Document ID: EPA-R09-OAR-2018-0222-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Arizona Air Plan; Hayden Lead Nonattainment Area Plan for 2008 Lead Standard
Posted Date: 2018-07-03T04:00Z

[Federal Register Volume 83, Number 128 (Tuesday, July 3, 2018)]
[Proposed Rules]
[Pages 31087-31098]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-14198]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2018-0222; FRL-9980-21--Region 9]

Approval of Arizona Air Plan; Hayden Lead Nonattainment Area Plan 
for the 2008 Lead Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a state implementation plan (SIP) revision submitted by the 
State of Arizona to meet Clean Air Act (CAA or ``Act'') requirements 
applicable to the Hayden lead (Pb) nonattainment area (``Hayden Lead 
NAA''). The EPA is proposing to approve the base year emissions 
inventory, the attainment demonstration, the control strategy, 
including reasonably available control technology and reasonably 
available control measures demonstrations, the reasonable further 
progress demonstration, the contingency measure, and the new source 
review (NSR) provisions of the submittal as meeting the requirements of 
the CAA and the EPA's implementing regulations for the 2008 lead 
national ambient air quality standard (NAAQS).

DATES: Any comments on this proposal must arrive by August 2, 2018.

ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2018-0222, at http://www.regulations.gov, or via email to 
[email protected]. For comments submitted at Regulations.gov, 
follow the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed 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 (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, please contact the person 
identified in the FOR FURTHER INFORMATION CONTACT section. For the 
EPA's full 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.

FOR FURTHER INFORMATION CONTACT: Ginger Vagenas, EPA Region IX, 415-
972-3964, [email protected]

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

Table of Contents

I. Background
    A. The Lead NAAQS
    B. Designation of the Hayden Lead NAA
    C. CAA Requirements for Lead Nonattainment Areas
    D. Sources of Lead in the Hayden Lead NAA
II. Arizona's SIP Submittal To Address the Hayden Lead NAA
    A. Arizona's SIP Submittal
    B. CAA Procedural and Administrative Requirements for SIP 
Submittals
III. CAA and Regulatory Requirements for Lead Attainment SIPs
    A. CAA and EPA Guidance
    B. Infrastructure SIPs for Lead
IV. Review of the 2017 Hayden Lead Plan
    A. Summary of the EPA's Proposed Actions
    B. Emissions Inventories
    C. Reasonably Available Control Measure/Reasonably Available 
Control Technology Demonstration and Adopted Control Strategy
    D. Attainment Demonstration
    E. Reasonable Further Progress Demonstration
    F. Contingency Measures
    G. New Source Review
V. The EPA's Proposed Action and Request for Public Comments
    A. The EPA's Proposed Approvals
    B. Request for Public Comments
VI. Statutory and Executive Order Reviews

I. Background

A. The Lead NAAQS

    Under the CAA, the EPA must establish NAAQS for six pollutants, 
including lead. Lead is generally emitted in the form of particles that 
are deposited in water, soil, and dust. People may be exposed to lead 
by inhaling it or by ingesting lead-contaminated food, water, soil, or 
dust. Once in the body, lead is quickly absorbed into the bloodstream 
and can result in a broad range of adverse health effects including 
damage to the central nervous system, cardiovascular function, kidneys, 
immune system, and red blood cells. Children are particularly 
vulnerable to lead exposure, in part because they are more likely to 
ingest lead and in part because their still-developing bodies are more 
sensitive to the effects of lead. The harmful effects to children's 
developing nervous systems (including their brains) arising from lead 
exposure may include IQ \1\ loss, poor academic achievement, long-term 
learning disabilities, and an increased risk of delinquent behavior.
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    \1\ IQ (intelligence quotient) is a score created by dividing a 
person's mental age score, obtained by administering an intelligence 
test, by the person's chronological age, both expressed in terms of 
years and months. ``Glossary of Important Assessment and Measurement 
Terms,'' Philadelphia, PA: National Council on Measurement in 
Education. 2016.
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    The EPA first established a lead standard in 1978 at 1.5 micrograms 
per meter cubed ([micro]g/m\3\) as a quarterly average.\2\ Based on new 
health and scientific data, the EPA revised the federal lead standard 
to 0.15 [micro]g/m\3\ and revised the averaging time for the standard 
on October 15, 2008.\3\ A violation of the standard occurs when ambient 
lead concentrations exceed 0.15

[[Page 31088]]

[micro]g/m\3\ averaged over a 3-month rolling period.
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    \2\ See 43 FR 46246 (October 5, 1978).
    \3\ See 73 FR 66964 (November 12, 2008) (``lead NAAQS rule'').
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B. Designation of the Hayden Lead NAA

    The process for designating areas following promulgation of a new 
or revised NAAQS is set forth in section 107(d) of the CAA. The CAA 
requires the EPA to complete the initial area designations process 
within two years of promulgating a new or revised NAAQS. Section 107(d) 
of the CAA allows the EPA to extend the period for initial designations 
for up to a year in cases where the available information is 
insufficient to promulgate designations. The initial designations for 
the 2008 lead NAAQS were established in two rounds and were completed 
on November 22, 2010 and November 22, 2011.\4\ The EPA initially 
designated the Hayden, Arizona area as unclassifiable due to 
insufficient monitoring data.\5\
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    \4\ See 75 FR 71033 and 76 FR 72097.
    \5\ Arizona Department of Environmental Quality's Globe Highway 
monitor registered four violations of the lead NAAQS in 2011; 
however, at the time of designation the data had not been quality 
assured and certified. Consequently, we did not rely on them as the 
basis for a nonattainment designation.
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    The CAA grants the EPA the authority to change the designation of 
areas (``redesignate'') in light of changes in circumstances. More 
specifically, the EPA has the authority under CAA section 107(d)(3) to 
redesignate areas based on air quality data, planning, and control 
considerations, or any other air quality-related considerations. In 
June 2013, we determined that quality assured, certified monitoring 
data collected in 2012 at the Arizona Department of Environmental 
Quality (ADEQ or ``State'') Globe Highway monitor showed that the area 
was violating the lead NAAQS. Accordingly, on May 2, 2014, the EPA 
issued a proposal to redesignate the Hayden area to nonattainment for 
the 2008 lead NAAQS. That proposal was finalized on September 3, 2014, 
effective October 3, 2014.6 7
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    \6\ See 79 FR 52205.
    \7\ For an exact description of the Hayden Lead NAA, see 40 CFR 
81.303.
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C. CAA Requirements for Lead Nonattainment Areas

    Designation of an area as nonattainment starts the process for a 
state to develop and submit to the EPA a SIP under title 1, part D of 
the CAA. Under CAA sections 191(a) and 192(a), attainment demonstration 
SIPs for the lead NAAQS are due 18 months after the effective date of 
an area's nonattainment designation and must provide for attainment of 
the standard as expeditiously as practicable, but no later than five 
years after designation.\8\ The CAA requires that the SIP include 
emissions inventories, a reasonable further progress (RFP) 
demonstration, a reasonably available control measures/reasonably 
available control technology (RACM/RACT) demonstration, an attainment 
demonstration, and contingency measures. In general, to demonstrate 
timely attainment, control measures need to be implemented as 
expeditiously as practicable.
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    \8\ For the Hayden Lead NAA, the attainment date is October 3, 
2019.
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D. Sources of Lead in the Hayden Lead NAA

    Stationary sources of lead are generally large industrial sources, 
including metals processing, particularly primary and secondary lead 
smelters. Lead can also be emitted by iron and steel foundries, primary 
and secondary copper smelters, industrial, commercial and institutional 
boilers, waste incinerators, glass manufacturing, refineries, and 
cement manufacturing. ADEQ has determined that the cause of the 
nonattainment status in the Hayden area is the primary copper smelter 
owned and operated by ASARCO, LLC (``Asarco''). The State notes that 
this facility ``accounts for over 99 percent of Pb emissions'' and that 
the ``[e]missions generally come from the hot-metal smelting process 
and lead-bearing fugitive dust.'' \9\
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    \9\ Plan, page 38.
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    Because regional ambient air lead concentrations indicate low 
ambient lead levels relative to the 2008 lead NAAQS, and because the 
only ambient levels exceeding the NAAQS were at sites near the Asarco 
facility, ADEQ's lead attainment strategy is focused on reducing lead 
emissions generated by this source.

II. Arizona's SIP Submittal To Address for the Hayden Lead NAA

A. Arizona's SIP Submittal

    ADEQ is the air quality agency that develops SIPs for the Hayden 
area. The SIP for the Hayden Lead NAA, entitled ``SIP Revision: Hayden 
Lead Nonattainment Area'' (``2017 Hayden Lead Plan'' or ``Plan'') was 
due April 3, 2016. It was adopted by ADEQ on March 3, 2017, and 
submitted to the EPA on the same day.\10\
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    \10\ See letter dated March 3, 2017, from Timothy S. Franquist, 
Director, Air Quality Division, ADEQ, to Alexis Strauss, Acting 
Regional Administrator, EPA Region IX.
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B. CAA Procedural and Administrative Requirements for SIP Submittals

    CAA sections 110(a)(1) and (2) and 110(l) require a state to 
provide reasonable public notice and opportunity for public hearing 
prior to the adoption and submittal of a SIP or SIP revision. To meet 
this requirement, every SIP submittal should include evidence that 
adequate public notice was given and a public hearing was held 
consistent with the EPA's implementing regulations in 40 CFR 51.102.
    ADEQ has satisfied applicable statutory and regulatory requirements 
for reasonable public notice and hearing prior to adoption and 
submittal of the 2017 Hayden Lead Plan. The State provided a public 
comment period and held a public hearing prior to the adoption of the 
Plan on March 3, 2017. The SIP submittal includes notices of the 
State's public hearing as evidence that the hearing was properly 
noticed.\11\ We therefore find that the submittal meets the procedural 
requirements of CAA sections 110(a) and 110(l).
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    \11\ See 2017 Hayden Lead Plan, Appendix F, Public Process 
Documentation.
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    CAA section 110(k)(1)(B) requires the EPA to determine whether a 
SIP submittal is complete within 60 days of receipt. This section also 
provides that any plan that the EPA has not affirmatively determined to 
be complete or incomplete will become complete six months after the 
date of submittal by operation of law. The EPA's SIP completeness 
criteria are found in 40 CFR part 51, appendix V. The 2017 Hayden Plan 
became complete by operation of law on September 3, 2017.

III. CAA and Regulatory Requirements for Lead Attainment SIPs

A. CAA and EPA Guidance

    Requirements for the lead NAAQS are set forth in title 1, part D, 
subparts 1 and 5 of the CAA, which includes section 172, 
``Nonattainment plan provisions in general,'' and sections 191 and 192, 
``Plan submission deadlines'' and ``Attainment dates,'' respectively.
    Section 192(a) establishes that the attainment date for lead 
nonattainment areas is ``as expeditiously as practicable'' but no later 
than five years from the date of the nonattainment designation for the 
area. The EPA designated the Hayden area as a nonattainment area 
effective October 3, 2014, and thus the applicable attainment date is 
no later October 3, 2019. Under section 172(a)(2)(D), the Administrator 
is precluded from granting an extension of this attainment date because 
the statute separately establishes a specific attainment date in 
section 192(a).
    Section 172(c) contains the general statutory planning requirements 
applicable to all nonattainment areas,

[[Page 31089]]

including the requirements for emissions inventories, RACM/RACT, 
attainment demonstrations, RFP demonstrations, and contingency 
measures. When the EPA issued the lead NAAQS rule, we included some 
guidelines for implementing these planning requirements.\12\ The EPA 
also issued several guidance documents related to planning requirements 
for the lead NAAQS.\13\ These include:
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    \12\ See 73 FR 66964.
    \13\ These guidance documents can be found in the docket for 
today's action.
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     ``2008 Lead (Pb) National Ambient Air Quality Standards 
(NAAQS) Implementation Questions and Answers,'' Memorandum from Scott 
L. Mathias, Interim Director, Air Quality Policy Division, EPA Office 
of Air Quality Planning and Standards, to Regional Air Division 
Directors, Regions I-X, July 8, 2011, (``Lead Q&A''); and
     ``Addendum to the 2008 Lead NAAQS Implementation Questions 
and Answers Signed on July 11, 2011, by Scott Mathias,'' August 10, 
2012. (``Lead Q&A Addendum''); and
     Implementation of the 2008 Lead National Ambient Air 
Quality Standards--Guide to Developing Reasonably Available Control 
Measures (RACM) for Controlling Lead Emissions, EPA Office of Air 
Quality Planning and Standards, EPA-457/R-12-001, March 2012 (``Lead 
RACM Guidance'').
    The lead NAAQS rule and its preamble and the guidance documents 
address the statutory planning requirements for emissions inventories, 
RACM/RACT, attainment demonstrations including air quality modeling 
requirements, RFP demonstrations, and contingency measures. The lead 
NAAQS rule also addresses other matters such as monitoring, 
designations, lead infrastructure SIPs, and exceptional events. We will 
discuss each of the CAA and regulatory requirements for lead attainment 
plans in the next section, which details our review of the 2017 Hayden 
Lead Plan.

B. Infrastructure SIPs for Lead

    Under section 110 of the CAA, all states (including those without 
nonattainment areas) are required to submit infrastructure SIPs within 
three years of the promulgation of a new or revised NAAQS. Because the 
lead NAAQS was signed and widely disseminated on October 15, 2008, the 
infrastructure SIPs were due by October 15, 2011. Section 110(a)(1) and 
(2) require states to address basic program elements, including 
requirements for emissions inventories, monitoring, and modeling, among 
other things. Subsections (A) through (M) of section 110(a)(2) set 
forth the elements that a state's program must contain in the SIP. 
Arizona's lead infrastructure SIP was approved by the EPA on August 10, 
2015.\14\
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    \14\ 80 FR 47859.
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IV. Review of the 2017 Hayden Lead Plan

A. Summary of the EPA's Proposed Actions

    The EPA is proposing to approve the 2017 Hayden Lead Plan. We are 
proposing to approve the 2012 base year emissions inventory in this SIP 
revision as meeting the applicable requirements of the CAA and EPA 
guidance. We are also proposing to approve the attainment 
demonstration, RACM/RACT analysis, RFP demonstration, and the 
contingency measure as meeting the applicable requirements of the CAA 
and EPA guidance.
    The EPA's analysis and findings are discussed below for each 
applicable requirement. The technical support document (TSD) for 
today's proposed action contains additional details on selected lead 
planning requirements.

B. Emissions Inventories

1. Requirements for Emissions Inventories
    The emissions inventory and source emission rate data for an area 
serve as the foundation for air quality modeling and other analyses 
that enable states to estimate the degree to which different sources 
within a nonattainment area contribute to violations within the 
affected area. These analyses also enable states to assess the expected 
improvement in air quality within the nonattainment area due to the 
adoption and implementation of control measures. CAA section 172(c)(3) 
requires that states submit a ``comprehensive, accurate, current 
inventory of actual emissions from all sources of the relevant 
pollutant.'' Therefore, all sources of lead emissions in the 
nonattainment area must be included in the submitted inventory. A base 
year emissions inventory is required for the attainment demonstration 
and for meeting RFP requirements. In general, the base year emissions 
inventory should be derived from one of the years on which the 
nonattainment designation was based.\15\
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    \15\ See Lead Q&A and Lead Q&A Addendum.
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    In order to demonstrate attainment in accordance with CAA section 
172, the state should also provide an attainment emissions inventory to 
identify the level of emissions in the area sufficient to attain the 
NAAQS. The attainment inventory should generally contain maximum 
allowable emissions for the attainment year for all sources within the 
modeling domain.\16\
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    \16\ See Lead Q&A Addendum p. 1.
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    In addition to inventory reporting requirements in CAA section 
172(c)(3), 40 CFR 51.117(e)(1) requires that the inventory contain all 
point sources that emit 0.5 tons of lead emissions per year (tpy).\17\ 
Based on annual emissions reporting for 2011, the only point source in 
the Hayden Lead NAA with a potential to emit over 0.5 tpy of lead is 
the Asarco primary copper smelter, located in Hayden, AZ (``Hayden 
Facility'' or ``Facility'').\18\
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    \17\ Additional emissions inventory reporting requirements are 
also found in EPA's Air Emissions Reporting Rule (AERR) (codified at 
40 CFR part 51 subpart A) and 73 FR 76539. Although the AERR 
requirements are separate from the SIP-related requirements in CAA 
section 172(c)(3) and 40 CFR 51.117(e)(1), the AERR requirements are 
intended to be compatible with the SIP-related requirements.
    \18\ The Asarco primary copper smelter is a large complex that 
consists of smelter operations as well as concentrator operations. 
In sections of the Plan, ADEQ refers to these operations separately 
as the ``smelter complex'' and ``concentrator complex.'' Since the 
smelter and concentrator operations are permitted as a single 
stationary source, we use the term ``Hayden Facility'' and 
``Facility'' to refer to the entirety of the smelter and 
concentrator operations.
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2. Base Year Emissions Inventory
    The base year emissions inventory establishes a baseline that is 
used to evaluate emission reductions achieved by the control strategy 
and to establish RFP requirements. ADEQ's discussion of emissions 
inventory development can be found in the Plan on pages 28-36, as well 
as in Appendices A and D. ADEQ selected 2012 as the base year for 
emissions inventory preparation for several reasons. At time of 
preparation, 2012 was the most recent year with verified ambient air 
monitoring data from a SLAMS (State or Local Air Monitoring Station) 
monitor.\19\ It is also a representative year of exceedances of the 
primary lead NAAQS. In addition, the Hayden lead nonattainment 
designation was based upon 2012 monitoring data.
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    \19\ SLAMS include the ambient air quality sites and monitors 
that are required by the EPA's regulations and are needed to meet 
specific monitoring objectives, including NAAQS comparisons. See 40 
CFR 58.1.
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    Lead emissions are grouped into two general categories: Stationary 
and mobile sources. Stationary sources can be further divided into 
``point'' and ``area'' sources. Point sources are typically located at 
permitted facilities and have one or more identified and fixed pieces 
of equipment and

[[Page 31090]]

emissions points. These facilities are required to report their 
emissions to ADEQ on an annual basis. Conversely, area sources consist 
of widespread and numerous smaller emission sources, such as small 
permitted facilities, households, and other land uses. The mobile 
sources category can be divided into two major subcategories: ``On-
road'' and ``off-road'' mobile sources. On-road mobile sources include 
light-duty automobiles, light-, medium-, and heavy-duty trucks, and 
motorcycles. Off-road mobile sources include aircraft, locomotives, 
construction equipment, mobile equipment, and recreational vehicles. A 
summary of ADEQ's 2012 base year inventory for each of these categories 
is included in Table 1 below.

 Table 1--2012 Base Year Lead Emission Inventory for the Hayden Lead NAA
------------------------------------------------------------------------
                                                           Pb emissions
                     Source category                           (tpy)
------------------------------------------------------------------------
Point...................................................            3.43
Area....................................................          <0.001
Mobile Source (non-road)................................           0.015
Mobile Source (on-road).................................
                                                         ---------------
    Total...............................................            3.45
------------------------------------------------------------------------
Source: Plan, Tables 12-16.

    As seen above, the substantial majority of lead emissions in the 
Hayden Lead NAA are from the point source category (i.e., the Hayden 
Facility). The Hayden Facility consists of multiple emission points 
that ADEQ further categorized into smelting point sources (stack 
emissions), smelting fugitives, road dust, and other process fugitives 
(from non-smelting process equipment). A more detailed summary of the 
Hayden Facility's lead emissions is included in Table 2 below.

Table 2--2012 Base Year Lead Emissions Inventory for the Hayden Facility
------------------------------------------------------------------------
                                                           Pb emissions
                     Source category                           (tpy)
------------------------------------------------------------------------
Smelting point sources..................................            1.09
Smelting fugitives......................................            1.88
Road (paved and unpaved)................................            0.14
Non-smelting process fugitives..........................            0.32
                                                         ---------------
    Total...............................................            3.43
------------------------------------------------------------------------
Source: Id.

3. Projected Year Emissions Inventory
    The Hayden area was designated nonattainment for lead in 2014. The 
CAA provides that nonattainment areas must attain the NAAQS as 
expeditiously as practicable, but no later than five years after the 
effective date of designation. Therefore, the Hayden Lead NAA must 
attain the lead NAAQS by 2019. The projected emissions inventory for 
2019 is part of the attainment demonstration required under CAA section 
172 and informs the air quality modeling for 2019, which is discussed 
in detail below in section IV.D. ADEQ developed a projected 2019 lead 
emissions inventory for the Hayden Lead NAA as summarized in Table 3 
below.

             Table 3--Base Year and Projected Year Lead Emissions Inventory for the Hayden Lead NAA
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                                                                   2012 base year Pb      2019 projected year Pb
                        Source category                         emissions (tpy) (actual      emissions (tpy)
                                                                       emissions)         (allowable emissions)
----------------------------------------------------------------------------------------------------------------
Point.........................................................                     3.43                     4.60
Area..........................................................                   <0.001                   <0.001
Mobile Source (non-road)......................................                    0.015                    0.020
Mobile Source (on-road).......................................
                                                               -------------------------------------------------
    Total.....................................................                     3.45                     4.62
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Source: Id.

    As with the base year inventory, the substantial majority of lead 
emissions for the projected year inventory are attributable to the 
point source category, which represents the Hayden Facility. A more 
detailed summary of the Hayden Facility's lead emissions is included in 
Table 4 below.

      Table 4--Comparison of Base Year and Projected Year Lead Emissions Inventory for the Hayden Facility
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                                                                   2012 base year Pb      2019 projected year Pb
                        Source category                         emissions (tpy) (actual      emissions (tpy)
                                                                       emissions)         (allowable emissions)
----------------------------------------------------------------------------------------------------------------
Smelting point sources........................................                     1.09                     2.99
Smelting fugitives............................................                     1.88                     1.44
Road (paved and unpaved)......................................                    0.137                    0.043
Non-smelting fugitives........................................                    0.322                    0.131
                                                               -------------------------------------------------
    Total.....................................................                     3.43                     4.60
----------------------------------------------------------------------------------------------------------------
Source: Id.

    As seen in the tables above, the projected year emissions 
inventory, which is generally based on maximum allowable emissions 
(also referred to as potential to emit or PTE), is higher than the base 
year inventory, which is based on actual emissions. The use of actual 
emissions for the base year, as well as the use of maximum allowable

[[Page 31091]]

emissions for the projection year and the attainment modeling, is 
consistent with CAA requirements \20\ and EPA guidance.\21\ Use of 
maximum allowable emissions for the modeling ensures the attainment 
demonstration takes into account possible increases in emissions that 
are allowed by the underlying rules and permit conditions; however, 
actual emissions at the Facility are expected to decline. As shown in 
Table 5, the 2019 projected actual emissions are lower than actual 
emissions in the 2012 base year inventory. Furthermore, even assuming 
that the Facility were to emit at the maximum allowable levels in 2019, 
the submitted modeling shows that the Hayden area would still attain 
the lead NAAQS, primarily due to the nature of emission changes and 
their predicted ambient impact. The increase from base year actual 
emissions to projected year maximum allowable emissions is primarily 
attributable to smelting point sources at the Hayden Facility. Other 
source categories at the Facility, such as the roads and non-smelting 
fugitives, decrease from the base year inventory to the projected year 
inventory, and, due to their dispersion characteristics, these sources 
have more influence on the maximum predicted ambient impacts in the 
nonattainment area than the smelter point sources. As a result, while 
the reductions in road and non-smelting fugitive lead emissions are 
small compared to the emissions from the smelting point sources, these 
reductions occur at sources that are primary contributors to maximum 
predicted ambient impact in the nonattainment area.
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    \20\ See, e.g., CAA section 172(c)(3) (requiring ``a 
comprehensive, accurate, current inventory of actual emissions from 
all sources of the relevant pollutant or pollutants in such area.'' 
(emphasis added))
    \21\ See, e.g., Lead Q&A Addendum p. 1.

                                   Table 5--Base Year, Projected Actual, and Maximum Allowable Modeled Lead Emissions
                                                                 for the Hayden Facility
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                                                                                                            Projected
                                                       2012 actual Pb      2019 projected actual Pb       reductions in   Maximum allowable- modeled Pb
         Modeled source             Controls applied      emissions             emissions (tpy)             actual Pb       emissions (PTE) (tpy) \a\
                                                            (tpy)                                         emissions (%)
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Main stack......................  Secondary hood                 1.08  0.904...........................              16  2.99.
                                   baghouse, improved
                                   primary and
                                   secondary hooding,
                                   tertiary hooding.
Flash furnace fugitives.........  Matte tapping                 0.495  0.1025..........................            79.3  1.03.
                                   ventilation system.
Converter aisle fugitives.......  Secondary hood                0.968  0.024...........................            97.5  0.37.
                                   baghouse, improved
                                   primary and
                                   secondary hooding,
                                   tertiary hooding.
Anode furnace fugitives.........  Improved                      0.417  0.04............................            89.7  0.04.
                                   ventilation system.
Anode baghouse stack............  Sent to the main             0.0113  Included in main stack..........             N/A  Included in main stack.
                                   stack.
Slag dump.......................  Restrictions on                0.05  0.05............................  ..............  0.05.
                                   slag dumping
                                   location.
Gas cleaning waste material.....  Thickener project..            0.26  0.07............................              73  0.07.
Concentrate storage area........  Wind fence, water             0.001  0.000056........................              94  0.00088.
                                   sprays.
Bedding area....................  Wind fence, water           0.00017  0.000015........................              91  0.00016.
                                   sprays.
Reverts operations..............  Wind fence, water            0.0122  0.00042.........................              97  0.0041.
                                   sprays.
Paved roads.....................  Sweepers...........           0.091  0.015 \b\.......................              84  0.015.
Unpaved roads...................  Chemical dust                 0.046  0.028 \b\.......................              39  0.028.
                                   suppressant (on a
                                   schedule achieving
                                   90% control
                                   efficiency).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ PTE values for the concentrate storage area, bedding area, and reverts operations were derived using the same calculation methods that were applied
  to calculate 2019 projected actuals. However, for PTE values, Asarco supplied more conservative throughput. Also, the lead factors used for PTE
  calculations were based on mean lead assay values (source specific) plus two standard deviations.
\b\ Projected actual values for paved and unpaved roads were based on PTE.
Source: ADEQ Modeling TSD, Table 8-1.

4. Proposed Action on the Base Year Emissions Inventory
    We have reviewed the emissions inventory and calculation 
methodology used by ADEQ in the 2017 Hayden Lead Plan for consistency 
with CAA requirements, the lead NAAQS rule, and the EPA's guidance. We 
find that the 2012 base year inventory is a comprehensive, accurate, 
and current inventory of actual emissions of lead in the Hayden Lead 
NAA. We therefore propose to approve the 2012 base year inventory as 
meeting the requirements of CAA section 172(c)(3). We are not proposing 
action on the projected attainment inventory, since it is not a 
required SIP element. However, we have evaluated it for consistency 
with EPA guidance and find that it supports the attainment and RFP 
demonstrations, as discussed in the TSD and below.

C. Reasonably Available Control Measure/Reasonably Available Control 
Technology Demonstration and Adopted Control Strategy

1. Requirements for RACM/RACT
    CAA section 172(c)(1) requires that each attainment plan provide 
for implementation of RACM (including RACT for existing sources) as 
expeditiously as practicable and provide for attainment of the NAAQS. 
The EPA defines RACM as measures that are both reasonably available and 
contribute to

[[Page 31092]]

attainment as expeditiously as practicable in the nonattainment area. 
Lead nonattainment plans must contain RACM (including RACT) that 
address sources of ambient lead concentrations. The EPA's historic 
definition of RACT is the lowest emissions limitation that a particular 
source is capable of meeting by the application of control technology 
that is reasonably available, considering technological and economic 
feasibility.\22\ The EPA recommends that, at a minimum, all stationary 
sources emitting 0.5 tpy or more of lead should undergo a RACT 
review.\23\ Based on the 2011 national emissions inventory (2011 NEI 
v2) and the 2012 base year emissions inventory, the Asarco copper 
smelter is the only point source in the Hayden Lead NAA that emits over 
0.5 tpy of lead.\24\
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    \22\ See, for example, 44 FR 53761 (September 17, 1979) and 
footnote 3 of that notice.
    \23\ 73 FR 67038.
    \24\ 2017 Hayden Lead Plan, Chapter 3: Emissions Inventories and 
Appendix A: Emission Inventory Technical Support Document for the 
2008 Hayden Lead Nonattainment Area, Chapter 5, Base Year Emission 
Inventory for Lead in the Hayden Planning Area.
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2. RACM/RACT Demonstration in the 2017 Hayden Lead Plan
    Because of lead's dispersion characteristics, the highest ambient 
concentrations of lead are expected to be near lead sources, such as 
the Hayden Facility. This RACM/RACT analysis focuses on evaluating 
controls at the Hayden Facility, and unlike in a typical RACM 
demonstration for other types of pollutants, we are not evaluating the 
broader set of source categories in the Hayden Lead NAA. This is an 
appropriate approach in this case because the Hayden Facility is the 
source of over 99 percent of lead emissions in the Hayden Lead NAA.\25\
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    \25\ 2017 Hayden Lead Plan, page 38.
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    ADEQ's control strategy relies on the implementation of two source-
specific regulations in the Arizona Administrative Code: Rule R18-2-
B1301 (Limits on Lead Emissions from the Hayden Smelter) and Rule R18-
2-B1301.01 (Limits on Lead-Bearing Fugitive Dust from the Hayden 
Smelter), and two associated appendices. ADEQ submitted these rules to 
the EPA for SIP approval on April 6, 2017.\26\ We approved Rule R18-2-
B1301.01 and Appendix 15 into the Arizona SIP on February 22, 2018,\27\ 
and proposed to approve Rule R18-2-B1301 and Appendix 14 on March 30, 
2018.\28\ The controls required under these rules are also required 
under a 2015 consent decree between Asarco and the United States.\29\
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    \26\ See letter dated April 6, 2017, from Timothy S. Franquist, 
Director, Air Quality Division, ADEQ, to Alexis Strauss, Acting 
Regional Administrator, EPA Region IX.
    \27\ 83 FR 7614.
    \28\ 83 FR 13716.
    \29\ Consent Decree No. CV-15-02206-PHX-DLR (D. Ariz).
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    ADEQ's RACM/RACT analysis can be found on pages 60 through 121 of 
the 2017 Hayden Lead Plan. The EPA's Lead RACM Guidance did not provide 
specific guidance on what constituted RACM/RACT for primary copper 
smelters. Consistent with that guidance, ADEQ looked to other federal 
requirements for lead control at primary copper smelters, similar 
source categories for which the EPA had established lead control 
guidance, and other regulations that the EPA has approved as RACM/RACT 
for lead control. ADEQ used the following references for comparison of 
lead controls: The national emissions standard for hazardous air 
pollutants (NESHAP) requirements for primary copper smelters at 40 CFR 
63, subpart QQQ and the NESHAP requirements for secondary lead smelters 
at 40 CFR 63, subpart X. For fugitive lead-bearing dust control, ADEQ 
also used the following references for comparison: Appendix 1 of the 
General Preamble for Implementation of Title I of the Clean Air 
Act,\30\ which describes control measures for fugitive lead-bearing 
dust; South Coast Air Quality Management District (SCAQMD) Rule 1420.1 
for lead battery recycling facilities (``Emissions Standards for Lead 
and Other Toxic Air Contaminants from Large Lead-Acid Battery Recycling 
Facilities''); and particulate matter (PM) fugitive dust rules enacted 
by other states and local agencies.
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    \30\ 58 FR 67748 (December 22, 1993).
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    The EPA's TSDs on Rules R18-2-B1301 and R18-2-B1301.01 and 
Appendices 14 and 15 contain our detailed analysis on the 
enforceability, stringency, and SIP revision implications for the 
measures contained in these rules.\31\ We evaluate below whether these 
measures satisfy the statutory requirements for RACM/RACT for the 
Hayden Lead NAA.
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    \31\ See Technical Support Document for the EPA's Rulemaking for 
the Arizona State Implementation Plan: Arizona Department of 
Environmental Quality Rule R18-2-B1301.01, Limits on Lead-Bearing 
Fugitive Dust from the Hayden Smelter, and Appendix 15, Test Methods 
for Determining Opacity and Stabilization of Unpaved Roads (August 
2017); Technical Support Document for the EPA's Rulemaking for the 
Arizona State Implementation Plan: Arizona Administrative Code Title 
18, Chapter 2 Appendix 14 and Rule R18-2-715.02 (March 2018); and 
Technical Support Document for the EPA's Rulemaking for the Arizona 
State Implementation Plan: Arizona Administrative Code Title 18, 
Chapter 2, Article 13 Part B--Hayden, Arizona, Planning Area R18-2-
B1301--Limits on Lead Emissions from the Hayden Smelter (March 
2018).
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a. Rule R18-2-B1301 and Appendix 14
    Rule R18-2-B1301 establishes a lead emission limit for the Hayden 
Facility's main stack and operations and maintenance (O&M) 
requirements, including the development of an O&M plan for the capture 
and control system, monitoring provisions for parametric limits 
required to ensure sufficient capture of fugitive lead emissions from 
the smelter, performance testing requirements, compliance determination 
requirements, recordkeeping requirements, and reporting requirements. 
Rule R18-2-B1301 also requires the completion of a fugitive emissions 
study to characterize lead emissions from the smelter structure that 
may contribute to nonattainment, but are not captured or controlled. 
Appendix 14 establishes specific requirements for the study, which is 
required to validate both the estimate of fugitive emissions used in 
the attainment demonstration and the operating conditions or ranges for 
the capture devices' O&M plan.
    Rule R18-2-B1301 establishes a lead emission limit from the 
smelter's stack of 0.683 pounds of lead per hour. Fugitive lead 
emissions from the smelter structure are constrained through an 
improved fugitive gas capture system over the furnace taps and 
converter chambers. In lieu of a fugitive emissions limit, Asarco must 
operate its gas capture system within certain operating parameters as 
described in the facility's O&M plan. Rule R18-2-B1301 defines critical 
parameters and specifies operating limits on those parameters that the 
O&M plan must require, at a minimum, in order to sufficiently control 
fugitive emissions. The fugitive emissions rate will be validated 
through a year-long fugitive emission study as described in Appendix 
14, and it must not exceed the modeled attainment emission rate. If 
actual fugitive emissions exceed the modeled emission rates shown in 
Table 5 above and Asarco is unable to demonstrate attainment of the 
NAAQS at the actual measured fugitive emissions levels, ADEQ will need 
to revise the O&M plan parametric limit minimums as required in R18-2-
B1301 and, as necessary, require additional controls to further reduce 
fugitive emissions. ADEQ must submit these changes as revisions to the 
Arizona SIP. Other requirements include monitoring, recordkeeping, and 
reporting provisions to ensure compliance with the emission and 
parametric limits.

[[Page 31093]]

    We compared these requirements with the primary copper smelter 
NESHAP and the secondary lead smelter NESHAP in the TSD we prepared in 
support of our rulemaking action on R18-2-B1301, and we found the rule 
requirements to be generally consistent with those in the NESHAP. For 
example, the primary copper smelter NESHAP requires a capture system 
and control device O&M plan and requires that the smelter operate 
consistently with good air pollution control practices, similar to R18-
2-B1301. The requirements of R18-2-B1301 are also similar to the 
secondary lead smelter NESHAP requirements, except that the NESHAP 
includes emissions limits of 1.0 milligrams of lead per dry standard 
cubic meter for any process vent gas and 0.20 milligrams of lead per 
dry cubic meter on a rolling 12-month average basis. We propose to find 
that these limits are not required as RACM for the Hayden Facility 
because they are intended for a different type of facility and, as 
discussed below, ADEQ's air quality modeling indicates that the main 
stack emission limit in R18-2-B1301 (0.683 pound of lead per hour) is 
sufficient for the Hayden area to attain the lead NAAQS.
b. Rule R18-2-B1301.01 and Appendix 15
    Rule R18-2-B1301.01 establishes work practice requirements and 
control measures on sources of lead-bearing fugitive dust surrounding 
the Hayden Facility. Appendix 15 applies to unpaved roads at the Hayden 
Facility and includes the following: (1) A test method for determining 
opacity for fugitive dust from these rules, (2) a test method for 
determining silt content of the trafficked parts of unpaved roads, and 
(3) a Qualification and Testing section containing certification 
requirements and procedures, specifications, and calibration 
procedures.
    Rule R18-2-B1301.01 specifies a range of operational standards and 
work practices for processes that may cause emissions of lead-bearing 
fugitive dust. The requirements must be detailed in a fugitive dust 
plan that at minimum includes the performance and housekeeping 
requirements. Subsection (D) includes the following minimum performance 
and housekeeping requirements, which must be met independent of the 
fugitive dust plan:
     Procedures for high wind events, including wetting of 
sources and cessation of operations if necessary;
     Physical inspection requirements of control equipment and 
dust-generating processes to ensure proper operation;
     Opacity limit of 20 percent and requirements to take 
corrective action if opacity exceeds 15 percent;
     Requirements for paved road cleaning at least daily, with 
vehicular track-out controls and 15 mile per hour speed limits;
     Requirements for the application frequency of chemical 
dust suppressant to unpaved roads, controls on silt loading on those 
roads (silt loading may not exceed 0.33 ounces per square feet or 6 
percent), runoff collection requirements to prevent dust from becoming 
airborne, and 15 miles per hour speed limits;
     Materials storage, handling, and unloading requirements 
for copper concentrate and reverts, including requirements for storage 
on concrete pads, water sprayers, and wind fences;
     Bedding requirements (including loading and unloading 
operations requirements for wind fences and water spraying to maintain 
a nominal 10 percent surface moisture content), rumble grates to reduce 
trackout at exits, and a daily cleaning schedule inside and near the 
protected area; and
     Requirements for the acid plant scrubber blowdown drying 
system, which must be housed in an enclosed system that uses a venturi 
scrubber, thickener, filter press and electric dryer under negative 
pressure.
    Subsection (E) of Rule R18-2-B1301.01 includes contingency 
requirements for increasing the frequency of road cleaning if the 
Hayden area does not attain the NAAQS by the attainment date or make 
RFP. The remainder of the rule includes monitoring, compliance 
demonstration, recordkeeping, and reporting requirements. Appendix 15 
includes test methods and procedures for determining compliance with 
opacity limits on unpaved roads, silt content on trafficked parts of 
unpaved roads, and a qualification and testing section for certifying 
observers in measuring opacity and road stabilization. These 
requirements address the known sources of fugitive dust resulting from 
operations surrounding the Hayden Facility that may contribute to 
airborne lead emissions. We compared these requirements in our TSD 
reviewing Rule R18-2-B1301.01 with the primary copper smelter NESHAP 
and SCAQMD Rule 1420.1 for lead control. Rule R18-2-B1301.01 is more 
stringent than the primary copper smelter NESHAP. For example, Rule 
R18-2-B1301.01 includes specific fugitive dust requirements and a 20 
percent opacity limit for lead-bearing fugitive dust, whereas the 
NESHAP contains more general requirements for a fugitive dust plan and 
no opacity limit for fugitive dust. We concluded that while the SCAQMD 
rule was more stringent in some respects (i.e., requiring total 
enclosure of the facility, lower speed limits, more frequent sweeping 
schedules), it was also intended for a different type of facility (lead 
battery recycling) and therefore was not directly comparable to the 
Hayden Facility.
    We also compared these requirements to those found in various RACM/
RACT particulate matter (PM) rules, as the controls for lead-bearing 
fugitive dust in a context like the Hayden Facility are like those for 
controlling PM. We found that Rule R18-2-B1301.01 was as stringent or 
more stringent than those PM rules. For example, in addition to a 20 
percent opacity limit and requirements for chemical dust suppressant 
and soil stabilization, which are also included in the PM rules, Rule 
R18-2-B1301.01 has requirements for unpaved roads and corrective 
measures for visible emissions that are not found in the PM rules.
3. Proposed Actions on RACM/RACT Demonstration and Adopted Control 
Strategy
    For the reasons described above, we find that the control measures 
required under Rules R18-2-B1301 and R18-2-B1301.01 and reflected in 
the 2017 Hayden Lead Plan are reasonably available for the Hayden 
Facility. In addition, as explained in the following section, ADEQ's 
air quality modeling indicates these measures are sufficient to provide 
for attainment in the Hayden Lead NAA. These measures are required to 
be implemented by July 1, 2018 (for Rule R18-2-B1301) and December 1, 
2018 (for Rule R18-2-B1301.01). We believe these are the most 
expeditious dates practicable, given the history of planning for this 
source, the current time frame for implementation, and the complexity 
of these control measures. Accordingly, we propose to find that the 
RACM/RACT measures are both reasonably available and provide for 
attainment as expeditiously as practicable in the Hayden Lead NAA. 
Therefore, we propose to find that the 2017 Hayden Lead Plan provides 
for the implementation of RACM/RACT as required by CAA section 
172(c)(1).

D. Attainment Demonstration

1. Requirements for Attainment Demonstration
    CAA section 172 requires a state to submit a plan for each of its

[[Page 31094]]

nonattainment areas that demonstrates attainment of the applicable 
ambient air quality standard as expeditiously as practicable but no 
later than the specified attainment date. This demonstration should 
consist of four parts:
    (1) Technical analyses that locate, identify, and quantify sources 
of emissions that are contributing to violations of the lead NAAQS;
    (2) Analyses of future year emissions reductions and air quality 
improvement resulting from already-adopted national, state, and local 
programs and from potential new state and local measures required to 
meet the RACT, RACM, and RFP requirements in the area;
    (3) Additional emissions reduction measures with schedules for 
implementation; and
    (4) Contingency measures required under section 172(c)(9) of the 
CAA.
    The requirements for the first three parts are described in the 
sections on emissions inventories and RACM/RACT above and in the 
sections on air quality modeling and the attainment demonstration that 
follow immediately below. The requirements for the fourth part are 
described below in section IV.F.
2. Air Quality Modeling in the 2017 Hayden Lead Plan
    In the following discussion we evaluate various features of the 
modeling that ADEQ used in its attainment demonstration. The lead 
attainment demonstration must include air quality dispersion modeling 
developed in accordance with EPA's Guideline on Air Quality Models, 40 
CFR part 51, appendix W (``Appendix W'').\32\ A more detailed 
description of the modeling used to support this action and our review 
can be found in the 2017 Hayden Lead Plan, Appendix B, Modeling 
Technical Support Document: Hayden Pb State Implementation Plan 
Revision (``ADEQ Modeling TSD'') and our TSD for today's proposed 
action.
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    \32\ The EPA published revisions to Appendix Wat 82 FR 5182 
(January 17, 2017).
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a. Model Selection
    In 2005, the EPA promulgated AERMOD as the Agency's preferred near-
field dispersion model for a wide range of regulatory applications 
addressing stationary sources (e.g., for estimating lead 
concentrations) in all types of terrain, based on extensive 
developmental and performance evaluation. The State used AERMOD version 
15181 to model all emission sources using regulatory default 
options.\33\ After submitting the Plan, ADEQ discovered an error in the 
processing of the Camera Hill meteorological data. In May 2018, ADEQ 
submitted revised modeling using corrected Camera Hill meteorological 
data and AERMOD version 16216r,\34\ which the EPA designated as the 
regulatory version of AERMOD in January 2017.\35\ All other inputs 
remained the same. The remainder of this section refers to results of 
the revised modeling, which effectively supersedes the modeling 
originally submitted with the Plan.
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    \33\ The EPA periodically releases updated versions of AERMOD. 
At the time the State conducted its modeling, version 15181, the 
then-current regulatory version, was released with several beta 
options. The regulatory default for version 15181 is the use of 
version 15181, as released by the EPA, without the use of any of the 
beta options. See https://www.epa.gov/scram/air-quality-dispersion-modeling-preferred-and-recommended-models.
    \34\ See email from Farah Mohammadesmaeili, ADEQ to Rynda Kay, 
EPA, Region 9, dated May 22, 2018.
    \35\ See 82 FR 5182, 5189 (January 17, 2017).
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    The modeling domain was centered on the Hayden Facility and 
extended to the edges of the Hayden Lead NAA. A grid spacing of 25 
meters was used to resolve AERMOD model concentrations along the 
ambient air boundary surrounding the Hayden Facility and was increased 
toward the edges of the NAA. Receptors were excluded within the ambient 
air boundary, which is generally defined by the facility's physical 
fence line, except in certain areas where the State inspected the 
terrain and concluded steep topography precludes public access.\36\ We 
conclude that the model receptors placed by the State adequately 
characterize ambient air conditions.
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    \36\ Ambient air is considered to be the air in those areas 
where the public generally has access. Non-ambient air generally 
includes property owned or controlled by the source to which access 
by the public is prohibited by a fence or other effective physical 
barrier.
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b. Meteorological Data
    ADEQ conducted its modeling using meteorological data collected 
between August 2013 and August 2014 at two on-site surface 
meteorological stations: The Camera Hill site located approximately 
0.35 kilometer (km) south of the smelter building, and the Hayden Old 
Jail site located approximately 1.06 km west of the concentrator and 
smelter complexes at the Hayden Facility. Due to the complex topography 
of the area, wind speed and direction can vary significantly between 
the two stations. The State conducted a performance evaluation to test 
which meteorological dataset performs best when AERMOD-predicted 
concentrations are compared to monitored concentrations.\37\ The State 
concluded emissions from the main stack and those emanating from the 
smelter building roofline are best represented by Camera Hill, while 
lower elevation sources were best represented by Hayden Old Jail, and 
used these respective data sets for those sources. Accordingly, ADEQ 
ran the model separately for each set of sources and summed the results 
appropriately. The State provided audit reports for each monitoring 
station to document the station's installation and data collection 
procedures.\38\ The State used AERMET version 16216 to process 
meteorological data for use with AERMOD.
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    \37\ See email from Farah Mohammadesmaeili, ADEQ, to Rynda Kay, 
EPA Region 9, dated May 25, 2018.
    \38\ See email from Farah Mohammadesmaeili, ADEQ, to Rynda Kay, 
EPA Region 9, dated May 22, 2018.
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    The State used AERSURFACE version 13016 using data from the Camera 
Hill and Hayden Old Jail sites to estimate the surface characteristics 
(i.e., albedo, Bowen ratio, and surface roughness (zo)). The 
State estimated zo values for 12 spatial sectors out to 1 km 
at a seasonal temporal resolution for average conditions. We conclude 
that the State appropriately selected meteorological sites, properly 
processed meteorological data, and adequately estimated surface 
characteristics.
    ADEQ used the Auer (1978) \39\ land use method, with land cover 
data from the United States Geological Survey National Land Cover Data 
1992 archives, to determine that the 3-km area around the Hayden 
Facility is composed of 96.2 percent rural land types. Therefore, the 
State selected rural dispersion coefficients for modeling. We agree 
with the ADEQ's determination that the facility should be modeled as a 
rural source.
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    \39\ See Auer, A.H., 1978. Correlation of Land Use and Cover 
with Meteorological Anomalies. Journal of Applied Meteorology, 
17(5):636-643.
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c. Emissions Data
    ADEQ developed a modeling emissions inventory based on 2012 data 
for sources within the Hayden Lead NAA and for the 50-km buffer zone 
extending from the NAA boundary. In 2012, the Hayden Facility emitted 
3.43 tpy lead, accounting for more than 99 percent of lead emissions in 
the Hayden Lead NAA. The Freeport McMoRan Incorporated copper smelter, 
located 46 km north of the Hayden Facility, emitted 4.87 tons of lead 
in 2012; however, the two smelters are separated by large mountains, 
making these two airsheds distinct. The State determined that aside 
from the Hayden facility, no

[[Page 31095]]

other sources were drivers of nonattainment or have the potential to 
cause significant concentration gradients in the vicinity of the Hayden 
Lead NAA. We agree with the State's determination that only Hayden 
Facility emissions need to be included in the attainment modeling.
    Asarco is undertaking substantial upgrades to the Facility that 
will reduce lead and other pollutant emissions (see section IV.C, 
above). The State modeled post-upgrade lead emissions based on an 
emission limit of 0.67 lb/hour for the main stack and emission 
estimates for fugitive emission sources based on control requirements 
in Rules R18-2-B1301 and R18-2-B1301.01. These rules address roofline 
vents over the anode furnace, converter aisle, and the flash furnace; 
outdoor slag pouring; materials storage and handling (bedding area, 
revert piles, concentrate storage), paved and unpaved roads, crushing 
and screening, and a gas cleaning plant. The State provided details and 
supporting information for the control efficiencies assumed in 
developing model emission rates. This information, which we reviewed 
and agree is reasonable, is contained in multiple appendices \40\ and 
supporting spreadsheets \41\ that were submitted with the Plan.
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    \40\ See Plan Appendix B (ADEQ Modeling TSD), Section 5, and 
Appendix A (ADEQ Emission Inventory TSD), Section 7.
    \41\ Detailed information on 2019 projected emission estimates 
is contained in spreadsheet ``2012 Actuals & 2019 
projections.xlsx,'' while supporting information for the maximum 
allowable PTE estimates is contained in ``Facility PTE.xlsm.''
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    The State adequately characterized source parameters (as described 
in detail in our TSD) as well as the Facility's building layout and 
locations in its modeling. Where appropriate, the Building Profile 
Input Program for PRIME, which is a component of AERMOD, was used to 
assist in characterizing building downwash.
d. Background Concentrations
    ADEQ selected background lead concentrations using ambient air 
measurements recorded in 2013 at Children's Park monitor in Tucson, 
Arizona (AQS ID: 04-019-1028), a regionally representative site. This 
monitor began measuring 24-hour mean concentrations of lead in total 
suspended particulate in February 2012 and operated through May 2016. 
The State used all available measurements during 2013 and calculated a 
mean concentration of 0.0028 [mu]g/m\3\. The State used this as the 
background concentration, and added it to the modeled design 
values.\42\ The State determined that it was more appropriate to base a 
background concentration on data from this site as opposed to using 
monitoring data near the Hayden Facility during smelter shut-down 
periods. During shut-downs an increased amount of material handling 
occurs throughout the facility, elevating the observed concentrations. 
We agree that ADEQ appropriately and conservatively calculated 
background concentrations.
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    \42\ Data from 2013 were used because two months of data were 
missing in the 2012 base year.
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e. Summary of Results
    The EPA has reviewed ADEQ's attainment demonstration for the Hayden 
Lead NAA and is proposing to determine that the supporting modeling is 
consistent with CAA requirements and Appendix W. The State's modeling 
indicates that if the Facility were to emit at maximum allowed levels, 
the maximum 3-month average ambient concentration would be 0.14165 
[mu]g/m\3\, which is below the NAAQS level of 0.15 [mu]g/m\3\.\43\ \44\ 
This modeled concentration includes the background lead concentration 
of 0.0028 [micro]g/m\3\. The modeling indicates that the controls 
required under Rules R18-2-B1301 and R18-2-B1301.01 are sufficient for 
the Hayden Lead NAA to attain the 2008 lead NAAQS.
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    \43\ See ``Hayden-Pb-Modeling Notes-05142018'' (attached to 
email from Farah Mohammadesmaeili, ADEQ, to Rynda Kay, EPA Region 9, 
dated May 22, 2018), and Memo to Rulemaking Docket EPA-R09-OAR-2018-
0222 titled ``Revised Attainment Demonstration and Contingency 
Measure Modeling--LEADPOST Output Files,'' from Rynda Kay, EPA 
Region 9, dated June 12, 2018.
    \44\ As illustrated in Table 5 of today's action, actual 
emissions are expected to be well below allowable levels.
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E. Reasonable Further Progress Demonstration

1. Requirements for RFP
    CAA section 172(c)(2) requires that attainment plans shall provide 
for RFP. RFP is defined in section 171(1) as such annual incremental 
reductions in emissions of the relevant air pollutant as are required 
by CAA title I, part D for nonattainment areas or may reasonably be 
required by the Administrator for the purpose of ensuring attainment of 
the applicable NAAQS by the applicable date. Historically, RFP has been 
met through generally linear incremental progress toward attainment by 
the applicable attainment date. However, the EPA believes that RFP for 
lead nonattainment areas should be met by ``adherence to an ambitious 
compliance schedule,'' which is expected to periodically yield 
significant emission reductions, and as appropriate, linear 
progress.\45\
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    \45\ 73 FR 66964 at 67038.
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    The EPA recommends that SIPs for lead nonattainment areas provide a 
detailed schedule for compliance with RACM (including RACT) in the 
affected areas and accurately indicate the corresponding annual 
emission reductions to be achieved,\46\ and expects that a detailed 
schedule would provide for periodic yields in significant emissions 
reductions.\47\ We believe that it is appropriate to expect early 
implementation of less technology-intensive control measures (e.g., 
controlling fugitive dust emissions at the stationary source, as well 
as required controls on area sources) while phasing in the more 
technology-intensive control measures, such as those involving the 
purchase and installation of new hardware. The expeditious 
implementation of RACM/RACT at affected sources within the 
nonattainment area is an appropriate approach to assure attainment of 
the lead NAAQS in an expeditious manner.\48\
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    \46\ Id., at 67039; Lead Q&A, p. 2.
    \47\ Id.
    \48\ See 73 FR 66964 (November 12, 2008) at 67038-67039.
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2. RFP Demonstration in the 2017 Hayden Lead Plan
    The RFP demonstration for the Hayden area is located in Chapter 4 
of the 2017 Hayden Lead Plan. The Plan includes a detailed schedule for 
the expeditious implementation of key controls required under Rules 
R18-2-B1301 and R18-2-B1301.01, along with the emissions reductions 
associated with these controls, as shown in Table 6.\49\ Failure to 
implement any of these control measures by the associated deadline 
would constitute a failure to make RFP and thus trigger implementation 
of contingency measures, as described in section IV.F below.
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    \49\ The Plan bases certain implementation dates on the date of 
EPA's approval of Asarco's fugitive dust plan under Consent Decree 
No. CV-15-02206-PHX-DLR (D. Ariz). See Plan Table 23. The EPA 
approved the wind fence elements of the fugitive dust plan on June 
26, 2017 and December 20, 2017. See Letters from Matt Salazar, EPA 
Region 9, to Joseph Wilhelm, Asarco, dated June 26, 2017 and 
December 20, 2017. The remaining elements were approved on March 15, 
2018. See Letter from Matt Salazar, EPA Region 9, to Joseph Wilhelm, 
Asarco, dated March 15, 2018. The implementation dates in Table 6 
are calculated accordingly.

[[Page 31096]]

    Table 6--Control Implementation Schedule and Emission Reductions
------------------------------------------------------------------------
                                                           Pb emissions
          Control measure                  Date of          reduced per
                                       implementation       year (tpy)
------------------------------------------------------------------------
Implementation of chemical dust     April 14, 2018......         0.018
 suppression for unpaved roads.
Implementation of wind fences for   October 24, 2017 and         0.00488
 materials piles (uncrushed          April 18, 2018.
 reverts, reverts crushing and
 crushed reverts, bedding
 materials, and concentrate).
Implementation of water sprays for  July 13, 2018.......
 materials piles (uncrushed
 reverts, reverts crushing and
 crushed reverts, bedding
 materials, and concentrate).
Implementation of new acid plant    November 30, 2016...         0.190
 scrubber blowdown drying system.
Implementation of new primary,      July 1, 2018........         1.318
 secondary, and tertiary hooding
 systems for converter aisle.
Implementation of new ventilation   July 1, 2018........         0.393
 system for matte tapping and slag
 skimming for flash furnace.
------------------------------------------------------------------------
Source: Plan, Table 23.

    For informational purposes, Figures 7 and 8 in the Plan also depict 
past and projected changes to ambient concentrations of lead. These 
figures demonstrate that implementation of the controls required under 
the Plan will bring the ambient concentration in the Hayden Lead NAA 
into compliance with the lead NAAQS. The ambient concentration 
projections also support the State's contingency measure analysis, as 
discussed below.
3. Proposed Action on the RFP Demonstration
    Consistent with EPA guidance, the Hayden lead SIP provides a 
detailed schedule for implementing required controls and accurately 
indicates the corresponding annual emission reductions to be 
achieved.\50\ These reductions will occur at sources, such as unpaved 
roads and various non-smelting fugitive sources that have a greater 
influence on the maximum predicted ambient impacts than the smelter 
point sources and the schedule provides for periodic yields in 
significant emissions reductions sufficient to attain the NAAQS. We 
therefore propose to find that the 2017 Hayden Lead Plan meets the 
requirements of section 172(c)(2) for RFP.
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    \50\ See Table 6.
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F. Contingency Measures

1. Requirements for Contingency Measures
    Under CAA section 172(c)(9), all lead attainment plans must include 
contingency measures to be implemented if an area fails to meet RFP or 
fails to attain the lead NAAQS by the applicable attainment date. These 
contingency measures must be fully adopted rules or control measures 
that are ready to be implemented quickly and without significant 
additional action by the state or the EPA if the area fails to meet RFP 
requirements or fails to meet its attainment date. They must also be 
measures not relied on to demonstrate RFP or attainment in the plan and 
should provide SIP-creditable emissions reductions generally equivalent 
to about one year's worth of RFP. The EPA has explained that, ``where a 
single source is responsible for nonattainment, it may be possible to 
identify the amount of reductions required by reference to reductions 
in ambient air concentrations.'' \51\ Finally, the SIP should contain a 
trigger mechanism for the contingency measures and specify a schedule 
for their implementation.\52\
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    \51\ See Lead Q&A, p.3.
    \52\ See CAA section 172(c)(9).
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    The EPA recognizes that certain actions, such as the notification 
of sources, modification of permits, etc., may be needed before a 
measure can be implemented. However, states must show that their 
contingency measures can be implemented with only minimal further 
action on their part and with no additional rulemaking actions such as 
public hearings or legislative review. The EPA generally expects all 
actions needed to affect full implementation of the contingency 
measures to occur within 60 days after the EPA notifies the state of 
such failure.\53\ The state should therefore ensure that the measures 
are fully implemented as expeditiously as practicable after the 
requirement takes effect.
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    \53\ 73 FR 66964 at 67039.
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2. Contingency Measure in the 2017 Hayden Lead Plan
    Chapter 4 of the 2017 Hayden Lead Plan describes the contingency 
measure that will be implemented if the area fails to meet RFP or fails 
to attain by its attainment date. The contingency measure and the 
associated calculations are summarized below.
    Because lead concentrations in the Hayden area are almost entirely 
attributable to the Asarco smelter, ADEQ chose to use ambient air 
concentrations to demonstrate equivalency to a year's worth of RFP. To 
determine the amount of emissions reductions needed for contingency 
measures (annual average RFP) ADEQ used the following equation:

(2012 highest monitored concentration--2019 modeled concentration)/7 
years = Annual Average RFP

    Using this equation, ADEQ initially calculated it would need a 
contingency measure that would achieve a reduction in ambient lead 
concentrations of at least 0.0114 [mu]g/m\3\.\54\ Based on the revised 
modeling submitted by ADEQ in May 2018, the contingency measure would 
need to achieve a reduction of at least 0.0086 [mu]g/m\3\.\55\
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    \54\ 0.20 [mu]g/m\3\-0.12 [mu]g/m\3\/7 years = 0.0114 [mu]g/
m\3\.
    \55\ See Memo to Rulemaking Docket EPA-R09-OAR-2018-0222 titled 
``Revised Attainment Demonstration and Contingency Measure 
Modeling--LEADPOST Output Files,'' from Rynda Kay, EPA Region 9, 
dated June 12, 2018.
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    ADEQ Rule R18-2-B1301.01 requires that Asarco increase the 
frequency of paved road cleaning from once per day to twice per day 
within 60 days of notification by the EPA that the area has failed to 
make RFP or to attain by the statutory attainment date.\56\ To 
determine the benefit of the increased road cleaning frequency, ADEQ 
applied a 45 percent reduction to the paved road silt content 
percentage that Asarco reported in its 2015 emissions inventory (which 
reflected once-daily street sweeping).\57\ The State determined that

[[Page 31097]]

the implementation of this measure would reduce the modeled design 
value from 0.14165 [mu]g/m\3\ to 0.12935 [mu]g/m\3\.\58\ This amounts 
to a reduction of 0.0123 [mu]g/m\3\, which exceeds the amount of 
reductions required from contingency measures (one year's RFP).
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    \56\ The EPA approved this rule on February 22, 2018 (83 FR 
7614).
    \57\ To cross check the emissions inventory, ADEQ back-
calculated the silt content percentage on paved roads to determine 
if it was consistent with emissions factors in AP-42. ADEQ assumed 
the 9.5 percent silt content was the result of a 45 percent 
reduction due to once daily street sweeping. The 45 percent figure 
is consistent with the Maricopa Association of Governments' Five 
Percent Plan for PM10, which used a 55 percent reduction, 
but adds in a 10 percent safety margin. The EPA approved the Five 
Percent Plan on June 10, 2014 (79 FR 33107). Using this assumption, 
ADEQ calculated the silt content percentage on paved roads without 
once-daily street sweeping to be approximately 21 percent, which is 
in line with the range of values in AP-42 (15.4-21.7 percent).
    \58\ See ``Hayden-Pb-Modeling Notes-05142018'' (attached to 
email from Farah Mohammadesmaeili, ADEQ, to Rynda Kay, EPA Region 9, 
dated May 22, 2018), Section 4.7.3 and Appendix E of the Plan, and 
Memo to Rulemaking Docket EPA-R09-OAR-2018-0222 titled ``Revised 
Attainment Demonstration and Contingency Measure Modeling--LEADPOST 
Output Files,'' from Rynda Kay, EPA Region 9, dated June 12, 2018.
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3. Proposed Action on the Contingency Measures
    Rule R18-2-B1301.01, which includes a schedule for prompt 
implementation of the contingency measure, is fully adopted by the 
State and has been approved by the EPA. The reductions generated by the 
contingency measure exceed one year's RFP. We therefore propose to find 
that the State has demonstrated that the 2017 Hayden Lead Plan meets 
the requirements of section 172(c)(9) for contingency measures that 
would be triggered for failure to make RFP and/or for failure to 
attain.

G. New Source Review

1. Requirements for NSR
    States containing areas designated as nonattainment for the lead 
NAAQS must submit SIPs that address the requirements of nonattainment 
NSR. Specifically, CAA section 172(c)(5) requires states that have 
areas designated as nonattainment for the lead NAAQS to submit 
provisions requiring permits for the construction and operation of new 
or modified stationary sources anywhere in the nonattainment area, in 
accordance with the permit requirements under CAA section 173.
2. NSR in the 2017 Hayden Lead Plan
    The 2017 Hayden Lead Plan explains that in 2012 ADEQ submitted a 
SIP revision to update its NSR program and that the EPA subsequently 
issued a limited approval/limited disapproval of this SIP revision.\59\ 
ADEQ also noted that it had revised its rules to correct the 
deficiencies identified in the limited approval/limited disapproval and 
intended to submit these changes as a SIP revision. ADEQ subsequently 
submitted this revision and, on May 4, 2018, the EPA approved it into 
the SIP.\60\ These two recent SIP revisions ensure that ADEQ's rules 
provide for appropriate NSR for lead sources undergoing construction or 
major modification in the Hayden Lead NAA. Therefore, the EPA concludes 
that the NSR requirements have been met for this area.
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    \59\ 80 FR 67319 (November 2, 2015).
    \60\ 83 FR 19631 (May 4, 2018).
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3. Proposed Action on NSR
    We propose to find that the State has demonstrated that the Arizona 
SIP meets the requirements of CAA section 172(c)(5) for the Hayden Lead 
NAA.

V. The EPA's Proposed Action and Request for Public Comments

A. The EPA's Proposed Approvals

    This SIP submittal addresses CAA requirements and EPA regulations 
for expeditious attainment of the 2008 lead NAAQS for the Hayden Lead 
NAA. For the reasons discussed above, the EPA is proposing to approve 
under CAA section 110(k)(3) the following elements of the 2017 Hayden 
Lead Plan:
    (1) The SIP's base year emissions inventory as meeting the 
requirements of CAA section 172(c)(3) and 40 CFR 51.117(e)(1);
    (2) the attainment demonstration, including air quality modeling, 
as meeting the requirements of CAA section 172(c)(1);
    (3) the RACM/RACT demonstration as meeting the requirements of CAA 
section 172(c)(1);
    (4) the RFP demonstration as meeting the requirements of CAA 
section 172(c)(2); and
    (5) the contingency measures as meeting the requirements of the CAA 
section 172(c)(9);
    We are also proposing to find that the State has demonstrated that 
the Arizona SIP meets the requirements of CAA section 172(c)(5) for the 
Hayden Lead NAA.

B. Request for Public Comments

    We are taking public comments for thirty days following the 
publication of this proposed rule in the Federal Register. We will take 
all comments into consideration in our final rule.

IV. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the 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 
proposed 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 disproportionate human health or environmental effects with 
practical, appropriate, and legally permissible methods under Executive 
Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where 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

[[Page 31098]]

FR 67249, November 9, 2000). We have offered to consult with the San 
Carlos Apache Tribe, which has lands bordering on the Hayden Lead 
NAA.\61\
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    \61\ See letter from Matthew Lakin, EPA Region 9, to Terry 
Rambler, San Carlos Apache Tribe, dated December 18, 2017.
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List of Subjects in 40 CFR Part 52

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

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

    Dated: June 21, 2018.
Michael Stoker,
Regional Administrator, Region IX.
[FR Doc. 2018-14198 Filed 7-2-18; 8:45 am]
BILLING CODE 6560-50-P