Air Plan Approval; Ohio; Attainment Plan for the Lake County SO2, 3986-3991 [2019-02210]
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Federal Register / Vol. 84, No. 31 / Thursday, February 14, 2019 / Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R05–OAR–2015–0699; FRL–9989–48–
Region 5]
Air Plan Approval; Ohio; Attainment
Plan for the Lake County SO2
Nonattainment Area
Environmental Protection
Agency (EPA).
ACTION: Final rule.
AGENCY:
The Environmental Protection
Agency (EPA) is approving, under the
Clean Air Act (CAA), Ohio’s plan for
attaining the 1-hour sulfur dioxide (SO2)
primary national ambient air quality
standard (NAAQS) in the Lake County
SO2 nonattainment area. EPA proposed
to approve Ohio’s Lake County plan as
a revision to Ohio’s SO2 State
Implementation Plan (SIP) on August
21, 2018. EPA received public
comments on the proposed rulemaking
and is providing responses to the
comments below.
DATES: This final rule is effective on
March 18, 2019.
ADDRESSES: EPA has established a
docket for this action under Docket ID
No. EPA–R05–OAR–2015–0699. All
documents in the docket are listed on
the www.regulations.gov website.
Although listed in the index, some
information is not publicly available,
i.e., Confidential Business Information
(CBI) or other information whose
disclosure is restricted by statute.
Certain other material, such as
copyrighted material, is not placed on
the internet and will be publicly
available only in hard copy form.
Publicly available docket materials are
available either through
www.regulations.gov or at the
Environmental Protection Agency,
Region 5, Air and Radiation Division, 77
West Jackson Boulevard, Chicago,
Illinois 60604. This facility is open from
8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding Federal holidays. We
recommend that you telephone Mary
Portanova, Environmental Engineer, at
(312) 353–5954 before visiting the
Region 5 office.
FOR FURTHER INFORMATION CONTACT:
Mary Portanova, Environmental
Engineer, Control Strategies Section, Air
Programs Branch (AR–18J),
Environmental Protection Agency,
Region 5, 77 West Jackson Boulevard,
Chicago, Illinois 60604, (312) 353–5954,
portanova.mary@epa.gov.
SUPPLEMENTARY INFORMATION:
Throughout this document whenever
SUMMARY:
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‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean
EPA. Ohio’s nonattainment SIP
submittal of April 3, 2015,
supplemented on October 13, 2015 and
on March 13, 2017, addressed Ohio’s
Lake County, Muskingum River, and
Steubenville OH–WV SO2
nonattainment areas. This final action
addresses only the Lake County portion
of Ohio’s nonattainment SIP submittal.
The Muskingum River and Steubenville
portions of Ohio’s submittal will be
addressed in future action.
This SUPPLEMENTARY INFORMATION
section is arranged as follows:
I. Background
II. Public Comments and EPA Responses
III. What action is EPA taking?
IV. Statutory and Executive Order Reviews
I. Background
Lake County, Ohio, was designated
nonattainment for the 2010 1-hour
primary SO2 NAAQS on August 5, 2013
(78 FR 47191). As required by the CAA,
Ohio developed a plan to provide for
attainment of the SO2 NAAQS in Lake
County. Ohio submitted its plan to EPA
on April 3, 2015 and supplemented it
on October 13, 2015, and on March 13,
2017. On August 21, 2018 (83 FR
42235), EPA proposed to find that Ohio
appropriately demonstrated that its plan
will provide for attainment of the SO2
NAAQS in Lake County by the
applicable attainment date and that the
plan meets the other applicable
requirements of the CAA.
II. Public Comments and EPA
Responses
The comment period on EPA’s August
21, 2018 notice of proposed rulemaking
(NPRM) closed on September 20, 2018.
EPA received one adverse public
comment from the Sierra Club and one
public comment which was not relevant
to the proposed action. The adverse
comment and EPA’s response are
described below. In the following
discussion, EPA will refer to the Sierra
Club as ‘‘the commenter.’’ ‘‘The
Painesville plant’’ refers to the
Painesville Municipal Electric Plant in
Lake County. The ‘‘April 2014
guidance’’ refers to EPA’s April 23, 2014
recommended guidance for meeting the
statutory requirements in SO2
nonattainment area SIPs, entitled,
‘‘Guidance for 1-Hour SO2
Nonattainment Area SIP Submissions,’’
available at https://www.epa.gov/sites/
production/files/2016-06/documents/
20140423guidance_nonattainment_
sip.pdf.
Comment: The commenter stated that
short-term exposure to SO2 for as little
as five minutes has significant health
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impacts, and that EPA changed the SO2
NAAQS to a shorter-term form to
address these health impacts. The
commenter said that emission limits
with an averaging period longer than
one hour are highly unlikely to be able
to protect the 1-hour NAAQS. The
commenter said that EPA cannot rely on
a 30-day emission limit for the
Painesville plant to assure compliance
with a 1-hour air quality standard. The
commenter believes that EPA should
not approve Ohio’s nonattainment plan
until Ohio develops a 1-hour emission
limit for the Painesville plant that
protects public health.
EPA Response: The health effects
information provided by the
commenter, which was addressed in
EPA’s promulgation of the 2010 SO2
NAAQS, is not in dispute in this
rulemaking. This rulemaking instead
addresses whether Ohio’s plan is
adequate to meet the NAAQS.
EPA disagrees with the commenter’s
statement that emission limits with an
averaging period longer than one hour
are highly unlikely to be able to protect
the 1-hour NAAQS. EPA believes as a
general matter that properly set longer
term average limits are comparably
effective in providing for attainment of
the 1-hour SO2 standard as 1-hour
limits. EPA provided a more complete
rationale for this belief in the August 21,
2018 NPRM for the Lake County SO2
SIP, including a summary of analyses
described in EPA’s guidance that
support a conclusion that the
distribution of emissions that can be
expected in compliance with a properly
set longer term average limit is likely to
yield better overall air quality than
constant hourly emissions set at a level
that provides for attainment. EPA found
that a longer term average limit which
is comparably stringent to a short-term
average limit is likely to yield
comparable air quality; and that the net
effect of allowing emissions variability
over time but requiring a lower average
emission level is that the resulting
worst-case air quality is likely to be
comparable to or better than the worstcase air quality resulting from the
corresponding higher emission limit
without variability.
It is useful here to distinguish
between exceedances and violations.
The term ‘‘exceedance,’’ or ‘‘exceedance
of the level of the NAAQS,’’ is used to
mean a single occasion on which the
ambient SO2 concentration exceeds 75
parts per billion (ppb). The term
‘‘violation,’’ in contrast, means that a
sufficient number and magnitude of
exceedances has occurred to violate the
NAAQS, i.e., that the 3-year average of
the 99th percentile daily maximum 1-
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hour SO2 concentrations is above 75
ppb.
Any accounting of whether a 30-day
average limit provides for attainment
must consider factors that reduce the
likelihood of exceedances of the
NAAQS level as well as factors that
create risk of additional exceedances. To
facilitate this analysis, EPA used the
concept of a critical emission value
(CEV) for the SO2-emitting facilities
which are being addressed in a
nonattainment SIP. The CEV is the
continuous 1-hour emission rate which
is expected to provide for the average
annual 99th percentile maximum daily
1-hour concentration to be at or below
75 ppb, which in a typical year means
that fewer than four days have
maximum hourly ambient SO2
concentrations exceeding 75 ppb.
EPA recognizes that a 30-day limit
can allow occasions in which emissions
exceed the CEV, and such occasions
yield the possibility of exceedances of
the NAAQS level occurring that would
not be expected if emissions were
always at the CEV. At the same time, the
establishment of the 30-day limit below
the CEV means that emissions must
routinely be lower than they would be
required to be with a 1-hour emission
limit at the CEV. On those critical
modeled days in which emissions at the
CEV are expected to result in
concentrations exceeding 75 ppb,
emissions below the CEV may well
result in concentrations below 75 ppb.
Requiring emissions on average to be
below the CEV introduces significant
chances that emissions will be below
the CEV on critical days, so that such a
requirement creates significant chances
that air quality would be better than 75
ppb on days that, with emissions at the
CEV, would have exceeded 75 ppb.
The August 21, 2018 NPRM provides
an illustrative example of the effect that
application of a limit with an averaging
time longer than 1 hour can have on air
quality. This example illustrates both:
(1) The possibility of elevated emissions
(emissions above the CEV) causing
exceedances of the NAAQS level not
expected with emissions at or below the
CEV and (2) the possibility that the
requirement for routinely lower
emissions would result in avoiding
exceedances of the NAAQS level that
would be expected with emissions at
the CEV. In this example, moving from
a 1-hour limit to a 30-day average limit
results in one day that exceeds 75 ppb
that would otherwise be below 75 ppb,
one day that is below 75 ppb that would
otherwise be above 75 ppb, and one day
that is below 75 ppb that would
otherwise be at 75 ppb. In net, the 99th
percentile of the 30-day average limit
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scenario is lower than that of the 1-hour
limit scenario, with a design value of
67.5 ppb rather than 75 ppb. Stated
more generally, this example illustrates
several points: (1) The variations in
emissions that are accounted for with a
longer term average limit can yield
higher concentrations on some days and
lower concentrations on other days, as
determined by the factors influencing
dispersion on each day, (2) one must
account for both possibilities, and (3)
accounting for both effects can yield the
conclusion that a properly set longer
term average limit can provide as good
or better air quality than allowing
constant emissions at a higher level.
The commenter does not address
EPA’s full rationale for concluding that
properly set 30-day average limits are a
suitable basis for providing for
attainment of the 1-hour SO2 standard.
Instead, the commenter merely notes the
possibility that air quality could be
worse with a 30-day average limit than
with a 1-hour limit because the longerterm limit appears to allow emissions to
exceed the level of an acceptable 1-hour
limit. The commenter makes no
acknowledgement of the possibility that
a properly adjusted 30-day average limit
can avoid some exceedances of the
NAAQS level that would be expected to
occur with emissions allowed always to
be at the CEV. Consequently, the
commenter does not acknowledge or
address the occasions in which the
longer-term limit requires better air
quality, which is a key element of EPA’s
rationale for concluding that the net
effect of limiting longer term average
emissions to a downward adjusted level
can be comparably effective in
providing for attainment as limiting
1-hour emissions to the level of the
CEV.
EPA does not agree that in all cases
it must disapprove plans which use
longer-term limits, and instead require
1-hour emission limits. After reviewing
Ohio’s submittal, EPA finds that the
limits established for the Painesville
plant provide a suitable alternative to
establishing 1-hour average emission
limits for this source. Ohio’s limits for
the Painesville plant were developed in
accordance with EPA’s April 2014
guidance, with an appropriate
downward adjustment from the CEV
found in Ohio’s modeling analysis. EPA
is satisfied that the Painesville plant’s
30-day emission limits are therefore
comparable in stringency to the 1-hour
CEV. The Painesville plant’s boilers are
also subject to a requirement for a
reduction in coal sulfur content, a
separate 24-hour cap on their total
operating rate, and an additional
restriction to ten percent of their annual
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capacity in accordance with the Limited
Use definition in the Boiler MACT 1
rule.
In addition, the 2015 closure of the
FirstEnergy Generation, LLC, Eastlake
Plant has provided additional SO2
emission reductions which were not
credited in the Lake County modeling
analysis. These reductions help
supplement the effectiveness of Ohio’s
planned reductions at the Painesville
plant to bring Lake County into
attainment of the 2010 SO2 NAAQS and
maintain the standards in future.
EPA believes that Ohio’s Lake County
nonattainment plan as a whole is
sufficient to protect and maintain the
2010 SO2 NAAQS.
Comment: The commenter asserts that
the limits are ‘‘not comparable in
stringency to the hourly emission rates
modeled by Ohio in its attainment
demonstration.’’
EPA Response: The commenter does
not dispute EPA’s rationale for
concluding that Ohio’s 30-day average
limits for the Painesville plant are
comparably stringent to 1-hour limits at
the level Ohio modeled, nor does the
commenter provide a basis for its
assertion that Ohio’s limits are not
comparably stringent. EPA’s guidance
provides a recommended approach for
determining the ratio between 30-day
average levels and 1-hour levels,
determined at the 99th percentile level,
which yields an adjustment factor that
seeks to quantify the effect of using the
longer averaging time on the stringency
of the limit and thus presumptively
expresses the degree of adjustment to be
applied to a 1-hour emission limit to
determine a comparably stringent 30day average limit.
EPA concurred with Ohio’s decision
to apply the national average of such
adjustment factors, as given in
Appendix D of EPA’s April 2014
guidance. In absence of a rationale for
changing its views, EPA continues to
believe that the 30-day average limits
adopted by Ohio are comparably
stringent to 1-hour limits at the level
Ohio modeled.
Comment: The commenter said that
air quality conditions can be rendered
unsafe by as few as four hours of
elevated emissions over the course of
the year, making an emission limit with
an averaging period of longer than one
hour unlikely to be able to protect this
short-term standard. The commenter
argued that spikes in emissions from the
Painesville plant could cause short-term
1 Information about the boiler MACT is available
at https://www.epa.gov/stationary-sources-air
pollution/industrial-commercial-and-institutionalboilers-and-process-heaters.
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elevations in ambient SO2 levels
sufficient to violate the NAAQS while
nonetheless averaging out over longer
periods such that the 30-day average
permit limit is ‘‘complied’’ with.
EPA Response: Again, proper
accounting of the air quality
consequences of applying a 30-day
average limit cannot be limited to
consideration of the possibility of
additional exceedances of 75 ppb on
days with emissions above the CEV; one
must additionally consider the
likelihood of effects in the other
direction, i.e., that requiring lower
emissions on average (and on most
occasions) might result in avoiding
exceedances of the NAAQS level that
would occur with emissions at the CEV.
As discussed above, the NPRM provides
an example that illustrates this
principle.
In addition, for several reasons, EPA
disagrees with the commenter’s
implication that any short-term occasion
of elevated emissions (e.g., emissions
above the CEV) creates an unacceptable
risk of additional exceedances of the
NAAQS level that would result in actual
violation of the standard. First, the
occurrence of an hour with emissions
above the CEV is unlikely on its own to
lead to a concentration above the level
of the NAAQS. The CEV is identified as
an emission level which will protect
against NAAQS violations, considering
the full range of local meteorological
conditions. The analyses which identify
the CEV show that ambient air
concentrations would be well below
exceedance levels in much of the
modeling domain, and for most hours.
Episodes of elevated emissions cause
significantly elevated concentrations
only on a limited number of days per
year when meteorological conditions
favor high concentrations. As a result,
any single episode of elevated emissions
cannot be assumed to cause an
exceedance of 75 ppb, and in fact the
risk of such an event, while nonzero, is
quite low. Furthermore, even if multiple
occurrences of elevated emissions do
occur at times with meteorology
conducive to high concentrations, these
occasions are likely to involve different
wind directions, resulting in the
elevated concentrations occurring at
different locations. Therefore, from the
perspective that air quality is evaluated
at individual locations, and a violation
occurs only if any single location
observes an excessive net number of
exceedances, it is especially unlikely
that isolated occurrences of elevated
emissions (particularly in a scenario
with emissions on most occasions being
well below the CEV) would result in
violations at any location.
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Second, EPA disagrees with the
apparent view that any risk of an event
in which elevated emissions causes
otherwise unexpected exceedances of 75
ppb is an unacceptable risk. While use
of a limit based on a long-term average
increases the risk of elevated
concentrations on a small number of
days, the establishment of the limit at a
reduced level means that most days will
have a reduced risk of elevated
concentrations. Since the pertinent
question is whether Ohio’s plan
provides for attainment, EPA must
address the net effect of applying a longterm average, not just considering those
factors that increase the likelihood of
exceedances of 75 ppb or just
considering those factors that reduce the
likelihood of such exceedances.
Examining the net probabilities of
elevated emissions occurring
simultaneously with meteorology
conducive to exceedances, and of
reduced emissions occurring on
occasions that would have experienced
exceedances of the standard without
that emission reduction, suggests that
the net effects cannot be assessed
without a complicated analysis. A more
useful framework for considering these
questions is to focus, for any particular
location, on those hours where the
meteorology is conducive to having high
concentrations at that location.
Consider, for example, the likely
magnitude of emissions during the
pertinent hours for a source that is
complying with a long-term limit that
reflects a 30 percent downward
adjustment. During the pertinent hours,
the source is quite unlikely to be
emitting more than the CEV (a
probability on the order of 1 percent)
and is much more likely to be emitting
at or below 30 percent below the CEV.
This perspective better frames the
question of the net effect of having
variable emissions occasionally
exceeding the CEV but requiring
emissions to average well below the
CEV as compared to allowing emissions
always to be at the CEV.
EPA believes that if emissions at
critical times are suitably unlikely to
exceed the CEV and are suitably likely
to be well below the CEV, the net effect
is to provide adequately for attainment.
As discussed in the NPRM, EPA has
conducted analyses to evaluate the
extent to which longer-term average
limits with comparable stringency to 1hour limits at the critical emission value
can provide for attainment. EPA finds
that a comparably stringent limit
provides a sufficient constraint on the
frequency and magnitude of occurrences
of elevated emissions such that this
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control strategy will reasonably provide
for attainment.
As stated in appendix B of EPA’s
April 2014 guidance, the Agency
acknowledges that even with an
adjustment to provide comparable
stringency, a source complying with a
longer-term average emission limit
could possibly have hourly emissions
which occasionally exceed the critical
emission value. In order to assure that
SO2 emission sources will maintain the
NAAQS while using longer-term
average limits, EPA’s guidance
recommends that 30-day average SO2
limits be set at a level below the level
that would be expected to be protective
of the SO2 NAAQS as a 1-hour SO2
limit. A facility in compliance with the
30-day limit could therefore have
occasional spikes of higher
concentration, but the majority of its
hourly impacts must be as low as or
lower than those of a source which is
limited at the critical emission value
level. As was stated in the NPRM, EPA’s
statistical analyses of SO2 emissions
data showed that a comparably stringent
30-day average limit is likely to result in
fewer exceedances and better air quality
than would occur with 1-hour emissions
at the critical emission value.
Comment: The commenter said that
past EPA SO2 policy (1994) definitively
stated that ‘‘EPA will not approve an
SO2 SIP with emission limitations based
on 30-day average, unless the SIP also
contains short-term limits established
by an approved dispersion modeling
analysis.’’ The commenter also cited
past actions, including a 1986
memorandum regarding a specific
proposed facility, in which EPA
determined that compliance with a 30day rolling average emission limit under
NSPS Subpart Da does not adequately
demonstrate compliance with shortterm NAAQS and PSD increments,
regardless of sulfur variability.
EPA Response: In this action, EPA is
not changing its position regarding the
1-hour emissions limitations to which
other facilities, as cited by the
commenter, are subject. However, the
examples that the commenter cites
predate the release of EPA’s April 2014
guidance. They reflect EPA’s policy for
implementing the NAAQS before EPA
addressed the question of whether it
might be possible to devise an effective
attainment plan using an emission limit
with an averaging period longer than
that of the NAAQS, given appropriate
adjustments to make the limit
comparably stringent to a short-term
emission rate that would ensure
attainment of the SO2 NAAQS. EPA
developed the April 2014 guidance after
a lengthy stakeholder outreach process
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regarding implementation strategies for
the 2010 SO2 NAAQS. As the April
2014 guidance was the first instance in
which the Agency provided direct
guidance for considering adjusted longterm average limits for a short-term
standard, EPA does not consider the
earlier documents to countermand the
April 2014 guidance on this issue.
EPA’s April 2014 guidance
acknowledges that EPA had previously
recommended that averaging times in
SIP emission limits should not exceed
the averaging time of the applicable
NAAQS. However, the April 2014
guidance expresses EPA’s finding that
control strategies involving limits with
averaging times of up to 30 days can
provide for attainment of the 2010 SO2
NAAQS, where the limits have been set
at levels expected to be comparably
stringent to shorter-term limits. As
stated in the August 21, 2018 NPRM,
EPA considered Ohio’s control strategy
for the Painesville plant and found that
the limits in Ohio Administrative Code
Chapter 3745–18 (OAC 3745–18) met
EPA’s guidelines for acceptable
emission limits based on a 30-day
averaging time.
Comment: The commenter stated that
a 30-day averaging time is the same as
a 720-hour averaging period rolling on
a daily basis, and ‘‘it seems impossible
to derive a 720-hour average limit that
would ensure hourly emissions of SO2
are limited to the extent necessary to
protect the 1-hour average SO2 NAAQS,
unless it was shown through air
dispersion modeling that the maximum
uncontrolled hourly emissions from a
source would not exceed the NAAQS.’’
EPA Response: The compliance
calculations for the limits applicable to
the Painesville plant units would be
720-hour averages when the unit
operates in each of those 720 hours.
Hours in which the unit is not operating
are not included in the calculation, to
focus the compliance test on how well
the facility’s emissions are controlled
during operational hours.
EPA’s April 2014 guidance provides
the results of analyses which
demonstrate that limits based on
periods of as long as 30 days (720 hours)
can, in many cases, be reasonably
considered to provide for attainment of
the 2010 SO2 NAAQS. When a 30-day
emission limit is set sufficiently lower
than the 1-hour emission limit which
the modeling analysis indicated would
conservatively provide for attainment,
the numerically lower 30-day limit
would also be expected to provide for
attainment. In accordance with EPA
guidance, Ohio conducted modeling to
determine the CEV, i.e., the emission
rate that, if emitted continuously, would
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result in attainment. Ohio then
established 30-day average limits that
are comparably stringent to the 1-hour
limits it otherwise would have
established. EPA agrees with Ohio that
these limits can be expected to provide
comparable air quality as the
corresponding 1-hour limits would, and
EPA considers the 30-day average limits
to satisfy the requirement to provide for
attainment.
EPA does not agree with the
commenter that the application of a
longer term average limit requires
determining the unit’s maximum
uncontrolled emission rate or a
maximum 1-hour emission rate that
might occur in compliance with a longer
term average emission limit, or that
modeling must be conducted to show
that such emission rates do not cause
NAAQS violations. The analysis that the
commenter proposes would not take
proper account of the impact of variable
emissions within the longer-term limit.
In particular, while such an analysis
would assess potential additional
exceedances of the NAAQS level on
occasions with elevated emissions, such
an analysis would fail to reflect the
improved air quality on days with lower
emissions. Since compliance with a
downward adjusted long term average
limit necessarily requires any occasions
of elevated emissions to be
accompanied by occasions of lower than
average emissions, the commenter’s
proposed analysis is inadequate for
assessing the net effects of emissions
sometimes being higher but more often
being lower than the CEV.
Comment: The commenter states that
Ohio’s approach is inconsistent with
EPA’s Guideline on Air Quality Models,
which in Table 8–1 ‘‘requires modeling
for short term (<= 24 hours) NAAQS be
based on the allowable emissions over
the averaging time of the NAAQS. Yet,
the maximum allowable hourly
emission rate is difficult to predict from
a 30-day average limit for an emissions
unit.’’
EPA Response: EPA’s 2014 guidance
for SO2 SIPs directly addresses the
comment regarding Table 8–1. Page A–
79 of the guidance states:
An important caveat regarding Table 8–1 of
Appendix W is that this guidance is oriented
toward short term emission limits (e.g., 1hour emission limits), as recommended in
previous guidance. Current guidance,
providing for use of longer term emission
limits, provides that after the state
determines the 1-hour limit that would be
necessary to provide for attainment, any
longer-term limit should be established at a
level that is sufficiently lower to provide
comparable stringency. Thus, in cases where
a state wishes to apply a longer term average
limit, the attainment analysis would be based
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3989
not on the level of the longer-term limit but
rather on the level of the corresponding 1hour emission limit that was shown in the
plan to be of comparable stringency.
Accordingly, EPA believes that Ohio has
provided an appropriate demonstration
that its 30-day average limit, set to be
comparably stringent to a 1-hour limit at
the modeled CEV, will provide for
attainment.
Comment: The commenter said that
EPA’s April 2014 guidance allows
flexibility for sources that cannot meet
the hourly rate of SO2 emissions
necessary to attain the NAAQS. The
CAA requires the implementation of all
reasonably available control measures to
provide for attainment. The commenter
said that it is reasonable for a source
such as the Painesville plant to guard
against spikes in sulfur content of fuel
and/or SO2 emissions through proper
operation of scrubbers, limiting high
sulfur coal, and testing for coal sulfur
content. The commenter believes that
the flexibility in EPA’s guidance has
allowed Ohio to propose 30-day average
limits for the Painesville plant which
fail Congress’ direction that EPA shall
provide for attainment of the NAAQS.
EPA Response: EPA believes it is
important to recognize that some
sources may have variable emissions,
for example due to variations in fuel
sulfur content and operating rate, that
can make it extremely difficult, even
with a well-designed control strategy, to
ensure in practice that stringent hourly
limits are never exceeded. The
Painesville plant is complying with the
Federal Boiler MACT rule by taking
enforceable limits on its operations to
meet the definition of a Limited Use
boiler, operating at 10% of its annual
heat input capacity. As such, the plant
will only operate intermittently, during
periods of high demand or service
interruptions. This type of operation
reflects a decrease in overall emissions
from this source.
The boiler MACT rule does not
require that Limited Use boilers install
additional control technology, because
add-on SO2 control systems require
steady-state operations for good control
efficiency and cannot reduce SO2
emissions effectively for intermittent
short-term operations. The Painesville
plant’s revised rules do require a
reduction in allowable coal sulfur
content, with coal sampling to confirm
sulfur content. Ohio EPA has
determined that the Painesville plant is
unable to use very low sulfur (Powder
River Basin) coal because of the high
cost of updating its facilities to handle
and use it for its limited operations;
because the unique characteristics of the
coal has a detrimental effect on the
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facility’s particulate matter controls; and
because of the increased risk of fire
during storage of the more volatile lowsulfur coal, which has occurred
elsewhere in Ohio with similar coal
storage and handling equipment.
EPA believes that the flexibility of the
30-day average limit is reasonable for an
intermittently-operating facility such as
the Painesville plant. As stated
previously, EPA’s analyses
demonstrated that its requirement for a
tighter limit to be used with a longerterm averaging period is likely to yield
better air quality than is required with
a comparably stringent 1-hour limit.
EPA’s April 2014 guidance states, ‘‘if
periods of hourly emissions above the
critical emission value are a rare
occurrence at a source, these periods
would be unlikely to have a significant
impact on air quality, insofar as they
would be very unlikely to occur
repeatedly at the times when the
meteorology is conducive for high
ambient concentrations of SO2.’’ The
Painesville plant’s limit, supplemented
by an additional 24-hour boiler heat
input cap and the stringent federally
enforceable limitation on the plant’s
annual boiler usage, is expected to
provide for attainment of the NAAQS in
accordance with the CAA’s
requirements.
III. What action is EPA taking?
EPA is approving Ohio’s April 3, 2015
plan, as supplemented on October 13,
2015 and on March 13, 2017, for
attaining the 2010 1-hour SO2 NAAQS
and for meeting other nonattainment
area planning requirements for the Lake
County SO2 nonattainment area. EPA is
amending the codification in 40 CFR
52.1870(e) to include the approval of
Ohio’s SO2 attainment plan for Lake
County.
In development of this plan, Ohio
amended its rules at OAC 3745–18–49
(F) (establishing new limits for the
Painesville plant), OAC 3745–18–03
(B)(9), OAC 3745–18–03 (C)(11), and
OAC 3745–18–04(D)(10) (establishing a
compliance date and other
administrative provisions), and
rescinding OAC 3745–18–49(G)
(reflecting the enforceable shutdown of
the Eastlake plant). These revisions
became effective on February 16, 2017.
EPA approved these revisions into the
SIP, as codified at 40 CFR 52.1870(c), on
October 11, 2018 (83 FR 51361), as part
of action on a broader range of OAC
Chapter 3745–18 revisions. Thus, no
additional action is necessary to
incorporate the pertinent limits into the
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SIP, and this action is limited to
concluding that Ohio has demonstrated
that these previously approved limits
provide for attainment of the SO2
NAAQS in Lake County and that Ohio
has met the other planning requirements
for this area.
IV. Statutory and Executive Order
Reviews
Under the CAA, the Administrator is
required to approve a SIP submission
that complies with the provisions of the
CAA and applicable Federal regulations.
42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions,
EPA’s role is to approve state choices,
provided that they meet the criteria of
the CAA. Accordingly, this action
merely approves state law as meeting
Federal requirements and does not
impose additional requirements beyond
those imposed by state law. For that
reason, this action:
• Is not a significant regulatory action
subject to review by the Office of
Management and Budget under
Executive Orders 12866 (58 FR 51735,
October 4, 1993) and 13563 (76 FR 3821,
January 21, 2011);
• Is not an Executive Order 13771 (82
FR 9339, February 2, 2017) regulatory
action because SIP approvals are
exempted under Executive Order 12866;
• Does not impose an information
collection burden under the provisions
of the Paperwork Reduction Act (44
U.S.C. 3501 et seq.);
• Is certified as not having a
significant economic impact on a
substantial number of small entities
under the Regulatory Flexibility Act (5
U.S.C. 601 et seq.);
• Does not contain any unfunded
mandate or significantly or uniquely
affect small governments, as described
in the Unfunded Mandates Reform Act
of 1995 (Pub. L. 104–4);
• Does not have Federalism
implications as specified in Executive
Order 13132 (64 FR 43255, August 10,
1999);
• Is not an economically significant
regulatory action based on health or
safety risks subject to Executive Order
13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory action
subject to Executive Order 13211 (66 FR
28355, May 22, 2001);
• Is not subject to requirements of
Section 12(d) of the National
Technology Transfer and Advancement
Act of 1995 (15 U.S.C. 272 note) because
application of those requirements would
be inconsistent with the CAA; and
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Sfmt 4700
• Does not provide EPA with the
discretionary authority to address, as
appropriate, disproportionate human
health or environmental effects, using
practicable and legally permissible
methods, under Executive Order 12898
(59 FR 7629, February 16, 1994).
In addition, the SIP is not approved
to apply on any Indian reservation land
or in any other area where EPA or an
Indian tribe has demonstrated that a
tribe has jurisdiction. In those areas of
Indian country, the rule does not have
tribal implications and will not impose
substantial direct costs on tribal
governments or preempt tribal law as
specified by Executive Order 13175 (65
FR 67249, November 9, 2000).
The Congressional Review Act, 5
U.S.C. 801 et seq., as added by the Small
Business Regulatory Enforcement
Fairness Act of 1996, generally provides
that before a rule may take effect, the
agency promulgating the rule must
submit a rule report, which includes a
copy of the rule, to each House of the
Congress and to the Comptroller General
of the United States. EPA will submit a
report containing this action and other
required information to the U.S. Senate,
the U.S. House of Representatives, and
the Comptroller General of the United
States prior to publication of the rule in
the Federal Register. A major rule
cannot take effect until 60 days after it
is published in the Federal Register.
This action is not a ‘‘major rule’’ as
defined by 5 U.S.C. 804(2).
Under section 307(b)(1) of the CAA,
petitions for judicial review of this
action must be filed in the United States
Court of Appeals for the appropriate
circuit by April 15, 2019. Filing a
petition for reconsideration by the
Administrator of this final rule does not
affect the finality of this action for the
purposes of judicial review nor does it
extend the time within which a petition
for judicial review may be filed, and
shall not postpone the effectiveness of
such rule or action. This action may not
be challenged later in proceedings to
enforce its requirements. (See section
307(b)(2).)
List of Subjects in 40 CFR Part 52
Environmental protection, Air
pollution control, Incorporation by
reference, Intergovernmental relations,
Reporting and recordkeeping
requirements, Sulfur oxides.
Dated: January 29, 2019.
Cathy Stepp,
Regional Administrator, Region 5.
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Authority: 42 U.S.C. 7401 et seq.
40 CFR part 52 is amended as follows:
§ 52.1870
2. In § 52.1870, the table in paragraph
(e) is amended by adding an entry for
‘‘SO2 (2010)’’ after the entry for ‘‘PM2.5
(2012)’’ under the heading ‘‘Summary of
Criteria Pollutant Attainment Plans’’ to
read as follows:
■
PART 52—APPROVAL AND
PROMULGATION OF
IMPLEMENTATION PLANS
1. The authority citation for part 52
continues to read as follows:
■
*
Identification of plan.
*
*
(e) * * *
*
*
EPA-APPROVED OHIO NONREGULATORY AND QUASI-REGULATORY PROVISIONS
Title
Applicable
geographical or
non-attainment
area
*
*
State date
EPA approval
*
Comments
*
*
*
*
Summary of Criteria Pollutant Attainment Plans
*
SO2 (2010) ..........
*
Lake County ........
*
*
*
2/16/2017
*
[FR Doc. 2019–02210 Filed 2–13–19; 8:45 am]
BILLING CODE 6560–50–P
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R04–OAR–2018–0531; FRL–9989–38–
Region 4]
Air Plan Approval; North Carolina;
Ozone NAAQS Update
Environmental Protection
Agency (EPA).
ACTION: Final rule.
AGENCY:
The Environmental Protection
Agency (EPA) is approving a State
Implementation Plan (SIP) revision
submitted by the State of North Carolina
through the North Carolina Division of
Air Quality (NCDAQ) with a letter dated
March 21, 2018. The SIP submittal
includes changes to the State’s air
quality rules for ozone to be consistent
with the National Ambient Air Quality
Standards (NAAQS). EPA is approving
these provisions of the SIP revision
because the State has demonstrated that
these changes are consistent with the
Clean Air Act (CAA or Act) and federal
regulations.
DATES: This rule is effective March 18,
2019.
ADDRESSES: EPA has established a
docket for this action under Docket
Identification No. EPA–R04–OAR–
2018–0531. All documents in the docket
are listed on the www.regulations.gov
SUMMARY:
VerDate Sep<11>2014
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*
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Register citation].
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*
*
*
EPA is approving the following plan elements: The emission inventory; the demonstration of attainment; and revised emission limits as meeting RACM requirements.
*
*
website. Although listed in the index,
some information is not publicly
available, i.e., Confidential Business
Information or other information whose
disclosure is restricted by statute.
Certain other material, such as
copyrighted material, is not placed on
the internet and will be publicly
available only in hard copy form.
Publicly available docket materials are
available either electronically through
www.regulations.gov or in hard copy at
the Air Regulatory Management Section,
Air Planning and Implementation
Branch, Air, Pesticides and Toxics
Management Division, U.S.
Environmental Protection Agency,
Region 4, 61 Forsyth Street SW, Atlanta,
Georgia 30303–8960. EPA requests that
if at all possible, you contact the person
listed in the FOR FURTHER INFORMATION
CONTACT section to schedule your
inspection. The Regional Office’s
official hours of business are Monday
through Friday 8:30 a.m. to 4:30 p.m.,
excluding Federal holidays.
FOR FURTHER INFORMATION CONTACT:
Tiereny Bell, Air Regulatory
Management Section, Air Planning and
Implementation Branch, Air, Pesticides
and Toxics Management Division, U.S.
Environmental Protection Agency,
Region 4, 61 Forsyth Street SW, Atlanta,
Georgia 30303–8960. The telephone
number is (404) 562–9088. Ms. Bell can
also be reached via electronic mail at
bell.tiereny@epa.gov.
SUPPLEMENTARY INFORMATION:
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*
*
I. Background
Sections 108 and 109 of the CAA
govern the establishment, review, and
revision, as appropriate, of the NAAQS
to protect public health and welfare.
The CAA requires periodic review of the
air quality criteria—the science upon
which the standards are based—and the
standards themselves. EPA’s regulatory
provisions that govern the NAAQS are
found at 40 CFR 50—National Primary
and Secondary Ambient Air Quality
Standards. In this rulemaking, EPA is
approving revisions to the North
Carolina air quality rules addressing
Rule 15A NCAC 02D .0405, Ozone, in
the North Carolina SIP.1 EPA notes that
the cover letter was dated March 21,
2018.2 Under Subchapter 2D, Section
.0405 is amended by updating air
quality standards to reflect the most
recent ozone NAAQS as well as making
textual modifications in the following
manner: Removing 0.075 parts per
million (ppm) and replacing it with
0.070 ppm; deleting ‘‘8-hour’’ and
replacing it with ‘‘eight-hour’’; deleting
the word ‘‘is’’ and replacing it with
‘‘shall be’’ and later ‘‘shall be deemed’’;
and deleting Appendix P, which
referenced the 2008 Ozone Standard,
and replacing it with Appendix U,
which references the 2015 Ozone
Standard. The SIP submission amending
1 In the table of North Carolina regulations
federally-approved into the SIP at 40 CFR
52.1770(c), 15A NCAC 02D is referred to as
‘‘Subchapter 2D Air Pollution Control
Requirements.’’
2 The submittal was received on April 4, 2018.
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Agencies
[Federal Register Volume 84, Number 31 (Thursday, February 14, 2019)]
[Rules and Regulations]
[Pages 3986-3991]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-02210]
[[Page 3986]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R05-OAR-2015-0699; FRL-9989-48-Region 5]
Air Plan Approval; Ohio; Attainment Plan for the Lake County
SO2 Nonattainment Area
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is approving, under
the Clean Air Act (CAA), Ohio's plan for attaining the 1-hour sulfur
dioxide (SO2) primary national ambient air quality standard
(NAAQS) in the Lake County SO2 nonattainment area. EPA
proposed to approve Ohio's Lake County plan as a revision to Ohio's
SO2 State Implementation Plan (SIP) on August 21, 2018. EPA
received public comments on the proposed rulemaking and is providing
responses to the comments below.
DATES: This final rule is effective on March 18, 2019.
ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-R05-OAR-2015-0699. All documents in the docket are listed on
the www.regulations.gov website. Although listed in the index, some
information is not publicly available, i.e., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the internet and will be publicly available only in hard
copy form. Publicly available docket materials are available either
through www.regulations.gov or at the Environmental Protection Agency,
Region 5, Air and Radiation Division, 77 West Jackson Boulevard,
Chicago, Illinois 60604. This facility is open from 8:30 a.m. to 4:30
p.m., Monday through Friday, excluding Federal holidays. We recommend
that you telephone Mary Portanova, Environmental Engineer, at (312)
353-5954 before visiting the Region 5 office.
FOR FURTHER INFORMATION CONTACT: Mary Portanova, Environmental
Engineer, Control Strategies Section, Air Programs Branch (AR-18J),
Environmental Protection Agency, Region 5, 77 West Jackson Boulevard,
Chicago, Illinois 60604, (312) 353-5954, portanova.mary@epa.gov.
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA. Ohio's nonattainment SIP
submittal of April 3, 2015, supplemented on October 13, 2015 and on
March 13, 2017, addressed Ohio's Lake County, Muskingum River, and
Steubenville OH-WV SO2 nonattainment areas. This final
action addresses only the Lake County portion of Ohio's nonattainment
SIP submittal. The Muskingum River and Steubenville portions of Ohio's
submittal will be addressed in future action.
This Supplementary Information section is arranged as follows:
I. Background
II. Public Comments and EPA Responses
III. What action is EPA taking?
IV. Statutory and Executive Order Reviews
I. Background
Lake County, Ohio, was designated nonattainment for the 2010 1-hour
primary SO2 NAAQS on August 5, 2013 (78 FR 47191). As
required by the CAA, Ohio developed a plan to provide for attainment of
the SO2 NAAQS in Lake County. Ohio submitted its plan to EPA
on April 3, 2015 and supplemented it on October 13, 2015, and on March
13, 2017. On August 21, 2018 (83 FR 42235), EPA proposed to find that
Ohio appropriately demonstrated that its plan will provide for
attainment of the SO2 NAAQS in Lake County by the applicable
attainment date and that the plan meets the other applicable
requirements of the CAA.
II. Public Comments and EPA Responses
The comment period on EPA's August 21, 2018 notice of proposed
rulemaking (NPRM) closed on September 20, 2018. EPA received one
adverse public comment from the Sierra Club and one public comment
which was not relevant to the proposed action. The adverse comment and
EPA's response are described below. In the following discussion, EPA
will refer to the Sierra Club as ``the commenter.'' ``The Painesville
plant'' refers to the Painesville Municipal Electric Plant in Lake
County. The ``April 2014 guidance'' refers to EPA's April 23, 2014
recommended guidance for meeting the statutory requirements in
SO2 nonattainment area SIPs, entitled, ``Guidance for 1-Hour
SO2 Nonattainment Area SIP Submissions,'' available at
https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
Comment: The commenter stated that short-term exposure to
SO2 for as little as five minutes has significant health
impacts, and that EPA changed the SO2 NAAQS to a shorter-
term form to address these health impacts. The commenter said that
emission limits with an averaging period longer than one hour are
highly unlikely to be able to protect the 1-hour NAAQS. The commenter
said that EPA cannot rely on a 30-day emission limit for the
Painesville plant to assure compliance with a 1-hour air quality
standard. The commenter believes that EPA should not approve Ohio's
nonattainment plan until Ohio develops a 1-hour emission limit for the
Painesville plant that protects public health.
EPA Response: The health effects information provided by the
commenter, which was addressed in EPA's promulgation of the 2010
SO2 NAAQS, is not in dispute in this rulemaking. This
rulemaking instead addresses whether Ohio's plan is adequate to meet
the NAAQS.
EPA disagrees with the commenter's statement that emission limits
with an averaging period longer than one hour are highly unlikely to be
able to protect the 1-hour NAAQS. EPA believes as a general matter that
properly set longer term average limits are comparably effective in
providing for attainment of the 1-hour SO2 standard as 1-
hour limits. EPA provided a more complete rationale for this belief in
the August 21, 2018 NPRM for the Lake County SO2 SIP,
including a summary of analyses described in EPA's guidance that
support a conclusion that the distribution of emissions that can be
expected in compliance with a properly set longer term average limit is
likely to yield better overall air quality than constant hourly
emissions set at a level that provides for attainment. EPA found that a
longer term average limit which is comparably stringent to a short-term
average limit is likely to yield comparable air quality; and that the
net effect of allowing emissions variability over time but requiring a
lower average emission level is that the resulting worst-case air
quality is likely to be comparable to or better than the worst-case air
quality resulting from the corresponding higher emission limit without
variability.
It is useful here to distinguish between exceedances and
violations. The term ``exceedance,'' or ``exceedance of the level of
the NAAQS,'' is used to mean a single occasion on which the ambient
SO2 concentration exceeds 75 parts per billion (ppb). The
term ``violation,'' in contrast, means that a sufficient number and
magnitude of exceedances has occurred to violate the NAAQS, i.e., that
the 3-year average of the 99th percentile daily maximum 1-
[[Page 3987]]
hour SO2 concentrations is above 75 ppb.
Any accounting of whether a 30-day average limit provides for
attainment must consider factors that reduce the likelihood of
exceedances of the NAAQS level as well as factors that create risk of
additional exceedances. To facilitate this analysis, EPA used the
concept of a critical emission value (CEV) for the SO2-
emitting facilities which are being addressed in a nonattainment SIP.
The CEV is the continuous 1-hour emission rate which is expected to
provide for the average annual 99th percentile maximum daily 1-hour
concentration to be at or below 75 ppb, which in a typical year means
that fewer than four days have maximum hourly ambient SO2
concentrations exceeding 75 ppb.
EPA recognizes that a 30-day limit can allow occasions in which
emissions exceed the CEV, and such occasions yield the possibility of
exceedances of the NAAQS level occurring that would not be expected if
emissions were always at the CEV. At the same time, the establishment
of the 30-day limit below the CEV means that emissions must routinely
be lower than they would be required to be with a 1-hour emission limit
at the CEV. On those critical modeled days in which emissions at the
CEV are expected to result in concentrations exceeding 75 ppb,
emissions below the CEV may well result in concentrations below 75 ppb.
Requiring emissions on average to be below the CEV introduces
significant chances that emissions will be below the CEV on critical
days, so that such a requirement creates significant chances that air
quality would be better than 75 ppb on days that, with emissions at the
CEV, would have exceeded 75 ppb.
The August 21, 2018 NPRM provides an illustrative example of the
effect that application of a limit with an averaging time longer than 1
hour can have on air quality. This example illustrates both: (1) The
possibility of elevated emissions (emissions above the CEV) causing
exceedances of the NAAQS level not expected with emissions at or below
the CEV and (2) the possibility that the requirement for routinely
lower emissions would result in avoiding exceedances of the NAAQS level
that would be expected with emissions at the CEV. In this example,
moving from a 1-hour limit to a 30-day average limit results in one day
that exceeds 75 ppb that would otherwise be below 75 ppb, one day that
is below 75 ppb that would otherwise be above 75 ppb, and one day that
is below 75 ppb that would otherwise be at 75 ppb. In net, the 99th
percentile of the 30-day average limit scenario is lower than that of
the 1-hour limit scenario, with a design value of 67.5 ppb rather than
75 ppb. Stated more generally, this example illustrates several points:
(1) The variations in emissions that are accounted for with a longer
term average limit can yield higher concentrations on some days and
lower concentrations on other days, as determined by the factors
influencing dispersion on each day, (2) one must account for both
possibilities, and (3) accounting for both effects can yield the
conclusion that a properly set longer term average limit can provide as
good or better air quality than allowing constant emissions at a higher
level.
The commenter does not address EPA's full rationale for concluding
that properly set 30-day average limits are a suitable basis for
providing for attainment of the 1-hour SO2 standard.
Instead, the commenter merely notes the possibility that air quality
could be worse with a 30-day average limit than with a 1-hour limit
because the longer-term limit appears to allow emissions to exceed the
level of an acceptable 1-hour limit. The commenter makes no
acknowledgement of the possibility that a properly adjusted 30-day
average limit can avoid some exceedances of the NAAQS level that would
be expected to occur with emissions allowed always to be at the CEV.
Consequently, the commenter does not acknowledge or address the
occasions in which the longer-term limit requires better air quality,
which is a key element of EPA's rationale for concluding that the net
effect of limiting longer term average emissions to a downward adjusted
level can be comparably effective in providing for attainment as
limiting 1-hour emissions to the level of the CEV.
EPA does not agree that in all cases it must disapprove plans which
use longer-term limits, and instead require 1-hour emission limits.
After reviewing Ohio's submittal, EPA finds that the limits established
for the Painesville plant provide a suitable alternative to
establishing 1-hour average emission limits for this source. Ohio's
limits for the Painesville plant were developed in accordance with
EPA's April 2014 guidance, with an appropriate downward adjustment from
the CEV found in Ohio's modeling analysis. EPA is satisfied that the
Painesville plant's 30-day emission limits are therefore comparable in
stringency to the 1-hour CEV. The Painesville plant's boilers are also
subject to a requirement for a reduction in coal sulfur content, a
separate 24-hour cap on their total operating rate, and an additional
restriction to ten percent of their annual capacity in accordance with
the Limited Use definition in the Boiler MACT \1\ rule.
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\1\ Information about the boiler MACT is available at https://www.epa.gov/stationary-sources-airpollution/industrial-commercial-and-institutional-boilers-and-process-heaters.
---------------------------------------------------------------------------
In addition, the 2015 closure of the FirstEnergy Generation, LLC,
Eastlake Plant has provided additional SO2 emission
reductions which were not credited in the Lake County modeling
analysis. These reductions help supplement the effectiveness of Ohio's
planned reductions at the Painesville plant to bring Lake County into
attainment of the 2010 SO2 NAAQS and maintain the standards
in future.
EPA believes that Ohio's Lake County nonattainment plan as a whole
is sufficient to protect and maintain the 2010 SO2 NAAQS.
Comment: The commenter asserts that the limits are ``not comparable
in stringency to the hourly emission rates modeled by Ohio in its
attainment demonstration.''
EPA Response: The commenter does not dispute EPA's rationale for
concluding that Ohio's 30-day average limits for the Painesville plant
are comparably stringent to 1-hour limits at the level Ohio modeled,
nor does the commenter provide a basis for its assertion that Ohio's
limits are not comparably stringent. EPA's guidance provides a
recommended approach for determining the ratio between 30-day average
levels and 1-hour levels, determined at the 99th percentile level,
which yields an adjustment factor that seeks to quantify the effect of
using the longer averaging time on the stringency of the limit and thus
presumptively expresses the degree of adjustment to be applied to a 1-
hour emission limit to determine a comparably stringent 30-day average
limit.
EPA concurred with Ohio's decision to apply the national average of
such adjustment factors, as given in Appendix D of EPA's April 2014
guidance. In absence of a rationale for changing its views, EPA
continues to believe that the 30-day average limits adopted by Ohio are
comparably stringent to 1-hour limits at the level Ohio modeled.
Comment: The commenter said that air quality conditions can be
rendered unsafe by as few as four hours of elevated emissions over the
course of the year, making an emission limit with an averaging period
of longer than one hour unlikely to be able to protect this short-term
standard. The commenter argued that spikes in emissions from the
Painesville plant could cause short-term
[[Page 3988]]
elevations in ambient SO2 levels sufficient to violate the
NAAQS while nonetheless averaging out over longer periods such that the
30-day average permit limit is ``complied'' with.
EPA Response: Again, proper accounting of the air quality
consequences of applying a 30-day average limit cannot be limited to
consideration of the possibility of additional exceedances of 75 ppb on
days with emissions above the CEV; one must additionally consider the
likelihood of effects in the other direction, i.e., that requiring
lower emissions on average (and on most occasions) might result in
avoiding exceedances of the NAAQS level that would occur with emissions
at the CEV. As discussed above, the NPRM provides an example that
illustrates this principle.
In addition, for several reasons, EPA disagrees with the
commenter's implication that any short-term occasion of elevated
emissions (e.g., emissions above the CEV) creates an unacceptable risk
of additional exceedances of the NAAQS level that would result in
actual violation of the standard. First, the occurrence of an hour with
emissions above the CEV is unlikely on its own to lead to a
concentration above the level of the NAAQS. The CEV is identified as an
emission level which will protect against NAAQS violations, considering
the full range of local meteorological conditions. The analyses which
identify the CEV show that ambient air concentrations would be well
below exceedance levels in much of the modeling domain, and for most
hours. Episodes of elevated emissions cause significantly elevated
concentrations only on a limited number of days per year when
meteorological conditions favor high concentrations. As a result, any
single episode of elevated emissions cannot be assumed to cause an
exceedance of 75 ppb, and in fact the risk of such an event, while
nonzero, is quite low. Furthermore, even if multiple occurrences of
elevated emissions do occur at times with meteorology conducive to high
concentrations, these occasions are likely to involve different wind
directions, resulting in the elevated concentrations occurring at
different locations. Therefore, from the perspective that air quality
is evaluated at individual locations, and a violation occurs only if
any single location observes an excessive net number of exceedances, it
is especially unlikely that isolated occurrences of elevated emissions
(particularly in a scenario with emissions on most occasions being well
below the CEV) would result in violations at any location.
Second, EPA disagrees with the apparent view that any risk of an
event in which elevated emissions causes otherwise unexpected
exceedances of 75 ppb is an unacceptable risk. While use of a limit
based on a long-term average increases the risk of elevated
concentrations on a small number of days, the establishment of the
limit at a reduced level means that most days will have a reduced risk
of elevated concentrations. Since the pertinent question is whether
Ohio's plan provides for attainment, EPA must address the net effect of
applying a long-term average, not just considering those factors that
increase the likelihood of exceedances of 75 ppb or just considering
those factors that reduce the likelihood of such exceedances.
Examining the net probabilities of elevated emissions occurring
simultaneously with meteorology conducive to exceedances, and of
reduced emissions occurring on occasions that would have experienced
exceedances of the standard without that emission reduction, suggests
that the net effects cannot be assessed without a complicated analysis.
A more useful framework for considering these questions is to focus,
for any particular location, on those hours where the meteorology is
conducive to having high concentrations at that location. Consider, for
example, the likely magnitude of emissions during the pertinent hours
for a source that is complying with a long-term limit that reflects a
30 percent downward adjustment. During the pertinent hours, the source
is quite unlikely to be emitting more than the CEV (a probability on
the order of 1 percent) and is much more likely to be emitting at or
below 30 percent below the CEV. This perspective better frames the
question of the net effect of having variable emissions occasionally
exceeding the CEV but requiring emissions to average well below the CEV
as compared to allowing emissions always to be at the CEV.
EPA believes that if emissions at critical times are suitably
unlikely to exceed the CEV and are suitably likely to be well below the
CEV, the net effect is to provide adequately for attainment. As
discussed in the NPRM, EPA has conducted analyses to evaluate the
extent to which longer-term average limits with comparable stringency
to 1-hour limits at the critical emission value can provide for
attainment. EPA finds that a comparably stringent limit provides a
sufficient constraint on the frequency and magnitude of occurrences of
elevated emissions such that this control strategy will reasonably
provide for attainment.
As stated in appendix B of EPA's April 2014 guidance, the Agency
acknowledges that even with an adjustment to provide comparable
stringency, a source complying with a longer-term average emission
limit could possibly have hourly emissions which occasionally exceed
the critical emission value. In order to assure that SO2
emission sources will maintain the NAAQS while using longer-term
average limits, EPA's guidance recommends that 30-day average
SO2 limits be set at a level below the level that would be
expected to be protective of the SO2 NAAQS as a 1-hour
SO2 limit. A facility in compliance with the 30-day limit
could therefore have occasional spikes of higher concentration, but the
majority of its hourly impacts must be as low as or lower than those of
a source which is limited at the critical emission value level. As was
stated in the NPRM, EPA's statistical analyses of SO2
emissions data showed that a comparably stringent 30-day average limit
is likely to result in fewer exceedances and better air quality than
would occur with 1-hour emissions at the critical emission value.
Comment: The commenter said that past EPA SO2 policy
(1994) definitively stated that ``EPA will not approve an
SO2 SIP with emission limitations based on 30-day average,
unless the SIP also contains short-term limits established by an
approved dispersion modeling analysis.'' The commenter also cited past
actions, including a 1986 memorandum regarding a specific proposed
facility, in which EPA determined that compliance with a 30-day rolling
average emission limit under NSPS Subpart Da does not adequately
demonstrate compliance with short-term NAAQS and PSD increments,
regardless of sulfur variability.
EPA Response: In this action, EPA is not changing its position
regarding the 1-hour emissions limitations to which other facilities,
as cited by the commenter, are subject. However, the examples that the
commenter cites predate the release of EPA's April 2014 guidance. They
reflect EPA's policy for implementing the NAAQS before EPA addressed
the question of whether it might be possible to devise an effective
attainment plan using an emission limit with an averaging period longer
than that of the NAAQS, given appropriate adjustments to make the limit
comparably stringent to a short-term emission rate that would ensure
attainment of the SO2 NAAQS. EPA developed the April 2014
guidance after a lengthy stakeholder outreach process
[[Page 3989]]
regarding implementation strategies for the 2010 SO2 NAAQS.
As the April 2014 guidance was the first instance in which the Agency
provided direct guidance for considering adjusted long-term average
limits for a short-term standard, EPA does not consider the earlier
documents to countermand the April 2014 guidance on this issue.
EPA's April 2014 guidance acknowledges that EPA had previously
recommended that averaging times in SIP emission limits should not
exceed the averaging time of the applicable NAAQS. However, the April
2014 guidance expresses EPA's finding that control strategies involving
limits with averaging times of up to 30 days can provide for attainment
of the 2010 SO2 NAAQS, where the limits have been set at
levels expected to be comparably stringent to shorter-term limits. As
stated in the August 21, 2018 NPRM, EPA considered Ohio's control
strategy for the Painesville plant and found that the limits in Ohio
Administrative Code Chapter 3745-18 (OAC 3745-18) met EPA's guidelines
for acceptable emission limits based on a 30-day averaging time.
Comment: The commenter stated that a 30-day averaging time is the
same as a 720-hour averaging period rolling on a daily basis, and ``it
seems impossible to derive a 720-hour average limit that would ensure
hourly emissions of SO2 are limited to the extent necessary
to protect the 1-hour average SO2 NAAQS, unless it was shown
through air dispersion modeling that the maximum uncontrolled hourly
emissions from a source would not exceed the NAAQS.''
EPA Response: The compliance calculations for the limits applicable
to the Painesville plant units would be 720-hour averages when the unit
operates in each of those 720 hours. Hours in which the unit is not
operating are not included in the calculation, to focus the compliance
test on how well the facility's emissions are controlled during
operational hours.
EPA's April 2014 guidance provides the results of analyses which
demonstrate that limits based on periods of as long as 30 days (720
hours) can, in many cases, be reasonably considered to provide for
attainment of the 2010 SO2 NAAQS. When a 30-day emission
limit is set sufficiently lower than the 1-hour emission limit which
the modeling analysis indicated would conservatively provide for
attainment, the numerically lower 30-day limit would also be expected
to provide for attainment. In accordance with EPA guidance, Ohio
conducted modeling to determine the CEV, i.e., the emission rate that,
if emitted continuously, would result in attainment. Ohio then
established 30-day average limits that are comparably stringent to the
1-hour limits it otherwise would have established. EPA agrees with Ohio
that these limits can be expected to provide comparable air quality as
the corresponding 1-hour limits would, and EPA considers the 30-day
average limits to satisfy the requirement to provide for attainment.
EPA does not agree with the commenter that the application of a
longer term average limit requires determining the unit's maximum
uncontrolled emission rate or a maximum 1-hour emission rate that might
occur in compliance with a longer term average emission limit, or that
modeling must be conducted to show that such emission rates do not
cause NAAQS violations. The analysis that the commenter proposes would
not take proper account of the impact of variable emissions within the
longer-term limit. In particular, while such an analysis would assess
potential additional exceedances of the NAAQS level on occasions with
elevated emissions, such an analysis would fail to reflect the improved
air quality on days with lower emissions. Since compliance with a
downward adjusted long term average limit necessarily requires any
occasions of elevated emissions to be accompanied by occasions of lower
than average emissions, the commenter's proposed analysis is inadequate
for assessing the net effects of emissions sometimes being higher but
more often being lower than the CEV.
Comment: The commenter states that Ohio's approach is inconsistent
with EPA's Guideline on Air Quality Models, which in Table 8-1
``requires modeling for short term (<= 24 hours) NAAQS be based on the
allowable emissions over the averaging time of the NAAQS. Yet, the
maximum allowable hourly emission rate is difficult to predict from a
30-day average limit for an emissions unit.''
EPA Response: EPA's 2014 guidance for SO2 SIPs directly
addresses the comment regarding Table 8-1. Page A-79 of the guidance
states:
An important caveat regarding Table 8-1 of Appendix W is that
this guidance is oriented toward short term emission limits (e.g.,
1-hour emission limits), as recommended in previous guidance.
Current guidance, providing for use of longer term emission limits,
provides that after the state determines the 1-hour limit that would
be necessary to provide for attainment, any longer-term limit should
be established at a level that is sufficiently lower to provide
comparable stringency. Thus, in cases where a state wishes to apply
a longer term average limit, the attainment analysis would be based
not on the level of the longer-term limit but rather on the level of
the corresponding 1-hour emission limit that was shown in the plan
to be of comparable stringency.
Accordingly, EPA believes that Ohio has provided an appropriate
demonstration that its 30-day average limit, set to be comparably
stringent to a 1-hour limit at the modeled CEV, will provide for
attainment.
Comment: The commenter said that EPA's April 2014 guidance allows
flexibility for sources that cannot meet the hourly rate of
SO2 emissions necessary to attain the NAAQS. The CAA
requires the implementation of all reasonably available control
measures to provide for attainment. The commenter said that it is
reasonable for a source such as the Painesville plant to guard against
spikes in sulfur content of fuel and/or SO2 emissions
through proper operation of scrubbers, limiting high sulfur coal, and
testing for coal sulfur content. The commenter believes that the
flexibility in EPA's guidance has allowed Ohio to propose 30-day
average limits for the Painesville plant which fail Congress' direction
that EPA shall provide for attainment of the NAAQS.
EPA Response: EPA believes it is important to recognize that some
sources may have variable emissions, for example due to variations in
fuel sulfur content and operating rate, that can make it extremely
difficult, even with a well-designed control strategy, to ensure in
practice that stringent hourly limits are never exceeded. The
Painesville plant is complying with the Federal Boiler MACT rule by
taking enforceable limits on its operations to meet the definition of a
Limited Use boiler, operating at 10% of its annual heat input capacity.
As such, the plant will only operate intermittently, during periods of
high demand or service interruptions. This type of operation reflects a
decrease in overall emissions from this source.
The boiler MACT rule does not require that Limited Use boilers
install additional control technology, because add-on SO2
control systems require steady-state operations for good control
efficiency and cannot reduce SO2 emissions effectively for
intermittent short-term operations. The Painesville plant's revised
rules do require a reduction in allowable coal sulfur content, with
coal sampling to confirm sulfur content. Ohio EPA has determined that
the Painesville plant is unable to use very low sulfur (Powder River
Basin) coal because of the high cost of updating its facilities to
handle and use it for its limited operations; because the unique
characteristics of the coal has a detrimental effect on the
[[Page 3990]]
facility's particulate matter controls; and because of the increased
risk of fire during storage of the more volatile low-sulfur coal, which
has occurred elsewhere in Ohio with similar coal storage and handling
equipment.
EPA believes that the flexibility of the 30-day average limit is
reasonable for an intermittently-operating facility such as the
Painesville plant. As stated previously, EPA's analyses demonstrated
that its requirement for a tighter limit to be used with a longer-term
averaging period is likely to yield better air quality than is required
with a comparably stringent 1-hour limit. EPA's April 2014 guidance
states, ``if periods of hourly emissions above the critical emission
value are a rare occurrence at a source, these periods would be
unlikely to have a significant impact on air quality, insofar as they
would be very unlikely to occur repeatedly at the times when the
meteorology is conducive for high ambient concentrations of
SO2.'' The Painesville plant's limit, supplemented by an
additional 24-hour boiler heat input cap and the stringent federally
enforceable limitation on the plant's annual boiler usage, is expected
to provide for attainment of the NAAQS in accordance with the CAA's
requirements.
III. What action is EPA taking?
EPA is approving Ohio's April 3, 2015 plan, as supplemented on
October 13, 2015 and on March 13, 2017, for attaining the 2010 1-hour
SO2 NAAQS and for meeting other nonattainment area planning
requirements for the Lake County SO2 nonattainment area. EPA
is amending the codification in 40 CFR 52.1870(e) to include the
approval of Ohio's SO2 attainment plan for Lake County.
In development of this plan, Ohio amended its rules at OAC 3745-18-
49 (F) (establishing new limits for the Painesville plant), OAC 3745-
18-03 (B)(9), OAC 3745-18-03 (C)(11), and OAC 3745-18-04(D)(10)
(establishing a compliance date and other administrative provisions),
and rescinding OAC 3745-18-49(G) (reflecting the enforceable shutdown
of the Eastlake plant). These revisions became effective on February
16, 2017. EPA approved these revisions into the SIP, as codified at 40
CFR 52.1870(c), on October 11, 2018 (83 FR 51361), as part of action on
a broader range of OAC Chapter 3745-18 revisions. Thus, no additional
action is necessary to incorporate the pertinent limits into the SIP,
and this action is limited to concluding that Ohio has demonstrated
that these previously approved limits provide for attainment of the
SO2 NAAQS in Lake County and that Ohio has met the other
planning requirements for this area.
IV. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely approves state law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by state
law. For that reason, this action:
Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Orders 12866 (58
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
Is not an Executive Order 13771 (82 FR 9339, February 2,
2017) regulatory action because SIP approvals are exempted under
Executive Order 12866;
Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
Does not provide EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian tribe has
demonstrated that a tribe has jurisdiction. In those areas of Indian
country, the rule does not have tribal implications and will not impose
substantial direct costs on tribal governments or preempt tribal law as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this action and
other required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A major rule cannot
take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
804(2).
Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by April 15, 2019. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this action for the purposes of judicial review nor
does it extend the time within which a petition for judicial review may
be filed, and shall not postpone the effectiveness of such rule or
action. This action may not be challenged later in proceedings to
enforce its requirements. (See section 307(b)(2).)
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Reporting and recordkeeping
requirements, Sulfur oxides.
Dated: January 29, 2019.
Cathy Stepp,
Regional Administrator, Region 5.
[[Page 3991]]
40 CFR part 52 is amended as follows:
PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS
0
1. The authority citation for part 52 continues to read as follows:
Authority: 42 U.S.C. 7401 et seq.
0
2. In Sec. 52.1870, the table in paragraph (e) is amended by adding an
entry for ``SO2 (2010)'' after the entry for
``PM2.5 (2012)'' under the heading ``Summary of Criteria
Pollutant Attainment Plans'' to read as follows:
Sec. 52.1870 Identification of plan.
* * * * *
(e) * * *
EPA-Approved Ohio Nonregulatory and Quasi-Regulatory Provisions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Applicable geographical or non-
Title attainment area State date EPA approval Comments
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Summary of Criteria Pollutant Attainment Plans
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
SO2 (2010)...................... Lake County.................... 2/16/2017 2/14/2019, [insert Federal Register EPA is approving the
citation]. following plan elements: The
emission inventory; the
demonstration of attainment;
and revised emission limits
as meeting RACM
requirements.
* * * * * * *
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[FR Doc. 2019-02210 Filed 2-13-19; 8:45 am]
BILLING CODE 6560-50-P