
been used by the cement industry for nearly 30 years and are designed
to reduce flame turbulence, delay fuel/air mixing, and establish fuel-
rich zones for initial combustion. LNBs can be used in combination with
SNCR to achieve even greater emissions reduction.
    MKF is a form of secondary combustion where a portion of the fuel
is fired in a location other than the burning zone. Ash Grove currently
uses a mixture of coal and petroleum coke as the primary fuels for the
kiln. A common fuel used for mid kiln firing is scrap tires. By adding
fuel mid-kiln, MKF changes both the flame temperature and the flame
length. This reduces thermal NOX formation by burning part
of the fuel at a lower temperature by creating reducing conditions at
the mid-kiln fuel injection point which may destroy some of the
NOX formed upstream in the kiln burning zone.
    CKD insufflation is a residual byproduct that can be produced by
any of the four basic types of cement kiln systems. As a means of
recycling usable CKD to the cement pyroprocess, CKD can be injected or
insufflated into the burning zone of the rotary kiln in or near the
main flame. The presence of these cold solids within or in close
proximity to the flame cools the flame and/or the burning zone thereby
reducing the formation of thermal NOX.
    FGR involves the use of oxygen-deficient flue gas from some point
in the process as a substitute for primary air in the main burner pipe
in the rotary kiln.\30\ FGR lowers the peak flame temperature and
develops localized reducing conditions in the burning zone by reducing
the oxygen content of the primary combustion air. The intended

effect is to decrease both thermal and fuel NOX formation in
the rotary kiln.
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    \30\ Ash Grove BART Analysis, p. 5-6.
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    In SNCR systems, a reagent such as NH3 or urea is
injected into the flue gas at a suitable temperature zone, typically in
the range of 1,800 to 2,000 [deg]F and at an appropriate ratio of
reagent to NOX. SNCR system performance depends on
temperature, residence time, turbulence, oxygen content, and other
factors specific to the given gas stream. SNCR can be used in
combination with LNBs to achieve even greater emissions control.
    SCR uses either NH3 or urea in the presence of a metal
based catalyst to selectively reduce NOX emissions. SCR is
used in the electric utility industry to reduce NOX
emissions from boilers and has been used on three cement kilns in
Europe. SCR is capable of reducing NOX emissions by about
80%.
Step 2: Eliminate Technically Infeasible Options
    Ash Grove estimated that approximately 1.3 million tires would be
required to use MKF at the Montana City kiln.\31\ There is not a
consistent supply of scrap tires of this volume that would be available
for the Montana city kiln; therefore, MKF was not considered further.
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    \31\ Ash Grove BART Analysis, p. 5-8.
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    CKD insufflation can be used at some cement kilns, but can be
problematic for others. The cement making process requires a very hot
flame to heat the clinkering raw material to about 2,700 [deg]F in as
short a time as possible.\32\ Because of the increased requirements for
thermal energy in the burning zone when insufflation is employed, and
the expected increase in fuel required, it is not an attractive
technology for wet kiln systems; therefore, CKD insufflation was not
considered further.
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    \32\ Ash Grove BART Analysis, p. 5-6.
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    FGR is used in the electric utility industry, but is not
transferrable to cement kilns. For cement kilns, a hot flame is
required to complete the chemical reactions that form the clinker
minerals from the raw materials. The long/lazy flame that would be
produced by FGR would result in the production of unacceptable quality
clinker . Clinkering reactions must take place in an oxidizing
atmosphere in the burning zone to generate clinker that can be used to
produce acceptable cement. FGR would tend to produce localized or
general reducing conditions that also could detrimentally affect
clinker quality. Adding FGR to a burner that is already designed for
optimum flame shaping and control would distort the thermal profile of
the kiln, such that product quality would be unacceptably compromised.
For these reasons, FGR was not considered further.
    SCR has been used on three kilns in Europe; two are preheater
kilns, and one kiln is a Polysius Lepol technology kiln, which is a
traveling grate preheater kiln. 73 FR 34079 (June 16, 2008). Although
we find that SCR is technically feasible for cement kilns, we have not
analyzed it further because of the uncertainty regarding control
effectiveness and costs. We note that EPA has acknowledged, in the
context of establishing the NSPS for Portland Cement Plants,
substantial uncertainty regarding the control effectiveness and costs
associated with the use of SCR at such plants. See 75 FR 54995
(September 9, 2010). SCR for cement kilns will be re-evaluated in
subsequent reasonable progress (RP) planning periods.
Step 3: Evaluate Control Effectiveness of Remaining Control Technology
    For LNB on Ash Grove's kiln it is appropriate to assume a control
effectiveness of 15%.\33\ For SNCR, in evaluating the technology, a
control effectiveness of 50% is appropriate, and for LNB+SNCR a control
effectiveness of 58% is appropriate.
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    \33\ EPA provided an example of LNB on a long wet kiln with a
control effectiveness of 14% in NOX Control Technologies
for the Cement Industry, Final Report, September 2000, p. 61.
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    The following discussion is an explanation of why we consider 50%
control effectiveness an appropriate estimate for SNCR at long wet
kilns, such as Ash Grove's Montana City kiln. Ash Grove has used SNCR
at similar wet kilns in Midlothian, TX. Emissions data submitted by Ash
Grove to the Texas Commission on Environmental Quality (TCEQ) show that
Ash Grove was able to achieve emission rates in the range of 1.6 to 2.9
lb/ton of clinker from June through August 2008 when using SNCR.\34\
The emissions reports submitted to the TCEQ indicate that Ash Grove had
been using SNCR in 2007 on one of their kilns at Midlothian; however,
since the report doesn't specify the exact timeframe we do not know
whether the 2007 data can be compared to the June through August 2008
data. Because the emission report data submitted to the TCEQ for SNCR
use in 2007 is from an unknown time, we used 2006 emission data from
the same three months as the 2008 data--June through August to assess
the performance of the SNCR.\35\ Table 10 summarizes emission from the
Midlothian kilns using the 2006 and 2008 data.
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    \34\ See the document received from TCEQ available in the
docket: Ash Grove Texas, L.P.--Midlothian Plant 2008 Actual Emission
Rate Calculations--Kilns, Ash Grove Texas, L.P.--Midlothian Plant
2008 Actual Emission Rate calculations--Input Data.
    \35\ See the documents received from TCEQ available in the
docket: Ash Grove Texas, L.P.--Midlothian Plant 2006 Actual Emission
Rate Calculations--Kilns; Ash Grove Texas, L.P.--Midlothian Plant
2006 Actual Emission Rate Calculations--Input Data; Ash Grove Texas,
L.P.--Midlothian Plant 2008 Actual Emission Rate Calculations--
Kilns, Ash Grove Texas, L.P.--Midlothian Plant 2008 Actual Emission
Rate calculations--Input Data.

                                             Table 10--NOX Emissions for 2006 and 2008 for Ash Grove Cement
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       June through August 2006 emission rate (lb/ton      June through August 2008 emission rate (lb/ton
                                                          clinker)                                            clinker)                        Percentage
                                    --------------------------------------------------------------------------------------------------------  reduction
                                         June         July        August      Average        June         July        August      Average        (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kiln 1.............................          5.2          5.0          4.5          4.9          1.7          1.6          2.2          1.8         62.5
Kiln 2.............................          5.0          4.1          3.9          4.4          2.7          2.6          2.8          2.7         37.7
Kiln 3.............................          5.0          4.4          4.2          4.5          2.9          2.6          2.5          2.7         40.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

    When the control effectiveness on all three kilns are averaged
together, a 47.5% reduction was achieved. This is within the range of
control effectiveness values that have been demonstrated at other
kilns.36 37 38
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    \36\ EPA has stated previously that, ``[o]n average, SNCR
achieves approximately a 35 percent reduction in NOX at a
ratio of NH3-to-NOX of about 0.5 and a
reduction of 63 percent at an NH3-to-NOX ratio
of 1.0'' in the Federal Register notice proposing New Source
Performance Standards for Portland cement plants. 73 FR 34078 (June
16, 2008).
    \37\ The Cadence brochures available at: http://cadencerecycling.com/sncr.html and http://www.cadencerecycling.com/Resources/6-PageComplete.pdf state that control efficiencies of up
to 50% can be achieved on long wet kilns. See also Enhancing SNCR
Performance by Induced Mixing, Eric Hansen and Fred Lockwood,
December 2006 available at http://www.cadencerecycling.com/Resources/ICR-Formatted2006.pdf.
    \38\ EPA has stated that, ``there are numerous examples of SNCR
systems achieving emission reductions greater than 50 percent and as
high as 80 percent or more'' in the Federal Register notice
proposing New Source Performance Standards for Portland cement
plants. 73 FR 34079 (June 16, 2008).
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    The concentration of baseline NOX emissions is one
parameter affecting the effectiveness of SNCR. The percentage of
control effectiveness is greater when initial NOX
concentrations are greater. The reaction kinetics decrease as the
concentration of reactants decreases. This is due to thermodynamic
considerations that limit the reduction process at low NOX
concentrations.\39\ The baseline NOX emissions of the Ash
Grove Montana City kiln are significantly higher than those at
Midlothian,\40\ indicating that SNCR on the Montana City kiln would be
expected to achieve even greater control effectiveness when compared to
SNCR on the Midlothian kilns.
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    \39\ EPA's Control Cost Manual (further referred to as CCM)
Sixth Edition, January 2002, EPA 452/B-02-001 p. 1-10. The CCM can