implementation plan an assessment of the number of years it would take
to attain natural conditions if visibility improvement continues at the
rate of progress selected by the State as reasonable.'' We explained in
other responses how we have met those requirements.

I. Comments on Reasonable Progress and Long Term Strategy

    Comment: A commenter stated that based on the WRAP emissions
inventory and air quality modeling, EPA proposed reasonable progress
goals for the 20% worst visibility days for the Montana Class I areas
that are significantly less (16-51%) than the uniform rate of progress
by 2018 and that no Montana Class I area is projected to achieve
natural visibility conditions by 2064. The commenter stated that EPA
projects that, at best, the national goal will not be met for 135 years
at Cabinet Mountains WA and, at worst, for 437 years at the Medicine
Lake WA.
    The commenter stated that the WRAP inventory indicates that point
sources contribute 71% of Montana's total SO2 emissions, yet
point source SO2 emissions in Montana are projected to be
reduced by less than 1% by 2018 (this includes SO2
reductions for BART for Colstrip Units 1 and 2). This change in point
source emissions inventory is considerably less than projected by other
states in Region 8, yet EPA has determined that no additional
SO2 controls are reasonable. The commenter stated that the
WRAP inventory projects that point source NOX emissions
would be reduced by 3% (23,000 tons per year), primarily due to
estimated NOX reductions at Colstrip and that EPA's RP
analyses determined that $282 per ton for NOX reduction at
Devon Energy was cost effective, but NOX controls for all

other facilities were not cost effective. Several controls were below
the cost of $4,659 for SO2 controls at Corette Generating
Station that EPA determined were cost effective for BART. Given the
lack of progress in improving visibility at the Class I areas, EPA
needs to reconsider the cost effectiveness of point source
SO2 and NOX controls.
    Response: We disagree that we should reconsider the cost
effectiveness of point source controls given the lack of progress in
improving visibility at the Class I areas. In determining the measures
necessary to make reasonable progress and in selecting RPGs for
mandatory Class I areas within Montana, we took into account the
following four factors into consideration: costs of compliance; time
necessary for compliance; energy and nonair quality environmental
impacts of compliance; and remaining useful life of any potentially
affected sources. CAA section 169A(g)(1) and 40 CFR 51.308(d)(1)(i)(A).
In the FIP, we demonstrated how these four factors were considered. 40
CFR 51.308(d)(1)(ii) allows for a slower rate of improvement in
visibility than the URP, as long as it is demonstrated that based on
these four factors, it is not reasonable to achieve the URP and that
the selected RPG is reasonable. CAA section 169A(g)(1) and 40 CFR
51.308(d)(1)(i)(A). We respond to specific critiques of our four-factor
analyses elsewhere. To the extent that the commenter is stating that
cost-effectiveness is a fixed value and must be the same whether a
source is subject to BART or RP, we disagree. While the Regional Haze
Rule may allow us to establish a bright line for some of the factors
such as cost-effectiveness and visibility, we are not required to do
so, and have not done so for this action.
    Comment: A commenter stated that oil and gas development has
increased markedly in Montana and neighboring states since the initial
inventory projections provided by the WRAP in 2007 and that EPA should
compare the most recent (Phase III) oil and gas emissions inventory to
that used in the WRAP source apportionment modeling and discuss the
implications of future oil and gas development for visibility at
Montana Class I areas.
    Response: We disagree that we should reevaluate the oil and gas
inventory and discuss the implications of future oil and gas
development for visibility at Montana Class I areas at this time. 40
CFR 51.308(d)(3)(iii) requires us to document the technical basis,
including modeling, monitoring and emissions information on which we
relied. It also requires that we identify the baseline emission
inventory on which our strategies are based. As stated in the proposal,
an emissions inventory for each pollutant was developed by WRAP for
Montana and these inventories were used as inputs to photochemical
modeling that was used to determine the 2018 reasonable progress goal.
77 FR 24047 and 77 FR 24054. 40 CFR 51.308(d)(3)(iii) allows us to rely
on the technical analysis developed by the WRAP, which we have done. We
recognize that emission inventories are dynamic, but at this time it is
not necessary to reevaluate the emission inventories. The Regional Haze
Rule recognizes the need for periodic progress evaluation and requires
progress reports to be submitted every five years. 40 CFR 51.308(g)(4)
requires this report to include, ``[A]an analysis tracking the change
over the past five years in emissions of pollutants contributing to
visibility impairment from all sources and activities within the
state.'' As we explained in our proposal, we will update the statewide
emissions inventories periodically or as necessary and review emissions
information from other states and future emissions projections.
    Comment: MDEQ stated that EPA fails to consider the potential
benefits of the Mercury Air Toxics Standard, the new NOX and
SO2 NAAQS, the forthcoming Boiler MACT, and other rules that
will significantly impact PM2.5, SO2 and
NO2 emissions in its LTS.
    Response: We are sensitive to the challenges of coordinating
compliance with a variety of rules. However, to the extent that MDEQ is
implying that we should have considered the potential benefits of
possible future regulations in our LTS, we disagree. As explained in
our proposed FIP, in order to establish RPGs for the Class I areas in
Montana and to determine the controls needed for the LTS, we followed
the process established in the Regional Haze Rule. The anticipated
visibility improvement in 2018 in all Montana Class I areas accounting
for all existing enforceable federal and state regulations already in
place was considered. 77 FR 24055. With regard to regulations that are
not yet final, we cannot speculate on unknown reductions from
anticipated future federal or state regulations prior to those actions
completing the full regulatory process. None of the Montana sources
have notified us that they will be reducing emissions as a result of
future regulation and we have no basis for estimating what those
emissions may be. Without an enforceable commitment, we cannot assume
that additional reductions will be achieved and we cannot account for
them in our LTS for the Regional Haze FIP. MDEQ has not provided
information to indicate that anything in the Regional Haze FIP will
interfere with the requirements of other regulations. In fact, where
additional controls are required, we would expect that the lower
emission limit would make it easier to comply with future regulations
that also require lower emission limits. We note that the Regional Haze
FIP requires compliance with a specific emission limit and not
necessarily the installation of a specific control technology and that
sources have a full five years after the finalization of the FIP to
comply with any emission limit that would require the installation of
additional control technology.
    Comment: MDEQ suggested that we include all smoke emissions from
open burning and wildfires in the natural background estimates and
recalculate URP and RPGs in each of the State's Class I areas with
these adjusted background levels. MDEQ perceived fire to be the major
contributing factor to the State's visibility impairment, and claimed
that EPA does not make a realistic allowance for smoke contributions to
haze in Montana.
    Response: We agree that industrial facilities are not the only
causes of haze, but we disagree that we should make adjustments to the
inventories, the URP, or the RPGs. Our action considered the many
contributors to haze including industrial facilities. It is not
appropriate to consider open burning as natural background because open
burning is anthropogenic. In our proposal, the emissions inventory
appropriately included natural (non-anthropogenic) wildfire and
anthropogenic sources such as open burning. 77 FR 24093. In developing
a LTS, 40 CFR 51.308(d)(3)(iv) requires us to consider all
anthropogenic sources. More specifically, 40 CFR 51.308(d)(3)(v)(E)
requires the LTS to address smoke management techniques for
agricultural and forestry management techniques. We note that our
proposed action also proposed to approve the revisions to the paragraph
titled ``Smoke Management'' of Title 17, Chapter 8, Subchapter 6, Open
Burning as meeting the requirement in 40 CFR 308(d)(3)(v)(E) because
the plan control emissions from these sources by requiring BACT and
takes into consideration the visibility impacts on mandatory Class I
areas.
    Regardless of the contribution from smoke emissions, 40 CFR
51.308(d)(3)(iv) states, ``The State must identify all anthropogenic
sources of visibility impairment considered by the State in developing
its long-term strategy. The State should consider major and minor
stationary sources,

mobile sources, and area sources.'' In this case, we acted in the place
of Montana and were required to abide by the same requirement to
consider point sources. 40 CFR 51.308(d)(1)(ii) states that, ``if the
State establishes a reasonable progress goal that provides for a slower
rate of improvement in visibility that the rate that would be needed to
attain natural conditions by 2064, the State must demonstrate, based on
the factors in paragraph (d)(1)(i)(A) of this section, that the rate of
progress for the implementation plan to attain natural conditions by
2064 is not reasonable; and that the progress goal adopted by the State
is reasonable. The State must provide the public for review as part of
its implementation plan an assessment of the number of years it would
take to attain natural conditions if visibility improvement continues
at the rate of progress selected by the State as reasonable.'' In this
case, we are acting in the place of Montana. In determining the
measures necessary to make reasonable progress and in selecting RPGs
for mandatory Class I areas within Montana, we evaluated major and
minor point sources according to the four factors required by 40 CFR
51.308 (d)(1)(i)(A) (costs of compliance; time necessary for
compliance; energy and nonair quality environmental impacts of
compliance; and remaining useful life of any potentially affected
sources CAA section 169A(g)(1) and 40 CFR 51.308(d)(1)(i)(A)). In
addition, 40 CFR 51.308(e) requires states to make a BART determination
for each BART-eligible source and in that determination, the state must
consider the five statutory factors.
    The requirements of 40 CFR 51.308(d)(3)(iv) and 40 CFR 51.308(e)
are not dependent on the showing of a certain amount of impairment from
point sources.
    EPA recognized that variability in natural sources of visibility
impairment causes variability in natural haze levels as described in
its ``Guidance for Estimating Natural Visibility Conditions Under the
Regional Haze Rule.'' \54\ The preamble to the BART Guidelines (70 FR
39124) describes an approach used to measure progress toward natural
visibility in Mandatory Class I areas that includes a URP toward
natural conditions for the 20% worst days and no degradation of
visibility on the 20% best days. The use of the 20% worst natural
conditions days in the calculation of the URP takes into consideration
visibility impairment from wild fires, windblown dust and other natural
sources of haze.\55\ 70 FR 39124. The Guidance for Estimating Natural
Visibility Conditions also discusses the use of the 20% best and worst
estimates of natural visibility, provides for revisions to these
estimates as better data becomes available, and discusses possible
approaches for refining natural conditions estimates.\56\
---------------------------------------------------------------------------

    \54\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, U.S. Environmental Protection Agency,
September 2003. http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf">http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf, page 1-1 (Guidance for Estimating Natural
visibility Conditions). The guidance states that, ``Natural
visibility conditions represent the long-term degree of visibility
that is estimated to exist in a given mandatory Federal Class I area
in the absence of human-caused impairment. It is recognized that
natural visibility conditions are not constant, but rather they vary
with changing natural processes (e.g., windblown dust, fire,
volcanic activity, biogenic emissions). Specific natural events can
lead to high short-term concentrations of particulate matter and its
precursors. However, for the purpose of this guidance and
implementation of the regional haze program, natural visibility
conditions represents a long-term average condition analogous to the
5-year average best- and worst-day conditions that are tracked under
the regional haze program.''
    \55\ The preamble further stated that, ``with each subsequent
SIP revision, the estimates of natural conditions for each mandatory
Federal Class I area may be reviewed and revised as appropriate as
the technical basis for estimates of natural conditions improve.''
    \56\ Guidance for Estimating Natural Visibility Conditions, p.3-
1 to 3-4.
---------------------------------------------------------------------------

    For the evaluation of visibility impacts for BART sources, EPA
recommended the use of the natural visibility baseline for the 20% best
days for comparison to the ``cause or contribute'' applicability
thresholds. This estimated baseline is reasonably conservative and
consistent with the goal of attaining natural visibility conditions.
While EPA recognizes that there are natural sources of haze, the use of
the 20% worst natural visibility days is inappropriate for the ``cause
or contribute'' applicability thresholds. For example, if BART source
visibility impacts were evaluated in comparison to days with very poor
natural visibility resulting from nearby wild fires or dust storms, the
BART source impacts would be significantly reduced relative to these
poor natural visibility conditions and would not be protective of
natural visibility on the best 20% days.
    Comment: MDEQ insisted that visibility issues in the Western U.S.
are less stationary source driven than in the Eastern U.S., and that
greater understanding of this difference has developed since Congress
passed the Visibility Protection Act of 1977 and the visibility statute
of the CAA Amendments of 1990.
    Response: To the extent that MDEQ is implying that we are not
required to analyze controls for stationary sources, we disagree. As
explained in other responses, 40 CFR 51.308(d)(3)(iv) requires us to
identify all anthropogenic sources of visibility impairment considered
in developing our long term strategy. It specifically states that we
should consider major and minor stationary sources, mobile sources, and
area sources. Please see the language of 40 CFR 51.308(e) in the
response to the previous comment. The requirements of 40 CFR
51.308(d)(3)(iv) and 40 CFR 51.308(e) are not dependant on the showing
of a certain amount of impairment from point sources.
    Comment: A commenter stated that BART sources such as Corette
should also be considered under reasonable progress and that this would
be consistent with actions EPA has approved in other SIPs. The
commenter stated that EPA is using visibility improvement as measured
by Q over D values as an indirect measure of the benefit of additional
controls under reasonable progress and that it is their understanding
that this is not supported under the Regional Haze Rule as reasonable
progress decisions do not consider visibility improvement. The
commenter requested that control options considered technologically
feasible and cost effective under BART also be considered under
reasonable progress.
    Response: We disagree that BART sources need to be re-evaluated for
the purposes of reasonable progress and that, under the Regional Haze
Rule, reasonable progress determinations may not consider visibility
improvement. Our RP Guidance states, ``Since the BART analysis is
based, in part, on an assessment of many of the same factors that must
be addressed in establishing the RPG, it is reasonable to conclude that
any control requirements imposed in the BART determination also satisfy
the RPG-related requirements for source review in the first RPG
planning period. Hence you may conclude that no additional emissions
controls are necessary for these sources in the first planning
period.'' \57\ The EPA has concluded that, based on the similarity of
many of the same factors for both BART and reasonable progress, that no
additional emissions controls are necessary for BART sources for this
planning period. The commenter has given us no basis to change that
conclusion: Regardless of whether any states have chosen to reevaluate
BART sources for reasonable progress, the

Regional Haze Rule does not require states to do so. With regard to the
statement about using visibility improvement to evaluate additional
controls under reasonable progress, EPA's reasonable progress guidance
states: ``In determining reasonable progress, CAA section 169A(g)(1)
requires States to take into consideration a number of factors.
However, you have flexibility in how to take into consideration these
statutory factors and any other factors that you have determined to be
relevant.'' \58\ The potential reduction in quantity over distance (Q/
D) is a factor that we consider to be relevant because the goal of the
Regional Haze Rule is to improve visibility. The commenter has not
cited any authority supporting the position that visibility
improvements may not be considered in reasonable progress
determinations and therefore has given us no basis to change our use of
this factor.
---------------------------------------------------------------------------

    \57\ Guidance for Setting Reasonable Progress Goals Under the
Regional Haze Program, U.S. Environmental Protection Agency,
(``Reasonable Progress Guidance'') (June 1, 2007) p.4-2--4-3.
    \58\ Reasonable Progress Guidance, p.5-1.
---------------------------------------------------------------------------

    Comment: A commenter stated that the proposal fails to achieve
reasonable progress. The commenter explained that the proposal will
leave visibility in the parks and WAs that are affected by Montana
sources impaired for hundreds of years into the future, nonetheless, we
propose no additional emission reductions from Montana's stationary
sources.
    Response: We disagree that the FIP fails to achieve reasonable
progress. 40 CFR 51.308(d)(1)(ii) states:

    If the State establishes a reasonable progress goal that
provides for a slower rate of improvement in visibility than the
rate that would be needed to attain natural conditions by 2064, the
State must demonstrate, based on the factors in paragraph
(d)(1)(i)(A) of this section, that the rate of progress for the
implementation plan to attain natural conditions by 2064 is not
reasonable; and that the progress goal adopted by the State is
reasonable. The State must provide the public for review as part of
its implementation plan an assessment of the number of years it
would take to attain natural conditions if visibility improvement
continues at the rate of progress selected by the State as
reasonable.

    In determining the measures necessary to make reasonable progress
and in selecting RPGs for mandatory Class I areas within Montana, we
took into account the following four factors into consideration: Costs
of compliance; time necessary for compliance; energy and nonair quality
environmental impacts of compliance; and remaining useful life of any
potentially affected sources. CAA section 169A(g)(1) and 40 CFR
51.308(d)(1)(i)(A). In the FIP, we demonstrated how these four factors
were considered and we also provided, in Table 197, an assessment of
the number of years it would take to attain natural conditions if
visibility improvement continues at the rate of progress that we
selected was reasonable. We respond to specific critiques of our four-
factor analyses elsewhere.
    Comment: A commenter stated that EPA failed to evaluate controls on
all BART-subject sources to meet reasonable progress requirements and
that EPA stated that the BART analyses for these facilities are similar
to the requisite reasonable progress analysis. 77 FR at 24059. The
commenter stated that EPA has ensured that Montana will not achieve
reasonable progress toward natural visibility conditions at Class I
areas affected by Colstrip and Corette and that EPA's approach is
flawed legally and factually. The commenter stated that EPA's approach
fails to distinguish between the purposes of BART and the long-term
strategy under the Regional Haze Rule and that while both are
mechanisms to help states achieve reasonable progress, BART is applied
to a given source--for the purpose of eliminating or reducing
visibility impairment caused or contributed to by that source. 42
U.S.C. section 7491(b)(2)(A). The commenter stated that rather than
focusing on specific sources, the development of a long-term strategy
requires EPA to look at existing visibility impairment--after emissions
reductions due to BART and other strategies are accounted for--and
attribute responsibility for eliminating that impairment among sources
and categories. 40 CFR 51.308(d)(1). The commenter stated that in this
way, the states and EPA maintain flexibility to determine the most
effective and efficient way to eliminate haze pollution when technology
mandates on specified sources have not done the job. The commenter
stated that therefore, measures within a long-term strategy are
required to achieve reasonable progress above and beyond BART and that
by categorically eliminating all BART-subject sources from its
reasonable progress analysis, EPA has failed to meet its obligation to
determine whether emissions reductions from these sources beyond those
required by BART are necessary to achieve the national goal of
eliminating visibility impairment.
    Response: We disagree that BART sources need to be re-evaluated for
the purposes of reasonable progress. Our reasonable progress guidance
states:

    Since the BART analysis is based, in part, on an assessment of
many of the same factors that must be addressed in establishing the
RPG, it is reasonable to conclude that any control requirements
imposed in the BART determination also satisfy the RPG-related
requirements for source review in the first RPG planning period.
Hence you may conclude that no additional emissions controls are
necessary for these sources in the first planning period.\59\
---------------------------------------------------------------------------

    \59\ Reasonable Progress Guidance, p. 4-2--4-3.

    The commenter has given no reason for us to change this position.
    Comment: A commenter stated that EPA's approach essentially
duplicates all of the errors from its BART analysis in its reasonable
progress analysis and that in particular, EPA's incremental visibility
justification for dismissing the most stringent pollution control
technologies is especially inappropriate in the reasonable progress
framework. The commenter stated that incremental visibility improvement
is not included among the four factors to be considered in establishing
reasonable progress measures. 40 CFR 51.308(d)(1)(i)(A). The commenter
stated that if this justification is applied to eliminate the most
effective pollution-reduction measures at every source--especially the
largest and oldest sources that are subject to BART--then Montana may
never make reasonable progress toward achieving natural visibility
conditions.
    Response: We disagree that there are errors in our approach for
BART and reasonable progress for the same reasons we have discussed
previously. Pursuant to 40 CFR 51.308(e)(A) for our BART analyses, we
considered the following five factors in our analysis: The appropriate
level of BART control; the cost of compliance; the energy and nonair
quality environmental impacts; any pollution control equipment in use
at the source; the remaining useful life of the source; and the degree
of improvement which may be reasonably anticipated to result from the
use of such technology. We agree that visibility improvement is not one
of the four factors required by CAA section 169A(g)(1) and 40 CFR
51.308(d)(1)(i)(A), however, it (along with other relevant factors) can
be considered when determining controls that should be required for
reasonable progress. Our reasonable progress guidance states: ``In
determining reasonable progress, CAA section 169A(g)(1) requires States
to take into consideration a number of factors. However, you have
flexibility in how to take into consideration these statutory factors
and any other factors that you have determined to be relevant.'' \60\
For certain potentially affected sources, we considered Q/D and
potential reductions in Q/D, which are relevant to

the goal of the Regional Haze Rule, improving visibility.
---------------------------------------------------------------------------

    \60\ Reasonable Progress Guidance, p. 5-1.
---------------------------------------------------------------------------

    Comments: A commenter stated that EPA failed to require that
Colstrip Units 1 and 2 and Corette make emissions reductions that were
relied upon by the WRAP, EPA, and states neighboring Montana in
establishing reasonable progress goals, and that if EPA fails to revise
its BART determinations for Colstrip Units 1 and 2 and Corette, EPA
must require additional reductions of visibility-impairing pollutants
in its long-term strategy. Another commenter stated that EPA should
have required SCR+SOFA as BART for Colstrip Units 1 and 2 and should
have required SOFA+SCR and a dry scrubber/baghouse for Corette, but
even if EPA were to justify its contrary BART finding in response to
these comments, EPA should have required SCR+SOFA and a dry scrubber/
baghouse at these units as part of its long term strategy. The
commenter explained that where sources within a state contributes to
visibility within another state's Class I area or areas, the state has
an obligation to adopt controls necessary to ensure it achieves its
share of the pollution reductions that are required to meet the
reasonable progress goals set for the subject Class I area.
    Response: We do not agree that we must revise our BART
determinations for Colstrip Units 1 and 2 and Corette. We have stated
in other actions addressing regional haze that a plan that provides for
emission reductions consistent with the assumptions underlying the WRAP
modeling will ensure that a State is not interfering with measures
designed to protect visibility in other states. See e.g. 76 FR 491,
496-497 (Jan. 5, 2011). Similarly, a plan that is consistent with the
assumptions underlying the modeling used to establish RPGs in a state
likely will include the measures necessary to achieve those RPGs.
However, there is no requirement that a SIP (or FIP) adopt the
assumptions underlying the models as enforceable requirements. The air
quality models used to support the regional haze SIPs are extremely
complex, and due to the time consuming nature of performing the
modeling, this work was performed early in the process. The emissions
projections by the RPOs, relied upon in the air quality modeling,
incorporated the best available information at the time from the
states, and utilized the appropriate methods and models to provide a
prediction of emissions from all source categories into the future.
There was an inherent amount of uncertainty in the assumed emissions
from all sources, including emissions from BART-eligible sources, as
the final control decisions by all of the states were not yet complete.
The WRAP used their best estimates of what regional haze SIPs would
achieve as inputs for the modeling. In the end, reductions resulting
from BART determinations based on the statutory factors may differ from
those estimates.
    One relevant requirement cited by the commenter, at 40 CFR
51.308(d)(3)(ii), is that EPA must demonstrate that it has included all
measures necessary to obtain its share of the emission reductions
needed to meet the RPGs for Class I areas where it causes or
contributes to impairment. Montana's neighboring Class I states
originally set the reasonable progress goals in their SIP based on
emission reductions expected to be achieved through application of
presumptive BART and other emission reductions qualified for that
purpose. These neighboring states had the opportunity to comment on the
regional haze FIP, and did not ask for additional emission reductions.
We also note that the RPGs are not enforceable goals. Neighboring
states will have the responsibility to consider whether other
reasonable control measures are appropriate to ensure reasonable
progress during subsequent periodic progress reports and regional haze
SIP revisions as required by 40 CFR 51.308(f)-(h), and may at that time
consider asking EPA for additional emission reductions.
    With respect to Colstrip Units 1 and 2, we note that our FIP
achieves SO2 emissions reductions well beyond those assumed
in the WRAP PRP18b emissions inventory. Specifically, at Units 1 and 2,
assuming operation at 85% of capacity, our FIP achieves reductions of
7,538 tpy of SO2, which is 1,504 tpy better than indicated
by the PRP18b projections. By way of comparison, again assuming
operation at 85% of capacity, our FIP achieves reductions of 6,652 tpy
of NOX for Colstrip Units 1 and 2, which is 1,709 tpy below
that indicated by the PRP18b projections. Because the additional
SO2 reductions are close to the shortfall in NOX
reductions at Colstrip Units 1 and 2, and as SO2 may have a
greater impact than NOX on visibility in Montana, we find
that the overall emissions reductions achieved at Colstrip Units 1 and
2 will result in similar visibility improvement to the emissions
reductions assumed in the WRAP PRP18b projections.
    With respect to Corette, the commenter has overstated the
discrepancy between the emissions associated with our BART
determination and the PRP18b projections, because the commenter has
compared WRAP projections based on annual emissions with emissions
limits that are on a 30-day rolling average. In addition, we note that
we have revised the NOX and SO2 emission limits
for Corette in our FIP to be somewhat more stringent than what we
proposed (and more reflective of actual emissions with existing
controls). Finally, the WRAP projections do not reflect application of
SOFA+SCR or a dry scrubber/baghouse to Corette. Therefore, the
projections do not support the commenter's position that these controls
are required.
    Moreover, there are NOX reductions at other BART sources
that are greater than assumed by WRAP. At Ash Grove and Holcim, the
total reductions from our FIP are significantly more relative to the
PRP18b projections that the WRAP used. In conclusion, our FIP contains
additional emission reductions at BART sources that largely offset any
shortfall at Colstrip Units 1 and 2 and Corette.
    Comment: A commenter stated that our reasonable progress goals are
unreasonable, unsupported, and effectively contrary to the CAA's
requirements that we assure reasonable progress in achieving natural
visibility conditions in Class I areas. The commenter stated that the
proposed RPGs, at a minimum, double the timeframe required to achieve
natural visibility conditions for every Class I area in Montana and
that this is not reasonable. The commenter also stated that the
reasonable progress goals are unreasonable based on the statutory
factors that must be considered by EPA under 42 U.S.C. 7491(g)(1), and
that we provided two reasons for asserting that the reasonable progress
goals are reasonable: That our four factor analyses resulted in limited
opportunities for reasonable progress controls for point sources and
that significant visibility impairment is caused by non-anthropogenic
sources in and outside Montana. The commenter stated that with regard
to the latter issue of non-anthropogenic sources in and outside of
Montana, this is not a statutory factor that EPA is allowed to consider
in establishing RPGs.
    Response: We disagree. It is not necessarily unreasonable for the
RPGs to reflect a longer period of time than the URP. The URP is simply
calculated by dividing the difference between the present visibility
conditions and natural visibility conditions by the number of years
between the baseline and 2064. It assumes a steady rate of progress and
does not take into account the four statutory factors for determining
reasonable progress or any additional factors that warrant
consideration. As a

result, the RPGs, which do reflect consideration of these factors, may
well vary from the URP.
    In determining reasonable progress controls, EPA did consider the
statutory factors for determining reasonable progress set out in 42
U.S.C. 7491(g)(1). To the extent that the commenter argues with our
evaluation of these factors, we respond to specific comments on our
evaluation of these factors elsewhere.
    The commenter is correct that consideration of non-anthropogenic
sources in and outside of Montana is not one of the statutory four
factors that must be considered under 42 U.S.C. 7491(g)(1). However,
EPA's reasonable progress guidance states: ``In determining reasonable
progress, CAA section 169A(g)(1) requires States to take into
consideration a number of factors. However, you have flexibility in how
to take into consideration these statutory factors and any other
factors that you have determined to be relevant.'' \61\ The data
demonstrating that significant visibility impairment is caused by non-
anthropogenic sources in and outside Montana is relevant because it
diminishes the potential improvement that might be realized through
controlling an individual point source within Montana. Therefore, it
was proper for EPA to consider this additional factor.
---------------------------------------------------------------------------

    \61\ Reasonable Progress Guidance, p. 5-1.
---------------------------------------------------------------------------

    Comment: A commenter stated that based on the four factors set
forth under the CAA, it appears that EPA grossly overstated its
assertion that there are only limited opportunities for reasonable
controls for point sources. The commenter stated that this is
particularly the case with regard to NOX emissions from
coal-fired EGUs in Montana. The commenter stated that our proposal
disclosed that for every coal-fired EGU assessed under the four-factor
analysis for determining RPGs, including Colstrip units 3 and 4,
Colstrip Energy, and the Lewis and Clark Station, that cost-effective
SCR control technology could achieve greater NOX emissions
reductions and greater visibility improvements than under our FIP. The
commenter stated that despite this, we rejected SCR as a control option
and ultimately adopted no NOX emission controls for these
four sources. The commenter stated that we also rejected SCR as BART
for Colstrip Units 1 and 2 and the Corette coal-fired EGUs, even though
we found SCR to be a cost-effective and reasonable technology, we
rejected it in favor of weaker controls. The commenter concluded that
we did not show that any of the four factors would mitigate against
additional control and stronger RPGs. The commenter stated that our
assertion that there would be no degradation is not reasonable or
legally justified and that we must establish our reasonable progress
goals based on all coal-fired EGUs using SCR to reduce NOX
emissions.
    Response: We disagree that the four factor analyses for EGUs that
are potentially affected reasonable progress sources mandate the
addition of SCR and that visibility, although not one of the four
statutory factors that are required to be considered, cannot be
considered in determining appropriate controls under reasonable
progress. EPA's reasonable progress guidance states: ``In determining
reasonable progress, CAA section 169A(g)(1) requires States to take
into consideration a number of factors. However, you have flexibility
in how to take into consideration these statutory factors and any other
factors that you have determined to be relevant.'' \62\ For example,
the potential reduction in Q/D is a factor that we consider to be
relevant because the goal of the Regional Haze Rule is to improve
visibility at Class I areas. We note that the commenter, in citing
potential visibility improvement at the facilities mentioned, undercuts
their own argument that the four statutory RP factors by themselves,
without consideration of other factors, demonstrate that EPA ``grossly
overstated'' its conclusion that there are only limited opportunities
for reasonable controls for point sources. Commenter misstated EPA's
conclusions by stating that EPA ``found SCR to be a cost-effective and
reasonable technology'' for the BART EGUs. While we did state that the
cost on a dollars per ton basis was cost-effective, we also explained
that the cost of SOFA + SCR was not justified by the visibility
improvement. 77 FR 24027, 77 FR 24035, and 77 FR 24043. The commenter
misstated the requirements of the Regional Haze Rule. In examining
potentially affected sources for possible controls and setting RPGs,
EPA is not required to ``show that any of the four factors would
mitigate against additional controls and stronger reasonable progress
goals.'' Instead, EPA is required to consider the four statutory
reasonable progress factors. In addition, EPA may consider additional,
relevant factors such as visibility improvement from controls. To the
extent that the comment argues with our determinations for particular
potentially affected sources, we respond to specific criticisms
elsewhere. With regard to commenter's statement that our basis for
determining there would be no degradation on the least impaired days
was unreasonable and not legally justified, we note that the commenter
did not identify any flaw in our data or methodology in deriving Table
198 in the proposal. We therefore disagree with the statement.
---------------------------------------------------------------------------

    \62\ Reasonable Progress Guidance, p.5-1.
---------------------------------------------------------------------------

    Comment: PPL commented that to try to address visibility impairment
only within the universe of point sources subject to potential EPA
regulation within the United States is not reasonable and will not lead
to achievement of Reasonable Progress Goals (RPGs). PPL stated further
that EPA, in conjunction with other federal and state agencies and the
FLMs, should re-evaluate some of the conclusions as to the
uncontrollable nature of several listed significant contributors of
SO2 and NOX. PPL stated that application of the
BART analysis excludes consideration of a number of factors, including
outside domain sources. PPL pointed out that the RPGs in the proposed
FIP do not take into account the contribution of international
emissions to the visibility, and do not address challenges faced by the
state of Montana.
    Response: To the extent that PPL commented that we are addressing
visibility impairment only within the universe of point sources subject
to potential EPA regulation within the United States, that we did not
consider other sources of emissions, we disagree. As explained
elsewhere, our action considered the many contributors to haze
including all anthropogenic sources as required by 40 CFR
51.308(d)(3)(iv) and smoke management techniques for agricultural and
forestry management techniques as required by 40 CFR
51.308(d)(3)(v)(E). In our proposal, the emissions inventory
appropriately included natural (non-anthropogenic) wildfire and
anthropogenic sources such as open burning and international emissions.
We proposed approve the revisions to the smoke management section of
Montana's Visibility SIP as meeting the requirement in 40 CFR
308(d)(3)(v)(E).
    Comment: The NPS commented that EPA used inconsistent criteria in
selecting reasonable progress controls.
    Response: We disagree. As explained in other responses, in
determining the measures necessary to make reasonable progress and in
selecting RPGs for mandatory Class I areas within Montana, we took the
following four factors into consideration: costs of compliance; time
necessary for compliance; energy and nonair quality

environmental impacts of compliance; and remaining useful life of any
potentially affected sources. CAA section 169A(g)(1) and 40 CFR
51.308(d)(1)(i)(A). As also explained in other responses, we also
considered potential visibility improvement in a general sense by
considering the potential reduction in haze causing pollutants and also
the distance from the source to the nearest Class I area. For Colstrip
3 and 4, we also considered visibility modeling results and have
explained the reasoning for that decision in another response.

J. Comments on Colstrip Units 3 and 4

    Comment: Some commenters agreed with EPA's conclusion not to
require additional emissions controls at Colstrip Units 3 and 4.
Commenters asserted that, given the aggressive pollution control
technologies already in place, EPA properly concluded that additional
controls for Reasonable Progress are not appropriate.
    Response: We acknowledge the commenters' support for our decision
not to require additional emission controls on Colstrip Units 3 and 4
in this planning period. Whether additional emission reductions from
reasonable progress sources, including Colstrip Units 3 and 4, are
necessary will be re-evaluated in subsequent planning periods.
    Comment: Various commenters stated that we underestimated the costs
of SNCR for Colstrip Units 3 and 4.
    Response: We disagree that we underestimated the costs of SNCR for
Colstrip Unit 3 and 4. For a further explanation, see our response to
similar comments made in relation to SNCR costs for Colstrip Unit 1 and
2.
    Comment: Commenters stated that they disagree with EPA's cost
analysis for NOX control technologies for Colstrip Units 3
and 4. In particular, commenters stated that we underestimated the
capital costs and cost-effectiveness of these controls. Commenters
referenced cost estimates submitted by PPL in September 2011 and
February 2012, which show much higher capital costs and cost-
effectiveness than those estimated by EPA.
    Response: We disagree. We have rejected PPL's cost estimates for
NOX control options for Colstrip Units 3 and 4 for the same
reasons that we rejected them for Colstrip Units 1 and 2. See previous
responses to comments.
    Comment: NPS stated that EPA modeled baseline visibility impacts at
five Class I areas from Colstrip Units 3 & 4 using 2008-2010 emissions,
while PPL modeled visibility impacts using 2001-2003 emissions. NPS
agreed with the PPL modeling approach because it is consistent with EPA
guidance to use the 2001-2003 pre-control emissions.
    Response: See our response to a similar comment made in regard to
the baseline emissions used for Colstrip Units 1 and 2.
    Comment: NPS stated that after EPA concluded its statutory four-
factor analysis of Colstrip 3 and 4, it created a new, ``Optional
Factor: Modeled Visibility Impacts'' fifth factor, only for Colstrip 3
& 4. NPS further stated that this ``optional'' fifth factor is not
required by statute or regulation, and that EPA only used it on one
reasonable progress source (2 units) and did not explain what criteria
it used to evaluate it.
    Response: As we explained elsewhere, our RP Guidance allows for
consideration of additional factors such as visibility impacts or
benefits. Given the large annual emissions of NOX and
SO2 from Colstrip Units 3 and 4 compared to other reasonable
progress sources, we found that it was reasonable to model the
visibility benefits and consider them when evaluating controls.
    Comment: NPS stated that EPA has not provided criteria used in
making the determination of what ``Costs of Compliance'' are
reasonable, and its determinations vary significantly across Montana
facilities.
    Response: As we have explained elsewhere, while the Regional Haze
Rule and BART Guidelines allow states to establish thresholds for cost-
effectiveness, we are not required to do so and have not done so for
this action. Also, our Reasonable Progress determinations were made
based not just on the cost of compliance, but with consideration of the
four factors along with additional information that was pertinent.
    Comment: EarthJustice stated that EPA must set NOX
emission limits for Colstrip Units 3 and 4 based on SCR to help achieve
reasonable progress. EarthJustice stated that EPA's analysis is skewed
to underestimate the benefits of SCR, both in terms of control
effectiveness and visibility improvement, and overestimates the costs.
EarthJustice made claims regarding our cost analysis for Colstrip Units
3 and 4 that were very similar to the claims they made regarding
Colstrip Units 1 and 2.
    Response: We disagree. Below we address each of EarthJustice's
arguments that support their assertion that SCR must be required for
Colstrip Units 3 and 4.
    Comment: EarthJustice stated that EPA underestimated the control
effectiveness of SCR.
    Response: See our response to similar comment made by EarthJustice
in regard to Colstrip Units 1 and 2.
    Comment: EarthJustice stated that EPA overestimated the cost of
SCR.
    Response: See our response to similar comment made by EarthJustice
in regard to Colstrip Units 1 and 2.
    Comment: EarthJustice claimed that the visibility benefit of SCR on
Units 3 and 4 is substantial and therefore SCR should be required.
EarthJustice noted that EPA modeled visibility benefits of SNCR and SCR
and found a visibility benefit of 0.273 dv per unit from application of
SCR. EarthJustice stated that application of SCR at both units would
approximately halve the units' emissions of visibility impairing
pollutants and would reduce the number of days of visibility impairment
at Theodore Roosevelt NP to just 2 days and would eliminate visibility
impairment caused by Units 3 and 4 at four other Class I areas.
EarthJustice stated that, in light of this, we lacked a basis for our
determination to not impose SCR at Colstrip Units 3 and 4. EarthJustice
noted that, in North Dakota, we imposed LNB on two units at Antelope
Valley Station based on a combined visibility benefit of 0.39 deciview,
which we stated was significant even on a unit-by-unit basis of 0.2
deciview.
    Response: We disagree that SCR should be required based solely on
the modeled visibility benefits. As we explained in our proposal, we
considered the four factors and the modeled visibility benefits of
controls and determined that no additional controls should be required
for this planning period. 77 FR 24066. Also, we stated that
specifically, for SCR, the modeled visibility benefits (0.273 deciview
and 0.260 deciview) were not sufficient for us to consider it
reasonable to impose SCR in this planning period. 77 FR 24066. In
making this determination, we noted that SCR was the more expensive
option ($4,574/ton at Unit 3 and $4,607/ton at Unit 4). The cost of
compliance is one of the four statutory factors, and EarthJustice has
not provided a reason why it should be ignored. For the same reason, we
reject the comparison with our North Dakota action. There, the cost-
effectiveness of LNB at Antelope Valley Station was $586/ton for Unit 1
and $661/ton at Unit 2. 76 FR 58631. We explicitly considered these
costs in making our determination to impose LNB. Here, the cost-
effectiveness of SCR at Colstrip Units 3 and 4 is far above the

cost-effectiveness of LNB at Antelope Valley Units 1 and 2. Thus, the
comparison gives us no basis to change our determination that SCR
should not be required in this planning period.
    Comment: EarthJustice stated that EPA should set more stringent
SO2 emission limits at Colstrip Units 3 and 4 to help
achieve reasonable progress. EarthJustice stated that EPA incorrectly
found that no additional upgrades are feasible and that 98%
SO2 removal to meet an SO2 emission limit of 0.05
lb/MMBtu at Units 3 and 4, which is readily achievable at little
expense using MEL.
    Response: EarthJustice cites a 1984 paper presented at the American
Power Conference to support their argument of a lower emission rate.
Colstrip 3 had only started operation in 1984 and Colstrip 4 did not
commence operation until 1986,\63\ the data cited by EarthJustice
cannot be more than short-term tests of Unit 3 that are not
representative of longer term performance. Annual emissions from 1985
and 1990 emissions from CAMD can be found in the docket. At the time
these scrubbers were built, wet MEL scrubbers and wet caustic scrubbers
were the only scrubbers that could deliver high capture rates (over
90%) with reasonable reliability. Scrubber technology has improved and
other, less expensive, reagents are now preferred. Although Colstrip
Units 3 & 4 used MEL in the past, MEL is not readily available in the
region near the Colstrip plant. MEL is produced from a blending of
dolomitic lime with high calcium lime to achieve a lime with a
magnesium content of 3-6% or so. The lime is produced by calcination of
limestone. Dolomitic limestone is limestone with a significant amount
of dolomite, or calcium magnesium carbonate. Because there are no
dolomitic limestone deposits near the Colstrip plant, the dolomitic
lime must be sourced from remote locations. This increases the cost of
the lime (that is made from the dolomitic limestone). According to
Carmeuse, a supplier of MEL, the closest source of dolomitic lime is
1,000 miles away from the Colstrip plant and transportation would cost
$0.12 per mile per short ton plus a 24% fuel surcharge to
transport,\64\ or close to $150/short ton just for transportation of
the reagent. Because the lime would be blended in closer to the plant
with high calcium lime at perhaps an 8:1 ratio (reducing magnesium
content from about 40% to about 4-5% this would result in an increased
reagent cost of $15-$20 per ton. Assuming a high-calcium lime cost of
about $95/ton,\65\ this raises the cost of reagent by close to 20%
assuming constant reduction. Reagent use might be improved somewhat for
a given reduction level, but considering this is a unique scrubber
design, it is difficult to assess what the impact may be. Regardless,
reliance on a reagent source that is 1,000 miles away may cause
operating risks during the winter months if delivery was interrupted.
---------------------------------------------------------------------------

    \63\ See EIA Form 860 data.
    \64\ Email from Bob Roden, Carmeuse, to Jim Staudt, Andover
Technologies, July 31, 2012.
    \65\ Sargent & Lundy, ``IPM Model--Revisions to Cost and
Performance for APC Technologies, SDA FGD Cost Development
Methodology FINAL'', Prepared for US EPA, August 2010 see table 2.
---------------------------------------------------------------------------

    We also note that EarthJustice did not provide site-specific cost
information, for us to evaluate MEL. The cost of compliance is one of
the factors required to be considered by CAA section 169A(g)(1) and 40
CFR 51.308(d)(1)(i)(A). Based on all four factors, we continue to find
that the level of performance of the current SO2 removal
system for Colstrip Units 3 and 4 is satisfactory for this planning
cycle. We will re-evaluate additional SO2 controls for
Colstrip Units 3 and 4 in the next planning cycle.
    Comment: PPL stated that EPA properly concluded that RPGs do not
require additional emissions controls on Colstrip Units 3 and 4 and
that existing emissions controls at Units 3 and 4 already limit
emissions to levels below the presumptive BART limit. PPL stated that
EPA's RP conclusion should not be affected by EPA's ultimate
determination with respect to BART requirements for Colstrip Units 1
and 2 and that no further controls are warranted based on conclusions
regarding the extent of existing emissions controls and the cost-
ineffectiveness of further controls.
    Response: PPL did not provide specific information for us to
consider in making a change to our FIP. In any case, we have not
required additional controls for Colstrip Units 3 and 4 in our final
FIP.

K. Comments on Devon Energy

    Comment: MDEQ stated that we failed to provide information or
analysis of any visibility benefit that would result from the
application of NSCR for Devon Energy. MDEQ suggested that we must
consider visibility benefits as part of the Devon Energy reasonable
progress analysis, as the BART Guidelines include evaluation of
visibility impacts ``which would also appear to be required under the
reasonable progress guidelines.''
    Response: The four reasonable progress factors are the costs of
compliance, the time necessary for compliance, the energy and nonair
quality environmental impacts of compliance, and the remaining useful
life of any potentially affected sources CAA section 169A(g)(1) and 40
CFR 51.308(d)(1)(i)(A). Our Reasonable Progress Guidance states: ``In
determining reasonable progress, CAA section 169A(g)(1) requires States
to take into consideration a number of factors. However, you have
flexibility in how to take into consideration these statutory factors
and any other factors that you have determined to be relevant.'' \66\
As stated in our proposal at 77 FR 24069, for Devon, we considered Q/D
and potential reductions in Q/D, which are relevant to the goal of the
Regional Haze Rule, improving visibility.
---------------------------------------------------------------------------

    \66\ Reasonable Progress Guidance, p. 5-1.
---------------------------------------------------------------------------

    Comment: MDEQ commented that EPA should review the NOX
limit for Devon with respect to its averaging time and compliance
determining method for practical enforceability.
    Response: In the final FIP, we have made changes to the language in
40 CFR 52.1396 to clarify the requirements for Devon Energy.

L. Comments on Montana-Dakota Utilities

    Comment: Montana-Dakota Utilities (MDU) commented that the company
did not disagree with our Reasonable Progress determination. MDU stated
that, for EPA's reference, paragraph 3 on page 1 of the Sargent & Lundy
IPM model method document cautions as follows with respect to the
application of the model to smaller units:

    The costs for retrofitting a plant smaller than 100 MW increase
rapidly due to the economy of size. The older units which comprise a
large proportion of the plants in this range generally have more
compact sites with very short flue gas ducts running from the boiler
house to the chimney. Because of the limited space, the SCR reactor
and new duct work can be expensive to design and install.
Additionally, the plants might not have enough margins in the fans
to overcome the pressure drop due to the duct work configuration and
SCR reactor and therefore new fans may be required.

    MDU stated that Lewis & Clark Station is a small, 52 MW net
capacity unit. In addition, MDU believes that the fan margin is not
present at Lewis & Clark Unit 1 to overcome the pressure drop as
discussed in the Sargent & Lundy guidance.
    Response: MDU has not provided the information that would be
necessary for

us to determine whether or not to agree with the implied point of this
comment, which seems to be that EPA underestimated the cost of SCR.
First, MDU has not indicated whether there are, in fact, space
limitations at Lewis & Clark Station that would cause installation of
an SCR reactor and associated ductwork to be more expensive than the
cost estimate in our analysis. Second, MDU has not indicated whether
the additional pressure drop from installation of SCR at Lewis & Clark
Station would, in fact, require installation of new fans, and if so,
whether or not our cost analysis failed to factor in the cost of new
fans.
    Comment: MDU indicated that EPA uses a Retrofit Factor value of 1
for Lewis & Clark Station Unit 1 in the IPM Model calculation (factor B
in the EPA cost sheets) which indicates an average retrofit cost,
however, a higher value would be expected for Lewis & Clark since it is
a small facility (as discussed/cautioned above by Sargent & Lundy) and
could be difficult to retrofit. A more appropriate value between 1.3
and 2.0 is therefore recommended.
    Response: We disagree. MDU has not provided any data or information
to substantiate that a retrofit factor other than 1 is warranted for
Lewis & Clark Station. The IPM capital cost calculations for retrofits
already account for unit size. We note that capital cost does not vary
linearly with size in IPM. Instead, in the capital cost formula in IPM,
the cost varies exponentially with unit size (a least squares fit). The
IPM document states, ``The least squares curve fit was based upon an
average of the SCR retrofit projects.'' IPM Model--Revisions to Cost
and Performance for APC Technologies, SCR Cost Development Methodology,
Final, Sargent & Lundy, August 2010, Chapter 5, Appendix 5-2A, page 4-
5.
    We also disagree with the statement that a more appropriate
retrofit factor should be 1.3 to 2.0. The aforementioned IPM document
states that, ``Retrofit difficulties associated with an SCR may result
in capital cost increases of 30 to 50% over the base model.''
Therefore, the highest retrofit factor that might be considered would
be 1.5.
    This comment has not resulted in any change to our FIP proposal or
to our cost calculations for SCR.
    Comment: MDU stated that the model ``Type of Coal'' input indicates
``PRB'', but should be ``Lig,'' since Lewis & Clark burns lignite coal.
That stated, the ``Coal Factor'' value in the cell below ``Type of
Coal'' indicates lignite coal was actually considered. As such, this
recommendation is clerical in nature.
    Response: As shown in the ``Given/Assumptions'' spreadsheet in our
SCR cost analysis, we used a heating value of 6,714 Btu/lb, which we
considered to be representative of lignite coal. PRB coal would have a
much higher heating value.
    Comment: MDU stated that EPA used a NOX input emission
rate to the SCR of 0.26 lb/MMBtu, which is the low load emissions rate
of low NOX burners (LNB) and Separated Overfire Air (SOFA)
that MDU estimated in Table C.2-1 of Appendix C.2 of the Emissions
Control Analysis for Lewis & Clark Station Unit 1. The 0.25 lb/MMBtu
for LNB/SOFA at high load is a more appropriate rate to use as the
inlet to an SCR. While this does not result in a significant change to
the overall conclusions in the report, it is nonetheless important
because the EPA-derived cost was based on full load operation, as
opposed to lower load.
    Response: We disagree with the statement that we obtained the
emission rate of 0.26 lb/MMBtu from the low-load scenario presented in
Table C.2-1 of Appendix C.2 of MDU's Emissions Control Analysis.
Instead, as indicated in the ``Given/Assumptions'' spreadsheet of our
SCR cost analysis, we obtained the rate of 0.26 lb/MMBtu from Table
C.2-6 of MDU's analysis. Table C.2-6 is not identified by MDU as a low-
load scenario.
    Comment: MDU stated that, from the IPM model guidance, EPA did not
include factors N through V in the model calculations for operating
costs for Lewis & Clark Station's evaluations. Although factors N
through R and T through V are utility costs that were not needed in
EPA's evaluation, the catalyst cost (factor S) was applied based on an
alternative source. EPA references ``Cichanowicz (Jan 2010)'' with a
cost of $170/ft\3\ as compared to the IPM value of $8,000/m\3\
($226.53/ft\3\ in 2009$) and MDU's value of $214.29/ft\3\. MDU
recognized that a range of potential costs exist, and believes that
either the IPM value or the value MDU provided would be more
appropriate for EPA to use since they are based on industry and vendor
data respectively and are expected to represent a more site specific
value as opposed to a literature based value.
    Response: We disagree. The Cichanowicz document we used provided
actual catalyst costs observed over time. It demonstrates that catalyst
costs continue to decline. In fact, based on the trend displayed in the
graph on page 6-6 of the document, it is likely that catalyst costs in
upcoming years will be even lower than the $6,000/m\3\ assumed in our
FIP proposal. Current Capital Cost and Cost-Effectiveness of Power
Plant Emissions Control Technologies, J. Edward Cichanowicz, Prepared
for Utility Air Regulatory Group, January 2010, page 6-6, Figure 6-6.
This comment has not resulted in any change to our FIP proposal or to
our cost calculations for SCR.
    Comment: Similarly, to item e above, MDU noted that the cost EPA
associated with aqueous ammonia ($0.12/lb) is lower than the cost MDU
estimated of $0.70/lb. MDU recognized that a range of ammonia costs
exists, that the price of ammonia fluctuates over time, and that the
price is related to natural gas prices. As such, if SCR were to be
considered in the future, MDU would ask that site specific, local, as
delivered cost be evaluated at that time.
    Response: We disagree. In its own SCR cost spreadsheet, MDU did not
indicate the basis for its estimate of $0.70/lb. We used $0.12/lb based
on data provided to us by control technology vendors on cost of aqueous
ammonia. This comment has not resulted in any change to our FIP
proposal or to our cost calculations for SCR.
    Comment: MDU stated that, through the FR correction, EPA changed
the language on 77 FR 24071 to state that an 85% control efficiency was
used instead of the initially quoted 95% control efficiency for SDA and
baghouse. MDU believes this correction was in error. Table 172 in the
FR lists the control efficiency as 85% for SDA and baghouse and this
value should be corrected to 95% control efficiency for SDA and
baghouse as the textual representation in the FR was correct.
    Response: We disagree. We made the correction from 95% to 85%
because MDU's Emissions Control Analysis dated June 2011, at Table 1 on
page 14, shows an expected SO2 emission reduction of 850.3
tons per year, for SDA with baghouse. The baseline SO2
emissions listed in the table are 1,002.1 tons per year. This amount of
reduction represents 85% control efficiency. We presented these figures
at 77 FR 24071, Table 172. MDU later wrote to us on February 10, 2012,
to say that 70-90% control is the generally anticipated range of
SO2 control for this control option, and that 95% control
was also assumed and represented a screening level assumption for a
high degree of SO2 control. In its February 10, 2012
submittal, MDU did not indicate that Table 1 of their June 2011
submittal should be revised, so we used the figures presented in MDU's
Table 1.
    Comment: In Table 172 of the proposed FIP (77 FR 24071), EPA
provides a 10% control effectiveness for

both DSI with baghouse and existing scrubber mod; however, MDU stated
that this value should be changed to 70% to reflect the overall
reduction and not the incremental reduction as shown in Table 1 of
MDU's Emissions Control Analysis for Lewis & Clark Station Unit 1.
    Response: We disagree. We stated that we did use 70% overall
SO2 control effectiveness for DSI with baghouse, as well as
for existing scrubber mod, in our analysis. 77 FR 24071. However, we
also stated that existing SO2 controls at Lewis & Clark
Station, consisting of a flooded disc wet scrubber, have achieved up to
60% control under certain operating conditions. 77 FR 24070. We
obtained this information from MDU's analyses. 77 FR 24070, footnote
265. MDU's Emissions Control Analysis dated June 2011, at Table 1 on
page 14, lists an expected emissions reduction of 100.2 tons per year
for DSI with baghouse, and the same amount of reduction for existing
scrubber mod. This is a 10% reduction from the baseline emissions of
1,002.1 tons per year listed in that table. We relied on these figures
from MDU in listing a control effectiveness of 10% for DSI with
baghouse, as well as a control effectiveness of 10% for existing
scrubber mod. For all control options analyzed in our FIP proposal, we
present control effectiveness in terms of the reduction that might be
achieved from baseline emissions. In this case, the baseline emissions
already reflected a 60% level of SO2 control.
    Comment: EarthJustice argued that EPA should require Lewis and
Clark to switch from lignite fuel to natural gas as a reasonable
progress measure. The unit already uses natural gas for startup, there
is a natural gas supply close by, and thus switching to natural gas is,
in commenter's view, quite feasible and cost effective for Lewis and
Clark station. Switching to natural gas should be required in the FIP
to help achieve reasonable progress, as this measure would virtually
eliminate the unit's SO2 and PM emissions and would also
reduce NOX emissions. Although EPA dismissed fuel switching
as not cost effective, commenter argues that EPA vastly understated the
cost effectiveness of this measure.
    Commenter first stated that EPA has overstated the costs of
switching to natural gas, in large part because it has underestimated,
and in some cases ignored, the tremendous cost savings that would
result from not operating the facility's scrubber, multi-cyclone dust
collector, and coal preparation systems. EPA also relied on inflated
estimates for natural gas and natural gas supply pipelines provided by
MDU, which owns Lewis and Clark.
    Commenter also stated that EPA has improperly calculated the
emissions reductions achievable from fuel switching. EPA failed to take
into account the fact that the use of natural gas would replace the
existing SO2 and PM controls. Commenter stated that, in view
of the 54 kilometer distance from Lewis and Clark to the closest Class
I area, filterable PM must be considered. Thus, EPA should have
accounted for the pollution reductions that would be achieved with
natural gas from uncontrolled levels of SO2 and PM. Properly
calculated, fuel switching would eliminate 24,000 tons per year of
SO2, NOX and filterable PM. As EPA noted, Lewis
and Clark's remaining emissions would be ``negligible.''
    Commenter concluded that, even using EPA's inflated cost estimate,
when uncontrolled rates of SO2 and PM are used as the
baseline, the cost effectiveness of switching to natural gas at Lewis
and Clark station is $909/ton of SO2, NOX and PM
removed. This measure is highly cost effective and should be required
to help achieve reasonable progress.
    Response: We disagree. Although we do not believe it was
necessarily an error for us to rely on MDU's estimate of the price of
natural gas, we acknowledge that price estimates for natural gas can
vary, and that the $3.07/Mscf price of natural gas cited on page 129 of
the commenter's Technical Support Document, obtained from the Energy
Information Administration (EIA), is substantially lower than MDU's
estimate of $7.91/Mscf. However, even if we rely on the price cited by
the commenter, the cost of a fuel switch would still be excessive.
Using $3.07/Mscf, along with MDU's estimate of 3,282,876 Mscf of
natural gas which would be needed to fuel Lewis and Clark station year-
round solely on natural gas (not disputed by the commenter), we
calculate the annual cost of natural gas at $10,078,429. MDU estimated
the annual cost of coal at $5,754,732. The annual fuel cost
differential would therefore be $4,324,197. To this result we add the
annualized cost of constructing a natural gas pipeline ($1,699,200), as
we did in our FIP proposal.\67\ This yields a total annual cost of
$6,023,397. Dividing this result by an expected SO2 emission
reduction of 1,002 tons per year yields cost effectiveness of $6,011/
ton. Based on this cost and other factors for Lewis and Clark station
described in our FIP proposal at 77 FR 24072, we would still eliminate
fuel switching as a control option for SO2.
---------------------------------------------------------------------------

    \67\ Commenter's speculation that the existing pipeline could be
upgraded does not provide sufficient basis for us to supplant MDU's
estimated cost for a new pipeline with some other cost. We note
that, even if the upgrade were feasible and had zero cost, the cost
effectiveness of the SO2 reductions would still be well
over $4,000/ton.
---------------------------------------------------------------------------

    We disagree with the statement that a fuel switch would yield
``tremendous'' cost savings from not operating the facility's scrubber,
multi-cyclone dust collector, and coal preparation systems. Commenter
has not quantified the cost savings. We have no reason to believe they
would be ``tremendous.'' We believe the cost savings would be minimal
in comparison to other components of our cost calculations for a fuel
switch. The cost savings would likely consist primarily of avoidance of
electricity and maintenance costs for the equipment cited by the
commenter.
    Also, we disagree with the statement that we should have calculated
reductions from uncontrolled levels of SO2 and PM. In every
cost analysis of control options for our FIP, we calculate reductions
from an emissions baseline which is the current actual annual
emissions, consistent with the approach laid out in the 2005 Regional
Haze Rule, at 70 FR 39167, for calculating cost effectiveness of
control options. Commenter's citation to a 2008 letter sent by EPA in
the course of developing initial information for a FIP ignores the
basis for the action we actually proposed.
    We also disagree with the statement that a ``proper cost analysis''
would result in cost-effectiveness of $909/ton. Commenter apparently
calculated $909/ton based on reduction from uncontrolled emissions, for
the sum of three pollutants (PM, SO2 and NOX). We
have explained above why we do not use uncontrolled emissions as the
baseline. We also explained in our proposal that, in our reasonable
progress determinations, we were not evaluating controls for PM for
potentially affected sources, based on our analysis of the emissions
inventory and results from BART modeling. 77 FR 24055-56. Commenter has
not disputed those bases; commenter merely notes the 54 kilometer
distance to Theodore Roosevelt NP. Given these flaws, the commenter's
cost analysis provides no basis for us to reconsider our decision.
    Comment: Commenter noted that, although MDU proposed upgrades to
its existing SO2 and NOX pollution controls, EPA
failed even to require these measures to help achieve reasonable
progress. See 77 FR 24074. Commenter stated that MDU's proposal is
vastly inferior to fuel switching at reducing haze pollution, but MDU's

proposed controls are the bare minimum that EPA should have required
for reasonable progress.
    Commenter noted that MDU proposed to improve SO2 removal
to 70% by optimizing the existing particulate scrubber and lime
injection system with a proposed limit of 0.45 lb/MMBtu. EPA estimated
the cost effectiveness of this modification at $1,383/ton
SO2 removed. MDU also proposed SOFA and low NOX
burners (upgraded) to achieve a NOX emission rate of 0.25
lb/MMBtu. EPA estimated the cost effectiveness of this option as
$1,213/ton of NOX removed. Commenter stated that, although
the emissions reductions from these measures are modest, they are
highly cost effective and are the minimum that EPA should have required
from Lewis and Clark to achieve reasonable progress.
    Response: We disagree. MDU's proposal to improve SO2 and
NOX emission control was contained in its June 2011
Emissions Control Analysis, which was submitted in response to a CAA
section 114 information request from us. Under the Regional Haze Rule,
we are not bound by controls that a source has proposed when we make
our reasonable progress determination based on the four statutory
factors.
    With regard to the statement that cost-effectiveness of $1,383/ton
for SO2 and $1,213/ton for NOX is ``highly cost-
effective'' and should result in a requirement for emissions
reductions, commenter has not provided a basis for this conclusion. As
explained in our FIP proposal at 77 FR 24072 (for SO2) and
24074 (for NOX), in making our reasonable progress
determination for Lewis and Clark Station, we considered the following
four reasonable progress factors: cost of compliance, the time
necessary for compliance; the energy and nonair quality environmental
impacts of compliance; and the remaining useful life of the source. We
also took into account the following additional factors: size of the
facility, the baseline Q/D of the facility, and the potential reduction
in Q/D from the controls. Commenter has not disputed the
appropriateness of using the four reasonable progress factors and other
factors in our proposal.
    Comment: WEG commented that the determination in the proposed rule
that no additional SO2 controls are required on Lewis &
Clark Station is unreasonable. WEG notes that two highly effective
control options are available (fuel switch to natural gas at 99%
control effectiveness and SDA with baghouse at 85% control
effectiveness) and should be further considered.
    Response: We disagree. EPA did not evaluate control options for
Regional Haze FIP development solely based on emission control
effectiveness. As indicated in EPA's analysis, the cost of fuel
switching is estimated at $21,875 per ton of pollutant removed and the
cost of SDA with baghouse is estimated at $11,825 per ton of pollutant
removed. 77 FR 24072, Table 173. EPA has already explained that this
cost is excessive. WEG has not provided a reason to not consider the
cost excessive. Besides the cost of compliance, EPA also explained that
other factors were taken into consideration in determining whether
additional SO2 controls should be required at Lewis & Clark
Station, those being the time necessary for compliance, the energy and
nonair quality environmental impacts of compliance, the remaining
useful life of the facility, the size of the facility, the baseline Q/D
of the facility, and the potential reduction in Q/D from the controls.
WEG did not provide a reason to re-evaluate these other factors.
    Comment: WEG comments that EPA should re-examine its decision to
eliminate all control options for NOX and move to require
HDSCR + SOFA/LNB at Lewis & Clark Station. WEG notes that this control
option has a high control effectiveness of 87.5% and considers the cost
of $4,853 per ton of pollutant removed to be reasonable. To rule it out
alongside a fuel switch to natural gas, which has a much higher cost of
$41,934 per ton of pollutant removed, lacks reason. WEG stated that the
cost and visibility benefits of HDSCR + SOFA/LNB should be considered
individually, and the control option should be implemented because of
the great emissions reduction it achieves, and because the FIP is far
from attaining a Uniform Rate of Progress (URP) akin to the regulatory
rate. WEG also stated that the final analysis of control options took
into account only ``the most cost effective option (SOFA/LNB)'' when
weighing cost against overall reductions in emissions.
    Response: We disagree. EPA did consider control options
individually. At Step 5 of its NOX analysis, EPA mentioned
cost of HDSCR + SOFA/LNB in the same sentence as cost of a fuel switch
only because those two options happened to be the most expensive. 77 FR
24074. Besides the cost of compliance, EPA also explained that other
factors were taken into consideration in determining whether additional
NOX controls should be required at Lewis & Clark Station,
those being the time necessary for compliance, the energy and nonair
quality environmental impacts of compliance, the remaining useful life
of the facility, the size of the facility, the baseline Q/D of the
facility, and the potential reduction in Q/D from the controls. At Step
5, EPA explained how these factors were considered with respect to all
control options, not just SOFA/LNB. In the case of HDSCR + SOFA/LNB,
EPA explained that this control option was eliminated on the basis of
not only cost, but also on the basis of the small size of the facility
and the relatively small baseline Q/D of the facility. WEG has not
provided a reason to re-evaluate these other factors. With regard to
URP, that comment was addressed in a previous response.

M. Comments on Montana Sulphur and Chemical Company

    Comment: MSCC commented that the company agrees with the conclusion
in the proposed FIP that additional controls are not required at this
time. MSCC also stated it does not believe we should have considered it
to be a BART-eligible source. The company referenced several letters
and discussions with MDEQ that were previously submitted and had as
part of development of the regional haze plan for Montana.
    Response: Because the commenter ultimately agrees with the final
conclusion and controls are not required for MSCC, at this time, we
find the comment to be non-substantive.

N. Comments on Health, Ecosystem Benefits, Other Pollutants, and Coal
Ash

    Comment: Several commenters stated that haze pollution
significantly impacts human health and ecosystem health. Specifically,
commenters asserted that haze pollution, including haze pollutants
NOX, SO2 and PM, contributes to heart attacks,
asthma attacks, chronic bronchitis and respiratory illness, decreased
lung function, increased hospital admissions, and even premature death.
Another commenter stated that NOX and SO2 can
combine to create photochemical smog and ozone, which can exacerbate
health problems.
    Some commenters cited a 2010 Clean Air Task Force report in stating
that the Colstrip coal-fired power plant put 31 people at risk of
premature death, 48 people at risk of a heart attack, 47 people at risk
of acute bronchitis, and 534 at risk of an asthma attack each year.\68\
Several commenters encouraged EPA to finalize the regional haze
proposal citing their own health

problems, or the health problems of family members.
---------------------------------------------------------------------------

    \68\ Several commenters cited numbers that were similar to
these, but did not match them exactly.
---------------------------------------------------------------------------

    Some commenters stated that the negative health impacts of this
pollution disproportionately harm vulnerable populations, specifically
the young and elderly, and that this disproportionate harm potentially
makes this a case of environmental justice. A commenter claimed that
Colstrip causes a dark shadow on snow and takes human lives. One
commenter stated the rate of asthma in children in Rosebud County is
the third highest of all counties in the State, while another stated
the rate of birth abnormality in the area downwind of Colstrip is much
higher (34%) than in most other counties in Montana (10%). One
commenter stated that over 10% of Montana high school students were
estimated to have asthma in 2009. A commenter surmised that a 50%
reduction in pollution from Colstrip would help human health more than
eliminating pollutants from all other Montana sources.
    Some commenters expressed a willingness to pay more for power in
support of pollution control technology, with others stating that we
should all pay the full cost of energy and not pass it on as healthcare
costs. Another commenter stated that the cost of pollution controls,
especially at Colstrip, was small when compared to the health-related
benefits. Other commenters stated that the sources should not be
allowed to externalize the costs of their pollution onto the people,
who must pay for them in the form of health-related costs.
    Some commenters stated that haze pollution negatively impacts
ecosystem health. Commenters expressed concern for the effects of haze
pollution on plants and water bodies. Some commenters specifically
expressed concern over acid deposition from SO2 and
NOX emissions, which they argued can leach into drinking
water sources and harm crops. One commenter attributed high levels of
mercury in some Montana back country lakes to coal-fired power plant
emissions.
    Other commenters supported EPA's position that consideration of
health benefits is not relevant under the regional haze program.
    One commenter stated that we should regulate coal ash at Colstrip.
Another commenter expressed concern about acid rain, and one commenter
stated that various pollutants such as dioxin and formaldehyde were
byproducts of coal pollution.
    Response: We acknowledge the commenters' concerns regarding the
negative health impacts of haze-causing emissions. We agree that the
same PM2.5 emissions that cause visibility impairment can
cause respiratory problems, decreased lung function, aggravated asthma,
bronchitis, and premature death. We also agree that the same
NOX emissions that cause visibility impairment also
contribute to the formation of ground-level ozone, which has been
linked with respiratory problems, aggravated asthma, and even permanent
lung damage. We agree that these pollutants may have negative impacts
on vegetation, and reduce crop yields. However, for purposes of this
action, we are not authorized to consider these impacts in promulgating
our FIP, and we have not done so. However, to the extent that this FIP
will lead to reductions in these pollutants, there will be co-benefits
for public health.
    We recognize the importance of considering environmental justice;
for this action, we are finalizing emission limitations that will
result in emissions reductions that will benefit potential
environmental justice communities. Therefore, this action will have no
high adverse and disproportionate impact on potential environmental
justice communities.
    Mercury is not a visibility impairing pollutant, and was therefore
not included in our analysis. We also are not authorized to regulate
coal ash in this action.
    Comment: Some commenters noted that regional haze is not a health-
based standard, and that there are other recently enacted rules that
protect human health.
    Response: We agree that the Regional Haze Rule was not intended to
address health concerns. Regional Haze is not a health-based standard.

O. General Comments Supporting Our Proposal or for Stricter Controls

    Comment: NPCA and MATB commended EPA's required controls for the
Ash Grove and Holcim cement kilns. The Northern Cheyenne Tribe
expressed support of our proposal as a whole.
    Response: We acknowledge the support provided by these commenters.
    Comment: Overall, we received more than 47,000 comment letters from
members representing various organizations and concerned citizens
requesting that EPA mandate more stringent and effective controls, most
notably SCR, on eligible Montana sources. These comments were received
at the public hearings in Billings and Helena, Montana, by Internet,
and through the mail. Many of these commenters argued that SCR is
required at over 200 facilities in the U.S., and that SCR should
therefore also be required at the coal-fired plants in Montana. A mass
mailer from WEG claimed that SCR was shown to be cost-effective, but is
not required. Several comments more generally stated that EPA should
require the most modern, effective pollution controls on Montana
sources, but did not specifically discuss the desired requirements. The
Montana Conservation Voters pointed out that pollution from Colstrip
will be three times higher than if SCR were required.
    Response: Although we acknowledge the commenters' encouragement
that we adopt even stricter standards, the standards discussed in our
proposal are appropriate considering the costs and visibility
improvement.
    Comment: One commenter pointed out that Colstrip emits more
pollutants than the nine next largest haze producers, combined.
    Response: The commenter did not explain specifically what they were
requesting.
    Comment: A commenter pointed out that Colstrip 3 and 4 are as
highly polluting as Colstrip 1 and 2, and thought that Colstrip 3 and 4
should also be required to install additional controls.
    Response: As explained in our proposal, the modeled visibility
benefits are not sufficient for us to consider it reasonable to impose
additional controls for Colstrip units 3 and 4 for this planning
period. 77 FR 24066 and 77 FR 24067.
    Comment: One commenter stated that the upgrading of pollution
controls on coal-burning facilities also helps mitigate the effects of
climate change. A separate commenter requested that EPA's plan consider
CO2 because of its impacts on climate change, while another
stated that coal should no longer be burned, as such action would slow
global climate change.
    Response: While we understand the commenters' concerns with respect
to climate change, consideration of climate change is outside the scope
of this action. CO2 is a greenhouse gas (GHG) and is not
considered a visibility impairing pollutant. However, EPA implements
regulations that address GHGs in order to protect the public and the
environment from the negative impacts of climate change.

P. General Comments That the Proposal Is Too Stringent

    Comment: Various commenters generally stated they did not support
the proposed rulemaking. Their reasons included: It will negatively
affect the local economy; it will negatively affect the coal power
plant industry; electricity costs will increase; health

concerns are exaggerated; direct and indirect jobs/businesses would be
adversely affected; the costs outweigh the benefits; Colstrip is
already significantly regulated; there are no air quality issues in
Colstrip; and it will not result in noticeable visibility improvements.
One commenter insisted our proposal is part of a broader anti-coal plan
to shut down coal plants, while another stated that Congress should
legislate national energy policy rather than involving federal
agencies. One commenter stated that PPL is very committed to clean air
and environmental stewardship and another stated that Colstrip is
already heavily regulated and additional controls are unnecessary. One
commenter stated that mismanagement of forests causes more haze and
that Colstrip provides good jobs and has a good compliance record.
    Response: We acknowledge these general comments that opposed our
proposed action as being too stringent. We provide responses that
address some of these issues elsewhere in this action. This action is
based on the statutory and regulatory requirements for regional haze
which we have followed.

Q. General Comments on Visibility Improvement and Other Causes of Haze

    Comment: Some commenters stated that any controls required by our
action must demonstrate a perceptible visibility improvement and some
stated that the reductions in the proposal will not produce perceptible
visibility improvement. Other commenters said that there were no haze
issues in Montana and that the change in visibility is subjective. The
Montana Chamber of Commerce commented that our FIP is not based on
sound science, accurate measures, or proven measures that will solve
the problem.
    Some commenters stated that gravel roads and forest fire are the
real causes of haze.\69\ WETA commented that under the FIP, haze would
not be effectively reduced and EPA's regional haze plan should consider
all established sources of emissions and not just industrial
facilities. Another commenter suggested that money to clean up
pollution should be spent in urban areas where there are real problems,
not in rural areas like Montana. An individual submitted information
comparing Montana emissions from different sources.
---------------------------------------------------------------------------

    \69\ One commenter also mentioned idling trucks, oil refineries
and farms as causes of haze.
---------------------------------------------------------------------------

    One commenter noted that the proposed rule delays, by hundreds of
years, in some cases, achievement of the 2064 natural visibility goal.
Numerous commenters stated that EPA should not forego cost-effective
pollution controls when more progress is clearly needed to protect air
quality. Some commenters stated that there is currently haze at
Yellowstone that was not visible years ago.
    With regard to Colstrip, a commenter said that shutting down
Colstrip would not clear the haze and that areas outside Montana,
including Oregon, Washington, and China influence the haze at
Yellowstone. Another commenter stated that there is no haze in the town
of Colstrip and that the wind does not blow in the directions of
Yellowstone and Roosevelt.
    Response: We disagree that any controls required by our action must
demonstrate a perceptible visibility improvement. In a situation where
the installation of BART may not result in a perceptible improvement in
visibility, the visibility benefit may still be significant. The
Regional Haze Rule states ``even though the visibility improvement from
an individual source may not be perceptible, it should still be
considered in setting BART because the contribution to haze may be
significant relative to other source contributions in the Class I area.
Failing to consider less-than-perceptible contributions to visibility
impairment would ignore the CAA's intent to have BART requirements
apply to sources that contribute to, as well as cause, such
impairment.'' 70 FR 39129. Visibility impacts below the thresholds of
perceptibility cannot be ignored because regional haze is produced by a
multitude of sources and activities which are located across a broad
geographic area.
    We agree that industrial facilities are not the only causes of
haze. Our action considered the many contributors to haze including
industrial facilities. In this action, we also proposed changes to
Montana's Visibility SIP that would require BACT for open burning.
    Even though some Class I areas will not attain natural visibility
conditions by 2064, our action requires the controls that were
determined to be effective according to our evaluation. For those
sources subject to BART, we evaluated: (1) Cost of compliance, (2) the
energy and nonair quality environmental impacts of compliance, (3) any
existing pollution control technology in use at the source, (4)
remaining useful life of source, and (5) degree of improvement in
visibility which may reasonably be anticipated to result from the use
of such technology and we determined which controls should be required
according to that evaluation. In determining the measures necessary to
make reasonable progress and in selecting RPGs for mandatory Class I
areas within Montana, we took into account the following four factors:
(1) Costs of compliance, (2) time necessary for compliance, (3) Energy
and nonair quality environmental impacts of compliance; and (4)
remaining useful life of any potentially affected sources. CAA section
169A(g)(1) and 40 CFR 51.308(d)(1)(i)(A).
    For Colstrip, we evaluated visibility improvement at all Class I
areas within 300 km. As stated above we evaluated other sources of
haze, including but not limited to, gravel roads and forest fires. The
most impacted Class I areas were Theodore Roosevelt NP and UL Bend WA.
While sources outside Montana do contribute to haze in the Class I
areas within Montana, that does not preclude our obligation to evaluate
Colstrip Units 1 and 2 according to the five BART factors and to
evaluate Colstrip Units 3 and 4 according to the four reasonable
progress factors and to require additional controls where necessary.

R. Comments on Cost, Economic Impact, Jobs and Price to Consumers

    Comment: Some commenters stated that the proposed rule would have a
negative economic impact and a negative impact on job creation and
growth. Some commenters stated that PPL might shut down Colstrip Units
1 and 2 as a result of this action. One commenter explained that
shutting down power plants removes jobs, and prevents other businesses
from using the energy from the power plant, causing a domino effect. A
commenter submitted documents describing Colstrip's positive economic
and community impact. Another commenter said that specifically, Montana
has a large percentage of low income and senior citizens who would be
majorly burdened by an increase in utility cost and another commenter
said that the cost would also be very burdensome for the small business
community in the area. The Southeastern Montana Development Corporation
stated that the economic impact of this action would be devastating to
consumers. One commenter said that the costs were prohibitively
expensive and another said that the costs could put the plants at risk
for future investments due to lack of economic viability. A commenter
suggested that the initial cost of investment at Colstrip 1 and 2,
including the cost of debt and capital, would be in excess of $82
million and that the capital cost, plus operating cost of $377 million
could result in a 19.6% increase in the cost of production. Another
commenter suggested that the cost of electricity could increase by a

factor of 20 in 3-4 years. One commenter urged us to consider the
indirect ways that controls on Colstrip 3 & 4 could affect electric
rates. Numerous commenters stated that the reason EPA was not requiring
SCR was to save polluters money.
    Other commenters said that the health costs of pollution and
economic benefit from tourism should be considered. One commenter said
that the health related costs from Colstrip are estimated to be $230
million annually. Another commenter stated that air pollution controls
are cost effective based on an EPA report. One commenter said that
pollution hinders the Billings economy because the city's economic
vitality is linked to high quality life-styles, while another noted
that haze diminishes tourists' scenic vistas.
    Some commenters pointed out that the proposed rule would create
jobs. One commenter stated that complying with the rule would create
good, high-paying jobs for Montana's skilled work force, including
boilermakers, laborers and pipefitters. Numerous commenters stated that
nearly 1,000 full-time jobs could be created at Colstrip from
installing pollution control equipment. One commenter said that the
Colstrip plant will not shut down just because added technology is
required.
    Many commenters expressed a willingness to pay more for power in
support of pollution control technology. Others similarly stated that
we should all pay the full cost of energy and not pass it on to
healthcare. Some commenters stated that they thought PPL could afford
to pay for additional controls based on the company's profit. A report
submitted by Power Consulting, Inc. found that the typical residential
customer's bill would increase by 55 to 89 cents if SCR were required
on Colstrip unit 4. The overall conclusion from that report was that
the impact of a required SCR retrofit on customer's rates would be
small enough that it would not disrupt household budgets nor cause a
significant impact on the Montana economy.
    Response: EPA's evaluation of capital and annual expenses
associated with implementation of the FIP shows such expenses to be
justified by the degree of improvement in visibility in relationship to
the cost of implementation. BART requires that we evaluate: (1) Cost of
compliance, (2) the energy and nonair quality environmental impacts of
compliance, (3) any existing pollution control technology in use at the
source, (4) remaining useful life of source, and (5) degree of
improvement in visibility which may reasonably be anticipated to result
from the use of such technology. In determining the measures necessary
to make reasonable progress and in selecting reasonable progress goals
for mandatory Class I areas within Montana, we must take into account
the following four factors: (1) Costs of compliance, (2) time necessary
for compliance, (3) Energy and nonair quality environmental impacts of
compliance; and (4) remaining useful life of any potentially affected
sources. CAA section 169A(g)(1) and 40 CFR 51.308(d)(1)(i)(A). The cost
of electricity to consumers and the overall impact on the economy is
outside the scope of our evaluation for this action.
    Although we did not consider the potential positive benefits to
local economies in making our decision, we do expect that improved
visibility would have a positive impact on tourism-dependent local
economies. Also, the retrofits required are large construction projects
that will take up to five years to complete. These projects will
require well-paid, skilled labor which can potentially be drawn from
the local area and support local growth.
    Comment: A commenter stated that EPA should have included, as
associated per-unit costs, consideration of the ``wider market
consequences'' of a potential shutdown of generating capacity at
Colstrip 1 and 2. The commenter says that, ``[i]f the cost of
production resulting from this rule * * * exceeds the market value of
power, PPL may make a decision to shutter the plant.'' The commenter
also states that, ``[b]ased on an analysis of production cost data,
there is at least some chance that Colstrip Units 1 and 2 would become
uneconomical as a result of mandated upgrades.'' Specifically,
commenter estimated that the ``all-in'' cost of production of
electricity post-controls is $25.591 per megawatt-hour, a 19.6%
increase over the current $21.40 per megawatt-hour cost of production
reported in Federal Regulatory Commission filings. Commenter stated
that, compared to current market prices from a regional trade
publication,\70\ Colstrip 1 and 2 would often be uneconomical at that
estimated cost.
---------------------------------------------------------------------------

    \70\ Commenter cited the trade publication ``Clearing Up,''
which commenter stated reports on prices at the Mid-Columbia trading
club.
---------------------------------------------------------------------------

    The commenter also argued that a closure at Colstrip 1 and 2 would
decrease available electrical generation in the northwestern U.S. The
commenter stated that we wrongly failed to consider these factors of
potential plant closure and the subsequent constriction of power supply
in our analyses.
    Response: Analyzing the wider market consequences of a potential
shutdown of generating capacity at Colstrip 1 and 2 involves many
complicated factors and it is unclear from the information provided by
the commenter that Colstrip Units 1 and 2 would, in fact, shut down. As
noted previously, we have received conflicting information regarding
potential rate increases. Specifically, a report submitted by Power
Consulting, Inc. found that the typical residential customer's bill
would increase by 55 to 89 cents if SCR were required on Colstrip unit
4. The BART Guidelines allow for the consideration of unusual
circumstances that justify taking into consideration the conditions of
the plant and the economic effects of requiring the use of a given
control technology. The BART Guidelines state:

    [t]hese effects would include effects on product prices, the
market share, and profitability of the source. Where there are such
unusual circumstances that are judged to affect plant operations,
you may take into consideration the conditions of the plant and the
economic effects of requiring the use of a control technology. Where
these effects are judged to have a severe impact on plant operations
you may consider them in the selection process, but you may wish to
provide an economic analysis that demonstrates, in sufficient detail
for public review, the specific economic effects, parameters, and
reasoning.

70 FR 39171. The commenter has not provided any basis that unusual
circumstances exist here. Nor has the commenter providing any
information that indicates a shutdown will occur that we could have
taken into account in our analysis. The owners of Colstrip Units 1 and
2 have made no indication that there are unusual circumstances present
that warrant taking wider market consequences into consideration.

S. Comments About Other Forms of Energy

    Comment: We received comments regarding alternative forms of
energy. Some commenters believed that wind energy would create more
jobs while others believed that it would not create as many jobs
compared to coal fired power plants. Some commenters stated that wind
energy was cheaper to produce while one commenter pointed out that the
government subsidizes wind energy. One commenter believed that the wind
farm in Judith Gap produces energy more cheaply compared to the
Colstrip coal plant. One commenter stated that our energy

should be focused on renewable sources rather than coal and another
commenter stated that the most important thing we can do to slow global
warming is to stop burning coal.
    Response: While we do generally acknowledge that many kinds of
renewable energy do not produce haze-causing pollutants, and
transitioning to those sources of energy could lead to visibility
improvements. In this action we are required to review specific
retrofit options for specific sources subject to BART or the sources
analyzed under reasonable progress. Renewable energy technology is not
a retrofit option for these sources and is outside the scope of our
determinations and regulatory requirements in this action.

T. Other Miscellaneous Comments

    Comment: One commenter asked whether EPA was concerned that
requiring these facilities to install emissions control equipment to
address fine particles and precursors might impact the effectiveness of
equipment installed to address other pollutants.
    Response: The control technologies that are required will not
negatively impact the effectiveness of equipment installed to address
other pollutants.
    Comment: One commenter asked whether the agency was concerned that
the technologies prescribed to address particles and precursors might
also impact the efficiency and reliability of kilns, boilers,
generators and other essential equipment.
    Response: The control technologies required will not negatively
impact the efficiency and reliability of kilns, boilers, generators and
other essential equipment. As required under BART, we evaluated the
energy impacts for each control option considered. 70 FR 39168 and 70
FR 39169. These impacts are discussed in the relevant sections of the
proposed rule and in all cases are minor. In addition, as required
under BART, we evaluated the technical feasibility for each control
option considered. Where we have selected additional controls, the
controls are shown to be technically feasible at similar facilities.
Issues associated with the reliability of the emission units, if any,
are resolvable.
    Comment: MDEQ requested that EPA extend the comment period to sixty
days from the date of the publication of corrections, or July 16, 2012.
    Response: The comment period for our proposal closed on June 19,
2012. We carefully considered the request for an extension to the
comment period. We took into consideration how an extension might
affect our ability to consider comments received on the proposed action
and still comply with our consent decree deadlines. We do note that our
May 1, 2012, public hearing in Helena, Montana and May 2, 2012, public
hearing in Billings, Montana were well attended and provided an
opportunity for people to comment on our proposal. We also note that
the corrections published May 17, 2012, (77 FR 29270) primarily amended
typographical errors.\71\
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    \71\ We corrected some technical information in the Holcim
SO2 BART analysis. See 77 FR 29270.
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    Comment: MDEQ suggested that EPA issue a request for additional
comment to clarify the scope of the proposed FIP. MDEQ asserted that
such a clarification is necessary to prevent confusion among the public
regarding the Regional Haze Rule's prevention and correction of adverse
health effects, about which EPA received multiple comments. MDEQ warned
that ``the level of this misperception threatens to pervert not only
the National Goal, but, ostensibly, the public health goals of Section
110.''
    Response: We do not agree that the scope of the proposed FIP
requires clarification. At no point in the proposed FIP did we discuss
public health impacts as a consideration in our analyses, as they were
not. As stated elsewhere, we agree that the Regional Haze Rule is not a
health-based standard, and that we are not authorized to consider
public health impacts in promulgating our FIP for purposes of this
action. However, we have not been presented any information from the
public to indicate that there is confusion that that reduction of
visibility impairing pollutants also provides health benefits.
    Comment: One commenter stated that the Cheyenne Reservation was
given Class I air quality designation and that according to that
designation there is not supposed to be any degradation of that air.
    Response: The Regional Haze Rule requires analysis for the 156
mandatory Class I areas listed at 40 CFR Part 81. The Cheyenne
Reservation is not one of these federally mandated Class I areas.
    Comment: WEG stated that EPA overlooked, in two respects, the
requirement of section 110(l) of the Act to prevent interference with
attainment or maintenance of the NAAQS. First, WEG stated that EPA has
not demonstrated that this FIP adequately safeguards the 2006
PM2.5 NAAQS, the 2008 ozone NAAQS, the 2010 1-hour
NO2 NAAQS, and the 2010 1-hour SO2 NAAQS. In
particular, WEG noted that the FIP emissions limitations are generally
expressed as 30-day rolling averages, which, in WEG's view, do not
adequately protect short-term NAAQS such as the 2010 1-hour
SO2 and NO2. Second, WEG argued that several BART
emissions limitations are relaxations that may impact the NAAQS. As an
example, WEG cited another portion of its comments in which WEG argued
that the BART emissions limitations for Corette will allow actual
emissions from Corette to increase. WEG concluded that EPA must conduct
a 110(l) demonstration in order to protect public health and not
interfere with maintenance and attainment of the NAAQS.
    Response: EPA disagrees with WEG. In relevant part, section 110(l)
provides that EPA shall not approve a revision of a plan if the
revision would interfere with any applicable requirement concerning
attainment and reasonable further progress or any other applicable
requirement of the CAA. First, WEG does not explain how section 110(l)
applies to EPA's initial promulgation of a FIP for certain regional
haze requirements when there is no existing SIP to meet those
requirements. Second, to the extent that section 110(l) applies, EPA's
promulgation of this FIP satisfies its requirements. It is EPA's
consistent interpretation of section 110(l) that a SIP revision does
not interfere with attainment and maintenance of the NAAQS if the
revision at least preserves the status quo air quality by not relaxing
or removing any existing emissions limitation or other SIP requirement.
EPA does not believe that a full attainment or maintenance
demonstration for each NAAQS is required for every SIP revision under
section 110(l).
    In this case, the FIP imposes new emissions limitations on a number
of existing sources, and it does not relax any existing emissions
limitations or other SIP requirements. WEG's statement that actual
emissions at Corette and other BART sources might rise to the BART
limit misses the point: In the absence of the BART limit (or any other
limit), those actual emissions could increase much more. In other
words, imposing an emissions limitation where one did not exist before
is necessarily a more stringent requirement, regardless of actual
emissions. Nor does WEG explicitly identify any existing emissions
limitation or other SIP requirement that is relaxed by the FIP. For
that matter, nothing in the proposal, or in the preamble or regulatory
text for this rule, purports to modify any existing SIP-approved
emissions limitation or other SIP requirement. Thus, even if there were
such a requirement--and WEG has identified none--it would not be

relaxed by this FIP. EPA therefore concludes that, to the extent that
section 110(l) is applicable to this FIP, its requirements are
satisfied.
    Comment: Commenter stated that the input of Montana residents
should be given more weight than the input of special interest groups
that receive support from outside the State. Commenter also requested
that future hearings be held in areas of impact.
    Response: Any commenter who submits a comment on the proposed FIP,
either orally or written, during the public comment period is entitled
to do so. EPA takes all comments into consideration in making its final
decision on the FIP. If future hearings are required for any reason, we
will do the best we can to ensure access is available to all those who
wish to participate.

V. Changes From Proposed Rule and Reasons for the Changes

A. Emission Limits for Corette

    We proposed a PM emission limit of 0.10 lb/MMBtu for Corette at 40
CFR 52.1396(c). We inadvertently stated that we were imposing an
emission limit of 0.10 lb/MMBtu in the preamble to our proposed FIP (77
FR 24047) and also at 40 CFR 53.1396(c)(1). PPL commented that the
emission limit in the proposed FIP was flawed and PPL provided
additional information indicating that over the past five years, stack
test results have shown that PM emissions have ranged from 0.059 lb/
MMBtu to 0.252 lb/MMBtu. We have changed the emission limit in the
final regulatory requirements at 40 CFR 1396(c)(1). In the final FIP,
we are establishing a PM emission limit of 0.26 lb/MMBtu.
    We proposed a SO2 emission limit of 0.70 lb/MMBtu and a
NOX emission limit of 0.40 lb/MMBtu for Corette at 40 CFR
52.1396(c). In the final FIP, we are establishing a SO2
emission limit of 0.57 lb/MMBtu and a NOX emission limit of
0.35 lb/MMBtu. We have made this change as a result of the comments we
received. One commenter stated that EPA must increase the limits to no
less than 0.81 lb/MMBtu for SO2 and 0.46 lb/MMBtu for
NOX in order to account for compliance over a 30-day rolling
average. By contrast, another commenter stated that our proposed
emission limits were too high and would actually result in increased
emissions.
    Based on these comments, we have reassessed the SO2 and
NOX emission limits for Corette. In order to establish
appropriate emission limits, we conducted a statistical analysis of the
monthly emissions data contained in the CAMD emissions system. For the
period 2000-2010, the 99th percentile monthly SO2 emission
rate was 0.548 lb/MMbtu. Similarly, the 99th percentile monthly
NOX emission rate was 0.335 lb/MMBtu. In our final action,
we are establishing emission limits slightly above these 99th
percentile emission rates in order to allow a sufficient margin for
compliance. This is because the emission limits must apply at all
times, including during startup, shutdown, and malfunction. The revised
emission rates are 0.57 lb/MMBtu for SO2 and 0.35 lb/MMBtu
for NOX, both on a 30-day rolling average. We have revised
the emission limits for Corette contained in section 52.1396(c)(1)
accordingly.

B. Changes to 40 CFR 52.1396(c)(2)--Emission Limitations for Cement
Kilns

    In response to a comment from Holcim that EPA failed to consider
the NOX control technology already installed at the Trident
cement plant, and that EPA failed to give proper weight to the
excessively high average cost-effectiveness ($4,279/ton) and
incremental cost-effectiveness ($8,029/ton) of a switch to indirect
firing and a Low-NOX Burner (LNB), we have removed switching
to indirect firing and a LNB from consideration as an option for
further reducing NOX emissions and are treating any
NOX emission reduction that may have been achieved from
installation of a new burner as part of the emissions baseline. We have
recalculated the BART limit for NOX to reflect a 50%
reduction in NOX emissions from that baseline by addition of
SNCR alone, rather than the 58% reduction we previously used, which
reflected a switch to indirect firing and LNB plus SNCR. The
recalculated NOX BART limit is 6.5 lb/ton clinker. We have
replaced the NOX emission limit of 5.5 lb/ton clinker from
our proposal with 6.5 lb/ton clinker, on a 30-day rolling average.
    Also, during our evaluation of comments on PM BART from Ash Grove,
we found that the table of emission limits for cement kilns, at section
52.1396(c)(2) of our proposal, needed to clarify that the PM emission
limit for Ash Grove is in lb/hr, not lb/ton clinker. Only the PM
emission limit for Holcim is in lb/ton clinker. The column header for
PM emission limits for both cement kilns erroneously said ``lb/ton
clinker.'' We have corrected this error by changing the header from
``PM Emission Limit (lb/ton clinker)'' to ``PM Emission Limit.'' We did
not change the text of the PM emission limit for Ash Grove, as it is
already clear in that text that the limit is in lb/hr. However, at the
bottom of the column, we have clarified the PM emission limit for
Holcim to say ``0.77 lb/ton clinker'' rather than``0.77 lb/ton.''

C. Change to 40 CFR 52.1396(d)--Compliance Date

    In response to a comment from Ash Grove which identified the
failure of our regulatory text at 40 CFR 52.1396(d) to specify the
SO2 and PM compliance dates described in the preamble to our
proposed rule, we have revised 40 CFR 52.1396(d) to read as follows:

    The owners and operators of the BART sources subject to this
section shall comply with the emissions limitations and other
requirements of this section as follows, unless otherwise indicated
in specific paragraphs: Compliance with PM limits is required within
30 days of the effective date of this rule. Compliance with
SO2 and NOX limits is required within 180 days
of the effective date of this rule, unless installation of
additional emission controls is necessary to comply with emission
limitations under this rule, in which case compliance is required
within five years of the effective date of this rule.

D. Change to 40 CFR 52.1396(e)(3)--CEMS for Cement Kilns

    In response to a comment from Ash Grove Cement that this section
should be revised to include an exception from CEMS data collection
during CEMS breakdowns, repairs, calibration checks and zero and span
adjustments, we have added the following language from 40 CFR part 60,
subpart F, New Source Performance Standards for cement kilns, at 40 CFR
60.63(b):

    You must operate the monitoring system and collect data at all
required intervals at all times the affected source is operating,
except for periods of monitoring systems malfunctions, repairs
associated with monitoring system malfunctions, and required
monitoring system quality assurance or quality control activities
(including, as applicable, calibration checks and required zero and
span adjustments).

    Also, during our evaluation of comments from Ash Grove on CEMS
requirements, we found that section 52.1396(e)(3) inadvertently failed
to cross-reference the requirements for CEMS for cement kilns at 40 CFR
60.63(g). Section 52.1396(e)(3) only cross-referenced 60.63(f). There
are important requirements for cement kiln CEMSs at 40 CFR 60.63(g), as
well as important CEMS requirements at 60.63(h) which are cross-
referenced only by 60.63(g) and not by 60.63(f). We have therefore
added ``and (g),'' such that the first sentence of section
52.1396(e)(3) now reads as follows:

    At all times after the compliance date specified in paragraph
(d) of this section, the owner/operator of each unit shall maintain,

calibrate, and operate a CEMS, in full compliance with the
requirements found at 40 CFR 60.63(f) and (g), to accurately measure
concentration by volume of SO2 and NOX
emissions into the atmosphere from each unit.

E. Change to 40 CFR 52.1396(e)(4)(ii)--Compliance Determination Methods
for SO2 and NOX at Cement Kilns

    In response to a comment from Ash Grove that the formula at section
52.1396(e)(4)(ii) of our proposal incorrectly expresses the
concentrations of SO2 and NOX in grains per dry
standard cubic foot, rather than in parts per million, we have deleted
the equation E = (CsQs)/(PK) from this section, as well as the
definitions of terms in that equation, and replaced it with the
following equation, which appears in the proposed amendments to 40 CFR
part 60, subpart F, New Source Performance Standards for cement kilns,
published in the Federal Register on July 18, 2012:
[GRAPHIC] [TIFF OMITTED] TR18SE12.068

Where:

ED = 30 kiln operating day average emission rate of
NOX or SO2, lb/ton of clinker;
Ci = Concentration of NOX or SO2
for hour i, ppm;
Qi = volumetric flow rate of effluent gas for hour i,
where
Ci and Qi are on the same basis (either wet or
dry), scf/hr;
Pi = total kiln clinker produced during production hour
i, ton/hr;
k = conversion factor, 1.194 x 10-7 for NOX
and 1.660 x 10-7 for SO2
n = number of kiln operating hours over 30 kiln operating days, n =
1 to 720.
For each kiln operating hour for which you do not have at least one
valid 15-minute CEMS data value, use the average emissions rate (lb/
hr) from the most recent previous hour for which valid data are
available.

F. Change to 40 CFR 52.1396(f)(1) and (f)(2)--Compliance Determinations
for PM BART Limits at EGUs and Cement Kilns

    In response to a verbal comment from Holcim, in a meeting with EPA
in June of 2012 on the proposed FIP, that BART sources should be
allowed to retain the PM stack testing schedule already established
under State permits, we have added the following sentence, after the
sentence in sections 52.1396(f)(1) and (f)(2) that requires the first
annual PM performance stack test for PM within 60 days after the PM
compliance deadline:

    The results from a stack test meeting the requirements of this
paragraph that was completed within 12 months prior to the
compliance deadline can be used in lieu of the first stack test
required. If this option is chosen, then the next annual stack test
shall be due no more than 12 months after the stack test that was
used.

    The meeting between Holcim and EPA is documented in the docket for
this rulemaking.

G. Change to 40 CFR 52.1396(f)(2)--Compliance Determinations for Cement
Kiln PM BART Limits

    Consistent with our clarification of the table of PM emission
limits for cement kilns at 40 CFR 52.1396(c)(2), we have clarified 40
CFR 52.1396(f)(2), to indicate that the emission rate of PM shall be
reported in lb/hr for Ash Grove and in lb/ton clinker for Holcim. We
have also clarified that the average of the results of three test runs
for PM shall be used for demonstrating compliance. Specifically, we
have added the following language after the third sentence of section
52.1396(f)(2):

    The average of the results of three test runs shall be used for
demonstrating compliance. For Ash Grove, the emission rate of
particulate matter shall be computed for each run in pounds per hour
(lb/hr). For Holcim, the emission rate (E) of particulate matter
shall be computed for each run in lb/ton clinker, using the
following equation: * * *
    We have also revised section 52.1396(f)(2) in response to a comment
from Ash Grove that the equation at 40 CFR 52.1396(e)(4)(ii), cross-
referenced by this section 52.1396(f)(2), for calculating emissions in
lb/ton clinker, is not valid for calculating SO2 and
NOX emissions, but is only valid for calculating PM
emissions. Therefore, we have moved this equation from section
52.1396(e)(4)(ii) to section 52.1396(f)(2). We have also changed the
pollutant in the equation to PM. We have also clarified (as explained
above) that the equation is to be used for calculating PM in lb/ton
clinker only for Holcim, not for Ash Grove (which, as explained above,
is subject to a PM emission limit in lb/hr, not in lb/ton clinker).
Below is the equation we have now inserted into section 52.1396(f)(2),
immediately after the revised text described above:

E = (CsQs)/(PK)

Where:

E = emission rate of PM, lb/ton of clinker produced
Cs = concentration of PM in grains per standard cubic foot (gr/scf)
Qs = volumetric flow rate of effluent gas, where Cs and Qs are on
the same basis (either wet or dry), scf/hr
P = total kiln clinker production rate, tons/hr, and
K = conversion factor, 7000 gr/lb

    We have also deleted the cross-reference to section
52.1396(e)(4)(ii) for this equation.

H. Change to 40 CFR 52.1396(h)(6)--Recordkeeping Requirements for
Cement Kilns

    In response to a comment from Ash Grove that the reference to ``40
CFR Part 75'' should be deleted because Part 75 applies only to
electrical generating units, not to cement kilns, we have deleted that
reference. We note that since the monitoring requirements for cement
kilns in the FIP, at 40 CFR 52.1396(e)(3) and (4), and at 40 CFR
52.1396(f)(2), do not cross-reference Part 75, there are no applicable
Part 75 recordkeeping requirements in the FIP. Section 52.1396(h)(6)
now reads as follows:

    Any other records required by 40 CFR part 60, subpart F, or 40
CFR part 60, Appendix F, Procedure 1.

I. Changes to 40 CFR 52.1396(i)--Reporting

    In response to a comment from Ash Grove that the first sentence of
this section mistakenly references 40 CFR 53.1395(n) and (o), rather
than 52.1396(n) and (o), we have made the correction.

J. Change to 40 CFR 52.1396(i)(1) and (i)(2)--Reporting for CEMS for
SO2 and NOX

    In response to a comment from Ash Grove that the reporting
frequency for CEMS excess emission reports and CEMS performance reports
for cement kilns should be changed from quarterly to semiannual,
because reporting requirements under other programs (Title V and
NESHAP) only require semiannual reporting, we have changed the
frequency to semiannual, but have kept the frequency at quarterly for
EGUs.
    We note that the general provisions of NSPS subpart A, at 40 CFR
60.7(c), which we used as a template for our FIP provisions for CEMS
reporting, require semiannual excess emission reports and monitoring
system performance reports, except when more frequent reporting is
specifically required by an applicable subpart, or if the
Administrator, on a case-by-case basis, determines that more frequent
report is necessary to accurately assess the compliance status of the
source. NSPS subpart F for cement kilns does not specify more frequent
reporting.
    Therefore, we have deleted ``quarterly'' from the first sentence of
section 52.1396(i)(1) and from the first sentence of section
52.1396(i)(2). After the first sentence in each of those

sections, we have inserted the following sentence: ``Reports shall be
submitted quarterly for EGUs and semiannually for cement kilns.''

K. Changes to 40 CFR 52.1396 for Devon Energy, Blaine County 1
Compressor Station

    In the final FIP, we are clarifying testing requirements,
monitoring, recordkeeping and reporting requirements, and emission
limitations for Devon Energy, Blaine County 1 Compressor
Station. We made these changes in response to a comment stating that
the requirements for this source were not practically enforceable.
    We have changed the text at 40 CFR 52.1396(c)(3) to read, ``The
owners/operators of LP, Blaine County 1 Compressor Station
shall not emit or cause to be emitted from each 5,500 horsepower
Ingersoll Rand 616 natural gas-fired compressor engine installed at the
facility, total NOX in excess of 21.8 lbs/hr (average of
three stack test runs).'' We have made this change to clarify that the
emission limit of 21.8 lbs/hr applies to each of the 5,500 horsepower
Ingersoll Rand 616 natural gas-fired compressor engines installed at
the facility and that the emission rate will be determined by averaging
the results of three stack test runs.
    We have changed the text at 40 CFR 52.1396(e)(5) to read, ``The
owner/operator of Blaine County 1 Compressor Station shall
install a temperature-sensing device (i.e. thermocouple or resistance
temperature detectors) before the catalyst in order to monitor the
inlet temperatures of the catalyst for each engine. The owner/operator
shall maintain the exhaust temperature at the inlet to the catalyst for
each engine at a minimum of least 750 [deg]F and no more than 1250
[deg]F in accordance with the catalyst manufacturer's specifications.
Also, the owner/operator shall install gauges before and after the
catalyst for each engine in order to monitor pressure drop across the
catalyst, and that the owner/operator maintain the pressure drop within
 2'' water at 100% load plus or minus 10% from the pressure
drop across the catalyst measured during the initial performance test.
The owner/operator shall follow the manufacturer's recommended
maintenance schedule and procedures for each engine and its respective
catalyst. The owner/operator shall only fire each engine with natural
gas that is of pipeline-quality in all respects except that the
CO2 concentration in the gas shall not be required to be
within pipeline-quality.'' We have made this change to clarify that it
is the exhaust temperature that must be maintained at a minimum of at