[Federal Register Volume 84, Number 137 (Wednesday, July 17, 2019)]
[Proposed Rules]
[Pages 34090-34102]
[FR Doc No: 2019-15111]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2019-0340; FRL-9996-64-Region 8]

Designation of Areas for Air Quality Planning Purposes; Montana;
Redesignation Request and Associated Maintenance Plan for East Helena
SO2 Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On October 26, 2018, the Montana Department of Environmental
Quality (MDEQ) submitted a request to the EPA for redesignation of the
East Helena, Montana 1971 sulfur dioxide (SO2) National
Ambient Air Quality Standards (NAAQS) nonattainment area (NAA) to
attainment, and to approve a State Implementation Plan (SIP) revision
for a maintenance plan of the East Helena area. After review and
analysis of Montana's submittal, the EPA is proposing to redesignate
the East Helena, Montana SO2 nonattainment area to
attainment for the 1971 primary 24-hour and annual, and secondary 3-
hour SO2 NAAQS, and to approve

Montana's SIP revision for continued maintenance and attainment of the
1971 primary 24-hour and annual, and secondary 3-hour SO2
NAAQS in East Helena, Montana.

DATES: Written comments must be received on or before August 16, 2019.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2019-0340, to the Federal Rulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
www.regulations.gov. The EPA may publish any comment received to its
public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.
    Docket: All documents in the docket are listed in the
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in www.regulations.gov or in hard copy at the Air and Radiation
Division, Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop
Street, Denver, Colorado 80202-1129. The EPA requests that if at all
possible, you contact the individual listed in the FOR FURTHER
INFORMATION CONTACT section to view the hard copy of the docket. You
may view the hard copy of the docket Monday through Friday, 8:00 a.m.
to 4:00 p.m., excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Adam Clark,<PHONE_NUMBER>,
<EMAIL_ADDRESS>or Clayton Bean,<PHONE_NUMBER>,
<EMAIL_ADDRESS>Air and Radiation Division, U.S. EPA, Region 8,
Mail-code 8ARD-QP, 1595 Wynkoop Street, Denver, Colorado 80202-1129.

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.

I. Background for the EPA's Proposed Actions

A. The 1971 SO2 NAAQS

    In 1971, the EPA promulgated new primary and secondary NAAQS for
SO2.\1\ The primary standard addressed 24-hour and annual
average ambient SO2 concentrations. The secondary standard
addressed 3-hour and annual average ambient SO2
concentrations. In 1973, the EPA revoked the secondary annual average
standard.\2\ Thus, the 1971 SO2 NAAQS is comprised of a
primary 24-hour standard of 0.14 parts per million (ppm) not to be
exceeded more than once per year, a primary annual average standard of
0.03 ppm, and a secondary 3-hour standard of 0.5 ppm not to be exceeded
more than once per year.\3\
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    \1\ 36 FR 8186, April 30, 1971.
    \2\ 38 FR 25678, September 14, 1973.
    \3\ Table of historical SO2 NAAQS. See https://www3.epa.gov/ttn/naaqs/standards/so2/s_so2_history.html.
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    On June 2, 2010, the EPA revised the primary SO2 NAAQS,
thus establishing a new 1-hour SO2 standard of 75 parts per
billion (ppb). Although the 1971 primary SO2 NAAQS have been
revised to the 2010 1-hour SO2 NAAQS, today's proposed
action only addresses the 1971 SO2 NAAQS for the East Helena
NAA. The EPA notes that all of Lewis and Clark County, Montana,
including the East Helena SO2 NAA, is designated as
``attainment/unclassifiable'' under the 2010 SO2 NAAQS.\4\
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    \4\ See 40 CFR 81.327. See also the EPA's ``Air Quality
Designations for the 2010 Sulfur Dioxide (SO2) Primary
National Ambient Air Quality Standard--Round 3,'' 83 FR 1098,
January 9, 2018.
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B. Nonattainment Designation and Development of the East Helena SO2
Attainment SIP

    The American Smelting and Refining Company (ASARCO) lead smelter
began operating in 1888 in the city of East Helena, Montana. ASARCO has
been the cause of SO2 violations throughout the history of
the East Helena area,\5\ as will be described further below, and was
permanently shut down in 2001.]
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    \5\ 60 FR 5313, January 27, 1995.
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    On September 19, 1975 the EPA approved a revision to the Montana
SIP for SO2 control strategies providing for attainment and
maintenance of the 1971 SO2 NAAQS near the ASARCO lead
smelter in East Helena. SIP-approved emission limitations for
SO2 at the ASARCO smelter were limited to 80 tons per day
(tpd) and 20 tons per six hours.\6\
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    \6\ 40 FR 43216, September 19, 1975.
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    Section 107(d) of the 1977 CAA Amendments gave the EPA authority to
designate areas as nonattainment without a state's request.\7\ On March
3, 1978 the EPA designated the ``East Helena Area'' \8\ as
nonattainment for the primary and secondary SO2 NAAQS.\9\
The East Helena SO2 NAA is demarcated by a circle centered
on the previously existing ASARCO sinter storage building \10\ with a
radius of 0.67 km (0.43 miles).
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    \7\ After the EPA's initial designation of areas as attainment/
unclassifiable or nonattainment in 1978, however, subsequent
designations could be made only at a State's request. In that same
year, the EPA published, for the first time, a list of all section
107(d) nonattainment areas in 40 CFR part 81, which included East
Helena.
    \8\ Generally, where the EPA promulgated a designation for
SO2 the minimum area was to be the county in which the
violating monitoring site was located. If states had monitoring data
to substantiate the size of areas they designated, they would be
acceptable by the EPA regardless of size. See 43 FR 8962, March 3,
1978.
    \9\ 43 FR 8962, March 3, 1978.
    \10\ NAD27 UTM Zone 12, 429484 mE, 5158997 mN.
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    On November 20, 1980 the EPA conditionally approved a SIP revision
for the East Helena SO2 NAA. This SIP revision identified
the continued SO2 violations as being caused by low-level
downwash emissions from the three 110-foot stacks serving the smelter's
blast furnace operations. The control strategy identified in the SIP
revision included replacing the three 110-foot stacks with a single
425-foot stack and setting new emission limits on the 425-foot
stack.\11\ The EPA's action was conditioned upon adequate demonstration
of good engineering practice (GEP) stack height for the new blast
furnace stack, and revised dispersion modeling if GEP height was
determined to be below 375 feet. ASARCO completed a field tracer study
demonstration in 1982, and subsequently proceeded to complete
construction of its new stack based on the study results justifying a
stack height of 375 feet as necessary to overcome the effects of
downwash, which had been identified as the cause of monitored ambient
SO2 violations near the smelter site.\12\ On July 5, 1983
the EPA proposed to approve \13\ the SIP and GEP demonstration as
satisfying the conditional approval requirements, yet pending
litigation \14\ over federal stack

height regulations postponed final EPA action until years later.
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    \11\ 45 FR 76685, November 20, 1980.
    \12\ 60 FR 5313, January 27, 1995.
    \13\ 48 FR 30696 July, 5, 1983.
    \14\ Sierra Club v. Environmental Protection Agency, 719 F.2d
436 (D.C. Cir. 1983).
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    The CAA Amendments of 1990 reaffirmed the nonattainment designation
of East Helena with respect to the primary and secondary SO2
NAAQS under section 107(d).\15\ Pursuant to the CAA Amendments of 1990,
any state that lacked a fully-approved SIP complying with the
requirements of the Act for an area designated as nonattainment with
respect to the primary SO2 NAAQS, was to resubmit a SIP
fully meeting the requirements of the CAA by May 15, 1992. For the
secondary SO2 NAAQS SIP for East Helena, the EPA established
November 15, 1993 as the submittal due date.\16\
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    \15\ See 56 FR 56694, November 6, 1991, ``Designation of Areas
for Air Quality Planning Purposes'' at 56706.
    \16\ The Act did not explicitly specify a deadline for the
secondary SO2 NAAQS, however, section 172(b) provides
that the Administrator shall establish a schedule for plan
submissions, but that such submissions shall not extend longer than
three years from the date of nonattainment designation.
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    Given that the East Helena primary SO2 SIP was not
submitted by May 15, 1992, the EPA made a finding of failure to submit,
pursuant to section 179 of the Act, and notified the Governor in a
findings letter dated June 16, 1992.\17\ The date of the findings
letter started the mandatory 18-month sanction clock and established a
two-year deadline by which the EPA was required to promulgate a federal
implementation plan (``FIP'').
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    \17\ 57 FR 48614, October 27, 1992.
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    In our October 7, 1993 ``Deadline for SIP Submittal'' action (58 FR
52237) the EPA recognized that for the ASARCO smelter, the primary and
secondary SO2 NAAQS do not require the same level of
controls. Modeling results indicated an additional 35 percent reduction
in emissions was needed (beyond those reductions to achieve the primary
SO2 NAAQS) in order to comply with the secondary
SO2 NAAQS.\18\ We therefore concluded that attainment of the
secondary SO2 NAAQS will require significant emission
reductions, beyond what was required for attainment of the primary
SO2 NAAQS.
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    \18\ 58 FR 52237, October 7, 1993.
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    After the East Helena primary SO2 Attainment SIP was
submitted by the State on March 30, 1994, the EPA found the submittal
complete pursuant to section 110(k)(1) of the Act and notified the
Governor accordingly in a letter dated May 12, 1994. This completeness
determination corrected the State's deficiency and, therefore,
terminated the 18-month sanctions clock for the primary SO2
SIP under section 179 of the Act.\19\
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    \19\ 60 FR 5313, January 27, 1995.
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    On January 27, 1995 the EPA fully approved the East Helena primary
SO2 Attainment SIP for the East Helena NAA. The EPA noted in
that approval action that Montana's SIP revision only addressed the 24-
hour and annual primary SO2 NAAQS, and did not address the
3-hour secondary SO2 NAAQS.\20\ The modeling conducted by
the State to demonstrate attainment of the 1971 primary NAAQS by the
applicable attainment deadline of November 15, 1995, which the EPA
approved in our January 27, 1995 final rulemaking, will be discussed
further in Section III.A. of today's proposed rulemaking action.
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    \20\ Ibid.
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    As the State of Montana failed to submit the East Helena secondary
SO2 Attainment SIP by November 15, 1993, the EPA acted
pursuant to the non-discretionary requirement of section 179 of the Act
by notifying the Governor in a findings letter dated January 19, 1994,
of the State's failure to submit the SO2 SIP secondary
standard.\21\ In the letter, the EPA also notified Montana of sanctions
available to the EPA under section 110(m) that could be imposed,
including highway funding sanctions, 2:1 emission offsets, and
promulgation of a FIP under section 179(a). The date of the findings
letter started the mandatory 18-month sanction and the two-year FIP
clocks. The sanction clock expired due to inaction by the State on July
19, 1995, and the FIP clock expired on January 19, 1996. The EPA did
not promulgate a FIP upon expiration of the FIP clock. As the sanction
clocks were never stayed or deferred, emissions offsets and highway
sanctions were imposed by operation of law and have remained in place
to date.\22\
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    \21\ This letter is available in the docket for this action.
    \22\ See https://www.fhwa.dot.gov/environment/air_quality/highway_sanctions/sanctionsclock.cfm for the status of sanction
clocks under the CAA, including East Helena's status.
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    The State of Montana indicated that they were in the process of
revising the 3-hour secondary SO2 SIP for East Helena when
ASARCO shut down operations on April 4, 2001.\23\ Initially, the ASARCO
shutdown was to be a suspension of operations for an indeterminate
amount of time. Accordingly, ASARCO did not request revocation of their
Title V operating permit, nor their Montana Air Quality Permit (MAQP
#2557-12). ASARCO's indeterminate suspension of operations later
officially became a permanent shutdown, and the State of Montana never
resumed work on the required secondary SO2 SIP. Therefore,
the 3-hour secondary SO2 SIP revision for East Helena was
never submitted to the EPA, causing the aforementioned sanctions to
remain in place. On April 4, 2007, ASARCO's Title V permit (#OP2557-04)
expired without renewal, and on January 5, 2010, MAQP #2557-12 was
formally revoked by the State of Montana.\24\
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    \23\ See ``East Helena SO2 Redesignation Request'',
October 26, 2018, at 5.
    \24\ The request to revoke MAQP (#2557-12), and MDEQ's letter in
response confirming revocation, can be found in Appendix A of
Montana's October 26, 2018 ``Request for Redesignation of East
Helena SO2 Nonattainment Area.''
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    On November 25, 2002 the EPA made a technical correction to the
East Helena SO2 SIP pursuant to our authority under
110(k)(6) of the CAA. (67 FR 70554). Specifically, we clarified that in
our January 27, 1995 approval of the East Helena primary SO2
Attainment SIP (60 FR 5313), we failed to indicate that this approval
superseded our approval of the East Helena SO2 Attainment
SIP on September 19, 1975 and terminated the East Helena SO2
Attainment SIP approved on May 1, 1984. The November 25, 2002 action
corrected these errors.
    On October 26, 2018, the State of Montana submitted to the EPA a
request for redesignation of the East Helena SO2 NAA to
attainment for the 1971 primary and secondary NAAQS (hereafter ``East
Helena SO2 Redesignation Request''), and a SIP revision
containing a maintenance plan for the East Helena attainment area
(hereafter ``East Helena SO2 Maintenance Plan'').\25\ The
details of Montana's East Helena SO2 Redesignation Request
and Maintenance Plan are discussed in greater detail below.
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    \25\ The submissions are collectively referred to as the ``East
Helena SO2 Redesignation Request and Maintenance Plan.''
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C. Additional History of the East Helena SO2 Nonattainment
Area

    Between 1969 and 1983, concerns of contamination in the East Helena
area led to investigations by the EPA and the State of Montana. High
metal levels were found in air, soil, surface water, and dust in and
around East Helena. In 1984, the EPA listed the 140-acre ASARCO smelter
site and about 2,000 additional acres of surrounding land \26\ on the
Superfund program's National Priorities List (NPL).\27\ In 1998, the

United States Department of Justice issued a Consent Decree requiring
ASARCO to resolve major environmental compliance issues under the
Resource Conservation and Recovery Act (RCRA). ASARCO began dismantling
the smelter site following the 2001 shutdown. ASARCO filed for
bankruptcy in 2005, and on June 5, 2009, the Bankruptcy Court approved
the Consent Decree and a Settlement Agreement.\28\ In part, the
settlement agreement transferred the East Helena ASARCO properties and
administration thereof to the appointed Custodial Trustee, the Montana
Environmental Trust Group (METG), who assumed responsibility of
corrective action cleanup under oversight of the EPA. The three
remaining smelter stacks were felled in a controlled demolition on
August 4, 2009.\29\ Later, in December 2009, the smelter site was
officially transferred from ASARCO to the METG.\30\
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    \26\ The East Helena Superfund site encompasses and extends
beyond the exterior boundary of the East Helena SO2 NAA.
    \27\ ``Fourth Five-Year Review Report for the East Helena
Superfund Site,'' September 2016. See https://semspub.epa.gov/work/08/1768518.pdf. This document is also available in the docket for
this action.
    \28\ Ibid.
    \29\ See https://missoulian.com/news/state-and-regional/asarco-smokestacks-in-east-helena-toppled-in-early-morning-demolition/article_a86273aa-88e1-11de-9466-001cc4c03286.html.
    \30\ ``Fourth Five-Year Review Report for the East Helena
Superfund Site,'' September 2016. See https://semspub.epa.gov/work/08/1768518.pdf. This document is also available in the docket for
this action.
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    As of mid-2019 all that remains of the former ASARCO smelter site
is a 65-acre slag pile, and 65-acres of contaminated land that has been
capped with an evapotranspiration cover. Restorative actions have
allowed open meadows, grasslands, and wetlands to flourish on the
former site; and one and a half miles of the Prickly Pear Creek has
been successfully restored.\31\ The site is privately held by METG, and
public access is restricted. In the future, deed restrictions will be
placed on the property that will prevent another facility from being
constructed on the cap.
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    \31\ See https://www.mtenvironmentaltrust.org/east-helena/photo-galleries/east-helena-site-videos/.
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II. CAA Requirements for Redesignation Requests and Maintenance Plans

A. Statutory Provisions

    The CAA provides the requirements for redesignating a nonattainment
area to attainment. Specifically, section 107(d)(3)(E) of the CAA
allows for redesignation of a nonattainment area provided that: (1) The
Administrator determines that the area has attained the applicable
NAAQS; (2) the Administrator has fully approved the applicable
implementation plan for the area under section 110(k); (3) the
Administrator determines that the improvement in air quality is due to
permanent and enforceable reductions in emissions resulting from
implementation of the applicable SIP and applicable federal air
pollutant control regulations and other permanent and enforceable
reductions; (4) the Administrator has fully approved a maintenance plan
for the area as meeting the requirements of section 175A; and (5) the
state containing such area has met all requirements applicable to the
area for purposes of redesignation under section 110 and part D of
title I of the CAA.
    CAA section 175A provides the general framework for maintenance
plans. The maintenance plan must provide for maintenance of the NAAQS
for at least 10 years after redesignation, including any additional
control measures as may be necessary to ensure such maintenance. In
addition, maintenance plans are to contain such contingency provisions
as we deem necessary to assure the prompt correction of a violation of
the NAAQS that occurs after redesignation. The contingency measures
must include, at a minimum, a requirement that the state will implement
all control measures contained in the nonattainment SIP prior to
redesignation. Beyond these provisions, however, CAA section 175A does
not define the content of a maintenance plan.

B. EPA Guidance Applicable to the East Helena SO2
Redesignation Request and Maintenance Plan

    On April 16, 1992, the EPA provided guidance on redesignation in
the General Preamble for the Implementation of title I of the CAA
Amendments of 1990 (57 FR 13498) and supplemented this guidance on
April 28, 1992 (57 FR 18070). The EPA has provided further guidance on
processing redesignation requests in several guidance documents. Our
primary guidance on maintenance plans and redesignation requests is a
September 4, 1992 memo from John Calcagni, entitled ``Procedures for
Processing Requests to Redesignate Areas to Attainment'' (hereafter
referred to as the ``Calcagni Memo''). Specific guidance on
SO2 redesignations also appears in a January 26, 1995 memo
from Sally L. Shaver, entitled ``Attainment Determination Policy for
Sulfur Dioxide Nonattainment Areas'' (hereafter referred to as the
``Shaver Memo''). The recommendations for addressing the redesignation
request requirements of CAA section 107(d)(3)(E) and the maintenance
plan requirements of 175A provided in these guidance documents will be
referenced throughout the forthcoming sections. Guidance specific to
areas lacking ambient monitoring data, and whose historic violations
were caused by a major point source that is no longer in operation, is
found in an October 18, 2000 memo from John S. Seitz entitled
``Redesignation of Sulfur Dioxide Nonattainment Areas in the Absence of
Monitored Data'' (hereafter referred to as the ``Seitz Memo''). The
Seitz Memo exempts eligible areas from the maintenance plan
requirements of continued monitoring. The Seitz Memo also describes how
attainment and continued maintenance should be demonstrated in such
areas and how sources currently shut down should be treated if they
resume operation. The EPA finds that the East Helena SO2 NAA
is an appropriate area for application of the guidance laid out in the
Seitz Memo. Therefore, as will be discussed further in the EPA's review
of the State's 175A maintenance plan (Section III.B.), the EPA is
proposing to find that the East Helena maintenance area should not
require ambient monitoring to verify continued attainment.

III. EPA's Evaluation of the East Helena SO2 Redesignation Request and
Maintenance Plan

A. EPA Review of CAA Section 107(d)(3)(E) Requirements

    The EPA's evaluation of the East Helena SO2
Redesignation Request was based on consideration of the five
redesignation criteria provided under CAA section 107(d)(3)(E). We
analyze each of these criteria individually, below. Based on this
analysis, we propose to find that the State of Montana has met the
redesignation criteria of CAA section 107(d)(3)(E).
1. Criteria (1) Determination That the East Helena Area Has Attained
the 1971 SO2 NAAQS
a. Review of Ambient Monitoring and Emissions Data
    In the East Helena SO2 Redesignation Request, the State
primarily relied on historic SO2 ambient data which
indicated attainment of the 1971 primary and secondary NAAQS for the 15
years preceding the ASARCO facility shutdown in 2001. Ambient
SO2 monitoring began in the East Helena area as early as
1968. An enhanced ambient SO2 monitoring network was
established in 1993. This was the result of extensive efforts between
ASARCO and the State of Montana (in coordination with the EPA) to
identify maximum pollutant impact areas using

tracing studies, monitored atmospheric dispersion parameters,
dispersion modeling, and ambient SO2 concentrations.\32\ The
ambient SO2 monitoring network for the East Helena area was
discontinued on May 31, 2001 following the ASARCO shutdown.
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    \32\ ``Primary SO2 NAAQS SIP Revision for East
Helena, Montana, Technical Support Document, October 4, 1994,'' at
pages 13-15.
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    After reviewing the East Helena SO2 Redesignation
Request and the historic ambient SO2 monitoring data, the
EPA concludes that the monitoring data were collected, and quality
assured in accordance with EPA guidelines.\33\ Table 1 below shows for
all of the 1971 SO2 NAAQS the highest monitored
SO2 value in the East Helena area annually from 1987 to 2001
throughout the enhanced monitoring network.\34\
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    \33\ Calcagni Memo at 2.
    \34\ From 1986 to 1992 six SO2 monitoring sites
operated. One site was removed June 1992. In 1993, the enhanced
monitoring network added eight additional SO2 sites. In
1997, eight SO2 sites were removed from the network,
thereby leaving five (Microwave, McClellan Creek Road #4, McClellan
Creek Road #6, Water Tank, Kennedy Park) SO2 monitoring
sites in the East Helena area. These five remaining sites, together
making up the ``enhanced monitoring network,'' were located in areas
of historic violations and modeled maximum pollutant impact areas.

                                                     Table 1--Ambient SO2 Monitoring in East Helena
                                                                       [1987-2001]
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                     Max 3-hour                                Max 24-hour                               Max annual
                     value  (500                              block average                             average  (30
       Year        PPM  secondary           Monitor             (140 PPB              Monitor            PPB annual                 Monitor
                       NAAQS)                                primary NAAQS)                            primary NAAQS)
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1987.............             380  Water Tank..............           114.6  Water Tank..............           14.88  Microwave.
1988.............           446.6  Water Tank..............           107.1  Water Tank..............            9.35  Water Tank.
1989.............           396.6  Water Tank..............             120  Water Tank..............            6.28  Water Tank.
1990.............           443.4  Water Tank..............            67.1  Water Tank..............            6.95  Water Tank.
1991.............           406.6  Water Tank..............            57.5  Water Tank..............            5.01  Kennedy Park.
1992.............           * 279  Kennedy Park............            *123  Kennedy Park............         * 12.93  Kennedy Park.
1993.............         * 201.6  Water Tank..............          * 54.3  Water Tank..............          * 5.35  Kennedy Park.
1994.............           230.6  Water Tank..............            78.2  McClellan Rd #6.........           10.41  Kennedy Park.
1995.............             356  Microwave...............           112.7  McClellan Rd #6.........           10.76  Microwave.
1996.............           223.3  McClellan Rd #6.........              56  McClellan Rd #6.........            9.24  McClellan Rd #4.
1997.............             166  McClellan Rd #6.........            62.7  McClellan Rd #6.........            5.64  Water Tank.
1998.............             199  Water Tank..............            42.7  Water Tank..............            5.33  Kennedy Park.
1999.............             151  Water Tank..............            46.6  McClellan Rd #6.........            5.23  Kennedy Park.
2000.............           188.3  McClellan Rd #6.........              62  McClellan Rd #6.........            8.61  Kennedy Park.
2001.............         * 196.6  McClellan Rd #6.........          * 91.2  McClellan Rd #6.........          * 5.71  McClellan Rd #6.
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* Indicates site did not have at least 75% data completeness for all 4 quarters this year.\35\

    As Table 1 shows, there were no monitored violations of any of the
1971 SO2 NAAQS from 1987 until the ASARCO shutdown in 2001
at which time monitoring was discontinued. For the purposes of
determining whether an area has attained the SO2 NAAQS
predicated upon monitoring data, the EPA requires no fewer than two
consecutive years of clean data (i.e., eight quarters with no observed
violations) as recorded in EPA's Air Quality System (AQS).\36\ In
addition, to qualify for attainment determination purposes, the annual
average and second-highest 24-hour average concentrations must be based
upon hourly data that are at least 75 percent complete in each calendar
quarter.\37\
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    \35\ The data collected in 2001 did not meet data completeness
owing to the ASARCO facility shutdown in April 2001, after which the
monitoring network was discontinued in June 2001.
    \36\ See EPA Memo ``Section 107 Questions and Answers,'' G.T.
Helms, December 23, 1983, in the docket for this action.
    \37\ 40 CFR 50.4.
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    The East Helena NAA has recorded more than eight consecutive
quarters of quality-assured monitoring data that is free of NAAQS
violations while ASARCO operated. Specifically, the three enhanced
network monitors (Microwave, Water Tank, Kennedy Park) operating in the
period between 1987 and 1992 each showed five consecutive years (or 20
consecutive quarters) of complete, quality-assured attaining monitoring
data from 1987 to 1991. As shown, the East Helena enhanced
SO2 monitoring network experienced data completeness issues
in 1992 and 1993. Complete data are available for every year from 1994
to 2000 for all five enhanced network monitors (the aforementioned and
the McClellan Road #4 and McClellan Road #6 monitors, both added as
part of the enhanced network in 1993), which show seven consecutive
years (or 28 consecutive quarters) of complete, quality-assured
attaining monitoring data from 1994-2000. Further, from 1996 until 2001
(between the period of time from EPA's approval of the 1995 East Helena
primary SO2 Attainment SIP until ASARCO's shutdown), none of
the East Helena area ambient SO2 monitors recorded a maximum
value equivalent to or above 50% of a primary or secondary 1971
SO2 NAAQS. This decrease in monitored emissions is in
alignment with emissions data, as the average annual SO2
emissions from ASARCO dropped from 14,792 tons per year (tpy) from
1990-1995, to 10,000 tpy from 1996-2000.\38\ These data indicate that
the East Helena area was attaining the NAAQS before the ASARCO closure.
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    \38\ See East Helena SO2 Redesignation Request and
Maintenance Plan, at 8.
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    In the East Helena SO2 Redesignation Request, the State
also measured these monitor data alongside the emissions from the two
SO2 emitting sources in or near the East Helena NAA.\39\ The
State asserted that these emissions data, presented in Table 2, below,
indicate that the attaining SO2 monitor values were driven
almost entirely by SO2 emissions from ASARCO, and that it is
therefore reasonable to conclude that the monitored concentrations
would have decreased substantially (and thus continued attaining the
NAAQS) following the ASARCO shutdown.
---------------------------------------------------------------------------

    \39\ The EPA is not including emissions from the American Chemet
facility, which is located within the East Helena SO2
NAA, because this facility has not emitted a ton of SO2
in any single year since 1990.

                Table 2--Emissions Data for SO2 Sources \40\ in and Near the East Helena SO2 NAA
----------------------------------------------------------------------------------------------------------------
                                                                                Percentage of
                                                                      ASARCO         Ash Grove         total
                              Year                                   emissions       emissions    emissions from
                                                                                ASARCO
----------------------------------------------------------------------------------------------------------------
1996............................................................       10,181.97          102.88            99.0
1997............................................................       10,246.02           96.78            99.1
1998............................................................        9,797.69            95.7            99.0
1999............................................................        9,819.84          240.89            97.6
2000............................................................        9,957.31          229.23            97.7
----------------------------------------------------------------------------------------------------------------

    As shown in Table 2, the Ash Grove Cement plant (``Ash Grove'')
contributed less than 2.5% of total emissions in or near the East
Helena NAA area in each of the final five years of complete ambient
SO2 monitoring. Ash Grove is located outside the geographic
boundary of the East Helena SO2 NAA, at a distance of 3 km
to the south of the NAA's southern boundary and remains in operation.
Ash Grove's allowable SO2 emissions are limited to 386 tpy
by its MAQP #2005-13 and Title V operating permit #OP2005-09.\41\ Based
on the emissions data provided above, and consistent with our past
conclusions regarding the East Helena NAA,\42\ the EPA proposes to
concur with MDEQ's assertion that ASARCO emitted nearly all of the
SO2 in the East Helena area prior to its 2001 shutdown, and
to concur with the State that monitored SO2 concentrations
in the area would have decreased substantially following the ASARCO
shutdown.
---------------------------------------------------------------------------

    \40\ Ibid.
    \41\ These permits are available in the docket for this proposed
rulemaking action.
    \42\ As noted in the EPA's ``Establishment of Due Date for
Sulfur Dioxide SIP for the Secondary NAAQS for East Helena, MT,''
ASARCO ``is the only major source of SO2 emissions in the
East Helena area.'' See 58 FR 52237, October 7, 1993.
---------------------------------------------------------------------------

    As Montana submitted the East Helena SO2 Redesignation
Request to the EPA on October 26, 2018, contemporaneous ambient
SO2 monitoring data was not available due to the
discontinuation of the East Helena monitoring network on May 31, 2001.
Generally, for a redesignation, the most recent eight quarters of
ambient monitoring data must show compliance with the NAAQS.\43\ For
this reason and based on the recommendations of applicable guidance
discussed further below, the EPA also found it appropriate to review
available air quality modeling to complete our determination of
attainment analysis.
---------------------------------------------------------------------------

    \43\ EPA Memo ``Section 107 Designation Policy Summary,''
Sheldon Meyers, April 21, 1983.
---------------------------------------------------------------------------

b. Review of Air Quality Modeling Data
    Generally, for redesignating a nonattainment area to attainment,
the CAA requires the EPA to determine that the area has attained the
applicable NAAQS.\44\ For some pollutants, this determination relies
solely on air quality monitoring data. However, for SO2,
monitoring data alone is generally insufficient to assess an area's
attainment status. The EPA's Calcagni Memo states that for
SO2 and specified other pollutants, ``dispersion modeling
will generally be necessary to evaluate comprehensively sources'
impacts.'' Typically, attainment planning for SO2 involves
dispersion modeling used to demonstrate that the emission limits
adopted by the state suffice to assure attainment. With such modeling
available, the EPA can generally determine an area to be attaining the
standard without further modeling, provided monitoring data also
support that determination. As noted, dispersion modeling was provided
by the State and ASARCO and approved by the EPA to show attainment of
the primary, but not secondary, SO2 NAAQS. Because the EPA
has approved Montana's primary SO2 NAAQS dispersion modeling
and attainment demonstration but has not received a secondary
SO2 NAAQS dispersion modeling and attainment demonstration
from the State, we cannot rely on dispersion modeling as the sole basis
for redesignation. Therefore, we have combined our analysis of
monitoring and emissions data, listed above, with the modeling data
discussed here to reach our proposed conclusion that the East Helena
SO2 NAA currently attains the 1971 SO2 primary
and secondary NAAQS.
---------------------------------------------------------------------------

    \44\ CAA section 107(d)(3)(E)(i).
---------------------------------------------------------------------------

    In 1992, after promulgation of the CAA Amendments of 1990, MDEQ,
ASARCO, and the EPA had been working together through compliance
schedules and work plans to address issues found with early modeling
studies to predict the ambient impacts of SO2 emissions from
the ASARCO smelter. These model results indicated that the NAAQS were
violated when the facility operated at allowable emissions limits.
Modeling results predicted SO2 exceedances in two areas to
the south and southeast of the smelter. The EPA concluded from these
early modeling runs that there is an ambient SO2 problem
caused by ASARCO's emissions.\45\ Consequently, ASARCO opted to
establish an enhanced ambient monitoring network in the areas where
initial modeling results indicated maximum SO2
concentrations.
---------------------------------------------------------------------------

    \45\ ``Primary SO2 NAAQS SIP Revision for East
Helena, Montana, Technical Support Document, October 4, 1994.'' See
Appendix E, October 9, 1992 letter from Douglas Skie to Jeffery
Chaffee, with enclosure, discussing ASARCO's acceptance of the de
minimis GEP height of 65 m for the blast furnace stack.
---------------------------------------------------------------------------

    Based on the results of the early dispersion modeling, ASARCO
developed an updated modeling protocol and refined dispersion modeling
studies to demonstrate compliance with the primary SO2
NAAQS. Control strategies to meet the NAAQS in this scenario included
production and process limitations that would be put into place with
the, as of that time, yet to be submitted East Helena primary
SO2 Attainment SIP approved by the EPA on January 27, 1995
(60 FR 5313).
    The General Preamble of the Act details the EPA's interpretation of
reasonably available control measures (RACM), including reasonably
available control technology (RACT), requirements, and defines RACT for
SO2 as the control technology necessary to achieve the
NAAQS.\46\ As part of the EPA-approved ISCST and RTDM dispersion models
used to predict ambient SO2 concentrations around the ASARCO
smelter, multiple modeling runs were performed to test SO2
concentrations related to emissions from each stack. The results were
then used to develop the emission limits and operating stipulations
below for several of the major emission points of the ASARCO smelter.
---------------------------------------------------------------------------

    \46\ 57 FR 13547, April 16, 1992; at 13560-13561.
---------------------------------------------------------------------------

    From the modeling results, ASARCO developed a set of parameters for
combined emissions of the two largest SO2 emission points,
the sinter and blast furnace stacks, in order to provide operating
flexibility while still providing for attainment of both the annual and
24-hour primary SO2

NAAQS. These emissions compliance parameters were approved as a set of
three linear equations \47\ regulating the sinter stack and blast
furnace stack daily SO2 emissions. Per these parameters, the
emissions rate from the sinter stack would limit the allowable
emissions rate at the blast furnace to a level that provided for
protection of the annual and 24-hour primary SO2 NAAQS. If
the sinter stack daily emissions fell within one of the three equation
ranges, then the daily emissions of the blast furnace stack must not
exceed a corresponding given value determined by that equation.
---------------------------------------------------------------------------

    \47\ ``Primary SO2 NAAQS SIP Revision for East
Helena, Montana, Technical Support Document, October 4, 1994,'' at
20.
---------------------------------------------------------------------------

    In addition to the compliance parameters developed for regulating
combined emissions of the sinter and blast furnace stacks, maximum
daily SO2 emission limits were also established for these
and other ASARCO emission points. The maximum allowable SO2
emissions for the sinter and blast furnace stacks were set at 60.27
tons per calendar day and 29.64 tons per calendar day, respectively.
Daily emissions of SO2 from the double-contact sulfuric acid
plant stack were not to exceed 4.30 tons per calendar day. ASARCO was
required to operate continuous emission monitoring systems (CEMS) to
determine compliance with the emission limitations for the sinter plant
stack, blast furnace stack, and acid plant stack. SO2
emissions from the concentrate storage and handling building stack
(including the exhaust from the sinter plant ventilation system
baghouse) were not to exceed 46 pounds per hour or 0.552 tons per
calendar day.
    The SIP-approved daily maximum emission limits, and also the
compliance parameters for the combined emissions of the sinter and
blast furnace stacks, went into effect September 1, 1994.\48\ Two
additional emission limitations on minor stack sources at the ASARCO
smelter took effect on June 30, 1995; SO2 emissions from the
crushing mill baghouse stacks #1 and #2 were not to exceed 0.19 and
0.37 tons per calendar day, respectively.
---------------------------------------------------------------------------

    \48\ 60 FR 5313, January 27, 1995.
---------------------------------------------------------------------------

    As well as the aforementioned emission limitations, the EPA also
imposed additional provisions \49\ on ASARCO's operating stipulations
to ensure that SO2 emissions from miscellaneous volume and
fugitive sources would not increase beyond their current levels.
Moreover, ASARCO's previously approved catalyst screening maintenance
procedures were prohibited.\50\ As a result, sulfur dioxide emissions
were no longer allowed to bypass the double-contact sulfuric acid plant
for catalyst screening while the blast furnace was operating. The East
Helena primary SO2 Attainment SIP set the sunset date of the
catalyst screening exemption as November 15, 1995. The above emissions
limitations and stipulations imposed on ASARCO were incorporated into
the control strategy that the EPA fully approved for the East Helena
primary SO2 Attainment Plan's RACM (including RACT) as
attaining the primary SO2 NAAQS by November 15, 1995.
---------------------------------------------------------------------------

    \49\ ``Primary SO2 NAAQS SIP Revision for East
Helena, Montana, Technical Support Document, October 4, 1994,'' at
21.
    \50\ During catalyst screening maintenance, SO2 that
would normally be transformed into sulfuric acid and recovered as a
product, instead was bypassing the acid plant pollution controls and
was directly emitted to the atmosphere. See 49 FR 18482, May 1,
1984.
---------------------------------------------------------------------------

    In addition to these modeled emission rates for the ASARCO smelter,
Ash Grove was also included in the modeling for Montana's East Helena
SO2 Attainment SIP. The facility was modeled at a constant
rate of 28.71 grams/second, equivalent to 998 tpy of SO2. As
noted, Ash Grove's current allowable SO2 emissions are
limited to 386 tpy by MAQP #2005-13 and Title V operating permit
#OP2005-09.\51\
---------------------------------------------------------------------------

    \51\ These permits are available in the docket for this proposed
rulemaking action.
---------------------------------------------------------------------------

    The EPA's criteria for evaluation of the modeling and attainment
demonstration was the most recent version (at that time) of the EPA's
Guideline on Air Quality Models at 40 CFR part 51, Appendix W. Through
the modeling provided, Montana demonstrated that the emission limits
ensured compliance with both the 24-hour and annual primary NAAQS. The
EPA determined that the modeling indicated that both primary
SO2 NAAQS would be attained by November 15, 1995, thereby
complying with the attainment date stipulated in the CAA Amendments of
1990. The ASARCO modeling and the East Helena primary SO2
Attainment SIP were approved by the EPA on January 27, 1995 (60 FR
5313).\52\
---------------------------------------------------------------------------

    \52\ ``Primary SO2 NAAQS SIP Revision for East
Helena, Montana, Technical Support Document, October 4, 1994.'' See
C. Dispersion Modeling and Attainment Demonstration, at 16.
---------------------------------------------------------------------------

    As noted in our January 27, 1995 approval of the East Helena
primary SO2 Attainment SIP (and elsewhere in this notice),
the State of Montana was to provide the EPA with its 3-hour secondary
NAAQS Attainment SIP in a forthcoming submittal. This was due to issues
with compliance with the NAAQS, as discussed further below. After the
promulgation of the CAA Amendments of 1990, the State of Montana was to
provide modeling as part of an attainment demonstration showing
compliance with the secondary 3-hour SO2 NAAQS. Due to early
modeled NAAQS violations, ASARCO elected to perform additional
dispersion modeling using CTDMPLUS/ISCST2 and CTSCREEN models, and
control strategy evaluations to show attainment with the secondary
SO2 NAAQS. Additionally, an enhanced meteorological
monitoring network (to include doppler SODAR) was established to
collect data for the complex CTDMPLUS dispersion model. Despite these
efforts, the required submittal (including the modeled attainment
demonstration) never materialized before the ASARCO smelter ceased
operations in 2001.
    As discussed earlier in this notice, ASARCO determined that the
allowable emission rates modeled to achieve the primary 1971
SO2 NAAQS in the East Helena primary SO2
Attainment SIP would need to reduce emissions an additional 35 percent
to achieve modeled compliance with the secondary SO2 NAAQS.
In our October 7, 1993 ``Deadline for SIP Submittal'' action, we noted
that the substantial emissions reductions required to model attainment
of the secondary SO2 NAAQS cannot reasonably be achieved
through production or process changes. ASARCO estimated that if
production were reduced by 35 percent, annual revenue would be reduced
by more than $12.4 million. ASARCO contended that such a reduction in
revenue would make continued operation of the East Helena smelter
economically infeasible. Though the EPA could not confirm the projected
level of revenue loss, we noted that the economic impact to the
industry and the community would be significant. We agreed with the
State of Montana and ASARCO that the only feasible way to meet the
secondary SO2 NAAQS, based on modeling results, would be to
install new air pollution control equipment or new process
technologies.\53\ Because Montana failed to submit the required
secondary SO2 NAAQS SIP, highway and offset sanctions were
imposed by operation of law pursuant to a finding of failure to submit
for a designated nonattainment area (42 U.S.C. 7509(a)(1)) on December
16, 1993.\54\
---------------------------------------------------------------------------

    \53\ 58 FR 52237, October 7, 1993.
    \54\ See EPA's January 19, 1994 letter to Montana Governor
Racicot in the docket for this action.
---------------------------------------------------------------------------

    Considering ASARCO's estimate (based on dispersion modeling) \55\
that

an additional 35 percent emissions reduction would be necessary to meet
the secondary SO2 NAAQS, the EPA concludes that this level
of reduction was far surpassed by the ASARCO shutdown. ASARCO's maximum
allowable SO2 emissions were permitted at 18,773 tpy when
the EPA determined that this level of control was sufficient to attain
the 1971 primary SO2 NAAQS, and thus approved the East
Helena primary SO2 Attainment SIP.\56\ As noted, Ash Grove
was also included in this attainment modeling, with a modeled constant
emission rate of 28.71 grams per second, equivalent to 998 tpy of
SO2. Hence, an additional reduction of 6,570.5 tpy (35
percent of 18,773) of SO2 from ASARCO, or estimated
allowable emissions 12,202.5 tpy, should suffice to meet the secondary
SO2 NAAQS even if Ash Grove were to emit 998 tpy of
SO2 annually, over 2.5 times current Ash Grove allowable
emissions. The current allowable emissions in the East Helena area are
386.09 tpy of SO2 (See Table 3), just 3 percent of the
estimated allowable rates sufficient to attain the secondary
SO2 NAAQS. On this basis, the EPA is proposing to conclude
that the modeling performed as part of the East Helena primary
SO2 Attainment SIP, considered alongside current allowable
emissions in the East Helena area and the attaining monitoring listed
in Table 1, demonstrate that the East Helena area is attaining the 3-
hour secondary SO2 NAAQS.
---------------------------------------------------------------------------

    \55\ 58 FR 52237, October 7, 1993.
    \56\ ASARCO's enforceable SO2 emission limits have
been comprised of permit limits and SIP-approved limits. ASARCO's
MAQP SO2 emission limit was 18,733 tpy before the permit
was revoked in 2010. The East Helena primary SO2
Attainment SIP further strengthened ASARCO's SO2
emissions limits as discussed in detail above. All of ASARCO's
emission limits, be they SIP-approved or permitted, are enforceable.
Had ASARCO operated at its daily maximum emission limits as a
constant yearlong rate, doing so would have violated the MAQP
emission limit and the enforceable compliance parameters. The daily
maximum emission limit was never intended as a constant maximum
allowable emission rate. Rather, the 1995 primary SO2
Attainment SIP emission limits and operating stipulations were
developed to provide ASARCO with maximum operating flexibility.
---------------------------------------------------------------------------

    As will be discussed further in the EPA's review of 107(d)(3)(E)
criteria 2 and 5, the EPA's longstanding interpretation of the
nonattainment planning requirements of CAA section 172 is that once an
area is attaining the NAAQS, those requirements are not ``applicable''
for purposes of CAA section 107(d)(3)(E)(ii) and therefore need not be
approved into the SIP before the EPA can redesignate the area. The EPA
is proposing to reach a similar conclusion regarding the State's
outstanding requirement to submit to the EPA a 3-hour secondary NAAQS
Attainment SIP. Specifically, because the EPA is proposing to conclude
that the East Helena NAA is currently attaining the 3-hour secondary
SO2 NAAQS, the State is not required to also submit a SIP
providing for such attainment.
c. EPA's Proposed Determination of Attainment
    As discussed above, the normal prerequisite for redesignation of a
nonattainment area is submittal of quality-assured ambient data with no
violations of the NAAQS for the most recent eight consecutive
quarters.\57\ Generally, a modeling demonstration is also necessary for
SO2 nonattainment areas seeking to redesignate.\58\ The
Seitz Memo recognizes that states should be provided an opportunity to
request redesignation for areas where there is no contemporary
monitoring data available if there is no reasonable basis for assuming
that SO2 violations persist after closure of the sources
that were the cause of these violations.\59\ We find that East Helena
is such an area, and that available monitoring and modeling data
discussed above also indicate current attainment of both the primary
and secondary 1971 SO2 NAAQS. We therefore propose to
determine that the East Helena NAA is attaining the primary and
secondary 1971 SO2 NAAQS.
---------------------------------------------------------------------------

    \57\ Helms Memo at 1.
    \58\ Calcagni Memo at 3.
    \59\ Seitz Memo at 1.
---------------------------------------------------------------------------

2. Criteria (2)--Montana Has a Fully Approved SIP Under Section 110(k);
and Criteria (5)--Montana Has Met All Applicable Requirements Under
Section 110 and Part D of Title I of the CAA
    For redesignating a nonattainment area to attainment under a NAAQS,
the CAA requires the EPA to determine that the state has met all
applicable requirements for that NAAQS under section 110 and part D of
title I of the CAA (CAA section 107(d)(3)(E)(v)) and that the state has
a fully approved SIP under section 110(k) for that NAAQS for the area
(CAA section 107(d)(3)(E)(ii)). The EPA proposes to find that Montana
has met all applicable SIP requirements for the East Helena
SO2 NAA under section 110 of the CAA (general SIP
requirements) for purposes of redesignation. Additionally, the EPA
proposes to find that the Montana SIP satisfies the criterion that it
meets applicable SIP requirements for purposes of redesignation under
part D of title I of the CAA in accordance with section
107(d)(3)(E)(v). Further, the EPA proposes to determine that the SIP is
fully approved with respect to all requirements applicable for the 1971
SO2 NAAQS for purposes of redesignation in accordance with
section 107(d)(3)(E)(ii). In making these determinations, the EPA
ascertained which requirements are applicable to the East Helena
SO2 NAA and, if applicable, that they are fully approved
under section 110(k).
a. The East Helena SO2 NAA Has Met All Applicable
Requirements Under Section 110 and Part D of the CAA
General SIP Requirements
    General SIP elements and requirements are delineated in section
110(a)(2) of title I, part A of the CAA. These requirements include,
but are not limited to, the following: Submittal of a SIP that has been
adopted by the state after reasonable public notice and hearing;
provisions for establishment and operation of appropriate procedures
needed to monitor ambient air quality; implementation of a source
permit program; provisions for the implementation of part C
requirements (Prevention of Significant Deterioration (PSD)) and
provisions for the implementation of part D requirements (New Source
Review (NSR) permit programs); provisions for air pollution modeling;
and provisions for public and local agency participation in planning
and emission control rule development.
    Section 110(a)(2)(D) requires that SIPs contain certain measures to
prevent sources in a state from significantly contributing to air
quality problems in another state. To implement this provision, the EPA
has required certain states to establish programs to address the
interstate transport of air pollutants. The section 110(a)(2)(D)
requirements for a state are not linked with a particular nonattainment
area's designation and classification in that state. The EPA believes
that the requirements linked with a particular nonattainment area's
designation and classifications are the relevant measures to evaluate
in reviewing a redesignation request. The transport SIP submittal
requirements, where applicable, continue to apply to a state regardless
of the designation of any one particular area in the state. Thus, the
EPA does not believe that the CAA's interstate transport requirements
should be construed to be applicable requirements for purposes of
redesignation.
    In addition, the EPA believes other section 110 elements that are
neither connected with nonattainment plan submissions nor linked with
an area's attainment status are applicable

requirements for purposes of redesignation. The area will still be
subject to these requirements after the area is redesignated. The
section 110 and part D requirements which are linked with a particular
area's designation and classification are the relevant measures to
evaluate in reviewing a redesignation request. This approach is
consistent with the EPA's existing policy on applicability (i.e., for
redesignations) of conformity and oxygenated fuels requirements, as
well as with section 184 ozone transport requirements. See Reading,
Pennsylvania, proposed and final rulemakings (61 FR 53174-53176,
October 10, 1996), (62 FR 24826, May 7, 2008); Cleveland-Akron-Loraine,
Ohio, final rulemaking (61 FR 20458, May 7,1996); and Tampa, Florida,
final rulemaking at (60 FR 62748, December 7, 1995). See also the
discussion on this issue in the Cincinnati, Ohio, redesignation (65 FR
37890, June 19, 2000), and in the Pittsburgh, Pennsylvania,
redesignation (66 FR 50399, October 19, 2001).
Title I, Part D, Applicable SIP Requirements
    Section 172(c) of the CAA sets forth the basic requirements of
attainment plans for nonattainment areas that are required to submit
them pursuant to section 172(b). Subpart 5 of part D, which includes
section 191 and 192 of the CAA, establishes requirements for
SO2, nitrogen dioxide and lead nonattainment areas. A
thorough discussion of the requirements contained in sections 172(c)
can be found in the General Preamble for Implementation of Title I (57
FR 13498).
Subpart 5 Section 172 Requirements
    Section 172(c)(1) requires the plans for all nonattainment areas to
provide for the implementation of all RACM as expeditiously as
practicable and to provide for attainment of the NAAQS. The EPA
interprets this requirement to impose a duty on all nonattainment areas
to consider all available control measures and to adopt and implement
such measures as are reasonably available for implementation in each
area as components of the area's attainment demonstration. Under
section 172, states with nonattainment areas must submit plans
providing for timely attainment and meeting a variety of other
requirements.
    The EPA's longstanding interpretation of the nonattainment planning
requirements of section 172 is that once an area is attaining the
NAAQS, those requirements are not ``applicable'' for purposes of CAA
section 107(d)(3)(E)(ii) and therefore need not be approved into the
SIP before the EPA can redesignate the area. In the 1992 General
Preamble for Implementation of Title I, the EPA set forth its
interpretation of applicable requirements for purposes of evaluating
redesignation requests when an area is attaining a standard. See 57 FR
13498, 13564 (April 16, 1992). The EPA noted that the requirements for
Reasonable Further Progress (RFP) and other measures designed to
provide for attainment do not apply in evaluating redesignation
requests because those nonattainment planning requirements ``have no
meaning'' for an area that has already attained the standard. Id. This
interpretation was also set forth in the Calcagni Memo. The EPA's
understanding of section 172 also forms the basis of its Clean Data
Policy, which was articulated with regard to SO2 in the 2010
SO2 NAA Guidance and suspends a state's obligation to submit
most of the attainment planning requirements that would otherwise
apply, including an attainment demonstration and planning SIPs to
provide for RFP, RACM, and contingency measures under section
172(c)(9). Courts have upheld the EPA's interpretation of section
172(c)(1) for ``reasonably available'' control measures and control
technology as meaning only those controls that advance attainment,
which precludes the need to require additional measures where an area
is already attaining. NRDC v. EPA, 571 F.3d 1245, 1252 (D.C. Cir.
2009); Sierra Club v. EPA, 294 F.3d 155, 162 (D.C. Cir. 2002); Sierra
Club v. EPA, 314 F.3d 735, 744 (5th Cir. 2002); Sierra Club v. EPA, 375
F.3d 537 (7th Cir. 2004). But see Sierra Club v. EPA, 793 F.3d 656 (6th
Cir. 2015).
    Therefore, because attainment has been reached in the East Helena
SO2 NAA, no additional measures are needed to provide for
attainment, and section 172(c)(1) requirements for an attainment
demonstration and RACM are not part of the ``applicable implementation
plan'' required to have been approved prior to redesignation per CAA
section 107(d)(3)(E)(ii). The other section 172 requirements that are
designed to help an area achieve attainment--the section 172(c)(2)
requirement that nonattainment plans contain provisions promoting
reasonable further progress, the requirement to submit the section
172(c)(9) contingency measures, and the section 172(c)(6) requirement
for the SIP to contain control measures necessary to provide for
attainment of the NAAQS--are also not required to be approved as part
of the ``applicable implementation plan'' for purposes of satisfying
CAA section 107(d)(3)(E)(ii).\60\
---------------------------------------------------------------------------

    \60\ The EPA notes that MDEQ has met the requirements of CAA
section 172(c)(1), (2), (6), and (9) for the 1971 primary
SO2 NAAQS, but not for the 1971 secondary SO2
NAAQS. 60 FR 5315, January 27, 1995.
---------------------------------------------------------------------------

    Section 172(c)(3) requires submission and approval of a
comprehensive, accurate, and current inventory of actual emissions. The
East Helena primary SO2 Attainment SIP contained an
inventory which the EPA approved as meeting the requirements of CAA
section 172(c)(3).\61\ This inventory reported annual SO2
emissions for the ASARCO facility at approximately 18,000 tpy, with
approximately 280 tpy attributed to the Ash Grove kiln stacks. The more
contemporary emissions inventory submitted as part of the maintenance
plan for the East Helena SO2 NAA will be discussed further
in the maintenance plan portion of this proposed action.
---------------------------------------------------------------------------

    \61\ 60 FR 5315, January 27, 1995.
---------------------------------------------------------------------------

    Section 172(c)(4) requires the identification and quantification of
allowable emissions for major new and modified stationary sources to be
allowed in an area, and section 172(c)(5) requires source permits for
the construction and operation of new and modified major stationary
sources anywhere in the nonattainment area. The EPA has a longstanding
interpretation that because Nonattainment NSR (NNSR) is replaced by PSD
upon redesignation, nonattainment areas seeking redesignation to
attainment need not have a fully approved part D NNSR program in order
to be redesignated. A more detailed rationale for this view is
described in a memorandum from Mary Nichols, Assistant Administrator
for Air and Radiation, dated October 14, 1994, entitled ``Part D New
Source Review Requirements for Areas Requesting Redesignation to
Attainment.'' Montana currently has a fully-approved PSD and part D
NNSR program in place at Administrative Rules of Montana (ARM)
Subchapter 8. Montana's PSD program will become effective in the East
Helena SO2 NAA upon redesignation to attainment.
    Section 172(c)(7) requires the SIP to meet the applicable
provisions of section 110(a)(2). As noted above, the EPA believes the
Montana SIP meets the requirements of section 110(a)(2) applicable for
purposes of redesignation.
Section 176 Conformity Requirements
    Section 176(c) of the CAA requires states to establish criteria and
procedures to ensure that federally supported or funded projects
conform to

the air quality planning goals in the applicable SIP. The requirement
to determine conformity applies to transportation plans, programs, and
projects that are developed, funded, or approved under title 23 of the
United States Code (U.S.C.) and the Federal Transit Act (transportation
conformity) as well as to all other federally supported or funded
projects (general conformity). State transportation conformity SIP
revisions must be consistent with federal conformity regulations
relating to consultation, enforcement, and enforceability that the EPA
promulgated pursuant to its authority under the CAA.
    Montana has an approved general conformity SIP for the East Helena
area. See 67 FR 62392 (October 7, 2002). Moreover, the EPA interprets
the conformity SIP requirements as not applying for purposes of
evaluating a redesignation request under section 107(d) because, like
other requirements listed above, state conformity rules are still
required after redesignation and federal conformity rules apply where
state rules have not been approved. See Wall v. EPA, 265 F.3d 426 (6th
Cir. 2001) (upholding this interpretation); see also 60 FR 62748
(December 7, 1995) (redesignation of Tampa, Florida).
    For these reasons, the EPA proposes to find that Montana has
satisfied all applicable requirements for purposes of redesignation of
the East Helena SO2 NAA under section 110 and part D of
title I of the CAA.
b. The East Helena SO2 NAA Has a Fully Approved Applicable
SIP Under Section 110(k) of the CAA
    The EPA has fully approved the applicable Montana SIP for the East
Helena SO2 NAA under section 110(k) of the CAA for all
requirements applicable for purposes of redesignation. As indicated
above, the EPA believes that the section 110 elements that are neither
connected with nonattainment plan submissions nor linked to an area's
nonattainment status are not applicable requirements for purposes of
redesignation. The EPA has approved all part D requirements applicable
under the 1971 SO2 NAAQS, as identified above, for purposes
of this redesignation.
3. Criteria (3)--The Air Quality Improvement in the East Helena
SO2 NAA Is Due to Permanent and Enforceable Reductions in
Emissions
    For redesignating a nonattainment area to attainment, the CAA
requires the EPA to determine that the air quality improvement in the
area is due to permanent and enforceable reductions in emissions
resulting from implementation of the SIP, applicable federal air
pollution control regulations, and other permanent and enforceable
reductions (CAA section 107(d)(3)(E)(iii)). The EPA proposes to find
that Montana has demonstrated that the observed air quality improvement
in the East Helena SO2 NAA is due to permanent and
enforceable reductions in emissions. Specifically, the EPA considers
the shutdown of the ASARCO smelter, identified as the cause of
SO2 NAAQS violations,\62\ to be both permanent and
enforceable due to the source's dismantling and permit revocation. The
EPA notes that the ASARCO smelter was still operating during the 1987-
2001 period during which the 1971 primary and secondary SO2
NAAQS was attained across the East Helena enhanced monitoring network.
Due to the ASARCO shutdown, the EPA reasonably concludes that the 1971
SO2 NAAQS would have and will continue to be attained by a
far greater margin following the facility's shutdown. As stated in the
Calcagni Memo, ``Emission reductions from source shutdowns can be
considered permanent and enforceable to the extent that those shutdowns
have been reflected in the SIP and all applicable permits have been
modified accordingly.'' \63\ As noted, MDEQ revoked ASARCO's MAQP
#2557-12 on January 5, 2010, and the source's Title V permit #OP2557-04
expired on April 4, 2007.\64\ Further, the ASARCO facility has been
demolished, making its future operation impossible and thus exhibiting
the permanence of the emissions reductions in the nonattainment area.
Any new sources seeking to operate within the East Helena NAA would
first be required to demonstrate that their new SO2
emissions would not interfere with attainment and maintenance of the
1971 (and 2010) SO2 NAAQS.\65\ Therefore, the EPA is
proposing to find that the air quality improvement in the East Helena
SO2 NAA is due to permanent and enforceable reductions in
emissions.
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    \62\ 58 FR 52237, October 7, 1993.
    \63\ Calcagni Memo at 10.
    \64\ Permit revocation letter is included in the docket for this
action.
    \65\ All 1971 SO2 NAAQS will continue to apply in the
East Helena SO2 NAA (in addition to the 2010
SO2 NAAQS) after redesignation to attainment unless
further action is taken by the State requesting 1971 primary
SO2 NAAQS revocation. As stated in the 2010
SO2 NAAQS promulgation, ``EPA is also providing that the
annual and 24-hour NAAQS remain in place for any current
nonattainment area . . . until the affected area submits, and EPA
approves, a SIP with an attainment, implementation, maintenance and
enforcement SIP which fully addresses the attainment and maintenance
requirements of the new SO2 NAAQS.'' See 75 FR 35581,
June 22, 2010.
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4. Criteria (4)--The East Helena SO2 Nonattainment Area Has
a Fully Approved Maintenance Plan Pursuant to Section 175A of the CAA
    To redesignate a nonattainment area to attainment, the CAA requires
the EPA to determine that the area has a fully approved maintenance
plan pursuant to section 175A of the CAA (CAA section
107(d)(3)(E)(iv)). In conjunction with its request to redesignate the
East Helena SO2 NAA to attainment for the 1971 primary and
secondary SO2 NAAQS, MDEQ submitted a SIP revision to
provide for the maintenance of these NAAQS for at least 10 years after
the effective date of redesignation to attainment. As will be discussed
in further detail in Section III.B., ``CAA Section 175A Requirements,''
the EPA is proposing to find that this maintenance plan for the area
meets the requirements for approval under section 175A of the CAA.

B. EPA Review of CAA Section 175A Requirements

1. Maintenance Plan Requirements
    CAA section 175A sets forth the elements of a maintenance plan for
areas seeking redesignation from nonattainment to attainment. Under
section 175A, the plan must demonstrate continued attainment of the
applicable NAAQS for at least 10 years after the Administrator approves
a redesignation to attainment. Eight years after the redesignation, the
state must submit a revised maintenance plan demonstrating that
attainment will continue to be maintained for the 10 years following
the initial 10-year period. To address the possibility of future NAAQS
violations, the maintenance plan must contain contingency measures as
the EPA deems necessary to assure prompt correction of any future
SO2 NAAQS violations. The Calcagni Memo provides further
guidance on the content of a maintenance plan, explaining that a
maintenance plan should address five requirements: The attainment
emissions inventory; maintenance demonstration; monitoring;
verification of continued attainment; and a contingency plan.\66\
---------------------------------------------------------------------------

    \66\ Calcagni Memo at 8-13.
---------------------------------------------------------------------------

    As noted, the Seitz Memo provides maintenance plan guidance
specific to nonattainment areas whose historic violations were caused
by a major point source that is no longer in operation. The Seitz memo
provides a path for such areas to justify exemption from

maintenance plan requirements of continued monitoring and describes how
attainment and continued maintenance could be demonstrated in such
areas. Based on our review of the East Helena SO2
Redesignation Request and relevant past rulemaking actions,\67\ the EPA
finds that the East Helena SO2 NAA is an appropriate area
for application of the guidance laid out in the Seitz Memo. The EPA has
therefore elected to assess the East Helena SO2 Maintenance
Plan based on the recommendations provided in the Seitz Memo, as
discussed further below.
---------------------------------------------------------------------------

    \67\ 60 FR 5315, January 27, 1995.
---------------------------------------------------------------------------

2. Review of the East Helena SO2 Maintenance Plan in the
Context of the Seitz Memo
    In order to allow areas to qualify for redesignation to attainment,
the Seitz Memo policy requires that the maintenance plan address
otherwise applicable provisions, and include: (1) Emissions inventories
representing actual emissions when violations occurred, current
emissions and emissions projected to the 10th year after redesignation;
(2) Dispersion modeling showing that no NAAQS violations will occur
over the next 10 years and that the shut down source was the dominant
cause of the high concentrations in the past; (3) Evidence that if the
shut down source resumes operation, it would be considered a new source
and be required to obtain a permit under the PSD provisions of the CAA;
and (4) A commitment to resume monitoring before any major
SO2 source commences operation. The EPA will address these
requirements individually, below.
a. Emissions Inventory
    The Seitz Memo recommends a state's maintenance plan include
emissions inventories representing actual emissions when violations
occurred, current emissions and emissions projected to the 10th year
after redesignation. Montana's East Helena SO2 Maintenance
Plan included both past actual and future projected attainment
emissions inventories \68\ for the East Helena SO2 NAA. The
two sources included in these inventories are the American Chemet
Corporation (Chemet) and Ash Grove, despite the latter facility's
location outside of the East Helena SO2 NAA. MDEQ's future
projected attainment inventory used Chemet's permitted allowable
SO2 limit of 0.09 tpy (per MAQP #1993-19) and Ash Grove's
permitted allowable limit of 386 tpy, to calculate a total projection
of 386.09 tpy of SO2 emissions each year from 2017 to 2026.
This attainment inventory is provided in Table 3, below, with actual
emissions replacing the State's projected allowable limits for 2017. We
conclude that the inventories provided by the State are complete,
accurate, and consistent with applicable CAA provisions and the Seitz
Memo.
---------------------------------------------------------------------------

    \68\ East Helena SO2 Redesignation Request and
Maintenance Plan, October 26, 2018, at 13-14.
---------------------------------------------------------------------------

    The State also included historic emissions data for ASARCO and Ash
Grove from 1990 to 2001.\69\ Neither the State nor the EPA has
emissions data available for these facilities prior to 1990, due to
ASARCO's 2001 shut down and the passage of time. Therefore, there is
not an inventory available that can provide actual emissions when
violations occurred, as recommended by the Seitz Memo. We do not
consider this to be an issue, as the historic emissions inventory
provided by the State and our review of previous rulemaking actions for
East Helena clearly show that the shut down source, ASARCO, was the
cause of historic SO2 violations.
---------------------------------------------------------------------------

    \69\ Id. at 8.

Table 3--East Helena SO2 Maintenance Area Projected Attainment Inventory
------------------------------------------------------------------------
                       Year                         Ash grove    Chemet
------------------------------------------------------------------------
2017..............................................      * 102     * 0.02
2018..............................................        386       0.09
2019..............................................        386       0.09
2020..............................................        386       0.09
2021..............................................        386       0.09
2022..............................................        386       0.09
2023..............................................        386       0.09
2024..............................................        386       0.09
2025..............................................        386       0.09
2026..............................................        386       0.09
------------------------------------------------------------------------
* Indicates actual emissions.

b. Dispersion Modeling
    Past EPA policy memoranda on SO2 redesignations have
recommended dispersion modeling. Per the Seitz Memo, the purpose of
such modeling analysis is to show that; (1) No SO2 NAAQS
violations presently occur or can be projected to occur during the next
10 years anywhere within the nonattainment area, and (2) point sources,
which have since shut down, were the dominant sources contributing to
high SO2 concentrations in the airshed.\70\ The State
elected not to submit an updated dispersion modeling analysis to the
EPA as part of the East Helena SO2 Maintenance Plan. For
this reason, the EPA is relying on the dispersion modeling conducted in
coordination with ASARCO, the MDEQ, and the EPA in the 1990's as part
of the East Helena primary SO2 Attainment Plan, to make this
two-part showing. An in depth discussion on this modeling is presented
in section III.A.1., above.
---------------------------------------------------------------------------

    \70\ Seitz Memo at 3.
---------------------------------------------------------------------------

    The EPA finds that the dispersion modeling for the East Helena
primary SO2 Attainment Plan is adequate to make the two-part
showing recommended by the Seitz Memo. First, the SO2 limits
relied upon to model attainment of the 1971 primary SO2
NAAQS, and the additional 35 percent SO2 reduction necessary
to model attainment of the secondary SO2 NAAQS, both
projected annual ASARCO emissions above 10,000 tpy and Ash Grove
emissions at 998 tpy. Because current allowable emissions in the East
Helena area are just 386.09 tpy, we find this sufficient evidence that
no violations presently occur or can be projected to occur during the
next 10 years anywhere within the nonattainment area. Second, the
information provided throughout today's proposed rulemaking, most
notably Table 2, clearly demonstrate that ASARCO was the dominant
source contributing to high SO2 concentrations in the East
Helena area. For these reasons, the EPA finds that the ambient
SO2 modeling requirement for redesignations and maintenance
plans is met.
c. Permitting of New or Modified Sources
    For the East Helena SO2 NAA, the NNSR permit program
responsibilities are held by MDEQ. MDEQ has longstanding, SIP-approved
PSD and minor NSR permitting programs.\71\ In conjunction with all SIP-
approved requirements of MDEQ's SIP-approved PSD permitting program,
the Source Impact Analysis requires ``[t]he owner or operator of the
proposed source or modification shall demonstrate that allowable
emission increases from the proposed source or modification, in
conjunction with all other applicable emission increases or reductions
(including secondary emissions), would not cause or contribute to air
pollution in violation of any national ambient air quality standard in
any air quality control region or any applicable maximum allowable
increase over the baseline concentration in any area.'' \72\
---------------------------------------------------------------------------

    \71\ ARM Title 17, Chapter 8, Subchapters 7, 8, 9 and 10.
    \72\ ARM 17.8.820.
---------------------------------------------------------------------------

    Furthermore, in conjunction with all SIP-approved requirements of
MDEQ's SIP-approved minor source permitting program, Conditions For
Issuance or

Denial of Permit,\73\ requires that, ``[a] Montana air quality permit
may not be issued for a new or modified facility or emitting unit
unless the applicant demonstrates that the facility or emitting unit
can be expected to operate in compliance with the Clean Air Act of
Montana and rules adopted under that Act, the Federal Clean Air Act and
rules promulgated under that Act (as incorporated by reference in ARM
17.8.767), and any applicable requirement contained in the Montana
State Implementation Plan (as incorporated by reference in ARM
17.8.767), and that it will not cause or contribute to a violation of
any Montana or national ambient air quality standard.'' MDEQ is
committed to continuing to implement its SIP-approved major and minor
source permitting programs in the East Helena maintenance area to
ensure that any new or modified (or reopened) \74\ industrial source of
SO2 emissions will not cause or contribute to a subsequent
SO2 NAAQS violation in the area. Further, any appropriate
changes to the ARM will be submitted to the EPA for approval as a SIP
revision.
---------------------------------------------------------------------------

    \73\ ARM 17.8.749.
    \74\ The EPA does not foresee any new source operating within
the boundaries of the East Helena NAA due to its Superfund
designation, completed remediation activities to date, and
institutional controls imposed on the East Helena Site (including
future deed restrictions).
---------------------------------------------------------------------------

    These programs will apply to any major source wishing to locate in
the East Helena NAA once the it is redesignated to attainment. The MDEQ
commitment to treat any major source in or near East Helena as ``new''
under the PSD program satisfies the preconstruction permit provision of
the Seitz Memo as one of the prerequisites to redesignation.
d. Monitoring
    In the East Helena SO2 Maintenance Plan, the State
requires installation of appropriate SO2 monitoring for a
minimum of three years if a major source of SO2 attempts to
locate within the East Helena SO2 NAA and the source's
modeling indicates that the SO2 impacts are greater than 75
percent of the NAAQS including background to ensure that the NAAQS are
adequately protected. Moreover, Montana's PSD program also requires
that permit applicants conduct preconstruction monitoring to identify
baseline concentrations. Together, these commitments address the
monitoring provision of the Seitz Memo.
3. Review of Remaining Maintenance Plan Provisions
    As discussed above, CAA section 175A sets forth the statutory
requirements for maintenance plans, and the Calcagni and Shaver memos
cited above contain specific EPA guidance. The only maintenance plan
element not covered by the Seitz Memo is the contingency provision. CAA
Section 175A provides that maintenance plans ``contain such contingency
provisions as the Administrator deems necessary to assure that the
State will promptly correct any violation of the standard which occurs
after the redesignation of the area as an attainment area.''
    The East Helena SO2 Maintenance Plan includes the
State's commitment to continue to implement and enforce measures
necessary to maintain the SO2 NAAQS. MDEQ's current
operating permit program places limits on SO2 emissions from
existing sources. Should an existing facility (such as Chemet) want to
increase SO2 emissions by 40 tpy or more, the facility would
be subject to the PSD program. Should a new facility be constructed in
the East Helena maintenance area, the facility would also be subject to
PSD.
    The Calcagni Memo emphasizes the importance of specific contingency
measures, schedules for adoption, and action levels to trigger
implementation of the contingency plan. The Calcagni Memo also states
that a contingency plan must require that the state implement all
measures contained in the part D nonattainment plan. Since all of the
measures contained in the East Helena primary SO2 Attainment
Plan (which satisfied part D for the 1971 primary NAAQS) specifically
addressed the ASARCO facility, the EPA does not find it reasonable to
contain such measures in the East Helena SO2 Maintenance
Plan now that the facility does not exist. Additionally, the EPA is
proposing to conclude that the projected allowable SO2
emissions limits for the two remaining sources in the East Helena area
(Ash Grove and Chemet) are protective of the NAAQS. For these reasons,
the State's contingency plan focuses on ensuring that new sources or
modifications of existing permitted sources are protective of the
SO2 NAAQS. We agree with the State that any new source
planning to locate within the maintenance area or existing source
proposing a significant \75\ increase in SO2 emissions would
be subject to Montana's SIP-approved PSD and minor NSR permitting
programs.\76\ Thus, we find that MDEQ's permitting program is
sufficient to track future air quality trends and to assure that the
East Helena maintenance area will not violate the NAAQS. If Montana
identifies the potential for a NAAQS violation through the permitting
process, the State would be required to ascertain what measures must be
taken to avoid the violation. We are therefore proposing to conclude
that the East Helena SO2 Maintenance Plan satisfactorily
addresses the ``contingency plan'' requirement of CAA section 175A.
---------------------------------------------------------------------------

    \75\ Per 40 CFR 52.21(b)(23)(i), a net emissions increase or
potential to emit of 40 tpy or greater is considered ``significant''
for SO2.
    \76\ ARM Title 17, Chapter 8, Subchapters 7, 8, 9 and 10.
---------------------------------------------------------------------------

    The EPA generally requires that a state continue ambient monitoring
to meet the maintenance plan requirement for verification of continued
attainment. However, the Seitz Memo provides the opportunity for
redesignated areas to be exempt from continued ambient monitoring of
maintenance areas when the dominant source of SO2 in the
area has shut down.\77\ As discussed earlier in this proposed notice,
we find that the East Helena SO2 NAA's unique circumstances
are appropriate for application of the Seitz Memo guidance. Therefore,
we determine that in this instance, an exemption to continued
monitoring would be appropriate. If today's action is finalized as
proposed, MDEQ will not be monitoring to verify SO2 NAAQS
compliance in the East Helena area unless required by Montana's
permitting program following the introduction of a new or modified
source to the area. The state has provided evidence that SO2
monitoring conducted between 1987 and ASARCO's shutdown in 2001 met the
applicable NAAQS with no violations observed during that time (See
Table 1). Additionally, due to the total removal of the ASARCO
facility, the source of the SO2 NAAQS violations have been
eliminated. With ASARCO removed from the total SO2 emissions
in the East Helena area, available evidence indicates attainment will
be met by a wide margin. We agree with MDEQ that maintenance of the
SO2 NAAQS in the East Helena SO2 maintenance area
can be tracked through updates to the emissions inventory and operating
permit applications received for SO2 emitting sources for
verification of continued attainment.
---------------------------------------------------------------------------

    \77\ Seitz Memo at 1.
---------------------------------------------------------------------------

C. EPA's Proposed Conclusion

    Based on the EPA's analysis of the East Helena SO2
Redesignation Request and Maintenance Plan, provided in

sections III.A. and III.B., the EPA is proposing to determine that the
State has met all applicable requirements of CAA sections 107(d)(3)(E)
and 175A.

IV. Proposed Action

    After review and analysis of Montana's submittal, the EPA is
proposing to redesignate the East Helena, Montana SO2 NAA to
attainment for the 1971 primary 24-hour and annual, and secondary 3-
hour SO2 NAAQS. The EPA is also proposing to approve the
State's plan for continued maintenance and attainment of the 1971
primary 24-hour and annual, and secondary 3-hour SO2 NAAQS
in East Helena, Montana for ten years following redesignation to
attainment.

V. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the Act and applicable
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely proposes to approve state law as meeting federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this proposed action:
     Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive 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 Clean Air Act; and
     Does not provide the 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 proposed to apply on any Indian
reservation land or in any other area where the 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).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Sulfur oxides.

    Authority: 42 U.S.C. 7401 et seq.

    Dated: July 11, 2019.
Gregory Sopkin,
Regional Administrator, EPA Region 8.
[FR Doc. 2019-15111 Filed 7-16-19; 8:45 am]
 BILLING CODE 6560-50-P