[Federal Register Volume 63, Number 62 (Wednesday, April 1, 1998)]
[Proposed Rules]
[Pages 15920-15948]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-8061]



[[Page 15919]]

_______________________________________________________________________

Part II





Environmental Protection Agency





_______________________________________________________________________



40 CFR Part 52



Promulgation of Federal Implementation Plan for Arizona-Phoenix 
Moderate Area PM-10; Disapproval of State Implementation Plan for 
Arizona--Phoenix Moderate Area PM-10; Proposed Rule

  Federal Register/Vol. 63, No. 62/Wednesday, April 1, 1998/Proposed 
Rules  

[[Page 15920]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[FRL-5987-8]


Promulgation of Federal Implementation Plan for Arizona--Phoenix 
Moderate Area PM-10; Disapproval of State Implementation Plan for 
Arizona--Phoenix Moderate Area PM-10

AGENCY: Environmental Protection Agency (EPA).


ACTION: Proposed rulemaking and withdrawal of 1996 proposed rule.

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SUMMARY: Under the authority of section 110(c)(1) of the Clean Air Act 
(CAA or ``the Act''), EPA today proposes a federal implementation plan 
(FIP) to address the moderate area PM-10 requirements for the Phoenix 
PM-10 nonattainment area. Specifically, for both the annual and 24-hour 
PM-10 standards, EPA is proposing a demonstration that reasonably 
available control measures (RACM) will be implemented as soon as 
possible, a demonstration that it is impracticable for the area to 
attain the standards by the statutory attainment deadline and a 
demonstration that reasonable further progress (RFP) is being met. 
Pursuant to a court order, EPA's final FIP must be signed by the EPA 
Administrator no later than July 18, 1998.
    As part of its proposed RACM demonstration, EPA is proposing a 
fugitive dust rule to control PM-10 emissions from vacant lots, unpaved 
parking lots and unpaved roads, and is also proposing an enforceable 
commitment to ensure that RACM for agricultural sources will be 
proposed by September 1999, finalized by April 2000 and implemented by 
June 2000.
    In addition, in today's document, EPA is withdrawing a 1996 
proposal to restore its approval of the RACM, RFP and impracticability 
demonstrations in Arizona's moderate area PM-10 plan for the annual PM-
10 standard for Phoenix and is proposing to disapprove the 
impracticability and RACM demonstrations because those demonstrations 
do not adequately address the CAA's moderate area PM-10 requirements.
    EPA recently established a new standard for PM-2.5 and also revised 
the PM-10 standards; however, today's proposal does not address these 
new standards.

DATES: Written comments will be accepted until May 18, 1998. EPA is 
scheduled to hold a public workshop followed by a public hearing at the 
following time:
Phoenix PM-10 Moderate Area FIP Workshop and Hearing
Thursday, April 16, 1998, Workshop, 9 a.m. to 11 a.m.
Hearing, Day Session--12 noon to 4:30 p.m., Evening Session--Convenes 
at 7 p.m.

ADDRESSES: Written comments on the EPA's proposed FIP and SIP actions 
must be received by EPA at the address below on or before May 18, 1998. 
Comments should be submitted (in duplicate, if possible) to: EPA Region 
9, 75 Hawthorne Street (AIR2), San Francisco, CA 94105, Attn. Eleanor 
Kaplan, (Phone: 415-744-1287).
    The public workshop and public hearing will be held at the Phoenix 
Corporate Center Auditorium, 3003 North Central Avenue, Phoenix, 
Arizona.
    A copy of docket No. A-09-98, containing material relevant to EPA's 
proposed action, is available for review at: EPA Region 9, Air 
Division, 75 Hawthorne Street, San Francisco, CA 94105. Interested 
persons may make an appointment with Eleanor Kaplan (415) 744-1159 to 
inspect the docket at EPA's San Francisco office on weekdays between 9 
a.m. and 4 p.m.
    A copy of docket no. A-09-98 is also available to review at the 
Arizona Department of Environmental Quality, Library, 3033 N. Central 
Avenue, Phoenix, Arizona 85012. (602) 207-2217.
    Electronic availability: This document is also available as an 
electronic file on EPA's Region 9 Web Page at http://www.epa.gov/
region09.

FOR FURTHER INFORMATION CONTACT: For questions and issues regarding the 
proposed measure for agricultural fields and aprons contact John 
Ungvarsky (415) 744-1286; for questions and issues regarding the 
proposed rule for vacant lots, unpaved parking lots and unpaved roads 
contact Karen Irwin (415) 744-1903; for other general FIP and SIP 
questions and issues contact Doris Lo (415) 744-1287.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
    A. Background
    B. FIP Proposal
    C. Public Involvement in the FIP Process
II. Background
    A. Clean Air Act Requirements
    1. Designation and Classification
    2. Moderate Area Planning Requirements
    3. Federal Implementation Plan Provisions
    4. Indian Reservations
    a. EPA's FIP Obligation
    b. EPA and Tribal CAA Authority in Indian Country
    B. History of Arizona's PM-10 Plans and Related EPA Actions
    1. Arizona's Moderate Area PM-10 Plan
    2. The Microscale Plan--the 24-hour Standard
    3. EPA Actions on Arizona's Moderate Area PM-10 Plan Post-Ober 
With Respect to the Annual Standard
    C. History of PM-10 FIP Litigation in Phoenix
III. SIP Actions
    A. Proposed Disapproval of Moderate Area Plan
    B. Withdrawal of Proposal to Restore Moderate Area Plan 
Demonstrations for the Annual PM-10 Standard
IV. Moderate Area PM-10 Planning Requirements for the FIP Proposal
    A. Attainment/Impracticability Demonstration
    B. RACM/RACT Demonstration
    C. Reasonable Further Progress Demonstration
V. Summary of EPA's FIP Proposal
    A. RACM/RACT Demonstration
    1. RACT and PM-10 Precursors
    a. RACT
    b. PM-10 Precursors
    2. RACM Approach
    3. Federal Implementation Criteria
    a. Applicability to the Phoenix Area
    b. Existing RACM
    c. Legal Authority
    4. Application of Federal Implementation Criteria
    5. RACM Criteria
    a. De Minimus Source
    b. Technological Feasibility
    c. Cost of Implementation
    6. Application of RACM Criteria
    7. Proposed FIP measures
    a. Commitment for Agricultural Sector
    (1) Summary of Proposed Commitment and Approach
    (2) Background
    (3) RACM Analysis
    (4) Proposed Commitment
    (i) Discussions With Stakeholders
    (ii) BMP Approach
    (iii) FIP Proposal
    (5) FIP Replacement
    b. Rule for Unpaved Parking Lots, Unpaved Roads and Vacant Lots
    (1) Summary of Proposed Rule
    (2) Discussion
    (3) Compliance Approach
    (4) Replacement of FIP Rule
    B. Impracticability Demonstration
    1. Annual Standard
    2. 24-hour Standard
    C. Reasonable Further Progress (RFP) Demonstration
    1. Annual Standard
    2. 24-hour Standard
    a. Gilbert Monitoring Site
    b. West Chandler Monitoring Site
VI. Impact on Tribal Reservations
VII. Administrative Requirements
    A. Executive Order (E.O.) 12866
    B. Regulatory Flexibility Analysis
    1. Regulatory Flexibility Act Requirements
    2. RFA Analysis
    a. Proposed Federal Rule for Unpaved Roads, Unpaved Parking 
Lots, and Vacant Lots

[[Page 15921]]

    b. Proposed Federal Commitment for Agriculture
    c. Certification
    C. Unfunded Mandates Reform Act (UMRA)
    D. Paperwork Reduction Act

I. Executive Summary

A. Background

    The Phoenix area violates both the annual and 24-hour national 
health-based standards for particulate matter with diameters of 10 
microns or less. Consequently, Maricopa County residents continue to 
breathe unhealthy air. Particulate matter affects the respiratory 
system and can cause damage to lung tissue and premature death. The 
elderly, children, and people with chronic lung disease, influenza, or 
asthma are especially sensitive to high levels of particulate matter. 
EPA recently established a new standard for particulate matter of 
diameters of 2.5 microns or less and also revised the PM-10 standards; 
however, today's proposal does not address these new standards.
    The primary cause of the PM-10 problem is dust on paved roads 
kicked up by vehicle traffic, and windblown dust from construction 
sites, earth moving operations, unpaved parking lots and roads, 
disturbed vacant lots, agricultural fields and aprons, and other 
disturbed areas.
    When an area violates a health-based standard, the Clean Air Act 
(CAA) requires that the area be designated as nonattainment for that 
pollutant. Phoenix was originally designated and classified as a 
moderate nonattainment area for particulate matter, and Arizona was 
required to develop a plan that put into place a basic set of control 
measures. These measures did not adequately control the particulate 
pollution problem. When the area failed to attain the standards in 1994 
it was reclassified as a serious nonattainment area, and the State is 
now required to develop a plan with more comprehensive control 
measures.
    Despite the fact that the State is now working on its serious area 
plan, EPA is under court order, as a result of a lawsuit by the Arizona 
Center for Law in the Public Interest (ACLPI), to develop a moderate 
area federal implementation plan (FIP) for the Maricopa area. EPA is 
required to prepare this FIP because the State does not have an 
approved moderate area plan. Under the court order, EPA has until March 
20, 1998, to propose and July 18, 1998, to finalize the FIP.
    EPA has determined that not all the basic controls on sources 
contributing to violations of the particulate standards are in place. 
While the State has implemented a number of measures including controls 
on construction and earth moving operations, as well as a vehicle 
emission inspection and maintenance program and a clean burning 
gasoline program, there remains a need for additional emissions 
reductions. Having considered its authority and resource constraints, 
EPA is proposing two measures in the FIP for the control of dust from 
unpaved roads, parking lots, and vacant lots and agricultural fields 
and aprons. These measures will contribute to the eventual attainment 
of both the annual and 24-hour PM-10 standards.
    The State intends to submit its serious area particulate plan in 
the summer of 1998. If the plan includes control measures for the 
sources covered by the FIP and those measures are approved by EPA, the 
Agency will be able to withdraw the final FIP measures. EPA will 
continue working with the appropriate State and local agencies, as well 
as the agricultural community and the cities in the metropolitan area, 
to replace the FIP measures with State measures. EPA believes that 
clean air is likely to be achieved faster, and in greater harmony with 
local economic and community goals, if its role as a backstop is 
minimized by effective State and local actions. Because of the 
willingness of the State and local communities to identify and pursue 
solutions to their air quality problems, as evidenced by the Governor's 
Air Quality Strategies Task Force, EPA expects successful State and 
local action.

B. FIP Proposal

    EPA's FIP proposal includes a fugitive dust rule and an enforceable 
commitment in regulatory form to implement control measures for 
agricultural PM-10 sources by July 2000. These are discussed in more 
detail below. During the development of these measures, EPA held 
numerous meetings with the affected community. The purpose of these 
meetings was not only to inform the public of EPA's FIP obligation and 
the need for the Agency to develop an adequate moderate area PM-10 
plan, but also to help EPA craft air quality rules that meet both the 
public health and economic needs of this area. During all of these 
discussions there was an ongoing dialogue regarding what would be 
needed to replace the FIP with appropriate State measures. EPA 
appreciates the information that was provided by the community during 
the development phase of the proposed FIP, and the Agency will continue 
to work with the community in the development of the State's serious 
area plan. EPA is hopeful that the local planning effort will result in 
an approvable SIP that will allow EPA to withdraw its FIP.
Fugitive Dust Rule
    Although EPA has approved a Maricopa County rule (MCESD Rule 310) 
which requires controls for unpaved roads, unpaved parking lots and 
vacant lots, the County is not adequately enforcing its rule for these 
three sources due to lack of resources. Therefore, EPA has developed a 
FIP rule that proposes specific controls that will ensure adequate 
enforcement for these sources. For each source category, the FIP rule 
includes three to four control measure options and allows submittal of 
alternative control measures subject to EPA approval. In addition to 
the FIP rule, EPA is addressing the resource issue by providing 
additional inspection resources to MCESD through a CAA section 105 
grant. These resources will be used by the County to verify compliance 
with the FIP rule. In order to remove the FIP requirement, MCESD will 
have to submit to EPA a credible implementation strategy for Rule 310, 
including the provision of the additional inspection and enforcement 
resources needed to ensure implementation of its rule. Individual 
cities can reduce the scope of the FIP once EPA has approved ordinances 
submitted as SIP revisions that eliminate and/or control these sources.
Enforceable Commitment for Agriculture
    As mentioned above, EPA has approved Maricopa County Rule 310 which 
requires control of fugitive dust sources, including agricultural 
sources. However, MCESD is not ensuring adequate enforcement of the 
rule for agricultural fields and aprons. Therefore, EPA has developed 
an enforceable commitment in regulatory form for the FIP that requires 
EPA to propose controls on agricultural sources by September 1999 and 
implement these controls by July 2000. In discussions with key 
stakeholders, general agreement was reached that these controls will be 
in the form of best management practices. EPA believes that this 
approach will ensure successful dust control in Maricopa's unique 
environment. In order to remove the FIP requirements, the State will 
need to submit and received approval of a SIP measure that replaces the 
enforceable commitment. EPA is working closely with the regulatory 
agencies and the agricultural community to accomplish this goal.

[[Page 15922]]

Tribal Issues
    There are three Indian reservations located within the Phoenix 
nonattainment area and which therefore could be considered subject to 
the FIP. However, since this FIP is designed to fill a gap that exists 
in the State plan, and the State plan does not apply to sources within 
Indian country, EPA has decided it is inappropriate to include the 
Indian reservations in this FIP. All three tribes have expressed an 
interest in developing air quality programs. EPA will develop the data, 
in cooperation with the tribes, that is needed to properly assess 
whether controls are required to attain the standards. EPA will ensure 
that controls are implemented either through EPA-approved tribal 
measures or, if necessary, federal measures.

C. Public Involvement in the FIP Process

    Each area has its own unique qualities and concerns. EPA can fully 
understand those concerns, and plans to take them into account, through 
direct participation by the affected community; therefore, in addition 
to the meetings that EPA has already had with the Phoenix community, 
there will be additional opportunities for public input. EPA wants to 
make the final plan a product of local involvement and consensus. EPA 
believes strongly that it can best fulfill the goal of the Clean Air 
Act--that is, clean and healthy air for everyone--and meet the Agency's 
court-ordered obligations by preparing this plan with the input of the 
local community.
    After this proposed action is signed and published in the Federal 
Register, EPA will hold a workshop and public hearing on April 16, 1998 
in the City of Phoenix. The workshop will provide an opportunity for 
EPA to explain to the community why it is imposing this FIP, what 
measures are included in this FIP, and who will potentially be impacted 
by the FIP. The workshop will also provide the community the 
opportunity to ask questions of EPA, and to make suggestions with 
respect to its proposed action. The public hearing will follow the 
workshop. During the public hearing, EPA will be taking formal comment 
on the FIP proposal. The public comment period will begin upon 
publication of the FIP proposal and will remain open for 30 days 
following the public hearing, or until May 18, 1998. EPA encourages 
everyone who has an interest in this proposed action to comment upon 
it. EPA will consider all comments received during the public comment 
period.

II. Background

A. Clean Air Act Requirements

1. Designation and Classification
    On the date of enactment of the 1990 Clean Air Act Amendments, PM-
10 areas, including portions of the pre-existing Maricopa 
County1 PM-10 nonattainment area, meeting the conditions of 
section 107(d) of the Act were designated nonattainment for the PM-10 
national ambient air quality standards (NAAQS)2 by operation 
of law. Once an area is designated nonattainment, section 188 of the 
Clean Air Act (CAA) 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 PM-10 nonattainment areas were 
initially classified as ``moderate'' by operation of law. 56 FR 11101 
(March 15, 1991).
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    \1\``Maricopa,'' ``Maricopa County'' and ``Phoenix'' are used 
interchangeably throughout this proposal to refer to the 
nonattainment area.
    \2\There are two PM-10 NAAQS, a 24-hour standard and an annual 
standard. 40 CFR 50.6. EPA promulgated these NAAQS on July 1, 1987 
(52 FR 24672), replacing standards for total suspended particulate 
with new standards applying only to particulate matter up to 10 
microns in diameter (PM-10). At that time, EPA established two PM-10 
standards. The annual PM-10 standard is attained when the expected 
annual arithmetic average of the 24-hour samples for a period of one 
year does not exceed 50 micrograms per cubic meter (g/
m3). The 24-hour PM-10 standard of 150 g/
m3 is attained if samples taken for 24-hour periods have 
no more than one expected exceedance per year, averaged over 3 
years. See 40 CFR 50.6 and 40 CFR part 50, Appendix K.
    On July 18, 1997, EPA revised both the annual and the 24-hour 
PM-10 standards and also established two new standards for PM, both 
applying only to particulate matter up to 2.5 microns in diameter 
(PM-2.5)(62 FR 38651). While the revised suite of PM standards 
reflects an overall strengthening of the regulatory standard for 
particulate matter, the revised 24-hour PM-10 standard, viewed by 
itself, represents a relaxation of that standard. As such, for areas 
such as Phoenix that had not attained the pre-existing 24-hour 
standard at the time of the relaxation, CAA section 172(e) calls for 
application of controls to be promulgated by EPA that are no less 
stringent than would have been required for areas designated 
nonattainment prior to the relaxation. While today's proposed 
actions relate only to the CAA requirements concerning the 24-hour 
and annual PM-10 standards, as originally promulgated in 1987, the 
proposed FIP is consistent with the section 172(e) requirement.
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    A moderate area could subsequently be reclassified as ``serious'' 
under CAA section 188(b)(1), if, at any time, EPA determined that the 
area could not practicably attain the PM-10 NAAQS by the applicable 
attainment date for moderate areas, December 31, 1994. Moreover, a 
moderate area would be reclassified by operation of law if EPA 
determined after the applicable attainment date that, based on actual 
air quality data, the area was not in attainment after that date. CAA 
section 188(b)(2).
    On May 10, 1996, EPA published a final reclassification of the 
Maricopa County PM-10 nonattainment area as a serious PM-10 
nonattainment area based on actual air quality data. 61 FR 21372. 
Having been reclassified, the area is required to meet the serious area 
requirements in the CAA, including a demonstration that the area will 
attain the PM-10 NAAQS as expeditiously as practicable but no later 
than December 31, 2001. CAA sections 188(c)(2) and 189(b).3 
Pursuant to section 189(b)(2), the State of Arizona was required to 
submit a serious area plan addressing both PM-10 NAAQS for the area by 
December 10, 1997.4
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    \3\While the serious area PM-10 CAA requirements are referenced 
periodically throughout this notice, EPA's FIP obligation, the 
subject of today's proposal, relates only to the moderate area 
statutory requirements.
    \4\By letter dated December 11, 1997 from Russell Rhoades, ADEQ, 
to Felicia Marcus, EPA, Arizona submitted revisions to the Arizona 
SIP for achieving and maintaining the PM-10 NAAQS. These revisions 
consist of particulate control measures in the document ``Serious 
Area Committed Particulate Control Measures for PM-10 for the 
Maricopa County Nonattainment Area and Support Technical Analysis,'' 
Maricopa Association of Governments (MAG), December 1997. On 
February 6, 1998, EPA found that these measures meet the Agency's 
completeness criteria as set forth at 40 CFR part 51, Appendix V, 
but has not yet approved or disapproved them. Also on February 6, 
1998, EPA found, pursuant to CAA section 179(a), that Arizona had 
failed to submit the serious area nonattainment plan for Phoenix by 
the required date. In the same rule, EPA found that Arizona had 
failed to submit certain portions of the moderate area plan for the 
area. 63 FR 9423 (February 25, 1998). These moderate area portions 
are discussed further below.
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2. Moderate Area Planning Requirements
    The air quality planning requirements for PM-10 nonattainment areas 
are set out in subparts 1 and 4 of title I of the Clean Air Act. EPA 
has issued a ``General Preamble''5 describing EPA's 
preliminary views on how the Agency intends to review SIPs and SIP 
revisions submitted under Title I of the Act, including those state 
submittals containing moderate PM-10 nonattainment area SIP provisions.
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    \5\See ``State Implementation Plans; General Preamble for the 
Implementation of Title I of the Clean Air Act Amendments of 1990,'' 
(General Preamble) 57 FR 13498 (April 16, 1992) and 57 FR 18070 
(April 28, 1992).
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    Those states containing initial moderate PM-10 nonattainment areas 
were required to submit, among other things, the following provisions 
by November 15, 1991:
    (a) 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

[[Page 15923]]

adoption, at a minimum, of reasonably available control technology 
(RACT)) shall be implemented no later than December 10, 1993 (CAA 
sections 172(c)(1) and 189(a)(1)(C));
    (b) Provisions to assure implementation of RACT on major stationary 
sources of PM-10 precursors except where EPA has determined that such 
sources do not contribute significantly to exceedances of the PM-10 
standards (CAA section 189(e));
    (c) 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 (CAA section 189(a)(1)(B));
    (d) For plan revisions demonstrating attainment, quantitative 
milestones which are to be achieved every 3 years and which demonstrate 
reasonable further progress (RFP), as defined in section 171(l), toward 
attainment by the applicable attainment date (CAA section 
189(c));6 and
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    \6\As will be seen below, the proposed PM-10 FIP for the 
Maricopa area does not demonstrate attainment by the applicable 
attainment deadline, but rather includes the alternative 
demonstration that attainment by that date is impracticable. 
Therefore, section 189(c) does not apply and is not discussed 
further in this notice.
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    (e) For plan revisions demonstrating impracticability, such annual 
incremental reductions in PM-10 emissions as are required by part D of 
the Act or may reasonably be required by the Administrator for the 
purpose of ensuring attainment of the PM-10 NAAQS by the applicable 
attainment date (CAA sections 172(c)(2) and 171(1)).
    Moderate area plans were also required to 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 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, and EPA guidance implementing 
these provisions.
3. Federal Implementation Plan Provisions
    Section 110(c) of the CAA provides that:

    (1) The Administrator shall promulgate a Federal implementation 
plan at any time within 2 years after the Administrator--
    (A) finds that the State has failed to make a required 
submission or finds that the plan or plan revision submitted by the 
State does not satisfy the minimum criteria established under 
section 110(k)(1)(A),7 or
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    \7\Section 110(k)(1)(A) requires the Administrator to promulgate 
minimum criteria that any plan submission must meet before EPA is 
required to act on the submission. These completeness criteria are 
set forth at 40 CFR part 51, Appendix V.
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    (B) disapproves a State implementation plan submission in whole 
or in part, unless the State corrects the deficiency, and the 
Administrator approves the plan or plan revision, before the 
Administrator promulgates such Federal implementation plan.

    Section 302(y) defines the term ``Federal implementation plan'' in 
pertinent part, as:

    A plan (or portion thereof) promulgated by the Administrator to 
fill all or a portion of a gap or otherwise correct all or a portion 
of an inadequacy in a State implementation plan, and which includes 
enforceable emission limitations or other control measures, means or 
techniques (including economic incentives, such as marketable 
permits or auctions of emissions allowances).

    EPA has wide-ranging authority under section 110(c) to fill in gaps 
left by a State failure. EPA's authority to prescribe FIP measures is 
of three types. First, EPA may promulgate any measure which it has 
authority to issue in a non-FIP context. Second, EPA may invoke section 
110(c)'s general FIP authority and act to cure a planning inadequacy in 
any way not clearly prohibited by statute. Third, under section 110(c) 
the courts have held that EPA may exercise all authority that the State 
may exercise under the Act. For a more detailed discussion of these 
authorities and restrictions on EPA's FIP authorities, see 59 FR 23262, 
23290-23292 (May 5, 1994).
4. Indian Reservations
    a. EPA's FIP Obligation. As stated above, the purpose of EPA's 
proposed FIP is ``to fill all or a portion of a gap or otherwise 
correct all or a portion of an inadequacy in a State implementation 
plan,'' as specified in section 302(y). Because, except in the rare 
special circumstances that have not been shown to apply to Arizona, 
states have no jurisdiction to impose statutory or regulatory 
requirements in Indian country, the gaps in the Arizona PM-10 SIP for 
the Phoenix nonattainment area do not extend to tribal lands. As a 
result, EPA is not required in its proposed FIP to promulgate 
regulations for Indian lands within the Phoenix nonattainment area. 
While EPA is not proposing to extend the provisions of the proposed FIP 
to tribal lands, as discussed below, EPA and tribes, that are 
determined to be eligible by EPA, are authoriized under the CAA to 
protect air quality throughout Indian country.
    b. EPA and Tribal CAA Authority in Indian Country. On February 12, 
1998, EPA issued its final rule pursuant to CAA section 301(d) 
specifying the provisions of the Act for which Indian tribes may be 
treated in the same manner as states; the rule also authorizes eligible 
tribes to implement their own air programs under the Act. 63 FR 7254. 
In the proposed8 and final rule, EPA discusses generally the 
legal basis under the CAA by which EPA and tribes are authorized to 
regulate sources of air pollution in Indian country.
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    \8\See 59 FR 43956 (August 25, 1994).
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    In the rulemaking, EPA concluded that the CAA constitutes a 
statutory grant of jurisdictional authority to Indian tribes that 
allows them to develop air programs for EPA approval in the same manner 
as states. 63 FR at 7254-7259.
    EPA also concluded that the CAA authorizes EPA to protect air 
quality throughout Indian country. See, e.g., CAA sections 101(b)(1), 
301(a), and 502(d), (e), and (i). Therefore, EPA believes that it has 
broad legal authority to provide federal protection in Indian country 
when tribes choose not to develop a program, fail to adopt an adequate 
program or fail to adequately implement a program. In addition, section 
301(d)(4) empowers EPA to directly administer CAA requirements in any 
case where EPA determines that treatment of tribes as identical to 
States is inappropriate or administratively infeasible. 63 FR at 7262. 
See also 59 FR at 43960.
    It is EPA's policy to aid tribes in developing comprehensive and 
effective air quality management programs by providing technical and 
other assistance to them. EPA recognizes, however, that as it required 
many years to develop state and federal programs to cover lands subject 
to state jurisdiction, it will also require time to develop tribal and 
federal programs to cover reservations and other lands subject to 
tribal jurisdiction. 59 FR at 43961.
    EPA promulgated 40 CFR 49.11 in the final Tribal rule, providing 
that the Agency will promulgate a FIP within a reasonable time if 
tribal efforts do not result in EPA-approved programs. 63 FR at 7273. 
EPA has also undertaken an initiative to develop a comprehensive 
strategy for implementing the CAA in Indian country that will 
articulate specific steps the Agency will take to ensure that air 
quality problems in Indian country are addressed either by EPA or the 
tribes themselves. This strategy is currently in draft form. EPA

[[Page 15924]]

also intends to issue national regulations covering various categories 
of air pollution sources that would apply in those situations in which 
a tribe does not have an approved program. 63 FR at 7262-7264.
    In the final Tribal rule, the Agency emphasizes that its strategy 
for implementing the CAA in Indian country is multi-pronged, ``one 
prong of which is federal implementation * * * [t]he other prongs 
derive from a `grass-roots' approach in which staff in the EPA regional 
offices work with individual tribes to assess the air quality problems 
and develop, in consultation with the tribes, either tribal or federal 
strategies for addressing the problems.'' 63 FR at 7264.9
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    \9\EPA then elaborates on this grass-roots approach by 
discussing three components of the Agency's strategy: a needs 
assessment, including the development of emission inventories, 
outreach and communication, and training. 63 FR at 7264.
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    EPA believes that the strategy that it has developed for tribal 
lands in the Phoenix nonattainment area, discussed in section VI below, 
is consistent with the approach outlined above. In short, EPA intends 
to provide technical and financial support to the Tribes in the area so 
that they may develop their own programs if they wish to do so, and to 
develop federal measures should it become necessary.

B. History of Arizona's PM-10 Plans and Related EPA Actions

1. Arizona's Moderate Area PM-10 Plan
    The State of Arizona originally submitted a moderate area PM-10 
plan revision to EPA on November 15, 1991. On March 4, 1992, EPA found 
that the plan did not meet the Agency's completeness criteria at 40 CFR 
part 51, Appendix V, in part because a proper public hearing on the 
plan had not been held. Thereafter the State held another public 
hearing and resubmitted the SIP revision on August 11, 1993. On 
September 7, 1993 EPA found this plan to be complete. The State 
submitted a revised and updated version of the plan on March 3, 1994. 
See generally 59 FR 38402, 38403 (July 28, 1994).
    On April 10, 1995, EPA approved the State's moderate area PM-10 
implementation plan revision for the Maricopa area. 60 FR 18010. Among 
other elements in that plan, EPA approved the State's RFP and RACM 
demonstrations as meeting the requirements of sections 171(1), 
172(c)(1), 172(c)(2), and 189(a)(1)(C) of the CAA. Based on its 
approval of the RACM demonstration, EPA also proposed to approve, as 
meeting the requirements of section 189(a)(1)(B), the State's 
demonstration that even with the implementation of all RACM by December 
10, 1993, it was impracticable for the Maricopa area to attain the PM-
10 NAAQS by December 31, 1994.10
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    \10\The reader should refer to both the proposed approval, 59 FR 
38402, and the final rule, 60 FR 18010, for EPA's interpretation of 
certain moderate area PM-10 requirements of the CAA and the Agency's 
application of these interpretations to the State's moderate area 
PM-10 plan. Those notices should also be consulted for the history 
of the State's PM-10 plan submittals and EPA's actions concerning 
them.
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    On May 1, 1995, the Arizona Center for Law in the Public Interest 
(ACLPI) filed a petition for review of EPA's April 10, 1995 approval of 
the State's moderate area PM-10 plan in the United States Court of 
Appeals for the Ninth Circuit.
    On May 14, 1996, the Ninth Circuit vacated EPA's approval of the 
States's PM-10 moderate area plan. Ober v. EPA, 84 F.3d 304 (9th Cir. 
1996). In short, the Court concluded that the State's moderate area 
plan failed to address the moderate area CAA requirements for 
attainment, RFP and RACM for the 24-hour standard and mandated that EPA 
require the State to do so. The Court also found that EPA had failed to 
provide the required opportunity for comment with respect to the RFP 
and RACM demonstrations for the annual standard. In response to the 
Court's opinion, EPA initiated the following actions.
2. The Microscale Plan--24-hour Standard
    In the wake of the Ninth Circuit's Ober opinion, EPA considered how 
to appropriately implement the Court's directive in the context of the 
State's then-prevailing PM-10 planning efforts for the Maricopa area. 
The Maricopa area was reclassified as a serious PM-10 nonattainment 
area just days before the case was decided and, as noted above, the 
State was required to submit a new PM-10 plan meeting the serious area 
requirements by December 10, 1997.11 Therefore EPA had to 
reconcile the Court's mandate that the State submit a plan correcting 
its moderate area plan deficiencies regarding the 24-hour standard 
concurrent with its responsibility to submit a plan meeting the serious 
area requirements for both NAAQS.
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    \11\For the CAA serious area PM-10 plan requirements, see 
section 189(b). EPA has issued an Addendum to the General Preamble 
(Addendum) describing the Agency's preliminary views on how it 
intends to review SIPs and SIP revisions containing serious area 
plan provisions. See ``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, 42011 (August 16, 1996).
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    EPA concluded that, given the substantial overlap of the moderate 
and serious area planning requirements, it would not be in the public 
interest to require the State to divert its scarce resources into two 
independent planning exercises. At the same time, the Agency recognized 
that timely action (i.e., prior to the serious area plan submittal 
deadline of December 10, 1997) was required in order to be responsive 
to the Court's mandate. Therefore EPA, in consultation with the Arizona 
Department of Environmental Quality (ADEQ) and the 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, in a September 18, 
1996 letter to ADEQ, required submittal of a limited, locally-targeted 
plan (microscale plan) analyzing air quality impacts at specific 
monitoring sites, and meeting both the moderate and serious area 
requirements for the 24-hour standard by May 9, 1997 (extended from an 
original deadline of April 18) 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 State submitted the microscale plan to EPA on May 9, 1997 and 
on August 4, 1997, EPA approved the following portions of the plan:

    (1) under sections 172(c)(1), 189(a)(1)(C) and 189(b)(1)(B), the 
provisions for implementing RACM and best available control 
technology (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 
monitoring sites.
    (3) 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);
    (4) 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
    (5) MCESD's Rule 310 (Open Fugitive Dust Sources), Rule 311 
(Particulate Matter from

[[Page 15925]]

Process Industries) and Rule 316 (Nonmetallic Mineral Mining and 
Processing).

    In the same action, EPA disapproved the following provisions of the 
State's microscale plan:

    (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 monitoring sites.12
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    \12\See EPA's proposed and final actions on the State's 
microscale plan at 62 FR 31025 (June 6, 1997) and 62 FR 41856 
(August 4, 1997).
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3. EPA Actions on Arizona's Moderate Area PM-10 Plan Post-Ober With 
Respect to the Annual Standard
    In response to the Ober decision, EPA provided an opportunity for 
public comment on the State's justifications for rejecting certain 
measures as RACM and on the emission reduction credit granted by the 
Agency for Rule 310 as it related to the State's RFP demonstration. EPA 
also proposed to restore its approval of the RACM, RFP and 
impracticability demonstrations in the State's moderate area plan with 
respect to the annual PM-10 standard. 61 FR 54972 (October 23, 1996).
    As a result of the extensive technical work associated with the 
State's microscale plan, EPA has concluded, as discussed in detail in 
section III below, that it is no longer appropriate to restore its 
approval of the demonstrations in the State's moderate area plan for 
the annual standard. Therefore, EPA is proposing to withdraw its 1996 
proposal and, instead, is now proposing to disapprove the 
impracticability and RACM demonstrations in that plan.

C. History of PM-10 FIP Litigation in Phoenix

    On June 28, 1994, ACLPI filed, on behalf of two Phoenix residents, 
a complaint, No. CIV 94-1318 PHX PGR, in the United States District 
Court for the District of Arizona alleging that EPA was required, 
pursuant to section 110(c) of the CAA, to have promulgated a moderate 
area PM-10 FIP for Phoenix by March 4, 1994, two years after EPA's 
finding that the State's moderate area plan was incomplete. ACLPI 
sought, among other things, an order requiring EPA to promulgate a 
final FIP in 12 months. On February 28, 1995, the district court 
approved a consent decree requiring EPA to take final action on the 
moderate area plan by March 1, 1995. If EPA approved the plan, as 
turned out to be the case, the district court action would be stayed 
pending appellate review.
    On May 1, 1995, ACLPI filed a petition for review of EPA's April 
10, 1995 approval of Arizona's moderate area PM-10 plan for the Phoenix 
area in the United States Court of Appeals for the Ninth Circuit. Ober 
v. EPA, No. 95-70352. On May 14, 1996, the Court issued its opinion in 
the Ober case vacating EPA's approval of the State's plan.13
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    \13\The reader is referred to the text of the opinion for the 
Court's disposition of the range of issues raised by ACLPI in its 
petition. See 84 F.3d 304 (9th Cir. 1996). See also 61 FR 54972 in 
which EPA preliminarily addresses the Court's opinion as it relates 
to the RACM, RFP and attainment demonstrations for the annual 
standard and 62 FR 31025 in which EPA discusses the opinion as it 
relates to the required demonstrations for the 24-hour standard.
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    As a result of the Ninth Circuit's opinion in Ober, the stay of 
proceedings in the district court FIP case was lifted. On November 29, 
1996 and March 25, 1997, respectively, the court approved a second 
consent decree and a modified second consent decree in which EPA agreed 
that if the Agency disapproved the State's microscale plan in whole or 
in part, the Administrator is required to sign by March 20, 1998 a 
Notice of Proposed Rulemaking (NPRM) that sets forth a proposed FIP for 
Phoenix that meets the moderate area PM-10 requirements for the annual 
and 24-hour standards for attainment, RACM and RFP as set forth in CAA 
sections 189(a)(1)(B) and (C), and 172(c)(2) or 189(c)(1). Under the 
decree, EPA must sign a Notice of Final Rulemaking (NFRM) setting forth 
the final FIP by July 18, 1998. EPA's FIP obligation is relieved as to 
any portion of the plan for which EPA signs a NFRM approving corrective 
SIP revisions by July 18, 1998.

III. SIP Actions

A. Proposed Disapproval of Moderate Area Plan

    In its July 28, 1994 proposed approval of the State's moderate area 
plan, EPA noted that the plan's emission inventory identified fugitive 
dust sources as contributing more than 50 percent of the PM-10 
emissions in the Phoenix area. These fugitive dust sources included, 
but were not limited to, construction and demolition activities, 
farming operations, uncovered haul trucks, and emissions from unpaved 
roads. 59 FR 38405. EPA also stated that it believed that Maricopa 
County's fugitive dust rule, Rule 310, fully addressed fugitive dust 
sources in the area. 59 FR 38404. Based in part on this belief and its 
evaluation of the balance of RACM in the plan, EPA proposed and 
eventually found that the moderate area plan assured timely 
implementation of RACM, and that these RACM were sufficient to 
demonstrate RFP but were insufficient to demonstrate attainment by the 
moderate area deadline of December 31, 1994. EPA, therefore, approved 
the RACM, RFP, and impracticability demonstrations in the State's 
moderate area plan. 60 FR 18010.
    As discussed above, EPA's approval of the moderate area plan was 
subsequently vacated in Ober. In October 1996, EPA proposed to restore 
its approval of the RACM, RFP and impracticability demonstrations in 
the State's moderate area plan for the annual standard. 61 FR 54972. 
This proposal was based, in part, on the Agency's continued belief that 
Rule 310 represented RACM for fugitive dust sources in Maricopa County.
    As described previously, EPA subsequently approved in part and 
disapproved in part the State's microscale plan for the 24-hour 
standard. In its evaluation of the microscale plan, EPA found that, in 
fact, Rule 310, due to inadequate commitment of resources by the State, 
does not assure enforcement of RACM on a number of fugitive dust 
sources, including unpaved roads and unpaved parking lots, that are 
legally subject to the rule. In addition, EPA found that there were no 
RACM that applied for agricultural sources. 62 FR 41862.
    While these findings were made in the context of evaluating RACM 
for the 24-hour standard, the findings also apply to the annual 
standard. As noted above, EPA's 1994 approval of the State's moderate 
area plan relied in large part on the Agency's finding that Rule 310 
constituted RACM for fugitive dust sources. As a result of its findings 
with respect to the microscale plan, EPA no longer considers Rule 310 
to satisfy the Act's requirement for enforceable RACM for fugitive dust 
sources not permitted by the County under the rule; therefore, since 
the Agency can no longer find that the State's moderate area plan 
assures the required source compliance with Rule 310 and, hence, does 
not ensure enforcement of RACM as required by the Act, EPA, is 
proposing to disapprove the RACM demonstration for the annual standard 
in the State's moderate area plan.
    In order for a moderate area plan to demonstrate that attainment is 
impracticable, it must make that showing in light of implementation of 
all RACM. 57 FR 13544. Since EPA is now proposing to disapprove the 
RACM

[[Page 15926]]

demonstration in the State's moderate area plan, the Agency is also 
proposing to disapprove the demonstration contained in that plan that 
attainment by the moderate area deadline of December 31, 1994 was 
impracticable.14
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    \14\The discussion in section IV.A. regarding EPA's views of the 
status of the CAA's moderate area attainment requirements following 
an area's reclassification to serious is applicable here and the 
reader is referred to that section.
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    EPA, however, is not proposing to disapprove the RFP demonstration 
in the State's moderate area plan. The estimated emission reductions 
from the implementation of Rule 310 on unpermitted sources accounted 
for less than 20 percent of the total emission reductions from the 
plan. Even without the reductions from the unpermitted sources, EPA 
believes that plan still contains sufficient emission reductions from 
other measures to demonstrate RFP for the annual standard and, 
therefore, disapproval is not warranted. This issue, however, is 
academic since, as noted before, EPA is withdrawing its proposal to 
restore approval of the RFP demonstration for the annual standard in 
the State's plan and is substituting its own proposed RFP demonstration 
for that standard.

B. Withdrawal of Proposal to Restore Moderate Area Plan Demonstrations 
for the Annual PM-10 Standard

    As a consequence of the proposed disapprovals discussed above, EPA 
is today withdrawing its October 26, 1996 proposal (61 FR 54972) to 
restore the Agency's approval of the RACM and impracticability 
demonstrations for the annual standard in the State's moderate area 
plan.
    EPA is today also withdrawing its proposal to restore approval of 
the RFP demonstration for the annual standard in the State's plan. 
While EPA continues to believe that the plan as a whole continues to 
demonstrate RFP, its previous analysis of the State's RFP demonstration 
is no longer valid because it relied in part upon emission reductions 
from the implementation of Rule 310 on a number of unpermitted source 
categories. Under its CAA section 110(c) authority, EPA is proposing 
its own RFP demonstration for the annual standard as described in 
section V.C.

IV. Moderate Area PM-10 Planning Requirements for the FIP Proposal

A. Attainment/Impracticability Demonstration

    Because the moderate area attainment deadline, December 31, 1994, 
has passed, EPA is confronted with the issue of how to define the 
moderate area requirements applicable to the Agency's proposed FIP. EPA 
believes that because the Maricopa area was reclassified from a 
moderate to a serious nonattainment area, the moderate area 
requirements (demonstration of impracticability or attainment by no 
later than December 31, 1994) have been superseded by the serious area 
attainment requirement (attainment by no later than December 31, 2001) 
and are therefore now moot. Having reviewed the CAA's moderate and 
serious area PM-10 attainment provisions, EPA has concluded that when a 
moderate PM-10 area has been reclassified after the moderate area 
attainment deadline has passed and been replaced with a new deadline, 
the moderate area deadline no longer has any logical, practical or 
legal significance.
    Thus, under this interpretation, there would be no need for the 
proposed FIP, to the extent that it is intended to meet the CAA's 
moderate area requirements, to demonstrate attainment. In other words, 
such an attainment demonstration would only be required when the State 
submits its complete serious area plan to comply with the section 
189(b)(1) attainment demonstration requirement. EPA believes that its 
interpretation can be reconciled with the Ober Court's directive that 
EPA require the State to address the moderate area attainment 
requirements for the 24-hour standard and that such an interpretation 
is reasonable given the legal and factual context in which that case 
was decided. EPA's reasoning is explained in detail at 61 FR 54972, 
54974-54975 (October 23, 1996). Nevertheless, EPA complied with the 
Court's remedies regarding the moderate area attainment requirements by 
directing the State to meet those requirements in the microscale 
plan.15 Having complied with the Court opinion by directing 
that the State meet the moderate area attainment requirements in its 
planning efforts, EPA discerns no basis for applying different 
requirements to the Agency in promulgating a moderate area FIP that is 
intended to correct State planning deficiencies.
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    \15\While EPA could have sought clarification on this issue from 
the Ninth Circuit, the Agency did not do so because such a review 
would necessarily have occurred without benefit of a thorough 
briefing on the issue and in the absence of an administrative 
record. The Agency does, however, reserve its right to assert its 
interpretation in any challenge to EPA's implementation of the 
Court's remedies or in the context of other reclassifications.
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    Having determined that the proposed FIP must meet the CAA's 
moderate area attainment requirements, EPA has concluded that since the 
December 31, 1994 deadline has passed and the Maricopa area has been 
reclassified, the only attainment deadline currently applicable to the 
area is the serious area deadline, that is, achievement of attainment 
as expeditiously as practicable, but no later than December 31, 2001. 
Thus, consistent with the terms of section 189(a)(1)(B), the moderate 
FIP must either demonstrate attainment of the PM-10 NAAQS as 
expeditiously as practicable but no later than December 31, 2001, or, 
alternatively demonstrate that attainment by that date is 
impracticable.

B. RACM/RACT Demonstration

    Sections 172(c)(1) and 189(a)(1)(C) read together require that 
moderate area PM-10 plans include RACM and RACT for existing sources of 
PM-10. These plans were to provide for implementation of RACM/RACT no 
later than December 10, 1993. Since the moderate area deadline for the 
implementation of RACM/RACT has passed, EPA has concluded that the 
RACM/RACT required in the FIP must be implemented ``as soon as 
possible.'' Delaney v. EPA, 898 F.2d 687, 691 (9th Cir. 1990). EPA has 
interpreted this requirement to be ``as soon as practicable.'' See 55 
FR 41204, 41210 (October 1, 1990).
    The methodology for determining RACM/RACT is described in detail in 
the General Preamble. 57 FR 13498, 13540-13541. In summary, EPA 
suggests starting to define RACM with the list of available control 
measures for fugitive dust, residential wood combustion, and prescribed 
burning contained in Appendices C1, C2, and C3 of the General Preamble 
and adding to this list any additional control measures proposed and 
documented in public comments. Any measures that apply to emission 
sources of PM-10 and that are de minimis and any measures that are 
unreasonable for technology reasons or because of the cost of the 
control in the area can then be culled from the list. In addition, 
potential RACM may be culled from the list if a measure cannot be 
implemented on a schedule that would advance the date for attainment in 
the area. 57 13498, 13560.
    In addressing cost issues, the General Preamble suggests that in 
case of public sector sources and control measures, the cost evaluation 
should consider the impact of the reasonableness of the measures on the 
governmental entity that must bear the responsibility for their 
implementation. 57 FR 13541.
    The General Preamble does not define ``de minimis'' except to say 
that it would be unreasonable to apply

[[Page 15927]]

controls to sources that are negligible contributors to ambient 
concentrations. 57 FR 13540, footnote 18. The regulatory scheme for PM 
in subpart 4 of the CAA establishes two graduated levels of controls, 
RACM and BACM, depending on the severity of the area's air quality. See 
CAA section 189(a) and (b). These statutory requirements, applicable to 
moderate and serious areas, respectively, clearly contemplate that 
smaller PM sources need not, in the first instance, bear the burden of 
emission reductions. Thus, in determining the initial level of control, 
it is appropriate to focus on what is reasonable and practicable for 
significant sources of PM emissions.
    For its proposed FIP, EPA is proposing to rely on the criteria 
applied to define significant contributors under its new source 
permitting programs (40 CFR 51.165(b)) as a surrogate for determining 
which source categories require the application of RACM. Under EPA's 
new source permitting programs, a PM-10 source is considered to be a 
``significant contributor'' if it contributes 5 g/m\3\ or more 
of PM-10 to a location of expected 24-hour exceedances and 1 
g/m\3\ or more to a location of expected annual violation. 
Therefore, a de minimis source category for the purposes of defining 
which source categories require the application of RACM under section 
189(a)(1)(C), is proposed to be one that contributes less than 5 
g/m\3\ of PM-10 to a location of expected 24-hour exceedances 
and less than 1 g/m\3\ to a location of expected annual 
violations.
    It should be emphasized that the de minimis criterion is invoked 
solely for the purposes of determining which source categories need 
RACM and not for determining which source categories need controls for 
attainment. In establishing this RACM de minimis criterion, EPA is not 
taking the position that de minimis RACM source categories can escape 
controls if such controls are needed for attainment or RFP. In that 
case, it is the Agency's position that the level of control on such 
insignificant sources need only be at the level required to demonstrate 
reasonable further progress and expeditious attainment and that this 
level need not be justified under section 189(a)(1)(C) as RACM.
    For any RACM that EPA rejects for reasons of technology, cost, size 
of source category or timing of implementation as described above, the 
Agency must provide a reasoned justification for the rejection. Once 
the final list of RACM is defined, each RACM must be converted into a 
legally enforceable vehicle such as a rule, permit, or other 
enforceable document. 57 FR 13498, 13541.

C. Reasonable Further Progress (RFP) Demonstration to Follow

    EPA has concluded that for PM-10 plans that demonstrate that it is 
impracticable for an area to attain the NAAQS by the applicable 
attainment date, the governing statutory requirement for RFP is section 
172(c)(2) as defined by section 171(l).16 Section 172(c)(2) 
of the Act states that nonattainment plans shall require reasonable 
further progress (RFP). RFP is defined in section 171(1) as ``such 
annual incremental reductions in emissions of the relevant air 
pollutant as are required by this part [D] or may reasonably be 
required by [EPA] for the purpose of ensuring attainment of the 
applicable [NAAQS] by the applicable date.''
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    \16\EPA originally set forth preliminary guidance on the RFP 
requirements for such plans in its final rule approving the Arizona 
moderate area PM-10 plan for the Phoenix area. See 60 FR 18010, 
18013. The Agency subsequently clarified portions of that guidance 
in its proposal to restore the annual standard demonstrations in the 
State's moderate area plan following the Ninth Circuit's Ober 
decision. See 61 FR 54972, 54973-54974. The reader is referred to 
these notices for an expanded discussion of the Agency's 
interpretation of the RFP requirements for moderate PM-10 areas 
demonstrating impracticability.
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    EPA has interpreted the RFP requirement for areas demonstrating 
impracticability as being met by a showing that the implementation of 
all RACM has resulted in incremental emission reductions below pre-
implementation levels. EPA believes that this interpretation is 
consistent with the definition in section 171(l) and with the statutory 
term ``reasonable further progress.''

V. Summary of EPA's FIP Proposal

    As a moderate area plan, EPA's proposed FIP must demonstrate 
attainment of both the annual and 24-hour PM-10 standards by December 
31, 2001 (as a result of the passing of the moderate area deadline and 
the reclassification to serious) and provide for expeditious 
implementation of RACM for all significant source categories, or 
demonstrate that even with RACM it is impracticable for the area to 
attain by that date. The proposed FIP must also demonstrate RFP 
consistent with the attainment or impracticability 
demonstration.17
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    \17\See section IV. above.
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    EPA's FIP obligation arises only as to SIP provisions that are not 
approved. As discussed previously in section II.B.2., EPA has already 
approved RACM, attainment, and RFP demonstrations for certain sources 
of source categories in the Phoenix area. Specifically, EPA has already 
approved RACM for disturbed cleared areas (e.g., construction sources), 
earth moving, industrial haul roads, and stationary sources and the 
attainment and RFP demonstrations for the 24-hour standard at the 
Maryvale and Salt River monitoring sites. 62 FR 41856. As a result, 
this proposed FIP does not address these SIP elements.
    EPA, however, has disapproved the State's RACM demonstrations for 
the significant source categories of unpaved roads, unpaved parking 
lots, vacant lots, and agricultural fields and aprons as well as its 
attainment and RFP demonstrations for the 24-hour standard at the 
Gilbert and West Chandler monitoring sites. 62 FR 41856. In addition, 
EPA is proposing to disapprove the RACM and attainment/impracticability 
demonstrations for the annual standard in the State's moderate area 
plan and to revise the State's RFP demonstration for this 
standard.18 See Section III.A.
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    \18\ EPA's FIP obligation was initially triggered by an 
incompleteness finding on the State's moderate area plan submittal. 
Although EPA subsequently determined the submittal to be complete, 
the FIP obligation continues until there is a fully approved SIP in 
place.
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    The following sections describe EPA's proposals to address each of 
the outstanding elements of the Phoenix moderate plan: RACM/RACT 
demonstration, attainment/impracticability demonstrations, and RFP 
demonstrations.

A. RACM/RACT Demonstration

1. RACT and PM-10 Precursors
    a. RACT. In the General Preamble, EPA recommends that major 
stationary sources of PM-10 be the starting point for a reasonably 
available control technology (RACT) analysis. 57 FR 13541. Stationary 
sources of PM-10 in the Phoenix area include power plants, concrete 
manufacturing, sand and gravel operations, and cotton ginning. MCESD 
has adopted regulations requiring RACT for stationary sources of PM-10: 
Rule 311, ``Particulate Matter from Process Industries,'' and Rule 316, 
``Nonmetallic Mineral Mining and Processing.'' These measures were 
approved by EPA in 1995 as RACT for PM-10 stationary sources as part of 
the moderate area plan approval. 60 FR 18009. While not at issue in the 
litigation regarding that plan's approval, EPA's approval of these 
rules was also incidentally vacated by the Ober decision. The Agency 
restored these RACT rules to the SIP as part of its action on the 
microscale plan. 62 FR 41862.

[[Page 15928]]

    b. PM-10 Precursors. Under CAA section 189(e), the control 
requirements applicable to major stationary sources of PM-10 must also 
be applied to major stationary sources of PM-10 precursors, unless EPA 
determines such sources do not contribute significantly to PM-10 levels 
in excess of the NAAQS in the area. ``Significantly'' is not defined in 
either the Act or in the General Preamble. Rather, for moderate areas, 
the determination is to be made on a case-by-case basis. 57 FR at 
13539. For this action, EPA proposes to rely on the criteria applied 
under its new source permitting programs (40 CFR 51.165(b)) to guide 
its review of whether major stationary sources of PM-10 precursors 
significantly contribute to PM-10 levels in excess of the standard. See 
Section IV.B. A major stationary source in a moderate area is one that 
emits or has the potential to emit 100 tons per year or more of PM-10 
or a PM-10 precursor. 57 FR 13538.
    PM-10 precursors can include sulfur oxides (SOX), 
nitrogen oxides (NOX), ammonia, and volatile organic 
compounds (VOCs). In the Phoenix area, VOCs are not important in 
secondary particulate formation. Sulfur oxide emissions in the area are 
dominated by emissions from non-road engines and thus major sources of 
SOX account for less than 10 percent of the total inventory. 
Nitrogen oxide emissions are almost entirely (90 percent) from on- and 
non-road engines, with major stationary sources accounting for only 4.3 
percent of the total inventory. Livestock operations (which are not 
considered major point sources) account for 99.8 percent of ammonia 
emissions. See Tables 2-2 and B3-1 in ``1994 Regional PM-10 Emission 
Inventory for the Maricopa County Nonattainment Area,'' Draft Final 
Report, MAG, May 1997. In total, major point sources account for less 
than 7 percent of the total precursor inventory.
    Draft PM-10 air quality modeling for the Phoenix nonattainment area 
indicates that exceedances of both the 24-hour and annual standards are 
attributable chiefly to direct particulate matter emissions from re-
entrained dust from paved roads and fugitive dust from disturbed 
surfaces such as construction sites and agricultural fields. The draft 
modeling also indicates that secondary particulate formation from all 
sources of precursors (including natural background) contributes from 
3.6 to 9.4 g/m\3\ to the modeled 24-hour episodes. See 
``Technical Support Document for the Regional PM-10 Modeling in Support 
of the 1997 Serious Area PM-10 Plan for Maricopa County Nonattainment 
Area,'' Draft Report, MAG, October 1997, Table 3-26 (MAG Modeling TSD). 
No contribution from secondary particulates to the annual standard was 
estimated in the draft modeling; however, based on a crude average of 
the results of the eight 24-hour episodes modeled, the annual total 
impact (including background) of secondary particulates is around 5.6 
g/m\3\.
    From these modeling results, and assuming that a source's 
contribution to secondary particulate levels is proportional to its 
presence in the inventory, major stationary sources of PM-10 precursors 
contribute no more than 0.6 g/m\3\ to the 24-hour standard and 
0.3 g/m\3\ to the annual standard (the actual contribution is 
likely to be less when the background levels of secondary particulates 
are factored out). Both these levels are well below the 5 g/
m\3\ 24-hour standard and 1 g/m\3\ annual standard 
significance levels; therefore, EPA proposes to find, based on existing 
modeling, that major stationary sources of PM-10 precursors do not 
contribute significantly to PM-10 levels in the Maricopa area which 
exceed the PM-10 NAAQS, and therefore, RACT on these major sources is 
not required under section 189(e). With this proposal, which is based 
on an assessment of the current mix of sources and meteorological 
patterns, EPA is not drawing any conclusions on the potential future 
need or desirability of controls on major sources of PM-10 precursors 
to assure eventual attainment of the PM-10 standard in the Phoenix 
area.
2. RACM Approach
    As discussed in section IV.B. above, EPA's General Preamble 
suggests determining RACM by beginning with the list of measures found 
in Appendix C to the General Preamble and adding to that list any 
measures which have been suggested by public comments. Any measures 
that are determined to apply to emission sources of PM-10 that are de 
minimis and any measures that are technologically infeasible or have 
unreasonable costs can then be culled from the list. A reasoned 
justification must be provided for each measure that is rejected as 
RACM. 57 FR 13498, 13540.
    EPA has identified a list of 99 potential control measures. This 
list of measures is taken from the list of measures developed for the 
State's 1991 moderate area plan and includes the measures found in 
Appendix C to the General Preamble as well as measures recommended by 
the Maricopa air agencies and in public comments on the moderate area 
plan.19 The measures range from fugitive dust and 
transportation control measures to measures which achieve reductions 
from national transportation sources such as aircraft and trains.
---------------------------------------------------------------------------

    \19\The 1991 MAG plan identified 79 potential RACM with an 
additional 82 potential measures identified from public comment. 
Many of these public comment measures, however, duplicated measures 
on the original list of 79.
---------------------------------------------------------------------------

    Before evaluating measures as RACM, EPA first screened the list of 
99 measures to determine which measures were applicable to the Phoenix 
area and for which EPA had legal authority. EPA then screened the list 
to determine which measures it has already approved as State RACM or 
adopted at the federal level and considers RACM. Where EPA has already 
determined a measure to be RACM, no further analysis of the measure is 
necessary. Finally, the Agency evaluated the resulting shorter list of 
measures based on the General Preamble's RACM criteria to identify 
which measures constituted RACM for the Phoenix area.
    Readers should note that the following analysis is meant to apply 
only in the limited instance of this moderate area PM-10 FIP for the 
Maricopa County area and only to the determination of the availability 
and reasonableness of controls for adoption and implementation by EPA 
and not by the State of Arizona, its local jurisdictions or other 
states. In contrast to EPA's regulatory authority as a federal 
executive-branch agency, the concept of ``state'' as used in the Clean 
Air Act embodies both the state's executive and more extensive 
legislative functions and therefore includes the authority not only to 
regulate but also to establish new legal authority and to raise funds 
for necessary programs. As a result, it is likely that the State could 
adopt and implement a broader range of RACM.
    Because there are both a 24-hour and an annual PM-10 standard, EPA 
must evaluate whether each measure is reasonably available for each 
standard. However, except for the de minimis criterion discussed later, 
the criteria EPA used to determine potential RACM are equally 
applicable to both PM-10 standards, that is, each criterion and the 
results of applying the criterion to a measure do not vary depending on 
whether the measure is being evaluated for the 24-hour or annual 
standard. As a result, a completely separate RACM analysis for each 
standard is not warranted and has not been performed.

[[Page 15929]]

3. Federal Implementation Criteria
    a. Applicability to the Phoenix Area. Before a measure can be 
considered as potential RACM, EPA must first determine if the measure 
would have any inherent potential to reduce PM-10 emissions in the 
Phoenix area. Some of the listed measures cover sources that are not 
represented in the Phoenix area, such as marine vessel 
operations20 and deicing materials, and were rejected from 
further evaluation on this basis.
---------------------------------------------------------------------------

    \20\Marine vessel operations here mean commercial port traffic 
operations and not pleasure or recreational boating operations. 
Emissions from pleasure/recreational boat engines are covered under 
non-road engine standards.
---------------------------------------------------------------------------

    In addition, many of the 99 measures were taken from the ozone or 
CO air quality plans for the Phoenix area and are primarily intended to 
reduce CO or ozone precursor emissions. Several of these measures do 
not reduce PM-10 emissions. For example, since PM-10 emissions from 
both tailpipes and re-entrained dust from paved roads are independent 
of the speed of vehicles, measures that simply improve traffic flow and 
thus improve overall traffic speeds have no effect on primarily-emitted 
PM-10.21
---------------------------------------------------------------------------

    \21\Nor do such flow improvements have a beneficial effect on 
secondary particulate levels since emissions of the major PM-10 
precursor from on-road motor vehicles, NOx, increase with speed.
---------------------------------------------------------------------------

    Note that this criterion is not addressing whether the measure 
could be implemented in the Phoenix area in a manner that would achieve 
PM-10 emission reductions. Implementation feasibility will be 
considered as part of the technical feasibility criterion below.
    b. Existing RACM. In some instances, EPA has already SIP-approved a 
measure or very similar measure as RACM or has promulgated at the 
federal level a measure that it considers to be RACM. Where EPA has 
already determined a measure to be RACM, no further analysis of the 
measure is necessary.
    c. Legal Authority. EPA must have the legal authority under the 
Clean Air Act to promulgate, implement and enforce a measure, and must 
not be preempted from promulgating, implementing, or enforcing it by 
other federal statutes, regulations or court orders before it considers 
a measure reasonably available. EPA's FIP authority under CAA section 
110(c) is broad (see section II.A.3. above); however, the Agency is 
constrained in specific instances by the Act itself. See e.g., CAA 
section 110(a)(5)(A)(i) (prohibition on indirect source review 
programs) and section 110(c)(2)(B) (prohibition on parking surcharges).
    Additionally, EPA's authority to promulgate measures in a FIP which 
would require the State to enact legislation or expend state funds is 
limited. EPA may require the State to enact legislation or expend its 
funds if the FIP measures affect the pollution-creating activities of 
the State, but may not do so if the effect is to govern the pollution-
creating activities of others. For example, EPA could not require a 
state to expand a mass transit system in order to reduce emissions from 
private automobiles. EPA could, however, require a state to retrofit 
state-owned buses to reduce emissions from those buses. For a detailed 
discussion of this issue, see 52 FR 23263, 23291-23292 (February 5, 
1994) (proposed ozone and CO FIP for the South Coast Air Basin).
4. Application of Federal Implementation Criteria
    Table 1 provides an overview of the application of the above 
federal implementation criteria to the 99 measures. Table 1 also 
identifies which measures EPA has already approved as RACM or has 
already promulgated a federal measure that it considers RACM (e.g., 
diesel fuel standards). Of the 99 measures, 21 were eliminated because 
the sources do not exist in the Phoenix area or the measure does not 
beneficially affect PM-10 emissions, 11 because EPA had already 
approved or promulgated RACM, and 11 measures because EPA does not have 
the legal authority to adopt and/or implement the measure. 
Consequently, 56 measures were considered for inclusion in the proposed 
FIP. A more detailed discussion of EPA's reasons for rejecting a 
measure can be found in the Technical Support Document for today's 
proposed action.
    In order to evaluate its ability to implement each of these 
measures, EPA had to first identify how it would implement the measure. 
EPA considered three basic methods of implementation: (1) by rule 
requiring the owner/operator of the source to implement the control, 
(2) by direct action (e.g., EPA would pave a road), or (3) by providing 
additional funding to the State or local agency to implement the 
measure (e.g., expand MAG ridesharing). The implementation method(s) 
assumed for a measure is indicated in Table 1 by the number in 
parentheses after the description of the measure. These numbers 
correspond to the numbers above.

    Note: Where a measure is not applicable to the Phoenix area or 
where the Agency lacks legal authority, EPA has not analyzed the 
measure for the remaining criteria. This is indicated by dashes in a 
column. A question mark in a legal authority column indicates that 
EPA's legal authority is uncertain at this time; however, for the 
purposes of this analysis, question marks are treated as yeses.

                            Table 1.--Measures Appropriate for Federal Implementation                           
----------------------------------------------------------------------------------------------------------------
                                                                                                      Available 
              Source category and measure                 Appropriate   No approved      Legal         federal  
                                                         to PHX PM-10      RACM      authorization    measures  
----------------------------------------------------------------------------------------------------------------
                                A.1. Paved Road Dust--Reduce Dust (Silt) Loading                                
----------------------------------------------------------------------------------------------------------------
1. Pave, vegetate, or chemically stabilize access                                                               
 points where unpaved traffic surfaces adjoin paved                                                             
 roads (1).............................................            Y             Y              Y             Y 
2. Require haul trucks to be covered (1)...............            Y             Y              Y             Y 
3. Provide for traffic rerouting/rapid clean-up of                                                              
 temporary sources of dust (water erosion, track out,                                                           
 material spills) (1)..................................            Y           Y/N              Y             Y 
4. Improved material specification for deicing                                                                  
 materials (1).........................................            N   ............  .............            N 
5 Require curbing and pave or stabilize road shoulders                                                          
 (1)...................................................            Y             Y              ?             Y 
6. Provide for stormwater drainage to prevent water                                                             
 erosion onto paved roads (2/3)........................            Y             Y              ?             Y 
7. Mitigation of freeway construction impacts (1)......            Y           Y/N              Y             Y 
----------------------------------------------------------------------------------------------------------------
                              A.2. Paved Road Dust/Tailpipe Emissions--Reduce VMT                               
----------------------------------------------------------------------------------------------------------------
1. Implement short range transit improvements (2/3)....            Y             Y              ?             Y 
2. Implement long range transit improvements (2/3).....            Y             Y              ?             Y 

[[Page 15930]]

                                                                                                                
3. Require exclusive bus lanes on arterials and                                                                 
 freeways (2/3)........................................            Y             Y              ?             Y 
4. Expand MAG rideshare program (2/3)..................            Y             Y              Y             Y 
5. Adopt trip reduction ordinance......................            Y             Y              Y             Y 
6. Establish voluntary no drive days (2/3).............            Y             Y              Y             Y 
7. Establish an areawide public awareness program (2/3)            Y             Y              Y             Y 
8. Build/establish park and ride lots (2/3)............            Y             Y              Y             Y 
9. Provide employees financial incentives (e.g., zero                                                           
 bus fares) in lieu of parking (1).....................            Y             Y              Y             Y 
10. Require employers to provide preferential parking                                                           
 for car and van pools (1).............................            Y             Y              Y             Y 
11. Require mandatory parking charges for employees (1)  ............  ............             N             N 
12. Build HOV lanes on freeways (3)....................            Y             Y              ?             Y 
13. Build HOV lanes on arterials (3)...................            Y             Y              ?             Y 
14. Build HOV ramps which bypass metering signals (3)..            Y             Y              ?             Y 
15. Promote increased bicycle use (3)..................            Y             Y              Y             Y 
16. Provide or require bicycle travel (e.g., lanes) and                                                         
 support facilities (e.g., lockers and racks) (3)......            Y             Y              ?             Y 
17. Promote pedestrian travel through provisions of                                                             
 pedestrian facilities (e.g. sidewalks) (3)............            Y             Y              ?             Y 
18. Provide pedestrian overpasses (3)..................            Y             Y              ?             Y 
19. Promote the use of/require employers to provide                                                             
 alternative work hours (1)............................            Y             Y              Y             Y 
20. Promote the use of/require employers to provide                                                             
 alternative work weeks (1)............................            Y             Y              Y             Y 
21. Promote the use of telecommuting (1)...............            Y             Y              Y             Y 
22. Promote the use of teleconferencing (1/2/3)........            Y             Y              Y             Y 
23. Provide auto free zones and pedestrian malls (2/3).            Y             Y              N             N 
24. Provide vanpool purchase incentives such as tax                                                             
 breaks (1)............................................            Y             Y              N             N 
25. Require merchants to provide alternative                                                                    
 transportation incentives to customers (1)............            Y             Y              Y             Y 
26. Implement congestion pricing (2/3).................            Y             Y              N             N 
27. Require non-employee parking to be priced (1)......            Y             Y              N             N 
28. Impose fee on vehicles related to emissions (smog                                                           
 fees) (1).............................................            Y             Y              Y             Y 
29. Encourage private sector transit by state                                                                   
 deregulation (1)......................................            N   ............  .............            N 
30. Evaluate & mitigate air quality impacts from new                                                            
 development (indirect source review) (1)..............            Y             Y              N             N 
31. Require increased land use density along transit                                                            
 routes (1)............................................            Y             Y              N             N 
32. Provide a fee-based tradable travel permit program                                                          
 (1/2).................................................            Y             Y              N             N 
33. Set up system of road pricing (2/3)................            Y             Y              N             N 
----------------------------------------------------------------------------------------------------------------
                       B. On-Road Vehicle Exhaust--Tailpipe and Non-VMT Reduction Measures                      
----------------------------------------------------------------------------------------------------------------
1. Expand current I/M to all model years (1/2/3).......            Y             Y              Y             Y 
2. Expand the current I/M program statewide (1/2/3)....            Y             Y              Y             Y 
3. Expand the current I/M program countywide (1/2/3)...            Y             Y              Y             Y 
4. Require the use of No. 1 diesel fuel (1)............            Y             N              Y             N 
5. Require clean fuels for fleet vehicles (1)..........            Y             Y              Y             Y 
6. CA new car standards (1)............................            Y             Y              Y             Y 
7. Reduce cold start emissions (1).....................            N   ............  .............            N 
8. Scrap higher polluting vehicles (2/3)...............            Y             Y              Y             Y 
9. Reduce idling at drive up facilities (1)............            N   ............  .............            N 
10. More strictly enforce traffic, parking, air                                                                 
 pollution regulations (2)\1\..........................            Y             Y              N             N 
11. Freeway surveillance (2/3).........................            N   ............  .............            N 
12. Ramp metering & signage (2/3)......................            N   ............  .............            N 
13. Traffic signal synchronization (1/2/3).............            N   ............  .............            N 
14. Reversible lanes on arterials (1/2/3)..............            N   ............  .............            N 
15. One way streets (1/2/3)............................            N   ............  .............            N 
16. Truck restrictions during peak periods (1/2/3).....            N   ............  .............            N 
17. Intersection improvements (2/3)....................            N   ............  .............            N 
18. On street parking restrictions (1/2/3).............            N   ............  .............            N 
19. Bus pullouts in curbs (1/2/3)......................            N   ............  .............            N 
20. Alternative fuels for buses/electric shuttle buses                                                          
 (1)...................................................            Y             Y              Y             Y 
21. Emission controls on public diesel vehicles (1)....            Y             N   .............            N 
----------------------------------------------------------------------------------------------------------------
                           C. Dust from Unpaved Road/Parking Lot/Disturbed Vacant Lots                          
----------------------------------------------------------------------------------------------------------------
1. Pave or otherwise stabilize permanent unpaved haul                                                           
 roads, and parking or staging areas at commercial,                                                             
 municipal, or industrial facilities (1)...............            Y             N   .............            N 
2. Require sources to submit dust control plans (1)....            Y        \2\N/Y              Y             Y 
3. Develop traffic reduction plans on unpaved roads (1)            Y             Y              Y             Y 
4. Limit use of recreational vehicles on open land (1).            Y             Y              Y             Y 
5. Pave or stabilize unpaved roads (1).................            Y             Y              Y             Y 
6. Pave or stabilize unpaved parking areas (1).........            Y             Y              Y             Y 
7. Require controls on material storage piles (1)......            Y             N   .............            N 

[[Page 15931]]

                                                                                                                
8. Require stabilization of wind erodible soils (1)....            Y             Y              Y             Y 
9. Require windbreaks, watering, paving, vegetating for                                                         
 windblown dust (1)....................................            Y             Y              Y             Y 
10. Restrict blowers for landscaping (1)...............            Y             Y              Y             Y 
----------------------------------------------------------------------------------------------------------------
                                             D. Agricultural Sources                                            
----------------------------------------------------------------------------------------------------------------
1. Rely on soil conservation requirements (e.g.,                                                                
 conservation plans) of the Food Security Act (1)......            Y             Y              Y             Y 
2. Require windbreaks for agricultural sources (1).....            Y             Y              Y             Y 
----------------------------------------------------------------------------------------------------------------
                                      E. Residential Wood Combustion (RWC)                                      
----------------------------------------------------------------------------------------------------------------
1. Establish an episodic curtailment program for RWC (1/                                                        
 2/3)..................................................            Y             N   .............            N 
2. Establish a public education/information program for                                                         
 RWC (2/3).............................................            Y             N   .............            N 
3. Encourage the improved performance of RWC devices                                                            
 (1)...................................................            Y             N   .............            N 
4. Provide inducements to reduce number of RWC devices                                                          
 (1/2/3)...............................................            Y             N   .............            N 
----------------------------------------------------------------------------------------------------------------
                                              F. Other Area Sources                                             
----------------------------------------------------------------------------------------------------------------
1. Develop a smoke management program for prescribed                                                            
 burns (1).............................................            Y             N   .............            N 
----------------------------------------------------------------------------------------------------------------
                                                G. Point Sources                                                
----------------------------------------------------------------------------------------------------------------
1. RACT for stationary sources (1).....................            Y             N   .............            N 
----------------------------------------------------------------------------------------------------------------
                                             H. Marine Vessel/Ports                                             
----------------------------------------------------------------------------------------------------------------
1. Divert port related truck traffic to rail (1).......            N   ............  .............            N 
2. Control emissions from ship berthing facilities (1).            N   ............  .............            N 
3. Control fugitive emissions from marine vessels (1)..            N   ............  .............            N 
4. Control emissions from marine diesel operations (1).            N   ............  .............            N 
5. Limit the sulfur content of marine fuel (1).........            N   ............  .............            N 
----------------------------------------------------------------------------------------------------------------
                                                 I. Locomotives                                                 
----------------------------------------------------------------------------------------------------------------
1. Reduce rail crossings (1)...........................            Y             Y              N             N 
2. Control switching locomotives (1)...................            Y             Y              Y             Y 
3. Electrify rail lines (1)............................            Y             Y              Y             Y 
----------------------------------------------------------------------------------------------------------------
                                      J. Airplanes/Airport Ground Equipment                                     
----------------------------------------------------------------------------------------------------------------
1. Centralized airport ground power systems (1)........            Y             Y              Y             Y 
2. Reduce emissions from airport ground access vehicles                                                         
 (1)...................................................            Y             Y              Y             Y 
3. Establish tighter emissions standards for new jet                                                            
 engines (1)...........................................            Y             Y              Y             Y 
4. Control emissions from aircraft and ground service                                                           
 vehicles (1)..........................................            Y             Y              Y             Y 
5. Require replacement of high emitting aircraft (1)...            Y             Y              Y             Y 
6. Require general aviation vapor recovery (1).........            N   ............  .............            N 
----------------------------------------------------------------------------------------------------------------
                                            K. Other Non-Road Engines                                           
----------------------------------------------------------------------------------------------------------------
1. Establish emission standards for small utility                                                               
 equipment (1).........................................            Y             N   .............            N 
2. Establish emission standards for new heavy duty                                                              
 construction equipment (1)............................            Y             Y   .............            Y 
3. Establish emission standards for off road                                                                    
 motorcycles (1).......................................            Y             Y              Y             Y 
----------------------------------------------------------------------------------------------------------------
                                            L. Miscellaneous Measures                                           
----------------------------------------------------------------------------------------------------------------
1. Expand PM-10 monitoring network (\2/3\).............            N   ............  .............            N 
2. Move state fair to a different time of the year (1).            N   ............  .............            N 
3. Winter daylight savings time (1)....................            N   ............  .............           N  
----------------------------------------------------------------------------------------------------------------
\1\EPA has no legal authority to enforce local measures, such as traffic and parking regulations, which are not 
  approved into the SIP. Most PM-10 air pollution regulations are separately listed in this table.              
\2\Dust control plans are a requirement for sources which are required to obtain a permit from the County, but  
  are not a requirement for unpermitted sources. A dust control plan is a method for identifying, implementing  
  and enforcing dust control measures for and on a particular source, rather than a dust control measure in and 
  of itself.                                                                                                    

5. RACM Criteria
    The General Preamble suggests three criteria for excluding measures 
as RACM: de minimis source, technological infeasibility, and the cost 
of control in the nonattainment area. EPA's proposed definitions for 
each of these criteria are described below.
    a. De Minimis Source. EPA proposes to rely on the criteria applied 
under its new source permitting programs (40 CFR 51.165(b)) as a guide 
in determining when a source category is de minimis for the purposes of 
determining whether RACM must be applied: a de minimis source or source 
category is one that contributes less than

[[Page 15932]]

5 g/3 of PM-10 to a location of expected 24-hour 
exceedances and 1 g/m3 to a location of expected 
annual violation. To be a considered a de minimis source for the 
purposes of this RACM analysis, the source had to be de minimis for 
both the 24-hour and annual standard. As discussed previously in 
section IV.B., focusing on what is reasonable and practicable for 
significant sources is consistent with the CAA's scheme of graduated 
controls for PM.
    EPA has used the results from the State's microscale plan to 
identify which source categories are significant and de minimis for the 
24-hour standard for the purposes of RACM analysis. As discussed in 
EPA's final action on the microscale plan (62 FR 41856), the 
significant source categories for the 24-hour standard are unpaved 
roads, unpaved parking lots, disturbed cleared areas (i.e., vacant 
lots), agricultural fields, and agricultural aprons. 62 FR 31031. De 
minimis source categories for the 24-hour standard are industrial 
yards, surface mining, other industrial activities, paved roads, 
trackout, and paved parking lots.
    To determine significant and de minimis sources for the annual 
standard for this RACM analysis, EPA has relied on the results at the 
Greenwood monitoring site in the State's Urban Airshed Model (UAM) 
simulation, performed as part of ongoing work for Maricopa's serious 
area PM-10 plan, see MAG Modeling TSD, Table 6.9. The complete list of 
significant and de minimis sources for this RACM determination can be 
found in Table 2 below. Where the air quality modeling provides only a 
single impact number for a group of source categories (e.g., ``other 
area sources'' which contains area source fuel combustion, open 
burning, and emissions from charbroiling), EPA has assumed that the 
impact of an individual source category is proportional to its presence 
in the inventory for that group of source categories. In total, the de 
minimis categories account for less than 10 percent of the total 
exceedance value at the Greenwood 
monitor.22-24,25
---------------------------------------------------------------------------

    \22-24\This de minimis RACM criterion is invoked here solely for 
the purposes of determining which source categories need RACM and 
not for determining which source categories need controls for 
attainment. See Section IV.B.
    \25\EPA has already approved RACM for some of the de minimis 
sources, e.g., major stationary sources, residential wood 
combustion, non-road engines). Also, EPA notes that some de minimis 
source categories already have substantial SIP-approved controls on 
them (e.g., clean fuels and inspection and maintenance program for 
on-road mobile sources) although EPA has not formally found these 
controls to be RACM under the moderate area PM-10 RACM requirement 
in section 189(a)(1)(C).

 Table 2.--Significant and De Minimis Source Categories for Determining 
                      RACM for the Annual Standard                      
------------------------------------------------------------------------
                                                               Annual   
                                                              impact at 
                                                                 the    
                  PM-10  Source category                      Greenwood 
                                                               Monitor  
                                                            (g/
                                                                 m3)    
------------------------------------------------------------------------
                      Significant Source Categories                     
------------------------------------------------------------------------
Paved road dust...........................................          20.0
Unpaved road dust.........................................           2.9
Construction/earthmoving..................................           5.4
Non-road engines..........................................           1.2
------------------------------------------------------------------------
                                                                        
                      De Minimis Source Categories                      
------------------------------------------------------------------------
On-road mobile sources:                                                 
    Gasoline-powered......................................           0.3
    Diesel-powered........................................           0.9
Agricultural dust.........................................           0.2
Residential wood combustion...............................           0.4
Other area sources:                                                     
    Fuel combustion.......................................           0.4
    Charbroiling..........................................           0.5
    Other.................................................           0.5
Other non-road engines:                                                 
    Locomotives...........................................           0.1
    Airport ground support................................           0.1
Major Point Sources.......................................           0.2
Windblown dust............................................           0.4
------------------------------------------------------------------------

    b. Technological Feasibility. As the term is proposed to be used 
here, technological feasibility means that the control measure is 
currently available and being implemented elsewhere and that the 
measure can achieve PM-10 emission reductions in Maricopa County prior 
to the attainment deadline of December 31, 2001. EPA has long held that 
it would not consider a measure ``reasonable'' if it could not be 
implemented on a schedule that would advance the date for attainment in 
the area. See 57 FR 13498, 13560.
    For some measures (e.g., trip reduction ordinances), the State has 
already implemented SIP-approved controls. For these measures, EPA has 
evaluated the potential emission reduction benefit of additional 
federal controls from a baseline that reflects the existing controls.
    Finally, one measure on the list, restrictions on blowers for 
landscaping, would in order to be effective require a complete ban on 
leaf blowers. EPA does not believe that, under the CAA's graduated 
level of controls for PM-10, that eliminating a source completely 
constitutes a reasonable level of control.
    c. Cost of Implementation. In considering the cost of implementing 
a measure in an area, the General Preamble suggests that in case of 
public sector sources and control measures, the cost evaluation should 
consider the impact of the reasonableness of the measures on the 
governmental entity that must bear the responsibility for their 
implementation. 57 FR 13541. This statement in the General Preamble is 
a recognition, as noted in section IV.B.,

[[Page 15933]]

that the regulatory scheme for PM-10 in subpart 4 establishes two 
graduated levels of control, RACM and BACM, depending on the severity 
of the air quality problem. As such, greater latitude is given 
responsible entities to determine what is feasible and practicable when 
selecting their initial RACM control strategy. Thus the nature and 
scope of a potential control measure, including such factors as the 
degree of capital expenditures required and lead-time needed for 
legislative consideration, operational and/or infrastructural 
development needs, etc., are appropriate determinants of what measures 
may be ``reasonably available.''
    In promulgating a FIP, EPA is the primary implementing entity. As 
such, EPA must evaluate the reasonableness of potential RACM based on 
its financial and resource capabilities (in the manner described above 
for other governmental entities) to implement the measure . The Agency 
notes that its duty to promulgate and implement FIPs is in addition to 
rather than a replacement of its other duties under the Clean Air Act. 
As such, where implementing a potental RACM FIP measure would require 
the Agency to expend substantial efforts to acquire needed resources, 
including financial resources, EPA could also take such factors into 
consideration in determining whether the measure is practicable and, 
thus, reasonable to implement.
    A general discussion of the above-described types of constraints in 
implementing measures for the Phoenix area can be found in the 1990 CO 
FIP proposal. 55 FR 41210. While EPA may undertake the necessary steps 
to acquire resources and funding, e.g., by diverting personnel and 
funds or by submitting budget supplement requests to Congress, to 
implement and enforce a FIP in Maricopa County or anywhere else in the 
nation, the feasibility of such efforts, depending on the nature and 
scope of the work needed to implement the proposed measure, may well 
exceed what may fairly be considered reasonable or practicable. EPA has 
also discussed generally the resource constraints associated with 
federal implementation of transportation control measures in its 
proposal of an ozone and CO FIP for the Los Angeles area. See 55 FR 
36458, 36517 (September 5, 1990).
    Examples of measures on the list that are generally not reasonably 
within EPA's current resource constraints to implement are measures 
which require substantial capital or operational expenditures. Examples 
of measures in this category include building high occupancy vehicle 
lanes, funding expansion of mass transit, and constructing substantial 
traffic flow improvements.
6. Application of RACM Criteria
    EPA applied these proposed RACM criteria to the 56 measures in 
Table 1 that were found to be appropriate for federal implementation. 
The results of this RACM screening are given in Table 3. Of the 56 
measures, 46 were eliminated: 17 because they apply to de minimis 
sources; 20 because a federal measure would not improve on the emission 
reduction benefit from a SIP-approved measure; 5 because the measure 
could not be feasibly implemented prior to the attainment date, one 
because the measure required elimination of the source completely which 
EPA believes is unreasonable, and 3 because of cost considerations. A 
more detailed discussion of EPA's justifications for rejecting 
potential RACM measures based on these RACM criteria can be found in 
the TSD for this proposed rulemaking.
    As seen from Table 3, ten measures remain after the application of 
the RACM criteria. These measures are a variety of potential fugitive 
dust controls for unpaved roads, unpaved parking lots, disturbed 
cleared land, and agriculture. Therefore, as described in detail in 
section V.A.7, EPA is proposing federal RACM measures to address these 
fugitive dust sources including a federal fugitive dust rule and an 
enforceable commitment for the agricultural sector.26
---------------------------------------------------------------------------

    \26\One significant source category for the annual standard, 
paved roads, is not currently being addressed comprehensively 
through SIP-approved RACM or proposed FIP RACM. While EPA analyzed 
40 potential measures for this source category (see categories A.1. 
and A.2. on Table 1), only one of these measures was found to be a 
FIP RACM. EPA notes, however, that the State has a number of SIP-
approved measures already in place, including a trip reduction 
program, that reduce emissions from this category.

                                        Table 3.--FIP RACM Evaluation\1\                                        
----------------------------------------------------------------------------------------------------------------
                                                                                      Reasonable                
              Source category and measure                De Minim is   Technically  implementation    FIP RACM  
                                                           Source       feasible         cost                   
----------------------------------------------------------------------------------------------------------------
                                A.1. Paved Road Dust--Reduce Dust (Silt) Loading                                
----------------------------------------------------------------------------------------------------------------
1. Pave, vegetate, or chemically stabilize access                                                               
 points where unpaved traffic surfaces adjoin paved                                                             
 roads (1)............................................            N             Y              Y              Y 
2. Require haul trucks to be covered (1)..............       Unk\2\           N-1   ..............            N 
3. Provide for traffic rerouting/rapid clean-up of                                                              
 temporary sources of dust (water erosion, track out,                                                           
 material spills) (1).................................          Unk           N-1   ..............            N 
5. Require curbing and pave or stabilize road                                                                   
 shoulders (1)........................................          Unk           N-1   ..............            N 
6. Provide for stormwater drainage to prevent water                                                             
 erosion onto paved roads (2/3).......................            N           N-1              N              N 
7. Mitigation of freeway construction impacts (1).....          Unk           N-1   ..............            N 
----------------------------------------------------------------------------------------------------------------
                               A.2. Paved Road Dust/Tailpipe Emissions--Reduce VMT                              
----------------------------------------------------------------------------------------------------------------
1. Implement short range transit improvements (2/3)...            N             Y              N              N 
2. Implement long range transit improvements (2/3)....            N           N-2              N              N 
3. Require exclusive bus lanes on arterials and                                                                 
 freeways (2/3).......................................            N           N-2              N              N 
4. Expand MAG rideshare program (2/3).................            N             Y              N              N 
5. Adopt trip reduction ordinance (1).................            N           N-1   ..............            N 
6. Establish a voluntary no drive days (1)............            N           N-1   ..............            N 
7. Establish an areawide public awareness program (1).            N           N-1   ..............            N 
8. Build/establish park and ride lots.................            N           N-1              N              N 
9. Provide employees financial incentives (e.g., zero                                                           
 bus fares) in lieu of parking (1)....................            N           N-1   ..............            N 

[[Page 15934]]

                                                                                                                
10. Require employers to provide preferential parking                                                           
 for car and van pools (1)............................            N           N-1   ..............            N 
12. Build HOV lanes on freeways (3)...................            N           N-1              N              N 
13. Build HOV lanes on arterials (3)..................            N           N-2              N              N 
14. Build HOV ramps which bypass metering signals (3).            N           N-1              N              N 
15. Promote increased bicycle use (3).................            N           N-1              N              N 
16. Provide or require bicycle travel (e.g., lanes)                                                             
 and support facilities (e.g., lockers and racks) (3).            N           N-1              N              N 
17. Promote pedestrian travel through provisions of                                                             
 pedestrian facilities (e.g. sidewalks) (3)...........            N           N-1              N              N 
18. Provide pedestrian overpasses (3).................            N           N-1              N              N 
19. Promote the use of/require employers to provide                                                             
 alternative work hours (1)...........................            N           N-1   ..............            N 
20. Promote the use of/require employers to provide                                                             
 alternative work weeks (1)...........................            N           N-1   ..............            N 
21. Promote the use of telecommuting (1)..............            N           N-1   ..............            N 
22. Promote the use of teleconferencing (1/2/3).......            N           N-1   ..............            N 
25. Require merchant to provide alternative                                                                     
 transportation incentives to customers (1)...........            N           N-2   ..............            N 
28. Impose fee on vehicles related to emissions (smog                                                           
 fees) (1)............................................            N           N-2   ..............            N 
----------------------------------------------------------------------------------------------------------------
                       B. On-Road Vehicle Exhaust--Tailpipe and Non-VMT Reduction Measures                      
----------------------------------------------------------------------------------------------------------------
1. Expand current I/M to all model years (1/2/3)......            Y   ............  ..............            N 
2. Expand the current I/M program state wide (1/2/3)..            Y   ............  ..............            N 
3. Expand the current I/M program county wide.........            Y   ............  ..............            N 
5. Require clean fuels for fleet vehicles.............            Y   ............  ..............            N 
6. CA new car standards...............................            Y   ............  ..............            N 
8. Scrap higher polluting vehicles (2/3)..............            Y   ............  ..............            N 
20. Alternative fuels for buses/electric shuttle buses                                                          
 (1)..................................................            Y   ............  ..............            N 
21. Emission controls on public diesel vehicles (1)...            Y   ............  ..............            N 
----------------------------------------------------------------------------------------------------------------
                           C. Dust from Unpaved Road/Parking Lot/Disturbed Vacant Lots                          
----------------------------------------------------------------------------------------------------------------
2. Require sources to submit dust control plans (1)...            N             Y              Y              Y 
3. Develop traffic reduction plans on unpaved roads                                                             
 (1)..................................................            N             Y              Y              Y 
4. Limit use of recreational vehicles on open land (1)            N             Y              Y              Y 
5. Pave or stabilize unpaved roads (1)................            N             Y              Y              Y 
6. Pave or stabilize unpaved parking areas (1)........            N             Y              Y              Y 
8. Require stabilization of wind erodible soils (1)...            N             Y              Y              Y 
9. Require windbreaks, watering, paving, vegetating                                                             
 for windblown dust (1)...............................            N             Y              Y              Y 
10. Restrict blowers for landscaping (1)..............         Unk.           N-3   ..............            N 
----------------------------------------------------------------------------------------------------------------
                                             D. Agricultural Sources                                            
----------------------------------------------------------------------------------------------------------------
1. Rely on soil conservation requirements (e.g.,                                                                
 conservation plans) of the Food Security Act (1).....            N             Y              Y              Y 
2. Require windbreaks for agricultural sources (1)....            N             Y              Y              Y 
----------------------------------------------------------------------------------------------------------------
                                                 I. Locomotives                                                 
----------------------------------------------------------------------------------------------------------------
2. Control switching locomotives (1)..................            Y   ............  ..............            N 
3. Require electrification of rail lines (1)..........            Y   ............  ..............            N 
----------------------------------------------------------------------------------------------------------------
                                      J. Airplanes/Airport Ground Equipment                                     
----------------------------------------------------------------------------------------------------------------
1. Centralized airport ground power systems (1).......            Y   ............  ..............            N 
2. Reduce emissions from airport ground access                                                                  
 vehicles (1).........................................            Y   ............  ..............            N 
3. Establish tighter emissions standards for new jet                                                            
 engines (1)..........................................            Y   ............  ..............            N 
4. Control emissions from aircraft and ground service                                                           
 vehicles (1).........................................            Y   ............  ..............            N 
5. Require replacement of high emitting aircraft (1)..            Y   ............  ..............            N 
----------------------------------------------------------------------------------------------------------------
                                            K. Other Non-Road Engines                                           
----------------------------------------------------------------------------------------------------------------
2. Establish emission standards for new heavy duty                                                              
 construction equipment (1)...........................            Y   ............  ..............            N 
3. Establish emission standards for off-road                                                                    
 motorcycles (1)......................................            Y   ............  ..............            N 
----------------------------------------------------------------------------------------------------------------
\1\Technological feasibility codes on Table 3 are:                                                              
N-1. Measure is already in place in local jurisdiction. Additional federal rule would not result in additional  
  emission reductions.                                                                                          
N-2. Measure is very unlikely to result in measurable emission reductions in the Phoenix area because technology
  is not available and/or demonstrated, technology will not be available prior to the attainment date, and/or   
  supporting infrastructure is absent (e.g., a viable transit system is necessary in order for merchant         
  transportation incentives to be effective).                                                                   
N-3. Measure involves elimination of the source and therefore does not represent a reasonable level of control. 
\2\While paved (i.e., re-entrained) road dust is clearly a significant source of PM-10 in the Phoenix           
  nonattainment area, the contribution of unpaved shoulders, material from haul trucks, all track out and       
  accidental spills to this source category is unknown.                                                         


[[Page 15935]]

    a. Commitment for Agricultural Sector. (1) Summary of Proposed 
Commitment and Approach EPA's RACM analysis above indicates that RACM 
controls are needed for agricultural sources of PM-10. Currently, RACM 
is not being fully implemented for agricultural fields and aprons in 
the Phoenix area.27-29 Therefore, federal measures are 
needed to reduce PM-10 from these sources.
---------------------------------------------------------------------------

    \27-29\Application of Rule 310 to agricultural sources including 
fields and aprons is affected by a provision in section 102 of the 
rule which incorporates A.R.S. 49-504.4. Section 102 provides that 
Rule 310 ``shall not be construed so as to prevent normal farm 
cultural practices.'' Therefore, applicability of the rule to such 
sources depends on the nature of the dust-generating operation. As 
such, Rule 310 applies to some operations on agricultural fields and 
aprons and not to others.
---------------------------------------------------------------------------

    EPA is proposing an enforceable commitment to adopt and implement 
RACM as required by CAA section 189(a)(1)(C) for the agricultural 
sector. In order to develop the RACM, as discussed below, EPA intends 
to use a stakeholder approach which, it is anticipated, will result in 
the development of best management practices (BMPs) that provide PM-10 
emission reductions from agricultural sources in the nonattainment 
area.
    (2) Background. The microscale plan30 demonstrated that 
wind-blown dust from agricultural fields and aprons (i.e., farm access 
roads and equipment turnaround areas) significantly contributes to 
exceedances of the 24-hour standard at the Gilbert and West Chandler 
monitoring sites. These sites are representative of the numerous 
agricultural-urban interface areas located in the nonattainment area.
---------------------------------------------------------------------------

    \30\In addition to EPA's standard AP-42 emission methodologies 
and some other prior special studies for particular source 
categories, the microscale study included field surveys, aerial 
photography, examination of activity logs, and interviews with 
source operators. The study resulted in a substantially better 
emissions inventory data than is usually available.
---------------------------------------------------------------------------

    The Gilbert monitoring site is located on the grounds of the City 
of Gilbert's wastewater treatment plant and has agricultural fields and 
aprons to its north, an unpaved and paved parking lots to the north and 
west, and a city park to the south. Modeling showed that windblown dust 
from agricultural fields and unpaved parking lots was the largest 
contributor to the exceedance at the Gilbert monitor. The West Chandler 
monitoring site is bordered on the west by agricultural fields and the 
right of way for the Price Road/Freeway, which was under construction 
in early 1995. Modeling showed that windblown dust, mainly from 
agricultural fields and road construction, was the largest contributor 
to the exceedance at the West Chandler monitor.
    There are approximately 600 growers farming approximately 300,000 
acres of land in Maricopa County. An estimated 63 percent of the 
agricultural activity in Maricopa County occurs within the 
nonattainment area. Upland cotton (112,000 acres), alfalfa (54,000 
acres), and durum wheat (45,000 acres) comprised over two-thirds of the 
crop acreage in Maricopa County during 1996. Cash receipts for crops 
grown in 1996 totaled over $440 million, ranking Maricopa County second 
in the state. The area is characterized by very low rainfall (7 inches 
per year) and desert conditions.
    Maricopa County is undergoing rapid urbanization with agricultural 
land being converted into other uses at a rate of approximately 6,000 
acres per year. As this urbanization continues, the amount of PM-10 
associated with agricultural lands will decrease because the amount of 
land being farmed within Maricopa County is shrinking. The 1996 Farm 
Bill has also affected farming practices in the Maricopa County 
nonattainment area. See 16 U.S.C. 3801 et seq. After 1994, land which 
had been set aside under a prior U.S. Department of Agriculture (USDA) 
program was placed in production (primarily alfalfa). The switch from 
unplanted set-aside to planted alfalfa resulted in a relatively small 
decrease in PM-10 emissions. Despite the conversion of agricultural 
lands to other uses and the small increase in agricultural land being 
put back into production, agricultural sources are expected to continue 
to contribute to PM-10 emissions for the foreseeable future.
    (3) RACM Analysis. EPA evaluated existing agriculture measures in 
the South Coast Air Basin (SCAB)31 to assess potential RACM 
for agriculture for the Phoenix nonattainment area.32 
However, it is important to note that because agricultural sources in 
the United States vary by factors such as regional climate, soil type, 
growing season, crop type, water availability, and relation to urban 
centers, each PM-10 agricultural strategy is uniquely based on local 
circumstances. Unlike many stationary sources, which can have many 
common design features, whether located in California or New Jersey, 
agricultural sources and activities vary greatly throughout the 
country.
---------------------------------------------------------------------------

    \31\EPA identified South Coast Air Quality Management District 
(SCAQMD) Rule 403.1--Wind Entrainment of Fugitive Dust. This rule 
applies to any activities which can generate fugitive dust when 
winds exceed twenty-five miles per hour (mph) in the Coachella 
Valley Planning PM-10 nonattainment area. Rule 403.1 requires that 
any person involved in activities which both occur in the Coachella 
Valley Blowsand Zone and are capable of generating fugitive dust to 
stabilize deposits using water or dust suppressants, or install wind 
breaks, and also restricts agricultural tilling when wind speeds 
exceed twenty-five mph and requires that inactive disturbed surface 
areas be stabilized using water or dust suppressants.
    EPA also identified SCAQMD 403--Fugitive Dust (amended February 
14, 1997), which requires any person generating fugitive dust from 
an active operation, open storage pile, or disturbed surface to 
implement RACM or BACM listed in the rule to minimize fugitive dust 
(e.g., apply chemical stabilizers on disturbed surface areas; apply 
water to unstabilized areas three times per day). Subject sources 
may submit a dust control plan in lieu of the control measures 
listed in the rule.
    Finally, EPA identified SCAQMD Rule 1186--PM10 Emissions From 
Paved and Unpaved Roads, and Livestock Operations, which is intended 
to reduce PM-10 entrained in the ambient air as a result of 
vehicular travel on paved and unpaved roads, and at livestock 
operations. The requirements affecting livestock operations include: 
cease hay grinding between 2 and 5 p.m. if visible emissions extend 
50 feet from the source; and treat unpaved access connections and 
unpaved feed access areas using either pavement, gravel, or asphalt.
    A more detailed discussion of the provisions found in these 
rules can be found in the Technical Support Document for today's 
proposed action.
    \32\EPA recognizes the role of USDA's Natural Resources 
Conservation Service (NRCS) in working with individual growers to 
voluntarily develop Soil Conservation Plans (SCPs). Because SCPs in 
the Maricopa County area are voluntary (approximately one-third of 
the growers have a SCP), grower-initiated, and have very minimal air 
quality benefits as currently designed, the use of SCPs in Maricopa 
County was determined to not meet RACM and thus not considered a 
viable option for the proposed FIP. See 57 FR 13498, 13541. In 
addition, representatives from NRCS and the Arizona Farm Bureau 
Federation have indicated to EPA that they do not support using SCPs 
for RACM.
---------------------------------------------------------------------------

    With respect to Phoenix and the Los Angeles area, EPA determined 
that the two areas differ in a number of key characteristics (e.g., 
crops grown, soil types, climate, and number of growers affected). In 
assessing RACM for agricultural sources, EPA considered the uniqueness 
of the myriad factors affecting agricultural activity in the 
nonattainment area. 57 FR 13498, 13540-13541. Based on this initial 
screening, EPA decided that it would not be responsible to propose the 
SCAQMD rules at this time because the Agency could not reasonably 
conclude that their implementation would in fact result in air quality 
benefits for the nonattainment area. Instead, the SCAQMD rules will be 
further assessed as part of the BMP development process. This process 
will allow EPA to take advantage of various local and national 
agricultural expertise to more fully evaluate whether the SCAQMD rules, 
portions thereof, or other unique emission reduction strategies would 
contribute to attainment and, therefore, should be applied in Maricopa 
County.

[[Page 15936]]

(4) Proposed Commitment
    (i) Discussions With Stakeholders. In recognition of the need to 
address agriculture's contribution to the PM-10 exceedences, the 
microscale plan included a March 27, 1997 letter signed by the Arizona 
Department of Environmental Quality (ADEQ), MCESD and the NRCS. The 
letter stated the intent of the three agencies to work cooperatively 
toward strategies that address PM-10 emissions from agricultural lands 
within Maricopa County. The three agencies sponsored meetings in March 
and May, 1997 which brought stakeholders together to discuss 
agriculture and PM-10. At the same time, and into the summer of 1997, 
MAG was working with the Maricopa County Farm Bureau on possible 
emission controls for agricultural lands as part of the PM-10 serious 
area plan development. Also during the summer of 1997, EPA held 
meetings with ADEQ, MAG, MCESD, and NRCS to discuss potential 
strategies to reduce PM-10 from agricultural lands.
    Because there were two separate ongoing efforts with respect to PM-
10 emissions from agricultural sources, as described above, EPA used 
these meetings to keep apprised of the progress of the two efforts, as 
well as to discuss implementation issues related to agricultural 
control measures. The MAG discussions with the Maricopa Farm Bureau 
resulted in the identification of several potential PM-10 control 
measures by early fall, 1997. These measures were voted on and approved 
by the Maricopa County Farm Bureau Board in September, 1997. At that 
time, EPA decided that a joint discussion with ADEQ, MCSED, MAG, NRCS, 
and the Farm Bureau would be beneficial to both the FIP and SIP 
processes.
    Thereafter, EPA contacted the NRCS, the Arizona Farm Bureau 
Federation, and other stakeholders and arranged for a November 12-14, 
1997 tour of agricultural activities to better understand their impact 
in Maricopa County. Several meetings were held with these same 
stakeholders. The meetings provided an opportunity for EPA to discuss 
the upcoming FIP proposal and the need to work 
collaboratively33 on strategies addressing agriculture and 
PM-10. The tour and subsequent meetings allowed EPA to work directly 
with the leaders in the Maricopa County agricultural and regulatory 
community and set the stage for future discussions on possible 
strategies for reducing PM-10 from agriculture in the area. Subsequent 
meetings on December 2 and 16, 1997 among EPA, Farm Bureau 
representatives, farmers, NRCS, ADEQ, MCESD, and MAG resulted in a 
general consensus on using a BMP approach to develop measures to reduce 
PM-10 from agriculture. On January 7, 1998, EPA Region IX sent a letter 
to the Maricopa County Farm Bureau stating EPA's intention to include 
the BMP approach in the proposed FIP. On January 21, 1998, the Maricopa 
County Farm Bureau sent a letter to EPA Region IX indicating their 
general support for the BMP approach. The letter also provided their 
recommendations on milestones and timeframe needed for a successful BMP 
approach.
---------------------------------------------------------------------------

    \33\In early 1997, the USDA's Agricultural Air Quality Task 
Force began discussions with EPA on issues related to agriculture 
and air quality. Over the course of the year, the Task Force drafted 
a Memorandum of Understanding (MOU) between USDA and EPA that 
establishs a formal relationship for sharing expertise and involving 
the agricultural community in air quality issues. The MOU was signed 
by EPA on February 25, 1998 and by the USDA on 1/14/98. EPA believes 
that the BMP approach follows the cooperative spirit outlined in the 
MOU.
---------------------------------------------------------------------------

    (ii) BMP Approach. The proposed BMP approach for addressing PM-10 
from agricultural sources could be modeled after an analogous BMP 
approach used for managing fertilizer applications and protecting 
groundwater in Arizona. Under the nitrogen fertilizer BMP program, 
legislation was passed in the late 1980s giving the Director of ADEQ 
the authority to oversee the development and implementation of BMPs. An 
Advisory Committee, comprised of representatives from key government 
agencies, universities, and the agricultural community was established 
to develop and recommend BMPs for adoption by ADEQ. After adoption of 
the BMPs, supplemental guidance documents were developed by the 
University of Arizona to assist growers, and an extensive grower 
education campaign was undertaken to increase the likelihood for 
successful BMP implementation. The BMPs eventually became part of the 
Arizona Administrative Code (Title 18, Chapter 9, Article 2), which 
requires that all persons engaged in the application of nitrogen 
fertilizers be issued a general permit and comply with the six 
agricultural BMPs stated in the law. A similar approach was also used 
to develop BMPs for concentrated animal feeding operations in Arizona.
    (iii) FIP Proposal. EPA is proposing an enforceable commitment to 
adopt and implement RACM to reduce PM-10 emissions from agricultural 
sources. The proposed FIP commitment includes a series of enforceable 
milestones and due dates listed in Table 4 to assure adoption and 
implementation of RACM. EPA would initially convene a stakeholder-based 
process to begin formal development of draft BMPs. Stakeholder groups 
represented will likely include but not be limited to the Arizona Farm 
Bureau Federation, Maricopa County Farm Bureau, ADEQ, MAG, MCESD, NRCS, 
Cooperative Extension, the University of Arizona, tribes, and 
environmental and/or public health organizations. This effort would 
build upon the stakeholder-based discussions which occurred in 1997 and 
early 1998. By September 1998, the stakeholders would begin to draft 
BMPs. Potential BMPs likely to be considered include but are not 
limited to: windbreaks, vegetative covers, chemical or physical soil 
stabilizers, improved tillage practices, tillage limitations during 
high wind events, speed reductions on unpaved or untreated farm roads, 
and tillage pre-irrigation. The milestones by which EPA proposes to 
complete various aspects of BMP development and implementation are as 
follows. By September 1999, EPA will have drafted the BMPs developed 
for official public comment, which will occur through a Notice of 
Proposed Rulemaking. After public comment and additional stakeholder 
meetings, EPA will finalize the BMPs in a Notice of Final Rulemaking. 
In June 2000, BMP implementation will begin with an extensive 
collaborative public outreach and education campaign. Guidance 
documents would be developed to assist growers with implementation of 
the BMPs. Compliance assistance would also be a key element of the BMP 
program.

Table 4.--Proposed Deadlines for EPA Adoption/Implementation of RACM for
                         Agriculture in Maricopa                        
------------------------------------------------------------------------
                  Milestones                            Due date        
------------------------------------------------------------------------
Notice of Proposed Rulemaking for RACM.......  September 1999.          
Notice of Final Rulemaking for RACM..........  April 2000.              

[[Page 15937]]

                                                                        
RACM implementation..........................  June 2000.               
------------------------------------------------------------------------

(5) FIP Replacement.
    Although EPA is only required in the FIP to meet the CAA RACM 
requirement, the State is expected, as required for PM-10 serious 
nonattainment areas, to develop BACM for agricultural sources. The 
State expects the BACM developed for the serious area plan to also 
Satisfy any remaining CAA RACM requirements. EPA is committed to 
working with ADEQ and the other stakeholders to develop a SIP measure 
to replace the proposed enforceable commitment.
    While EPA's intended BMP approach is designed to meet the RACM 
requirement, the Agency believes it can serve as a potential starting 
point and model for the development of a State-led SIP process for 
addressing BACM for agricultural sources. Thus, the stakeholders could 
potentially build upon the BMP approach initiated for the FIP to 
address both RACM and BACM requirements for the agricultural sector in 
the SIP. The Arizona Farm Bureau Federation, the Maricopa County Farm 
Bureau, NRCS, ADEQ, and other regulatory agencies are currently working 
collaboratively to develop a State-led BMP process for that purpose. 
EPA strongly endorses such a process. However, because EPA has not 
received to date an adequate SIP submittal addressing the 
implementation of RACM by June 2000 for agricultural sources of PM-10, 
EPA is proposing an enforceable commitment for those sources as 
described above.
    b. Rule for Unpaved Parking Lots, Unpaved Roads and Vacant Lots. 
Fugitive dust from unpaved parking lots and unpaved roads is primarily 
caused by vehicle traffic. When vehicles travel over unpaved surfaces, 
they raise the silt content (i.e., grind up dirt so as to result in a 
greater abundance of finer particles). The more vehicles (and the 
faster they travel) on unpaved surfaces, the more PM-10 is stirred up 
in clouds of fugitive dust.
    On vacant lots, fugitive dust emissions are caused by virtually any 
activity which disturbs an otherwise naturally stable parcel of land, 
including earth-moving activities, weed abatement, material dumping and 
vehicle traffic. Once disturbed, the vacant lot may continuously 
generate dust until it is restabilized. Since wind conditions affect 
the amount of dust raised on vacant lots, PM-10 emission impacts may 
not be fully realized until several days following a disturbance.
    MCESD's Rule 310 requires RACM for fugitive dust sources; however, 
EPA has determined that the County does not enforce the rule for three 
source categories within the Phoenix PM-10 nonattainment area: unpaved 
parking lots, unpaved roads and vacant lots. As a result, EPA is having 
to fulfill the role of primary enforcer of the RACM requirement for 
these sources and has developed its own proposed rule addressing RACM 
for these sources.
    EPA's regional office in San Francisco, California (EPA Region 9) 
will have primary responsibility for enforcement of the proposed FIP 
rule. Given the difficulties that Region 9 will inevitably face in 
enforcing the RACM requirement in Arizona, EPA has designed a RACM rule 
that ensures EPA enforcement of the rule will be practicable. 
Furthermore, EPA believes that the proposed rule will be useful to 
MCESD in future SIP efforts to control dust from these sources.
    In general, EPA believes that all of the RACM requirements of the 
proposed FIP rule can also be required through enforcement of Rule 310. 
However, the rule's lack of specificity makes it more likely that the 
agency enforcing the rule will routinely be called upon to address 
which RACM should be applied to which source categories. By addressing 
this issue in the FIP rule itself through detailing specific RACM 
requirements, EPA hopes to reduce the extent to which sources and 
others may have to consult with the Agency to determine which RACM are 
appropriate for a particular source or source category.
    The only proposed FIP rule requirement that is not required in Rule 
310 is a recordkeeping requirement for owners/operators to maintain 
records of controls implemented on unpaved roads, unpaved parking lots, 
and vacant lots in order for EPA to ensure compliance with the 
rule.34 The proposed recordkeeping requirements in the FIP 
rule are simple and straightforward. In many cases, the owner/operator 
need only retain a purchase receipt or contractor work order for the 
controls implemented. More information is required when chemical 
stabilization is applied as a control measure, however, this 
information is readily available from vendors or easily determined at 
the time of application.
---------------------------------------------------------------------------

    \34\Rule 310 only requires recordkeeping for permitted dust-
generating operations.
---------------------------------------------------------------------------

    (1) Summary of Proposed Rule. In developing the proposed FIP rule, 
EPA utilized the RACM in Rule 310 while drawing upon several additional 
sources to increase specificity of the measures. A detailed discussion 
of EPA determinations and references for the proposed rule can be found 
in the Technical Support Document. Specific requirements of the 
proposed rule are summarized below.
    Unpaved parking lots: Any owners/operators of unpaved parking lots 
greater than 5,000 square feet are required to pave, chemically 
stabilize, or apply gravel to the lot within eight months of the rule's 
effective date. For unpaved parking lots that are used no more than 35 
days per year, owners/operators may choose to apply chemical 
stabilizers within 20 days prior to any day in which over 100 vehicles 
enter the lot.
    Unpaved roads: Any owners/operators of existing public unpaved 
roads with average daily trip volumes of 150 vehicles or greater are 
required to pave, chemically stabilize, or apply gravel to the unpaved 
road by June 10, 2000.
    Vacant lots: (1) A Dust Control Plan (as described in section 503) 
is required for weed abatement operations on vacant lots that disturb 
0.10 acres or more of soil by blading, disking, plowing under or other 
means (excluding mowing, cutting or similar processes in which soil is 
not disturbed), unless such operations receive an approved permit from 
Maricopa County Environmental Services Department. (2) Any owners/
operators of an urban or suburban open area vacant lot with 0.10 acres 
or more of disturbed surface area which is unused or undeveloped for 
more than 15 days are required to establish vegetation, apply dust 
suppressants, restore to a natural state, or apply gravel to all 
disturbed surfaces within eight months following the effective date of 
the proposed rule or within eight months following the initial 15 day

[[Page 15938]]

period of inactivity, whichever is later. (3) Any owners/operators of 
an urban or suburban open area vacant lot which has a disturbed surface 
due to motor vehicles (including off-road vehicles) are required to 
place signs, fencing, shrubs, trees, or cement barriers to prohibit 
vehicle entry along the access perimeter.
    The threshold level of 0.10 acres for weed abatement and disturbed 
surface areas is the same threshold level for the permitting of 
construction sites in Rule 310.35 Currently Rule 310 does 
not contain a threshold exemption for vacant lots. EPA is requesting 
comments on whether the 0.1 acre threshold is the appropriate threshold 
for determining when controls on vacant lots is required.
---------------------------------------------------------------------------

    \35\MCESD is currently preparing a revision to Rule 310 which 
would require dust control plans for weed abatement operations that 
disturb soil surfaces of 0.1 acres or greater.
---------------------------------------------------------------------------

    All categories: As an alternative to compliance with any of the FIP 
rule requirements (with the exception of the weed abatement provision), 
owners/operators may use alternative control measures approved by EPA. 
Proposed alternative control measures must be submitted to EPA for 
approval prior to the rule's deadline for RACM implementation for the 
source. Should EPA disapprove an alternative control measure, the 
owner/operator must begin implementing RACM as required in the rule no 
later than 60 days after receiving notice of disapproval.
    Recordkeeping: Owners/operators are required to maintain records of 
controls implemented on unpaved roads, unpaved parking lots, and vacant 
lots.
    (2) Discussion. The proposed FIP rule includes three to four RACM 
options for each source category. In order to ensure that emission 
reductions are achieved, the FIP rule only specifies control measures 
which have a reasonably high level of certainty in their control 
effectiveness and enforcement. However, EPA is willing to consider 
other measures, and is therefore allowing submittal of alternative 
control measures for any of the source categories subject to EPA 
approval.
    Surveys of fugitive dust sources and control measures are required 
to be conducted by EPA or its contractor in the proposed FIP rule in 
order to improve knowledge of the universe of sources and provide 
feedback on the rule's effectiveness. The surveys will enable 
regulators to better estimate the contribution of unpaved roads, 
unpaved parking lots and vacant lots to Maricopa County's PM-10 
inventory, identify control measures that are the most frequently 
implemented, and study the effectiveness of these measures in 
controlling fugitive dust.
    Tests in order to determine compliance with the proposed FIP rule 
would be conducted by EPA or its contractor, and do not pose additional 
requirements on sources subject to the rule. Implementation of some 
control measures, such as paving unpaved roads, are obvious upon 
inspection and tests are not necessary to determine compliance. For 
other control measures, such as application of chemical stabilizers and 
gravel, a test is needed to determine whether the surface is 
sufficiently stabilized to prevent or minimize fugitive dust emissions.
    For determining whether unpaved roads and unpaved parking lots are 
stabilized, EPA is proposing visible opacity test methods associated 
with vehicle use (Reference Method 9, Methods 203A, 203B, and 203C), 
with opacity readings conducted according to 203C. These methods 
incorporate a fugitive dust element to Reference Method 9, which is 
most appropriate for measuring emissions from stationary sources of PM-
10. Method 203C allows ``instantaneous'' readings averaged over a 
period of one minute, taken at 5 second intervals. EPA first proposed 
Reference Method 9, Methods 203 A, B, and C in 1993 (Appendix M, part 
51) and has incorporated public comments into the test methods. While 
EPA has not yet promulgated the methods, for purposes of federal 
enforcement of the FIP rule, they can be used as credible evidence 
until such time as EPA publishes a final rulemaking for the test 
methods (40 CFR part 52.12).
    For determining whether vacant lots have stabilized surfaces, EPA 
is proposing and requesting comment on test methods concerning visible 
crusts, vegetation, and threshold friction velocity of soil samples. 
Information on test methods proposed for this FIP is available in the 
TSD and the rulemaking docket.
    The proposed FIP rule does not preclude the right of any State or 
locality to adopt or enforce an emission standard or limitation which 
is more stringent than this rule (Clean Air Act section 116).
    (3) Compliance Approach. Upon promulgation of the FIP, EPA will 
implement its rule for unpaved parking lots, unpaved roads, and vacant 
lots. Thus, EPA will take on responsibilities that are normally 
performed by the local air quality regulatory agency, in this case, 
MCESD. These responsibilities would include such activities as: 
refining EPA's information on the universe of sources subject to the 
rule, developing an outreach/compliance assistance program for the 
affected community, inspecting sources subject to the rule, and 
following up with an appropriate enforcement response in the event of 
rule violations.
    Although the cities in the Phoenix area have provided information 
on the sources within their jurisdictions, EPA will be using 
contractual assistance to obtain additional information on the sources 
subject to the FIP rule. This information will be used by EPA to 
perform the surveys described above, to evaluate the rule's 
effectiveness, and to identify sources for potential inspections. This 
information can also be used (and EPA will encourage its use) by 
Maricopa County to better implement Rule 310.
    EPA will be implementing the FIP rule by providing resources 
directly from the Regional Office in San Francisco. Working with the 
information provided by the contractor, Region 9 will develop a 
compliance assistance strategy that will ensure that sources subject to 
the FIP rule are informed about the rule, and understand how the rule 
applies to them, what their compliance options are, and the need to 
comply with the provisions in the rule. Once EPA compliance assistance 
efforts are underway, EPA will inspect these sources for compliance 
with the FIP rule.
    In addition, EPA exercises a traditional oversight role over state 
and local air quality programs by making periodic visits to the states 
within Region 9 and conducting joint inspections with the state and/or 
local regulatory agencies. These joint inspections can cover a variety 
of sources, and, in the future, will include sources covered by the FIP 
rule.
    Also, because MCESD does not have sufficient resources to enforce 
Rule 310 for unpaved roads, unpaved parking lots, and vacant lots, EPA 
intends to provide two additional inspection resources to MCESD by 
supplementing the MCESD CAA section 105 grant in October 1998. These 
additional inspectors will perform inspections for EPA with respect to 
the three source categories subject to the FIP Rule. These additional 
resources will be provided to MCESD as long as the FIP is in place.
    (4) Replacement of FIP Rule. MCESD is currently trying to obtain 
additional resources to expand implementation of Rule 310. If MCESD 
obtains the additional resources and is able to develop an enforcement 
strategy for the vacant lot, unpaved parking lot and unpaved road 
sources covered by the FIP rule, this strategy may be submitted to EPA 
for approval as meeting the

[[Page 15939]]

CAA's RACM requirement for these sources. As part of any implementation 
strategy that MCESD submits for EPA approval, the County will need to 
provide evidence that it has adequate resources of its own to ensure 
that Rule 310 is fully enforced for all fugitive dust sources. If 
approved, such a strategy will allow EPA to rescind its FIP rule.

B. Impracticability Demonstration.

    The Clean Air Act requires moderate PM-10 nonattainment areas to 
demonstrate attainment of the PM-10 annual and 24-hour standards, or to 
show that attainment by December 31, 2001 is impracticable (see section 
IV.B. of this notice). For this proposed FIP, EPA is making the latter 
demonstration. Based on modeling work performed by the State, existing 
State controls together with the RACM being proposed by EPA are not 
sufficient for attainment of either the 24-hour or the annual PM-10 
standard by December 31, 2001.
1. Annual Standard
    For the annual standard attainment analysis, EPA relied on the 
State's simulation of the 1995 year found in the MAG Modeling TSD which 
was performed as part of ongoing work for Maricopa's PM-10 serious area 
plan. This work used a variant of the Urban Airshed Model (UAM), which 
is the EPA-recommended model for attainment demonstrations for ozone 
and carbon monoxide, though it can be used to model any pollutant. The 
UAM results were scaled using factors derived from observed PM-10 
concentrations and from emissions projected to 2001. Because the 
Greenwood monitoring site had the highest simulated annual 
concentrations, EPA has used this site as the basis for the annual 
standard impracticability demonstration.
    As can be seen in Table 5, even assuming 100 percent control for 
sources subject to the proposed FIP rule (an unrealistic level of 
control, actual control levels will be less36), simulated 
concentrations are still over the annual standard of 50 g/
m\3\. Thus, EPA proposes to find that attainment of the annual PM-10 
standard is impracticable with the implementation of RACM.

                            Table 5.--Annual Standard Impracticability Demonstration                            
----------------------------------------------------------------------------------------------------------------
                                                                       Concentration               Concentration
                                                                         after SIP      Maximum      after FIP  
                           Source category                                controls      possible      controls  
                                                                        g/     control     g/ 
                                                                            m\3\       (percent)        m\3\    
----------------------------------------------------------------------------------------------------------------
Paved road dust......................................................          20.0   ...........          20.0 
Unpaved road dust....................................................           2.9           100           0.0 
Gasoline and Diesel vehicle exhaust..................................           1.2   ...........           1.2 
Agricultural dust....................................................           0.2           100           0.0 
Other area sources...................................................           1.4   ...........           1.4 
Residential wood combustion..........................................           0.4   ...........           0.4 
Construction/earth moving............................................           5.4   ...........           5.4 
Construction equipment, locomotives, other non-road engines..........           1.4   ...........           1.4 
Major point sources..................................................           0.2   ...........           0.2 
Windblown dust.......................................................           0.4           100           0.0 
Anthropogenic Total..................................................          33.5   ...........          30.0 
Background...........................................................            22   ...........            22 
                                                                      ------------------------------------------
      Total..........................................................          55.5   ...........          52.0 
----------------------------------------------------------------------------------------------------------------

2. 24-hour Standard
    For its 24-hour standard attainment analysis, EPA relied on the 
modeling in Arizona's microscale plan. This modeling used the ISCST 
(Industrial Source Complex, Short Term) model, an EPA guideline model 
often used for stationary source permit applications, and well-suited 
to the locally-driven exceedances that were the focus of the microscale 
plan. ISCST was used to simulate PM-10 concentrations at representative 
sites subject to emissions from various source types and at which 24-
hour exceedances had been observed. These monitoring sites were: 1) 
Salt River, in an industrial area; 2) Gilbert, affected by agricultural 
and unpaved parking lot fugitive dust emissions; 3) Maryvale, with 
disturbed cleared areas nearby due to construction of a park; and 4) 
West Chandler, near a highway construction project. These sites were 
selected to represent a variety of conditions within the Maricopa 
nonattainment area.
---------------------------------------------------------------------------

    \36\Estimated regional emission reductions from the proposed FIP 
rule are discussed in Section V.C.1.
---------------------------------------------------------------------------

    The microscale plan demonstrated attainment at the Salt River and 
Maryvale sites, and EPA approved the attainment demonstrations at these 
sites at the time it took final action on the microscale plan. 62 FR 
41856. The microscale plan did not demonstrate attainment at the West 
Chandler and Gilbert sites. These sites will be addressed here.
    The proposed FIP rule requires RACM for unpaved roads, vacant lots, 
and unpaved parking lots. These sources in total contribute 25 percent 
of the emissions to the exceedance at the Gilbert site and just 1 
percent of the emissions to the exceedance at the West Chandler site. 
(For both sites, fugitive dust from agricultural sources is the largest 
contributor to the exceedances.) The proposed FIP rule has a 
substantial impact for the Gilbert site, reducing ambient 
concentrations from 213 to 176 g/m\3\ but much less effect at 
West Chandler, reducing concentrations from 332 to just 316 g/
m\3\. See Table 6. Because the proposed RACM do not result in 
attainment at either site, EPA is proposing to find that attainment of 
the 24-hour standard is impracticable with the implementation of RACM.
    As can be seen from Table 6, attainment at both sites will require 
substantial reductions from agricultural sources in addition to 
reductions from unpaved roads, unpaved parking lots, and vacant lots. 
While reductions from agricultural sources are expected through the 
implementation of BMPs by 2001, EPA is unable to quantify the impact of 
these BMPs at this time because they have not been defined sufficiently 
to determine the expected level of control. Once the BMPs have been 
defined, EPA will better be able to estimate reductions from 
agricultural sources and will revisit any final impracticability 
demonstration for the 24-hour standard and modify the demonstrations as 
necessary.

[[Page 15940]]



                     Table 6.--Impracticability Demonstration for the 24-hour PM-10 Standard                    
----------------------------------------------------------------------------------------------------------------
                                               Concentration after SIP                  Concentration after FIP 
                                               controls g/m3    FIP control    controls g/m3  
              Source category               ----------------------------  (percent)  ---------------------------
                                               Chandler       Gilbert                   Chandler       Gilbert  
----------------------------------------------------------------------------------------------------------------
Agricultural fields........................         194.7        ----           ----         194.7        ----  
Agricultural aprons........................          21.7          55.6         ----          21.7          55.6
Road construction..........................           6.9        ----           ----           6.9        ----  
Unpaved roads..............................           0.5           0.5           64           0.2           0.2
Paved Roads................................           0.2           1.6         ----           0.2           1.6
Unpaved parking lots.......................  ............          51.3           56  ............          22.6
Vacant lots................................          28.1          14.5           56          12.4           6.4
Anthropogenic Total........................         252.1         123.4  ...........         236.1          86.3
Background.................................          80            90    ...........          80            90  
                                            --------------------------------------------------------------------
    Total..................................         332.1         213.4  ...........         316.1         176.3
----------------------------------------------------------------------------------------------------------------

    See section V.C. immediately below for a discussion of the 
estimated emission reductions from the FIP control measures.

C. Reasonable Further Progress (RFP) Demonstration

    As discussed previously in Section IV.C. of this preamble, EPA 
interprets the RFP requirement for areas demonstrating impracticability 
as being met by a showing that all RACM will be implemented and that 
the implementation of all RACM has resulted in incremental emission 
reductions below pre-implementation levels. For the purposes of this 
proposed RFP demonstration, pre-implementation levels are 1998 emission 
levels, the promulgation year for this FIP. Because CAA section 171(1) 
defines RFP reductions as being ``for the purpose of ensuring 
attainment* * *by the applicable attainment date,'' post-implementation 
levels are 2001 emission levels, the statutory attainment 
year.37
---------------------------------------------------------------------------

    \37\The 1998 emission levels also include the implementation of 
improved controls on construction sources that were approved as BACM 
in the microscale plan and were to be implemented by mid-1997. No 
increase in control effectiveness after 1998 is expected from these 
State BACM measures or from other approved State RACM measures; 
therefore, the RFP demonstration proposed here only addresses the 
incremental reductions resulting from the proposed FIP measures.
---------------------------------------------------------------------------

    RFP is demonstrated separately for the annual and 24-hour standards 
because the mix of sources contributing to the annual standard 
exceedances differs from that contributing to the 24-hour exceedances. 
In addition, since PM-10 exceedances are related almost entirely to 
primarily-emitted PM-10, only emissions of primarily-emitted PM-10 are 
evaluated for RFP.
1. Annual Standard
    The proposed RFP demonstration for the annual standard is 
summarized here and in Table 7. A complete discussion of the RFP 
demonstration can be found in the TSD for this proposed action.
    Emission levels for 1998 and 2001 were calculated by growing 
emissions from the emission inventory base year of 1994 and the 
modeling year of 1995 based on growth factors contained in the MAG 
Modeling TSD and by incorporating reductions from approved State RACM 
and BACM controls. Emissions levels for 2001 also reflect the estimated 
emission reductions from the proposed FIP rule for unpaved roads. The 
estimated effectiveness of controls on unpaved roads, 80 percent, was 
based on the research done for the microscale plan on the effectiveness 
of controls for unpaved parking (see Table 4-1 in the final Microscale 
Plan) and assumes a rule effectiveness of 80 percent per EPA's guidance 
and that 90 percent of the VMT on unpaved roads will be impacted by the 
FIP rule. 57 FR 13503.
    The proposed annual RFP demonstration does not include emission 
reductions from the implementation of the proposed FIP rule for unpaved 
parking lots and vacant lots. Although emission reductions are expected 
from these sources, there currently is insufficient information on the 
number of unpaved parking lots and vacant lots that will be subject to 
the FIP to calculate an annual emission reduction. Information from the 
surveys EPA will perform after promulgation of the rule will help in 
quantifying emission reductions from these sources. In addition, while 
reductions from agricultural sources are also expected by 2001, no 
emission reductions were assumed in the proposed RFP demonstration for 
agricultural sources because the ultimate RACM have not been defined 
sufficiently to determine the expected level of control.
    As described in section V.A.7.b., the FIP rule as proposed requires 
phased implementation with final implementation no later than June, 
2000: existing vacant lots and unpaved parking lots are required to 
comply within 8 months of the effective date of the final rule 
(approximately April 1999) and unpaved roads are required to comply by 
June, 2000. Therefore, full implementation of the measure by 2001 can 
be assumed. A more detailed discussion of the proposed annual standard 
RFP demonstration can be found in the TSD for this action.
    As can be seen from Table 7, the emission reductions from the 
proposed FIP measure for unpaved roads is sufficient to assure an 
incremental emission reduction between 1998 and 2001 and additional 
reductions expected from unpaved parking lots, vacant lots, and 
agricultural sources will also contribute to this incremental emission 
reduction; therefore, EPA proposes to determine that the FIP assures 
RFP for the annual standard.

           Table 7.--RFP Demonstration for the Annual Standard          
------------------------------------------------------------------------
                                                               Total PM-
                                                                   10   
                             Year                              emissions
                                                                 metric 
                                                               tons/year
------------------------------------------------------------------------
1998.........................................................     61,024
2001.........................................................     54,256
------------------------------------------------------------------------

2. 24-hour Standard
    For the 24-hour standard, EPA evaluated RFP only for the Gilbert 
and West Chandler sites, having already approved the RFP demonstrations 
at the Maryvale and Salt River sites as part of its action on the 
microscale plan. 62 FR 41856. For these proposed RFP demonstrations, 
source activity at each monitor was assumed to be unchanged

[[Page 15941]]

from the 1995 levels determined in the microscale plan.38
    As with the annual standard demonstration, 1998 emission levels 
were adjusted to reflect implementation of the improved controls on 
construction sources and 2001 emissions levels to reflect the estimated 
emission reductions from the proposed FIP rule for unpaved roads, 
unpaved parking lots, and vacant lots. Emission reductions estimates 
are again based on the research done for the microscale plan and assume 
a rule effectiveness of 80 percent per EPA's guidance. For unpaved 
roads, a control effectiveness of 80 percent is assumed. For vacant 
lots and unpaved parking lots, a control effectiveness of 70 percent is 
assumed. As with the annual standard, no emission reductions were 
assumed for agricultural sources. A more detailed analysis of the 
proposed RFP demonstrations for the Gilbert and West Chandler monitors 
can be found in the TSD for this proposal.
    a. Gilbert Monitoring Site. The 24-hour exceedances at the Gilbert 
monitor are impacted by emissions from agricultural aprons, disturbed 
cleared lands (i.e., vacant lots), unpaved parking lots, and paved 
roads. 62 FR 31031. As can be seen from Table 8, the emission 
reductions from the proposed FIP rule for unpaved parking lots and 
vacant lots are sufficient to assure incremental emission reductions 
between 1998 and 2001 at the Gilbert monitoring sites; therefore, EPA 
proposes to determine that the proposed FIP assures RFP for the 24-hour 
standard at the Gilbert monitor.

                  Table 8.--RFP Demonstration for the 24-hour Standard--Gilbert Monitoring Site                 
----------------------------------------------------------------------------------------------------------------
                                                                              1998                       2001   
                            Source categories                              Emissions    FIP Control   Emissions 
                                                                            (kg/day)     (percent)     (kg/day) 
----------------------------------------------------------------------------------------------------------------
Agriculture aprons......................................................          165          0             165
Vacant lots.............................................................           76          0.56           33
Unpaved parking lots....................................................          190          0.56           84
Paved roads.............................................................            5          0               5
                                                                         ---------------------------------------
      Total.............................................................          436  ............          287
----------------------------------------------------------------------------------------------------------------

    b. West Chandler Monitoring Site.
    The 24-hour exceedances at the West Chandler monitor are impacted 
by emissions from agricultural fields, agricultural aprons, road 
construction, disturbed cleared lands (i.e., vacant lots), unpaved 
roads, and paved roads. 62 FR 31031. As can be seen from Table 9, the 
emission reductions from the proposed FIP rule for unpaved roads and 
vacant lots are sufficient to assure incremental emission reductions 
between 1998 and 2001 at the West Chandler monitoring sites; therefore, 
EPA proposes to determine that the FIP assures RFP for the 24-hour 
standard at the West Chandler monitor.

               Table 9.--RFP Demonstration for the 24-hour Standard--West Chandler Monitoring Site              
----------------------------------------------------------------------------------------------------------------
                                                                              1998                       2001   
                             Source category                               Emissions    FIP control   Emissions 
                                                                            (kg/day)     (percent)     (kg/day) 
----------------------------------------------------------------------------------------------------------------
Agriculture.............................................................        19378          0           19378
Vacant lots.............................................................         6188          0.56         2723
Road Construction.......................................................          440          0             440
Agricultural apron......................................................         1954          0            1954
Unpaved road............................................................           49          0.64           18
Paved roads.............................................................           37          0              37
                                                                         ---------------------------------------
      Total.............................................................        28046  ............        24550
----------------------------------------------------------------------------------------------------------------

VI. Impact on Indian Reservations

    The Phoenix PM-10 nonattainment area includes two Indian 
reservations (the Salt River Pima-Maricopa Indian Community and the 
Fort McDowell Mojave-Apache Indian Community) and a portion of a third 
(the Gila River Indian Community). As discussed in section II.A.4. 
above, EPA's obligation is to apply the measures in the proposed FIP to 
those sources that would have been regulated under the moderate area 
PM-10 SIP. That does not include those sources located within Indian 
country that are not subject to State jurisdiction, and the State of 
Arizona has not demonstrated to EPA it has any such jurisdiction with 
respect to these lands.
---------------------------------------------------------------------------

    \38\The microscale analysis at each monitor evaluated sources in 
a very limited geographic area. Because of this limited area, there 
is little opportunity for sources to expand. In some cases, a source 
that was present at the microscale site in 1995 no longer exists 
(e.g., the freeway construction at the West Chandler site); however, 
for this demonstration, EPA has assumed that the source is still 
present since the sites were chosen to be representative of other 
sites in the nonattainment area.
---------------------------------------------------------------------------

    In addition, EPA believes it would be inappropriate to apply 
federal control measures to Indian country sources without data showing 
that these sources are contributing to the area's nonattainment 
problem. No such data has been submitted to EPA. Therefore, EPA 
proposes to exclude sources located in Indian country from the proposed 
FIP requirements.
    However, EPA believes that the solution to the Phoenix PM-10 
problem must be developed in an equitable manner, and recognizes that 
such a solution may require that emission controls be applied to 
certain on-reservation PM-10 sources. In order to assess whether 
controls should be applied in Indian country, it will be necessary to 
obtain enough data to identify on-reservation sources and assess their 
contribution to the air quality problem. EPA is committed to working 
closely with the Indian tribes to identify impacts of activities on the 
reservations on the nonattainment area, and to ensure, if necessary, 
that on-reservation emissions are controlled in

[[Page 15942]]

a manner consistent with attainment of the NAAQS.
    The three Phoenix-area tribal governments have indicated their 
willingness to take appropriate steps to protect and improve air 
quality in the Phoenix area. All three tribes have been building 
environmental regulatory programs for several years, and all three have 
expressed their intention to add an air quality component to these 
programs. The Gila River Indian Community and the Salt River Pima-
Maricopa Indian Community are actively developing CAA programs with 
grant support from EPA Region IX. The Fort McDowell Indian Community is 
working with EPA Region IX to develop an air grant project that will 
result in the development of an air quality needs assessment for the 
Tribe. For all three tribes, an early step in the program development 
process will be to generate detailed emissions inventory data and 
assess the need for regulations to control emissions from on-
reservation sources.
    It took many years for states to develop the comprehensive air 
quality programs that exist now; likewise, air quality program 
development can be expected to take many years for tribes. EPA is 
committed to working closely with the three Phoenix-area tribes over 
the next several years to enhance and support their air program 
development. EPA will provide the necessary technical and financial 
support to ensure not only that an adequate level of data is generated 
in order to assess appropriate air pollution controls for the 
reservations, but also to ensure that the tribes develop the capacity, 
if they so desire, to implement such controls through tribal CAA 
programs. As a backstop, and consistent with 40 CFR section 49.11(a), 
EPA is prepared to develop federal measures to implement PM-10 controls 
necessary to attain the NAAQS in the absence of an approved tribal CAA 
program.
    Furthermore, EPA recognizes that there is a potential equity issue 
regarding nonattainment area agricultural activities as addressed by 
this proposal, specifically that many of the farms on the Indian 
reservations are leased to commercial farmers who are also actively 
farming off-reservation. In order to address this issue, EPA will 
actively support tribal participation in the process of developing the 
agricultural BMPs described in section V.A.7.a. above, and will promote 
the equitable implementation of BMPs throughout the Phoenix 
nonattainment area.

VII. Administrative Requirements

A. Executive Order (E.O.) 12866

    Under Executive Order 12866, 58 FR 51735 (October 4, 1993), the 
Agency must determine whether the regulatory action is ``significant'' 
and therefore subject to Office of Management and Budget (OMB) review 
and the requirements of the Executive Order. The Order defines 
``significant regulatory action'' as one that is likely to result in a 
rule that may:

    (1) Have an annual effect on the economy of $100 million or more 
or adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with 
an action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, 
grants, user fees, or loan programs or the rights and obligations of 
recipients thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.

    Due to potential novel policy issues this action is considered a 
significant regulatory action and therefore must be reviewed by OMB. 
Changes made in response to OMB suggestions or recommendations will be 
documented in the public record.

B. Regulatory Flexibility Analysis

1. Regulatory Flexibility Act Requirements
    Under the Regulatory Flexibility Act (RFA), 5 U.S.C. section 601 
et. seq., EPA must prepare a regulatory flexibility analysis assessing 
the impact of any proposed or final rule on small entities unless EPA 
certifies that the rule will not have a significant economic impact on 
a substantial number of small entities. 5 U.S.C. sections 603, 604 and 
605(b). Small entities include small businesses, small not-for-profit 
enterprises, and government entities with jurisdiction over populations 
of less than 50,000.
    For the purposes of this inquiry, as it applies to the two proposed 
federal measures, the fugitive dust rule and the commitment for the 
development and implementation of RACM for the agricultural sector, EPA 
is assuming that the affected or potentially affected sources 
constitute ``small entities'' as defined by the RFA.
    The proposed federal measures are intended to fill gaps in the 
Arizona PM-10 SIP for the Phoenix nonattainment area. For non-
agricultural fugitive dust sources, while the County has adopted and 
EPA has approved Rule 310 into the SIP, the County has not made a 
commitment to provide adequate resources to ensure enforcement of the 
rule as it applies to the unpaved road, unpaved parking lot and vacant 
lot source categories.39 Further, application of Rule 310 to 
agricultural sources including fields and aprons is affected by the 
provision in section 102 (incorporating A.R.S. 49-504.4) that states 
that the rule ``shall not be construed so as to prevent normal farm 
cultural practices.'' Therefore, applicability of the rule to such 
sources depends on what dust-generating operation is occurring at the 
source. In other words, Rule 310 applies to some operations on 
agricultural fields and aprons and not to others.
---------------------------------------------------------------------------

    \39\The County typically only ensures compliance with Rule 310 
for these sources on a complaint basis.
---------------------------------------------------------------------------

2. RFA Analysis
    a. Proposed Federal Rule for Unpaved Roads, Unpaved Parking Lots, 
and Vacant Lots. The starting point for EPA's analysis is Maricopa 
County's Rule 310. Regardless of the County's resources for enforcing 
the rule with respect to nonagricultural fugitive dust sources, those 
sources are legally responsible for complying with it. Failure to do so 
subjects such sources to potential enforcement action by EPA, the 
State, County and/or citizens. Thus, for the purpose of analyzing 
whether the proposed FIP rule will have ``a significant economic 
impact,'' EPA assumes that sources subject to the rule are complying 
with it. The appropriate inquiry then is whether the terms of EPA's 
proposed rule would impose a significant economic impact beyond that 
imposed by the terms of Rule 310.
    Section 101 of Rule 310 states that the purpose of the rule is 
``[t]o limit the emission of particulate matter into the ambient air 
from any property, operation or activity that may serve as an open 
fugitive dust source.'' Further, the provisions of the rule ``apply to 
any activity, equipment, operation and/or man-made or man-caused 
condition or practice * * * capable of generating fugitive dust. * * 
*'' Sections 305, 306, 309 and 312 of the rule contain the regulatory 
requirements applicable to the following source categories: vehicle use 
in open areas and vacant parcels, unpaved parking areas, vacant areas, 
and roadways. These requirements differ to some extent depending on the 
source category, but generally they mandate the implementation of RACM 
before certain dust-producing activities

[[Page 15943]]

can be undertaken. RACM is defined in section 221 as ``[a] technique, 
practice, or procedure used to prevent or minimize the generation, 
emission, entrainment, suspension and/or airbourne transport of 
fugitive dust.'' As further defined in subsection 221.1, and as 
pertinent to this analysis, RACM include, but are not limited to: 
curbing, paving, applying dust suppressants, and/or physically 
stabilizing with vegetation and gravel.
    While subsection 211.1 does not specify which of the listed 
measures are appropriate for what types of source categories, the 
general definition of RACM in section 221 together with the list of 
RACM measures in subsection 211.1 provide a basis for selecting 
measures which are appropriate for a particular source to prevent or 
minimize dust emissions, to the extent other provisions of Rule 310 do 
not specify a particular RACM measure.
    EPA's proposed fugitive dust rule is intended to establish a RACM 
requirement for unpaved parking lots, unpaved roads and vacant lots 
that is substantively equivalent to that established for the same 
sources by the Maricopa County rule. As noted above, the requirements 
of the County rule differ to some extent depending on the source 
category; EPA's proposed rule mirrors those differences. The primary 
difference between the County rule and EPA's proposed rule is that the 
EPA rule provides greater specificity and detail regarding which RACM 
are appropriate for a particular source category for the purpose of 
preventing or minimizing fugitive dust emissions.40
---------------------------------------------------------------------------

    \40\EPA believes that it is reasonable and appropriate for its 
proposed rule to be more specific and detailed than the County rule. 
As a result of the State's failure to commit sufficient enforcement 
resources for its rule, EPA is having to fulfill the role of primary 
enforcer of the RACM requirement for the sources described above. 
EPA Region 9 will be responsible for fulfilling that role, and it is 
located in San Francisco. Given the greater difficulties that Region 
9 will inevitably face in enforcing the RACM requirement in Arizona, 
it is reasonable for EPA to design a RACM rule that ensures EPA 
enforcement of the rule will be practicable. As described above, the 
County rule provides a general basis for determining which RACM 
should be applied to which source categories. But its lack of 
specificity makes it more likely that the agency enforcing the rule 
will routinely be called upon to address which RACM should be 
applied to which source categories. By addressing this issue in the 
FIP rule itself, EPA hopes to reduce the extent to which sources and 
others may have to consult with the Agency to determine which RACM 
are appropriate for a particular source or source category.
---------------------------------------------------------------------------

    In providing further specificity and detail, EPA's proposed rule 
does not change the nature of the RACM requirement already applicable 
to sources covered by County Rule 310. The RACM required to be applied 
in the proposed FIP rule are the very measures listed in subsection 
211.1 of Rule 310. Beyond that, the RACM specified in the proposed rule 
for any particular source category are the appropriate RACM for that 
source category. What constitutes RACM for the source categories 
covered by the proposed FIP rule is relatively straightforward in light 
of the differences among the source categories, the low technology 
nature of the potential RACM and other available information. EPA 
therefore believes that its further specification of the RACM 
requirements does not change the nature of the RACM requirements 
already applicable under County Rule 310.
    The only other notable difference between the County rule and the 
proposed FIP rule that is relevant to this analysis is section 600 of 
the proposed FIP rule. Rule 310 contains a recordkeeping requirement 
for permitted dust-generating activities, but does not contain such a 
requirement for unpermitted activities, including unpaved parking lots, 
unpaved roads and vacant lots. Therefore, section 600 of the proposed 
FIP rule includes a requirement that owners/operators subject to the 
rule maintain records demonstrating appropriate application of RACM. 
EPA has determined that the recordkeeping requirements for the source 
categories covered in the FIP rule will not have a significant economic 
impact. In many cases, the owner/operator need only retain a purchase 
receipt or contractor work order for the control(s) implemented. When 
chemical stabilization is applied as a control measure, more specific 
information regarding the product being used is required. However, this 
information (e.g., type of product, label instructions) is readily 
available from vendors or easily determined at the time of application. 
EPA expects that the information the proposed rule would require 
sources to keep would be retained by source owners or operators in any 
event in the normal course of business (e.g., for tax and accounting 
purposes).
    As the above discussion of the RACM requirements of the two rules 
makes clear, even though the proposed FIP rule differs from Rule 310 in 
that it is more specific and detailed, there should be no additional 
burden on regulated sources because they are already legally required 
to apply RACM under the County rule, and the RACM required by the 
proposed FIP rule is substantively identical to that required under 
Rule 310. Moreover, EPA believes that the additional recordkeeping 
requirement in the proposed FIP rule will not have a significant 
economic impact on the affected sources. As stated above and in section 
V.A.7.b., the information proposed to be retained is minimal and is 
therefore not expected to entail any appreciable economic impact.
    b. Proposed Federal Commitment for Agriculture. EPA's proposed 
measure to control fugitive dust from agricultural fields and aprons 
consists of an enforceable commitment to propose and finalize adoption 
of RACM for those sources in September 1999 and April 2000, 
respectively. Prior to this formal rulemaking, EPA intends to convene a 
stakeholder process to develop the specific RACM that will ultimately 
be proposed for adoption. As discussed in detail in section V.A.7.a. 
above, EPA's intends the RACM to take the form of BMPs. During the BMP 
development process, EPA will investigate a myriad of factors, 
including the appropriate coverage of potential BMPs, regional climate, 
soil and crop types, and growing seasons.
    Because this aspect of today's action neither proposes specific 
regulatory requirements, nor obligates EPA to propose requirements 
necessarily applicable to small entities, it will not, by itself, have 
a significant economic impact on a substantial number of small 
entities. When EPA proposes specific RACM in the September 1999 
rulemaking, it will either undertake a RFA analysis or certify the 
proposed rule, as appropriate.
    c. Certification. For the reasons set forth above, pursuant to 5 
U.S.C. 605(b), EPA certifies that today's proposed federal rules do not 
have a significant impact on a substantial number of small entities 
within the meaning of those terms for RFA purposes.

C. Unfunded Mandates Reform Act (UMRA)

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L. 
104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector.
    Under section 202 of the UMRA, EPA generally must prepare a written 
statement, including a cost-benefit analysis, when EPA promulgates 
``any general notice of proposed rulemaking that is likely to result in 
promulgation of any rule that includes any Federal mandate that may 
result in the expenditures by State, local, and tribal governments, in 
the aggregate, or by the private sector, of $100 million or more'' in 
any one year. A ``Federal mandate'' is defined, under section 101 of 
UMRA, as a provision that ``would impose an enforceable duty'' upon the 
private

[[Page 15944]]

sector or State, local, or tribal governments'', with certain 
exceptions not here relevant.
    Under section 203 of UMRA, EPA must develop a small government 
agency plan before EPA ``establish[es] any regulatory requirements that 
might significantly or uniquely affect small governments''.
    Under section 204 of UMRA, EPA is required to develop a process to 
facilitate input by elected officers of State, local, and tribal 
governments for EPA's ``regulatory proposals'' that contain significant 
Federal intergovernmental mandates.
    Under section 205 of UMRA, before EPA promulgates ``any rule for 
which a written statement is required under [UMRA section] 202'', EPA 
must identify and consider a reasonable number of regulatory 
alternatives and either adopt the least costly, most cost-effective or 
least burdensome alternative that achieves the objectives of the rule, 
or explain why a different alternative was selected.
    As explained above, while the proposed federal fugitive dust rule 
may impose an enforceable duty on State or local governments, the 
resulting expenditures by those entities are expected to be minimal. 
Tribal governments are excluded from the coverage of this proposed 
rule. In addition, there will be no current enforceable duties imposed 
on, or expenditures by, State, local or tribal governments or the 
private sector as a result of the proposed federal commitment regarding 
the agricultural sector. Therefore, expenditures by State, local and 
tribal governments, in the aggregate, or by the private sector, will be 
well under $100 million per year as a result of today's proposed 
federal measures. Consequently, sections 202, 204 and 205 of UMRA do 
not apply to today's proposed action. Therefore, EPA is not required 
and has not taken any actions to meet the requirements of these 
sections of UMRA.
    With respect to section 203 of UMRA, EPA has concluded that its 
proposed actions include no regulatory requirements that will 
significantly or uniquely affect small governments. As discussed in 
detail in section VII.B. above, EPA believes that the RACM requirements 
of the proposed FIP rule for vacant lots, unpaved parking lots and 
unpaved roads are already legally required under Maricopa County Rule 
310. Moreover, the requirements of EPA's proposed FIP rule, while more 
specific and detailed, are substantively identical to those required 
under Rule 310. Therefore, there should be no additional burden on 
regulated sources, including small governments. With respect to EPA's 
proposed enforceable commitment for the agricultural sector, such a 
commitment neither proposes specific regulatory requirements, nor 
obligates EPA to propose requirements necessarily applicable to small 
entities. Thus, neither EPA's proposed fugitive dust rule nor its 
proposed commitment for the agricultural sector will significantly or 
uniquely affect small governments. Consequently, EPA has not developed 
a small government plan. Nevertheless, during the development of 
today's proposed action, EPA held numerous meetings with potentially 
affected representatives of the State and local governments to discuss 
the requirements of, and receive input regarding, the proposed federal 
fugitive dust rule and commitment for the agricultural sector.

D. Paperwork Reduction Act

    The information collection requirements in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An 
Information Collection Request (ICR) document has been prepared by EPA 
(ICR No. 1855.01) and a copy may be obtained from Sandy Farmer, OPPE 
Regulatory Information Division; U.S. Environmental Protection Agency 
(2137); 401 M St., S.W.; Washington, DC 20460 or by calling (202) 260-
2740.
    EPA's proposed FIP rule for unpaved parking lots, unpaved roads and 
vacant lots includes recordkeeping and reporting requirements which 
will help ensure source compliance with the rule's control 
requirements. In general, EPA believes the recordkeeping and reporting 
requirements are the minimal requirements necessary to demonstrate 
compliance. The requirents include:

--Owners/operators of unpaved roads must keep a record which 
indicates the date and type of control (i.e., paving, stabilizing, 
or applying gravel) applied to the road.
--Owners/operators of unpaved parking lots must keep a record which 
indicates the date and type of control (i.e., paving, stabilizing, 
applying gravel, or temporary stabilization for lots used less than 
35 days per year) applied to the unpaved parking lot.
--Responsible party(ies) for unpermitted weed abatement activities 
on vacant lots must develop a dust control plan and submit the plan 
to EPA for approval prior to the weed abatement.
--Owners/operators of vacant lots with disturbed surfaces must keep 
a record which indicates the date and type of control (i.e., 
applying ground cover vegetation, stabilizing, restoring to natural 
undisturbed state, or applying gravel) applied to the vacant lot.
--Owners/operators of vacant lots with motor vehicle disturbances 
must keep a record which indicates the date and type of control 
(i.e., installing signs, fences, dust suppressants, or cement 
barriers) applied to the vacant lot.
--Agency surveys will be conducted by the EPA or other appropriate 
agency to determine the effectiveness of the rule in the Phoenix 
area.

    The estimated recordkeeping and reporting burden for the proposed 
FIP rule is about 9716 hours. The estimated labor cost is about 
$173,632. No capital/start-up costs or operational and maintenance 
costs are anticipated. Burden means the total time, effort, or 
financial resources expended by persons to generate, maintain, retain, 
or disclose or provide information to or for a Federal agency. This 
includes the time needed to review instructions; develop, acquire, 
install, and utilize technology and systems for the purposes of 
collecting, validating, and verifying information, processing and 
maintaining information, and disclosing and providing information; 
adjust the existing ways to comply with any previously applicable 
instructions and requirements; train personnel to be able to respond to 
a collection of information; search data sources; complete and review 
the collection of information; and transmit or otherwise disclose the 
information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control number for EPA's 
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
    Comments are requested on the Agency's need for this information, 
the accuracy of the provided burden estimates, and any suggested 
methods for minimizing respondent burden, including through the use of 
automated collection techniques. Send comments on the ICR to the 
Director, OPPE Regulatory Information Division; U.S. Environmental 
Protection Agency (2137); 401 M St., S.W.; Washington, DC 20460; and to 
the Office of Information and Regulatory Affairs, Office of Management 
and Budget, 725 17th St., N.W. Washington, DC 20503, marked 
``Attention: Desk Officer for EPA.'' Include the ICR number in any 
correspondence. Since OMB is required to make a decision concerning the 
ICR between 30 and 60 days after April 1, 1998, a comment to OMB is 
best assured of having its full effect if OMB receives it by May 1, 
1998. The final rule will respond to any OMB or public

[[Page 15945]]

comments on the information collection requirements contained in this 
proposal.

List of Subjects in 40 CFR Part 52

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

    Dated: March 20, 1998.
Carol M. Browner,
Administrator.

    For the reasons set forth in the preamble, part 52, chapter I, 
title 40 of the Code of Federal Regulations is proposed to be amended 
as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart D--Arizona

    2. Subpart D is proposed to be amended by adding Secs. 52.127 and 
52.128 to read as follows:


Sec. 52.127  Commitment to promulgate and implement reasonably 
available control measures for the agricultural fields and aprons.

    The Administrator shall promulgate and implement reasonably 
available control measures (RACM) pursuant to section 189(a)(1)(C) of 
the Clean Air Act for agricultural fields and aprons in the Maricopa 
County (Phoenix) PM-10 nonattainment area according to the following 
schedule: by no later than September, 1999, the Administrator shall 
sign a Notice of Proposed Rulemaking; by no later than April, 2000, the 
Administrator shall sign a Notice of Final Rulemaking; and by no later 
than June, 2000, EPA shall begin implementing the final RACM.


Sec. 52.128  Rule for unpaved parking lots, unpaved roads and vacant 
lots.

    (a) General.--(1) Purpose. The purpose of this section is to limit 
the emissions of particulate matter into the ambient air from human 
activity on unpaved parking lots, unpaved roads and vacant lots.
    (2) Applicability. The provisions of this section shall apply to 
owners/operators of unpaved roads, unpaved parking lots and vacant lots 
and responsible parties for weed abatement on vacant lots in the 
Phoenix PM-10 nonattainment area. This section does not apply to 
unpaved roads, unpaved parking lots, or vacant lots located on an 
industrial facility, construction, or earth-moving site that has an 
approved permit issued by Maricopa County Environmental Services 
Division under Rule 200, Section 305 containing a Dust Control Plan 
(DCP) approved under Rule 310 covering all unpaved parking lots, 
unpaved roads and vacant lots. Nothing in this definition shall 
preclude applicability of this section to vacant lots with disturbed 
surface areas due to construction, earth-moving, weed abatement or 
other dust generating operations which have been terminated for over 
eight months.
    (b) Definitions.--(1) Average Daily Trips (ADT). The average number 
of vehicles that cross a given surface during a specified 24-hour time 
period as determined by the Institute of Transportation Engineers Trip 
Generation Report (6th edition, 1997) or tube counts.
    (2) Chemical Stabilizer. Any non-toxic chemical dust suppressant 
which meets any specifications, criteria, or tests required by any 
federal, state, or local water agency and is not prohibited for use by 
the U.S. Environmental Protection Agency or any applicable law, rule or 
regulation.
    (3) Disturbed Surface Area. Any portion of the earth's surface, or 
materials placed thereon, which has been physically moved, uncovered, 
destabilized, or otherwise modified from its undisturbed natural 
condition, thereby increasing the potential for emission of fugitive 
dust.
    (4) Dust Suppressants. Water, hygroscopic materials, solution of 
water and chemical surfactant, foam, or non-toxic chemical stabilizers 
not prohibited for use by the U.S. Environmental Protection Agency or 
any applicable law, rule or regulation, as a treatment material to 
reduce fugitive dust emissions.
    (5) EPA. United States Environmental Protection Agency, Region IX, 
75 Hawthorne Street, San Francisco, California 94105.
    (6) Fugitive Dust. The particulate matter entrained in the ambient 
air which is caused from man-made and natural activities such as, but 
not limited to, movement of soil, vehicles, equipment, blasting, and 
wind. This excludes particulate matter emitted directly from the 
exhaust of motor vehicles and other internal combustion engines, from 
portable brazing, soldering, or welding equipment, and from 
piledrivers.
    (7) Lot. A parcel of land identified on a final or parcel map 
recorded in the office of the Maricopa County recorder with a separate 
and distinct number or letter.
    (8) Motor Vehicle. A self-propelled vehicle for use on the public 
roads and highways of the State of Arizona and required to be 
registered under the Arizona State Uniform Motor Vehicle Act, including 
any non-motorized attachments, such as, but not limited to, trailers or 
other conveyances which are connected to or propelled by the actual 
motorized portion of the vehicle.
    (9) Off-Road Motor Vehicle. Any wheeled vehicle which is used off 
paved roadways and includes but is not limited to the following: any 
motor cycle or motor-driven cycle; any motor vehicle commonly referred 
to as a sand buggy, dune buggy, or all terrain vehicle.
    (10) Owner/Operator. Any person who owns, leases, operates, 
controls or supervises a fugitive dust source subject to the 
requirements of this section.
    (11) Paving. Applying asphalt, recycled asphalt, concrete, or 
asphaltic concrete to a roadway surface.
    (12) Phoenix PM-10 Nonattainment Area. Such area as defined in 40 
CFR 81.303.
    (13) PM-10. Particulate matter with an aerodynamic diameter less 
than or equal to a nominal 10 micrometers as measured by reference or 
equivalent methods that meet the requirements specified for PM-10 in 40 
CFR part 50, appendix J.
    (14) Reasonably Available Control Measures (RACM). Techniques used 
to prevent the emission and/or airborne transport of fugitive dust and 
dirt.
    (15) Stabilized Surface. (i) Any unpaved road or unpaved parking 
lot surface in which any fugitive dust plume emanating from vehicular 
movement does not exceed 20 percent opacity as determined by test 
methods in paragraph (g)(1) of this section.
    (ii) Any vacant lot surface that has a visible crust as determined 
by the test method in paragraph (g)(2)(i) of this section;
    (iii) Any vacant lot surface that is sufficiently vegetated as 
determined by test methods in paragraph (g)(2)(ii) or (g)(2)(iv) of 
this section.
    (iv) Any vacant lot surface which is stabilized as determined by 
the test method in paragraph (g)(2)(iii) of this section;
    (16) Unpaved Parking Lot. A privately or publicly owned or operated 
area utilized for parking vehicles that is not covered by concrete, 
asphaltic concrete, asphalt, or recycled asphalt.
    (17) Unpaved Road. Any road, equipment path, or driveway that is 
not covered by asphalt, asphaltic concrete, recycled asphalt, or 
concrete. Public unpaved roads are those open to public access that are 
owned by any federal, state, county, municipal or other

[[Page 15946]]

governmental or quasi-governmental agencies.
    (18) Urban or Suburban Open Area. An unsubdivided or undeveloped 
tract of land adjoining a residential, industrial, or commercial area, 
located on public or private property.
    (19) Vacant Lot. A subdivided residential, industrial, 
institutional, governmental, or commercial lot which contains no 
approved or permitted buildings or structures of a temporary or 
permanent nature.
    (c) Exemptions. The requirements in paragraph (d) of this section 
do not apply to the following:
    (1) Any unpaved parking lot 5,000 square feet or less.
    (2) Any vacant lot with less than 0.10 acres (4,356 square feet) of 
disturbed surface area(s).
    (3) Non-routine or emergency maintenance of flood control channels 
and water retention basins.
    (4) Vehicle test and development facilities and operations when 
dust is required to test and validate design integrity, product quality 
and/or commercial acceptance. Such facilities and operations shall be 
exempted from the provisions of this section only if such testing is 
not feasible within enclosed facilities.
    (5) Weed abatement operations performed on any vacant lot or 
property under the order of a governing agency for the control of a 
potential fire hazard or otherwise unhealthy condition provided that 
mowing, cutting, or other similar process is used to maintain weed 
stubble at least three (3) inches above the soil surface. This includes 
the application of herbicides provided that the clean-up of any debris 
does not disturb the soil surface.
    (6) Weed abatement operations that receive an approved Earth Moving 
permit under Maricopa County Rule 200, Section 305 (adopted 11/15/93).
    (d) Requirements.--(1) Unpaved parking lots. Any owners/operators 
of an unpaved parking lot shall implement one of the following RACM on 
the entire surface area of the lot within eight (8) months following 
[the effective date of the final rule].
    (i) An owner or operator of an unpaved parking lot shall:
    (A) Pave the lot; or
    (B) Apply chemical stabilizers in sufficient concentration and 
frequency to maintain a stabilized surface; or
    (C) Apply and maintain surface gravel uniformly to a depth of at 
least 2 inches such that the surface is stabilized.
    (ii) Any owners/operators of an unpaved parking lot that is used no 
more than 35 days per year may substitute the following control measure 
for those listed in paragraph (d)(1)(i) of this section:
    (A) Apply chemical stabilizers within 20 days prior to any day in 
which over 100 vehicles are parked. Chemical stabilizers must be 
applied in sufficient concentration and frequency to maintain a 
stabilized surface throughout any day(s) when over 100 vehicles ingress 
into the lot.
    (2) Unpaved roads. Any owners/operators of existing public unpaved 
roads with ADT volumes of 150 vehicles or greater, where at least 70% 
of the road is located within the Phoenix PM-10 nonattainment area, 
shall implement one of the following RACM along the entire surface of 
the road by June 10, 2000:
    (i) Pave the road; or
    (ii) Apply chemical stabilizers in sufficient concentration and 
frequency to maintain a stabilized surface; or
    (iii) Apply and maintain surface gravel uniformly to a depth of at 
least 2 inches such that the surface is stabilized.
    (3) Vacant lots. The following provisions shall be implemented as 
applicable:
    (i) Weed abatement. No person shall remove vegetation from any 
vacant lot by blading, disking, plowing under or any other means that 
disturbs 0.10 acres or more of soil surface without first obtaining EPA 
approval of a DCP pursuant to paragraph (d)(3)(i)(A) of this section to 
effectively prevent or minimize fugitive dust.
    (A) A DCP, containing the information described in paragraph (e)(3) 
of this section, shall be submitted to EPA at least 60 calendar days 
before the weed abatement occurs. Within 30 calendar days of its 
receipt, EPA shall provide written notice to the responsible party(ies) 
approving or disapproving the DCP. Should a DCP be disapproved, within 
14 calendar days following receipt of any revisions provided by the 
responsible party(ies) to EPA, EPA shall provide notice to the 
responsible party(ies) approving or disapproving the DCP. Should EPA 
not provide written notice of approval or disapproval within the above 
deadlines, the responsible party(ies) may assume that the DCP is 
approved.
    (B) Any person responsible for more than one weed abatement 
operation at non-contiguous sites may submit one DCP covering multiple 
sites provided that the contents of the DCP apply similarly to all such 
sites and any information specific to the site that is required by 
paragraph (e)(3) of this section is included.
    (ii) Disturbed surfaces. Any owners/operators of an urban or 
suburban open area vacant lot which remains unoccupied, unused, vacant 
or undeveloped for more than fifteen (15) days of which any portion has 
a disturbed surface area(s) shall implement one of the following RACM 
within eight (8) months following [the effective date of the final 
rule] or within eight (8) months following the initial fifteen-day 
period of inactivity, whichever is later:
    (A) Establish ground cover vegetation on all disturbed surface 
areas in sufficient quantity to maintain a stabilized surface; or
    (B) Apply dust suppressants to all disturbed surface areas in 
sufficient quantity and frequency to maintain a stabilized surface; or
    (C) Restore to a natural state, i.e. as existing in or produced by 
nature without cultivation or artificial influence, such that all 
disturbed surface areas are stabilized; or
    (D) Apply and maintain surface gravel uniformly over all disturbed 
surface areas to a depth of at least 2 inches such that all disturbed 
surface areas are stabilized.
    (iii) Motor Vehicle Disturbances. Any owners/operators of an urban 
or suburban open area vacant lot of which any portion has a disturbed 
surface area due to motor vehicle or off-road motor vehicle use or 
parking, notwithstanding use or parking by the owner(s), one of the 
following RACM shall be implemented within 60 calendar days following 
the initial determination of disturbance:
    (A) Place signs at intervals of at least 300 feet, as measured 
along the access perimeter, that state ``Dust Control Area: No 
Trespassing'' with lettering at least two inches in height; or
    (B) Place fencing along the access perimeter; or
    (C) Plant shrubs or trees at least two (2) feet in height that 
prohibit motor vehicle and off-road motor vehicle entry along the 
access perimeter; or
    (D) Place cement barriers that prohibit motor vehicle and off-road 
motor vehicle entry along the access perimeter.
    (4) Alternative control measures. For sources subject to 
requirements in paragraphs (d)(1), (d)(2), (d)(3)(ii) and (d)(3)(iii) 
of this section: As an alternative to compliance, owners/operators may 
use any other alternative control measures approved by EPA pursuant to 
paragraphs (e)(1) and (e)(2) of this section as equivalent to the 
methods specified in paragraph (d) of this section.
    (e) Administrative requirements. (1) Proposed alternative control 
measures for sources subject to paragraph (d)(1) of this section must 
be submitted to EPA

[[Page 15947]]

for approval within one year of the effective date of the final rule. 
Proposed alternative control measures for sources subject to paragraphs 
(d)(2) and (d)(3)(ii) of this section must be submitted to EPA for 
approval within 90 days prior to the required RACM implementation date 
as specified in this section. Proposed alternative control measures for 
sources subject to paragraph (d)(3)(iii) of this section must be 
submitted to EPA for approval within 60 calendar days following the 
initial determination of disturbance.
    (2) Upon receipt of an alternative control measure, EPA shall 
provide written notice within 30 calendar days to the owner/operator 
approving or disapproving the alternative control measure. Should EPA 
not provide written notice of approval or disapproval within the above 
deadline, the owner/operator shall assume that the alternative control 
measure is approved. Upon receiving notice of EPA approval, the owner/
operator shall implement the alternative control measure according to 
the timeframe established in this section unless otherwise specified by 
EPA. Upon receiving notice of EPA disapproval of the alternative 
control measure, the owner/operator shall implement RACM according to 
the specifications and timeframe established in this section. For 
sources submitting an alternative control measure under paragraph 
(d)(3)(iii) of this section, owners/operators shall implement the 
alternative control measure if approved by EPA within 60 days upon 
receiving written notice, or, upon disapproval of the alternative 
control measure, implement RACM as specified in this section within 60 
days upon receiving written notice.
    (3) Information to be included in a DCP:
    (i) Name(s), address(es) and phone number(s) of person(s) 
responsible for the preparation, submittal and implementation of the 
DCP and responsible for the weed abatement operation(s).
    (ii) A plot plan of the site which describes:
    (A) The location of the site;
    (B) The total area of land surface subject to disturbance and the 
total area of the entire project site, in acres;
    (C) The type of weed abatement operation(s) and equipment to be 
used on the site.
    (iii) A description of:
    (A) Dust control measures or combinations thereof to be applied 
during all periods of weed abatement operations, including post-weed 
abatement and any operations conducted afterwork hours and on weekends 
and holidays, to all surface areas subject to disturbance as described 
in the plot plan.
    (B) Dust control measures to be applied on all days when wind 
speeds exceed 25 miles per hour.
    (C) Dust suppressant(s) to be applied, including product 
specifications or label instructions for approved usage; the method, 
frequency and concentration of application; the type, number and 
capacity of application equipment and; information on environmental 
impacts and approvals or certifications related to appropriate and safe 
use for ground applications.
    (D) The specific surface treatment(s) and/or control measures 
utilized to control material track-out and sedimentation onto unpaved 
surfaces and access points adjoining paved surfaces.
    (f) Monitoring and records (1) Any owners/operators that are 
subject to the provisions of this section shall compile and retain 
records that provide evidence of control measure application, 
indicating the type of treatment or measure, extent of coverage and 
date applied. For control measures involving chemical stabilization, 
records shall also indicate the type of product applied, vendor name, 
label instructions for approved usage, and the method, frequency and 
concentration of application.
    (2) Copies of control measure records and dust control plans along 
with supporting documentation shall be retained for at least three 
years.
    (3) Agency surveys. (i) EPA or other appropriate entity shall 
conduct a survey of the number and size (or length) of unpaved roads, 
unpaved parking lots, and vacant lots subject to the provisions of this 
section located within the Phoenix PM-10 nonattainment area beginning 
no later than 365 days following [the effective date of the final 
rule].
    (ii) EPA or other appropriate entity shall conduct a survey at 
least every three years within the Phoenix PM-10 nonattainment area 
beginning no later than 365 days following [the effective date of the 
final rule] which includes:
    (A) An estimate of the percentage of unpaved roads, unpaved parking 
lots, and vacant lots subject to this section to which RACM as required 
in this section have been applied; and
    (B) A description of the most frequently applied RACM and estimates 
of their control effectiveness.
    (g) Test methods. (1) For determining whether unpaved roads and 
unpaved parking lots are stabilized, visible opacity from vehicular 
movement shall not exceed twenty (20) percent. Opacity observations 
shall be conducted in accordance with Reference Method 9 (40 CFR part 
60, appendix A), [Proposed Methods 203A, 203B, and 203C, with opacity 
readings conducted according to Method 203C]\1\. Visible opacity tests 
shall only be conducted on dry unpaved surfaces (i.e. when the surface 
is not damp to the touch) and on days when average wind speeds do not 
exceed 15 miles per hour (mph). For purposes of this section, visible 
opacity tests shall be conducted using the following vehicle speeds: 35 
mph on unpaved roads and 20 mph on unpaved parking lots.
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    \1\These proposed methods in 40 CFR part 51, appendix M, were 
published at 58 FR 61640, November 22, 1993.
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    (2) The test methods in this paragraph (g)(2) shall be used for 
determining whether a vacant lot, or portion thereof, has a stabilized 
surface. Evidence of disturbance is loss of vegetation cover and 
disintegration of surface compaction and/or crusts. The surface shall 
be considered stabilized if any of the following test methods indicate 
that conditions defining a stabilized surface have been met:
    (i)(A) Where a visible crust exists which is greater than 0.6 cm 
thick and not easily crumbled between the fingers, the surface shall be 
considered stabilized. This determination shall be based on the 
majority of at least three (3) crustal measurements representative of 
the disturbed surface area.
    (B) If thin deposits of loose uncombined surface material cover 
more than 50 percent of a crusted surface, the test method described in 
paragraph (g)(2)(iii) of this section shall be applied to the loose 
material to determine whether the surface is stabilized.
    (ii) Where flat vegetation covers at least 50 percent of the 
disturbed surface area as determined by the line transect method 
described in ``Estimating Percent Residue Cover Using the Line-Transect 
Method'', G93-1133 (February 1997, Electronic version), Cooperative 
Extension, Institute of Agriculture and Natural Resources, University 
of Nebraska-Lincoln, the surface shall be considered stabilized. Flat 
vegetation shall include attached vegetation or unattached vegetative 
debris lying on the surface with a predominant horizontal orientation 
and a vertical height of one (1) inch or less that is not subject to 
movement by wind. Flat vegetation which is dead but firmly attached 
shall be considered equally protective as live vegetation. Stones or 
other aggregate larger than one

[[Page 15948]]

centimeter in diameter may be considered protective cover in the course 
of conducting the line transect method.
    (iii) For all other surface conditions, at least three (3) soil 
samples shall be collected representative of the disturbed surface 
area. Each sample shall be measured for threshold friction velocity in 
accordance with the sieving field procedure found in ``Industrial Wind 
Erosion'' (Fifth Edition, Volume I, Chapter 13, Section 13.2.5, 1995), 
AP-42, Office of Air Quality Planning & Standards, U.S. Environmental 
Protection Agency, Research Triangle Park, North Carolina. Corrections 
for non-erodible elements (not including flat or standing vegetation), 
shall be determined by following the procedures in ``Rapid Assessment 
of Exposure to Particulate Emissions from Surface Contamination 
Sites'', (February 1985, Appendix A) EPA/600/8-85/002, Office of Health 
and Environmental Assessment, United States Environmental Protection 
Agency, Washington DC. Non-erodible elements shall be defined as 
elements on the disturbed surface area which remain firmly in place 
during a wind episode and inhibit soil loss by consuming part of the 
shear stress of the wind, such as stones larger than one centimeter in 
diameter. Soil samples shall only be collected from dry surfaces (i.e. 
when the surface is not damp to the touch) to a depth of approximately 
one (1) centimeter. The threshold friction velocity of all soil samples 
shall be averaged. The surface shall be considered stabilized if the 
threshold friction velocity, corrected for non-erodible elements, is 
equal to or greater than 100 centimeters per second.
    (iv) Where standing vegetation is firmly attached to the disturbed 
surface area and the corrected threshold friction velocity measured in 
paragraph (g)(2)(iii) of this section is equal to or greater than 
forty-three (43) centimeters per second, the surface shall be 
considered stabilized if the average frontal silhouette area of the 
standing vegetation per unit of ground area is ten (10) percent or 
greater. Where standing vegetation is firmly attached to the disturbed 
surface area and the corrected threshold friction velocity measured in 
paragraph (g)(2)(iii) of this section is less than forty-three (43) 
centimeters per second, the surface shall be considered stabilized if 
the average frontal silhouette area of the standing vegetation per unit 
of ground area is thirty (30) percent or greater. Standing vegetation 
shall include vegetation that is attached via root systems with 
predominant vertical orientation and a height exceeding one (1) inch. 
Standing vegetation which is dead but firmly attached shall be 
considered equally protective as live vegetation.
    (A) For standing vegetation that consists of separate vegetative 
units (for example, shrubs and sagebrush), the standard unit area of 
ground surface to be surveyed shall be a square of side length equal to 
at least 10 times the average height of the vegetative structure. For 
other standing vegetation, the standard unit area to be surveyed shall 
be three (3) feet by 3 feet.
    (B) The number of standing vegetative structures within the 
standard unit area shall be counted. Vegetation which grows in clumps 
shall be counted as a single unit. Where vegetation of diverse 
dimensions is present, vegetation shall be counted separately in groups 
with similar horizontal and vertical structural dimensions. The width 
and height of the vegetation that is representative of the average 
dimensions of the general vegetation within each structural group in 
the standard unit area shall be measured and multiplied together to 
obtain a frontal silhouette area. The frontal silhouette areas for each 
vegetative group shall be multiplied by the total number of vegetation 
counted within each group and added together to arrive at the total 
frontal silhouette area of all standing vegetative structures. The 
total frontal silhouette area shall be divided by the total standard 
unit area and multiplied by 100 to arrive at the percent frontal 
silhouette area coverage.
    (C) This procedure shall be repeated for at least two additional 
representative areas within the disturbed portion(s) of the vacant lot. 
The three percent frontal silhouette areas shall be averaged. Total 
frontal silhouette areas of distinct standard unit areas may only be 
added together if the vegetation is relatively uniform and consistent 
in spacing over the entire disturbed surface area.
    (3) Alternative test methods may be used upon obtaining the written 
approval of the EPA.

[FR Doc. 98-8061 Filed 3-31-98; 8:45 am]
BILLING CODE 6560-50-P