[Federal Register Volume 59, Number 144 (Thursday, July 28, 1994)]
[Unknown Section]
[Page ]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-18334]


[Federal Register: July 28, 1994]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[AZ31-1-6531; FRL-5021-9]


Approval and Promulgation of Implementation Plans; Arizona--
Phoenix Nonattainment Area; PM10

AGENCY: U.S. Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking.

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SUMMARY: EPA today proposes to approve the State implementation plan 
(SIP) submitted by the State of Arizona for the purpose of bringing 
about the attainment in the Phoenix Planning Area (PPA) of the national 
ambient air quality standards (NAAQS) for particulate matter with an 
aerodynamic diameter less than or equal to a nominal 10 micrometers 
(PM10). The ``moderate'' area SIP was submitted by the State to 
satisfy certain Federal requirements in the Clean Air Act for an 
approvable nonattainment area PM10 plan for the PPA.
    Because the State of Arizona has demonstrated that it is 
impracticable for the area to attain the PM10 NAAQS by the 
December 31, 1994 attainment date, even with the implementation of 
reasonably available control measures, EPA has the discretion to 
reclassify the PPA from a ``moderate'' to a ``serious'' nonattainment 
area at this time. In the alternative, EPA can evaluate the attainment 
status of the area after December 31, 1994 and reclassify the area at 
that time if the data warrant. While EPA is proposing in this notice to 
reclassify the PPA at this time, it is the Agency's current position 
that evaluation of the area's attainment status after December 31, 1994 
is the more appropriate approach. EPA is requesting comment on these 
alternative approaches.

DATES: Comments on this proposed action must be received in writing by 
August 29, 1994. Comments should be addressed to the contact indicated 
below.

ADDRESSES: Copies of the State's submittal and other information are 
contained in the docket for this rulemaking. The docket is available 
for inspection during normal business hours at the following location: 
U. S. Environmental Protection Agency, Region 9, 75 Hawthorne Street, 
San Francisco, CA 94105.

FOR FURTHER INFORMATION CONTACT: Robert S. Pallarino (A-2-2), U. S. 
Environmental Protection Agency, Region 9, Air and Toxics Division, 75 
Hawthorne Street, San Francisco, CA 94105, (415) 744-1212.
SUPPLEMENTARY INFORMATION:

I. Background

    On the date of enactment of the 1990 Clean Air Act Amendments, 
PM10 areas, including the Phoenix Planning Area (PPA), meeting the 
conditions of section 107(d) of the Act were designated nonattainment 
by operation of law. Once an area is designated nonattainment, section 
188 of the Act outlines the process for classification of the area and 
establishes the area's attainment date. In accordance with section 
188(a), at the time of designation, all PM10 nonattainment areas 
were initially classified as ``moderate'' by operation of law. See 40 
CFR 81.303 (1993) A moderate area may subsequently be reclassified as 
``serious'' if at any time EPA determines that the area cannot 
practicably attain the PM10 NAAQS by the applicable attainment 
date for moderate areas, December 31, 1994. Moreover, a moderate area 
must be reclassified if EPA determines within six months after the 
applicable attainment date that the area is not in attainment after 
that date. See section 188(b) of the Clean Air Act.
    The air quality planning requirements for moderate PM10 
nonattainment areas are set out in subparts 1 and 4 of Title I of the 
Act. EPA has issued a ``General Preamble'' 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 PM10 nonattainment area SIP provisions. See 
generally 57 FR 13498 (April 16, 1992) and 57 FR 18070 (April 28, 
1992). Because EPA is describing its interpretations here only in broad 
terms, the reader should refer to the General Preamble for a more 
detailed discussion of the interpretations of Title I advanced in 
today's proposal and the supporting rationale. In today's rulemaking 
action on Arizona's moderate PM10 SIP for the PPA, EPA is 
proposing to apply its interpretations taking into consideration the 
specific factual issues presented. EPA will consider any timely 
submitted comments before taking final action on today's proposal.
    Those states containing initial moderate PM10 nonattainment 
areas were required to submit, among other things, the following 
provisions by November 15, 1991:\1\
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    \1\There are additional submittals associated with moderate 
PM10 nonattainment plans, such as a permit program for the 
construction of new and modified major stationary sources and 
contingency measures. See sections 189(a) and 172(c)(9). These 
submittals were required to be submitted in 1992 and 1993, 
respectively, and are not the subject of today's proposal which 
addresses only those plan provisions required to be submitted on 
November 15, 1991.
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    1. Provisions to assure that reasonably available control measures 
(RACM) (including such reductions in emissions from existing sources in 
the area as may be obtained through the adoption, at a minimum, of 
reasonably available control technology--RACT) shall be implemented no 
later than December 10, 1993;
    2. Either a demonstration (including air quality modeling) that the 
plan will provide for attainment as expeditiously as practicable but no 
later than December 31, 1994 or a demonstration that attainment by that 
date is impracticable;
    3. Pursuant to section 189(c) of the Act, for plan revisions 
demonstrating attainment, quantitative milestones which are to be 
achieved every 3 years and which demonstrate reasonable further 
progress (RFP) toward attainment by December 31, 1994;\2\ and
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    \2\As will be seen below, the PM10 plan for the PPA does 
not demonstrate attainment by December 31, 1994, but rather includes 
the alternative demonstration that attainment by that date is 
impracticable. Therefore, section 189(c) does not apply and is not 
discussed further in this notice.
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    4. Provisions to assure that the control requirements applicable to 
major stationary sources of PM10 also apply to major stationary 
sources of PM10 precursors except where the Administrator 
determines that such sources do not contribute significantly to 
PM10 levels which exceed the NAAQS in the area. See sections 
172(c), 188, and 189 of the Act.

II. Today's Action

    Section 110(k) of the Act sets out provisions governing EPA's 
review of SIP submittals. See 57 FR 13565-66. In today's action, EPA is 
proposing to approve the plan revision submitted to EPA on August 11, 
1993, as revised by addenda submitted on March 3, 1994, for the PPA 
because it meets all of the applicable requirements of the Act.\3\
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    \3\One of the rules proposed for approval in today's notice 
contains a provision that may affect its enforceability. Because 
Maricopa County has agreed to expedite a revision and resubmission 
of this rule, EPA's proposed full approval of this rule is based on 
the assumption that this will occur prior to final action on this 
rulemaking. In the alternative, should a revision and resubmission 
not occur prior to EPA's final action, EPA proposes to approve all 
provisions of the rule, with the exception of the section affecting 
its enforceability. This issue is discussed in the section of this 
notice entitled ``Enforceability Issues.''
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A. Analysis of State Submission

1. Procedural Background
    The Act requires states to observe certain procedural requirements 
in developing implementation plans and plan revisions for submission to 
EPA. Section 110(a)(2) of the Act provides that each implementation 
plan submitted by a state must be adopted after reasonable notice and 
public hearing.\4\ Section 110(l) of the Act similarly provides that 
each revision to an implementation plan submitted by a state under the 
Act must be adopted by such state after reasonable notice and public 
hearing.
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    \4\Also section 172(c)(7) of the Act requires that plan 
provisions for nonattainment areas meet the applicable provisions of 
section 110(a)(2).
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    The EPA also must determine whether a submittal is complete and 
therefore warrants further EPA review and action. See section 110(k)(1) 
and 57 FR 13565. EPA's completeness criteria for SIP submittals are set 
out at 40 CFR Part 51, Appendix V (1993). EPA attempts to make 
completeness determinations within 60 days of receiving a submission. 
However, a submittal is deemed complete by operation of law if a 
completeness determination is not made by EPA six months after receipt 
of the submission.
    The State of Arizona originally submitted the implementation plan 
revision to EPA on November 15, 1991. Upon reviewing the plan for 
completeness, EPA deemed the plan incomplete because the Maricopa 
Association of Governments (MAG), the lead air quality planning agency 
for the PPA, did not hold a proper public hearing on the plan. The 
submittal also did not provide enough evidence to show that the State 
had the necessary authority to implement the locally adopted measures 
in the event that local governments did not implement those measures. 
By letter dated March 4, 1992, EPA informed the State that the 
submittal was incomplete.
    On July 22, 1993, MAG held another hearing to entertain public 
comment on a revised PM10 moderate area SIP revision. Following 
this public hearing the SIP revision was adopted by the State and 
submitted to EPA on August 11, 1993. Subsequently, the State revised a 
portion of the SIP revision based on the adoption of a Maricopa County 
fugitive dust rule, two Maricopa County reasonably available control 
technology (RACT) rules, and the subsequent revision of the SIP's 
demonstration that attainment of the PM10 NAAQS by the moderate 
area attainment date is not practicable. The State held an additional 
public hearing on February 28, 1994, adopted the revision, and 
submitted it to EPA on March 3, 1994.
    The SIP revision was reviewed by EPA to determine completeness 
shortly after its submittal, in accordance with the completeness 
criteria set out at 40 CFR Part 51, Appendix V (1993). EPA concluded 
that the State had addressed and corrected the two deficiencies which 
were the bases for the incompleteness finding of March 4, 1992. MAG had 
held a public hearing on the entire SIP revision, and the State had 
passed new legislation, Arizona State Senate Bill 1430, which gave the 
State the authority to take legal action against a local government if 
the State determines that the local government is not carrying out its 
responsibility to implement and enforce the control measures contained 
in the SIP revision. See Appendix B, exhibit 13 of the SIP revision. By 
letter dated September 7, 1993, EPA informed the Governor that the 
submittal was complete.
    In today's action EPA proposes to approve Arizona's PM10 SIP 
submittal for the PPA and invites public comment on the action. As 
explained more fully below, EPA is also taking comment on the 
appropriate method of reclassifying the PPA as a serious PM10 
nonattainment area.
2. Accurate Emissions Inventory
    Section 172(c)(3) of the Act requires that nonattainment plan 
provisions include a comprehensive, accurate, current inventory of 
actual emissions from all sources of relevant pollutants in the 
nonattainment area. Because such inventories are necessary to an area's 
attainment demonstration (or demonstration that the area cannot 
practicably attain), the emissions inventories must be received with 
the submission. See 57 FR 13539.
    Arizona submitted an emissions inventory for base year 1989. The 
base year inventory identifies re-entrained dust from paved roads and 
exhaust from gasoline and diesel powered vehicles as the primary causes 
of nonattainment, contributing over 80 percent of the total emissions 
during the time that the violations were recorded. Additional 
contributing sources include emissions from unpaved roads (1.5 
percent), fireplaces and wood stoves (5 percent), non-road mobile 
sources (2.5 percent), construction, demolition and farming activities 
(1.5 percent) and numerous other combustion and geologic sources (9.5 
percent).\5\
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    \5\This category includes: (1) combustion of fuels for 
industrial, commercial, residential, and agricultural purposes and 
power plants; (2) waste burning; and (3) geological emissions from 
metallurgical, mineral and mining industries.
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    EPA is proposing to approve the emissions inventory because it 
generally appears to be accurate and comprehensive, and provides a 
sufficient basis for determining the adequacy of the plan revision's 
air quality analysis consistent with the requirements of sections 
172(c)(3) and 110(a)(2)(K) of the Clean Air Act.\6\ For further details 
see the Technical Support Document (TSD) that is contained in the 
docket for today's proposed action.
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    \6\EPA issued guidance on PM10 emissions inventories prior 
to the enactment of the 1990 Clean Air Act Amendments in the form of 
the 1987 PM-10 SIP Development Guideline. Pursuant to section 193 of 
the Amendments, the guidance provided in this document, as well as 
all other pre-Amendment guidance cited in this notice, remains in 
effect.
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3. RACM (Including RACT)
    As noted, the initial moderate PM10 nonattainment areas must 
submit provisions to assure that RACM (including RACT) are implemented 
no later than December 10, 1993. See sections 172(c)(1) and 
189(a)(1)(C). EPA's General Preamble for the Implementation of Title I 
of the Clean Air Act Amendments contains a detailed discussion of EPA's 
interpretation of the RACM (including RACT) requirement. See 57 FR 
13540-45 and 13560-61.
    As stated in EPA's General Preamble the suggested starting point 
for determining RACM for a particular area is to list all of the RACM 
measures for which EPA has issued guidance under section 190 of the 
Act. If a state receives substantive public comment demonstrating that 
additional measures may be reasonably available, those measures should 
then be added to the original list. Chapter 5 of the SIP revision lists 
the 21 EPA RACM provided in a supplement to the General Preamble, 57 FR 
18070, Appendices C1-C3 (April 28, 1992).\7\ In addition to the EPA 
RACM, the SIP revision includes 58 measures developed by MAG for the 
1988 MAG particulate plan (MAG measures). These MAG measures include 
those designed specifically to reduce particulate matter emissions, as 
well as those developed for MAG's 1987 carbon monoxide SIP revision 
that could also reduce particulate matter emissions. Finally, as a 
result of the public hearing, 82 additional measures were added to the 
initial list of possible RACM, for a total of 161 measures.
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    \7\EPA's list of RACM for PM-10 was initially included in the 
memorandum from John Calcagni, Director, Air Quality Management 
Division, to Regional Air Division Directors, ``PM-10 Moderate Area 
SIP Guidance: Final Staff Work Product'', April 2, 1991. This 
memorandum was provided to the State and local air quality planners 
as guidance in developing the moderate area SIP revisions.
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    At this point, those measures for sources which do not contribute 
significantly to emissions from the area can be excluded from further 
consideration as not being reasonable. Three of the public comment 
measures were excluded as having a minimal impact on PM10 
emissions and are identified in Appendix B, Exhibits 5 and 12 of the 
SIP revision. In addition, six of the public comment measures were 
excluded because they relate to sources not present in the PPA due to 
its geographic or climatic conditions. These measures are identified in 
Appendix B, Exhibits 4 and 5 of the SIP revision.
    The next test for reasonableness is the technological and economic 
feasibility of implementing a measure in a particular area. Two of the 
public comment measures were deemed to be technologically infeasible in 
the PPA: congestion pricing and road pricing. According to information 
contained in Appendix B, Exhibit 4, this conclusion is based on a 
report developed by an EPA contractor entitled ``Improved Air Quality 
in Maricopa and Pima Counties--The Applicability of Transportation 
Measures'' (Cambridge Systematics, Inc., November 1986). This report is 
included in the docket accompanying this proposed rulemaking. Another 
measure deemed infeasible for the PPA was to implement tradable travel 
permits. According to information in Appendix B, Exhibit 5, this 
measure is considered a long term option due to the magnitude of change 
required for implementation.
    Two measures were determined to be economically infeasible. Non-
employee parking pricing was considered to be infeasible because 
businesses impacted by such costs would be put at a major disadvantage 
in competing with others not affected. See Appendix B, Exhibit 12. 
Electrification of railroads is not feasible due to the excessive cost 
of approximately $1.5 million per mile. See Appendix B, Exhibit 5.
    Four of the public comment measures affect emissions associated 
with aircraft and airports and are already being implemented by Sky 
Harbor Airport in Phoenix and the Federal Aviation Administration. 
These measures are identified in Appendix B, Exhibits 4 and 12. One 
measure addresses emission standards for new jet aircraft engines. 
Adoption of this type of control measure is outside the jurisdiction of 
the State or local governments and is identified in Appendix B, Exhibit 
5. One public comment measure involves the deregulation of private 
transit. However, according to the SIP revision in Appendix B, Exhibit 
5, there are currently no regulations in the PPA that restrict private 
transit operations.
    Of the remaining 62 measures submitted during the public comment 
period, 53 measures are essentially the same as the initial MAG 
measures and 9 measures were to be addressed in the State's 1993 SIP 
revisions for carbon monoxide and ozone.
    The revised list of possible RACM consists of 79 measures (21 EPA 
measures and 58 MAG measures). The Maricopa Association of Governments 
Air Quality Planning Committee (MAGAQPC) further excluded MAG measure 
#1 and portions of MAG measure #2 (described on page 6-14 of the SIP 
revision). These measures address broadening the State vehicle 
inspection and maintenance program (#1) and controls on diesel vehicles 
(#2). While MAG retained the portion of MAG measure #2 that addresses 
the use of number one diesel fuel, the other portions of that measure 
were excluded from further consideration because they were determined 
to be economically infeasible. See Appendix B, Exhibit 7.
    According to Chapter 6 of the SIP revision, 43 of the MAG measures 
were specifically adopted for the State's 1987 carbon monoxide (CO) 
SIP. As mentioned in the emission inventory section of this notice, 
exhaust from gasoline and diesel vehicles are also significant 
contributors to the PM10 nonattainment problem. The SIP's emission 
inventory identifies exhaust from gasoline vehicles as contributing 
about 20 percent of the total annual PM10 emissions and exhaust 
from diesel vehicles as contributing about 16 percent. These CO 
measures are included in the PM10 SIP revision because they could 
also reduce particulate matter emissions. These measures, identified in 
Chapter 6 of the SIP revision on pages 6-18 through 6-26, are designed 
to reduce vehicle exhaust emissions through strengthening the vehicle 
inspection and maintenance programs, requiring cleaner burning fuels in 
vehicles, relieving traffic congestion, and reducing vehicle miles 
traveled (VMT) by providing alternative modes of transportation. Many 
of the CO measures are transportation control measures (TCMs). In a 
November 14, 1991 conformity analysis of the MAG Transportation 
Improvement Plan and Regional Transportation Plan, EPA concluded that 
TCMs with quantifiable emission reductions were in fact being 
expeditiously implemented. A copy of this conformity analysis is 
included in the docket.
    Since the CO measures had already been implemented when the 
PM10 SIP revision was being prepared, any reduction benefits 
associated with them are built into the 1989 baseline PM10 
emission inventory and the 1994 projected PM10 emission inventory. 
Therefore the State has claimed no additional credit from reductions 
from these measures.
    The exclusion of these CO measures from the list of PM10 
possible RACM leaves 35 measures to be addressed: 21 EPA measures and 
14 MAG measures. However, in reviewing the remaining 14 MAG measures, 
EPA has determined that nine of these MAG measures are nearly identical 
to the EPA suggested RACM measures. One of the remaining five MAG 
measures, use of number one diesel fuel, would reduce particulate 
emissions because it is a cleaner burning fuel than other types of 
diesel fuel. However, EPA has addressed this type of measure on a 
national level in a Federal rulemaking. As of October 1, 1993, EPA 
implemented a new national program of diesel fuel quality control, 
requiring refiners to reduce the sulfur content of on-highway diesel 
fuel. See 55 FR 34120, August 21, 1990. As a result of this program, 
EPA estimates that total particulate emissions from diesel engines 
could be reduced up to 90 percent nationwide by 1995. The remaining 
four MAG measures address fugitive dust sources not specifically 
addressed by EPA's RACM measures. Local cities and towns in the 
nonattainment area were encouraged to develop regulations or programs 
to implement these measures, but no local regulations (i.e. regulations 
adopted by the cities and towns making up the nonattainment area) were 
included in the plan submitted to EPA. However, as discussed below, 
Maricopa County has adopted a countywide fugitive dust rule which EPA 
believes fully addresses fugitive dust sources in the PPA and 
incorporates the emission goals of these four remaining MAG measures.
    The final list of measures consists of the 21 EPA suggested RACM. 
The SIP's emission inventory identifies the major contributors to the 
PM10 nonattainment problem in the PPA as re-entrained dust on 
paved roads and other sources of fugitive dust including, but not 
limited to, construction and demolition activities, farming operations, 
uncovered haul trucks, and emissions from unpaved roads. These sources 
constitute over 50 percent of the PM10 emissions in the PPA and 
will be controlled by the implementation of Maricopa County Rule 310 
``Open Fugitive Dust Sources''. According to the State, implementation 
of this rule could reduce annual PM10 emissions in the urban 
portion of the PPA by approximately 1,427 to 3,991 tons per year. The 
low end of this range is based on the assumption that there will be no 
change in the current level of enforcement staff at the County and in 
the level of citizen complaint response. The high end assumes that all 
local governing bodies will cooperate in the enforcement of Rule 310, 
there will be a significant increase in citizen complaints due to 
greater public awareness of the requirements and impacts of Rule 310, 
and that the County will establish a 24 hour hotline to enable citizens 
to report violations of the rule. Section 189(a)(1)(C) of the Act 
requires RACM to be implemented by December 10, 1993. Rule 310 was 
implemented as of December 1, 1993.8
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    \8\See footnote 3.
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    The State claims emission reduction credits for some additional 
measures. Since 1989, Maricopa County has implemented a Trip Reduction 
Program which attempts to reduce VMT by encouraging the use of 
carpooling and mass transit. The SIP revision estimates that 
implementation of this measure throughout the nonattainment area will 
reduce VMT in 1994 by 0.8 percent or 315 tons per year. The State also 
claims credit for the use of two methanol buses in the PPA. This 
measure provides a small but quantifiable reduction in PM10 
emissions of 0.63 tons per year.
    Maricopa County also has an adopted regulation for the control of 
prescribed burning activities, Rule 314. This rule was already adopted 
prior to the development of this moderate area PM10 SIP so no 
additional emission reduction credits are associated with it. The 
emission reductions achieved from this rule are built into the baseline 
and projected emission inventories submitted with the SIP revision. 
Rule 314 applies throughout the nonattainment area.
    The General Preamble states that at a minimum all major stationary 
sources of PM10 in a nonattainment area be required to apply RACT. 
The State should then apply RACT to other PM10 sources in the 
area, taking into account the attainment needs of the area and the 
feasibility of such controls. Maricopa County has adopted regulations 
requiring RACT for stationary sources of PM10: Rule 311, 
``Particulate Matter from Process Industries'', and Rule 316, 
``Nonmetallic Mineral Mining and Processing''. These RACT rules apply 
throughout the nonattainment area and to all affected sources 
regardless of their size. The SIP does not claim emission reduction 
credits for Rule 311, since this was an existing regulation which the 
County revised in order to make it more enforceable. Rule 316 is a new 
regulation, but the County has stated that emission reduction credits 
would be difficult to quantify. The sources to which this rule will 
apply contribute only 1 percent to the total annual emission inventory.
    A more detailed discussion of the control strategy in the SIP 
revision can be found in the Technical Support Document (TSD).
    EPA believes that the State has provided a reasoned justification 
for eliminating measures from its initial list of possible RACM. The 
remaining measures are legally enforceable. In addition, the State has 
provided for the application of RACT to existing sources and new 
sources of PM10. Therefore, EPA has concluded that the regulations 
adopted for the State's moderate area PM10 SIP revision represent 
RACM (including RACT) as required by sections 189(a)(1)(C) and 172(c) 
of the Act. By this notice, EPA is proposing to approve the control 
strategy.
4. Demonstration
    As noted, the initial moderate PM10 nonattainment areas must 
submit a demonstration (including air quality modeling) showing that 
the plan will provide for attainment as expeditiously as practicable 
but no later than December 31, 1994. Alternatively, the state must show 
that attainment by December 31, 1994 is impracticable. See section 
189(a)(1)(B) of the Act.
    In order for a state to properly demonstrate attainment of the 
NAAQS, the SIP control strategy must provide for attainment of each 
primary ambient air quality standard. There are two primary air quality 
standards for PM10, a 24 hour standard (150 g/m3) and an 
annual standard (50 g/m3). The 24 hour standard is attained 
when the expected number of days per calendar year with a 24-hour 
average concentration above 150 g/m3 is equal to or less than 
one. The annual standard is attained when the expected annual 
arithmetic mean concentration is less than or equal to 50 g/m3 
(lid). See 40 CFR 50.6.
    Arizona used receptor modeling coupled with a proportional rollback 
model for its PPA air quality analysis. This analysis indicated that 
neither the 24 hour nor the annual standard for PM10 can be 
attained by December 31, 1994. The SIP revision indicates that a 27.2 
percent reduction in PM10 emissions would be necessary in order to 
attain the annual PM10 NAAQS in 1994. The State's analysis of the 
adopted control measures in the plan claims that the measures provide 
for a reduction of 11.1 percent. It should be noted however, that EPA, 
using the information contained in the plan, calculates that a 
reduction target of 22.8 percent is needed to attain the annual NAAQS 
and EPA's analysis of the control measures results in a reduction of 
18.8 percent. This difference in the control strategy's effectiveness 
is due to the fact that the State's analysis made an assumption that 
the control strategy would not be applied to the entire nonattainment 
area. However, Rule 310, the measure from which the greatest reductions 
in PM10 emissions would be realized, clearly applies to the entire 
PPA. The TSD accompanying this notice provides more detail on EPA's 
analysis of control measure effectiveness.
    Regardless of the difference in EPA's and the State's analysis of 
the control strategy's effect on the annual standard, the SIP's design 
value for the 24 hour PM10 NAAQS is 242 g/m3, 61 percent 
greater than the standard. Therefore even if the control strategy does 
provide a greater benefit than the State predicted, it still falls far 
short of meeting the 24 hour NAAQS. The control strategy used to 
achieve these design concentrations is summarized in the section of 
this notice entitled ``RACM (including RACT).''
    By this notice EPA is proposing to approve the State's 
demonstration that attainment of the PM10 NAAQS by December 31, 
1994 is impracticable. For a more detailed description of the 
demonstration of impracticability and the control strategy used, see 
the TSD accompanying this notice.
5. Reclassification
    Since EPA is proposing to approve the control strategy and the 
State's demonstration that attainment of the PM10 NAAQS by 
December 31, 1994 is impracticable, EPA has the discretion, pursuant to 
section 188(b)(1) of the Act, to propose to reclassify the PPA as a 
serious nonattainment area at this time. If the PPA is reclassified 
under this section of the Act, the State would have four years from the 
final reclassification to submit a demonstration (including air quality 
modeling) that the area will attain the PM10 NAAQS no later than 
December 31, 2001. See sections 188(c)(2) and 189(b)(2).
    In the alternative, EPA has the option to wait until after the 
moderate area attainment date, December 31, 1994, and then proceed 
under section 188(b)(2) of the Act. This provision requires EPA to 
determine by June 30, 1995 whether the PPA attained the PM10 
standard by December 31, 1994. If the Agency finds that the PPA is not 
in attainment after that date, the area is reclassified by operation of 
law as a serious area. If the PPA is reclassified under the section 
188(b)(2) procedure, the State would have to submit the serious area 
attainment demonstration within 18 months after reclassification. See 
section 189(b)(2).9
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    \9\It should be noted that when a moderate area is reclassified 
under either section 188(b)(1) or (b)(2), the State is required, 
within 18 months after reclassification, to submit provisions to 
assure that best available control measures (BACM) for the control 
of PM10 shall be implemented no later than four years after 
reclassification. For additional specific requirements relating to 
all serious PM10 areas, and to those serious areas seeking an 
extension of the attainment date, see section 189 of the Act.
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    EPA believes that there are advantages to pursuing reclassification 
under section 188(b)(2) and that the circumstances here justify such an 
approach. Under section 188(b)(1), the State would initially develop 
its BACM determination in the absence of an attainment demonstration 
with the potential result that the chosen measures would not ultimately 
attain the PM10 standards by the applicable attainment date. Such 
a result, however, would not be revealed until several years later, 
when the air quality modeling analysis is conducted for the attainment 
demonstration. If, at that point, additional measures are found to be 
necessary for the area to attain the PM10 NAAQS, new measures 
would have to be developed, adopted and submitted to EPA. In contrast, 
under section 188(b)(2), all the required elements of the serious area 
plan must be submitted to EPA within 18 months of reclassification. 
Thus, under section 188(b)(2), the process of attaining the PM10 
standards is expedited.
    Furthermore, it should be noted that the State originally concluded 
that the PPA could not practicably attain the PM10 NAAQS by 
December 31, 1994 when it developed its November 1991 plan submission. 
Despite procedural delays and plan updates culminating in the 1993 and 
1994 SIP submittals, this conclusion has not changed. Therefore, the 
State has been on notice for almost three years that reclassification 
was likely. Moreover, the moderate attainment date is now only several 
months away. EPA's current view is that under these circumstances, a 
delay of four years for the submission of a serious area attainment 
demonstration is unwarranted. Rather, the Agency believes that it is 
more appropriate to accelerate, to the maximum extent possible, the 
submission of a complete plan to attain the PM10 NAAQS.
    For the reasons set forth above, it is EPA's current intention to 
proceed under section 188(b)(2) as soon after December 31, 1994 as the 
Agency has the air quality data and other relevant information to 
determine whether the PPA has attained the NAAQS. In spite of the above 
analysis, however, EPA recognizes that there may be valid reasons to be 
advanced in favor of EPA's invoking its discretionary authority to 
reclassify the PPA at this time pursuant to section 188(b)(1). As a 
result, EPA is in this notice proposing to reclassify the PPA as a 
serious nonattainment area. However, in the absence of a compelling 
justification from the public during the comment period, EPA does not 
intend to take final action on this proposal.10 If EPA does not 
take final action on this proposal, the Agency will proceed under 
section 188(b)(2) after December 31, 1994.
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    \1\0If EPA does take final action on this proposal, the change 
in classification will appear in 40 CFR 81.303.
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6. PM10 Precursors
    The control requirements which are applicable to major stationary 
sources of PM10 also apply to major stationary sources of 
PM10 precursors, unless EPA determines such sources do not 
contribute significantly to PM10 levels in excess of the NAAQS in 
that area. See section 189(e) of the Act. An analysis of air quality 
and emissions data for the PPA nonattainment area indicates that 
exceedances of the NAAQS are attributable chiefly to direct particulate 
matter emissions from re-entrained dust from paved roads and exhaust 
from gasoline and diesel powered vehicles. Sources of particulate 
matter precursor emissions of ammonium sulfate and ammonium nitrate 
contribute only 3 percent to the total annual emissions of PM10. 
Consequently, EPA is proposing to find that major sources of precursors 
of PM10 do not contribute significantly to PM10 levels in 
excess of the NAAQS. The consequence of this finding is to exclude 
these sources from the applicability of PM10 moderate 
nonattainment area control requirements. Further discussion of the 
analyses and supporting rationale for EPA's finding are contained in 
the TSD accompanying this notice. Note that while EPA is making a 
general finding for this area, today's finding is based on the current 
character of the area including, for example, the existing mix of 
sources in the area. It is possible, therefore, that future growth 
could change the significance of precursors in the area. EPA intends to 
issue future guidance addressing such potential changes in the 
significance of precursor emissions in an area. It should be noted, 
however, that if the PPA is reclassified as a serious PM10 
nonattainment area, the State will be required to determine in its BACM 
analysis whether PM10 precursors contribute significantly11 
to ambient concentrations of PM10.
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    \1\1A source category in a serious PM10 nonattainment area 
will be presumed to be significant if its contribution to a 
violation of the 24 hour PM10 NAAQS exceeds 5 g/m\3\ 
or if its contribution to a violation of the annual NAAQS exceeds 1 
g/m\3\ (Memorandum from Joseph W. Paisie, Chief, SO2/
Particulate Matters Programs Branch, ``PM-10 Serious Area Guidance: 
Final Staff Work Product'' (September 24, 1993). For the moderate 
area RACM analysis, there is no presumptive level of significance; 
the determination is made on a case by case basis. See 57 FR 13539.
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7. Enforceability Issues
    The particular control measures contained in the SIP revision for 
the PPA are addressed above under the section entitled ``RACM 
(including RACT).'' These control measures apply to the types of 
PM10 emission sources identified in that discussion including, for 
example, dust on paved roadways, construction and demolition 
activities, unpaved roads, farming operations, uncovered haul trucks, 
prescribed burning, process industries, and nonmetallic mineral mining 
and processing.
    All measures and other elements in the SIP must be enforceable by 
EPA and the State. See sections 172(c)(6), 110(a)(2)(A) and 57 FR 
13556. The EPA criteria addressing the enforceability of SIPs and SIP 
revisions are stated in a September 23, 1987 memorandum (with 
attachments) from J. Craig Potter, Assistant Administrator for Air and 
Radiation, et al. See 57 FR 13541. The TSD for this notice contains 
detailed information on enforceability requirements including 
applicability, enforceable emission limitations, the source types 
subject to the rules, test methods and compliance schedules as 
appropriate, averaging times for compliance test methods, and reporting 
and recordkeeping requirements. Only enforceability issues meriting 
particular attention are addressed in this notice.
    Rule 310 contains a section which EPA believes threatens the 
enforceability of the rule. Section 221 of the rule lists the 
reasonably available control measures that a source can use in reducing 
PM10 emissions. These measures are all consistent with EPA 
recommended measures with the exception of section 221.9, which 
authorizes ``Other means approved by the Control Officer.'' This 
provision of the rule enables the Control Officer to approve 
alternative measures that may not meet the enforceability and other 
approvability criteria established by EPA.
    Following discussions with EPA on this issue, Maricopa County has 
agreed to revise the rule to delete section 221.9. However, the County 
must go through another public notice and comment period before the 
County Board of Supervisors will approve this change. The County 
intends to expedite its administrative procedures so that the rule can 
be revised and resubmitted to EPA prior to final action on this SIP 
revision. See letter, with attached draft rule revision and notice of 
public hearing, dated June 23, 1994 from Karen J. Heidel, Maricopa 
County Environmental Services Department to Dave Calkins, EPA. In 
today's action, EPA is proposing to approve Maricopa County Rule 310 on 
the assumption that it will be resubmitted with the noted change prior 
to final action on this rulemaking. In the alternative, if the County 
does not revise and resubmit the rule prior to EPA's final action, EPA 
proposes to approve all provisions of Maricopa County Rule 310 with the 
exception of section 221.9.
    Compliance for certain measures, such as Rules 310, 311, 314, and 
316 must be determined in accordance with appropriate test methods. The 
SIP revision provides that compliance with Rule 310 be determined in 
accordance with EPA reference method912. Rule 314 requires persons 
to obtain a permit from the Control Officer in order to conduct 
prescribed burning activities. Certain types of burning, as discussed 
in the TSD, must not exceed the County's visible emission standard of 
20 percent opacity. Rule 314 specifies that compliance with the opacity 
standard will be determined in accordance with reference method 9 
contained in the Arizona Testing manual. The State's method 9 is the 
same as EPA's method 9. Compliance with Rule 311 shall be determined in 
accordance with EPA reference methods 1, 2, 3, 4, 5, and 9. Compliance 
with Rule 316 shall also be determined in accordance with EPA reference 
methods 1 through 5 and 9. EPA believes these test methods are 
appropriate for determining compliance for the following reasons:
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    \1\2Compliance with Rule 310 is determined in accordance with 
EPA Method 9, except that opacity observations for intermittent 
visible emissions shall require 12 rather than 24 consecutive 
readings at 15 second intervals for the averaging time.
---------------------------------------------------------------------------

Rule 310, 314

    As mentioned above, compliance with these rules is determined using 
EPA reference method 9. While this test method is designed to determine 
opacity of smoke plumes from stationary sources, EPA believes that it 
is acceptable for determining compliance with these types of dust 
generating activities. While there is not a smokestack from which a 
plume emanates, EPA has not provided a more appropriate test method for 
determining compliance for sources such as these. Discussions with the 
Maricopa County Division of Air Pollution Control have indicated that 
the County enforcement personnel believe a more appropriate method 
needs to be devised and using method 9 on area source emissions can be 
difficult. However, they believe that method 9 can be reasonably 
utilized to determine the severity of visible emissions from the dust 
producing sources to which the rule applies. Since EPA cannot suggest a 
reasonable alternative test method that would provide better results, 
EPA proposes to approve this method of determining compliance.

Rule 311, Rule 316

    As mentioned above, Rules 311 and 316 utilize test methods 1 
through 5 and 9 to gauge compliance. These are all appropriate test 
methods to determine emissions from stationary sources. See 40 CFR Part 
60, Appendix A.
    In addition to meeting the enforceability requirements of the Act 
and EPA guidance, nonattainment area plan provisions must also contain 
a program that provides for enforcement of the control measures and 
other elements in the SIP. See sections 110(a)(2)(C) and 172(c)(7). 
Moreover, where the State relies on a local or regional government 
agency for implementing any plan provision, the State has the 
responsibility for ensuring adequate implementation of that provision. 
See section 110(a)(2)(E)(iii).
    The State of Arizona has a program that will ensure that the 
measures contained in the SIP revision are adequately enforced. Primary 
enforcement of the RACM and RACT rules will be under the jurisdiction 
of the Maricopa County Division of Air Pollution Control. Regarding the 
County's enforcement program, see ``MAG 1991 Particulate Plan for 
PM10 for the Maricopa County Area and 1993 Revisions--Revised 
Chapter 9 and Maricopa County Rules 310, 311 & 316, Responsiveness 
Summary,'' ADEQ.
    Under section 110(a)(2)(E)(iii) of the Act, the State must provide 
necessary assurances that the State has responsibility for ensuring 
adequate implementation of these plan provisions. The State has the 
authority to take legal action against the County if the State 
determines that the County is not carrying out its enforcement 
responsibilities. See Appendix B, Exhibit 13 of the SIP revision, 
Arizona State Senate Bill 1430.

III. Implications of Today's Action

    EPA is proposing to approve the moderate nonattainment area 
PM10 plan revision submitted to EPA for the Maricopa County Urban 
Planning Area on August 11, 1993 and amended on March 3, 1994. Among 
other things, the State of Arizona has demonstrated that the PPA cannot 
practicably attain the PM10 NAAQS by December 31, 1994. EPA is 
therefore proposing to reclassify the PPA as a serious nonattainment 
area at this time. However, EPA currently believes that the alternative 
approach authorized by the Clean Air Act of evaluating the area's 
attainment status after December 31, 1994 is a more appropriate 
approach. Therefore, in the absence of compelling countervailing 
arguments from the public, EPA does not intend to take final action on 
the reclassification proposal in this notice.
    As noted, additional submittals for the initial moderate PM10 
nonattainment areas were due at later dates. EPA will determine the 
adequacy of any such submittal as appropriate.

IV. Request for Public Comments

    EPA is requesting comments on all aspects of today's proposal. As 
indicated at the outset of this notice, EPA will consider any comments 
received by (30 days from date of publication).

V. Executive Order 12866

    This action has been classified as a Table 2 action by the Regional 
Administrator under the procedures published in the Federal Register on 
January 19, 1989, (54 FR 2214-2225), as revised by an October 4, 1993, 
memorandum from Michael H. Shapiro, Acting Assistant Administrator for 
Air and Radiation. The Office of Management and Budget has exempted 
this regulatory action from Executive Order 12866 review.

VI. Regulatory Flexibility

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

List of Subjects in 40 CFR Part 52

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

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

    Dated: July 11, 1994.
Felicia Marcus,
Regional Administrator.
[FR Doc. 94-18334 Filed 7-27-94; 8:45 am]
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