Document ID: EPA-R08-OAR-2019-0340-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Montana; Redesignation Request and Associated Maintenance Plan for East Helena SO2 Nonattainment Area
Posted Date: 2019-07-17T04:00Z

[Federal Register Volume 84, Number 137 (Wednesday, July 17, 2019)]
[Proposed Rules]
[Pages 34090-34102]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[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

[[Page 34091]]

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, (303) 312-7104, 
clark.adam@epa.gov, or Clayton Bean, (303) 312-6143, 
bean.clayton@epa.gov, 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

[[Page 34092]]

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

[[Page 34093]]

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

[[Page 34094]]

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.
---------------------------------------------------------------------------

    \38\ See East Helena SO2 Redesignation Request and 
Maintenance Plan, at 8.
---------------------------------------------------------------------------

    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.

[[Page 34095]]

                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

[[Page 34096]]

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

[[Page 34097]]

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

[[Page 34098]]

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

[[Page 34099]]

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

[[Page 34100]]

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.
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    \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

[[Page 34101]]

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

[[Page 34102]]

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