Jared Blumenfeld, Regional Administrator, EPA Region 9 signed the following rule on May 30, 2014, and EPA is 

submitting it for publication in the Federal Register (FR). While we have taken steps to ensure the accuracy of this 

Internet version of the rule, it is not the official version. Please refer to the official version in a forthcoming FR 

publication, which will appear on the Government Printing Office's FDsys website 

(http://fdsys.gpo.gov/fdsys/search/home.action) and on Regulations.gov (http://www.regulations.gov) in Docket 

No. EPA-R09-OAR-2013-0762. 

Billing Code: 6560-50-P

ENVIRONMENTAL PROTECTION AGENCY 

40 CFR Part 52 

[EPA-R09-OAR-2013-0762; FRL-] 

Approval and Promulgation of Implementation Plans – Maricopa 

County PM-10 Nonattainment Area; Five Percent Plan for 

Attainment of the 24-Hour PM-10 Standard 

AGENCY: Environmental Protection Agency (EPA). 

ACTION: Final rule. 

SUMMARY: The Environmental Protection Agency (EPA) is approving 

a State implementation plan (SIP) revision submitted by the 

State of Arizona to meet Clean Air Act (CAA) requirements 

applicable to the Maricopa County (Phoenix) PM-10 Nonattainment 

Area. The Maricopa County PM-10 Nonattainment Area is 

designated as a serious nonattainment area for the national 

ambient air quality standards (NAAQS) for particulate matter of 

ten microns or less (PM-10). The submitted SIP revision 

consists of the Maricopa Association of Governments 2012 Five 

Percent Plan for PM-10 for the Maricopa County Nonattainment 

Area and the 2012 Five Percent Plan for the Pinal County Township 1 

North, Range 8 East Nonattainment Area” (collectively, the 2012 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

2

Five Percent Plan). EPA is approving the 2012 Five Percent Plan 

as meeting all relevant statutory and regulatory requirements. 

DATES: Effective Date: This rule is effective on [INSERT DATE 

30 DAYS FROM DATE OF PUBLICATION IN FEDERAL REGSITER]. 

ADDRESSES: You may inspect the supporting information for this 

action, identified by docket number EPA-R09-OAR-2013-0762, by 

one of the following methods: 

1. Federal eRulemaking portal, http://www.regulations.gov,

please follow the online instructions; or, 

2. Visit our regional office at, U.S. Environmental Protection 

Agency Region IX, 75 Hawthorne Street, San Francisco, CA 94105-

3901. 

Docket: The index to the docket for this action is available 

electronically at http://www.regulations.gov and in hard copy at 

EPA Region IX, 75 Hawthorne Street, San Francisco, California. 

While documents in the docket are listed in the index, some 

information may be publicly available only at the hard copy 

location (e.g., voluminous records, large maps, copyrighted 

material), and some may not be publicly available in either 

location (e.g., Confidential Business Information). To inspect 

the hard copy materials, please schedule an appointment during 

normal business hours with the contact listed directly below. 

FOR FURTHER INFORMATION CONTACT: Doris Lo, EPA Region IX, (415) 

972-3959, lo.doris@epa.gov. 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

3

SUPPLEMENTARY INFORMATION: Throughout this document, “we,” “us” 

and “our” refer to EPA. 

Table of Contents 

I. Summary of Proposed Action 

II. Public Comments and EPA Responses 

III. EPA's Final Action 

IV. Statutory and Executive Order Reviews 

I. Summary of Proposed Action 

On February 6, 2014 (79 FR 7118), EPA proposed to approve 

the 2012 Five Percent Plan,1 which the State of Arizona submitted 

on May 25, 2012, as meeting all relevant statutory and 

regulatory requirements under the Clean Air Act (CAA). As 

discussed in our proposed rule, the Maricopa County (Phoenix) 

PM-10 nonattainment area is a serious PM-10 nonattainment area, 

and is located in the eastern portion of Maricopa County and 

encompasses the cities of Phoenix, Mesa, Scottsdale, Tempe, 

Chandler, Glendale, several other smaller jurisdictions, 

unincorporated County lands, as well as the town of Apache 

Junction in Pinal County. Arizona’s obligation to submit the 

 

1

 The 2012 Five Percent Plan includes the “MAG 2012 Five Percent Plan for PM10 for the Maricopa County Nonattainment Area” (dated May 2012)(MAG 2012 Five 

Percent Plan) and the “2012 Five Percent Plan for the Pinal County Township 1 

North, Range 8 East Nonattainment Area” (dated May 25, 2012)(Pinal 2012 Five 

Percent Plan)(collectively, the 2012 Five Percent Plan). In our proposed 

rule we cited primarily to the MAG 2012 Five Percent Plan; however, both 

plans were submitted by ADEQ on May 25, 2012 and are included in the docket 

for this rulemaking. See May 25, 2012 letters from Henry R. Darwin, 

Director, Arizona Department of Environmental Quality, to Jared Blumenfeld, 

Regional Administrator, U.S. Environmental Protection Agency Region IX. 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

4

2012 Five Percent Plan was triggered by EPA’s June 6, 2007 

finding that the Maricopa PM-10 Nonattainment Area had failed to 

meet its December 31, 2006 deadline to attain the PM-10 NAAQS. 

The CAA requires a serious PM-10 nonattainment area that fails 

to meet its attainment deadline to submit a plan providing for 

attainment of the PM-10 NAAQS and for an annual emission 

reduction in PM-10 or PM-10 precursors of not less than five 

percent until attainment. Our February 6, 2014 proposed rule 

provides the background and rationale for this action.2

II. Public Comments and EPA Responses 

EPA provided a 30-day public comment period on our proposed 

action. The comment period ended on March 10, 2014. We received 

12 public comment letters from State and local agencies, 

industry, congressional representatives and environmental 

groups.3 All of the submitted comment letters are in our docket. 

We respond to all the comments below. 

A. Update 2002 BACM and MSM Determinations 

 

2 We have also approved Arizona statutory provisions and the Dust Action 

General Permit, which were submitted with the 2012 Five Percent Plan. See 

our proposed rule at 79 FR 7118, p. 7123 (footnote 20) and recent EPA actions 

at 79 FR 17878 (March 31, 2014), 79 FR 17879 (March 31, 2014) and 79 FR 17881 

(March 31, 2014). 

3 Commenting organizations include: U.S. Senator Jeff Flake, Arizona Center 

for Law in the Public Interest (2 letters), Maricopa Association of 

Governments, City of Phoenix, Arizona Rock Products Association, Salt River 

Project, ADEQ, Arizona Association of General Contractors, Maricopa County 

Air Quality Department, the Arizona Chamber of Commerce, and Amanda Reeve, 

former Arizona State Representative and Chair of Arizona House Environment 

Committee. 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

5

Comment: The Arizona Center for Law in the Public Interest 

(ACLPI) commented that EPA’s proposed action did not discuss or 

analyze requirements under CAA 189(b)(1)(B) for best available 

control measures (BACM) or requirements under CAA 188(e) for 

most stringent measures (MSM). ACLPI stated that these 

requirements apply to the Maricopa County PM10 nonattainment 

area because it is a serious PM10 nonattainment area that 

obtained a five-year extension of its attainment date pursuant 

to section 188(e) in 2001. ACLPI also asserts that EPA’s 2002 

approval of BACM and MSM requirements must be updated in light 

of EPA’s statements in correspondence to ADEQ and in a proposed 

rulemaking in 2010 that new more stringent control measures have 

been adopted by air agencies in Nevada and California and that 

agricultural controls no longer represent BACM. ACLPI also 

states that addressing the question of whether existing control 

constitute BACM is necessary in order to evaluate ADEQ’s claims 

that 135 exceedances qualify as exceptional events. 

Response: EPA disagrees with the commenter’s statement 

that EPA’s proposed action on the 2012 Five Percent Plan did not 

discuss or analyze section 189(b)(1)(B) and 188(e) requirements 

for BACM and MSM. Our proposed action on the 2012 Five Percent 

Plan explained that the Maricopa County PM-10 nonattainment area 

was initially classified as moderate, and, when it failed to 

reach attainment by the attainment deadline for moderate areas, 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

6

was reclassified, on May 10, 1996, as a serious PM-10 

nonattainment area with a new attainment deadline of December 

31, 2001. See 79 FR 7118-7119. Our proposed action on the 2012 

Five Percent Plan also explained the criteria set forth in 

section 188(e) necessary to grant a five year extension of that 

deadline. In addition, our proposed action on the 2012 Five 

Percent Plan included the following statement: “On July 25, 

2002, EPA approved the serious area PM-10 plan for the Maricopa 

PM-10 Nonattainment Area as meeting the requirements for such 

areas in CAA sections 189(b) and (c), including the requirements 

for implementation of best available control measures (BACM) in 

section 189(b)(1)(B) and MSM in section 188(e). In the same 

action EPA approved the submission with respect to the 

requirements of section 188(d) and granted Arizona’s request to 

extend the attainment date of the area to December 31, 2006.” 4 

79 FR 7119. 

We understand the comment to be more specifically directed 

at the issue of whether our action on the 2012 Five Percent Plan 

requires EPA to “update” or re-evaluate the BACM and MSM 

determinations we made when we acted on the State’s serious area 

plan and attainment deadline extension request in 2002. EPA 

does not agree that the CAA requires such a reevaluation in the 

 

4 EPA’s approval of BACM for this area and approval of the extension under 

section 188(e) were upheld in Vigil v. Leavitt, 366 F.3d 1025, amended at 381 

F.3d 826 (9th Cir. 2004). 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

7

context of acting on a state’s submission of a new plan to meet 

the requirements of section 189(d). We interpret CAA section 

189(b)(1)(B) to provide that the requirement for BACM is 

triggered by a specific event: the reclassification of a 

moderate PM-10 nonattainment area to serious. Similarly, we 

interpret section CAA 188(e) to provide that the requirement for 

MSM is triggered by a particular event: EPA’s granting of a 

state’s request for an extension of the attainment deadline for 

a serious nonattainment area. If a serious nonattainment area 

fails to reach attainment by the applicable deadline, CAA 

section 189(d) requires the state to submit “plan revisions 

which provide for attainment of the PM-10 air quality standard” 

and “for annual reduction in PM-10 . . . of not less than 5 

percent . . . “ The Act, however, does not contain a specific 

requirement that the state update the previously approved 

requirements for BACM and MSM as a consequence of failing to 

reach attainment by the applicable deadline for serious PM-10 

nonattainment areas as an element of the plan revision required 

by section 189(d). 

Consistent with the Act’s structure of requiring 

increasingly stringent obligations as the severity of the air 

pollution problem increases, we interpret sections 189(b)(1)(B) 

and 188(e), as well as 189(d), as parts of a statutory scheme 

that imposes increasingly more stringent requirements when a PM-
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

8

10 nonattainment area fails to reach attainment by applicable 

deadlines. See Addendum to the General Preamble, 59 FR 42010 

(August 16, 1994). As stated previously, the Maricopa County 

PM-10 Nonattainment Area was initially classified as moderate. 

In 1996, when EPA determined that the Area failed to reach 

attainment by the moderate area attainment deadline, EPA 

reclassified the Area to serious. As a consequence of this 

reclassification, the Maricopa County PM-10 Nonattainment Area 

was subject to a new attainment deadline (December 31, 2001) as 

well as new requirements for a serious PM10 attainment plan 

pursuant to CAA section 188(c) and for BACM pursuant to CAA 

section 189(b)(1)(B). Subsequently, the State’s request for an 

extension of the serious area attainment deadline (December 31, 

2006), and EPA’s granting of that request in 2002, resulted in 

an obligation for the State to demonstrate that its SIP imposed 

MSM pursuant to section 188(e). In 2007, EPA’s determination 

that the Maricopa County PM-10 Nonattainment Area had failed to 

reach attainment by the extended serious area deadline resulted 

in section 189(d)’s requirements for plan revisions and annual 

reductions in PM-10 of five percent until attainment. Thus, the 

CAA’s requirements for BACM and MSM are tied to specific 

triggers in the Act: BACM by the reclassification to serious 

following the missed moderate area deadline, and MSM by the 

extension of the serious area deadline. For serious 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

9

nonattainment areas that fail to reach attainment by an 

applicable deadline, the CAA specifies a particular consequence: 

a requirement for additional plan revisions that provide for 

attainment and annual five percent reductions. There is no 

explicit requirement in section 189(d) that a state with a 

serious nonattainment area that misses its attainment deadline 

must also reevaluate BACM and MSM provisions in its SIP that EPA 

has already approved. Indeed, the requirements of section 

189(d) do not specify the requisite level of control and merely 

speak in terms of expeditious attainment and a set percentage of 

annual reductions from the most recent inventory, without regard 

to the level of control on sources needed to achieve those 

objectives. We note further that the commenter did not provide 

a legal rationale to support an interpretation of the Act that 

would require the state to reevaluate the existing BACM and MSM 

in its SIP as part of the explicit requirements of section 

189(d). A state may elect to do so, and may elect to do so as a 

means of achieving additional emissions reductions to meet the 

five percent requirement, but that is not a specific requirement 

of section 189(d). 

EPA notes that it has other discretionary authority under 

the CAA to address deficiencies in existing state SIPs, if that 

were necessary to address substantive concerns like those raised 

by the commenter. If EPA were to find a state SIP to be 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

10

“substantially inadequate” to attain or maintain a standard or 

to meet any other requirements of the CAA, section 110(k)(5) 

provides a remedy by which EPA may require a state to revise its 

SIP to correct the identified inadequacies. In such a 

situation, EPA notifies a state of the inadequacies and can 

allow the state up to 18 months to submit revisions to the SIP 

to address the problems. See 42 U.S.C. 7410(k)(5). EPA has not 

made such a determination with respect to BACM or MSM for the 

Maricopa County PM-10 Nonattainment Area. 

Finally, we note that Arizona was able to demonstrate 

attainment of the PM-10 NAAQS and provide for annual reductions 

of five percent until attainment without requiring additional 

BACM and MSM measures in its SIP.5 Given that this area has 

demonstrated that it attained the PM-10 NAAQS by December 31, 

2012 and has met the requirements of section 189(d), EPA does 

not see a need for the State to reevaluate its existing BACM and 

MSM as part of the action on the 2012 Five Percent Plan. 

We address ACLPI’s comments with respect to BACM and MSM as 

they relate specifically to agricultural controls and 

exceptional events below. 

B. BACM for Agricultural Sources 

 

5 See MAG 2012 Five Percent Plan, at p. 5-7, Table 5-3. Note that the 

emissions from agricultural sources (“tilling, harvesting and cotton ginning” 

and “windblown agriculture”) are constant, reflecting no reductions in 

emissions from 2008 to 2012. 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

11

Comment: ACLPI commented that EPA should not approve the 

2012 Five Percent Plan because it does not include adequate 

measures for agricultural emissions. ACLPI commented that EPA 

has stated that ACC R 18-2-611 [Ag BMP Rule] no longer qualifies 

as BACM because other nonattainment areas have stronger programs 

for controlling agricultural emissions and do not have an 

enforceability issue found in the rule. ACLPI also commented 

that the State’s 2011 revisions to the Ag BMP Rule to address 

concerns identified by EPA are still clearly insufficient to 

qualify as BACM. 

Response: As explained above, CAA section 189(d) does not 

require the State to reevaluate the BACM and MSM determinations 

that were addressed in its serious area PM-10 plan for the 

Maricopa County PM-10 Nonattainment Area. 

In addition, the 2012 Five Percent Plan satisfied all 

requirements for an approvable section 189(d) plan without 

relying on additional emissions reductions from agricultural 

sources. The 2012 Five Percent Plan is based on the “2008 PM-10 

Periodic Emissions Inventory for Maricopa County, Revised 2011 

(2008 Inventory),” which EPA found to be comprehensive, accurate 

and current. 79 FR 7120-7121. The 2008 Inventory shows that 

the most significant sources of emissions in the Maricopa County 

Nonattainment Area are unpaved roads and alleys (21 percent), 

construction-related fugitive dust (17 percent), paved road dust 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

12

(17 percent) and windblown dust (9 percent). 79 FR 7120. 

Section 189(d) requires an approvable plan to show annual five 

percent reductions in PM-10 or PM-10 precursors until 

attainment. The 2012 Five Percent Plan was able to satisfy this 

criterion without assuming additional reductions in agricultural 

emissions.6 Similarly, the 2012 Five Percent Plan demonstrated 

that the area would attain the standard without additional 

reductions in agricultural emissions.7 Instead, the 2012 Five 

Percent Plan predicts that decreases in emissions from other 

categories, primarily construction and windblown dust from 

vacant and open lands, would achieve the requisite 5 percent 

reductions.8 

Recent monitoring data support the attainment demonstration 

in the 2012 Five Percent Plan. 79 FR 7122. Finally, the State 

used no reductions in agricultural emissions for contingency 

measures.9 Because the 2012 Five Percent Plan did not depend on 

additional emission reductions from agricultural sources and 

because EPA finds that the State is not required to reevaluate 

the BACM determinations we made in 2002 as part of meeting the 

requirements of section 189(d), the content of the Ag BMP rule 

 

6 Id. 

7 See MAG 2012 Five Percent Plan, App. B, “Technical Document in Support of 

the MAG 2012 Five Percent Plan for PM-10 for the Maricopa County 

Nonattainment Area,” p. V-65. 

8 Id. at p. III-2, Table III-1. 

9 See MAG 2012 Five Percent Plan, at p.6-39, Table 6-22.
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

13

does not determine the outcome of our action on the 2012 Five 

Percent Plan. 

Nevertheless, EPA is continuing to work with ADEQ, Arizona 

stakeholders and the Governor’s Agricultural BMP Committee to 

improve the Ag BMP rule. EPA anticipates that these 

improvements will be particularly important for addressing PM-10 

emissions in Pinal County, a portion of which EPA re-designated 

as non-attainment in 2012. See 77 FR 32024 (May 31, 2012). 

C. Dust Action General Permit 

Comment: ACLPI commented that the 2012 Five Percent Plan 

relies on an estimate that the Dust Action General Permit (DAGP) 

will increase the rule effectiveness of Rule 310.01 by one 

percent, but argued that it is not clear that the DAGP achieves 

any measurable reduction in emissions. ACLPI stated that the 

structure of the DAGP means that its scope is unclear and that 

there is no way to gauge that issuance of the DAGP is actually 

impacting behavior in a way that reduces emissions. ACLPI 

stated that compliance is only measured by instances of lack of 

compliance discovered by inspectors who happen upon an owner or 

operator of a regulated activity who is not implementing a BMP. 

ACLPI stated that ADEQ has not yet issued a single Requirement 

to Operate (“RTO”), which means that it is possible that sources 

not already subject to permits have implemented BMPs as a result 

of the permit, but it is equally plausible that BMPs are not 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

14

being implemented and that inspectors haven’t discovered the 

violations, or that the universe of potential permittees under 

the DAGP was so small that the adoption of the permit had no 

practical effect whatsoever. 

Response: The 2012 Five Percent Plan does not rely on 

assumptions regarding compliance with the DAGP per se; rather, 

the 2012 Five Percent Plan relies on an assumption that the DAGP 

will improve compliance with Rule 310.01. As the 2012 Five 

Percent Plan explains, “[e]missions reduction credit was taken 

for one new measure, the Dust Action General Permit . . . This 

new measure is expected to raise rule effectiveness for Rule 

310.01 by one percent during high wind hours . . .”10 This 

statement is consistent with Table 5-1 of the MAG 2012 Five 

Percent Plan, “Impact of Increased Rule Effectiveness on 2008-

2012 PM-10 Emissions,” which shows that ADEQ estimated that the 

rule effectiveness for the category “windblown vacant, open, 

test tracts,” (the category of sources subject to Rule 310.01), 

would increase from 96% in 2010-2011 to 97% in 2012.11 Table 5-

1 associates this improved rate of compliance with an annual 

reduction in PM-10 emissions of 149 tons per year.12 

 

10 MAG 2012 Five Percent Plan, p. ES-10 (emphasis added). See also, MAG 2012 

Five Percent Plan at p. 6-45; App. B, “Technical Document in Support of the 

MAG 2012 Five Percent Plan for PM-10 for the Maricopa County Nonattainment 

Area,” ppg. III-1 to III-8. 

11 MAG 2012 Five Percent Plan at p. 5-3, Table 5-1. 

12 Id. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

15

The Maricopa County Air Quality Department’s (MCAQD) 

compliance data for calendar year 2012 support the 2012 Five 

Percent Plan’s assumptions that the DAGP will improve compliance 

with Rule 310.01. MCAQD reviewed its records of inspections 

during calendar year 2012, as documented in “Evaluation of 

Innovative Control Measures and Existing Maricopa County Control 

Measures Contained in the MAG 2012 Five Percent Plan for PM-10 

for the Maricopa County Nonattainment Area, revised,” Maricopa 

County Air Quality Department, June 6, 2013 (2013 Evaluation 

Report).13 It found that, out of a total of 5,431 sites 

inspected for compliance with Rule 310.01 in 2012, 149 citations 

were issued -- amounting to a rule effectiveness rate of 97.62 

percent. 2013 Evaluation Report at pages 3-4. This amount 

exceeds the compliance rate of 96% associated with previous 

years. MAG 2012 Five Percent Plan at p.5-3, Table 5-1. EPA 

acknowledges that estimating rule compliance requires reliance 

on compliance information collected by reliable means. In this 

instance, EPA believes that the information gathered through the 

MCAQD’s inspections program provides information to support the 

conclusion that most affected sources are complying with the 

requirements of Rule 310.01, and that compliance improved in 

2012 as a result of those inspections. 

 

13 MCAQD has committed to conducting this evaluation on a triennial basis. 

MAG 2012 Five Percent Plan, App. C, Exhibit 2, “Maricopa County Resolution to 

Evaluate Measures in the MAG 2012 Five Percent Plan for the Maricopa County 

Nonattainment Area.” 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

16

The 2012 Five Percent Plan further describes the connection 

between Rule 310.01 and the DAGP.14 The Plan explains that the 

DAGP is expected to increase compliance with Rule 310.01 

because, whenever ADEQ issues a forecast of a high wind dust 

event, sources subject to Rule 310.01 (primarily open areas, 

vacant lots, and unpaved parking areas and roadways),15 will take 

additional measures to stabilize open areas and unpaved surfaces 

by implementing the best management practices (BMPs) specified 

in Rule 310.01 and the DAGP.16 Such measures might include 

restricting access to open areas and vacant lots, or by applying 

dust suppressants and/or maintaining surface gravel.17 As 

specified in the DAGP, sources that fail to choose or implement 

a BMP when ADEQ issues a forecast of a high wind dust event may 

trigger applicability of the DAGP and the additional 

requirements it imposes.18 Thus, the existence of the DAGP 

enhances compliance with Rule 310.01 because sources subject to 

Rule 310.01 associate noncompliance with Rule 310.01 with an 

adverse consequence – specifically, the obligation to apply for 

 

14 See MAG 2012 Five Percent Plan, p. ES-10; p. 5-3, Table 5-1; p. 6-45. See 

also MAG 2012 Five Percent Plan, App. B, “Technical Document in Support of 

the MAG 2012 Five Percent Plan for PM-10 for the Maricopa County 

Nonattainment Area,” ppg. III-1 to III-8. The relationship between Rule 

310.01 and the DAGP is also described in ADEQ’s comments on our proposed 

action, Letter from Eric C. Massey, Director, Air Quality Division, ADEQ to 

Greg Nudd, US EPA, dated March 10, 2014. 

15 See Rule 310.01, section 102; 2012 Five Percent Plan at ES-7 to ES-10. 

16 MAG 2012 Five Percent Plan at ES-10. 

17 See DAGP, Attachment C, “Best Management Practice Examples”; Rule 310.01, 

sections 301 – 307. 

18 DAGP, section V. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

17

and comply with the DAGP. Again, MCAQD’s study of the 

compliance rate of Rule 310.01 supports this assumption in the 

2012 Five Percent Plan. 

D. Exceptional Events – General 

 Comment: ACLPI stated that it was unable to reconcile 

some of the numbers of exceptional events cited by EPA. The 

commenter stated that the subtotals in EPA’s concurrence letters 

add up to 131, but the subtotals in the tables in the supporting 

documentation add up to 135. The commenter added that if sites 

with double monitors are counted as only one exceedance, the 

total number of exceedances is 127. 

Response: EPA acknowledges the discrepancy between the 

number of exceedances in concurrence letters and the tables in 

the TSDs. After closely re-reviewing the data, EPA has 

determined that the total number of exceptional events addressed 

by our concurrence letters dated September 6, 2012, May 6, 2013, 

and July 1, 2013 should be 135 exceedances.19 These 135 

exceptional event exceedances occurred on 25 days over the three 

year period, 2010-2012. 

 Comment: ACLPI commented that EPA’s exclusion of such a 

large number of frequent and severe exceedances is 

unconscionable and misrepresents the extent of the particulate 

 

19 See spreadsheet entitled “EPA Exceptional Event Concurrence Sheet,” 

included in the docket for this rule. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

18

pollution in the Area. The commenter stated that the reported 

exceedances are “frequent” and “severe” within the meaning of 

EPA guidance, specifically, EPA’s Interim Guidance on the 

Preparation of Demonstrations in Support of Requests to Exclude 

Ambient Air Quality Data Affected by High Winds Under the 

Exceptional Events Rule, May 2013 (Interim Guidance). 

Response: We note that the 135 exceptional event 

exceedances occurred on 25 days over a three year period from 

2010 to 2012. The determinations reflected in our concurrence 

letters and TSDs dated September 6, 2012, May 6, 2013 and July 

1, 2013 are consistent with the EER and our Interim Guidance. 

We considered a range of relevant factors including whether 

anthropogenic sources had reasonable controls in place, 

meteorological data such as wind speed and direction, and the 

spatial extent of the events. The frequency and severity of the 

events were considered as part of this analysis, and although we 

agree that some of the excluded exceedances could meet the 

criteria for “frequent” and “severe” suggested in our Interim 

Guidance, that fact alone does not disqualify an exceedance from 

consideration as an exceptional event. See Interim Guidance at 

12-13 (frequency and severity of past exceedances may be a 

factor considered in determining the reasonableness of 

controls). Also, the Interim Guidance acknowledges that events 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

19

do not necessarily have to be rare to qualify as exceptional 

events. See Interim Guidance at 3 and 20. 

Comment: ACLPI commented that EPA’s analysis of whether 

the events are reasonably preventable or controllable should 

have been more probing and not a “cookie cutter” approach, given 

the frequency and severity of the exceedances, as well as the 

area’s status as serious nonattainment and the State’s previous 

withdrawal of its earlier Five Percent Plan. 

Response: The State submitted documentation on March 14, 

2012, January 28, 2013, and February 13, 2013 to demonstrate to 

EPA that exceedances of the PM-10 NAAQS on various dates in 2011 

and 2012 meet the criteria for an exceptional event in the EER. 

The State’s submittals comprise over 1750 pages of documentation 

of the facts supporting each of the identified exceptional 

events. Our TSDs accompanying our concurrence letters dated 

September 6, 2012, May 6, 2013, and July 1, 2013 reflect EPA’s 

methodical and systematic review of the State’s documentation of 

the events and EPA’s technical expertise and judgment. EPA 

presented its conclusions in a standardized format that was 

appropriate, considering the volume of information presented and 

reviewed, as well as the purpose of informing the public. In 

addition, EPA notes that we also received several comments in 

this rulemaking regarding the process required to document 

exceedances as “exceptional events” contending that the level of 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

20

resources required to prepare and submit such documentation to 

EPA was too onerous. 

Comment: ACLPI commented that the events excluded by EPA 

were predictable and seasonal in nature and could be ameliorated 

if the State adopted appropriate control measures for windblown 

dust both in the attainment (sic) area and statewide. 

Response: For each of the events that EPA concurred with, 

EPA found that the event was not reasonably controllable or 

preventable (nRCP). EPA’s Interim Guidance states that, for 

anthropogenic sources of dust, “a high wind dust event may . . . 

be considered to be not reasonably controllable or preventable 

if: (1) the anthropogenic sources of dust have reasonable 

controls in place; (2) the reasonable controls have been 

effectively implemented and enforced; and (3) the wind speed was 

high enough to overwhelm the reasonable controls.” See Interim 

Guidance at 10. 

EPA’s determinations of nRCP were primarily based on 

consideration of the control requirements based on the Area’s 

serious nonattainment classification for the PM-10 NAAQS. See

Interim Guidance at 13. ADEQ provided detailed information of 

required controls (including BACM-level controls for significant 

sources previously approved by EPA for this area), as well as 

information on rule implementation, rule effectiveness, 

compliance and enforcement, alert systems and public 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

21

notification activities. A typical example is the documentation 

ADEQ submitted in connection with the event that occurred on 

August 11, 2012. State of Arizona, Exceptional Event 

Documentation for the Event of August 11, 2012 for the Phoenix 

PM10 Nonattainment Area, February 2013 (AZ EE Documentation for 

August 11, 2012). This submittal included a list of control 

measures regulating sources of dust in Maricopa and Pinal 

counties, information about rule effectiveness, and data 

regarding compliance and enforcement. See AZ EE Documentation 

for August 11, 2012, Section 5. 

In addition, EPA’s determinations of nRCP were based on 

ADEQ’s documentation of wind speeds. For example, the 

exceedances that occurred on September 11 and 12, 2011 involved 

wind speeds of 20 miles per hour (mph) and 25 mph, respectively. 

See e.g., EPA Letter dated July 1, 2013, and accompanying TSD at 

p. 4. See also, e.g., TSD discussion of June 16, 2012 event at 

p. 10 (sustained wind speeds of 29 mph – 32 mph); TSD discussion 

of June 27, 2012 event at p. 15 (sustained wind speeds of 31 mph 

– 38 mph); TSD discussion of July 11, 2012 event at p. 20 

(sustained wind speeds of 20 mph – 25 mph).20 Given the wind 

 

20 The commenter did not specify particular dates or exceedances for which she 

found EPA’s analysis deficient; therefore, EPA’s response provides just a few 

examples from our TSDs in which we refer to the documentation of wind speeds

included in the State’s submittals. We reiterate, however, that our review 

of the State’s submittals involved a methodical, case-by-case approach as 

documented by each of the TSDs accompanying our concurrence letters dated 

September 6, 2012, May 6, 2013 and July 1, 2013. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

22

speeds associated with each of the events that EPA concurred 

upon, EPA believes ADEQ’s controls assessment was appropriate 

and that the pre-existing and previously approved BACM level 

controls are adequate for meeting the requirement of “reasonable 

controls” for a PM-10 serious nonattainment area. 

Additional information regarding EPA’s consideration of 

reasonable controls can be found in EPA’s TSDs for each event. 

E. Exceptional Events and Reasonable Controls 

Comment: ACLPI commented that BACM level controls were not 

in place in the nonattainment area. ACLPI commented that EPA’s 

Interim Guidance says that BACM measures may be insufficient if 

the SIP has not been recently reviewed and that EPA has 

indicated that it will consider windblown dust BACM to be 

reasonable controls for purposes of exceptional events claims if 

the measures have been reviewed and approved in the context of a 

SIP revision within the past three years and if the measures are 

specific to windblown dust. ACLPI commented that EPA’s proposed 

action departs from this guidance because EPA last approved BACM 

for the area in 2002, with a supplemental analysis in 2006. 

Response: EPA’s Interim Guidance states: “Generally, the 

EPA will consider windblown dust BACM to constitute reasonable 

controls if these measures have been reviewed and approved in 

the context of a SIP revision for the emission source area 

within the past three years.” Interim Guidance at 15. Although 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

23

our BACM determinations were made outside this recommended time 

frame, we believe that our determinations regarding nRCP were 

correct. First, the 2012 Five Percent Plan shows that the 

significant stationary source categories for PM-10 are: 

construction; unpaved roads and alleys; paved road dust; 

windblown dust (non-agriculture); unpaved parking lots; and offroad recreational vehicles.21 Each of these source categories 

was included in our earlier BACM determinations. See 67 FR 

48718 (July 25, 2002); see also, 67 FR 48733-34. Because the 

significant sources within the Phoenix PM-10 nonattainment area 

have not significantly changed since 2002, and the range of 

potential measures for controlling emissions from these source 

categories (e.g., stabilization of disturbed surface areas; 

spray bars to apply water or dust suppressants; track out, 

rumble grate and wheel washer requirements) have not 

significantly changed since 2002, we believe that our previous 

BACM determinations remain appropriate for the purposes of 

making exceptional event determinations, including 

determinations regarding nRCP. 

Second, although the State has not prepared a new BACM 

analysis and EPA has not made new BACM determinations in the 

past three years, Arizona has adopted revisions to rules 

regulating sources of windblown dust that EPA has approved into 

 

21 MAG 2012 Five Percent Plan, at -. 5-7, Table 5-3. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

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the SIP because they are more stringent. Specifically, EPA has 

approved updated revisions of: Rule 310, which regulates 

sources of fugitive dust from dust generating operations such as 

construction; Rule 310.01, which regulates sources of windblown 

dust from open areas, vacant lots, unpaved parking lots, and 

unpaved roadways; and Rule 316, which regulates sources of dust 

from nonmetallic mineral processing. 22 

Third, to the extent the commenter interprets the Interim 

Guidance as stating that a BACM determination that is older than 

three years cannot be relied upon in a demonstration of 

reasonable controls, the commenter is incorrect. The Interim 

Guidance provides a guideline to states preparing documentation 

to submit to EPA that more recent BACM determinations will 

generally satisfy EPA’s consideration of reasonable controls. 

It does not disqualify measures that EPA determined to be BACM 

more than three years previously from consideration as 

reasonable controls, nor does it impose an obligation on the 

part of the state or EPA to re-evaluate BACM. 

Comment: ACLPI commented that EPA found that the 2007 

Maricopa BMP Rule no longer represents BACM for agricultural 

emissions (referencing statements in a 2010 proposed rulemaking 

and in a 2010 letter to the Arizona Agricultural Best Management 

 

22 See 74 FR 58554 (November 13, 2009) (EPA approval of Maricopa County’s 

revisions to Rule 316, adopted on March 12, 2008); 75 FR 78167 (December 15, 

2010) (EPA approval of Maricopa County’s revisions to Rule 310 and 310.01, 

adopted on January 27, 2010). 
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Practices (BMP) Committee) and that although the 2007 Maricopa 

BMP Rule was revised in 2011, the revisions were not implemented 

until March 2012. The commenter states that 98 of the 217 

exceedances at issue occurred in 2011 (i.e., prior to the 

implementation of the 2011 Maricopa BMP Rule revisions). The 

commenter argued that even into 2012, the “revised Maricopa BMP 

Rule” (which EPA understands to be a reference to the 2011 

Maricopa BMP Rule) is not clearly BACM because it did not 

include EPA’s recommendations for improvement. The commenter 

concludes that EPA’s concurrence on exceptional events was 

erroneous because EPA relied on its prior approval of the 

State’s previous BACM demonstration and did not attempt to 

determine whether the controls in place during the event were 

BACM. 

Response: Our response above explains why the CAA does not 

require EPA to reevaluate its earlier BACM determination in 

connection with our action on the 2012 Five Percent Plan. We 

understand the commenter to be asserting another basis for EPA 

to reevaluate BACM, in particular, that EPA’s concurrence on 

exceptional events may be a basis to require EPA to make a 

determination regarding BACM. EPA’s Interim Guidance, however, 

states that BACM for windblown dust is a measure that EPA has 

identified as being “reasonable” for the purposes of exceptional 

events determinations. Interim Guidance at 15. The Interim 
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Guidance acknowledges that “[h]aving BACM/RACM in place during 

the time of the event is an important consideration” for an 

exceptional event determination, but more justification may be 

necessary if, for example, the measures are not related to 

windblown dust, or if the SIP has not been recently reviewed. 

Id. For the reasons set forth below, EPA’s reliance on the BACM 

determinations it made in 2002 was a reasonable basis to concur 

on the State’s exceptional event claims.23 

First, the 2008 Inventory shows that agricultural sources 

are a very small contributor to windblown dust in Maricopa 

County. According to the 2008 Inventory, agricultural windblown 

dust comprises approximately 0.9% of the total annual windblown 

dust emissions in the nonattainment area (448 tons out of a 

total of 49,673.01 tons in 2012).24 Other agricultural sources, 

such as tilling, harvesting, and cotton ginning, comprise 

approximately 1.8% of the total annual PM-10 emissions inventory 

(893 tons out of a total of 49,673.01 tons in 2012).25 Thus, 

 

23 EPA notes that it applies a weight-of-the-evidence standard in evaluating 

exceptional events claims. See e.g., Interim Guidance at 8: “The EPA uses a 

weight-of-the-evidence approach in reviewing air agency requests for data 

exclusion under the EER [Exceptional Events Rule]. Evidence and narrative 

that constitute a strong demonstration for one element can also be part of 

the demonstration for another element, but cannot make up for the absence of 

or insufficient explanation supporting another element. A strong 

demonstration for one requirement could, however, influence the 

persuasiveness of the demonstration for another.” 

24 Id. at p. II-3, Table II-2; see also, MAG 2012 Five Percent Plan at p. 5-5, 

Table 5-2. 

25 Id. 
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agricultural sources contribute only a relatively small 

percentage of the total emissions in the 2008 Inventory. 

Second, in determining that the exceedances that occurred 

in 2011 and 2012 were nRCP, it was appropriate for EPA to find 

that the existing controls were “reasonable” because, as we 

explained above, the State met the requirements of section 

189(d) in the 2012 Five Percent Plan without relying on 

additional reductions from agricultural sources. Significantly, 

no additional reductions from the Maricopa BMP Rule were needed 

to demonstrate that the area would attain the standard.26 

Therefore, our determination that existing BACM requirements 

were sufficient to find that emissions sources were reasonably 

controlled at the time the exceedances occurred was appropriate. 

Third, we acknowledge that EPA has previously indicated to 

the State that improvements to controls on agricultural sources 

should be considered. It is important to note, however, that 

EPA’s proposed 2010 rulemaking was a proposed action to 

disapprove a different section 189(d) plan, the State’s 2007 

Five Percent Plan, in part because of EPA’s concerns regarding 

the accuracy of the State’s 2005 Periodic Emission Inventory. 

(We also note that the proposed rulemaking was never finalized.) 

It is also important to note that EPA’s comments to the Ag BMP 

Committee predate the finalization of the 2008 Emission 

 

26See MAG 2012 Five Percent Plan, at p. 5-7, Table 5-3. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

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Inventory (May 2012) in which emissions from agricultural 

sources are a small part of the PM-10 emissions inventory. 

Further, although the 2008 Inventory indicates that agricultural 

sources are relatively small contributors to PM-10 emissions in 

the Maricopa County PM-10 Nonattainment Area, EPA believes that 

agriculture is a significant source in certain portions of Pinal 

County, which EPA recently redesignated as a PM-10 nonattainment 

area. See 77 FR 32024 (May 31, 2012). Therefore, EPA believes 

that it is important to continue to improve the controls on 

agricultural sources, and EPA is working with ADEQ, 

stakeholders, and the Governor’s Agricultural BMP Committee to 

improve these controls. 

Comment: ACLPI commented that ADEQ and EPA did not 

adequately address the issue of whether the events were 

reasonably controllable or preventable with respect to sources 

outside the Maricopa County PM-10 Nonattainment Area. ACLPI 

stated that EPA’s Interim Guidance says that a basic controls 

analysis should consider all upwind areas of disturbed soil to 

be potential contributing sources, and that the basic controls 

analysis should identify all contributing sources in upwind 

areas and provide evidence that such sources were reasonably 

controlled, whether anthropogenic or natural, and include 

inspection reports and/or notices of violation, if available. 
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The commenter stated that ADEQ and EPA did not indicate that 

control measures outside of Maricopa County were evaluated for 

their “reasonableness.” ACLPI commented that Pinal County’s 

controls are “minimalist rules” that do not require controls to 

address emissions caused solely by high wind events and that 

although Pinal County was only recently designated 

nonattainment, Pinal County should not be excused from the 

requirement to show that sources in the county were subject to 

reasonable controls. 

Response: The comment concerns the level of controls 

imposed on sources outside the Maricopa County PM-10 

Nonattainment Area, in particular, sources located in Pinal 

County. As noted in our proposed action, the Maricopa County 

PM-10 Nonattainment Area encompasses several cities within 

Maricopa County (including the cities of Phoenix, Mesa, 

Scottsdale, Tempe, Chandler, and Glendale), and several other 

smaller jurisdictions and unincorporated county lands. The 

Maricopa County PM-10 Nonattainment Area also includes the town 

of Apache Junction in Pinal County. Recently, EPA designated a 

portion of Pinal County (“West Pinal”) as a moderate PM-10 

nonattainment area, which triggered nonattainment planning 
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obligations that the State must fulfill. See 77 FR 32024 (May 

31, 2012).27 

EPA’s Interim Guidance contemplates that a basic controls 

analysis should include “a brief description” of upwind sources. 

The level of detail provided in describing the Pinal County 

sources was adequate given relevant factors such as wind speed. 

Moreover, ADEQ and EPA both indicated that they evaluated 

control measures outside of Maricopa County. For example, 

ADEQ’s exceptional event documentation included an analysis of 

reasonable controls that identified measures that apply to 

sources located within the Maricopa County PM-10 Nonattainment 

Area, and measures applicable to sources in Pinal County, 

outside the Maricopa County PM-10 Nonattainment Area.28 ADEQ 

specifically identified two Pinal County rules, Article 2, 

Fugitive Dust, and Article 3, Construction Sites – Fugitive 

Dust, as regulatory control measures.29 EPA’s TSDs also 

 

27 We note that our action on the 2012 Five Percent Plan relates to our 

concurrences with the State’s exceptional event claims for exceedances at 

monitors for the Maricopa County PM-10 Nonattainment Area dated September 6, 

2012, May 6, 2013, and July 1, 2013. Our action on the 2012 Five Percent 

Plan does not depend on data from monitors located within the newly 

redesignated West Pinal PM-10 Nonattainment Area or on any exceptional events 

claims regarding data from such monitors. 

28 See e.g., ADEQ EE Documentation for July 3-8, 2011 at 39-45; in particular, 

ppg. 40-41, Tables 4-1 and 4-3 (sources within the Maricopa PM-10 

Nonattainment Area) and Table 4-2 (sources outside the Maricopa PM-10 

Nonattainment Area). 

29 Id. at 41, Table 4-2. 
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referenced this section of ADEQ’s documentation, including the 

discussion of rules applicable to sources in Pinal County.30 

In addition, the level of detail describing Pinal County 

sources and controls was also adequate for an area such as Pinal 

County for which a portion was recently redesignated as a PM-10 

nonattainment area and is currently undergoing the nonattainment 

planning process. As EPA’s Interim Guidance states, an area’s 

attainment status is an appropriate guideline for assessing the 

reasonableness of controls: “Generally, the EPA does not expect 

areas classified as attainment, unclassifiable, or maintenance 

for a NAAQS to have the same level of controls as areas that are 

nonattainment for the same NAAQS. Also, if an area has been 

recently designated to nonattainment but has not yet been 

required to implement controls, the EPA will expect the level of 

controls that is appropriate for the planning stage.” Interim 

Guidance at 15. EPA’s recent redesignation of a portion of 

Pinal County as a moderate PM10 nonattainment area triggered CAA 

planning obligations for the State to develop regulations to 

implement controls such as Reasonably Available Control Measures 

(RACM) for existing sources of PM-10 and a section 173 

preconstruction permitting program for new and modified sources 

of PM-10. EPA concurred with exceedances that occurred in 2011 

and 2012; the latest exceedance occurred on September 6, 2012, 

 

30 See e.g., EPA Letter dated Sept. 9, 2012 and accompanying TSD at 3. 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

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well before the CAA’s deadline for Arizona to submit an 

implementation plan to EPA for approval into the Arizona SIP. 

See 77 FR 32030. 

Comment: ACLPI commented that claims that events were 

caused by “winds transporting dust from desert areas of Pima and 

Pinal Counties” are not substantiated and that the State’s 

demonstrations do not determine source locations, as required by 

EPA’s 2013 Interim Guidance (referencing 3.1.5.1). ACLPI 

conducted its own analysis of the event that occurred on July 

18, 2011. ACLPI commented that its analysis indicates that dust 

sources included agricultural sources in Pinal and Maricopa 

Counties, and that four downdrafts and four outflows impacted 

the monitors from multiple locations, in contrast to the State’s 

assertion that one thunderstorm outflow transported dust from 

desert portions of Pinal and Pima counties into the Phoenix PM10 nonattainment area. ACLPI stated that although the State 

claims that specific source areas are difficult to determine 

because of the less dense monitoring network in the general 

source area, ACLPI’s analysis shows that likely source locations 

can be determined using meteorological modeling and 

observational data. Therefore, EPA should require the state to 

make a more concerted effort to identify the actual sources and 

adopt controls to avoid or ameliorate future events. 
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Response: Although a more refined analysis of the location 

of thunderstorm downdrafts and source areas is potentially 

helpful for certain high wind dust events, this additional 

analysis is not necessary to analyze the specific events that 

EPA concurred on. EPA reviewed the commenter’s analysis and 

concluded that it does not contradict ADEQ’s documentation, but 

rather corroborates the evidence presented in ADEQ's 

demonstration. ADEQ’s documentation states that the 

contributing source regions were somewhat widespread, but that 

the “majority” of the PM that was transported into Maricopa 

County likely originated from areas within Pinal County to the 

south and southeast of Maricopa County.31 ADEQ also explained 

that it is likely that some dust was generated within the 

Maricopa County PM10 Nonattainment Area as gusts from the 

thunderstorm outflows passed through the area.32 Thus, ADEQ did 

not claim that all the emissions were specifically caused by a 

single thunderstorm outflow. ADEQ’s statement that the 

"majority" of the emissions were transported from areas of Pinal 

County and southeast Maricopa County is supported by the 

visualization of images from the Phoenix visibility camera 

included in the July 18, 2011 demonstration, which shows a large 

 

31 State of Arizona Exceptional Event Documentation for the Event of July 18, 

2011, for the Phoenix PM-10 Nonattainment Area, Jan. 23, 2013 at p. 9. 

32 Id. at 18. 
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dust storm approaching from the south of the Maricopa County PM10 Nonattainment Area.33 

Comment: ACLPI commented that the fact that some of the 

sources are located outside of the Maricopa County PM-10 

Nonattainment Area does not absolve the State of its 

responsibility to ensure that they are reasonably controlled. 

The commenter stated that ADEQ is the single responsible actor 

for air quality control in Arizona and had the responsibility to 

address the public health risk presented by sources in Pinal 

County, particularly given high wind events experienced in 2008 

and 2009. 

Response: EPA agrees that the State has a responsibility 

to ensure that sources outside the Maricopa County PM-10 

Nonattainment Area are reasonably controlled. Our action with 

respect to exceedances at Maricopa County PM-10 Nonattainment 

Area monitors does not absolve in any way the State’s 

responsibility to address PM-10 emissions in the West Pinal PM10 Nonattainment Area. Our July 2012 redesignation of West 

Pinal to nonattainment triggers Clean Air Act nonattainment 

planning obligations that Arizona must fulfill. See 77 FR 

32030. We note that our action on the 2012 Five Percent Plan 

relates to our concurrences with the State’s exceptional event 

claims for exceedances at monitors for the Maricopa County PM10 

 

33 Id. at 27. 
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Nonattainment Area dated September 6, 2012, May 6, 2013, and 

July 1, 2013, and does not depend on the treatment of data for 

monitors located within the newly redesignated West Pinal PM-10 

Nonattainment Area. 

F. Exceedances in 2013 

Comment: ACLPI commented that the Maricopa County PM-10 

Nonattainment Area experienced 30 exceedances over six days in 

2013, which ADEQ has flagged and for which ADEQ is preparing EE 

documentation, and that EPA is simply assuming that it will 

concur with these EE demonstrations. The commenter stated that 

this is unsupportable, particularly in light of EPA’s failure to 

require mitigation measures and that there are frequent and 

severe violations of the standard at multiple monitors, many of 

which are located in low income neighborhoods. 

Response: The 2012 Five Percent Plan was based on a 

projection that that the Area would attain the NAAQS in 2012. 

If, upon review of the available evidence, EPA finds that the 

exceedances of the standard in 2013 constitute a new violation 

of the PM-10 NAAQS, we have the authority to require the state 

to submit a SIP revision with additional controls and a 

demonstration that the new controls will bring the area back 

into attainment with the standard.34

 

34 E.g., under CAA section 110(k)(5) EPA may require a state to revise its 

SIP if we find it to be substantially inadequate to maintain the relevant air 

quality standard. In such a situation, EPA notifies a state of the 
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G. Contingency Measures 

Comment: ACLPI stated that EPA’s proposal acknowledges 

that the contingency measures in the 2012 Five Percent Plan are 

already being implemented. The commenter stated that CAA 

(175(d)) envisions additional measures that are automatically 

and immediately implemented if a milestone for reasonable 

further progress or attainment is not met. The commenter stated 

that if contingency measures are already being implemented when 

a milestone is missed, continued implementation will not ensure 

that the situation will be corrected. The commenter argues that 

LEAN v. EPA is not binding on the 9th Cir. and is contrary to 

the plain language of the CAA. The commenter stated that 

approval of the 2012 Five Percent Plan without meaningful and 

appropriate contingency measures is contrary to law. 

Response: EPA disagrees with the comment. Contingency 

measures must provide for additional emission reductions that 

are not relied on for RFP or attainment and that are not 

included in the attainment demonstration. Nothing in the 

statute precludes a state from implementing such measures before 

they are triggered. See, e.g., LEAN v. EPA, 382 F.3d 575 (5th 

Cir. 2004) (upholding contingency measures that were previously 

 

inadequacies and can allow the state up to 18 months to submit revisions to 

the SIP to address the problems. See 42 U.S.C. 7410(k)(5). 
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required and implemented where they were in excess of the 

attainment demonstration and RFP SIP). 

EPA has approved numerous SIPs under this interpretation—

i.e., SIPs that use as contingency measures one or more Federal 

or local measures that are in place and provide reductions that 

are in excess of the reductions required by the attainment 

demonstration or RFP plan. See, e.g., 62 FR 15844 (April 3, 

1997) (direct final rule approving an Indiana ozone SIP 

revision); 62 FR 66279 (December 18, 1997) (final rule approving 

an Illinois ozone SIP revision); 66 FR 30811 (June 8, 2001) 

(direct final rule approving a Rhode Island ozone SIP revision); 

66 FR 586 (January 3, 2001) (final rule approving District of 

Columbia, Maryland, and Virginia ozone SIP revisions); and 66 FR 

634 (January 3, 2001) (final rule approving a Connecticut ozone 

SIP revision). 

The scenario described by the commenter that alreadyimplemented contingency measures will be a problem if the 

Maricopa County PM-10 Nonattainment Area misses a deadline for 

RFP or attainment is mitigated by the fact that monitoring data 

for 2010-2012 show that the Area already attained the 24-hour 

PM-10 NAAQS as of December 12, 2012. See 79 FR 7122. Our 

approval of the contingency measures is also consistent with EPA 

guidance that “the potential nature and extent of any attainment 

shortfall for the area” is relevant to the determining the level 
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38

of required emission reductions and that contingency measures 

“should represent a portion of the actual emission reductions 

necessary to bring about attainment in area.” 72 FR 20586, 

20643; see also PM-10 Addendum at 42015 (the emission reductions 

anticipated by the contingency measures should be equal to 

approximately one-year's worth of emission reductions needed to 

achieve RFP for the area.) EPA’s approval of contingency 

measures that are already being implemented is particularly 

appropriate where, as is the case for the Maricopa County PM-10 

Nonattainment Area, there are no future RFP or attainment 

deadlines. 

H. Other Comments

Comment: ADEQ asked that EPA clarify that this action 

applies to the entire nonattainment area, including the portion 

in Pinal County, and not just to the Maricopa County portion. 

Response: EPA has made this clarification. 

Comment: Several commenters noted that the plan was 

developed through a cooperative discussion among the many 

stakeholders in the plan. According to the commenters, this 

process led to innovative strategies that are appropriate to the 

local conditions and consistent with EPA requirements. 

Response: EPA acknowledges these comments. 

Comment: Several commenters expressed concerns about the 

resources required to demonstrate that measured exceedances of 
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May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

39

the standard are due to exceptional events. These commenters 

recommended changing the Exceptional Events Rule to address this 

issue. 

Response: EPA will consider these comments in future 

rulemakings on the Exceptional Events Rule. 

III. EPA's Final Action 

As a result of our proposed rule and our response to 

comments above, we are finalizing our proposal to approve the 

2012 Five Percent Plan as meeting the requirements of the CAA 

for the Maricopa County PM-10 nonattainment area. Specifically, 

we are approving: 

(A) The 2008 baseline emissions inventory and the 2007, 

2009, 2010, 2011 and 2012 projected emission inventories as 

meeting the requirements of CAA section 172(c)(3); 

(B) the attainment demonstration as meeting the 

requirements of CAA sections 189(d) and 179(d)(3); 

(C) the five percent demonstration as meeting the 

requirements of CAA section 189(d); 

(D) the reasonable further progress and quantitative 

milestone demonstrations as meeting the requirements of CAA 

sections 172(c)(2) and 189(d); 

(E) the contingency measures as meeting the requirements of 

CAA section 172(c)(9); and 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

40

(F) the motor vehicle emissions budget as compliant with 

the budget adequacy requirements of 40 CFR 93.118(e). 

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, 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 Order 12866 (58 FR 51735, October 4, 1993); 

· 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.); 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

41

· 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 EPA with the discretionary authority to 

address, as appropriate, disproportionate human health or 

environmental effects, using practicable and legally 

permissible methods, under Executive Order 12898 (59 FR 

7629, February 16, 1994). 

In addition, this rule does not have tribal implications as 

specified by Executive Order 13175 (65 FR 67249, November 9, 

2000), because it does not apply in Indian country located in 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

42

the State, and EPA notes that it will not impose substantial 

direct costs on tribal governments or preempt tribal law. 

The Congressional Review Act, 5 U.S.C. 801 et seq., as 

added by the Small Business Regulatory Enforcement Fairness Act 

of 1996, generally provides that before a rule may take effect, 

the agency promulgating the rule must submit a rule report, 

which includes a copy of the rule, to each House of the Congress 

and to the Comptroller General of the United States. EPA will 

submit a report containing this action and other required 

information to the U.S. Senate, the U.S. House of 

Representatives, and the Comptroller General of the United 

States prior to publication of the rule in the Federal Register. 

A major rule cannot take effect until 60 days after it is 

published in the Federal Register. This action is not a “major 

rule” as defined by 5 U.S.C. 804(2). 

Under section 307(b)(1) of the CAA, petitions for judicial 

review of this action must be filed in the United States Court 

of Appeals for the appropriate circuit by [INSERT DATE 60 DAYS 

FROM DATE OF PUBLICATION IN THE FEDERAL REGISTER]. Filing a 

petition for reconsideration by the Administrator of this final 

rule does not affect the finality of this action for the 

purposes of judicial review nor does it extend the time within 

which a petition for judicial review may be filed, and shall not 

postpone the effectiveness of such rule or action. This action 
This document is a prepublication version, signed by Jared Blumenfeld, Regional Administrator, EPA Region 9 on 

May 30, 2014. We have taken steps to ensure the accuracy of this version, but it is not the official version. 

43

may not be challenged later in proceedings to enforce its 

requirements (see section 307(b)(2)). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air pollution control, 

Intergovernmental relations, Incorporation by reference, 

Particulate matter, Reporting and recordkeeping requirements. 

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

_____________________ ___________________________ 

Dated: Jared Blumenfeld, 

 Regional Administrator, 

Region IX. 

 
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Part 52, Chapter I, Title 40 of the Code of Federal Regulations 

is amended as follows: 

PART 52 APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS. 

1. The authority citation for Part 52 continues to read as 

follows: 

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

Subpart D — Arizona 

2. Section 52.120 is amended by adding paragraph 

(c)(157)(ii)(A)(1) and (2) to read as follows: 

§ 52.120 Identification of plan.

* * * * * 

(c) * * * 

(157) * * * 

(i) * * * 

(ii) Additional materials. 

(A) Arizona Department of Environmental Quality 

(1) 2012 Five Percent Plan for PM-10 for the Maricopa County 

Nonattainment Area, and Appendices Volume One and Volume Two, 

adopted May 23, 2012. 

(2) 2012 Five Percent Plan for PM-10 for the Pinal County 

Township 1 North, Range 8 East Nonattainment Area, adopted May 

25, 2012. 

* * * * *