Approval of Arizona Air Plan Revision; San Manuel, Arizona; Second 10-Year Sulfur Dioxide Maintenance Plan, 46444-46449 [2017-21378]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 82, Number 192 (Thursday, October 5, 2017)]
[Proposed Rules]
[Pages 46444-46449]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-21378]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2017-0377; FRL-9968-89-Region 9]


Approval of Arizona Air Plan Revision; San Manuel, Arizona; 
Second 10-Year Sulfur Dioxide Maintenance Plan

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve the second 10-year maintenance plan for the San Manuel area in 
Arizona for the 1971 National Ambient Air Quality Standards (NAAQS or 
``standards'') for sulfur dioxide (SO2).

DATES: Any comments on this proposal must arrive by November 6, 2017.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2017-0377 at https://www.regulations.gov, or via email to Ashley 
Graham, Air Planning Office at graham.ashleyr@epa.gov. For comments 
submitted at Regulations.gov, follow the online instructions for 
submitting comments. Once submitted, comments cannot be removed or 
edited from Regulations.gov. For either manner of submission, 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 (e.g., audio or video) 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, please contact the person identified in the FOR FURTHER 
INFORMATION CONTACT section. For the full EPA public comment policy, 
information about CBI or multimedia submissions, and general guidance 
on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    Docket: The index to the docket for this action is available 
electronically on the www.regulations.gov Web site and in hard copy at 
EPA Region IX, 75 Hawthorne Street, San Francisco, California 94105. 
While all documents in the docket are listed in the index, some 
information may be publicly available only at the hard copy location 
(e.g., copyrighted material), and some may not be publicly available at 
either location (e.g., CBI). To inspect the hard copy materials, please 
schedule an appointment during normal business hours with the contact 
listed in the FOR FURTHER INFORMATION CONTACT section below.

FOR FURTHER INFORMATION CONTACT: Ashley Graham, EPA Region IX, (415) 
972-3877, graham.ashleyr@epa.gov.

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

Table of Contents

I. Summary of Action
II. Background

[[Page 46445]]

    A. What National Ambient Air Quality Standards are considered in 
today's rulemaking?
    B. What is a State implementation plan?
    C. What is the background for this action?
    D. What are the applicable provisions for second 10-year 
maintenance plans for SO2?
III. The EPA's Evaluation of the Arizona State Submittal
    A. Did the State meet the CAA procedural requirements?
    B. Has the State met the substantive maintenance plan 
requirements?
IV. Proposed Action and Request for Public Comment
V. Statutory and Executive Order Reviews

I. Summary of Action

    We are proposing to approve the second 10-year maintenance plan for 
the San Manuel, Arizona SO2 maintenance area (``San Manuel 
maintenance area'').\1\
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    \1\ For the definition of the San Manuel maintenance area, see 
40 CFR 81.303. The San Manuel maintenance area is located in 
southern Arizona. The EPA designated Pima and Pinal counties as 
nonattainment for SO2 on March 3, 1978, for lack of a 
state recommendation. On April 10, 1979, the EPA approved the 
State's request that the SO2-affected portion of Pima and 
Pinal counties be limited to the townships surrounding the primary 
copper smelter located near San Manuel (44 FR 21261). Townships T8S, 
R16E; T8S, R17E; T8S, R18E; T9S, R15E; T9S, R16E; T9S, R17E; T9S, 
R18E; T10S, R15E; T10S, R16E; T10S, R17E; and T11S, R16E comprised 
the nonattainment area. Townships T10S, R18E; T11S, R17E; T12S, 
R16E; and T12S, R17E were designated as ``cannot be classified.''
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II. Background

A. What National Ambient Air Quality Standards are considered in 
today's rulemaking?

    Sulfur dioxide (SO2) is the pollutant that is the 
subject of this action. The NAAQS are health-based and welfare-based 
standards for certain ambient air pollutants. Sulfur dioxide is among 
the ambient air pollutants for which we have established a health-based 
standard. Sulfur dioxide causes adverse health effects by reducing lung 
function, increasing respiratory illness, altering the lung's defenses 
and aggravating existing cardiovascular disease. Children, the elderly, 
and people with asthma are the most vulnerable. Sulfur dioxide has a 
variety of additional impacts, including acidic deposition, damage to 
crops and vegetation, and corrosion of natural and man-made materials.
    In 1971, the EPA established both short- and long-term primary 
NAAQS for SO2. The short-term (24-hour) standard of 0.14 
parts per million (ppm) was not to be exceeded more than once per year. 
The long-term standard specifies an annual arithmetic mean not to 
exceed 0.030 ppm.\2\ See 40 CFR 50.4.
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    \2\ Secondary NAAQS are promulgated to protect public welfare. 
The secondary 1971 SO2 NAAQS (3-hour) of 0.5 ppm is not 
to be exceeded more than once per year. The San Manuel area was not 
classified nonattainment for the secondary standard, and this action 
relates only to the primary 1971 SO2 NAAQS.
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    In 2010, the EPA revised the primary SO2 NAAQS by 
establishing a new 1-hour standard of 75 parts per billion. The EPA 
revoked the existing 1971 primary standards at that time because they 
would not provide additional public health protection. See 75 FR 35520 
(June 22, 2010). Today's action relates only to the revoked 1971 NAAQS. 
The State has requested that we act on this maintenance plan.\3\
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    \3\ This action is consistent with the CAA's anti-backsliding 
provisions. The EPA's final rule on revocation of the 1971 
SO2 NAAQS discussed that maintenance SIPs would continue 
being implemented by states until they are subsumed by new planning 
and control requirements associated with the revised NAAQS. See 75 
FR 35520, 35580 (June 22, 2010).
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B. What is a State implementation plan?

    The Clean Air Act (CAA or ``Act'') requires states to attain and 
maintain ambient air quality equal to or better than the NAAQS. The 
state's commitments for attaining and maintaining the NAAQS are 
outlined in the state implementation plan (SIP) for that state. The SIP 
is a planning document that, when implemented, is designed to ensure 
the achievement of the NAAQS. The Act requires that SIP revisions be 
made periodically as necessary to provide continued compliance with the 
standards.
    SIPs include, among other things, the following: (1) An inventory 
of emission sources; (2) statutes and regulations adopted by the state 
legislature and executive agencies; (3) air quality analyses that 
include demonstrations that adequate controls are in place to meet the 
NAAQS; and (4) contingency measures to be undertaken if an area fails 
to attain the standard or make reasonable progress toward attainment by 
the required date, or a contingency plan if the area fails to maintain 
the NAAQS once redesignated. The state must make the SIP available for 
public review and comment, must hold a public hearing or provide the 
public the opportunity to request a public hearing, and the SIP must be 
adopted by the state and submitted to us by the governor or her/his 
designee. The EPA acts on the SIP submittal, thus rendering the rules 
and regulations federally enforceable. The approved SIP serves as the 
state's commitment to take actions that will reduce or eliminate air 
quality problems. Any subsequent revisions to the SIP must go through 
the formal SIP revision process specified in the Act.

C. What is the background for this action?

1. When was the nonattainment area established?
    The San Manuel maintenance area is located in southern Arizona. On 
March 3, 1978, for lack of a state recommendation, the EPA designated 
Pima and Pinal counties as a primary SO2 nonattainment area 
based on monitored violations of the primary SO2 NAAQS in 
the area between 1975 and 1977. See 43 FR 8962 (March 3, 1978). At the 
request of the Arizona Department of Environmental Quality (ADEQ), the 
nonattainment area was subsequently reduced to eleven townships in and 
around San Manuel. See 44 FR 21261 (April 10, 1979). Thus, townships 
T8S, R16E; T8S, R17E; T8S, R18E; T9S, R15E; T9S, R16E; T9S, R17E; T9S, 
R18E; T10S, R15E; T10S, R16E; T10S, R17E; and T11S, R16E made up the 
nonattainment area. Townships T10S, R18E; T11S, R17E; T12S, R16E; and 
T12S, R17E were classified as ``cannot be classified'' areas.
    On the date of enactment of the 1990 CAA Amendments, SO2 
areas meeting the conditions of section 107(d) of the Act were 
designated nonattainment for the SO2 NAAQS by operation of 
law. Section 107(d) describes the processes by which nonattainment 
areas are designated, including the pre-existing SO2 
nonattainment areas. Thus, the San Manuel area remained nonattainment 
for the primary SO2 NAAQS following enactment of the 1990 
CAA Amendments on November 15, 1990.
2. When was the San Manuel area redesignated for SO2?
    During its operation, the BHP Copper Incorporated (Inc.) copper 
smelter was the largest SO2 point source in the San Manuel 
nonattainment area, contributing more than 99.5 percent of total 
SO2 emissions. The smelter was shut down in 1999, and in 
January 2005, BHP Copper Inc. notified the ADEQ that the company 
intended to permanently cease operating the smelter. In March 2005, the 
ADEQ terminated the permit for the facility, and the smelter stacks 
were dismantled in January 2007. Closure of the smelter reduced 
emissions and resultant ambient SO2 concentrations. On 
January 18, 2008, the EPA finalized approval of the maintenance plan 
and redesignation request for the San Manuel area, effective March 18, 
2008 (see 73 FR 3396).

[[Page 46446]]

3. What is the current status of the area?
    The remaining SO2 point sources in the San Manuel 
maintenance area consist of the Oracle Compressor Station, the Bonito 
Quarry, Decorative Rock Sales, Saddlebrooke Ranch Water Reclamation 
Plant, and San Manuel schools, which have a combined Potential to Emit 
(PTE) of 4.54 tons per year (tpy) SO2 (see Table 1).

   Table 1--Facility-Wide PTE for Sources Operating in the San Manuel
                            Maintenance Area
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                        Facility                          PTE  (tpy SO2)
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Oracle Compressor Station...............................            1.90
Bonito Quarry...........................................            0.80
Biosphere 2.............................................            0.71
Decorative Rock Sales...................................            0.70
Saddlebrooke Ranch Water Reclamation Plant..............            0.40
San Manuel schools......................................            0.03
                                                         ---------------
    Total...............................................            4.54
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    Currently, no ambient SO2 monitors operate in the San 
Manuel area. However, we do not expect the cumulative impact of the 
sources in San Manuel to cause a violation of the NAAQS because the 
area's emissions are sufficiently low. Monitoring data collected 
between 1975 and 2007 indicate that the primary SO2 NAAQS 
had not been violated since 1979, when the smelter was still in 
operation and emitted more than 200,000 tons of SO2. No new 
sources of SO2 of the magnitude of the BHP Copper Inc. 
smelter have located in the area since our redesignation of the area to 
attainment in 2008.

D. What are the applicable provisions for second 10-year maintenance 
plans for SO2?

1. What are the statutory provisions?
    Section 175A of the CAA provides the general framework for 
maintenance plans. The initial 10-year 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 
contingency provisions 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.
    Section 175A(b) of the CAA requires states to submit a subsequent 
maintenance plan revision (second 10-year maintenance plan) eight years 
after redesignation. The Act requires only that this second 10-year 
maintenance plan maintain the applicable NAAQS for 10 years after the 
expiration of the first 10-year maintenance plan. Beyond these 
provisions, section 175A of the CAA does not define the content of a 
second 10-year maintenance plan.
2. What general EPA guidance applies to SO2 maintenance 
plans?
    The primary guidance on maintenance plans and redesignation 
requests is a September 4, 1992, memo from John Calcagni, titled 
``Procedures for Processing Requests to Redesignate Areas to 
Attainment'' (``Calcagni Memo''). Specific guidance on SO2 
redesignations also appears in a January 26, 1995, memo from Sally L. 
Shaver, titled ``Attainment Determination Policy for Sulfur Dioxide 
Nonattainment Areas'' (``Shaver Memo'').
    While the Calcagni Memo primarily addresses redesignations, we find 
it is appropriate to apply the Calcagni Memo to second 10-year 
maintenance plans for areas that were redesignated in accordance with 
the memo and continue to experience similar conditions to those at the 
time of redesignation. For areas to qualify for redesignation to 
attainment, this policy recommends that the maintenance plan address 
otherwise applicable provisions, and include:
    (1) An attainment emissions inventory that identifies the level of 
emissions in the area that is sufficient to attain the NAAQS;
    (2) a maintenance demonstration showing that future emissions of 
the pollutant or its precursors will not exceed the level of the 
attainment inventory, or modeling to show that the future mix of 
sources and emission rates will not cause a violation of the NAAQS;
    (3) provisions for continued operation of air quality monitors to 
provide verification of the attainment status of the area;
    (4) verification that the state has the legal authority to 
implement and enforce all measures necessary to maintain the NAAQS and 
information on how the state will track the progress of the maintenance 
plan; and
    (5) contingency provisions, as necessary, to promptly correct any 
violation of the NAAQS that occurs after redesignation of the area.

III. The EPA's Evaluation of the Arizona State Submittal

A. Did the State meet the CAA procedural requirements?

    On April 21, 2017, the ADEQ submitted to the EPA the ``San Manuel 
Sulfur Dioxide Maintenance Plan Renewal, 1971 Sulfur Dioxide National 
Ambient Air Quality Standards'' (``2017 San Manuel Second Maintenance 
Plan''). The State verified that it had adhered to its SIP adoption 
procedures in Appendix B to the 2017 San Manuel Second Maintenance 
Plan, which includes the notice of public hearing; the agenda for the 
April 20, 2017 public hearing; the sign-in sheet; the public hearing 
officer certification and transcript of the hearing; and the State's 
responsiveness summary.
    The EPA reviewed the 2017 San Manuel Second Maintenance Plan for 
completeness and found the plan to be complete on September 14, 2017. 
See 40 CFR part 51, Appendix V, for the EPA's completeness criteria, 
which must be satisfied before formal review of the SIP.

B. Has the State met the substantive maintenance plan requirements?

1. Has the State met the requirements for second 10-year maintenance 
plans?
    The 2017 San Manuel Second Maintenance Plan covers the second 10 
years of the 20-year maintenance period, as required by Section 175A(b) 
of the CAA. As discussed below, the State has addressed the 
recommendations in the Calcagni Memo for emissions inventories, a 
maintenance demonstration, provisions for continued operation of air 
quality monitors, a commitment to track continued maintenance, and 
contingency provisions. We provide more details on each requirement and 
how the 2017 San Manuel Second Maintenance Plan meets each requirement 
in the following sections.
a. Attainment Emissions Inventory
    On June 7, 2007, the ADEQ submitted to the EPA its ``Final Arizona 
State Implementation Plan Revision, San Manuel Sulfur Dioxide 
Nonattainment Area'' and its request for redesignation to attainment 
(``2007 San Manuel Maintenance Plan''). The State's June 2007 submittal 
also requested that the EPA withdraw the June 2002 ``Final San Manuel 
Sulfur Dioxide Nonattainment Area State Implementation and Maintenance 
Plan.'' The June 2007 submittal updated the SIP to account for the 
closure of the dominant source of SO2 emissions, the BHP 
Copper Inc. copper smelter.

[[Page 46447]]

    The ADEQ's 2007 San Manuel Maintenance Plan included updated 
emissions inventories for sources in the San Manuel maintenance area 
for 1998, a year in which the smelter was operating and the area was 
attaining the SO2 standards, and 2005, a year in which the 
smelter was closed and the area was attaining the SO2 
standards. In the 2017 San Manuel Second Maintenance Plan, the ADEQ 
relied on the 2005 emissions inventory to demonstrate NAAQS attainment, 
and included the 1998 emissions inventory to highlight the difference 
in area emissions during a year when the smelter was operating (1998) 
and a year when the smelter had been shut down (2005). In 1998, 
emissions in the San Manuel maintenance area were approximately 10,440 
tons; in 2005, emissions were approximately 27.6 tons.
b. Maintenance Demonstration
    The Calcagni Memo recommends that a state demonstrate maintenance 
of the NAAQS by either showing that future emissions of a pollutant or 
its precursors will not exceed the level of the attainment inventory, 
or by modeling to show that the future mix of sources and emission 
rates will not cause a violation of the NAAQS.
    The 2017 San Manuel Second Maintenance Plan demonstrates continued 
maintenance of the 1971 primary SO2 NAAQS, in part, by 
showing that future emissions of SO2 will not exceed the 
level of the attainment inventory. The plan includes emissions 
inventories representing current emissions for 2014 for sources in the 
San Manuel maintenance area; projected emissions for two interim years 
during the second maintenance period (2019 and 2023); and projected 
emissions for the tenth year of the second maintenance period (2028).
    The emissions inventories in the 2017 San Manuel Second Maintenance 
Plan (see Section 3 and technical support document in Appendix A) 
include estimates of SO2 from all relevant source 
categories, which the plan divides among point, mobile (nonroad and on-
road), and area (non-point) source categories. The ADEQ used Pinal 
County's point source database to identify point sources in the Pinal 
County portion of the maintenance area. The Pinal County portion of the 
San Manuel maintenance area contains six point sources (i.e., Oracle 
Compressor Station, Bonito Quarry, Biosphere 2, Decorative Rock Sales, 
Saddlebrooke Ranch Water Reclamation Plant, and San Manuel schools), 
which together emitted 3.80 tons of SO2 in 2014. The 
combined PTE of the point sources is 4.54 tpy SO2. The 2017 
San Manuel Second Maintenance Plan includes a description of current 
facility types, permitted emissions limits, and emissions calculation 
methods for Pinal County sources. There are no point sources in the 
Pima County portion of the maintenance area.
    Mobile and area source emissions in the ADEQ's 2014 and subsequent 
year inventories were derived from the EPA's National Emissions 
Inventory Version 1 and the EPA's Motor Vehicle Emission Simulator 
model. In the 2014 base year, the ADEQ estimated that area sources 
contributed 2.58 tons of SO2, the on-road mobile source 
sector contributed 1.41 tons of SO2, and the non-road mobile 
source sector contributed 1.14 tons of SO2 in the San Manuel 
maintenance area (see Table 2).\4\ Future year SO2 emissions 
for the on-road mobile source sector are projected to decline due to 
changes in vehicle emissions standards, whereas area source emissions 
are expected to increase due to projected population growth in the San 
Manuel maintenance area. The ADEQ projected that in 2028, area sources 
will contribute 3.49 tons of SO2, on-road mobile sources 
will contribute 0.80 tons of SO2, and non-road mobile 
sources will contribute 1.65 tons of SO2 (see Table 2).
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    \4\ During the EPA's review of the ADEQ's submittal, we 
identified several inconsistencies in the 2014 population and land 
area values reported. However, the inconsistencies have only a minor 
impact, or in some cases no impact, on the emissions estimates 
derived. In cases where discrepancies did have a minor impact on 
emissions estimates, the EPA found that they led to an overestimate 
in SO2 emissions and thus do not alter the ADEQ's 
findings that emissions through 2028 are projected to be well below 
the 2005 attainment inventory emissions, and that emissions 
estimates demonstrate continued attainment of the 1971 
SO2 NAAQS in the San Manuel maintenance area. See 
memorandum dated June 21, 2017, from Ashley Graham, EPA Region 9, 
Air Planning Office, to docket EPA-R09-OAR-2017-0377, ``Technical 
note regarding emissions inventories in Arizona's San Manuel 
SO2 2nd 10-year maintenance plan.''

                           Table 2--San Manuel Maintenance Area SO2 Emissions Summary
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                                       2005            2014            2019            2023            2028
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Area............................              27            2.58            2.86            3.12            3.49
On-road Mobile..................                            1.41            0.72            0.75            0.80
Non-road Mobile.................                            1.14            1.30            1.45            1.65
Point...........................             0.6            3.80            4.54            4.54            4.54
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    Total.......................            27.6            8.92            9.43            9.86           10.48
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    Based on our review of the emissions inventories in the 2017 San 
Manuel Second Maintenance Plan, including the supporting information in 
Appendix A, we conclude that the inventories are complete and 
consistent with applicable CAA provisions and the Calcagni Memo.
    As discussed above, no new sources of SO2 that are 
similar in size to the BHP Copper Inc. copper smelter have located in 
the area since our redesignation of the area to attainment in 2008. The 
submittal shows that the current (2014) and maximum expected level of 
emissions in the San Manuel SO2 maintenance area through the 
end of the maintenance period (2028) are projected to be well below 
both the 1998 and 2005 attainment inventories. In 2005, emissions were 
27.6 tons of SO2; 2014 emissions were 8.92 tons of 
SO2; and 2028 emissions are projected to be 10.48 tons of 
SO2.\5\
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    \5\ See footnote 4.
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    The Calcagni Memo also specifies that projected emissions should 
reflect permanent, enforceable measures. Emission reductions from 
source shutdowns are considered permanent and enforceable if the 
shutdowns have been reflected in the SIP and all applicable permits 
have been modified accordingly. The ADEQ terminated the permit for the 
BHP Copper Inc. copper smelter in March 2005, and the smelter stacks 
were dismantled in January 2007. The smelting facility cannot reopen 
without submitting New Source Review (NSR) and Title V (Part 70) permit 
applications to the ADEQ. We therefore propose to conclude that the 
State has demonstrated that the 1971 SO2 NAAQS

[[Page 46448]]

is adequately protected due to permanent and enforceable measures.
c. Air Quality Monitoring
    The Calcagni Memo recommends that once an area has been 
redesignated from nonattainment to maintenance, the state should 
continue to operate the appropriate air quality monitoring network to 
allow for continued verification of the attainment status of the area. 
However, following five years of clean data, SO2 monitors 
were removed from the San Manuel area in accordance with 40 CFR 
58.14(c)(3). Monitoring data collected during 1997 through 1999, while 
the smelter was still operating, indicate that maximum ambient 
SO2 concentrations were less than 55 percent of the 3-hour 
NAAQS, less than 59 percent of the 24-hour NAAQS, and less than 33 
percent of the annual NAAQS. Closure of the smelter in 1999 reduced 
emissions and resultant ambient SO2 concentrations. 
Monitoring data for 2002 through 2007 indicate that maximum ambient 
SO2 concentrations were two percent of the 3-hour NAAQS, 
less than three percent of the 24-hour NAAQS, and less than seven 
percent of the annual NAAQS.
    The ADEQ does not anticipate a substantial increase in point source 
emissions in future years and commits to resume monitoring before any 
major source of SO2 commences to operate in the San Manuel 
maintenance area. See 2017 San Manuel Second Maintenance Plan, p. 41. 
Since there are no remaining sources of SO2 emissions of the 
magnitude of BHP Copper Inc., the projected future emissions through 
2028 are sufficiently low relative to emissions during the 1998 and 
2005 attainment years, and we do not anticipate any reason the 1971 
SO2 NAAQS would be violated, we conclude that future 
monitoring per the recommendations in the Calcagni Memo is not required 
and that the State's commitment to resume monitoring before any major 
source of SO2 commences to operate in the San Manuel area 
satisfactorily addresses the CAA provisions.
d. Verification of Continued Attainment
    The Calcagni Memo recommends that states ensure that they have the 
legal authority to implement and enforce all measures necessary to 
maintain the NAAQS, and that they specify how they will track progress 
of the maintenance plan in their submittal. One option for tracking 
maintenance would be through periodic updates to the emissions 
inventory.
    The 2017 San Manuel Second Maintenance Plan submittal notes that 
the ADEQ, the Pima County Department of Environmental Quality (PDEQ), 
and the Pinal County Air Quality Control District (PCAQCD) have 
permitting and planning jurisdiction in the San Manuel SO2 
maintenance area and general authority to implement and enforce all 
measures to maintain the 1971 SO2 NAAQS per Arizona Revised 
Statutes (A.R.S.) Sec. Sec.  49-104, 49-404, 49-422, and 49-424.
    In the 2017 San Manuel Second Maintenance Plan, the State commits 
to track maintenance of the SO2 NAAQS in the San Manuel area 
through updates to the annual statewide emissions inventory and review 
of permit applications for SO2 sources. See 2017 San Manuel 
Second Maintenance Plan, p. 42. Permitted sources are subject to 
monitoring, reporting, and certification procedures contained in 
Arizona Administrative Code (A.A.C) R18-2-306 and R18-2-309. The ADEQ 
has authority to monitor and ensure compliance with all applicable 
rules and permit conditions for sources in its jurisdiction, pursuant 
to A.R.S. Sec.  49-101. The PCAQCD and the PDEQ have authority for 
sources under their jurisdiction under A.R.S. Sec.  49-402. We find 
that the State's continued commitment to track maintenance of the 
SO2 NAAQS through updates to the emissions inventory and the 
State's prevention of significant deterioration (PSD) permitting 
programs are sufficient to assure that the San Manuel area will 
maintain the NAAQS.
e. Contingency Plan
    Section 175A(d) of the CAA requires that maintenance plans contain 
contingency provisions deemed necessary by the Administrator to assure 
that the state will promptly correct any violation of the standard that 
occurs after the redesignation of the area as an attainment area. The 
Calcagni Memo provides additional guidance, noting that although a 
state is not required to have fully-adopted contingency measures that 
will take effect without further action by the state for the 
maintenance plan to be approved, the maintenance plan should ensure 
that the contingency measures are adopted expediently once they are 
triggered. Specifically, the maintenance plan should clearly identify 
the measures to be adopted, include a schedule and procedure for 
adoption and implementation of the measures, and contain a specific 
time limit for action by the state. In addition, the state should 
identify specific indicators or triggers, that will be used to 
determine when the contingency measures need to be implemented.
    Since there are no remaining sources of SO2 emissions of 
the magnitude of the BHP Copper Inc. copper smelter, the primary cause 
of any future violations of the 1971 SO2 NAAQS in the San 
Manuel area would be from new or modified point sources. The ADEQ and 
the PDEQ have PSD permitting programs (i.e., A.A.C. R18-2-406 and Pima 
County Code 17.16.590) that were established to preserve the air 
quality in areas where ambient standards have been met. The PCAQCD's 
PSD program is under the ADEQ's jurisdiction. The ADEQ has jurisdiction 
over all refineries, copper smelters, coal-fired power plants, cement 
plants, and portable sources that will operate in multiple counties 
(see A.R.S. 49-402). These sources must obtain permits from the ADEQ. 
The State's updated PSD program was approved into the SIP on November 
2, 2015 (80 FR 67319). Although the PDEQ's PSD program is not SIP-
approved, the federal PSD permitting program at 40 CFR 52.21 was 
delegated to the PDEQ effective April 14, 1994. The PSD programs apply 
to any major source or major modification in the San Manuel area. 
Should a new facility be constructed in the San Manuel area or an 
existing facility want to upgrade or increase SO2 emissions, 
the facility would be subject to PSD as recommended in the Calcagni 
Memo.
    Furthermore, the ADEQ anticipates no relaxation of any implemented 
control measures used to attain and maintain the NAAQS, and commits to 
submit to us any changes to rules or emission limits applicable to 
SO2 sources, as well as committing to maintain the necessary 
resources to promptly correct any violations of the provisions 
contained in the 2017 San Manuel Second Maintenance Plan.
    Upon review of the contingency plan summarized above, we find that 
the ADEQ has established a contingency plan for the San Manuel area 
that satisfies the requirements of CAA section 175A(d) and the Calcagni 
Memo.
2. Other CAA Requirements
a. Transportation and General Conformity
    As discussed above, section 175A of the CAA sets forth the 
statutory requirements for maintenance plans, and the Calcagni and 
Shaver memos cited above contain specific EPA guidance. Additional 
maintenance plan elements not covered by the Calcagni Memo are the 
transportation and general conformity provisions.
    Conformity is required under section 176(c) of the CAA to ensure 
that federal actions are consistent with (``conform

[[Page 46449]]

to'') the purpose of the SIP. Conformity to the purpose of the SIP 
means that federal activities will not cause new air quality 
violations, worsen existing violations, or delay timely attainment of 
the relevant NAAQS or interim reductions and milestones. Conformity 
applies to areas that are designated nonattainment and to maintenance 
areas. The requirement to determine conformity applies to 
transportation plans, programs, and projects developed, funded, or 
approved under Title 23 U.S.C. and the Federal Transit Act 
(``transportation conformity''), as well as to other federally 
supported or funded projects (``general conformity'').
    Transportation conformity applies to projects that require Federal 
Highway Administration or Federal Transit Administration funding. 40 
CFR part 93 describes the requirements for federal actions related to 
transportation plans, programs, and projects to conform to the purposes 
of the SIP. Because the EPA does not consider SO2 a 
transportation-related criteria pollutant,\6\ only the requirements 
related to general conformity apply to the San Manuel area.
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    \6\ See 40 CFR 93.102(b)(1).
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    Section 176(c)(4) of the CAA establishes the framework for general 
conformity. Besides ensuring that federal actions not covered by the 
transportation conformity rule will not interfere with the SIP, the 
general conformity regulations encourage consultation between the 
federal agency and the state or local air pollution control agencies 
before and during the environmental review process; public notification 
of and access to federal agency conformity determinations; and air 
quality review of individual federal actions.
    Section 176(c) of the CAA requires states to revise their SIPs to 
establish criteria and procedures to ensure that federally supported or 
funded projects in nonattainment and maintenance areas ``conform'' to 
the air quality planning goals in the applicable SIP. SIP revisions 
intended to meet the conformity requirements in section 176(c) are 
referred to as ``conformity SIPs.'' In 2005, Congress amended section 
176(c). Under the amended conformity provisions, states are no longer 
required to submit conformity SIPs for general conformity, and the 
conformity SIP requirements for transportation conformity have been 
reduced to include only those relating to consultation, enforcement, 
and enforceability. See CAA section 176(c)(4)(E).
    The EPA believes it is reasonable to interpret the conformity SIP 
requirements as not applying for purposes of a redesignation request 
under section 107(d)(3)(E)(v) because 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). Because the San Manuel area has already been redesignated 
for this standard, we believe it is reasonable to apply the 
interpretation of conformity SIP requirements as not applying for the 
purposes of redesignation to the approval of the second 10-year 
maintenance plan.
    Criteria for making determinations and provisions for general 
conformity are contained in A.A.C. R18-2-1438. Arizona has an approved 
general conformity SIP.\7\
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    \7\ See 64 FR 19916 (April 23, 1999).
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    The ADEQ commits in the 2017 San Manuel Second Maintenance Plan to 
review and comment, as appropriate, on any federal agency draft general 
conformity determination it receives consistent with 40 CFR 93.155 for 
any federal plans or actions in this planning area, although none are 
currently planned for the area. See 2017 San Manuel Second Maintenance 
Plan, p. 18.

IV. Proposed Action and Request for Public Comment

    We propose to approve the second 10-year SO2 maintenance 
plan for the San Manuel area in Arizona under sections 110 and 175A of 
the CAA. As authorized in section 110(k)(3) of the Act, the EPA is 
proposing to approve the submitted SIP because we believe it fulfills 
all relevant requirements.
    We will accept comments from the public on this proposal for 30 
days from the date of publication of this notice, and we will consider 
any relevant comments in taking final action on today's proposal.

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable federal regulations. See 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 Clean Air Act. 
Accordingly, this action merely approves state law as meeting federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this action:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     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).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Reporting and recordkeeping 
requirements, Sulfur dioxide.

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

    Dated: September 26, 2017.
Alexis Strauss,
Acting Regional Administrator, EPA Region IX.
[FR Doc. 2017-21378 Filed 10-4-17; 8:45 am]
 BILLING CODE 6560-50-P