[Federal Register Volume 62, Number 149 (Monday, August 4, 1997)]
[Rules and Regulations]
[Pages 41856-41865]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-20470]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[AZ 69-0012; FRL-5867-9]


Approval and Promulgation of Implementation Plans; Arizona--
Maricopa County PM-10 Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is approving in part and disapproving in part the final 
Plan for Attainment of the 24-hour PM-10 Standard--Maricopa County PM-
10 Nonattainment Area, (May 1997) (microscale plan) submitted by the 
Arizona Department of Environmental Quality on May 7, 1997. The 
microscale plan evaluates attainment of the 24-hour particulate matter 
(PM-10) national ambient air quality standard at four monitoring 
locations in the Maricopa County (Phoenix), Arizona, PM-10 
nonattainment area. EPA is approving the attainment and reasonable 
further progress demonstrations for two of these sites (Salt River and 
Maryvale) and disapproving them for two other sites (West Chandler and 
Gilbert). EPA is also approving the reasonably available control 
measure/best available control measure demonstrations in the microscale 
plan for some significant source categories of PM-10 but disapproving 
them for others.

EFFECTIVE DATE: September 3, 1997.

FOR FURTHER INFORMATION CONTACT: Frances Wicher, Office of Air Planning

[[Page 41857]]

(AIR-2), U.S. Environmental Protection Agency, Region 9, 75 Hawthorne 
Street, San Francisco, California 94105. (415) 744-1248.

SUPPLEMENTARY INFORMATION:

I. Background

    Portions of Maricopa County are designated nonattainment for the 
PM-10 national ambient air quality standards (NAAQS) 1 and 
were originally classified as ``moderate'' pursuant to section 188(a) 
of the Clean Air Act (CAA or Act). 56 FR 11101 (March 15, 1991). The 
State of Arizona developed and submitted to EPA a PM-10 State 
Implementation Plan (SIP) revision intended to address the CAA 
requirements for moderate PM-10 nonattainment areas. These moderate 
area requirements are described in the notice of proposed rulemaking 
for this action (henceforth ``the proposal''). 62 FR 31026 (June 6, 
1997). EPA approved this SIP revision on April 10, 1995. 59 FR 38402. 
This approval was subsequently vacated by the Ninth Circuit Court of 
Appeals in Ober v. EPA, 84 F.3d 304 (9th Cir. 1996). In vacating EPA's 
approval of the plan, the court found that the State had failed to 
address the 24-hour PM-10 standard in its moderate area plan and 
ordered EPA to require the State to submit moderate area reasonably 
available control measure (RACM), attainment and reasonable further 
progress (RFP) demonstrations for that standard. 84 F.d. at 311.
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    \1\ There are two PM-10 NAAQS, a 24-hour standard and an annual 
standard. 40 CFR 50.6.
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    Just before the court issued its order, EPA found that the Maricopa 
area failed to attain the PM-10 standards by the statutory deadline for 
moderate areas of December 31, 1994. See 61 FR 21372 (May 10, 1996). As 
a result, the area was reclassified to ``serious.'' The State is now 
required to develop and submit a new PM-10 plan meeting the CAA 
requirements for serious PM-10 nonattainment areas by December 10, 
1997. Statutory requirements for serious area PM-10 requirements are 
described in the proposal at 62 FR 31026-31027.
    In order to comply with the court's order without diverting 
resources from the serious area plan effort, EPA, in consultation with 
the Arizona Department of Environmental Quality (ADEQ) and the Maricopa 
County Environmental Services Department (MCESD), decided that the 
State would incorporate the moderate area plan elements for the 24-hour 
standard into the serious area plan, but would split that planning 
effort into two related parts. Accordingly, EPA required submittal of a 
limited, locally-targeted plan (known as the microscale plan) meeting 
both the moderate and serious area requirements for the 24-hour 
standard by May 9, 1997 and a full regional plan meeting those 
requirements for both the 24-hour and annual standards by December 10, 
1997. Thus, the microscale and regional plans taken together would 
satisfy both the moderate area requirements mandated by the court and 
the serious area planning requirements for both standards.
    The submittal deadlines and requirements applicable to the 
microscale plan are contained in letters dated September 18, 1996 and 
March 5, 1997 from Felicia Marcus, Regional Administrator, EPA Region 
IX, to Russell Rhoades, Director, ADEQ (Marcus letter). In brief, the 
microscale plan was to address the 24-hour standard violations at five 
specific monitors in the metropolitan Phoenix area and meet the 
statutory RACM, best available control measures (BACM), attainment, and 
RFP requirements for moderate and serious PM-10 areas. Finally, the 
plan was to contain the air quality modeling and emissions inventory 
information necessary to support the required demonstrations and meet 
the generally applicable SIP requirements for reasonable notice and 
public hearing under section 110(l); necessary assurances that the 
implementing agencies have adequate personnel, funding and authority 
required by CAA section 110(a)(2)(E)(i) and 40 CFR 51.280; and the 
description of enforcement methods as required by 40 CFR 51.111. A 
complete discussion of the EPA's rationale and requirements for the 
microscale plan can be found in the proposal at 62 FR 31027-31029.

II. Summary of the Proposal

    ADEQ submitted the Plan for Attainment of the 24-hour PM-10 
Standard--Maricopa County PM-10 Nonattainment Area (May, 1997) (plan or 
microscale plan) to EPA on May 9, 1997. EPA proposed to approve in part 
and disapprove in part this plan on June 6, 1997 (62 FR 31025). EPA's 
evaluation of the microscale plan and its proposed action on that plan 
are summarized here; a complete discussion can be found in the proposal 
and in the technical support document (TSD) for this rulemaking.
    The microscale plan addresses exceedances of the 24-hour PM-10 
NAAQS at the Salt River, Maryvale, Gilbert, and West Chandler PM-10 
monitoring sites in the metropolitan Phoenix area.2 The plan 
showed that 24-hour exceedances at the Salt River site were primarily 
due to fugitive dust from earth moving, industrial haul roads, unpaved 
parking lots, and unpaved roads; at the Maryvale site, from disturbed 
cleared area; at the Gilbert site from agricultural field aprons and 
unpaved parking lots; and at the West Chandler site, from agricultural 
fields, agricultural field aprons, vacant lots, and disturbed cleared 
areas. Plan, pp. 17-19 and 62 FR 31031-31032. The plan addressed 
attainment at these localized sites by identifying RACM and BACM 
appropriate for controlling these types of fugitive dust sources. 
However, the localized nature of the microscale plan precluded a 
determination regarding the extent to which the identified RACM and 
BACM should be implemented to address emissions over a larger 
geographic area, as well as an assessment of the overall effectiveness 
of these measures when applied throughout the nonattainment area as a 
whole. These determinations will be addressed by the State in the full 
regional plan. Plan, pp. 21-22 and 62 FR 31031-31032.
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    \2\ The fifth monitoring site, East Chandler, was dropped from 
the microscale plan because of a lack of sufficient inventory data 
to evaluate exceedances at that site. 62 FR 31029, ftn 10.
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    In Maricopa County, most fugitive dust sources are subject to 
MCESD's Rule 310 (Open Sources of Fugitive Dust). MCESD committed in 
the microscale plan to a number of improvements to the implementation 
of Rule 310. These improvements are described in the plan (pp. 32-36) 
and discussed in EPA's proposed action on the plan, 62 FR 31032-31034. 
These improvements were primarily targeted at sources subject to 
permitting (such as, earth moving, disturbed cleared roads, and 
industrial haul roads) under MCESD's rules. For non-permitted sources 
(such as vacant lots, agricultural sources, unpaved parking lots, and 
unpaved roads), the microscale plan did not provide for proactive 
implementation of controls. 62 FR 31034. In total, the plan contained 
sufficient controls to show attainment at the Salt River and Maryvale 
sites but also showed that additional controls were needed before 
attainment could be demonstrated at the West Chandler and Gilbert 
sites. Plan, pp. 37-40 and 62 FR 31025.
    Based on its evaluation of the microscale plan, EPA proposed to 
approve the provisions for implementing RACM and BACM for the 
significant source categories of disturbed cleared areas, earth moving,

[[Page 41858]]

and industrial haul roads and disapprove the provisions for 
implementing RACM and BACM for the significant source categories of 
agricultural fields, agricultural aprons, vacant lands, unpaved parking 
lots, and unpaved roads. EPA also proposed to approve the attainment 
and RFP demonstrations at the Salt River and Maryvale sites and 
disapprove these demonstrations at the West Chandler and Gilbert sites. 
Finally, EPA proposed to find that the plan met the the generally 
applicable SIP requirements for reasonable notice and public hearing 
under section 110(l); necessary assurances that the implementing 
agencies have adequate personnel, funding and authority under section 
110(a)(2)(E)(i) and 40 CFR 51.280; and the description of enforcement 
methods as required by 40 CFR 51.111. 62 FR 31035-31036.

III. Response to Public Comments on the Proposal

    EPA received comments on its proposal from the Arizona Center for 
Law in the Public Interest (ACLPI) and the Arizona Department of 
Environmental Quality. A summary of the most pertinent comments and 
EPA's responses to those comments follow. A complete summary of all the 
comments received and EPA's responses to those comments can be found in 
the TSD.
    In its June 9, 1997 comment letter, ACLPI incorporated by reference 
its April 28, 1997 comments to ADEQ. EPA responds to both sets of 
comments below.
    Comment: While ACLPI agrees with EPA's proposal to approve the 
various control measures in the microscale plan for inclusion in the 
SIP, it does not agree that these measures have been shown to 
constitute BACM for all the source categories addressed and notes that 
the State indicated in the draft microscale plan that an evaluation of 
BACM was being deferred to the full serious plan. ACLPI asserts that 
the final microscale plan does not contain a complete BACM analysis 
meeting all the requirements of EPA's PM-10 serious area guidance \3\ 
nor does the plan contain any explanation of why measures were 
rejected.
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    \3\ This guidance is referred to as the Addendum and is found in 
``State Implementation Plans for Serious PM-10 Nonattainment Areas, 
and Attainment Date Waivers for PM-10 Nonattainment Areas Generally; 
Addendum to the General Preamble for the Implementation of Title I 
of the Clean Air Act Amendments of 1990,'' 59 FR 41998 (August 16, 
1994)
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    Response: EPA's findings regarding the States' compliance with the 
RACM and BACM requirements in the context of the microscale plan 
recognize that this plan is limited in nature and, thus, is only a part 
of--is in essence a down payment on--the full serious area PM-10 plan 
contemplated by section 189(b) of the Act and relevant Agency guidance. 
Consequently, EPA agrees that these measures have not been shown to 
constitute complete BACM for the eight significant source categories in 
the microscale plan and that the plan does not contain a complete BACM 
analysis meeting the requirements of the Addendum. EPA acknowledged the 
limited nature of these determinations when it stated, in its proposed 
action on the microscale plan, that the proposed findings on RACM and 
BACM implementation are ``applicable only to the microscale plan and 
thus * * * will not constitute EPA's final decision as to the State's 
full compliance with CAA section 189(a)(1)(C) and 189(b)(1)(B) for RACM 
and BACM for the eight source categories.'' 62 FR 31035. EPA further 
stated in its proposal, ``[t]he subject of this proposed action is the 
microscale plan only; the full regional plan is not due until late 
1997[; therefore,] it is * * * premature to determine if the microscale 
plan, in and of itself, fully complies with the Clean Air Act 
requirements for moderate and serious PM-10 nonattainment areas.'' 62 
FR 31036. The proposal goes on to conclude that the State ``will need 
to re-evaluate appropriate RACM and BACM for these sources in the full 
regional plan.'' 62 FR 31035.
    The Addendum defines BACM, among other things, as the maximum 
degree of emission reduction achievable, considering energy, economic 
and environmental impacts and outlines a multi-step process for 
identifying BACM. Addendum at 42010-42014. The steps are (1) 
development of a detailed emission inventory of PM-10 sources and 
source categories, (2) air quality modeling evaluating the impact on 
PM-10 concentrations of the various sources and source categories to 
determine which are significant, and (3) identifying potential BACM 
controls for significant source categories including their 
technological feasibility, costs, and energy and environmental impacts.
    Although detailed information was developed in the microscale plan 
regarding factors such as the number and type of emissions sources and 
their emissions, this information was gathered only for the limited 
geographic area around the monitors addressed by the microscale plan. 
However, EPA and the State agreed that any identified BACM controls 
resulting from the microscale plan would be implemented regionally, 
that is, throughout the entire nonattainment area. Marcus letter. As a 
technological and planning matter, it is more logical to address the 
third step of the BACM analysis (as outlined in the Addendum) by 
assessing the effects of control implementation on the regional scale 
rather than the localized one considered by the microscale 
plan.4 In other words, while significant sources of PM-10 
and candidate BACM for those sources could be identified within the 
scope of the microscale plan, the final determination about whether 
such controls represent the maximum degree of emission reductions 
achievable given economic, energy and environmental considerations 
depends on the type of information being developed for the regional 
plan due in December.5 Therefore, it is reasonable for the 
State to undertake the full BACM analysis in the context of the 
regional plan and for EPA to defer its assessment of the State's 
compliance with the requirements accordingly.
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    \4\ Regional implementation assured that the air quality 
benefits associated with the controls identified at a microscale 
site were realized over the much larger nonattainment area and not 
just narrowly at the particular microscale site. The regional 
implementation approach was taken because EPA believed that these 
regional air quality benefits would outweigh any benefits that would 
have accrued from a full BACM analysis resulting in implementation 
of controls at the microscale sites alone. The Agency believes that 
this preferable approach warrants the brief six month deferment of 
the full BACM analysis to the full regional plan.
    \5\ An example will illustrate the importance of this regional 
information in determining BACM: the microscale plan may have shown 
that it is economically feasible to pave all unpaved roads within a 
small microscale domain, but a regional analysis may very well show 
that it is economically infeasible to do so within the almost 2,900 
square miles of the Maricopa County PM-10 nonattainment area.
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    This is not to say that some parts of the BACM analysis were not 
appropriate for the microscale plan. In fact, the State performed the 
BACM analysis required by the Addendum except for the final detailed 
evaluation of economic, energy, and environmental considerations to 
determine if the measures represented the maximum degree of control. It 
developed an emission inventory around each monitor and evaluated the 
impact of each source category on ambient concentrations. It also 
identified candidate BACM controls for most significant source 
categories (Plan, Appendix B, pp. 4-8--4-9) by reviewing EPA's fugitive 
dust guidance documents and PM-10 controls programs in other areas 
including the South Coast (Los Angeles) Air Quality Management District 
and the Coachella Valley (Palm Springs), California. Plan, Appendix B, 
p. 3-1. Based on the documentation of this effort in the

[[Page 41859]]

microscale plan, EPA has determined, given the inherent limitations of 
the microscale approach, that the plan's BACM analysis is consistent 
where relevant with the guidance in the Addendum. 62 FR 31031-31032.
    Comment: ACLPI disagrees with EPA's assertions that some of the 
dust control strategies in the microscale plan constitute BACM because 
they represent an improvement over existing RACM. ACLPI argues that a 
control measure is not BACM merely because it is more effective than an 
existing measure or merely because it emphasizes prevention; rather 
BACM is the maximum degree of emission reduction achievable, 
considering energy, economic and environmental impacts.
    Response: As discussed immediately above, a full BACM analysis as 
contemplated by the Addendum was not possible, for the limited purposes 
of the microscale plan, in the microscale plan; therefore, it was not 
possible to determine if any particular candidate BACM represented the 
``maximum degree of emission reduction achievable, considering energy, 
economic and environmental impacts.'' The Addendum, however, recognizes 
that the source categories for PM-10 are varied and, consequently, does 
not limit its description of BACM to this definition. In the Addendum, 
BACM can ``include, though it is not limited to, expanded use of some 
of the same types of control measures as those included as RACM in the 
moderate area SIP.'' Addendum at 42013. This is necessarily the case 
because the universe of control measures available to States to address 
certain PM-10 sources, such as fugitive dust, is limited. The technical 
guidance on control of fugitive dust sources \6\ makes this point: 
``When a fugitive dust source has been controlled under a RACM 
strategy, the implementation of BACM will generally involve additive 
measures that consist of a more extensive application of fugitive dust 
control measures imposed under RACM.'' Fugitive Dust BACM TID, p. 1-6.
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    \6\ ``Fugitive Dust Background Document and Technical 
Information Document for Best Available Control Measures,'' EPA 450/
2-92-004, September 1992 (Fugitive Dust BACM TID). This document is 
one of several guidance documents that EPA was required to develop 
on RACM and BACM for certain PM-10 source categories pursuant to CAA 
section 190.
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    EPA also states in the Addendum a preference that BACM include 
pollution preventive measures and measures that provide for long-term 
sustained progress toward attainment rather than quick, temporary 
controls. Addendum at 42013. With respect to this criterion, EPA's 
fugitive dust guidance states: ``The reduction of source extent and the 
incorporation of process modifications or adjusted work practices which 
reduce the amount of exposed dust-producing material constitute 
preventive [best available control] measures for control of fugitive 
dust emissions.'' Fugitive Dust BACM TID, p. 1-6.
    Given that both the Addendum and the Fugitive Dust BACM TID provide 
that adoption of control measures that go beyond or expand the use of 
adopted RACM and that emphasize prevention constitute BACM for fugitive 
dust sources especially, it is appropriate for EPA to assess the BACM 
analysis in the microscale plan in terms of these criteria, as well as 
to conclude that the microscale plan's BACM demonstration, within the 
narrow scope of that plan, is acceptable. These criteria are discussed 
in greater detail in the proposal and TSD (62 FR 31029 and TSD, p. 21) 
and are, as noted, fully consistent with the Addendum. Finally, EPA 
notes that, given the limited set of measures available for control of 
PM-10 fugitive dust sources, the BACM selected for implementation after 
the complete BACM analysis required by the Addendum is performed for 
the regional plan may be the same as those identified in the microscale 
plan.
    Comment: ACLPI asserts that EPA must disapprove the BACM 
demonstration for all source categories in the microscale plan, not 
just the five that EPA proposed and that such a disapproval would not 
impose any severe or unexpected burdens on the State since the State is 
already planning to do a full BACM analysis after submission of the 
microscale plan. ACLPI asserts that EPA's approval of the state's 
``thin or nonexistent'' analysis as a BACM demonstration would create a 
serious risk of weakening the entire particulate matter program because 
other states may well cite EPA's action here as evidence of what 
constitutes BACM for these sources when in fact there are much more 
effective measures in practice.
    Response: EPA has found that the microscale plan contains adequate 
BACM demonstrations for three source categories and inadequate BACM 
demonstrations for five categories and has fully documented its 
determinations in the proposal and supporting TSD. 62 FR 31031-31035 
and TSD, pp. 24-34. EPA based its determination on Clean Air Act 
requirements, the Addendum, the requirements for the microscale plan 
laid out in the Marcus letters, the inherent limitations of the 
microscale approach, and the information presented in the microscale 
plan.
    ACLPI's concern about risking the entire particulate matter program 
because other states may cite to this action is unfounded. First, EPA 
has made it clear that its findings are limited to the microscale plan 
and that ``the State will need to re-evaluate appropriate RACM and BACM 
for these sources in the full regional plan.'' 62 FR 31035. Second, as 
noted by ACLPI in its comments, the final determination of BACM is 
based, per EPA guidance, on a showing that a selected control is the 
``maximum degree of emission reduction achievable, considering energy, 
economic and environmental impacts.'' Addendum at 42010. Since 
determining BACM for significant source categories like those in the 
microscale plan is necessarily based on area-specific information 
regarding energy, economics, and environmental impacts, each serious 
PM-10 area must perform its own BACM analysis. While other areas may 
review the microscale plan to identify candidate BACM measures, they 
cannot assume that something is or is not BACM simply because it has 
been determined to be so in the microscale plan.
    Comment: ACLPI comments that the plan does not clearly identify 
which control strategies will be required in a given situation, noting 
that Rule 310 and the dust control plan form list various control 
options, some of which may constitute BACM but there is no assurance 
that the BACM option will be chosen by the source in any given 
situation. On the same theme, ACLPI notes that while the attainment 
demonstration at the Salt River site assumed watering to the depth of 
the cut, the plan does not clearly require this strategy in every 
situation. ACLPI asserts that EPA should condition its approval of the 
attainment demonstration at the Salt River site on the County providing 
a clear commitment to requiring this strategy.
    Response: While the dust control plan checklist covers a broad 
range of dust generating activities, it narrowly limits the control 
options available for any particular activity. For example, the BACM 
identified in the microscale plan for disturbed cleared areas is 
stabilization of the surface at all times including 
weekends.7 This BACM is reflected on the checklist in the 
category ``temporary stabilization'' which requires stabilization of 
disturbed cleared areas (including weekends and

[[Page 41860]]

holidays) using one of two equivalent control techniques--water to form 
a crust or application of chemical stabilizers to form a 
crust.8, 9 Plan, p. 34.
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    \7\ The modeling analysis indicated that the needed control was 
stabilization or crusting of disturbed surface areas at all times 
including weekends. The analysis did not depend on a particular 
control technique for achieving this stabilization. Plan, p. 27.
    \8\ The equivalency of these two measures is shown in Table 4-1 
(Plan, p. 22) in the microscale plan which gives the control 
efficiency of chemical stabilization at 82-97 percent and that of 
watering to maintain a crust at 90 percent.
    \9\ This limitation on control options is also true for the 
other two source categories for which EPA is approving the RACM/BACM 
demonstration: industrial haul roads (3 options, stabilize with 
gravel, dust suppressant or water) and earthmoving (2 options, water 
to the depth of the cut or water to eliminate or minimize visible 
emissions). Plan, p. 34.
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    For the Salt River site, ACLPI's comment illustrates the importance 
of regional evaluation in the final determination of BACM. While 
wetting to the depth of the cut was appropriate for the cutting 
operation at the Salt River site, it may not always be appropriate at 
cutting operations elsewhere in the nonattainment area. For example, 
soil types vary throughout the Maricopa area and in some places a 
coleche layer or patch may be present. A coleche layer is impermeable 
to water and thus watering to the depth of the cut is not feasible when 
a coleche layer is encountered during cutting operations. Plan, 
Appendix G, p. 2. Since dust control is still needed where water to the 
depth of the cut is impracticable, the provision of a second equivalent 
control option--in this case, watering as necessary to prevent or 
minimize visible emissions--is reasonable and necessary. Since the 
checklist already requires application of at least one of these two 
options, EPA does not believe that it need condition its approval of 
the attainment demonstration at the Salt River monitor on the County 
providing a clear commitment to require watering to the depth of the 
cut in every situation.
    Comment: Stating that the Clean Air Act requires that the SIP 
assure adequate resources for enforcement and that the attainment 
demonstrations in the microscale plan depend on adequate enforcement of 
Rule 310, ACLPI asserts that the County continues to operate this 
program with ``grossly'' inadequate staffing levels. ACLPI notes that 
the plan indicates that the County is dedicating only 1.75 FTEs to the 
dust control program and asserts that other county inspectors are 
``available'' to perform field observations and respond to complaints, 
but apparently only when their other duties allow and that the County 
does not quantify or even estimate how much time these other inspectors 
will spend on Rule 310 enforcement. ACLPI asserts that, because there 
is no commitment to assign any specified level of staffing from this 
group, EPA must assume for SIP purposes that it will be zero.
    Response: The microscale plan does not indicate that the County is 
dedicating only 1.75 FTE to implementing Rule 310. The plan clearly 
indicates that 1.75 FTE is the number of staff that are assigned full 
time to Rule 310 implementation and that there are a number of other 
personnel who work on Rule 310 implementation as part of their 
responsibilities and as needed. These other personnel include the 
public involvement coordinator, the small business assistance program, 
and 19 other inspectors, aides, engineers and supervisors.10 
Plan, Appendix E, Letter, Joy Bell, MCESD, to Joe Gibbs, ADEQ, May 6, 
1997 (Bell letter).11 It should also be noted that the 
County's commitment to use these other resources to implement Rule 310 
is not ``when available'' as ACLPI asserts but ``as needed.'' Plan, 
Appendix E, Bell letter. The Cities are also contributing resources to 
improving implementation of Rule 310 through the regional coordination 
effort. Plan, Appendix E, ``Resolutions Adopted by Various Cities and 
Towns within Maricopa County'' (city resolutions).
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    \10\ These inspectors are the ones who inspect stationary 
sources that may have Rule 310 sources, such as earth moving, 
located on them (like many of the stationary sources surrounding the 
Salt River monitor) and respond to complaints. Letter, Joy A. Bell, 
MCESD, to Frances Wicher, EPA, July 2, 1997 (July 2 Bell letter).
    \11\ The Maricopa County Board of Supervisors adopted on May 14, 
1997 a resolution committing to implement improvements to the 
administration of the fugitive dust control program and to foster 
interagency cooperation to address fugitive dust. The microscale 
plan included the draft resolution, and ADEQ transmitted the adopted 
resolution to EPA on May 27, 1997. See letter from Nancy Wrona, 
ADEQ, to John Kennedy, EPA.
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    EPA does not believe that it must be assumed for SIP purposes that 
the resources from these other inspectors must be zero simply because 
the County did not quantify or even estimate how much time these other 
inspectors will spend on Rule 310 enforcement. Inspectors inspect 
facilities, and most facilities have multiple, distinct emission 
points. Each point is potentially subject to a different rule or 
regulation. Because of this, inspectors are trained to be able to 
inspect facilities for compliance with a number of rules.12 
Because an inspector may do inspections for compliance with multiple 
rules on a single site visit, it is difficult, if not impossible, to 
tease out just how much time is or will be spent inspecting for 
compliance with a particular rule. Thus, the lack of a specific 
numerical FTE commitment to Rule 310 implementation for the 19 
inspectors, aides, engineers, and supervisors does not bar considering 
their availability in determining if the plan provides for adequate 
resources.13
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    \12\ EPA considers an on-site visit to a facility an inspection 
only if it meets EPA's Level II inspection requirements. In short, 
Level II inspections require an assessment of the compliance status 
of all units within a source that are subject to SIP, New Source 
Performance Standards, or National Emission Standards for Hazardous 
Air Pollutant regulation. ``Revised Compliance Monitoring 
Strategy,'' March 1991, (Revised CMS) p. 3.
    \13\ EPA again notes that the MCESD committed to use these 
inspection resources as needed to implement Rule 310. The County 
also committed to revising its standard operating procedures for 
stationary source inspections to include Rule 310 compliance checks. 
Plan, Appendix E, Bell letter.
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    Most importantly, MCESD's commitments to improving Rule 310 
implementation go well beyond just adding staff. The commitments 
include upgrading the Rule's implementation guidelines, educating the 
regulated community about its responsibilities under the Rule, revising 
its inspection procedures, providing a small business assistance 
program, and coordinating with the Cities and towns of Maricopa County. 
To judge the adequacy of the resources to carry out the microscale 
plan's control strategy, EPA evaluated this entire set of commitments 
as well as the information contained in the plan about the nature and 
extent of sources contributing to the 24-hour PM-10 standard 
exceedances and the controls needed to eliminate these exceedances. 
This evaluation (which is discussed extensively in the proposal and the 
TSD) led EPA to two conclusions: One, that the microscale plan provided 
the necessary assurances that adequate resources are available to 
implement Rule 310 for permitted sources, and two, that the plan did 
not provide the required assurances that controls will be implemented 
by Maricopa County on non-permitted sources. As a result of these 
conclusions, EPA is approving the RACM/BACM demonstration for permitted 
source categories and disapproving the demonstrations for the non-
permitted source categories.
    Comment: In its April 28, 1997 comments ACLPI notes that in 
addition to inspecting 1,200 to 1,600 new permittees every year, these 
inspectors must respond to complaints and monitor compliance by 
previously permitted facilities and that it seems impossible that the 
County will be able to inspect each new permittee once per year unless 
the inspectors neglect other facilities. ACLPI notes further that once 
per year inspection is grossly inadequate in many cases--particularly 
where a source has a chronic problem

[[Page 41861]]

and requires repeated visits. Finally, ACLPI states that the County 
does not explain how it expects to identify unpermitted sources that 
fail to self-report.
    Response: MCESD has committed to inspecting all sites of 10 acres 
and larger (Plan, Appendix E, Bell letter) and targets smaller sources 
based on past history of the contractor and/or developer and field 
observations. Plan, p. 12. Resources in the plan are adequate for this 
level of inspection as committed to by MCESD. Between June 1, 1996 and 
May 31, 1997, the County inspected 43 percent of sources 10 acres or 
greater. July 2 Bell letter. This was the inspection rate with only 
0.75 FTE dedicated to the program. With the additional FTE allocated to 
the program, the County should easily meet its commitment. Plan, 
Appendix E, Bell letter. The County is upgrading and integrating its 
database to be better able to identify problem sources. Plan, Appendix 
E, Bell letter. In addition, the cooperative program with Cities that 
includes better training of City inspectors on Rule 310 requirements 
should also help identify and target problem sources. Plan, Appendix E, 
city resolutions.
    Focusing resources on and targeting annual inspections to larger 
sources (with their inherent ability to be more polluting) are 
consistent with EPA's inspection guidance which calls for inspecting 
large sources annually but does not specify an inspection frequency for 
smaller sources.14
---------------------------------------------------------------------------

    \14\ ``Revised Compliance Monitoring Strategy,'' March 1991, 
Appendix 5. In California, most air pollution control districts 
inspect all their minor sources at least once every two (e.g., 
Ventura County) to four years (South Coast). See FY 1995-97 
Compliance Operating Plans.
---------------------------------------------------------------------------

    The County addressed its method for identifying unpermitted sources 
in the microscale plan and agreed to provide an annual summary of 
notices of violations and citations for failure to obtain earthmoving 
permits. Plan, Appendix G, p. 18.
    Comment: In its April 28, 1997 comments, ACLPI enclosed excerpts of 
EPA's July, 1992 audit of the County's Air Quality Program. ACLPI 
states that among other things, the audit found that the County failed 
to inspect many facilities on an annual basis, that enforcement and 
penalties were grossly inadequate, and that there was no program to 
identify unpermitted facilities. ACLPI also enclosed a copy of the 1996 
internal County Audit finding that the Air Pollution program was 
seriously understaffed, and that the County had no process in place to 
verify the accuracy of emissions survey information submitted by 
sources. ACLPI asserts that in light of these findings, the County 
cannot adequately expand Rule 310 enforcement by adding just one FTE.
    Response: The County has made a number of changes to its program to 
address EPA's and the County auditor's findings. As noted in the 
microscale plan, MCESD has added five inspectors since January, 1996 
(Plan, Appendix G, p. 26) and has moved to improve its database 
tracking systems to address problems in verifying the accuracy of 
emission survey information submitted by sources. (See, in general, 
Memorandum, Al Brown, Director, MCESD, to Ross Tate, Lead Auditor, 
Internal Audit Department, ``Maricopa County Environmental Services 
Department's Response to the June 1996 Performance Audit,'' July 12, 
1996, reproduced in the Plan, Appendix G). EPA evaluated MCESD's 
enforcement policy for the proposal and found that it is adequate to 
meet the requirements of 40 CFR 51.111(a) and CAA section 110(a)(2)(C). 
62 FR 31036.
    Comment: ACLPI also takes issue with EPA's assertion that the state 
need not control source categories that contribute less than 5 
g/m\3\ to a location of expected 24-hour exceedance. ACLPI 
claims that there is absolutely no authority in the Act for EPA to 
exempt such sources and that such an exemption is contrary to the Act's 
emphasis on timely attainment and protection of health. Control of a 
source category contributing 5 g/m\3\, could make a difference 
between attainment and nonattainment. ACLPI gives, as an example of its 
position, a site with ambient 24-hour levels in the 155 to 158 
g/m\3\ range and states that with a 80 percent control 
effectiveness of a source category contributing 5 g/m\3\, the 
site would become attainment. Based on this example, ACLPI concludes 
that it is wholly irrational for EPA to assert that such a source 
category is invariably de minimis. Further, ACLPI asserts that since 
PM-10 is a nonthreshold pollutant and thus adverse health effects 
increase on a linear scale with increased concentration, any reductions 
in PM-10 levels will have direct public health benefits.
    ACLPI claims that EPA does not explain where the de minimis 
principle comes into play in its proposed approval of the microscale 
plan and asks EPA to provide such an explanation in response to its 
comments.
    Response: Contrary to what the comment implies, EPA has not taken 
the position in this rulemaking--nor does the Agency's PM-10 serious 
area guidance take the position--that the State need not control 
insignificant source categories if such controls are needed for 
attainment. Rather, EPA's position is that the level of control on such 
insignificant sources need only be at the level required to demonstrate 
reasonable further progress and expeditious attainment. Addendum at 
42011. This level may not be at RACM, or if applicable, BACM levels. In 
other words, the de minimis policy is invoked only for determining 
which source categories need RACM and/or BACM and not for determining 
which source categories need controls for attainment. For serious PM-10 
nonattainment areas such as the Maricopa County area, the CAA requires 
the plan to include not only BACM but also a demonstration of 
attainment by the statutory deadline or the most expeditious 
alternative deadline practicable. Sections 189(b)(2) and 189(b)(1)(A). 
EPA's de minimis exemption for BACM does not interfere with this latter 
requirement for expeditious attainment and thus does not defeat the 
Act's requirement for timely attainment and protection of health.
    ACLPI's example is somewhat puzzling because it appears to assume 
that the 155 to 158 g/m\3\ level is made up of 30 plus source 
categories each contributing no more than 5 g/m\3\ (31 sources 
each contributing 5 g/m\3\=155 g/m\3\). This case is 
very unlikely; what is more likely is that there would be one or more 
significant source categories in addition to a number of insignificant 
ones that make up the 155-158 g/m\3\ level. Adequate controls 
on these significant sources would reduce ambient concentrations below 
the standard. Even if this were not the case, a state still is required 
to demonstrate attainment and thus would need to control at least some 
of the de minimis sources.
    EPA did provide a thorough explanation of how the de minimis 
principle affected its proposed action on the microscale plan. First, 
EPA fully discusses its de minimis policy and the rationale and legal 
authority for that policy in the Addendum at 42011. This policy states 
that BACM are required for all categories of sources in serious areas 
unless the State adequately demonstrates that a particular source 
category does not contribute significantly to nonattainment of the PM-
10 NAAQS and that a source category will be presumed to contribute 
significantly to a violation of the 24-hour NAAQS if its PM-10 impact 
at the location of the expected violations would exceed 5 g/
m\3\. EPA referenced

[[Page 41862]]

this discussion in the proposal in the section describing the 
requirement for BACM. 62 FR 31028. Secondly, EPA proposed, solely for 
the purposes of evaluating the microscale plan, to use the 5 
g/m\3\ action level to determine which source categories 
required RACM. 62 FR 31027.
    The State generated tables that listed each contributing source 
category at each monitor and that source's ambient impact at the 
monitor and at the point of maximum concentration. Plan, Tables 3-2 to 
3-5, pp. 17-19 and Appendix A, Tables 5-2 to 5-7 pp. 5-4--5-9 and Table 
7-3, p. 7-20. Based on the State's documentation, EPA determined and 
thoroughly documented which source categories were significant and thus 
required the application of RACM and BACM. 62 FR 31031 and TSD at pp. 
24-27. Except for some source categories at the Salt River monitor 
(TSD, p. 25), EPA did not also list the insignificant sources at each 
monitor since this information can be easily determined from the cited 
tables in the microscale plan and in the TSD (Tables II-3 through II-6, 
pp. 15-18). EPA has revised the TSD to specifically state which source 
categories EPA found insignificant. These following source categories 
were found to be insignificant: for the Salt River monitor, industrial 
yards, surface mining, other industrial activities, paved roads, 
trackout, and paved parking lots;15 for the Maryvale 
monitor, paved roads and unpaved roads;16 for the Gilbert 
monitor, paved roads and unpaved roads; and for the West Chandler 
monitor, paved and unpaved roads. It should be noted that even complete 
elimination of emissions from these insignificant sources would not 
have resulted in attainment at any of the monitors.
---------------------------------------------------------------------------

    \15\ Except for paved roads and paved parking areas, all these 
source categories are already subject to controls and in most cases 
are permitted by MCESD. Improvements to the overall permitting, 
inspection, and enforcement program at the County should improve 
implementation of the controls on these sources.
    \16\ Unpaved roads is a significant source category at the Salt 
River monitor and is thus a significant source category subject to 
RACM and BACM requirements even thought it was found to be an 
insignificant source category at the other three monitors. EPA is 
disapproving the plan's provisions for implementing RACM/BACM for 
this source category. The recently complete regional emission 
inventory shows that paved roads are very likely to be a significant 
source category in the regional plan. 1994 Regional PM-10 Emission 
Inventory for the Maricopa County Nonattainment Area (Draft Final 
Report), Maricopa Association of Governments, May 1997, p. 2-2.
---------------------------------------------------------------------------

    EPA has not made a finding that PM-10 is a nonthreshold pollutant; 
that is, that there is a direct linear relationship between PM-10 
reductions and health benefits to the public. Although the PM-10 NAAQS 
is set--indeed is required under CAA section 109(b) to be set--at 
levels that provide an adequate safety margin with respect to overall 
public health, some degree of risk remains at levels below the NAAQS. 
As described extensively in the recent proposal to revise the 
particulate matter NAAQS,17 the overall consistency and 
coherence of the epidemiological evidence strongly suggests a likely 
causal role of ambient particulate matter in contributing to adverse 
health effects (61 FR 65648 and 65653); however, at the same time, EPA 
cautioned that seeking to derive quantitative health risk estimates 
from this evidence includes significant uncertainties (61 FR 65649 and 
65653). These uncertainties are greater with respect to attempts to 
estimate health risks associated with the coarse fraction of 
particulate matter, that is, particulate with diameters between 2.5 and 
10 microns (61 FR 65649). Fugitive dust is primarily coarse fraction 
PM-10 and, as demonstrated in the microscale plan, fugitive dust is the 
primary cause of 24-hour PM-10 exceedances in the Maricopa County area. 
Thus, ACLPI's claim that PM-10 is a nonthreshold pollutant is 
unsupported by the current scientific evidence.
---------------------------------------------------------------------------

    \17\ 61 FR 65638 (December 13, 1996). The final notice revising 
the particulate matter standards was signed by the Administrator on 
July 16, 1997.
---------------------------------------------------------------------------

IV. Final Actions

A. Final Approvals and Disapprovals

    For the reasons discussed above and in the proposal, EPA is 
approving:
    (1) Under sections 172(c)(1), 189(a)(1)(C) and 189(b)(1)(B), the 
provisions for implementing RACM and BACM for the significant source 
categories of disturbed cleared areas, earth moving, and industrial 
haul roads; and
    (2) Under sections 189(a)(1)(B), 189(b)(1)(A), and 189(c), the 
attainment and RFP demonstrations for the Maryvale and Salt River 
sites.
    EPA is also approving the following as elements of the Arizona PM-
10 State Implementation Plan for the Maricopa area:
    (1) The resolution by the County of Maricopa to improve the 
administration of Maricopa County's fugitive dust control program and 
to foster interagency cooperation (adopted May 14, 1997);
    (2) The resolutions of intent to work cooperatively with Maricopa 
County to control the generation of fugitive dust pollution adopted by 
the Cities of Phoenix (April 9, 1997), Tempe (March 27, 1997), Chandler 
(March 27, 1997), Glendale (March 25, 1997), Scottsdale (March 31, 
1997), and Mesa (April 23, 1997) and the Town of Gilbert (April 15, 
1997); and
    (3) MCESD's Rule 310 (Open Fugitive Dust Sources), Rule 311 
(Particulate Matter from Process Industries) and Rule 316 (Nonmetallic 
Mineral Mining and Processing).18
---------------------------------------------------------------------------

    \18\ These rules were originally approved by EPA as part of the 
approval of the Maricopa moderate area plan in 1995. 60 FR 18009. 
While not at issue in the litigation regarding that plan, EPA's 
approval of these rules was also incidently vacated by the Ober 
decision; therefore, EPA must restore its approval of these rules.
---------------------------------------------------------------------------

    EPA is finding that the microscale plan: (1) provides the necessary 
assurances that the state and local agencies have adequate personnel, 
funding and authority under state law to carry out the submitted 
microscale plan; and (2) includes an adequate enforcement program, as 
required by CAA sections 110(a)(2)(E)(i) and 110(a)(2)(C).
    For the reasons discussed above and in the proposal, EPA is 
disapproving:
    (1) Under sections 172(c)(1), 189(a)(1)(C) and 189(b)(1)(B), the 
provisions for implementing RACM and BACM for the significant source 
categories of agricultural fields, agricultural aprons, vacant lands, 
unpaved parking lots, and unpaved roads; and
    (2) Under sections 189(a)(1)(B), 189(b)(1)(A), and 189(c)(1), the 
attainment and RFP demonstrations at the West Chandler and Gilbert 
sites.
    These approvals, disapprovals, and findings are applicable only to 
the microscale plan and thus, do not constitute EPA's final decision as 
to the State's full compliance with the requirements of CAA sections 
189(a)(1)(C) and 189(b)(1)(B) for RACM and BACM for the eight source 
categories and CAA sections 189(a)(1)(B), 189(b)(1)(A) and 189(c)(1) 
for attainment and RFP demonstrations at the Salt River, Maryvale, 
Gilbert and West Chandler monitoring sites. The State will need to re-
evaluate appropriate RACM and BACM for these sources in the full 
regional plan and, because regional factors may influence attainment at 
these sites, the State will need to re-evaluate modeling at all four 
sites as part of that plan.
    Nothing in this action should be construed as permitting or 
allowing or establishing a precedent for any future request for 
revision to any state implementation plan. Each request for a revision 
to the state implementation plan shall be considered separately in 
light of specific technical, economic and environmental factors and in 
relation to

[[Page 41863]]

relevant statutory and regulatory requirements.

B. Consequences of the Final Disapprovals

    As noted before, EPA required submittal of a microscale plan 
meeting both the moderate and serious area requirements for the 24-hour 
PM-10 standard by May 9, 1997 and a full regional plan meeting those 
requirements for both the 24-hour and annual standards by December 10, 
1997. The microscale and regional plans taken together would satisfy 
both the moderate area requirements for the 24-hour standard mandated 
by the Ninth Circuit in Ober and the serious area planning requirements 
for both standards. The subject of this final action is the microscale 
plan only; the full regional plan is not due until late 1997. It is, 
therefore, premature to determine if the microscale plan, in and of 
itself, fully complies with the Clean Air Act requirements for moderate 
and serious PM-10 nonattainment areas. Such a determination is not 
possible until the regional plan is submitted and reviewed.
    Because the microscale plan taken alone is not intended to fully 
comply with the RACM/BACM implementation, reasonable further progress 
and attainment demonstration requirements of the Clean Air Act, the 
final disapprovals of portions of the microscale plan do not trigger 
sanctions under CAA section 179(a). CAA section 179(a) requires the 
imposition of one of the sanctions in section 179(b) within 18 months 
of a disapproval if EPA ``disapproves a [State] submission * * * based 
on the submission's failure to meet one or more of the elements 
required by [the CAA]''. Because the purpose of the microscale plan was 
to, in effect, provide a down payment towards meeting certain 
requirements of the Act, EPA is not, at this time, proposing to find 
that the State has failed to meet any of the applicable elements 
required by the CAA as contemplated by section 179(a).
    EPA is subject to the terms of a consent decree approved by the 
U.S. District Court for the District of Arizona on March 25, 1997. Ober 
v. Browner, No. CIV 94-1318 PHX PGR. The consent decree obligates EPA 
to propose a federal implementation plan (FIP) for PM-10 in the 
Maricopa nonattainment area by March 20, 1998 and finalize that FIP by 
July 18, 1998 19 if the Agency disapproves all or part of 
the microscale plan. Therefore, based on the final disapprovals 
described above, EPA has an obligation to promulgate a regional 
moderate area PM-10 FIP that addresses the statutory requirements for 
attainment, RACM and RFP. Under the consent decree, the scope of this 
FIP obligation is reduced to the extent that EPA approves by July 18, 
1998 SIP provisions meeting the statutory requirements for RACM, RFP 
and attainment for moderate PM-10 nonattainment areas.
---------------------------------------------------------------------------

    \19\ The FIP deadlines each advance 2 months if EPA fails to act 
on the microscale plan by July 18, 1997.
---------------------------------------------------------------------------

    EPA believes, as is expressed in CAA section 101(a), that air 
pollution control is primarily the responsibility of states and local 
jurisdictions. Therefore, the Agency will work with the State of 
Arizona and the local agencies and jurisdictions responsible for PM-10 
planning and control in Maricopa County to develop SIP provisions that 
can reduce the scope of, or eliminate, any potential FIP. Considerable 
work is already underway or planned in the area to address the PM-10 
problem. As noted before, the full serious area regional PM-10 plan is 
due December 10, 1997. In addition, the microscale plan contains two 
initiatives, MCESD's regional program to address controls on 
nonpermitted sources and the ADEQ/MCESD/NRCS agreement to address 
fugitive dust from agricultural sources, that are targeted at 
significant but currently uncontrolled sources of PM-10.

V. Administrative Requirements

A. Executive Order 12866

    The Office of Management and Budget has exempted this regulatory 
action from Executive Order 12866 review.

B. Regulatory Flexibility Act

    Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA 
must prepare a regulatory flexibility analysis assessing the impact of 
any proposed or final rule on small entities. 5 U.S.C. 603 and 604. 
Alternatively, EPA may certify that the rule will not have a 
significant impact on a substantial number of small entities. Small 
entities include small business, small not-for-profit enterprises and 
government entities with jurisdiction over populations of less than 
50,000.
    SIP approvals under sections 110 and subchapter I, part D of the 
Clean Air Act, do not create any new requirements but simply approve 
requirements that the State is already imposing. Similarly, withdrawal 
of the FIP contingency process does not impose any new requirements. 
Therefore, because the federal SIP approval and FIP withdrawal does not 
impose any new requirements, the Administrator certifies that they do 
not have a significant impact on any small entities affected. Moreover, 
due to the nature of the Federal/state relationship under the Act, 
preparation of a regulatory flexibility analysis would constitute 
federal inquiry into the economic reasonableness of state action. The 
Act forbids EPA to base its actions concerning SIPs on such grounds. 
Union Electric Co. v. U.S.E.P.A., 427 U.S. 246, 256-66 (S. Ct. 1976); 
42 U.S.C. 7410(a)(2).

C. Unfunded Mandates

    Under sections 202 of the Unfunded Mandates Reform Act of 1995 
(``Unfunded Mandates Act''), 2 U.S.C. 1501-1571, signed into law on 
March 22, 1995, EPA must prepare a budgetary impact statement to 
accompany any proposed or final rule that includes a federal mandate 
that may result in estimated costs to State, local, or tribal 
governments in the aggregate; or to the private sector, of $100 million 
or more. Under Section 205, EPA must select the most cost-effective and 
least burdensome alternative that achieves that objectives of the rule 
and is consistent with statutory requirements. Section 203 requires EPA 
to establish a plan for informing and advising any small governments 
that may be significantly or uniquely impacted by this rule.
    EPA has determined that the approval action promulgated does not 
include a federal mandate that may result in estimate costs of $100 
million or more to either State, local, or tribal governments in the 
aggregate, or to the private sector.
    Through submission of these SIP revisions, the State and any 
affected local or tribal governments have elected to adopt the program 
provided for under sections 110 and 182 of the CAA. These rules may 
bind State, local, and tribal governments to perform certain actions 
and also require the private sector to perform certain duties. To the 
extent that the rules being approved today will impose any mandate upon 
the State, local, or tribal governments either as the owner or operator 
of a source or as a regulator, or would impose any mandate upon the 
private sector, EPA's action will impose no new requirements; such 
sources are already subject to these requirements under State law. 
Accordingly, no additional costs to State, local, or tribal 
governments, or to the private sector, result from this action. EPA has 
also determined that this action does not include a mandate that may 
result in estimated costs of $100 million or more to State, local, or

[[Page 41864]]

tribal governments in the aggregate or to the private sector. This 
federal action approves pre-existing requirements under State or local 
law, imposes no new Federal requirements, and withdraws other federal 
requirements applicable only to EPA. Accordingly, no additional costs 
to State, local or tribal governments, or to the private sector, 
results from this action.

D. Submission to Congress and the General Accounting Office

    Under 5 U.S.C. 801(a)(1)(A) added by the Small Business Regulatory 
Enforcement Fairness Act of 1996, EPA submitted a report containing 
this rule and other required information to the U.S. Senate, the U.S. 
House of Representatives and the Comptroller General of the General 
Accounting Office prior to publication of the rule in today's Federal 
Register. This rule is not a ``major rule'' as defined by 5 U.S.C. 
804(2).

E. Petitions for Judicial Review

    Under section 307(b)(1) of the Clean Air Act, petitions for 
judaical review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by October 3, 1997. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this rule 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 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, Carbon monoxide, 
Incorporation by reference, Intergovernmental relations.

    Note: Incorporation by reference of the State Implementation 
Plan for the State of Arizona was approved by the Director of the 
Federal Register on July 1, 1982.

    Dated: July 18, 1997.
Harry Seraydarian,
Acting Regional Administrator.

    For the reasons set forth in this notice, 40 CFR part 52 is amended 
as follows:

PART 52--[AMENDED]

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401-7671q.

Subpart D--Arizona

    2. Section 52.120 is amended as follows:
    a. By removing and reserving paragraph (c)(73);
    b. By revising paragraph (c)(74)(i)(A) and removing and reserving 
paragraph (c)(74)(i)(B);
    c. By removing paragraph (c)(77)(i)(A)(1) and redesignating 
paragraph (c)(77)(i)(A)(2) as (c)(77)(i)(A)(1); and
    d. By adding paragraph (c)(88), to read as follows:


Sec. 52.120  Identification of plan.

* * * * *
    (c) * * *
    (74) * * *
    (i) * * *
    (A) Maricopa County Environmental Services Department new Rule 316, 
adopted July 6, 1993, and revised Rule 311, adopted August 2, 1993. 
Note: These rules are restored as elements of the State of Arizona Air 
Pollution Control Implementation Plan effective September 3, 1997.
* * * * *
    (88) Plan revisions were submitted on May 7, 1997 by the Governor's 
designee.
    (i) Incorporation by reference.
    (A) Maricopa County Environmental Services Department.
    (1) Rule 310, adopted September 20, 1994.
    (2) Resolution To Improve the Administration of Maricopa County's 
Fugitive Dust Program and to Foster Interagency Cooperation, adopted 
May 14, 1997.
    (B) The City of Phoenix, Arizona.
    (1) A Resolution of the Phoenix City Council Stating the City's 
Intent to Work Cooperatively with Maricopa County to Control the 
Generation of Fugitive Dust Pollution, adopted April 9, 1997.
    (C) The City of Tempe, Arizona.
    (1) A Resolution of the Council of the City of Tempe, Arizona, 
Stating Its Intent to Work Cooperatively with Maricopa County to 
Control the Generation of Fugitive Dust Pollution, adopted March 27, 
1997.
    (D) The Town of Gilbert, Arizona.
    (1) A Resolution of the Mayor and the Common Council of the Town of 
Gilbert, Maricopa County, Arizona, Providing for the Town's Intent to 
Work Cooperatively with Maricopa County, Arizona, to Control the 
Generation of Fugitive Dust Pollution, adopted April 15, 1997.
    (E) The City of Chandler, Arizona.
    (1) A Resolution of the City Council of the City of Chandler, 
Arizona, Stating the City's Intent to Work Cooperatively with Maricopa 
County to Control the Generation of Fugitive Dust Pollution, adopted 
March 27, 1997.
    (F) The City of Glendale, Arizona.
    (1) A Resolution of the Council of the City of Chandler, Maricopa 
County, Arizona, Stating Its Intent to Work Cooperatively with Maricopa 
County to Control the Generation of Fugitive Dust Pollution, adopted 
March 25, 1997.
    (G) The City of Scottsdale, Arizona.
    (1) A Resolution of the Scottsdale City Council Stating the City's 
Intent to Work Cooperatively with Maricopa County to Control the 
Generation of Fugitive Dust Pollution, adopted March 31, 1997.
    (H) The City of Mesa, Arizona.
    (1) A Resolution of the Mesa City Council Stating the City's Intent 
to Work Cooperatively with Maricopa County to Control the Generation of 
Particulate Air Pollution and Directing City Staff to Develop a 
Particulate Pollution Control Ordinance Supported by Adequate Staffing 
Levels to Address Air Quality, adopted April 23, 1997.
* * * * *
    3. Section 52.123 is amended by adding paragraph (f) to read as 
follows:


Sec. 52.123  Approval status.

* * * * *
    (f) Maricopa County PM-10 Nonattainment Area (Phoenix Planning 
Area). (1) Plan for Attainment of the 24-hour PM-10 Standard--Maricopa 
County PM-10 Nonattainment Area (May, 1997) submitted by the Arizona 
Department of Environmental Quality on May 7, 1997.
    (i) The Administrator approves the provisions for implementing RACM 
and BACM for the significant source categories of disturbed cleared 
areas, earth moving, and industrial haul roads.
    (ii) The Administrator approves the attainment and reasonable 
further progress demonstrations for the Maryvale PM-10 monitoring site 
and Salt River PM-10 monitoring site.
    (iii) The approvals in paragraphs (f)(1)(i) and (ii) of this 
section are applicable only to the plan identified in paragraph (f)(1) 
of this section and do not constitute the Administrator's final 
decision as to the State's full compliance with the requirements of 
Clean Air Act sections 189(a)(1)(C) and 189(b)(1)(B) for RACM and BACM 
and sections 189(a)(1)(B), 189(b)(1)(A) and 189(c)(1) for attainment 
and reasonable further progress.
    4. Section 52.124 is amended by adding paragraph (b) to read as 
follows:


Sec. 52.124  Part D disapproval.

* * * * *
    (b) Maricopa County PM-10 Nonattainment Area (Phoenix Planning 
Area). (1) Plan for Attainment of the 24-hour PM-10 Standard--Maricopa 
County PM-10 Nonattainment Area (May, 1997) submitted by the Arizona 
Department of Environmental Quality on May 7, 1997.

[[Page 41865]]

    (i) The Administrator disapproves the provisions for implementing 
RACM and BACM for the significant source categories of agricultural 
fields, agricultural aprons, vacant lands, unpaved parking lots, and 
unpaved roads.
    (ii) The Administrator disapproves the attainment and reasonable 
further progress demonstrations for the Gilbert PM-10 monitoring site 
and West Chandler PM-10 monitoring site.
    (iii) The disapprovals in paragraphs (f)(1)(i) and (ii) of this 
section are applicable only to the plan identified in paragraph (f)(1) 
of this section and do not constitute the Administrator's final 
decision as to the State's full compliance with the requirements of 
Clean Air Act sections 189(a)(1)(C) and 189(b)(1)(B) for RACM and BACM 
and sections 189(a)(1)(B), 189(b)(1)(A) and 189(c)(1) for attainment 
and reasonable further progress. Therefore such disapprovals do not 
constitute state failures for the purpose of triggering sanctions under 
Sec. 179(a) of the Clean Air Act.

[FR Doc. 97-20470 Filed 8-1-97; 8:45 am]
BILLING CODE 6560-50-U