Approval and Promulgation of Implementation Plans; Arizona- Phoenix Nonattainment Area; PMINF10

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[AZ31-1-6531; FRL-5173-8]

Approval and Promulgation of Implementation Plans; Arizona-

Phoenix Nonattainment Area; PM10

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is finalizing the approval of a revision to the Arizona

State Implementation Plan (SIP) proposed in the Federal Register on

July 28, 1994. The revision was submitted to EPA by Arizona to fulfill

the State's obligation to revise its SIP to meet the PM10

(particulate matter less than or equal to 10 microns in aerodynamic

diameter) ``moderate'' area planning requirements of the Clean Air Act

(CAA or Act). This approval action will incorporate this revision into

the federally approved SIP. The intended effect of approving this

revision is to regulate emissions of PM10 in the Phoenix Planning

Area (PPA). The revised SIP controls PM10 emissions from sources

including, but not limited to, paved roads, construction and demolition

activities, unpaved parking areas and roads, nonmetallic mineral mining

and processing facilities, open burning activities, uncovered haul

trucks and farming operations. Thus, EPA is finalizing the approval of

this revision into the Arizona SIP under provisions of the CAA

regarding EPA action on SIP submittals, SIPs for national primary and

secondary ambient air quality standards and plan requirements for

nonattainment areas.

EFFECTIVE DATE: This action is effective on May 10, 1995.

ADDRESSES: Copies of the SIP revision are available for public

inspection at EPA's Region IX office during normal business hours.

Copies of the submitted SIP revisions are available for inspection at

the following locations:

Plans Development Section (A-2-2), Air and Toxics Division, U.S.

Environmental Protection Agency, Region IX, 75 Hawthorne Street, San

Francisco, CA 94105.

Environmental Protection Agency, Air Docket (6102), 401 ``M'' Street

SW., Washington, DC 20460.

Arizona Department of Environmental Quality, 3033 North Central Avenue,

Phoenix, AZ 85012.

FOR FURTHER INFORMATION CONTACT: Robert Pallarino, (415) 744-1212.

SUPPLEMENTARY INFORMATION: [[Page 18011]]

I. Background

A. CAA Requirements

On the date of enactment of the 1990 Clean Air Act Amendments,

PM10 areas, including the PPA, meeting the conditions of section

107(d) of the Act were designated nonattainment by operation of law.

Once an area is designated nonattainment, section 188 of the Act

outlines the process for classification of the area and establishes the

area's attainment date. In accordance with section 188(a), at the time

of designation, all PM10 nonattainment areas were initially

classified as ``moderate'' by operation of law. See 40 CFR 81.303

(1993). A moderate area may subsequently be reclassified as ``serious''

if at any time EPA determines that the area cannot practicably attain

the PM10 NAAQS by the applicable attainment date for moderate

areas, December 31, 1994. Moreover, a moderate area is reclassified by

operation of law if the area is not in attainment after the applicable

attainment date, which is December 31, 1994 for the PPA. EPA is

required to make a determination and provide public notice regarding

whether the area has attained within six months following the

attainment date. See Section 188(b), 42 U.S.C. 7513(a).

The air quality planning requirements for moderate PM10

nonattainment areas are set out in subparts 1 and 4 of title I of the

Act. EPA has issued guidance in its General Preamble describing EPA's

views on how the Agency will review SIPs and SIP revisions submitted

under title I of the Act, including those containing moderate PM10

nonattainment area SIP provisions. 57 FR 13498 (April 16, 1992); 57 FR

18070 (April 28, 1992). The General Preamble provides a detailed

discussion of the EPA's interpretation of the Title I requirements.

States with initial moderate PM10 nonattainment areas were

required to submit, among other things, the following provisions by

November 15, 1991:1

\1\There are additional submittals associated with moderate

PM10 nonattainment plans, such as a permit program for the

construction of new and modified major stationary sources and

contingency measures. See sections 189(a) and 172(c)(9). These

submittals were required to be submitted in 1992 and 1993,

respectively, and are not the subject of today's action which

addresses only those plan provisions required to be submitted on

November 15, 1991.

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1. Provisions to assure that reasonably available control measures

(RACM) (including such reductions in emissions from existing sources in

the area as may be obtained through the adoption, at a minimum, of

reasonably available control technology (RACT)) shall be implemented no

later than December 10, 1993;

2. Either a demonstration (including air quality modeling) that the

plan will provide for attainment as expeditiously as practicable but no

later than December 31, 1994, or a demonstration that attainment by

that date is impracticable;

3. Pursuant to section 189(c)(1), for plan revisions demonstrating

attainment, quantitative milestones which are to be achieved every 3

years and which demonstrate reasonable further progress (RFP) toward

attainment by December 31, 1994;2 and

\2\As discussed in the Federal Register notice proposing

approval of this plan, the PM10 plan for the PPA does not

demonstrate attainment by December 31, 1994, but rather includes the

alternative demonstration that attainment by that date is

impracticable. Therefore, section 189(c) does not apply. However, as

discussed further in this notice, areas demonstrating that

attainment is impracticable are required by section 172(c)(2) to

demonstrate RFP. See Section IV. of this Notice, ``Reasonable

Further Progress''.

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4. Provisions to assure that the control requirements applicable to

major stationary sources of PM10 also apply to major stationary

sources of PM10 precursors, except where the Administrator

determines that such sources do not contribute significantly to

PM10 levels which exceed the NAAQS in the area.

In today's rulemaking action, EPA is taking final action to approve

Arizona's moderate PM10 SIP revision for the PPA, which includes

the State's demonstration that attainment of the PM10 NAAQS by

December 31, 1994, is impracticable for the PPA. EPA is also announcing

its intention to reclassify the PPA as a serious nonattainment area

pursuant to section 188(b)(2). However, EPA is not making a finding as

to whether the PPA has attained the PM10 NAAQS in today's action,

but, as discussed elsewhere in this Notice, will be doing so in a

separate action in the coming months. See Section III. Once EPA

determines the PPA has not attained the PM10 NAAQS, the area will

be reclassified to serious by operation of law.

B. Proposed SIP Approval

EPA proposed approval of the moderate area PM10 SIP revision

for the PPA on July 28, 1994 (59 FR 38402). EPA's proposed approval was

based on a preliminary finding that the State's submittal meets the

requirements of the Act, including: (1) an inventory of all sources of

PM10 in the nonattainment area; (2) provisions to implement RACM

by December 10, 1993; and (3) a demonstration that attainment of the

PM10 NAAQS by the moderate area attainment date, December 31,

1994, is impracticable.

EPA proposed simultaneously to approve Maricopa County Rule 310--

Open Fugitive Dust Sources, 311--Particulate Matter from Process

Industries, 314--Open Outdoor Fires, and 316--Nonmetallic Mineral

Mining and Processing, as new rules the State adopted as RACM for the

PPA. EPA also proposed to reclassify the PPA as a serious area and

invited public comment on whether final action should occur under

section 188(b)(1) or 188(b)(2) of the CAA.

II. Today's Action

In today's document, EPA is taking final action to approve the

moderate area PM10 state implementation plan revision for the PPA.

The SIP revision for the PPA was submitted by the State of Arizona on

August 11, 1993 and March 3, 1994. Maricopa County Rule 314 was adopted

by the State and submitted to EPA on January 4, 1990. The State also

submitted a revised version of Maricopa County Rule 310--Open Fugitive

Dust Sources on December 19, 1994. The County revised this rule to

delete provision 221.9 of the Rule as requested by EPA. See 59 FR

38407, July 28, 1994. Specifically, EPA is approving and incorporating

by reference into the SIP the MAG 1991 Particulate Plan for PM10

for the Maricopa County Area and 1993 Revisions, the Revised Chapter 9

and Maricopa County Rule 311--Particulate Matter from Process

Industries and Rule 316--Nonmetallic Mineral Mining and Processing,

Maricopa County Rule 314--Open Outdoor Fires and Maricopa County Rule

310--Open Fugitive Dust Sources. EPA is also stating its intention, but

is not taking final action at this time, to reclassify the PPA under

section 188(b)(2) of the Act. EPA is not taking final action on its

proposal to reclassify the PPA under section 188(b)(1) of the Act.

III. Reclassification

As stated above, EPA is not reclassifying the PPA in this document.

However, EPA intends to propose reclassification of the PPA to a

serious area pursuant to section 188(b)(2) of the Act.

The Act provides two mechanisms for reclassifying moderate

PM10 nonattainment areas as serious PM10 nonattainment areas.

Section 188(b)(1) gives EPA the discretion to reclassify any area which

EPA determines cannot practicably attain the NAAQS by the applicable

attainment date at any time before the attainment date. In the case

[[Page 18012]] of the PPA, the CAA-mandated attainment date was

December 31, 1994. The second mechanism for reclassification, provided

by section 188(b)(2), is to make a finding after the attainment date

has passed that the area has not attained the NAAQS.

The difference between these two mechanisms involves the timing of

submittals of certain plan provisions. Under section 188(b)(1), if EPA

were to take final action on its proposal to reclassify the PPA as

serious (see 59 FR 38406, July 28, 1994) the State would be required to

submit its serious area SIP revision in two parts. Within 18 months of

the final action reclassifying the PPA, the State would be required to

submit provisions to assure the implementation of best available

control measures (BACM) no later than four years after the date of

reclassification. The State's demonstration that the plan provides for

attainment of the PM10 NAAQS by the serious area attainment date

(December 31, 2001) would have to be submitted within four years of the

date of reclassification.

Under section 188(b)(2) of the Act, if EPA makes a determination

after the moderate area attainment date has passed that the PPA has not

attained the NAAQS, then within 18 months after the date of

reclassification, the State is required to submit provisions to assure

the implementation of BACM no later than four years after the date of

reclassification and a demonstration that the plan will provide for

attainment of the PM10 NAAQS by December 31, 2001. The practical

difference in these two approaches is the timing of the submittal of

the attainment demonstration and how it affects the BACM determination.

Under section 188(b)(1), the State would initially develop its BACM

determination in the absence of an attainment demonstration with the

potential result that the chosen measures would not ultimately attain

the PM10 standards by the applicable attainment date. Such a

result, however, would not be revealed until several years later, when

the air quality modeling analysis is conducted for the attainment

demonstration. If, at that point, additional measures were found to be

necessary for the area to attain the PM10 NAAQS, new measures

would have to be developed, adopted and submitted to EPA. In contrast,

under section 188(b)(2), all the required elements of the serious area

plan including the attainment demonstration must be submitted to EPA

within 18 months of reclassification. Thus, under section 188(b)(2),

EPA believes the process of attaining the PM10 standards is

expedited.

In its notice of proposed rulemaking, EPA expressed its intent to

reclassify the PPA under section 188(b)(2) of the Act. EPA believed

that since the State originally concluded that the PPA could not

practicably attain the PM10 NAAQS by December 31, 1994 when it

developed its November 1991 plan submission and that, despite

procedural delays and plan updates culminating in the 1993 and 1994 SIP

submittals, this conclusion has not changed, the State has been on

notice for more than three years that reclassification was likely.

Under these circumstances, a delay of four years for the submission of

a serious area attainment demonstration is unwarranted. Rather, the

Agency believed that it is more appropriate to accelerate, to the

maximum extent possible, the State's submission of a complete serious

area plan to attain the PM10 NAAQS.

Notwithstanding the reasons above, EPA stated in its proposed

rulemaking that there could be valid reasons advanced for reclassifying

the PPA under section 188(b)(1). Therefore, EPA proposed to reclassify

the PPA using its discretionary authority under section 188(b)(1). EPA

stated its intent to finalize the reclassification under section

188(b)(1) only if it received compelling arguments from commenters. EPA

received comments on the issue of reclassification from the Arizona

Department of Environmental Quality (ADEQ), Maricopa Association of

Governments (MAG), Maricopa County Environmental Services Department

(MCESD), Arizona Department of Transportation (ADOT), and Arizona

Center for Law in the Public Interest (ACLPI). The comments from ADEQ,

MAG, MCESD, and ADOT all encouraged EPA to reclassify the PPA

immediately under section 188(b)(1). These commenters were concerned

that the State's ability to complete the required technical elements of

the serious area SIP revision, particularly an improved and updated

emission inventory and an accurate air quality analysis including air

quality modeling, would require the longer submittal time for a

demonstration of attainment afforded under section 188(b)(1) of the

Act. Many of the commenters also argued that taking final action to

reclassify the PPA before the moderate area attainment date would

expedite the air quality benefits which would be provided by the

serious area plan since the BACM implementation date would occur

sooner.

EPA has not been persuaded by these comments to reclassify the PPA

under section 188(b)(1). EPA believes that the State has been aware for

a number of years that, even taking into consideration the

implementation efforts it has now undertaken in complying with the

PM10 Moderate area planning requirements, that it was

impracticable to demonstrate attainment of the PM10 NAAQS by

December 31, 1994. Thus, EPA does not believe the State has provided

any valid basis to delay submittal of an attainment demonstration by

four years. Furthermore, the schedule for developing and submitting the

technical elements of the serious area SIP revision is no different

than the schedule for submitting a complete SIP revision for areas

designated nonattainment after the passage of the 1990 CAA amendments.

Under section 189(a)(2)(B) these areas are required to submit SIP

revisions within 18 months after the date they are redesignated. The

requirements for developing the technical elements of a serious area

SIP are not substantially different from those for a moderate area.

Regarding the BACM implementation date, the Act simply states that

BACM is to be implemented no later than four years after

reclassification to serious. Under the overall scheme of the Act, the

State is certainly permitted and, in fact, encouraged to implement BACM

on as expeditious a schedule as practicable before the four-year

deadline.

EPA also notes that ACLPI opposed reclassification of the PPA under

188(b)(1) because it would have the effect of rewarding the State's

delay in preparing its PM10 SIP by giving the State four years

instead of 18 months to submit its serious area plan revision. However,

EPA is not taking final action to reclassify the PPA under section

188(b)(1). For the reasons stated above, EPA believes that

reclassification under section 188(b)(2) is the appropriate action to

take in this case. EPA will be reviewing the PM10 monitoring data

for the PPA and will make an official determination of whether the PPA

has attained the PM10 NAAQS by June 30, 1995 or sooner. To

demonstrate attainment of the PM10 NAAQS by the applicable

attainment date (December 31, 1994), the PPA would need to show that it

has had no violations of the PM10 standards, 24 hour and annual,

in the past three years (1992, 1993, and 1994). 40 CFR part 50,

appendix K. The State recorded violations of both standards in 1992 and

1993.

IV. Reasonable Further Progress

Section 172(c)(2) of the Act states that nonattainment area plans

shall require [[Page 18013]] reasonable further progress (RFP). RFP is

defined by section 171(1) as ``such annual incremental reductions in

emissions of the relevant air pollutant as are required by this part or

may reasonably be required by [EPA] for the purpose of ensuring

attainment of the applicable [NAAQS] by the applicable date.'' However,

there is a gap in the statute in that the PM10 specific provisions

of the Act do not clearly specify when and in what manner states

containing PM10 nonattainment areas that ultimately demonstrate it

is impracticable to attain the NAAQS by the Moderate area deadline,

such as the PPA, which is the subject of this document, must

demonstrate they have met the RFP requirement. While section 189(c)(1)

of the Act requires PM10 SIP revisions to contain quantitative

milestones which are to be achieved every 3 years until the area is

redesignated attainment and which must also demonstrate reasonable

further progress, that section, by its explicit terms, only applies to

areas with ``plan revisions demonstrating attainment.'' However, while

it appears that the Act does not provide specifically for a

quantitative milestone reporting requirement showing RFP is met for

areas that demonstrate it is impracticable to attain the PM10

NAAQS by the applicable deadline, EPA nonetheless believes, based on

the general nonattainment area provisions regarding RFP as well as the

overall purpose and structure of Title I and Part D of the Act, that

such areas are not thereby relieved of the obligation to periodically

demonstrate that they are meeting the requirement for RFP.

Consequently, for purposes of implementing the RFP requirement for such

areas, EPA believes that where the language in section 171(1) indicates

that the purpose of the RFP reductions is to ensure ``attainment of the

applicable [NAAQS] by the applicable [attainment] date,'' the

applicable attainment date for areas demonstrating that it is

impracticable to attain would be the date set by section 188(c) when

the area is reclassified as serious. Similarly, since the Act does not

explicitly provide for states with PM10 nonattainment areas which

demonstrate it is impracticable to attain to submit periodic reports

demonstrating that RFP is being met, such as is required under section

189(c)(1) for PM10 areas which demonstrate attainment, EPA

believes it may invoke the discretionary authority provided the Agency

under section 110(p) of the Act to require the submittal of such

reports. That section states that ``any State shall submit'' such

reports as EPA may require, and on such schedules as EPA may prescribe,

providing information on specific data but also including ``any other

information [EPA] may deem necessary to assess the development

effectiveness, need for revision, or implementation of any plan or plan

revision required under this Act.'' The initial RFP report for such

areas is to be included in the SIP submittal containing the area's

demonstration of impracticability, and should show that even though the

emissions reductions achieved through the implementation of all RACM

may not be enough to enable the area to demonstrate attainment by the

Moderate area deadline of December 31, 1994, such implementation has

resulted in ``incremental reductions'' in emissions of PM10 as the

RFP definition in section 171(1) specifies. Once the area has been

reclassified, subsequent RFP report submittals will be timed to reflect

emissions reductions which will be achieved due to the implementation

of BACM. In summary then, EPA's policy is that the requirement to

submit periodic reports demonstrating that RFP (as defined in section

171(1)) is being met applies equally to PM10 nonattainment areas

that demonstrate attainment by the applicable deadline and to such

areas that demonstrate it is impracticable to attain by such date; for

the former areas the requirement applies pursuant to sections 189(c)(1)

and 172(c)(2), for the latter areas the requirement applies pursuant to

sections 172(c)(2) and 110(p). As described in greater detail elsewhere

in this document, the Phoenix Planning Area, has provided information

along with its impracticability demonstration, which proves to EPA's

satisfaction that it has met the requirement to demonstrate RFP.

Finally, the discussion in this document regarding the demonstration of

RFP in PM10 nonattainment areas which demonstrate that attainment

by the applicable attainment date is impracticable represents EPA's

preliminary guidance on this issue, and is intended to clarify the

confusion created by omissions in the Act and in prior EPA guidance.

EPA also intends, in the very near future, to issue more comprehensive

guidance on this issue.

V. Response to Comments on Proposed SIP Approval

Only ACLPI commented on EPA's proposed approval of the SIP

revision; other commenters addressed reclassification. EPA appreciates

the comments submitted by ACLPI, which are detailed and thoughtful.

Some of the comments raise difficult issues regarding the State's

compliance with complex planning requirements, which often depend on

coordination between a number of local governments. ACLPI's most

detailed comments concern the State's implementation of RACM,

particularly Transportation Control Measures (TCMs). In this document,

EPA is providing its general response to ACLPI's comments on the

implementation of RACM, and EPA is also providing very detailed

responses concerning individual TCMs and other specific measures raised

in ACLPI's comments in the Technical Support Document (TSD)

accompanying this document.

A. Technical Issues

1. Monitoring

Comment: The PM10 SIP revision for the PPA does not provide

for the establishment and operation of a PM10 monitoring network

which meets the requirements of EPA guidelines and regulations.

According to a 1992 EPA audit, the monitoring network for the Phoenix

area ``fails to meet many of the minimum CFR requirements''.

Response: EPA disagrees with the comment. The PM10 SIP

revision provides for establishing and operating a PM10 monitoring

network in the PPA which meets the requirements of EPA guidelines and

regulations. 40 CFR part 58; ``Guideline for the Implementation of the

Ambient Air Monitoring Regulations 40 CFR Part 58.'' The relevant

provisions of the PPA's monitoring network are in Appendix B, Exhibit

14 of the SIP revision. Appendix B, Exhibit 14 also discusses proposed

modifications to the network and the method by which the Maricopa

County Environmental Services Department (MCESD) will address episode

occurrences.

Since a 1992 Re-Evaluation of the Maricopa County Air Pollution

Control Program that was conducted by EPA, the MCESD has made and

documented progress to meet the requirements in 40 CFR parts 50 and 58.

The MCESD was required by the Agency to develop a Corrective Action

Plan (CAP) to address deficiencies documented in the 1992 Re-

Evaluation. The progress on the CAP is being monitored by EPA, Region

IX Air Quality Section and Compliance and Oversight Section, through

review and verification of progress reports by MCESD and visits with

the MCESD Air Monitoring Program personnel. EPA has also withheld

federal grant money to encourage the MCESD to address CAP commitments

and regulatory requirements in a timely manner. There have been

improvements by MCESD, [[Page 18014]] including revising the Quality

Assurance Program Manual (conditionally approved by Region IX pending

minor additions), revamping its entire PM10 network with new

equipment including four continuous PM10 samplers, quality

assurance training for air monitoring staff, and others.

Comment: A 1992 audit by Dames and Moore (DM) found that the

monitoring network did not have adequate numbers of neighborhood scale

and middle scale monitors, as directed by EPA guidance. Several

homogenous subregions in the area have no monitoring station or one

station. In addition, little or no monitoring is conducted within 500

meters from several major sources. DM also found that the total number

of monitoring stations is far below that required by EPA guidance.

Under EPA spatial siting guidelines, there should be approximately 94

monitoring stations in the nonattainment area. Yet the SIP shows only 9

permanent PM10 stations. DM also found that the monitoring program

was inadequately staffed.

Response: EPA does not agree with the DM audit's comments on

network adequacy, particularly concerning the necessary number of air

monitoring sites recommended by DM. EPA criteria, in 40 CFR part 58,

requires the Maricopa County network to consist of six (6) to ten (10)

National Air Monitoring Stations (NAMS). The district is also required

to operate State and Local Air Monitoring Stations (SLAMS). Part 58

does not contain a numerical requirement for SLAMS. Maricopa County's

network consists of six (6) NAMS, two (2) SLAMS, and five (5) Special

Purpose Monitoring Stations (SPMS), for a total of thirteen (13) SLAMS

(NAMS are defined as a subset of SLAMS). The network's only deficiency

is that it lacks a category (a) NAMS site with a high concentration

monitoring objective. But this deficiency is being corrected and a

special purpose monitor has been set up at the proposed location for a

Category (a) site. An EPA protocol provides that this sampler will be

run for at least one year. The data will then be evaluated to determine

if the site meets the objectives and should be proposed as a NAMS.

However, even without a category (a) site, the MCESD air monitoring

network is measuring PM10 values above the 24 hour standard.

Part 58 requirements for ambient air monitoring networks intend the

SLAMS networks to be representative of the four basic monitoring

objectives stipulated in part 58 over the air basin. See 40 CFR part

58, appendix D. Annual network reviews are requested of the districts

and evaluated by the EPA to insure it is representative of the

monitoring stations and to insure optimum use of resources. EPA,

therefore, disagrees that 94 monitoring stations should be required in

the nonattainment area.

Comment: In a May 15, 1992 letter to the State EPA stated that the

SIP must include provisions for follow-up monitoring and annual network

reviews. The State was to insure that the monitoring network in place

as of January 1, 1994, would be appropriate to evaluate attainment. EPA

also stated that the SIP revision should include a plan for

establishing PM10 episode monitoring stations. None of these

requirements have been met in the form of enforceable, funded

commitments by the State or local governments.

Response: The State has addressed these requirements in the

PM10 SIP revision for the PPA which is enforceable now on the

State level, and which will be enforceable federally once this final

notice becomes effective. Appendix B, Exhibit 14 contains additional

information on the County's air quality surveillance system. Appendix

B, Exhibit 15 contains the County's Rule 510--Air Quality

Standards--which provides for the establishment of pollutant monitoring

in accordance with EPA guidance and Federal regulations. Appendix B,

Exhibit 16 contains the County's Rule 600 which addresses emergency

episodes. Appendix B, Exhibit 17 contains further information on the

State's procedures for the prevention of emergency episodes.

Comment: The technical support document accompanying EPA's proposed

rulemaking asserts that the SIP provides for correction of the

monitoring deficiencies by January 1, 1994. We ask EPA to identify

precisely where the SIP shows a legally enforceable commitment to this

effect, and where the SIP shows a commitment of financial resources to

complete the job. Moreover, because the January 1, 1994 date has long

since passed, the correction of deficiencies should now be complete. We

ask EPA to indicate where the State has documented actual correction of

the deficiencies, if this has in fact occurred.

Response: As discussed in the preceding response, Maricopa County

has made documented progress in meeting all of the Federal air quality

monitoring requirements. The appendices to the PM10 plan, cited

above, provide specific information on the County's progress in

correcting deficiencies with the monitoring network.

2. Emission Inventory

Comment: The State's emission inventory is not accurate or current

as required by the CAA.

Response: EPA disagrees with this comment and believes that the

emissions inventory is accurate to within an acceptable degree of

uncertainty. The State followed EPA-recommended emissions inventory

procedures in use at the time of inventory preparation. A degree of

uncertainty is particularly associated with PM10 inventories

because PM10 emissions are especially time- and place-specific.

Emission factors from a study in one area may differ for another area.

PM10 emissions also vary with activity levels and there are many

activities, such as residential wood burning, for which there has been

little accurate quantification. EPA recognizes that there are some

differences between the emissions inventory fractions estimated from

usual inventory methods and the source proportions determined from

Chemical Mass Balance (CMB) modeling. However, EPA does not consider

these differences to invalidate the inventory. The monitored results

used in the CMB analysis reflect differences in distance, dispersion,

and deposition of the emissions from various PM10 sources. A

source's contribution at a particular monitor is not expected to be in

the same proportion as its contribution to the area's total emissions.

This explains the inventory/CMB discrepancies.

Furthermore, accuracy of the emissions inventory is not critical to

demonstrating impracticability of attainment. This is because a

demonstration of impracticability may be based on the CMB apportionment

results and not specifically on the emissions inventory. The inventory

total is used only as a normalization scaling factor. EPA may have

reached a different conclusion if, for example, the State sought to

rely on a dispersion model, which requires a more accurate emissions

inventory, instead of the CMB receptor model. However, based on the

selected modeling, EPA believes that the inventory is sufficiently

accurate to comply with the requirements of the Act and, more

specifically, to serve as the basis for the demonstration of

impracticability.

3. Modeling

Comment: The SIP does not meet the requirements of the Act and EPA

guidance for an adequate modeling analysis.

Response: EPA disagrees with this comment. The State's modeling

[[Page 18015]] complies with EPA guidelines, which allow for a receptor

model such as CMB even though a dispersion model is recommended when

possible. See Memorandum from John Calcagni, ``PM10 SIP

Demonstrations Policy for Initial Moderate Areas'' (March 4, 1991).

EPA recognizes that the State attempted to validate a dispersion

model but was unsuccessful, in large part because of the degree of

spatial and temporal accuracy required in the emissions inventory for

use as input to a dispersion model. EPA believes that the State

provided a reasonable level of effort to develop its dispersion model.

Because it failed, however, the State is justified (and provided its

justification in the SIP revision) in using a CMB receptor model. EPA

has determined that the State's modeling complies with EPA guidelines.

EPA also anticipates the PPA will be reclassified as a serious

area. Reclassification will provide additional time for the State to

improve its modeling. When the State ultimately seeks to make an

attainment demonstration, EPA will apply more stringent criteria for

the spatial and temporal accuracy of the emissions inventory,

corroborating models, and treatment of secondary particulates.

Nevertheless, EPA believes that the modeling submitted by the State in

this PM10 SIP revision complies with the requirements and guidance

established by EPA for a moderate area SIP revision and demonstration

of impracticability.

Comment: EPA's proposed finding that PM10 precursors do not

contribute significantly to PM10 levels that exceed the NAAQS in

the PPA was made without any objective standard against which to

measure significance. EPA's proposed action on this issue is arbitrary

and capricious.

Response: EPA disagrees with this comment. EPA recognizes that on

individual sampling days there were detectable contributions of one

PM10 precursor, secondary ammonium nitrate. Yet the average

overall contribution of secondary ammonium nitrate was less than five

percent of the total annual inventory. See 1989-1990 Phoenix PM10

Study, Volume II: Source Apportionment, DRI, April 12, 1991, p. S-2.

This magnitude of contribution is not significant for purposes of this

action, although EPA acknowledges that such a contribution might

warrant further attention if the State were attempting to submit an

attainment demonstration for the 24-hour NAAQS. EPA believes that a

contribution of less than five percent secondary ammonium nitrate is

within the degree of uncertainty and is near the ``noise'' level for

CMB results.

In general, because of the complexity of the chemistry involved,

there is no EPA-recommended method and no scientific consensus for

dealing with secondary particulates. A number of PM10 areas have

dealt with this problem by assuming that secondary particulates are

roughly proportional (or scale) to emissions of primary particulates.

EPA believes that in the absence of better scientific or technical

information, including better EPA guidance, this approach is

reasonable. Consistent with this approach, the PPA scaled down their

total PM10 emissions inventory to exclude the contributions from

PM10 precursors. Indeed, if the PPA had included the contributions

from PM10 precursors, this would have resulted in the recording of

proportionately higher concentrations of PM10 in excess of the

NAAQS. Therefore, if the PPA had explicitly accounted for the

contribution of PM10 precursors, the State's conclusion that

attainment is impracticable would be strengthened, not weakened.

4. Mobile Source Budget

Comment: ACLPI states that in order to determine conformity of

transportation plans, projects, and programs with this SIP, a mobile

source emission budget must be identified.

Response: EPA does not agree that the State was required to

identify a mobile source emission budget. The moderate area SIP

revision for the PPA demonstrates that attainment of the PM10

NAAQS is impracticable by December 31, 1994. Mobile source emission

budgets are only required to be identified in SIP revisions which

demonstrate attainment. The preamble to EPA's transportation conformity

rule states:

Some moderate PM10 nonattainment areas may have submitted

SIPs which demonstrate that the area cannot attain the PM10

standard by the applicable attainment date. These areas have been or

will be reclassified as serious areas under section 188(b) of the

Clean Air Act. Such SIPs which do not demonstrate attainment do not

have budgets and are not considered control strategy SIPs for the

purposes of transportation conformity.

58 FR 62196, November 24, 1993.

Thus, EPA's transportation conformity rule explicitly contemplated

and determined that PM10 areas demonstrating impracticability,

like the PPA, would not have provided for and would not be required to

identify a mobile source emission budget until an approvable attainment

demonstration is submitted.

B. Demonstration of Impracticability

Comment: The State's demonstration of the impracticability of 1994

attainment is contrary to both the language and purpose of the Act. The

plain thrust of sections 188 and 189, in combination with section 172,

is that states should make every effort to attain by 1994. Rather than

searching for combinations of control measures that would produce

timely attainment, the state merely lists 13 control measures, asserts

that they are insufficient to attain by 1994, and then ``finds'' that

impracticability has been demonstrated.

Response: EPA disagrees. As discussed throughout this document,

including in relevant responses to comments, EPA has determined that

Arizona has implemented all RACM, and that the correct number of

implemented measures is 67. EPA has also determined that the PPA has

complied with the requirement of section 172(c)(2) that it demonstrate

it is meeting RFP, by showing a measurable increment of PM10

reductions between the baseline and the emissions reductions achieved

through implementation of all RACM. EPA believes, therefore, that

Arizona's SIP submittal does not contain mere assertions, but

appropriate and acceptable demonstrations that are consistent, not only

with the criteria contained in EPA's guidance, but with the Act's

language and purpose as well. Again, as discussed further elsewhere in

this Notice, EPA also believes that Congress recognized that many areas

initially designated Moderate for PM10 would not be capable of

developing SIP revisions which demonstrated attainment by the

applicable attainment date. This is evident by the fact that, for

PM10, the Act also allows States to demonstrate earlier than the

applicable attainment deadline that implementation of RACM will not

provide for attainment and, thus, that attainment by the Moderate area

deadline is impracticable. Since this provision is unique to PM10

(the Act generally provides fixed attainment dates for other pollutants

which, if the area fails to meet, subjects it to a mandatory ``bump-

up''), it seems clear that the language and intent of the Act are to

first provide PM10 areas with an opportunity to attain the NAAQS

through the implementation of reasonable, but not necessarily

exhaustive, efforts (i.e. RACM), and then to provide those areas that

cannot achieve the NAAQS by the applicable attainment date with an

alternative--to demonstrate that attainment is impracticable. However,

such areas [[Page 18016]] must then go through a second planning effort

which will require the implementation of more stringent measures, i.e.

BACM.

Comment: ACLPI commented that the State's demonstration of

impracticability is deficient because it fails to address the 24 hour

standard.

Response: EPA disagrees that the impracticability of meeting both

standards must be demonstrated. The PPA cannot be redesignated to

attainment for PM10 until the State can demonstrate that the SIP

provides for attainment of both the annual and the 24-hour NAAQS.

Conversely, if the SIP demonstrates that even with the implementation

of RACM it cannot attain any one of the standards (annual or 24-hour)

by December 31, 1994, then it has demonstrated that PM10

attainment is impracticable. As an additional matter, it should be

noted that the PPA is proportionately farther above the 24-hour NAAQS

than it is above the annual NAAQS. Thus, given that the

impracticability of attaining the annual NAAQS has been demonstrated,

EPA agrees with the State's conclusion that attaining the more

difficult 24-hour NAAQS would likely be shown to be similarly

impracticable.

Comment: ACLPI commented that EPA should not evaluate

practicability from the present point in time: i.e., whether attainment

by December 31, 1994 is now practicable. The issue is whether timely

attainment would have been practicable had the state implemented all

RACM as expeditiously as practicable, and no later than December 10,

1993. ACLPI also states that, based on the decision in Delaney v. EPA,

898 F. 2d 687 (1990), the state would be obligated to provide for

attainment as soon as possible if achievable via implementation of RACM

as expeditiously as practicable.

Response: EPA is concluding in this action that Arizona has met the

Act's requirement to implement all RACM by December 10, 1993. EPA is

also concluding that the State has demonstrated that attainment of the

PM10 NAAQS by December 31, 1994, is impracticable even with timely

implementation of all RACM. EPA therefore believes that the detailed

explanations in this notice, including those contained in other

relevant responses to comments, and in the accompanying technical

support document should adequately address the issue raised by this

comment. EPA further believes that the requirements that are relevant

to consider are those contained in the CAA, as amended in 1990, and not

statements taken from the Delaney opinion, which was construing

requirements under the CAA as amended in 1977. As stated previously in

this document, sections 172(c) and 189(a)(1)(C) when read together

require the implementation of all RACM as expeditiously as practicable

but no later than December 10, 1993. Additionally, section 189(a)(1)(B)

requires either a demonstration that the plan provides for attainment

by December 31, 1994 or a demonstration that attainment by that date is

impracticable. Since EPA believes both that the RACM implementation

requirement has been met and that an acceptable demonstration of

impracticability has been provided by the State, no further response is

required.

C. RACM

Comment: ACLPI commented generally that the SIP, EPA Guidance and

public comments identified 161 potential measures as RACM, but that the

revised PM10 SIP rejected all but 13 of the measures without

providing adequate justification. Similarly, the state adopted only one

new transportation control measure, while failing to adopt, without

explanation, every other potentially available TCM.

Response: The general and detailed comments by ACLPI concerning

RACM raise difficult issues concerning the State planning requirements,

and EPA appreciates the time and thought that ACLPI has contributed to

this process. However, ACLPI has misunderstood the number of measures

that the State implemented or rejected as RACM. The revised PM10

SIP did not reject all but 13 measures from the list of possible RACM.

As discussed below and in substantial detail in the accompanying TSD,

the State has implemented all possible RACM (in some cases, by

demonstrating that partial implementation of a measure is all that was

reasonable to implement by December 10, 1993) and has provided EPA with

a reasoned justification for the rejection of the remaining measures as

not constituting RACM.

EPA disagrees with ACLPI regarding its RACM interpretation as it

relates to transportation control measures (TCMs). In its comments

regarding whether the State should have considered various proposed

TCMs to be reasonably available, ACLPI asserts that the Court of

Appeals for the Ninth Circuit held in Delaney v. EPA, ``that TCMs

listed in section 108 of the Act are presumed to be reasonably

available.'' ACLPI goes on to argue that ``Congress adopted and

endorsed this decision in the 1990 Clean Air Act amendments,'' and

cites for this proposition 136 Cong. Rec. S16971 (daily ed. Oct. 27,

1990). In reliance on these claims, ACLPI concludes that Arizona ``has

failed to rebut the [presumption regarding the] availability of the

section 108 measures in the instant SIP, and therefore the SIP must be

rejected.'' EPA disagrees with both assertions and with the conclusion

ACLPI derives from them as well. In the General Preamble (57 FR 13560-

13561) EPA presents a detailed discussion of its interpretation of the

RACM requirement, including implementation of TCMs. EPA continues to

stand by that interpretation and the General Preamble discussion is

explicitly referenced herein as forming part of the justification for

the action being taken in this document.

The portion of that discussion that relates to TCMs acknowledges

that in pre-amended Act guidance EPA created a presumption that all of

the TCMs listed in section 108(f) were RACM for all areas, and required

areas to specifically justify a determination that any measure was not

RACM based on local circumstances. However, EPA then explicitly

repudiated that earlier guidance, explaining that, based on its

experience in implementing TCMs in subsequent years, local

circumstances varied to such a degree that it was inappropriate to

presume that all of the measures listed in section 108(f) were per se

reasonably available for all nonattainment areas. See 44 FR 20372-20375

(April 4, 1979). Under EPA's revised guidance, all states are required,

at a minimum, to address the section 108(f) measures, and where such a

measure is determined to be reasonably available to implement it in

accordance with section 172(c)(1).

With respect to Delaney, the General Preamble states EPA's belief

that the court did not hold, as ACLPI claims, that the statute required

the Agency to interpret the RACM requirement to create a presumption

that all TCMs are reasonably available. Instead, the court held that

EPA itself had created such a presumption and, therefore, was bound to

apply its own then-applicable 1979 RACM guidance. An administrative

agency is permitted to revise or alter prior guidance so long as that

guidance continues to represent a reasonable interpretation of the

statutory requirement. Nothing in the court's decision precluded EPA

from revising its own guidance based on later experience in

implementing TCMs. EPA also believes that the Senate managers'

statement endorsing the Agency's 1979 RACM guidance as construed by the

Delaney court reflected the view of several legislators who had wanted

the Senate Committee bill to require that all section 108(f) measures

be implemented [[Page 18017]] in severe nonattainment areas. However,

the final version of the Senate bill did not adopt this position.

Consequently, any subsequent statements by any legislators that appear

to consider the interpretation relating to TCMs in EPA's 1979 RACM

guidance as still being applicable post-1990 could not be said to

reflect the views of the Congress as a whole, and thus should not be

accorded weight.

Sections 172(c) and 189(a)(1)(C), along with relevant EPA guidance,

require the State to implement all RACM provisions in its moderate area

plan to reduce PM10 emissions. EPA's proposed approval of the

revised PM10 SIP concluded that there was an initial list of 161

potential RACM. See 59 FR 38404. EPA has determined that the State

implemented 67 of those measures as RACM. Of the remaining 94 potential

RACM, 62 measures were duplicates of other measures. Finally, EPA

believes that the State acted in accordance with Agency guidance in

determining that the remaining 32 measures were not in fact, reasonably

available because either; (1) The source made a de minimis contribution

of PM10 or (2) the measure was rejected on the basis of economic

or technological infeasibility. Thus, EPA has determined that the State

has satisfied its moderate area RACM requirements under sections 172(c)

and 189(a)(1)(C).

In some cases, RACM has been met through partial implementation of

a measure, such as doubling rather than tripling bus service or

implementing measures only in populous municipalities. The State

provided more detailed justification explaining why partial

implementation of many measures constitutes RACM in ``Summary of Local

Government Commitments to Implement Measures and Reasoned Justification

for Non-Implementation for the MAG 1991 Particulate Plan for PM10

and Select Measures from the Clean Air Act Section 108(f)'' (``MAG

Supplementary Document''). The Mag Supplementary Document was submitted

at EPA's request after EPA proposed to approve the revised PM10

SIP in an effort to respond to comments received by EPA claiming that

the SIP submittal did not contain sufficient detail regarding the

State's justification for rejecting potential RACM. The MAG

Supplementary Document has been included in the Administrative Record

for this rulemaking and, to the extent that it provides additional

detail and elaborates on the State's reasoning regarding its RACM

determination, forms, in part, a complementary basis for EPA's final

approval of the State's revised PM10 SIP, including EPA's finding

that the State complied with its obligation under Sections 172(c) and

189(a)(1)(C) to implement all RACM.

The list of 67 RACM the State has implemented includes 41 measures

that were adopted in the State's 1993 Carbon Monoxide and Ozone Plans

(``1993 CO Plan''). EPA believes that adoption and inclusion of the

measures in the 1993 CO Plan is a sufficiently meaningful and legally

binding action by the State which, moreover, constitutes compliance

with the Act's requirement to submit a plan which includes provisions

to assure that RACM is implemented no later than December 10, 1993.

ACLPI's comments on individual measures addressed in the accompanying

TSD state that certain measures have not been adopted ``in committed

form.'' For the measures in the 1993 CO Plan, EPA believes that the

State has provided adequate evidence that the plan is being implemented

and is enforceable. The State's 1993 CO plan builds upon the control

strategy developed and adopted for the MAG 1987 CO plan. Many of the

measures in the 1993 CO plan continue implementation of transportation

control measures included in the 1987 CO plan. The 1993 CO plan also

contains new control measures that were not in the 1987 CO plan. EPA is

aware that, for the most part, the State is not claiming PM10

emission reduction credits for the measures developed for their CO and

ozone plans. The PM10 SIP does take emission reduction credit for

Maricopa County's Trip Reduction Ordinance and the operation of two

alternative fueled buses. The State explained instead that reductions

from RACM in the 1987 CO Plan were calculated in the 1989 baseline

PM10 emission inventory. These CO measures may qualify as RACM

regardless of whether emissions reduction credit can be assigned, as

noted by EPA's proposed approval, stating: ``These CO measures are

included in the PM10 SIP revision because they could also reduce

particulate matter emissions.'' 59 FR 38404. EPA has not received

direct adverse comment on the proposal to include the CO measures in

the State's revised PM10 SIP as RACM, and is therefore taking

final action on that proposal. The 41 measures from the CO and Ozone

Plans that are treated as RACM in the revised PM10 SIP are listed

in the TSD, Attachment #2, for this NFRM.

In addition to RACM from the 1993 CO Plan, the State is

implementing measures required by national rulemakings. These measures

are also RACM for the moderate area PM10 SIP. For example, the

State must ensure that cleaner commercial aircraft land in the PPA

based on the federal Airport Noise Control Act, 49 U.S.C. App. 2151

(1990) (ANCA). Municipalities in the PPA are required to comply with

ANCA. Thus, even though the clean aircraft requirement is established

by ANCA, it also satisfies the State's obligation to assure

implementation of RACM. EPA believes the State may satisfy the RACM

obligation pursuant to compliance with ANCA rather than through

adoption in the revised PM10 SIP of measure No. 45, ``Replacement

of High Emitting Aircraft,'' offered in the public comments. The

accompanying TSD lists RACM which are based on national rulemakings or

emissions standards.

For diesel fuel controls, EPA believes that the State has

adequately demonstrated that partial implementation of this measure

through compliance with national diesel fuel standards is RACM, and

that the State has also justified rejecting implementing the California

diesel fuel standards as RACM. Likewise, the State's partial

implementation of a measure requiring conversion of its diesel fleet to

clean fuels constitutes RACM. The State has also partially implemented

measures regulating nonroad utility heavy duty engines and utility

engines through compliance with national standards. EPA believes that

partial implementation of this measure is all that was reasonable for

the state to implement by December 10, 1993. The implementation of

controls associated with diesel fuels and engines is discussed more

fully in the accompanying TSD. The TSD also discusses the State's

justification for rejecting as RACM an inspection and maintenance

testing program for diesel vehicles.

Comprehensive rules are another source of RACM. The State submitted

several comprehensive rules, such as Rules 310, 311, 314 and 316, that

encompass RACM that are separate from the initial list of 161 possible

measures. For example, Rule 310 addresses 13 of the 15 measures that

EPA considered to be reasonably available for the control of fugitive

dust. See 59 FR 38404. The accompanying TSD provides a more detailed

discussion of RACM for fugitive dust based on implementation of Rule

310. To control residential wood combustion, Maricopa County has

adopted a new rule, Residential Woodburning Restriction Ordinance

(RWRO), and the State has included a provision in HB 2001 that provides

a personal income tax deduction for people that purchase EPA-certified

wood heaters. The County also has a [[Page 18018]] public education and

awareness program in place to inform residents of the impacts of

residential wood combustion on air quality and public health and the

requirements of the County's woodburning restriction ordinance. These

measures cover all of the four RACM listed by EPA in its General

Preamble to address particulate matter emissions from residential wood

combustion. The State's adoption of the County's RWRO satisfies the

obligation to adopt measures to reduce emissions from residential wood

combustion. As with measures in the 1993 CO Plan, EPA believes that the

State has adopted the RWRO in sufficiently meaningful legal form to

ensure that RACM is being implemented in compliance with the Act. The

TSD also discusses this measure.

From the initial list of 161 possible RACM, EPA determined that 62

measures are duplicates of others and consequently did not require any

further consideration. These duplicate measures are also listed in the

TSD, Attachment #1.

Finally, EPA has determined that the State was justified in

rejecting 32 of the remaining measures from the list of 161 possible

RACM. These measures, which are listed in the TSD, Attachment #3, were

discussed in EPA's proposed approval, 59 FR 38404, and are not

reasonably available because they are either de minimis or economically

or technologically infeasible. Certain measures are not reasonably

available because the contribution from the source is de minimis in the

PPA, such as Public Comment No. 37 which provides for reducing

emissions from ship berthing. There are no ship berthing facilities in

the PPA. Alternatively, the State has provided reasoned justifications

to reject certain measures as RACM based on economic or technological

infeasiblity, such as railroad electrification. Those measures rejected

from the initial list of 161 possible RACM, and the justifications for

such rejections, are provided in the accompanying TSD.

For the reasons stated above, EPA has determined that the State has

satisfied its obligation under the Act to submit a plan containing

provisions to assure that RACM has been implemented by December 10,

1993, and, consistent with Agency guidance, has provided a reasoned

justification for rejecting other potential measures on grounds that

they are not RACM. The accompanying TSD provides a detailed response to

each specific measure or type of measure that was raised in ACLPI's

comments on the RACM portion of EPA's proposed approval of the State's

revised PM10 SIP. Many other measures were duplicates of measures

that were either adopted or rejected. For the remaining measures which

the State rejected, EPA has given careful consideration to ACLPI's

thorough comments. On balance, however, the State has complied with its

obligation to provide EPA with a reasoned justification for the

rejection of the remaining potential RACM.

D. RFP

Comment: The SIP fails to show RFP as required by section 172(c)(2)

of the Act. According to the SIP, emissions of PM10 increase in

1994 compared to the baseyear.

Response: EPA disagrees with the commenter's assertion that the SIP

does not demonstrate reasonable further progress in reducing PM10

emissions. While the State's demonstration showed a small reduction in

PM10 emissions from the implementation of Maricopa County's Rule

310--Fugitive Dust, EPA believes that the emission reduction that the

State associated with this rule was overly conservative. When the State

calculated the emission reduction potential for Rule 310, they only

applied the control effectiveness to the urban portions of the PPA. EPA

believes the control effectiveness should have been applied to the

entire nonattainment area since the rule applies throughout Maricopa

County which includes the entire nonattainment area. When EPA

recalculated the emission reduction benefits of the SIP's control

strategy the reduction potential equals 8,677 tons per year. The 1989

base year inventory is 40,975 tons per year and was projected to grow

to 45,981 tons per year in 1994. Therefore, the total 1994 projected

inventory after application of RACM would equal 37,304 tons per year

which shows, consistent with EPA's guidance on demonstrating RFP, which

is described in greater detail earlier in this notice, that the area

has indeed made progress in reducing emissions from the base year

total, and thus has demonstrated it has met the requirements of section

172(c)(2) for the period 1990-1994.

E. Rules

Comment: Rule 310 is not approvable because the rule does not meet

the Act's or EPA's criteria for enforceability. The rule must make

clear to whom it applies and be sufficiently specific that a source is

fairly on notice as to the standard it must meet. No threshold level of

dust generation is specified, leaving sources to guess as to when the

ordinance will be triggered.

Response: Rule 310 does specify the sources that are subject to

control. Rule 310 applies to any activity, equipment, operation and/or

man-made or man-caused condition or practice capable of generating

fugitive dust. Section 300 of the Rule further specifies the types of

activities and sources of fugitive dust that are subject to the rule's

requirements (e.g., vehicle use in open areas and vacant parcels;

unpaved parking areas/staging areas; unpaved haul/access roads;

disturbed surface areas; vacant areas; material handling operations;

material transport; haul trucks; roadways, streets and alleys; and

cattle feedlots and livestock areas). Further, as discussed in more

detail in response to the next comment, the requirements of Rule 310

are triggered if a source of fugitive dust violates either the 20%

opacity standard in Section 301 or the requirement to implement RACM in

Sections 301 through 314. Thus, any activity that causes visible

emissions in excess of 20 percent opacity or any activity that is

carried out contrary to the implementation of RACM is a violation of

Rule 310. For new sources of fugitive dust, Rule 310 requires

compliance with an approved dust control plan as implementation of

RACM, subject to approval by the control officer; existing sources of

fugitive dust are required to comply with the RACM defined in the Rule.

Comment: The standards of performance [in Rule 310] are equally

vague. The rule merely states that reasonably available control

measures must be applied. That term is in turn defined merely by

listing examples of vaguely described control steps without requiring

use of any specific measure or a specific level of effort in any

specific context. Thus, any specific level of control that the County

seeks to impose will be subject to challenge.

Response: ACLPI's comments tend to oversimplify the requirements of

Rule 310. Because of the very many different circumstances under which

fugitive dust can be generated, it would be nearly impossible for the

County to predict every situation and prescribe a specific control

measure for it. As noted above, Rule 310 contains two standards to

enforce. One standard with which all sources are required to comply is

the 20% opacity limit. The second standard is the RACM requirement. New

sources of fugitive dust are required to comply with approved dust

control plans, which become enforceable as permit conditions. For

existing sources of fugitive dust, Rule 310 addresses the variability

of sources and activities by either prescribing RACM (see, e.g.,

Section 311.2) or listing potential reasonably available fugitive dust

control measures (see, e.g., Sections 306 [[Page 18019]] & 221). Yet

Rule 310 allows a source to tailor its own control strategy to fit its

particular situation and EPA believes that such flexibility is

necessary. When the activity or situation does not involve a high

degree of variability, the measures that apply to that source are

typically more prescriptive. For example, Section 311.2, which applies

to all haul trucks operating in the PPA, sets forth specific

requirements as RACM. If haul trucks fail to implement these measures,

there is a violation of Rule 310. Even if the haul trucks comply with

Section 311.2, but still violate the 20% opacity standard, there is a

violation of Rule 310. Other sections of the rule are equally

enforceable through permit conditions. Section 303 of Rule 310 requires

that a permit application for any new source subject to Section 302 of

Rule 310 shall include a Control Plan to prevent or minimize fugitive

dust, and the Control Plan must be approved by the County Control

Officer. If the County determines through a violation of the separate

20% opacity standard that a Control Plan is not sufficient to control

fugitive dust, the responsible party is required to revise the control

plan accordingly. Thus, the County will be able to enforce the

provisions of this Rule 310 through two standards: the 20% opacity

standard and the requirement to implement RACM through a Control Plan

or as defined in the Rule.

The original version of Rule 310 that was submitted to EPA

contained a provision that EPA believed threatened the enforceability

of the rule. The original rule contained a provision (221.9) that

allowed the Control Officer to approve the use of alternative control

methods not listed in the rule. This provision has since been deleted

from Rule 310.

Comment: The State and County have not committed the necessary

resources and personnel to ensure enforcement of rules 310, 311, 314,

and 316, as required under section 110(a)(2)(E) and EPA guidance. Nor

does the SIP contain a program to provide for enforcement of any of the

SIP control strategies, as required by section 110(a)(2)(C) of the Act.

Response: The County has committed the necessary resources and

personnel to implement rules 310, 311, 314, and 316. Details on the

level of personnel and funding, as required by section 110(a)(2)(E) of

the Act, as well as enforcement strategies as required by section

110(a)(2)(C) of the Act are provided in the document ``MAG 1991

Particulate Plan for PM10 for the Maricopa County Area and 1993

Revisions, Commitments for Implementation, Volume Three'', section

entitled ``Maricopa County''.

F. Other

1. Public Comment

Comment: In the process of developing and submitting the PM10

SIP revision for Phoenix, MAG and the State have on several occasions

failed in their responsibility to seriously consider public comment

prior to adopting plans.

Response: The State has provided a section in all of its PM10

SIP submittals which includes all public comments received and the

State's responses to those comments.

2. State Assurances

Comment: The PM10 SIP does not contain, as required by section

110(a)(2)(E)(iii) of the CAA, the necessary assurances that, where the

State has relied on a local or regional government, agency, or

instrumentality for the implementation of any plan provision, the State

has responsibility for ensuring adequate implementation of such plan

provision.'' While the State contends that this requirement is met by

A.R.S. Sec. 49-406.J, the process laid out by this State statute does

not meet the plain requirements of section 110(a)(2)(E)(iii) and is

completely inconsistent with the Act's requirements for SIP

enforceability, timely implementation of control measures, and

expeditious attainment.

Response: EPA has historically adopted a rule of reasonableness in

construing the language of section 110(a)(2)(E)(iii) of the Act with

respect to the extent to which the State must show that its plan

evinces a showing of responsibility sufficient to ensure adequate

implementation of the plan's provisions by local or regional

governments. EPA, for example, does not require the State to adopt into

its own plan the local government's implementing provisions, but has

considered it sufficient for the State to describe and reference those

provisions and the accompanying descriptions of the local

municipalities intended implementation actions. The State has included

in its plan submission a copy of the Arizona Laws Relating to

Environmental Quality, Sec. 49-406. J. of which contains the assurances

required by section 110(a)(2)(E). If any person fails to implement an

emission limitation or control measure, the relevant State official is

required to issue a written finding to that effect, which may also

necessitate the holding of a conference regarding the failure with the

offending person. If a determination is made that the failure has not

been corrected, the attorney general, at the responsible official's

request, must file an action, seeking either ``a preliminary

injunction, a permanent injunction, or any other relief provided by

law.'' Section 49-407 of the Arizona Revised Statutes provides that

citizens may sue the director to perform his or her duty. While some

opportunity is provided to rectify problems short of taking legal

action, EPA does not believe this is unreasonable, nor that the

affected State officials ultimately have discretion to ignore the law's

requirements. The comment engages in some speculation, describing

several possible scenarios under which implementation by the local

authorities may not occur. Despite these concerns--which are admittedly

speculative--EPA believes, based on its experience in administering

this provision of the Act, that the relevant sections of the State's

law provides an adequate degree of assurance that the control measures

in the plan are enforceable and will be fully implemented.

VI. Executive Order 12866

The Office of Management and Budget has exempted this regulatory

action from Executive Order 12866 review.

VII. Regulatory Flexibility

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 economic impact on a substantial number of small entities.

Small entities include small businesses, small not-for- profit

enterprises, and government entities with jurisdiction over populations

of less than 50,000.

SIP approvals under section 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. Therefore, because the

federal SIP approval does not impose any new requirements, I certify

that it does not have a significant impact on small entities affected.

Moreover, due to the nature of the federal-state relationship under the

Clean Air Act, preparation of a regulatory flexibility analysis would

constitute federal inquiry into the economic reasonableness of state

action. The Clean Air 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). [[Page 18020]]

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Incorporation by

reference, Intergovernmental relations, Particulate matter, Reporting

and recordkeeping requirements.

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: February 28, 1995.

Felicia Marcus,

Regional Administrator.

Part 52, chapter I, title 40 of the Code of Federal Regulations 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 by adding paragraphs (c) (67)(i)(B),

(73), (74), and (77) and by adding and reserving paragraphs (c) (72),

(75), and (76) to read as follows:

Sec. 52.120 Identification of plan.

* * * * *

(c) * * *

(67) * * *

(i) * * *

(B) Amended Maricopa County Division of Air Pollution Control Rule

314, adopted July 13, 1988.

* * * * *

(72) [Reserved]

(73) Plan revisions were submitted on August 11, 1993 by the

Governor's designee.

(i) Incorporation by reference.

(A) The Maricopa Association of Governments 1991 Particulate Plan

for PM10 for the Maricopa County Area and 1993 Revisions, Chapters

1, 2, 3, 4, 5, 6, 7, 8, 10 and Appendices A through D, adopted August

11, 1993.

(74) Plan revisions were submitted by the Governor's designee on

March 3, 1994.

(i) Incorporation by reference.

(A) Maricopa County Division of Air Pollution Control new Rule 316,

adopted July 6, 1993, and revised Rule 311, adopted August 2, 1993.

(B) The Maricopa Association of Governments 1991 Particulate Plan

for PM10 for the Maricopa County Area and 1993 Revisions, Revised

Chapter 9 adopted on March 3, 1994.

(75) [Reserved]

(76) [Reserved]

(77) Amended regulations for the Maricopa County Division of Air

Pollution Control submitted by the Governor's designee on December 19,

1994.

(i) Incorporation by reference.

(A) Maricopa County Division of Air Pollution Control Rule 310,

adopted on September 20, 1994.

[FR Doc. 95-8215 Filed 4-7-95; 8:45 am]

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