

[Federal Register: July 12, 2006 (Volume 71, Number 133)]
[Proposed Rules]               
[Page 39251-39259]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr12jy06-29]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2006-0526; FRL-8192-3]

 
Approval and Promulgation of Implementation Plans; Arizona--
Phoenix PM-10 Nonattainment Area; Salt River Area Plan for Attainment 
of the 24-Hour PM-10 Standard

AGENCY: Environmental Protection Agency (EPA).

[[Page 39252]]


ACTION: Proposed rule.

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SUMMARY: EPA proposes to approve under the Clean Air Act (CAA) 
provisions of the Revised PM-10 State Implementation Plan for the Salt 
River Area submitted by the State of Arizona to EPA in October and 
November 2005. These submittals include adopted rules and commitments 
that address particulate matter (PM-10) emissions from fugitive dust 
sources. EPA is proposing to approve these submittals as meeting the 
best available control measure (BACM) requirements of CAA section 
189(b)(1)(B) and the most stringent measure requirement (MSM) of 
section 188(e) or as strengthening the state implementation plan (SIP). 
We are taking comments on this proposal and plan to follow with a final 
action.

DATES: Any comments must arrive by August 11, 2006. Comments should be 
addressed to the contact listed below.

ADDRESSES: Submit comments, identified by docket number [DOCKET 
NUMBER], by one of the following methods:
    1. Federal eRulemaking Portal: http://www.regulations.gov. Follow the on-

line instructions.
    2. E-mail: irwin.karen@epa.gov
    3. Mail or deliver: Karen Irwin (AIR-2), U.S. Environmental 
Protection Agency Region IX, 75 Hawthorne Street, San Francisco, CA 
94105-3901.
    Instructions: All comments will be included in the public docket 
without change and may be made available on-line at 
http://www.regulations.gov, including any personal information provided, 

unless the comment includes Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. 
Information that you consider CBI or otherwise protected should be 
clearly identified as such and should not be submitted through 
http://www.regulations.gov or e-mail www.regulations.gov is an ``anonymous 

access'' system, and EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send e-mail directly to EPA, your e-mail address will be automatically 
captured and included as part of the public comment. If EPA cannot read 
your comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment.
    Docket: The index to the docket for this action, including the EPA 
technical support document (TSD) and other relevant material, is 
available electronically at http://www.regulations.gov and in hard copy at EPA 

Region IX, 75 Hawthorne Street, San Francisco, California. While all 
documents in the docket are listed in the index, some information may 
be publicly available only at the hard copy locations (e.g., 
copyrighted material), and some may not be publicly available in either 
location (e.g., CBI). To inspect the hard copy materials, please 
schedule an appointment during normal business hours with the contact 
listed in the FOR FURTHER INFORMATION CONTACT section.
    Copies of the state implementation plan (SIP) materials are also 
available for inspection at the addresses listed below:

Arizona Department of Environmental Quality, 1110 W. Washington Street, 
Phoenix, AZ 85007.
Maricopa County Air Quality Department, 1001 N. Central Ave., Suite 
200, Phoenix, AZ 85004.

FOR FURTHER INFORMATION CONTACT: Karen Irwin, Office of Air Planning 
(AIR-2), U.S. Environmental Protection Agency, Region 9, 75 Hawthorne 
Street, San Francisco, California 94105. (415) 947-4116, e-mail: 
irwin.karen@epa.gov.


SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and 
``our'' refer to EPA.

Table of Contents

I. Summary of Today's Proposal
    A. Arizona Department of Environmental Quality (ADEQ) Submittals 
for the Salt River Area
    B. Completeness of the SIP Submittal
II. Applicable CAA Requirements
    A. Best Available Control Measures (BACM) and Most Stringent 
Measures (MSM)
    B. General SIP Requirements
III. Evaluation of Adopted Measures and Commitments
    A. Summary
    B. Rules 316 and 325
    1. Rule Revisions and New Rule
    2. Enforcement Resources and Methods
    3. Conclusion
    C. Rules 310 and 310.01 and Related Submittals
    1. Rule Revisions and New Rule
    2. Enforcement Resources and Methods
    3. Conclusion
    D. City of Phoenix Alluvial Channels Commitment
    E. Municipality, County, and State Paved Road Re-Entrained Dust 
Commitments
IV. Statutory and Executive Order Reviews

I. Summary of Today's Proposal

A. Arizona Department of Environmental Quality (ADEQ) Submittals for 
the Salt River Area

    The Salt River area, located in metropolitan Phoenix, is a 32-
square mile subarea of the Metropolitan Phoenix (Maricopa County) 
serious PM-10 nonattainment area. ADEQ has submitted multiple PM-10 
plans for the Salt River area, beginning with a January 27, 2004 
submittal and followed by August 2, 2004 and August 29, 2005 
submittals. An October 7, 2005 submittal, Revised PM-10 State 
Implementation Plan for the Salt River Area, and a supplemental 
November 29, 2005 submittal, Revised PM-10 State Implementation Plan 
for the Salt River Area Additional Submittals, supersede the previous 
three submittals and contain the measures that are the subject of this 
proposed rule. Included with the October 7, 2005 plan submittal are 
attachments, a technical support document (TSD), and appendices to both 
the plan and TSD. Hereafter, we refer to the October 2005 submittal as 
``Salt River plan'' and the TSD as ``Salt River TSD''. We refer to the 
November 2005 submittal as ``Salt River plan supplement.'' \1\
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    \1\ For additional background on the Salt River portion of the 
Phoenix PM-10 nonattainment area, see 67 FR 19148 (April 18, 2002) 
and 67 FR 44369 (July 2, 2002). On July 25, 2002, EPA approved 
multiple documents submitted to EPA by Arizona for the Phoenix area 
as meeting the CAA requirements for serious PM-10 nonattainment 
areas for the 24-hour and annual PM-10 national ambient air quality 
standards (NAAQS). Among these documents is the ``Revised Maricopa 
Association of Governments (MAG) 1999 Serious Area Particulate Plan 
for PM-10 for the Maricopa County Nonattainment Area,'' February 
2000 (MAG plan), that includes the BACM demonstrations for all 
significant source categories (except agriculture) for both the 24-
hour and annual PM-10 standards and the State's request and 
supporting documentation, including the most stringent measure (MSM) 
analysis (except for agriculture) for an attainment date extension 
to 2006 for both standards. EPA's July 25, 2002 final action 
included approval of these elements of the MAG plan. See EPA's 
proposed and final approval actions at 65 FR 19964 (April 13, 2000), 
66 FR 50252 (October 2, 2001) and 67 FR 48718 (July 25, 2002).
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    While measures contained in the Salt River plan address monitored 
exceedences of EPA's 24-hour PM-10 national ambient air quality 
standard (NAAQS) \2\ that occurred in that area, they apply to the 
entire Phoenix PM-10 nonattainment area. This is because the Salt River 
monitors were sited to be representative of air quality at other sites 
in the Phoenix PM-10 nonattainment area with similar emissions sources. 
See 62 FR 31025, 31030 (June 6, 1997).
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    \2\ The PM-10 24-hour standard is 150 [mu]g/m3. 40 
CFR 50.6.

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[[Page 39253]]

    The following rules, requirements and resolutions have been 
submitted as part of the Salt River plan or the Salt River plan 
supplement.\3\ We are proposing to approve them into the Arizona SIP 
pursuant to the listed CAA sections.

------------------------------------------------------------------------
        Rule/measure/commitment              Relevant CAA section(s)
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MCAQD Rule 316 ``Nonmetallic Mineral     189(b)(1)(B) and 188(e).
 Processing'', adopted June 8, 2005.
MCAQD Rule 325 ``Brick and Structural    189(b)(1)(B) and 188(e).
 Clay Products (BSCP) Manufacturing'',
 adopted August 10, 2005.
Maricopa County Air Quality Department   189(b) and 188(e) for
 (MCAQD) Rule 310 ``Fugitive Dust'',      subsections 304.5 and 502.
 adopted April 7, 2004.                   110(a) for other subsections.
MCAQD Rule 310.01 ``Fugitive Dust From   110(a).
 Open Areas, Vacant Lots, Unpaved
 Parking Lots, and Unpaved Roadways'',
 adopted February 17, 2005.
MCAQD Appendix C ``Fugitive Dust Test    189(b), and 188(e) for
 Methods'', adopted April 7, 2004.        subsection 3.3.2. 110(a) for
                                          other subsections.
MCAQD Appendix F ``Soil Designations'',  189(b) and 188(e).
 adopted April 7, 2004.
MCAQD ``Application for Dust Control     189(b) and 188(e) for Section
 Permit'', adopted July 1, 2005.          2, subsections 10 and 11, and
                                          Section 3, subsection I.
                                          110(a) for other subsections.
MCAQD ``Guidance for Application for     189(b) and 188(e) for Section
 Dust Control Permit'', adopted July 1,   2, subsection 13, and Section
 2005.                                    3. 110(a) for other
                                          subsections.
Maricopa County Board Resolution No. C-  189(b) for enforcement resource
 85-05-005-0-00, adopted January 19,      provisions of Measures 1
 2005.                                    through 4. 110(a) for other
                                          provisions, including Measure
                                          5.
City of Phoenix Resolution No. 20114,    110(a).
 adopted June 16, 2004.
Resolutions from 18 municipalities and   110(a).
 the Arizona Department of
 Transportation, adopted on various
 dates.
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    We approved versions of MCAQD Rules 310, 310.01 and Appendix C into 
the SIP on July 25, 2002 and MCAQD Rule 316 on January 4, 2001. 67 FR 
48717 and 66 FR 730.
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    \3\ Maricopa County Air Quality Department (MCAQD) Rule 310.01, 
``Application for Dust Control Permit,'' and ``Guidance for 
Application for Dust Control Permit'' can be found in the Salt River 
plan supplement while the remaining rules and commitments can be 
found in Appendix B of the Salt River plan.
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B. Completeness of the SIP Submittal

    CAA section 110(k)(1)(B) requires us to determine if a SIP 
submittal is complete within 60 days of its receipt. This completeness 
review allows us to quickly determine if the submittal includes all the 
necessary items and information we need to take action on it. We make 
completeness determinations using criteria we have established in 40 
CFR part 51, Appendix V.
    We have reviewed the October 7, 2005 and November 29, 2005 
submittals from Arizona and affirmatively determined that they satisfy 
our completeness criteria and that they are thereby complete for the 
purposes of section 110(k)(1) of the Act. We notified the State of our 
completeness determination by a letter to ADEQ dated December 8, 2005.

II. Applicable CAA Requirements

A. Best Available Control Measures (BACM) and Most Stringent Measures 
(MSM)

    CAA section 189(b)(1)(B) requires serious area PM-10 plans to 
provide for the implementation of BACM, including Best Available 
Control Technology (BACT), within four years of reclassification to 
serious. For the Phoenix area this date was June 10, 2000.\4\ Since 
that date has passed, BACM must now be implemented as expeditiously as 
practicable. See Delaney v. EPA, 898 F.2d 687 (9th Cir. 1990); 55 FR 
41204, 41210 (October 1, 1990); and 63 FR 28898, 28900 (May 27, 1998).
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    \4\ The Phoenix area's reclassification to serious was effective 
on June 10, 1996. 61 FR 21372 (May 10, 1996).
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    We have issued a General Preamble, 57 FR 13498 (April 16, 1992) and 
57 FR 18070 (April 28, 1992), and Addendum to the General Preamble 
(Addendum), 59 FR 41998 (August 16, 1994), describing our preliminary 
views on how we intend to review SIPs submitted to meet the Clean Air 
Act's requirements for PM-10 plans. The General Preamble mainly 
addresses the requirements for moderate areas and the Addendum, the 
requirements for serious areas.
    In the Addendum, we explain that BACM is required for all source 
categories in serious areas unless the state adequately demonstrates 
that a particular source category does not contribute significantly to 
nonattainment of the PM-10 standards. We have established a presumption 
that a ``significant'' source category is one that contributes 5 [mu]g/
m3 or more of PM-10 to a location of 24-hour violation. 
Addendum at 42011. We have defined BACM to be, among other things, the 
maximum degree of emission reduction achievable from a source or source 
category which is determined on a case-by-case basis, considering 
energy, economic, environmental impacts and other costs. BACT applies 
to stationary sources and is a subset of BACM. Addendum at 42009.
    We have outlined in our guidance a multi-step process for 
identifying BACM/BACT. Addendum at 42010-42014. The steps are:
    1. Develop a detailed emissions inventory of PM-10 sources and 
source categories,
    2. Model to evaluate the impact on PM-10 concentrations over the 
standards of the various sources and source categories to determine 
which are significant,
    3. Identify potential BACM for significant source categories and 
evaluate their reasonableness, considering technological feasibility, 
costs, and energy and environmental impacts and,
    4. Provide for the implementation of the BACM or provide a reasoned 
justification for rejecting any potential BACM. When the process is 
complete, the individual measures should then be converted into a 
legally enforceable vehicle (e.g., a regulation or permit). CAA 
sections 172(6) and 110(a)(2)(A).
    Under CAA section 188(e), the State is required to demonstrate to 
our satisfaction that its serious area plan includes the most stringent 
measures that are included in the implementation plan of any state or 
are achieved in practice in any state and can be feasibly implemented 
in the area. The section 188(e) requirement for MSM is similar to the 
requirement for BACM and we have therefore defined a ``most stringent

[[Page 39254]]

measure'' level of control as the maximum degree of emission reduction 
that has been required or achieved from a source or source category in 
other SIPs or in practice in other states and can be feasibly 
implemented in the area. Given this similarity between the BACM and MSM 
requirements, we believe that determining MSM should follow a process 
similar to determining BACM, but with one additional step, to compare 
the potentially most stringent measure against the measures already 
adopted in the area to determine if the existing measures are most 
stringent. See, e.g., 66 FR 50252, 50257 and 50282-50284 (October 2, 
2001).

B. General SIP Requirements

    Generally, SIP rules must be enforceable (see CAA section 110(a)) 
and must not relax existing requirements (see sections 110(l) and 
193).\5\ The EPA guidance and policy document we used to help evaluate 
enforceability is ``Guidance Document for Correcting Common VOC and 
Other Rule Deficiencies'', U.S. EPA Region IX, August 21, 2001 (the 
Little Bluebook).
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    \5\ CAA section 110(l) prohibits us from approving a revision to 
the applicable implementation plan if that revision would interfere 
with any applicable requirement of the Act. CAA section 193 
prohibits us under certain circumstances from approving a revision 
to the applicable implementation plan unless the modification 
insures equivalent or greater emissions reductions.
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III. Evaluation of Adopted Measures and Commitments

A. Summary

    The measures in the Salt River plan consist of: (1) Rules adopted 
by MCAQD for various fugitive dust sources; (2) MCAQD commitments 
designed to improve source compliance with fugitive dust requirements; 
(3) commitments from multiple municipalities, Maricopa County 
Department of Transportation (MCDOT), and the State addressing paved 
road re-entrained dust; (4) a City of Phoenix commitment addressing 
alluvial channels; and (5) MCAQD application and guidance documents for 
Rule 310 dust control plans.

B. Rules 316 and 325

    ADEQ identifies industrial sources as significant contributors to 
PM-10 24-hour exceedences at the Salt River monitors.\6\ Industrial-
related emissions fall into three categories: (1) Stationary point 
(stack) sources; (2) stationary process sources (e.g., aggregate 
screens and crushers); and (3) area sources, e.g., unpaved roads, open 
storage piles, and trackout onto paved roads. Given ADEQ's finding that 
industrial sources contribute significantly to 24-hour PM-10 
exceedences, CAA sections 189(b) and 188(e) apply and BACM and MSM 
demonstrations are required.
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    \6\ Based on an emissions inventory and modeling for the Salt 
River area, ADEQ estimates that industrial sources contributed 
approximately 26 percent to 2002 average low-wind day exceedences 
(with a highest contribution of 60 [mu]g/m3 at a single 
monitor) and 16 percent to 2002 exceedences on days with wind speeds 
over 15 miles per hour (with a highest contribution of 58 [mu]g/
m3 at a single monitor). Salt River plan, Table 4.2.1, 
and Salt River TSD, Table 6-8. This estimate excludes industrial 
source trackout which is quantified in the paved road re-entrained 
dust source category.
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    ADEQ found that the vast majority of industrial source PM-10 
emissions are generated by nonmetallic mineral processing sources. The 
SIP-approved version of MCAQD Rule 316 contains requirements for 
stationary stack and process sources at nonmetallic mineral processing 
plants and rock product plants.\7\ With regard to other industrial 
sources in the Salt River area, ADEQ evaluated permitted industrial 
stack sources for compliance with BACM/BACT and MSM and found that 
control measures on all facilities met these requirements except brick 
and structural clay product manufacturing facilities.\8\ Thus, MCAQD 
adopted Rule 325 based on ADEQ's recommendation that BACM/BACT and MSM 
must be met for these sources.\9\
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    \7\ EPA approved a version of Rule 316 adopted on April 21, 
1999. 66 FR 730 (January 4, 2001). We were not required to evaluate 
the rule for BACT because the sources to which it applied were not 
deemed significant at the time. We did, however, determine that the 
rule met the CAA requirements for Reasonably Available Control 
Technology (RACT). See 65 FR 42649, 42651 (July 11, 2000).
    \8\ Salt River plan, pg. 70.
    \9\ Rule 325 only applies to stationary sources, as opposed to 
area sources. Area sources located at facilities subject to Rule 325 
are subject to Rule 310 fugitive dust requirements.
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    ADEQ first identified candidate BACM/BACT and MSM for Rule 316 and 
Rule 325 sources by researching controls in several areas, including 
PM-10 nonattainment areas in California, Nevada, Texas, Florida, and 
Oklahoma.\10\ ADEQ then conducted a technical and economic feasibility 
analysis with specific estimates of control efficiency and cost for 
each type of emissions point or control measure.\11\ For the MSM 
comparison, ADEQ developed a series of tables that benchmark the most 
stringent controls in other areas.\12\
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    \10\ Salt River plan, Appendix C.
    \11\ Salt River plan, Chapter 4, section 4.3.4.
    \12\ Ibid., Tables 4.3.4.7 through 4.3.4.12.
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    Based on its analysis, ADEQ recommended specific augmentations to 
Rule 316 for purposes of meeting BACM/BACT and MSM requirements. In 
addition, through its rulemaking process for Rule 316,\13\ MCAQD 
identified additional MSM for nonmetallic mineral processing facilities 
in South Coast Air Quality Management District (SCAQMD) Rule 1157, 
``PM-10 Emissions from Aggregate and Related Operations,'' adopted on 
January 7, 2005. Finally, ADEQ recommended enhanced enforcement of Rule 
316 but did not specify how it was to be achieved.\14\
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    \13\ Ibid., Appendix B, Revision to Maricopa County Rule 316 
Nonmetallic Mineral and Processing, Appendix 2, ``Notice of Final 
Rulemaking, Maricopa County Air Pollution Regulations, Regulation 
III, Rule 316--Nonmetallic Mineral Processing''.
    \14\ Salt River plan, pgs. 56 and 78.
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1. Rule Revisions and New Rule
    In revising Rule 316, MCAQD expanded the rule's coverage to include 
area sources \15\ and incorporated additional control measures based on 
ADEQ's recommendations as well as requirements contained in SCAQMD Rule 
1157. As adopted on June 8, 2005, the rule includes the following 
requirements for nonmetallic mineral processing sources: Opacity 
standards ranging from 7% to 20% for various nonmetallic mineral 
processes; venting of stack emissions to a properly sized fabric filter 
baghouse and compliance with 7% opacity; enclosure on the sides of all 
shaker screens; and a permanently mounted watering system for crushing 
and screening inlets and outlets. Additional specific controls and 
performance standards apply to asphaltic concrete plants and concrete 
plants and/or bagging operations. With respect to area sources located 
at nonmetallic mineral processing facilities, Rule 316 requires 
specific work practice and performance standards for unpaved roads, 
unpaved parking/staging areas, open storage piles and active material 
handling, trackout onto paved public access roads,

[[Page 39255]]

cleaning of internal paved roads, and bulk material hauling/
transporting.
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    \15\ Historically, Rule 316 has contained only emission 
limitations and not fugitive dust control measures specific to area 
sources located at nonmetallic mineral processing plants and rock 
processing plants. Facilities subject to Rule 316 have been required 
to comply with fugitive dust control measures in Rule 310. MCAQD 
revisions to Rule 316 include control measures specific to fugitive 
dust sources at these facilities. Sources subject to specific 
control measures in Rule 316 are no longer subject to Rule 310 while 
sources not subject to specific Rule 316 control measures are still 
subject to Rule 310. EPA approved Rule 310, which covers certain 
industrial area sources, as meeting the CAA's BACM and MSM 
requirements. 67 FR 48718, 48739. However, new information in the 
Salt River plan demonstrates a relatively large contribution of 
industrial area sources to Salt River PM-10 exceedences which 
warrants an updated BACM/BACT and MSM demonstration for all such 
sources.
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    As adopted on August 10, 2005, new Rule 325 includes the following 
requirements for brick and structural clay product manufacturing 
sources: A 20% opacity standard; a limit of 0.42 lbs of particulate 
matter per ton of fired product from existing tunnel kilns with a 
capacity of > 1 ton per hour throughput and new or reconstructed tunnel 
kilns with a capacity of <  10 tons per hour throughput; and a limit of 
0.12 lbs of particulate matter per ton of fired product from new or 
reconstructed tunnel kilns with a capacity of >= 10 tons per hour 
throughput.
    We have evaluated Rule 316 and Rule 325 requirements to determine 
whether they represent BACM/BACT and MSM. As part of this evaluation, 
we considered ADEQ's BACM/BACT and MSM analysis and associated 
recommended control measures, along with reasoned justifications for 
measures not recommended.\16\ We compared ADEQ's recommended measures 
against the actual measures adopted into Rule 316 and Rule 325. In 
addition, we compared Rule 316 requirements to those adopted in SCAQMD 
Rule 1157 and compared Rule 325 requirements to EPA's New Source 
Performance Standards for clay manufacturing kilns.\17\
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    \16\ Op. Cit., Tables 4.3.4.7 through 4.3.4.13 and accompanying 
text.
    \17\ 40 CFR 63.8555(a), subpart KKKKK, table 1 and 40 CFR 
63.8405(a), subpart JJJJ, table 1.
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    With respect to BACM/BACT, we found that Rule 316 and Rule 325 meet 
BACT requirements for stationary sources. We also found that the Rule 
316 requirements satisfy BACM for area sources and are equally or more 
stringent relative to the Rule 310 requirements we have approved as 
BACM. With respect to MSM, we found that Rule 316 and Rule 325 measures 
are equally or more stringent relative to similar adopted requirements 
in rules applicable in other PM-10 nonattainment areas. We also found 
Rule 316 and Rule 325 requirements to be consistent with our 
enforceability criteria.
    As noted above, the CAA requires BACM/BACT to be implemented as 
expeditiously as practicable. Most of the requirements in Rule 316 were 
effective as of the June 8, 2005 adoption date and all of the 
requirements are currently applicable. With respect to Rule 325, 
compliance with the rule is not required until December 31, 2006. MCAQD 
provided adequate justification for this implementation date based on 
substantial annualized capital investment costs required of facilities 
subject to the rule for the purchase of necessary emissions control 
equipment.
2. Enforcement Resources and Methods
    The basic elements of MCAQD's enforcement program include permit 
review, facility inspections, source testing of equipment, and review 
of records and activities. MCAQD's enforcement options include orders 
of abatement, civil actions for injunctive relief or civil penalties, 
and class 1 misdemeanor citations.\18\
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    \18\ Ibid., Maricopa County Board Resolution No. C-85-05-005-0-
00, Measures 2 and 4.
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    In addressing ADEQ's recommendation for enhanced Rule 316 
enforcement, MCAQD committed to increase the inspection frequency for 
Rule 316 sources from once every two years to four times per year 
beginning on July 1, 2005.\19\ We consider enforcement resources to be 
part of the CAA section 189(b) requirement that serious area PM-10 
plans include provisions to assure the implementation of BACM. MCAQD 
conducted a workload analysis for the increased Rule 316 inspection 
frequency based on the number of permitted sources in fiscal year 2004 
and determined that one additional inspector and an additional 
supervisor are needed.\20\ This would increase the number of MCAQD 
inspectors dedicated to non-Title V and general permitted stationary 
sources, which includes Rule 316 and Rule 325 sources, from seven to 
eight. In evaluating the level of enforcement resources dedicated to 
Rule 316 and Rule 325, we consider the number of MCAQD permits 
associated with facilities subject to these rules. MCAQD issued 107 
permits for Rule 316 sources in 2004. Rule 325 applies to two brick and 
clay structural facilities and one tunnel kiln.\21\
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    \19\ Salt River TSD, Appendix D, Maricopa County Board 
Resolution No. C-85-05-005-0-00, Measure 2.
    \20\ ``Workload Analysis for Rule 316 Permitted Sources'' is 
included in the docket associated with this proposed rule. This 
analysis specifies that the four annual inspections will consist of 
one full inspection and three partial inspections. A partial 
inspection involves checking compliance with fugitive dust controls 
but not necessarily process equipment unless an obvious problem is 
observed.
    \21\ Salt River plan, Appendix B, Notice of Final Rulemaking, 
Rule 325, August 10, 2005, pg. 3450.
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3. Conclusion
    In evaluating MCAQD Rules 316 and 325, we have found that they meet 
the BACM/BACT and MSM requirements of CAA sections 189(b)(1)(B) and 
188(e), respectively, and that MCAQD enforcement resources are adequate 
to provide for the implementation of BACM. We have also found these 
rules to be consistent with our policy and guidance regarding 
enforceability and SIP relaxations. Because we believe that Rule 316 
and Rule 325 fulfill all relevant requirements, we propose to approve 
them and the Maricopa County Board Resolution No. C-85-05-005-0-00 \22\ 
under CAA section 110(k)(3) as meeting the requirements of CAA sections 
189(b)(1)(B) and 188(e). Our detailed analysis of Rule 316 and Rule 325 
requirements can be found in the TSD associated with this proposed 
rule.
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    \22\ Measures 2 and 4 of the Maricopa County Board Resolution 
are relevant to Rule 316 and Rule 325 sources, respectively.
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C. Rules 310 and 310.01 and Related Submittals

    ADEQ identifies construction sources, vacant lots, and 
miscellaneous disturbed areas as significant contributors to PM-10 24-
hour exceedences at the Salt River monitors.\23\ Rule 310 applies to 
dust generating operations including construction/earthmoving and 
demolition sites. Rule 310.01 applies to vacant lots and miscellaneous 
disturbed areas, among other sources, which are not subject to Rule 
310. Performance standards and test methods for opacity and surface 
stabilization for Rule 310 and Rule 310.01 sources are found in 
Appendix C ``Fugitive Dust Test Methods'' of MCAQD Regulation III. Rule 
310 also requires construction site owners/operators to develop dust 
control plans subject to MCAQD approval. MCAQD's ``Application for Dust 
Control Permit'' and ``Guidance for Application for Dust Control 
Permit'' provide supplemental information on MCAQD's implementation of 
the Rule 310 dust control plan requirements.\24\
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    \23\ Based on an emissions inventory and modeling for the Salt 
River area, ADEQ estimates that construction sources contributed 5.8 
percent to 2002 average low-wind day exceedences and 4.4 percent to 
2002 exceedences on days with wind speeds over 15 miles per hour 
(with a highest contribution of 18 [mu]g/m3 at a single 
monitor). These estimates exclude construction-related trackout 
which is quantified in the paved road re-entrained dust source 
category. ADEQ estimates that vacant lots and miscellaneous 
disturbed areas contributed approximately 26 percent to 2002 
exceedences on days with wind speeds over 15 miles per hour (with a 
highest contribution of 52 [mu]g/m3 at a single monitor). 
Salt River plan, Table 4.2.1, and Salt River TSD, Table 6-8.
    \24\ On July 25, 2002, we approved Rule 310, Rule 310.01 and 
Appendix C ``Fugitive Dust Test Methods'' of MCAQD Regulation III as 
meeting the CAA's BACM and MSM requirements.
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    Upon assessing the contribution of construction sites, vacant lots, 
and miscellaneous disturbed areas to Salt River exceedences, ADEQ 
identified a critical need for additional inspectors to enforce Rule 
310 and Rule 310.01

[[Page 39256]]

requirements.\25\ EPA last evaluated enforcement resources for Rule 310 
and Rule 310.01 sources in 2001.\26\ We agree with ADEQ's assessment 
that the continuing significant contribution of these sources to PM-10 
exceedences in the Salt River area (and other sites in the Phoenix PM-
10 nonattainment area with similar sources) warrants an updated 
evaluation of enforcement resources designed to ensure compliance with 
Rule 310 and Rule 310.01 requirements.
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    \25\ Salt River plan, pg. 29.
    \26\ 66 FR 50252, 50271-50273.
---------------------------------------------------------------------------

    ADEQ did not identify a need for revisions to the requirements of 
Rule 310 and Rule 310.01 \27\ beyond fulfilling three MCAQD commitments 
associated with EPA's BACM and MSM approval for construction 
sources.\28\ These commitments include (1) adding a modified opacity 
standard/test method to Appendix C tailored to non-process fugitive 
dust sources that create intermittent plumes; (2) incorporating 
additional requirements for dust suppression practices/equipment into 
dust control plans and/or Rule 310; \29\ and (3) revising and 
distributing the sample daily recordkeeping logs for Rule 310 sources 
to be consistent with rule revisions and to provide sufficient detail 
documenting dust control measure implementation.
---------------------------------------------------------------------------

    \27\ One exception is that ADEQ recommended wind breaks as an 
additional control measure for Rule 310.01 in conjunction with 
existing measures requiring surface stabilization. We consider this 
optional but not necessary to meet BACM because the rule relies on 
surface stabilization standards to demonstrate compliance and the 
emissions reduction potential of wind breaks is less certain. Also, 
wind breaks are not economically feasible in all circumstances.
    \28\ 66 FR 50252, 50256-50257. The commitments are contained in 
the MAG plan approved by EPA. See footnote 1.
    \29\ MCAQD also committed to raise awareness of on-site 
supervisors of dust control plans through contact during inspections 
and a revised training curriculum.
---------------------------------------------------------------------------

1. Rule Revisions and New Rule
    In addressing the BACM and MSM commitments for construction sources 
in the MAG plan, MCAQD adopted Appendix F of Regulation III on April 7, 
2004, revised subsection 3.3.2 of Appendix C of Regulation III and 
subsections 304.5 and 502 of Rule 310 on April 7, 2004, and revised the 
Application for Dust Control Permit and the Guidance for Application 
for Dust Control Permit on July 1, 2005. We have evaluated these 
submittals for consistency with the BACM and MSM commitments we 
approved in the MAG plan and our general requirements in CAA section 
110.
    MCAQD also strengthened and clarified certain requirements in Rule 
310 and Appendix C (adopted on April 7, 2004) and in Rule 310.01 
(adopted on February 17, 2005). We have evaluated these revisions for 
consistency with our general requirements in CAA section 110.
    Specific MCAQD revisions intended to fulfill the three MAG plan 
commitments are as follows: In order to meet the commitment concerning 
Appendix C, MCAQD adopted an opacity test method into Appendix C that 
is tailored to address intermittent plumes from non-process fugitive 
dust sources at construction sites.\30\ With respect to the commitment 
to incorporate additional dust suppression practices/equipment into 
dust control plans and/or Rule 310, MCAQD: (a) Adopted Appendix F which 
classifies soils into four types based on their PM-10 emissions 
potential and contains a map delineating the locations in the Phoenix 
PM-10 nonattainment area of these soil types; (b) revised Rule 310, 
subsection 304.5, to require that dust control plans disclose which of 
the four designated soil types described in Appendix F (or as measured 
at a particular site) is naturally present at or will be imported to 
the dust generating operation; and (c) added minimum criteria in the 
Application for Dust Control Permit and Guidance for Application for 
Dust Control Permit for the amount of water that needs to be available 
(i.e., water supply in conjunction with water application system) for 
sites with soils classified in Appendix F as ``moderate'' or 
``severe''.\31\ These criteria apply to individual permits subject to 
review and approval by MCAQD.\32\ Finally, to meet the commitment 
concerning recordkeeping requirements, MCAQD revised subsection 502 of 
Rule 310 to include examples of dust suppression activities for which 
recordkeeping is required. MCAQD also revised its sample daily 
recordkeeping logs which are available on MCAQD's Web site to provide 
various formats for documenting application of measures for specific 
types of dust generating sources.
---------------------------------------------------------------------------

    \30\ Appendix C, section 3.3.2.
    \31\ The criteria apply where water is not combined with a 
chemical or organic dust suppressant.
    \32\ We also note that MCAQD addressed its commitment to raise 
awareness of on-site supervisors of dust control plans by providing 
an online construction guide and instructing its inspectors to 
review dust control plans with construction site personnel upon 
initial and subsequent inspections.
---------------------------------------------------------------------------

    Other MCAQD revisions to Rule 310, Rule 310.01, and Appendix C 
consist of strengthenings and clarifications of existing SIP-approved 
requirements.\33\
---------------------------------------------------------------------------

    \33\ See EPA's TSD associated with this proposed action, section 
D.3.b.
---------------------------------------------------------------------------

    Our detailed evaluation of these submittals can be found in the TSD 
associated with this proposed rule.
2. Enforcement Resources and Methods
    With respect to enforcement resources dedicated to inspecting 
sources subject to Rule 310 and Rule 310.01, MCAQD conducted a 2005/06 
workload analysis of its earthmoving and vacant lot programs and also 
created an inspection priority plan for Rule 310.01 sources.\34\ 
Maricopa County Board Resolution No. C-85-05-005-0-00,\35\ adopted on 
January 19, 2005, commits MCAQD to increase the number of inspectors 
dedicated to Rule 310 and Rule 310.01 enforcement, along with other 
measures designed to improve source compliance. Specifically, the 
Maricopa County Board Resolution No. C-85-05-005-0-00 commitments 
include:
---------------------------------------------------------------------------

    \34\ Salt River plan, Appendix F, Enclosures 1 and 2.
    \35\ Salt River plan, Appendix D.
---------------------------------------------------------------------------

    (a) Hire ten additional inspectors to enforce MCAQD Rule 310.01 by 
August 2005; \36\
---------------------------------------------------------------------------

    \36\ As of April 2006, MCAQD had hired all ten of the Rule 
310.01 inspectors.
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    (b) Develop and submit to EPA by March 2005 an inspection priority 
plan for vacant lots/open areas and unpaved parking lots in the PM-10 
nonattainment area; \37\
---------------------------------------------------------------------------

    \37\ MCAQD developed an inspection priority plan that is 
included in the Salt River plan.
---------------------------------------------------------------------------

    (c) Conduct inspections on all vacant lots/open areas, including 
alluvial channels,\38\ in the Salt River area by October 2006 with 
periodic follow-up inspections;
---------------------------------------------------------------------------

    \38\ Alluvial channels in the Salt River area consist of a dry 
riverbed subject to Rule 310.01.
---------------------------------------------------------------------------

    (d) Hire an additional twelve inspectors, four supervisors, and 
three support staff by June 2005 to work proactively and directly on 
compliance and enforcement of the Rule 310 earthmoving fugitive dust 
program; \39\ and
---------------------------------------------------------------------------

    \39\ As of October 2005, MCAQD had hired all twelve of the 
additional Rule 310 inspectors, the four supervisors, and two of the 
support staff. MCAQD expects to hire the third support staff 
shortly. The support staff position does not affect field 
enforcement efforts.
---------------------------------------------------------------------------

    (e) Complete a user fee analysis and have new fees considered by 
the Board of Supervisors in January 2005 to be effective no later than 
July 1, 2005, to permanently fund the nineteen Rule 310 positions.\40\
---------------------------------------------------------------------------

    \40\ This commitment has been met through MCAQD's adoption of a 
revised Rule 280 ``Fees'' on May 18, 2005, with an effective date of 
July 1, 2005.
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    In reviewing the adequacy of these commitments, we compare them to

[[Page 39257]]

enforcement provisions in the currently applicable Phoenix PM-10 
SIP.\41\ The MAG plan provides for eight fugitive dust inspectors to 
implement MCAQD's fugitive dust rules. Because the January 2005 
Maricopa County Board Resolution provides for an additional twenty-two 
inspectors to implement MCAQD's fugitive dust rules, this represents a 
significant increase in personnel resources. The number of additional 
inspectors needed is based on MCAQD's projected fiscal year 2005/06 
workload analysis for its earthmoving and vacant lot programs which 
accounts for the number of vacant parcels in the Phoenix area and the 
number of Rule 310 permits, which have increased since 2000.\42\
---------------------------------------------------------------------------

    \41\ MAG plan, Commitments for Implementation, Volume Four, 
Maricopa County, Fourth Submittal, Exhibit A, Revised Measure 6 of 
Resolution No. C 88-00-017-6-A2128, adopted December 15, 1999.
    \42\ MCAQD was responsible for the issuance of 2,500 earthmoving 
permits in 2000 (Salt River plan, pg. 29), which have increased to 
4,548 permits projected for fiscal year 2005/06 according to MCAQD's 
workload analysis. The workload analysis staffing conclusions are 
based on accommodating 9,152 inspections per year of Rule 310 
sources and 4,587 inspections per year of Rule 310.01 sources.
---------------------------------------------------------------------------

    MCAQD's inspection priority plan for vacant lots/open areas and 
unpaved parking lots provides for identification of these sources 
through complaint investigations, field observations, soil maps, the 
Maricopa County Assessor Geographic Information Systems Web site, and/
or aerial photographs. The plan provides for site inspections to be 
prioritized based on complaint investigations, location within the Salt 
River area, soil texture potential for wind erosion, size (lots in 
excess of 10 acres), location within the PM-10 nonattainment area, and 
location in proximity to sensitive receptors (e.g., schools).\43\ The 
inspection priority plan also provides for an inspection rotation/re-
inspection electronic database to rate the dust generating potential of 
vacant lots/open areas based on criteria such as lot size and 
compliance history to assist in the scheduling and prioritizing of 
sites for re-inspection. The inspection priority plan is currently in 
effect.
---------------------------------------------------------------------------

    \43\ We note that lots less than ten acres or that are otherwise 
not prioritized in MCAQD's inspection priority plan are still 
subject to proactive inspections. However these lots will receive a 
lower priority than those meeting the plan's criteria.
---------------------------------------------------------------------------

    The MAG plan does not contain specific criteria for prioritizing 
vacant lot/open area and unpaved parking lot inspections. Thus, the 
MCAQD inspection priority plan for these sources would strengthen the 
SIP.
    We described the basic elements of MCAQD's enforcement program in 
section III.B.2 of this proposed rule.
3. Conclusion
    We have found that the January 2005 Maricopa County Board 
Resolution enforcement resource commitments for Rule 310 and Rule 
310.01 adequately provide for the implementation of the BACM 
requirements in those rules by substantially increasing the number of 
inspectors and associated personnel for enforcing fugitive dust 
requirements. We have found that other enforcement-related commitments 
would strengthen the SIP.
    We have reviewed the MCAQD submittals that address the three 
commitments in the approved MAG plan for construction sources \44\ and 
have found that they are consistent with the BACM and MSM requirements 
of CAA sections 189(b)(1)(B) and 188(e), respectively, and also are 
consistent with our policy and guidance regarding enforceability and 
SIP relaxations. Finally, we have determined that other revisions to 
Rule 310 and Rule 310.01 and would strengthen the SIP and are 
consistent with our policy and guidance regarding enforceability and 
SIP relaxations.
---------------------------------------------------------------------------

    \44\ These include revisions to Rule 310 (subsections 304.5 and 
502), Appendix C, Application for Dust Control Permit, Guidance for 
Application for Dust Control Permit, and the newly submitted 
Appendix F.
---------------------------------------------------------------------------

    Therefore, we propose to approve Rule 310, Rule 310.01, Maricopa 
County Board Resolution No. C-85-05-005-0-00,\45\ Appendix C, Appendix 
F, ``Application for Dust Control Permit'', and ``Guidance for 
Application for Dust Control Permit'' under CAA section 110(k)(3). We 
propose to approve sections 304.5 and 502 of Rule 310, section 3.3.2 of 
Appendix C, Appendix F, and the enforcement resource provisions of 
Measures 1 and 3 of Resolution C-85-05-005-0-00 as meeting the BACM and 
MSM requirements of sections 189(b)(1)(B) and 188(e). We propose to 
approve Section 2, subsections 10 and 11, and Section 3, subsection I 
of the Application for Dust Control Permit as meeting the BACM and MSM 
requirements of sections 189(b)(1)(B) and 188(e). We propose to approve 
Section 2, subsection 13, and Section 3 of the Guidance for Application 
for Dust Control Permit as meeting the BACM and MSM requirements of 
sections 189(b)(1)(B) and 188(e). We propose to approve all other 
revisions to these rules, Resolution, Application for Dust Control 
Permit and Guidance for Application for Dust Control Permit as SIP 
strengthenings.
---------------------------------------------------------------------------

    \45\ Measures 1 and 3 of the Maricopa County Board Resolution 
are relevant to Rule 310.01 and Rule 310 sources, respectively.
---------------------------------------------------------------------------

D. City of Phoenix Alluvial Channels Commitment

    The Salt River area contains dry river channels comprised of 
alluvial soils. ADEQ assessed the PM-10 impact of alluvial channels in 
the Salt River area, and found that they contribute significantly to 
wind-driven exceedences.\46\ In assessing the wind erosion potential of 
alluvial channel soils, ADEQ found that some soils have particularly 
high-emitting potential relative to average vacant land soils. The City 
of Phoenix owns a substantial amount of alluvial channel land in the 
Salt River area.
---------------------------------------------------------------------------

    \46\ Salt River plan, Table 4.2.1. ADEQ estimates that alluvial 
channels contributed approximately 15 percent to 2002 average 
exceedences on days with wind speeds over 15 miles per hour (with a 
highest contribution of 80 [mu]g/m3 at a single monitor).
---------------------------------------------------------------------------

    Alluvial channels are subject to MCAQD Rule 310.01 requirements. 
ADEQ's recommended approach to addressing alluvial channels throughout 
the nonattainment area is the same as that for vacant lots/open areas 
and miscellaneous disturbed surfaces, which is increasing enforcement 
of Rule 310.01 requirements through the hiring of additional MCAQD 
inspectors.\47\ We have addressed this measure in section III.C.2 of 
this proposed rule.
---------------------------------------------------------------------------

    \47\ Salt River plan, pgs. 32 and 41.
---------------------------------------------------------------------------

    ADEQ notes that one of the most effective control methods that can 
be applied to alluvial channels is establishing barriers to prevent 
vehicle trespass in combination with stabilization of soils. In order 
to maximize compliance with Rule 310.01 requirements on its alluvial 
channel land, the City of Phoenix adopted Resolution No. 20114 on June 
16, 2004, which outlines a plan for dust control measures on alluvial 
channels in the Salt River area.\48\ Specifically, the City of Phoenix 
committed to ``develop and implement a program to control vehicle 
trespass on City-owned vacant land to address particulate emissions and 
criminal activity. These lands may include dry river beds, washes, and 
other open areas where significant trespass occurs. Measures to reduce 
trespass may include signs, increased police enforcement, such as 
barriers, fences, berms or other measures. Measures may include 
stabilization of disturbed soils where feasible.'' The City of Phoenix 
budgeted $200,000 in fiscal year 2005/06 to implement this measure. The 
Salt River plan contains a 2004 milestone progress report which

[[Page 39258]]

specifies City of Phoenix actions to prevent trespass and stabilize 
soils on City-owned alluvial channel lands.\49\
---------------------------------------------------------------------------

    \48\ Ibid., Appendix D, City of Phoenix Resolution No. 20114, 
Measure 04-DC-3.
    \49\ Salt River plan, Appendix E, Table 3. Concentrated 
enforcement efforts on alluvial channels in the Salt River area from 
July through November 2004 resulted in fifty-five citations and 220 
warnings. Vehicle trespass dropped to zero to two vehicles in 
December and pedestrian trespassers dropped from forty-five to eight 
per weekend. Thirty ``no trespass'' signs were installed and 
maintained. Three-hundred and thirty tons of trash and over 2,000 
tires were removed by contractors from the upper riverbank and a 
thick layer of mulch was applied to twelve acres. Contractors have 
secured 1,800 feet of fences and berms to prevent trespass along 
Broadway Road since July 2004. The City treated the entire length of 
berm on its property with polymer stabilizer. One-thousand, one-
hundred feet of guardrail on West side of 35th Avenue have been 
installed. Installation of concrete barriers at all four corners of 
the 51st Avenue bridge began in January 2005. Rains in January 2005 
formed a crust in the alluvial channel.
---------------------------------------------------------------------------

    Because we believe the City of Phoenix Resolution No. 20114, 
Measure 04-DC-3, strengthens the SIP and is consistent with our policy 
and guidance regarding enforceability and SIP relaxations, we propose 
to approve it under CAA section 110(k)(3) as a SIP strengthening.

E. Municipality, County, and State Paved Road Re-Entrained Dust 
Commitments

    ADEQ identifies paved road re-entrained dust as a significant 
contributor to PM-10 24-hour exceedences at the Salt River 
monitors.\50\ In evaluating sources responsible for paved road dust 
emissions in the Salt River area, ADEQ found the most significant 
sources of dust loading on paved roads to be from windblown emissions, 
soil trackout, and emissions from earthmoving and other dust generating 
processes in areas of high industrial, construction, and agricultural 
activity.\51\ In order to address the largest sources of the problem, 
ADEQ recommended enhanced enforcement of Rule 310 and Rule 316 and the 
adoption of specific Rule 316 requirements for control of trackout.\52\ 
We have addressed these recommendations in sections III.B.2 and C.2 of 
this proposed rule.
---------------------------------------------------------------------------

    \50\ Salt River plan, Table 4.2.1. ADEQ estimates that paved 
road re-entrained dust contributed approximately 64 percent to 2002 
average low-wind day exceedences (with a highest concentration of 74 
[mu]g/m3 at a single monitor) and 13.5 percent to 2002 
average exceedences on days with wind speeds over 15 miles per hour 
(with a highest concentration of 43 [mu]g/m3 at a single 
monitor).
    \51\ Salt River plan, pg. 72.
    \52\ Ibid., pg. 78.
---------------------------------------------------------------------------

    ADEQ also recommended enhanced street sweeping with PM-10 efficient 
sweepers of paved road segments that typically experience a high level 
of soil and dust deposition,\53\ e.g., in locations with high 
industrial, construction, and agricultural activity.\54\
---------------------------------------------------------------------------

    \53\ Ibid., pg. 79.
    \54\ EPA approved a variety of paved road re-entrained dust 
measures on July 25, 2002 as meeting the CAA's BACM and MSM 
requirements, including city, County, and State resolutions 
addressing street sweeping. The SIP-approved MAG plan does not 
contain measures for targeted street sweeping, using PM-10 efficient 
street sweepers, on road segments identified as having particularly 
high emissions potential.
---------------------------------------------------------------------------

    Eighteen municipalities in the Phoenix PM-10 nonattainment area, 
Maricopa County Department of Transportation and the Arizona Department 
of Transportation adopted resolutions \55\ in 2004 and 2005 that 
address the purchase/use of additional PM-10 efficient street sweepers 
and more frequent, targeted street sweeping. These resolutions largely 
reflect a model protocol developed by MAG containing the following four 
elements: Targeting ``high dust'' arterials and collectors and 
increasing sweeping frequencies with PM-10 efficient sweepers; 
describing how the protocol constitutes an enhancement or improvement 
over previously adopted commitments contained in the MAG plan; 
addressing trackout associated with facilities and activities regulated 
by Maricopa County by notifying the County when rule violations are 
observed, and; providing for annual reevaluation of the protocol.
---------------------------------------------------------------------------

    \55\ Salt River plan, Appendix D.
---------------------------------------------------------------------------

    As an example of specific measures resulting from adopted municipal 
resolutions, the City of Phoenix developed a protocol to comply with 
its adopted Resolution No. 20114, Measure 04-DC-1. The protocol 
specifies that street sweeping schedules will increase from the current 
14-day sweeping cycle to a 7-day cycle in a targeted area, defined as 
bounded by Van Buren Street, Baseline Road, 10th Street, and 59th 
Avenue in the Salt River area.\56\ Also, the City reports that its 
entire fleet of street sweepers are now PM-10 efficient.\57\
---------------------------------------------------------------------------

    \56\ ``City of Phoenix 2004 Protocol & Implementation Plan For 
Paved Streets With Potential for Dust Emissions'', Salt River plan, 
Appendix D.
    \57\ Ibid., pg. 5.
---------------------------------------------------------------------------

    In addition, the City of Phoenix included $330,000 in its 2004/05 
budget for the purchase of two street sweepers \58\ and provides for 
street improvements (i.e., curb and gutter) on approximately 0.8 mile 
of 43rd Avenue between Lower Buckeye Road and the Salt River.\59\
---------------------------------------------------------------------------

    \58\ Salt River plan, Appendix D, City of Phoenix Resolution No. 
20114, Measure 04-DC-1.
    \59\ Ibid., Measure 04-DC-2.
---------------------------------------------------------------------------

    MCDOT adopted the following street sweeping protocol: \60\
    (a) Identify and target arterial and collector ``high dust'' roads 
through routine field supervisor roadway inspections and sweep such 
roads at least three times per month.\61\
---------------------------------------------------------------------------

    \60\ Salt River plan, Appendix D, Maricopa County Resolution No. 
C-85-05-005-0-00, Measure 5.
    \61\ The protocol indicates that this sweeping frequency is 
double the previous frequency.
---------------------------------------------------------------------------

    (b) Sweep all targeted roads with certified PM-10 efficient street 
sweepers by February 2, 2005.
    (c) Have all MCDOT field inspectors and supervisors report trackout 
associated with facilities and activities regulated by Maricopa County 
to MCAQD when rule violations are observed.
    (d) Re-evaluate the protocol annually to ascertain its 
effectiveness, update the list of roads swept with increased frequency, 
and submit this list to MCAQD annually.
    Because we believe the municipal, County,\62\ and State resolutions 
strengthen the SIP and are consistent with our policy and guidance 
regarding enforceability and SIP relaxations, we propose to approve 
them under CAA section 110(k)(3) as SIP strengthenings.
---------------------------------------------------------------------------

    \62\ Measure 5 of the Maricopa County Board Resolution contains 
the relevant street sweeping commitment.
---------------------------------------------------------------------------

IV. Statutory and Executive Order Reviews

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
proposed action is not a ``significant regulatory action'' and 
therefore is not subject to review by the Office of Management and 
Budget. For this reason, this action is also not subject to Executive 
Order 13211, ``Actions Concerning Regulations That Significantly Affect 
Energy Supply, Distribution, or Use'' (66 FR 28355, May 22, 2001). This 
proposed action merely proposes to approve state law as meeting Federal 
requirements and imposes no additional requirements beyond those 
imposed by state law. Accordingly, the Administrator certifies that 
this proposed rule will not have a significant economic impact on a 
substantial number of small entities under the Regulatory Flexibility 
Act (5 U.S.C. 601 et seq.). Because this rule proposes to approve pre-
existing requirements under state law and does not impose any 
additional enforceable duty beyond that required by state law, it 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).

[[Page 39259]]

    This proposed rule also does not have tribal implications because 
it will not have a substantial direct effect on one or more Indian 
tribes, on the relationship between the Federal Government and Indian 
tribes, or on the distribution of power and responsibilities between 
the Federal Government and Indian tribes, as specified by Executive 
Order 13175 (65 FR 67249, November 9, 2000). This action also does not 
have Federalism implications because it does not have substantial 
direct effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government, as specified 
in Executive Order 13132 (64 FR 43255, August 10, 1999). This action 
merely proposes to approve a state rule implementing a Federal 
standard, and does not alter the relationship or the distribution of 
power and responsibilities established in the Clean Air Act. This 
proposed rule also is not subject to Executive Order 13045 ``Protection 
of Children from Environmental Health Risks and Safety Risks'' (62 FR 
19885, April 23, 1997), because it is not economically significant.
    In reviewing SIP submissions, EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. In 
this context, in the absence of a prior existing requirement for the 
State to use voluntary consensus standards (VCS), EPA has no authority 
to disapprove a SIP submission for failure to use VCS. It would thus be 
inconsistent with applicable law for EPA, when it reviews a SIP 
submission, to use VCS in place of a SIP submission that otherwise 
satisfies the provisions of the Clean Air Act. Thus, the requirements 
of section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (15 U.S.C. 272 note) do not apply. This proposed rule does 
not impose an information collection burden under the provisions of the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental 
relations, Particulate matter, Reporting and recordkeeping 
requirements.


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

    Dated: June 30, 2006.
Alexis Strauss,
Acting Regional Administrator, Region IX.
[FR Doc. 06-6111 Filed 7-11-06; 8:45 am]

BILLING CODE 6560-50-P
