[Federal Register Volume 59, Number 120 (Thursday, June 23, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-15260]


[[Page Unknown]]

[Federal Register: June 23, 1994]


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ENVIRONMENTAL PROTECTION AGENCY
 

40 CFR Part 52

[WA3-1-5479a; FRL-4997-6]

Approval and Promulgation of State Implementation Plans: Washington

AGENCY: Environmental Protection Agency.

ACTION: Final rule.

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SUMMARY: In this action, Environmental Protection Agency (EPA) 
conditionally approves the State implementation plan (SIP) revisions 
submitted by the State of Washington for the purpose of bringing about 
attainment of the National ambient air quality standards (NAAQS) for 
particulate matter with an aerodynamic diameter less than or equal to a 
nominal 10 micrometers (PM-10). The implementation plan was submitted 
by the State to satisfy certain Federal Clean Air Act requirements for 
an approvable moderate nonattainment area PM-10 SIP for Seattle, 
Washington due on November 15, 1991.
DATES: This final rule will be effective on August 22, 1994, unless 
adverse or critical comments are received by July 25, 1994. If the 
effective date is delayed, timely notice will be published in the 
Federal Register.

ADDRESSES: Written comments should be addressed to: Montel Livingston, 
SIP Manager, EPA, Air Programs Branch (AT-082), 1200 Sixth Avenue, 
Seattle, Washington 98101.
    Documents which are incorporated by reference are available for 
public inspection at the Air and Radiation Docket and Information 
Center, EPA, 401 M Street, SW., Washington, DC 20460. Copies of 
material submitted to EPA may be examined during normal business hours 
at the following locations: EPA, Air Programs Branch, 1200 Sixth Avenue 
(AT-082), Seattle, Washington 98101, and the State of Washington 
Department of Ecology, 4450 Third Ave. SE., Lacey, Washington 98504.

FOR FURTHER INFORMATION CONTACT: George Lauderdale, Air Programs Branch 
(AT-082), EPA, 1200 Sixth Avenue, Seattle, Washington 98101, (206) 553-
6511.

SUPPLEMENTARY INFORMATION:

I. Background

    The Seattle, Washington, area was designated nonattainment for PM-
10 and classified as moderate under sections 107(d)(4)(B) and 188(a) of 
the Clean Air Act, by operation of law upon enactment of the Clean Air 
Act Amendments of 1990.1 See 56 FR 56694 (Nov. 6, 1991) (official 
designation codified at 40 CFR 81.348). The air quality planning 
requirements for moderate PM-10 nonattainment areas are set out in 
subparts 1 and 4 of part D, title I of the Act.2 The EPA has 
issued a ``General Preamble'' describing EPA's preliminary views on how 
EPA intends to review SIP's and SIP revisions submitted under title I 
of the Act, including those State submittals containing moderate PM-10 
nonattainment area SIP requirements (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 thisproposal and the supporting 
rationale. In this rulemaking action on the Washington moderate PM-10 
SIP for the Seattle nonattainment area, EPA applies its 
interpretations, taking into consideration the specific factual issues 
presented. Additional information supporting EPA's action on this 
particular area is available for inspection at the address indicated 
above.
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    \1\The 1990 Amendments to the Clean Air Act made significant 
changes to the Act. See Pub. L. No. 101-549, 104 Stat. 2399. 
References herein are to the Clean Air Act, as amended (``the 
Act''). The Clean Air Act is codified, as amended, in the U.S. Code 
at 42 U.S.C. 7401, et seq.
    \2\Subpart 1 contains provisions applicable to nonattainment 
areas generally and subpart 4 contains provisions specifically 
applicable to PM-10 nonattainment areas. At times, subpart 1 and 
subpart 4 overlap or conflict. EPA has attempted to clarify the 
relationship among these provisions in the ``General Preamble'' and, 
as appropriate, in today's notice and supporting information.
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    Those States containing initial moderate PM-10 nonattainment areas 
(those areas designated nonattainment under section 107(d)(4)(B)) were 
required to submit, among other things, the following provisions by 
November 15, 1991:

    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. Quantitative milestones which are to be achieved every 3 years 
and which demonstrate reasonable further progress (RFP) toward 
attainment by December 31, 1994; and
    4. Provisions to assure that the control requirements applicable to 
major stationary sources of PM-10 also apply to major stationary 
sources of PM-10 precursors except where the Administrator determines 
that such sources do not contribute significantly to PM-10 levels which 
exceed the NAAQS in the area. See sections 172(c), 188, and 189 of the 
Act.

    Some provisions are due at a later date. States with initial 
moderate PM-10 nonattainment areas were required to submit a permit 
program for the construction and operation of new and modified major 
stationary sources of PM-10 by June 30, 1992 (see section 189(a)). Such 
States also were to submit contingency measures by November 15, 1993, 
which become effective without further action by the State or EPA, upon 
a determination by EPA that the area has failed to achieve RFP or to 
attain the PM-10 NAAQS by the applicable statutory deadline (see 
section 172(c)(9) and 57 FR 13543-13544).

II. This Action

    Section 110(k) of the Act sets out provisions governing EPA's 
review of SIP submittals (see 57 FR 13565-13566). Section 110(k)(4) of 
the Act authorizes EPA to approve a plan revision based on a commitment 
by the State to adopt specific enforceable measures by a date certain, 
but not later than one year after the date of approval of the plan 
revision. EPA would then assess the approvability of the submittal 
after the State fulfilled its commitment. However, if the State fails 
to comply with its commitment, section 110(k)(4) provides that a 
conditional approval shall be treated as a disapproval. The conditional 
approval would become a disapproval upon notification of the State by 
letter. EPA would subsequently publish a document in the Federal 
Register announcing such action. If the conditional approval is 
converted to a disapproval, the sanctions clock under section 179(a) of 
the Act and the Federal implementation plan clock under section 
110(c)(1) of the Act will begin.
    In this action, EPA is granting conditional approval of the plan 
revisions submitted to EPA for Seattle, Washington, on November 5, 
1990, December 27, 1990, November 15, 1991, and May 11, 1994 (hereafter 
generally referred to as a single submittal). EPA conditionally 
approves the submittal because it meets many of the applicable 
requirements of the Act and contains a commitment from the State to 
adopt specific enforceable measures on or before January 1, 1995, to 
address remaining applicable requirements of the Act. EPA approves the 
exclusion from precursor controls as described in part II. 5 below. In 
addition, EPA approves certain control measures contained in the 
Seattle plan submittals which generally strengthen the plan.

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.3 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. 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). The EPA's completeness criteria for SIP 
submittals are set out at 40 CFR part 51, appendix V (1992). The 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.
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    \3\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 State of Washington Department of Ecology (WDOE) and the Puget 
Sound Air Pollution Control Agency (PSAPCA) held a joint public hearing 
to receive public comment on the original Seattle implementation plan 
on December 8, 1988. WDOE adopted the implementation plan for the area 
on November 3, 1990 and the plan was submitted to EPA on November 5, 
1990. The plan was subsequently revised on December 27, 1990, November 
15, 1991, and May 11, 1994. WDOE held appropriate public hearings prior 
to submittal of each of the SIP revisions to entertain public comment. 
The SIP submittal was reviewed by EPA to determine completeness in 
accordance with the completeness criteria set out at 40 CFR part 51, 
appendix V. A letter dated February 13, 1992, was forwarded to the WDOE 
indicating the completeness of the submittal and the next steps to be 
taken in the review process.
2. PM-10 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 the submission of the emissions inventory 
is a necessary adjunct to an area's attainment demonstration (or 
demonstration that the area cannot practicably attain) the emissions 
inventory must be received with the demonstration (see 57 FR 13539).
    WDOE submitted an emissions inventory of estimated actual emissions 
for the base year of 1986 and the attainment year of 1991. The annual 
and 24-hour emission inventories identified four major source 
categories contributing to particulate matter concentrations in the 
valley. These are, in descending order of greatest contribution, 
vehicle resuspended dust (48%); industrial stack emissions (30%), motor 
vehicle emissions (9%) and industrial fugitive emissions (7%). 
Residential wood combustion is a relatively smaller source of PM-10 
within the nonattainment area boundaries. However, the plan does 
include control measures for residential wood combustion because there 
is a large population of woodstoves and fireplaces adjacent to the 
nonattainment area, and throughout the metropolitan area. WDOE has 
determined all other sources to be insignificant within the 
nonattainment area.
    The emissions inventory estimating actual emissions generally 
appears to be accurate and comprehensive, and provides a sufficient 
basis for determining the technical adequacy of the attainment 
demonstration for this area consistent with the requirements of section 
172(c)(3) of the Clean Air Act.4 An important attainment year 
emission inventory issue, relating to the attainment demonstration, and 
other requirements, is the use of actual instead of allowable emission 
estimates for projecting attainment. This issue will be discussed in 
detail under the demonstration section of this document. For further 
information the reader is referred to the Technical Support Document 
(TSD) corresponding with this action, which is available at the EPA 
address indicated above.
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    \4\The EPA issued guidance on PM-10 emissions inventories prior 
to the enactment of the Clean Air Act Amendments in the form of the 
1987 PM-10 SIP Development Guideline. The guidance provided in this 
document appears to be consistent with the Act.
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3. RACM (Including RACT)
    As noted, the initial moderate PM-10 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)). The General Preamble contains a detailed discussion of 
EPA's interpretation of the RACM (including RACT) requirement (see 57 
FR 13539-13545 and 13560-13561).
    The Seattle emission inventory identified industrial fugitive 
emissions and resuspended road dust as the significant contributors of 
fugitive dust emissions. PSAPCA's fugitive dust regulation (Regulation 
I, section 9.15) was designed to reduce fugitive dust from commercial 
and industrial activities and also to reduce dust emissions from paved 
and unpaved roads and parking lots.
    PSAPCA requires ``Best Available Control Technology (BACT)'' under 
section 9.15 for all fugitive emissions from all incinerators, boilers, 
manufacturing equipment and air pollution control equipment. The 
Seattle attainment plan lists and documents emission reductions from 
several major facilities that were required to add PM-10 controls as 
the result of PSAPCA's application of section 9.15. EPA accepts the 
emission reductions claimed from this control measure as reasonable. 
Since it is generally impractical to source test fugitive emission 
sources, a SIP must rely on calculated emission estimates, and control 
efficiency estimates, to arrive at emission reduction estimates.
    PSAPCA applies the same section 9.15 BACT provisions to dust 
emissions from both private and public paved and unpaved roads. In 
addition, all private roadways adjoining paved public roads and all 
commercial properties with access points abutting paved public roads in 
the Seattle nonattainment area are required to implement BACT to 
stabilize vehicular entrances and exits. The control measure 
appropriately prioritized preventing material deposition over 
mitigating measures after deposition. The plan uses an overall emission 
reduction credit of 37% from resuspended road dust. EPA accepts this 
estimate as reasonable.
    Another source of PM-10 pollution is residential wood combustion. 
PSAPCA initiated a voluntary woodsmoke curtailment program throughout 
its four county jurisdictional area, including Seattle, in the winter 
of 1987-88. The program changed to mandatory curtailment beginning with 
the 1988-89 heating season, pursuant to WAC 173-433 and the PSAPCA 
Regulation I, Article 13. The curtailment program is a two stage plan. 
At Stage I, which is imposed when ambient PM-10 levels reach 75 
g/m3, the use of uncertified stoves and fireplaces are 
banned. At Stage II, imposed when PM-10 levels reach 105 g/
m3, all wood heating (fireplaces, certified and uncertified 
woodstoves) is prohibited. The program exempts homes with no other 
source of heat. WDOE and PSAPCA regulations contain additional 
controls, including the prohibition of all fuels except dry, seasoned 
wood in woodheating devices. Plume opacity for woodheating devices is 
limited to 20%, with brief allowances for fire starting and stoking. 
PSAPCA serves as the primary enforcement agency for the curtailment and 
opacity portions of the control program. Both PSAPCA and WDOE 
administer public education programs targeted at residential wood 
burning. Throughout the State, WDOE also enforces a ban on the sale of 
uncertified woodstoves.
    The strength and depth of the legislated woodsmoke program, and the 
size and historical effectiveness of the agencies involved, 
demonstrates to EPA's satisfaction that the Seattle area is achieving a 
sufficient compliance rate to justify the 70% emission reduction 
credit. In addition, Ecology expects the implementation of part of the 
King County Board of Health (KCBH) Regulation 70 (Title 16 of the Code 
of the King County Board of Health) to further reduce daily woodstove 
emissions; this will assist in maintaining the standard through 1994. 
The KCBH requirement that uncertified woodstoves be removed on sale of 
a home is estimated to reduce background particulates and result in a 
36 kg/day reduction in the nonattainment area. EPA accepts this 
estimate as reasonable and notes that Ecology did not seek credit for 
several other control measures contained in the King County regulation 
which could reasonably be expected to result in additional PM-10 
emission reductions. A more detailed analysis of the Washington 
woodsmoke curtailment plan and other residential wood combustion 
measures is contained in the TSD.
    The attainment plan contains a control measure directed at 
prescribed burning even though the emission inventory for the 
nonattainment area does not indicate prescribed burning as a major 
source. The 1991 Clean Air Washington Act added additional restrictions 
to general outdoor and prescribed burning in the Seattle nonattainment 
area. In response to the new provision of the Act, PSAPCA banned all 
outdoor burning in the Federal Aid Urban Area (much larger than the 
nonattainment area) effective September 1, 1992. This strengthened 
PSAPCA's previous regulation restricting open burning by expanding the 
area covered. The November 15, 1991, submittal contains a 24 kg/day 
emission credit that reduces the background concentrations for the 
Seattle nonattainment area. EPA considers the estimation reasonable and 
approves the reduction credit.
    Ecology proposed in the November 15, 1991, submittal an emission 
reduction credit of 85 kg/day for implementation of a Washington State 
law requiring major employers to reduce single occupant vehicle 
commuting by 15 percent by January 1, 1995. Inthe April 1992 
supplement, Ecology revised the emission estimate to 14 kg/day based on 
more recent data.
    EPA approves the 14 kg/day credit for the control measure as a 
reasonable estimate of the impact of the law. This technical conclusion 
is based on the information provided in the April 1992 ``Supplement 
Addendum.'' EPA has information that the law is being implemented in 
the Seattle nonattainment area. Ecology submitted RWC 70.94, 521-551, 
authorizing a Transportation Demand Management program, on November 13, 
1992 as part of a carbon monoxide SIP revision. EPA approves the 
measure as part of the Seattle PM-10 attainment plan.
    Ecology began implementing a new program on July 1, 1993, to 
inspect diesel fueled vehicles. The program includes a simple pass/fail 
opacity test. The November 15, 1991, SIP submittal estimates an 
emission reduction of 47 kg/day from implementation of the program. In 
the April 1992 supplement, based on more recent data, the estimate was 
revised to 50 kg/day. EPA approves the 50 kg/day emission reduction 
credit as reasonable. The measure was submitted as a ``contingency 
measure'' in the November 15, 1991, SIP revision. The measure is more 
appropriately a control measure because it is relied on to maintain air 
quality below the standards through 1994. The April 1992 supplement 
from Ecology agrees with this view. The regulation was submitted with a 
1992 carbon monoxide SIP revision and EPA proposes to approve those 
portions of the regulation which apply to the diesel inspection and 
maintenance program.
    The November 15, 1991, SIP submittal contained emission reduction 
credits from the implementation of the Federal requirement reducing 
sulfur content in diesel fuel. The credit taken by Ecology is the same 
as the credit estimated by EPA, 7.5%. This credit translates to 
emission reductions of 19 kg/day. EPA accepts this credit as a 
reasonable estimate of emission reductions from the implementation of 
the Federal requirement. As with the diesel I/M program, the control 
measure was originally submitted as a ``contingency measure,'' when the 
measure is really an additional control measure necessary to maintain 
the standards through 1994. Since the measure is federally required, 
Ecology does not need to include another legally enforceable regulation 
in the SIP.
    The stack emissions in the Seattle nonattainment area were being 
controlled prior to the development of the PM-10 plan to a degree 
PSAPCA and Ecology consider reasonably available control technology. 
PSAPCA did review and modify several regulations to generally 
strengthen control of stack sources but did not request any additional 
emission reduction credit. In 1988, additional wording was added to 
PSAPCA regulations to emphasize operation and maintenance of control 
equipment and several emission standards were strengthened. Control 
equipment for stack sources in the Seattle area include traditional 
electrostatic precipitators, baghouses, etc. There are 10 stack sources 
in the Seattle area that were included in the emission inventory. The 
sources ranged in size from 119 tons per year (controlled) to two tons 
per year (controlled). The plan requests no emission reduction credit 
from any additional control of stack emissions. EPA accepts this 
determination.
    Where sources of PM-10 contribute insignificantly to the PM-10 
problem in the area, EPA's policy is that it would be unreasonable (and 
would not constitute RACM) to require the implementation of potentially 
available control measures. 57 FR 13540. Further, EPA has indicated 
that for some sources in areas which demonstrate attainment, RACM does 
not require the implementation of otherwise available control measures 
that are not ``reasonably'' available because their implementation 
would not expedite attainment (See 57 FR 13543). In the Seattle 
situation, EPA believes the significant sources, as well as several 
less significant sources, of PM-10 in the area have been reasonably 
controlled. Thus, EPA believes it would be unreasonable to require 
other de minimis sources of PM-10 in the area to implement potentially 
available control measures or technology. Further, EPA believes 
implementation of such additional controls in this area would not 
expedite attainment.
    A more detailed discussion of the individual source contributions, 
their associated control measures and an explanation as to why certain 
available control measures were not implemented, can be found in the 
TSD. EPA has reviewed the State's explanation and associated 
documentation and concludes that it adequately justifies the control 
measures to be implemented. As addressed in more detail in part II.4. 
below, not all of the emission reductions necessary to assure 
expeditious attainment of the PM-10 NAAQS have been converted to 
enforceable emission limitations. Thus, EPA is approving all control 
measures for their general SIP strengthening effect. The only exception 
is that EPA conditionally approves the emission estimates used for the 
stack sources. Ecology will submit to EPA by January 1, 1995, legally 
enforceable emission limits for the significant stack sources in 
Seattle. This conditional approval is discussed further in the section 
below.
4. Demonstration
    As noted, the initial moderate PM-10 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, (see section 189(a)(1)(B) of the 
Act). The General Preamble sets out EPA's guidance on the use of 
modeling for moderate area attainment demonstrations (57 FR 13539). 
Alternatively, if the State does not submit a demonstration of 
attainment, the State must show that attainment by December 31, 1994 is 
impracticable (section 189(a)(1)(B)(ii).
    PSAPCA in conjunction with WDOE conducted an attainment 
demonstration in the Seattle, Washington, nonattainment area. The 
dispersion modeling conducted employed WYNDvalley in combination with 
RAM. WYNDvalley is a non-guideline dispersion model that the EPA 
Regional Meteorologist approved for use in Seattle due to very low wind 
speeds occurring during periods of historical exceedances. RAM, which 
is a guideline model, was used to model emissions from stack sources, 
while WYNDvalley was used for all other sources. Outputs from both 
models were then combined for each grid cell to yield a cumulative 
impact estimate.
    PSAPCA employed this combination of models because RAM is believed 
to more accurately represent dispersion patterns at the greater release 
heights of the valley's industrial stacks, though its predictions of 
ambient concentrations are less reliable during periods of air 
stagnation. WYNDvalley, on the other hand, was designed for use in 
stagnant conditions, but fails to predict the impact of those emissions 
that may rise above the height of the inversion layer. Receptor 
modeling was not used in the attainment demonstration.
    A major problem with the attainment demonstration is the attainment 
year emission inventory used for point (stack) sources. The inventory 
was based on actual emission estimates. EPA's Guideline on Air Quality 
Models (Revised, July 1986) generally requires use of allowable 
emissions in inventories for the purposes of modeling attainment of the 
NAAQS (see also section 110(a)(2)(K) of the Act). The requirement takes 
into consideration possible increases from existing sources allowed by 
their permits, registrations, or other regulatory mechanisms. Ecology 
and PSAPCA, based on comments from EPA, were not able to demonstrate 
that all point source emissions in the nonattainment area would be 
unable to increase significantly above actual levels. Consequently, 
there is no objective assurance, or legally enforceable mechanism in 
place, to restrict a point source from emitting above the estimated 
actual rate, should the source have the physical capacity. Therefore, 
the current SIP cannot assure that the NAAQS will be protected in the 
Seattle nonattainment area. Although Seattle has accumulated five years 
of data with no exceedances of the NAAQS, there are no legal limits in 
place to prevent future increases from a few industrial facilities that 
could consequently threaten attainment of the NAAQS. Ecology submitted 
on May 11, 1994, a request for conditional approval of the Seattle 
nonattainment plan based on a commitment to reconcile the actual/
allowable issue. Ecology's commitment is based on PSAPCA's schedule to 
issue regulatory orders to appropriate point sources within the 
nonattainment area that will restrict emissions at or below the 
``actual'' emission estimates used in the attainment demonstration.
    The November 15, 1991, SIP revision contained a three year 
maintenance demonstration that was based on an outdated emission 
inventory. After EPA notified Ecology of this error, supplemental 
information was submitted on April 29, 1992. The April 1992, 
``Supplemental Addendum'', although not a formal SIP revision, provides 
a replacement three year maintenance demonstration, which includes the 
expected growth in emissions from 1991 to 1994, and describes the 
control measures that Ecology expects will offset the increased 
emissions.
    Technical analysis provided in both the November 1991, and April 
1992, submittals utilized proportional modeling to perform the air 
quality modeling to demonstrate maintenance to the year 1994. In the 
Seattle situation, Ecology used dispersion modeling for the attainment 
demonstration and proportional modeling for the maintenance 
demonstration. While recognizing that dispersion modeling would have 
been the preferred method to provide evidence that the PM-10 standards 
would be maintained for a three year period after attainment, EPA 
accepts the proportional modeling demonstration of maintenance. The 
Region considered actual monitoring data for the projected attainment 
year (1991) and the two subsequent years (1992 and 1993). Neither the 
24 hour nor annual PM-10 standard were exceeded in any of those three 
years. In addition, the standards were not exceeded in 1989 or 1990. In 
1988 one exceedance was recorded at one of the three monitoring sites 
in the nonattainment area. EPA believes that it is reasonable to expect 
that the proportional modeling is adequate to predict the three year 
maintenance demonstration in the Seattle situation.
    The existence of five years of daily PM-10 monitoring values 
without any 24 hour or annual exceedances, through and beyond the 
attainment plans 1991 attainment year, provides particularly convincing 
evidence that both the attainment and the three year maintenance 
modeling were reasonably accurate.
    The technical modeling analysis described above confirmed that 
attainment can be demonstrated in Seattle and could be maintained in 
future years using actual emission estimates. The 24-hour PM-10 NAAQS 
is 150 micrograms/cubic meter (g/m3), and the 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 (see 40 CFR 50.6). The annual PM-10 NAAQS is 50 
g/m3, and the standard is attained when the expected 
annual arithmetic mean concentration is less than or equal to 50 
g/m3 (id.). The demonstration predicted that the 24-hour 
design concentration in the attainment year of 1991 will be below 150 
g/m3, thus demonstrating attainment of the 24-hour PM-10 
NAAQS. The highest 24-hour value in 1993 was 126 g/m3 . 
Ambient data show that the area exceeded the annual standard only one 
year, for the calendar year 1985 (54 g/m3). The value for 
the 1991 annual average was 37 g/m3. Since no annual 
NAAQS exceedances have been noted with the current emissions inventory 
and since the inventory was modeled using appropriate dispersion 
modeling to show attainment of the 24-hour NAAQS, no violations of the 
annual NAAQS are likely. Nevertheless, WDOE prepared and submitted a 
proportional modeling analysis which demonstrated that the annual 
standard was, indeed, attained in 1991 and will be maintained until at 
least 1994. Therefore, EPA believes that WDOE has adequately 
demonstrated that the annual standard will be attained in the Seattle 
nonattainment area, using actual emission estimates.
    EPA conditionally approves the Seattle demonstration based on a 
commitment from the State to adopt specific enforceable measures on or 
before January 1, 1995, that will convert certain actual source 
emission to enforceable allowable emission limitations. The control 
strategy used to achieve these design concentrations is summarized in 
the section titled ``RACM (including RACT).'' For a more detailed 
description of the attainment demonstration and the control strategy 
used, see the TSD.
5. PM-10 Precursors
    The control requirements which are applicable to major stationary 
sources of PM-10, also apply 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 that area (see 
section 189(e) of the Act). The General Preamble contains guidance 
addressing how EPA intends to implement section 189(e) (see 57 FR 
13539-13540 and 13541-13542).
    In 1985 a limited receptor modeling study was conducted in the 
Seattle nonattainment area. The study had several technical problems 
and was not used in the attainment/ maintenance demonstration. However, 
the study did contain adequate information to determine the likelihood 
of precursor problems in the area. The results of this study indicated 
that sulfates contributed roughly 10 percent of the mass measured on 
the PM-10 samples collected in the Seattle nonattainment area. Nitrate 
impacts were much less. Consequently, EPA believes that stationary 
sources of precursors provide an insignificant contribution to the 
Seattle, Washington, ambient PM-10 concentration and EPA grants the 
area an exclusion from PM-10 precursor control requirements authorized 
under section 189(e) of the act. Note that while EPA is making a 
general finding for this area, this 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.
6. Quantitative Milestones and Reasonable Further Progress (RFP)
    The PM-10 nonattainment area plan revisions demonstrating 
attainment must contain quantitative milestones which are to be 
achieved every three (3) years until the area is redesignated 
attainment and which demonstrate RFP, as defined in section 171(1), 
toward attainment by December 31, 1994 (see section 189(c) of the Act). 
Reasonable further progress is defined in section 171(1) as such annual 
incremental reductions in emissions of the relevant air pollutant as 
are required by part D or may reasonably be required by the 
Administrator for the purpose of ensuring attainment of the applicable 
NAAQS by the applicable date.
    In implementing RFP for this initial moderate area, EPA has 
reviewed the attainment demonstration and control strategy for the area 
to determine whether annual incremental reductions, different from 
those provided in the SIP, should be required in order to ensure 
attainment of the PM-10 NAAQS by December 31, 1994 (see section 
171(1)). The State of Washington's PM-10 SIP for Seattle demonstrates 
attainment in 1991 and maintenance through 1994, and therefore would 
normally satisfy the initial quantitative milestone requirement (see 57 
FR 13539). However, as mentioned previously, Ecology and PSAPCA based 
attainment and maintenance demonstrations on actual emission estimates 
instead of the required allowable rates. The State has committed to 
adopt the necessary enforceable allowable emission limits by January 1, 
1995. Accordingly, as with other requirements discussed elsewhere in 
this document, EPA is conditionally approving the submittal relative to 
the RFP and initial milestone requirements.
7. Enforceability Issues
    All measures and other elements in the SIP must be enforceable by 
WDOE and EPA (see sections 172(c)(6), 110(a)(2)(A) and 57 FR 13556). 
EPA criteria addressing the enforceability of SIP's and SIP revisions 
were 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). Nonattainment area plan provisions must also contain 
a program that provides for enforcement of the control measures and 
other elements in the SIP (see section 110(a)(2)(C)).
    WDOE's control measures and regulations for control of Particulate 
Matter, which are contained in the SIP, are addressed above under the 
section headed ``RACM (including RACT).'' These control measures apply 
to the types of activities identified in that discussion including, for 
example, fugitive emissions from point sources; vehicle resuspended 
road dust; and residential wood combustion. The SIP provides that the 
affected activities will be controlled throughout the entire 
nonattainment area.
    Consistent with the attainment demonstration described above, the 
SIP requires that all the applicable SIP provisions must be implemented 
by December 10, 1993 (section 189(a)(1)(C). In addition to the 
applicable control measures, this includes the applicable record-
keeping requirements which are addressed in the supporting technical 
information.
    The TSD contains further information on enforceability requirements 
including enforceable emission limitations; a description of the rules 
contained in the SIP and the source types subject to them; test methods 
and compliance schedules; malfunction provisions; excess emission 
provisions; correctly cited references of incorporated methods/rules; 
and reporting and recordkeeping requirements. The local air pollution 
control agency, PSAPCA, has the primary responsibility for implementing 
the measures in the plan. PSAPCA has many compliance inspectors and, as 
discussed further in the TSD, EPA considers PSAPCA's staffing level 
adequate to assure that the Seattle attainment plan is fully 
implemented. As a necessary adjunct of its enforcement program, PSAPCA 
also has broad powers to adopt rules and regulations, issue orders, 
require access to records and information, and receive and disburse 
funds. WDOE has adequate authority to implement and enforce the plan in 
the event PSAPCA fails to make a good faith effort to implement the 
regulations.
    The residential wood combustion program, fugitive dust control 
measures, the diesel inspection program, the transportation demand 
management program, and the land clearing fire ban are enforceable. 
Discussion and justification of EPA's reasoning can be found in the 
control measure section of this document and the TSD.
    However, as discussed elsewhere in this document, the use of actual 
emission estimates rather than the significantly higher emission limits 
allowed in the current PSAPCA regulations is unacceptable. EPA only 
could enforce the allowable emissions that are currently contained in 
the PSAPCA regulations. There are no mechanisms for EPA to enforce the 
emission estimates used in the attainment demonstration because they 
are well below the legal limits allowed in the PSAPCA regulations.
    A discussion regarding the use of actual instead of allowable 
emissions contained in the demonstration portion of this proposed 
action provides background for the enforceability decision. The Region 
recommends conditional approval of the Seattle attainment plan based on 
the commitment contained in the May 11, 1994, submittal which will make 
the emissions from point sources enforceable at or below the actual 
emission levels used to demonstrate attainment and maintenance. EPA 
will need additional technical documentation from Ecology if the 
emission levels in the regulatory orders are greater than those used in 
the attainment and three year maintenance demonstrations.
8. Contingency Measures
    As provided in section 172(c)(9) of the Act, all moderate 
nonattainment area SIP's that demonstrate attainment must include 
contingency measures (see generally 57 FR 13543-13544). These measures 
must be submitted by November 15, 1993, for the initial moderate 
nonattainment areas. Contingency measures should consist of other 
available measures that are not part of the area's control strategy. 
These measures must take effect without further action by the State or 
EPA, upon a determination by EPA that the area has failed to make RFP 
or attain the PM-10 NAAQS by the applicable statutory deadline.
    The Seattle, Washington, plan contains several control measures 
which Ecology originally considered contingency measures (November 15, 
1991 SIP submittal). In a section referring to contingency measures, 
Ecology describes, and ascribes emission reduction estimates to 
measures to demonstrate maintenance through 1994. However, these 
measures are being relied on to demonstrate maintenance and therefore 
cannot be approved as meeting the contingency measure requirements of 
section 172. Since the action proposed in this Federal Register 
document is related to elements of the SIP due on November 15, 1991, 
EPA will not otherwise address the contingency measure requirement at 
this time.

III. Implications of This Action

    EPA conditionally approves the plan revisions submitted to EPA for 
the Seattle, Washington, nonattainment area on November 5, 1990; 
December 27, 1990; November 15, 1991; and May 11, 1994. EPA approves 
the control measures contained in the plan submissions because they 
strengthen the plan by further limiting PM-10 emissions in the area. 
EPA also grants an exclusion from precursor control requirements as 
described in part II. 5 of this document. EPA will assess the 
approvability of these submittals after the State fulfills its 
commitment. If the State fails to comply with its commitment, the 
conditional approval will become a disapproval.
    As noted, additional submittals for the initial moderate PM-10 
nonattainment areas are due at dates after the November 15, 1991, 
deadline. EPA will determine the adequacy of any such submittals as 
appropriate and take action at a later date.

IV. Administrative Review

    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 2214-2224), as revised by an October 4, 1993, 
memorandum from Michael H. Shapiro, Acting Assistant Administrator for 
Air and Radiation. A future document will inform the general public of 
these tables. On January 6, 1989, the Office of Management and Budget 
(OMB) waived Table 2 and Table 3 SIP revisions (54 FR 2222) from the 
requirements of section 3 of Executive Order 12291 for two years. The 
EPA has submitted a request for a permanent waiver for Table 2 and 
Table 3 SIP revisions. The OMB has agreed to continue the waiver until 
such time as it rules on EPA's request. This request continues in 
effect under Executive Order 12866 which superseded Executive Order 
12291 on September 30, 1993.
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States of 
Appeals for the appropriate circuit by August 22, 1994. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this rule for the purposes of judicial 
review nor does it extend the time within which a petition for judicial 
review may be filed and shall not postpone the effectiveness of such 
rule or action. This action may not be challenged later in proceedings 
to enforce its requirements. (See section 307(b)(2), 42 U.S.C. 
7607(b)(2).
    The EPA is publishing this action without prior proposal because 
the Agency views this as a noncontroversial amendment and anticipates 
no adverse comments. This action will be effective August 22, 1994, 
unless adverse comments are received by July 25, 1994. If the EPA 
receives adverse comments, the direct final rule will be withdrawn and 
all public comments received will be addressed in a subsequent final 
rule based on the proposed rule (please see short informational notice 
published, simultaneously, in the proposal section of this Federal 
Register).
    Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA 
must prepare a regulatory flexibility analysis assessing the impact of 
any proposed or final rule on small entities. 5 U.S.C 603 and 604. 
Alternatively, EPA may certify that the rule will not have a 
significant economic impact on a substantial number of small entities. 
Small entities include small businesses, small not-for-profit 
enterprises, and government entities with jurisdiction over populations 
of less than 50,000.
    SIP approvals under section 110 and subchapter I, part D of the CAA 
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 CAA, 
preparation of a regulatory flexibility analysis would constitute 
Federal inquiry into the economic reasonableness of state action. The 
CAA forbids EPA to base its actions concerning SIPs on such grounds. 
Union Electric Co. v. U.S. E.P.A. , 427 U.S. 246, 256-66 (S.Ct. 1976); 
42 U.S.C. 7410(a)(2).
    Nothing in this action should be construed as permitting or 
allowing or establishing a precedent for any future request for 
revision to any state implementation plan. Each request for revision to 
the state implementation plan shall be considered separately in light 
of specific technical, economic and environmental factors and in 
relation to relevant statutory and regulatory requirements.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Hydrocarbons, Incorporation by reference, Particulate matter, Ozone, 
Volatile organic compounds.

    Note: Incorporation by reference of the implementation plan for 
the State of Washington was approved by the Director of the Office 
of Federal Register on July 1, 1982.

    Dated: May 27, 1994.
Chuck Clarke,
Regional Administrator.

    Part 52, chapter I, title 40 of the Code of Federal Regulations is 
amended as follows:

PART 52--[AMENDED]

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

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

Subpart WW--Washington

    2. Section 52.2470 is amended by adding paragraph (c) (47) to read 
as follows:


Sec. 52.2470  Identification of plan.

* * * * *
    (c) * * *
    (47) On November 5, 1990, December 27, 1990, November 15, 1991 and 
May 11, 1994 the Director of WDOE submitted to EPA SIP revisions for 
the purpose of bringing about attainment of the National ambient air 
quality standards (NAAQS) for particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers (PM-10). The 
implementation plan was submitted by the State to satisfy certain 
Federal Clean Air Act requirements for an approvable moderate 
nonattainment area PM-10 SIP for Seattle, Washington.
    (i) Incorporation by reference.
    (A) Letters dated November 5, 1990, December 27, 1990, November 13, 
1991 and May 2, 1994, from WDOE to EPA submitting the revisions to the 
SIP for the State of Washington.
    (B) Revisions to the Washington SIP for the purpose of bringing 
about attainment of the National ambient air quality standards (NAAQS) 
for particulate matter with an aerodynamic diameter less than or equal 
to a nominal 10 micrometers (PM-10):
    (1) A Plan for Attaining and Maintaining the National Ambient Air 
Quality Standard for PM-10 in the Seattle Duwamish Valley, September 
1989, adopted November 3, 1990;
    (2) Resolution No. 639 (amendments to the PM-10 attainment and 
maintenance strategy), adopted December 8, 1988;
    (3) State Implementation Plan for Particulate Matter in the Seattle 
Duwamish Valley, Supplement, dated November 199l, adopted November 14, 
1991; and
    (4) State Implementation Plan for Particulate Matter in the Seattle 
Duwamish Valley, Supplement, dated January 1, 1994, adopted May 4, 
1994.
[FR Doc. 94-15260 Filed 6-22-94; 8:45 am]
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