Approval and Promulgation of Implementation Plans: Washington

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[WA5-1-5539a, WA27-1-6612a; FRL-5078-9]

Approval and Promulgation of Implementation Plans: Washington

AGENCY: Environmental Protection Agency.

ACTION: Direct final rule.

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SUMMARY: Environmental Protection Agency (EPA) conditionally approves a

revision to the State implementation plan (SIP) submitted by the State

of Washington for the purpose of bringing about the 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 requirements for an approvable moderate

nonattainment area PM-10 SIP for Tacoma, Washington.

DATES: This final rule will be effective on December 12, 1994 unless

adverse or critical comments are received by November 14, 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, Environmental Protection Agency, Air and Radiation 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, Environmental Protection Agency, 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, Region 10, Air &

Radiation Branch, 1200 Sixth Avenue (AT-082), Seattle, Washington

98101, and the State of Washington Department of Ecology, 4450 Third

Avenue SE., Lacey, Washington 98504.

FOR FURTHER INFORMATION CONTACT: Claire Hong, Air and Radiation Branch

(AT-082), Environmental Protection Agency, 1200 Sixth Avenue, Seattle,

Washington 98101, (206) 553-1813.

SUPPLEMENTARY INFORMATION:

I. Background

The Tacoma, 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 (CAA), upon enactment of the Clean Air Act Amendments

(CAAA) of 1990.1 See 56 FR 56694 (November 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 EPA has issued a

``General Preamble'' describing EPA's preliminary views on how EPA

intends to review SIPs and SIP revisions submitted under Title I of the

Act, including those State submittals containing moderate PM-10

nonattainment area SIP 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 this notice and the supporting

rationale. In this rulemaking action on the State of Washington's

moderate PM-10 SIP for the Tacoma nonattainment area (referred to as

Tacoma or the Tacoma Tideflats), EPA is applying 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. Those

States containing initial moderate PM-10 nonattainment areas (those

areas designated nonattainment under CAA section 107(d)(4)(B)) were

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

November 15, 1991:

\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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1. Provisions to ensure 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 three

years and which demonstrate reasonable further progress (RFP) toward

attainment by December 31, 1994; and

4. Provisions to ensure 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).

Additional 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 CAA section 189(a)).

The Washington State Department of Ecology (WDOE) submitted the new

source review requirements for this area on October 22, 1993. EPA will

address that submittal in a separate Federal Register document.

Such States also were required 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 CAA section 172(c)(9) and 57 FR 13510-13512 and 13543-

13544). EPA addresses the contingency measures the State has submitted

for Tacoma in part II.8 of the discussion below.

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. If the

conditional approval is converted to a disapproval, the sanctions clock

under section 179 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 Tacoma, Washington, on November 15, 1991

and June 30, 1994 (hereafter generally referred to as a single

submittal), except for the following elements of the SIP which are

described below or in the Technical Support Document associated with

this rulemaking. EPA is approving these following elements without

conditions: exclusion from precursor controls, the monitoring network,

the procedures for consultation and public notification, the provisions

for revising the plan and the adequacy of funding and authority.

EPA conditionally approves the submittal because it does not fully

meet certain applicable requirements of the CAA for moderate PM-10

nonattainment areas. The submittal does not meet the requirements to

provide for the implementation of RACM (including RACT), to demonstrate

timely attainment of the PM-10 NAAQS (or demonstrate that timely

attainment is not practicable), and to provide for quantitative

milestones and reasonable further progress. See CAA sections 172(c)(1),

189(a)(1)(C), 189(a)(1)(B) and 189(c). Some of the control measures

relied on to satisfy these requirements have not been made enforceable

emission limitations. CAA sections 110(a)(2)(A) and 172(c)(6). However,

the State has submitted a commitment to adopt specific enforceable

measures on or before January 1, 1995, and to address the applicable

requirements of the Act. In its June 30, 1994 SIP revision, the State

committed to submitting federally enforceable emission limits to EPA by

January 1, 1995 for the following major stationary sources identified

in the SIP: Buffelen Woodworking, Continental Grain, Continental Lime,

Domtar Gypsum, Puget Sound Plywood, USG Interiors, US Oil and Refining,

Woodworth, Kaiser Aluminum and Chemical Corporation and Simpson Tacoma

Kraft Company.

The submittal is substantive and contains some specific enforceable

control measures. Accordingly, EPA is conditionally approving the

submittal, as authorized under section 110(k)(4) of the CAA. EPA also

approves, without conditions, the separable exclusion from precursor

controls as described in part II.5 below, the monitoring network, the

procedures for consultation and public notification, the provisions for

revising the plan and the adequacy of funding and authority.

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.

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\3\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 CAA 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. 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 Washington Department of Ecology conducted a public

hearing to receive public comment on the State implementation plan

revision for PM-10 in Tacoma on November 7, 1991. WDOE adopted the

implementation plan for the area on November 15, 1991, and submitted it

to EPA the same day. In 1994, the plan was revised to amend its request

for conditional approval. WDOE conducted a public hearing to obtain

public input on this revision on February 17, 1994. The letter revising

the request for conditional approval was submitted to EPA on June 30,

1994. The November 15, 1991 and June 30, 1994 SIP submittals were

reviewed by EPA to determine completeness in accordance with the

completeness criteria set out at 40 CFR part 51, appendix V. Letters

dated May 12, 1992 and August 1, 1994, were forwarded to the WDOE

indicating the completeness of the submittals 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 and current inventory of

actual emissions from all sources of relevant pollutants in the

nonattainment area. The emissions inventory should also include a

comprehensive, accurate and current inventory of allowable emissions in

the area. See, e.g., CAA section 110(a)(2)(K). Because the submission

of 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 attainment/

nonattainment demonstration submission (see 57 FR 13539).

WDOE submitted an emissions inventory of estimated actual emissions

for the base year of 1987 and the attainment year of 1994. The 24-hour

emission inventory identified three major source categories

contributing to particulate matter in the Tacoma Tideflats. These are,

in descending order of greatest contribution, industrial stack

emissions (66 percent); vehicle resuspended road dust (18 percent); and

industrial fugitive emissions (13 percent). Other contributing sources

were area sources, such as residential wood combustion and motor

vehicle exhaust. The emission inventory is dominated by one point

source, the Simpson Tacoma Kraft Company (Simpson), a paper pulp

producer, which accounts for 45 percent of the emission inventory.

For sources within the nonattainment area, the emissions inventory

provides a comprehensive list of particulate sources and utilizes

appropriate factor and estimations that were available at the time the

SIP revision was prepared. However, the emission inventory may

underestimate the impact of PM-10 sources outside of the nonattainment

area. Possibly due to where the nonattainment area boundaries were

drawn, there may be a significant source of PM-10 outside of the

nonattainment area. As is discussed in the Technical Support Document

(TSD), substantial evidence indicates that imported residential wood

combustion accounts for a large portion of the PM-10 in the Tacoma

Tideflats. For further information, the reader is referred to the TSD

accompanying this action, which is available at the EPA address

indicated above.

The emissions inventory estimating actual emissions along with

additional available information 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 additional 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

more detail under the demonstration section of this document. Again,

the reader is referred to the TSD corresponding with this action for

further information.

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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. See CAA section 193.

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3. RACM (Including RACT)

As noted, the initial moderate PM-10 nonattainment areas must

submit provisions to ensure that RACM (including RACT) are implemented

no later than December 10, 1993 (see CAA 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).

In broad terms, the State should identify available control

measures evaluating them for their reasonableness in light of the

feasibility of the controls and the attainment needs of the area. A

State may reject available control measures if the measures are

technologically infeasible or the cost of the control is unreasonable.

In addition, RACM, does not require controls on emissions from sources

that are insignificant (i.e. de minimis) and RACM does not require the

implementation of all available control measures where an area

demonstrates timely attainment of the NAAQS and the implementation of

additional controls would not expedite attainment. 57 FR 13540-13544.

Washington's control strategy for the Tacoma area provides for

attainment of the 24-hour standard based on control of industrial

emissions, fugitive industrial emissions including resuspended road

dust, and residential wood combustion. However, as indicated below,

some of the control measures are deficient because they are not

reflected in enforceable emission limitations. See CAA sections

110(a)(2)(A) & 172(c)(6). The State has committed to address this

deficiency and, based on section 110(k)(4) of the CAA, EPA is

conditionally approving the submittal relative to the RACM (Including

RACT) requirement. The available control measures to be implemented in

Tacoma include the following:

a. Industrial Controls

The largest single reduction in the projected emission inventory

results from the control of industrial stack emissions. As stated

earlier, Simpson accounts for 45 percent of the emission inventory. In

1991, Simpson replaced the #2,3,4,5 hogged fuel boilers and #1 oil

boiler at the mill with a new hogged fuel boiler. Emissions from the

new boiler represent a 984 kg/day reduction in emissions, almost half

of Simpson's previous emissions, or roughly 19 percent of the total

baseline emissions inventory.

In addition, changes in industrial processes resulted in decreased

emissions; for example, U.S. Oil and Refining and Simpson changed fuel

sources to burn natural gas. The SIP assumes that emissions from mobile

sources will grow modestly from 1987 to 1994. Even including these

growth projections, the overall reduction in industrial PM-10 stack

emissions due to implementation of controls for all sources combined is

projected to be 17 percent of the base year's inventory. However, these

industrial changes and controls have not been expressed as enforceable

emission limitations. As discussed earlier, WDOE has committed to

submit enforceable emissions limits on the industrial sources by

January 1, 1995.

b. Industrial Fugitive and Resuspended Road Dust

The Tacoma emission inventory identified industrial fugitive

emissions and resuspended road dust as significant contributors of

particulate matter to the airshed. The Puget Sound Air Pollution

Control Agency (PSAPCA) is a local air pollution control agency that

has jurisdiction over four counties in Washington State; PSAPCA's

jurisdiction includes the Tacoma Tideflats. 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 Tacoma

attainment plan lists and documents emission reductions from several

major facilities that were required to pave roads or add PM-10 controls

as the result of PSAPCA's application of section 9.15. Puget Sound

Plywood, Lone Star, Woodworth and Buffelen were required to either pave

roads or modify production processes to comply with section 9.15. The

SIP estimates that the application of section 9.15 would result in a

reduction of 73 kg/day of fugitive emissions from industrial sources.

After accounting for an increase of 39 kg/day due to industrial growth,

the net total reduction from the base year to the attainment year of

fugitive emissions is 34 kg/day. 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.

Control of resuspended road dust is a significant component of

section 9.15. 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 Tacoma nonattainment area are required to implement BACT to

stabilize vehicular entrances and exits. The control measure also

appropriately prioritized preventing material deposition on roadways

over mitigating measures after deposition. Looking specifically at the

control of resuspended road dust, the plan uses an overall emission

reduction credit of 37 percent from resuspended road dust. EPA accepts

this estimate as reasonable.

c. Residential Wood Combustion

As previously noted, there is a substantial body of evidence

indicating that imported residential wood combustion is a large source

of Tacoma's PM-10. All three receptor models concluded that woodsmoke

was one of the main sources of particulate matter in the Tacoma

Tideflats area. The most recent receptor modeling study suggested that

residential wood combustion was an unexpectedly strong source of PM-10.

This is also supported by the Saturation Study conducted by EPA.

Additional discussion of the impact of imported residential wood

combustion can be found in the TSD associated with this action. Because

of the likely impact of imported residential wood combustion on

Tacoma's airshed, the available control measures adopted for

residential wood combustion are discussed here.

PSAPCA initiated a voluntary woodsmoke curtailment program

throughout its four county jurisdictional area, including Tacoma, 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 woodheating (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 percent, with brief exceedances allowed for fire starting

and stoking. PSAPCA serves as the primary enforcement agency for the

curtailment and opacity portions of the control program. Both WDOE and

PSAPCA 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 Tacoma area is achieving a

sufficient compliance rate to justify the 70 percent emission reduction

credit taken for these measures. A more detailed analysis of the

Washington woodsmoke curtailment plan is contained in the TSD. Since

PSAPCA administers the woodsmoke curtailment program throughout its

four-county jurisdictional area and the program affects sources both

within the nonattainment area and in adjoining areas, the 70 percent

emission reduction credit is applicable to both residential wood

combustion generated in the nonattainment area and imported residential

wood combustion.

As indicated, where sources of PM-10 contribute insignificantly to

the PM-10 problem in the area, EPA's policy is that RACM does not

require the implementation of potentially available control measures.

57 FR 13540. Further, EPA has indicated that for some sources in areas

which demonstrate timely 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 Tacoma 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 that RACM does not require the implementation of

potentially available control measures or technology for other de

minimis sources of PM-10 in the area. 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. However, as addressed in more detail in

part II.4 below, not all of the emission reductions necessary to ensure

expeditious attainment of the PM-10 NAAQS are embodied in enforceable

emission limitations. Thus, EPA is conditionally approving the control

measures submitted for Tacoma, based upon a commitment by the State

that it will submit to EPA by January 1, 1995, legally enforceable

emission limits for the significant stack sources in Tacoma. See CAA

section 110(k)(4). 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 (CAA section 189(a)(1)(B)(ii)).

Several studies have been conducted to determine sources of

particulate matter in the Tacoma nonattainment area. WDOE and PSAPCA

employed pollutant dispersion models in the Tacoma nonattainment area

using both guideline and non-guideline models. Neither RAM (guideline)

nor WYNDvalley (non-guideline) yielded results that were well

correlated to measured values. It is difficult to determine precisely

why dispersion modeling failed to yield acceptable values in the Tacoma

Tideflats when similar approaches have proven successful elsewhere, but

the TSD raises possible explanations, including where the boundaries of

the nonattainment were drawn and how the background PM-10 concentration

was established. The reader is referred to the ``Description of Air

Quality Modeling'' section of the TSD associated with this action for

further information.

In addition to dispersion modeling, three receptor modeling studies

were conducted in the Tacoma Tideflats to try to determine source

contribution of PM-10. Separate from these receptor modeling studies, a

saturation study was conducted to determine the site of maximum impact

in the Tacoma nonattainment area. Unfortunately, no single study

conclusively apportions the amount of PM-10 attributable to different

sources. As is discussed in the TSD, EPA has reservations about each of

these studies because of study design flaws, errors in conducting the

study, or changing composition of particulate matter in the airshed.

See the ``Attainment Demonstration'' section of the TSD for a longer

discussion of the individual studies.

Faced with several studies, none of which were definitive, the WDOE

attempted to address several diverse scenarios to demonstrate

attainment and maintenance of the PM-10 NAAQS in the area. The SIP

contains three demonstrations of attainment and maintenance all using

rollback, a modified attainment demonstration that EPA may accept on a

case-by-case basis. The first demonstration presented in the SIP is

based on receptor modeling and proportional rollback; the second used a

dispersion modeling study and proportional rollback; and the last was

based on straight rollback. Tacoma's SIP meets the criteria for using

rollback as outlined in EPA guidance (Attachment 5 of''PM-10 Moderate

Area SIP Guidance: Final Staff Work Product,'' April 2, 1990). EPA's

primary concern about the demonstrations in the SIP is that they

underestimate the amount of PM-10 from residential wood combustion

coming into the nonattainment area from surrounding areas.

As discussed in the TSD, EPA believes that when looking at the

receptor modeling and saturation studies as a whole, there is a

substantial body of evidence indicating that residential wood

combustion was and is a major source of PM-10 in the airshed. As

discussed in the TSD, this residential wood combustion is probably

being imported into the nonattainment area, and a conservative lower

bound estimate is that 35-45 percent of the PM-10 in the Tacoma

Tideflats on the design day is attributable to residential wood

combustion. A more detailed discussion of this point can be found in

the ``Attainment Demonstration'' of the TSD.

EPA notes that there has been uncertainty over source contribution

in the Tacoma nonattainment area despite numerous efforts by PSAPCA,

WDOE, EPA and other entities to characterize the airshed. In reviewing

the SIP, EPA has considered all relevant studies referenced in the SIP

as well as additional information, such as the saturation study. Based

on these studies, EPA finds that imported residential wood combustion

is a much larger source of PM-10 than currently accounted for in the

SIP.

To evaluate the impact of imported residential wood combustion into

the nonattainment area, the TSD associated with the rulemaking contains

a rollback analysis that incorporates a relatively conservative

estimate of the residential wood combustion being imported into the

nonattainment area. As noted earlier, Tacoma's SIP meets the criteria

for using rollback. In the ``Attainment Demonstration'' discussion of

the TSD, EPA sets out a rollback scenario that incorporates the

estimate that 35-45 percent of the PM-10 in the Tacoma Tideflats on the

design day is attributable to residential wood combustion. A mandatory

residential woodsmoke curtailment program is being imposed over a four-

county area that includes the Tacoma Tideflats and surrounding

contiguous areas. As discussed earlier in section II.3 of this

document, PSAPCA's mandatory woodstove curtailment program warrants a

70 percent control measure credit. After applying control measure

credit for the mandatory woodstove curtailment program, the rollback

scenario presented in the TSD demonstrates; to EPA's satisfaction, that

the PM-10 NAAQS will be attained by 1994.

Assurance of attainment and maintenance rests with the SIP's

control measures. The SIP contains a broad array of control measures

aimed at both industrial and residential sources. Based on the emission

inventory and related information about the estimated contribution from

residential wood combustion, these control measures, when they are made

fully enforceable (see below), will be sufficient to ensure attainment

and maintenance.

It should be noted that 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 CAA sections 110(a)(2)(A),

110(a)(2)(K) and 172(c)(6) of the Act). The requirement takes into

consideration possible increases from existing sources allowed by their

permits, registrations, or other regulatory mechanisms and ensures that

the control measures relied on in the SIP are based on enforceable

emission limitations. WDOE 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, to ensure that the NAAQS will be

protected in the Tacoma nonattainment area, the currently allowable

emission limits must be reduced.

Despite the fact that Tacoma has been monitoring daily at the site

determined to be the site of maximum impact and has not had an

exceedance of the NAAQS at any monitor in four years, there are no

legal limits in place to prevent future increases from a few industrial

facilities that could consequently threaten attainment of the NAAQS. On

June 30, 1994, WDOE submitted a request for conditional approval of the

Tacoma nonattainment plan based on a commitment to reconcile the

actual/allowable emission limitation issue and thereby establish an

enforceable attainment demonstration. WDOE's commitment includes a

schedule to issue regulatory orders to appropriate point sources within

the nonattainment area that will restrict emissions (i.e. establish

allowable emission limitations) at or below the ``actual'' emission

estimates used in the attainment demonstration. EPA conditionally

approves the attainment demonstration for Tacoma on the basis of this

commitment. See CAA section 110(k)(4). The revisions to the emission

limitations for the affected sources will make enforceable the actual

emission limitations already being achieved and implemented in the

area.

Like the attainment demonstration, Tacoma's SIP contained three

maintenance demonstrations. The first demonstration is based on

receptor modeling and proportional rollback; the second used a

dispersion modeling study and proportional rollback; and the last was

based on straight rollback; however, the last demonstration failed to

show maintenance through 1997. EPA believes that the failure of the

third demonstration to show maintenance through 1997 is due to the

SIP's low estimate of imported residential woodsmoke.

In the ``Evaluation of Attainment Demonstration'' section of the

accompanying TSD, EPA considered additional information and analyses in

assessing the maintenance demonstration, including using rollback that

differs from the SIP in its estimate of the amount of residential wood

combustion affecting the airshed. EPA believes that after evaluating

all of the studies of the Tacoma Tideflats, there is sufficient

evidence to support an interpretation that imported residential wood

combustion is a much stronger source of PM-10 than currently accounted

for in the SIP. Similar to the demonstration of attainment presented in

the ``Attainment Demonstration'' of the TSD, EPA believes a greater

background value that accounts for a large importation of residential

woodsmoke should be employed in the maintenance demonstration. Using

the emission inventory, growth factors, and point source emission

levels presented in the SIP, considering additional information about

the contribution of residential wood combustion and employing the same

background value as was used in the attainment demonstration discussed

in the TSD, the rollback analysis demonstrates maintenance through

1997, and would therefore satisfy the initial quantitative milestones

due for this area, as discussed in part II.6 below. However, as with

the attainment demonstration, some of the control measures relied on to

demonstrate continued maintenance of the PM-10 NAAQS in the SIP are

deficient because they are not reflected in enforceable emission

limitations. See CAA sections 110(a)(2)(A) & 172(c)(6). The State has

committed to address this deficiency and, based on section 110(k)(4) of

the CAA, EPA is conditionally approving the submittal relative to the

quantitative milestone and reasonable further progress requirements

discussed below.

The accompanying TSD discusses the dispersion, receptor and

saturation studies conducted in the Tacoma Tideflats, estimates the

amount of PM-10 attributable to residential wood combustion, and

presents a rollback demonstration for attainment and maintenance that

incorporates the estimate that 35-45 percent of the PM-10 in the Tacoma

Tideflats on the design day is attributable to residential wood

combustion. The reader is referred to the TSD associated with this

document for a more detailed discussion of any of these points.

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) of the Act (see

57 FR 13539-13540 and 13541-13542).

The three receptor modeling studies conducted in the Tacoma

Tideflats show that sulfates and nitrates are not a significant portion

of the Tacoma PM-10 in the airshed. The three studies are discussed in

the TSD. The two receptor modeling studies conducted during the 1980s

show that nitrates accounted for less than 4 percent of the total PM-10

sampled mass, while sulfates contributed even less measuring less than

2.5 percent.

The third receptor modeling study, the Evaluation of the

Atmospheric Deposition of Toxic Contaminants to Puget Sound study was

conducted in the Tacoma Tideflats during 1989 and 1990. The Atmospheric

Deposition Study collected fine particulate ( 2.5

m) and coarse particulate ( 50 m). Most of

the precursor particles would be occurring in the fine particle range.

The analysis of the fine particles showed that SO4 was 9.3 percent

of the total mass of fine particles, while NO3 accounted for

approximately 5 percent of total mass of fine particles. As discussed

in the ``Evaluation of Attainment Demonstration'' in the accompanying

TSD, the Atmospheric Deposition Study was conducted during a period

when the airshed was considerably cleaner than the design year.

Moreover, control measures were in place during the Atmospheric

Deposition Study's sampling period; five of the sampling days occurred

during a ban on the use of uncertified woodstoves. Therefore, the

results of this study are likely to show less PM-10 due to woodsmoke

than probably occurred during the design year. Correspondingly, the

study's assessment of the amount of SO4 and NO3 found in the

airshed is likely to be greater on a percentage basis than would have

been the case during the design year.

Due to the relatively small amount of sulfates and nitrates in the

airshed, EPA has determined that it is unlikely that precursors do not

contribute significantly to PM-10 levels which exceed the NAAQS in

Tacoma. In addition to these receptor analyses, a review of the

emissions inventory for this area did not reveal any major stationary

sources of PM-10 precursors. The effect of this finding is to exclude

major stationary sources of PM-10 precursors from PM-10 nonattainment

area control requirements.

While EPA is making a general finding about the contribution of PM-

10 precursors for Tacoma, the determination is based on the current

character of the area including the existing mix of sources in the

area. It is possible, therefore, that future growth could change the

significance of precursors in the area. The 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 CAA 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.

While section 189(c) plainly provides that quantitative milestones

are to be achieved until an area is redesignated attainment, it is

silent in indicating the starting point for counting the first 3-year

period or how many milestones must be initially addressed. In the

General Preamble, EPA addressed the statutory gap in the starting point

for counting the 3-year milestones, indicating that it would begin from

the due date for the applicable implementation plan revision containing

the control measures for the area (i.e., November 15, 1991 for initial

moderate PM-10 nonattainment areas). See 57 FR 13539. As to the number

of milestones, EPA believes that at least two milestones must be

initially addressed. Thus, submittals to address the SIP revisions due

on November 15, 1991 for the initial moderate PM-10 nonattainment areas

must demonstrate timely attainment of the PM-10 NAAQS, the second

milestone should, at a minimum, provide for continued maintenance of

the standards.5

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\5\ Section 189(c) provides that quantitative milestones are to

be achieved ``until the area is redesignated attainment.'' However,

this endpoint for quantitative milestones is speculative because

redesignation of an area as attainment is contingent upon several

factors and future events.

EPA believes it is unreasonable to require planning for each

nonattainment area to cover quantitative milestones years into the

future because of the possibility that such time may elapse before

an area is in fact redesignated attainment. On the other hand, EPA

believes it is reasonable for States initially to submit a

sufficient number of milestones to ensure that there is continuing

air quality protection beyond the attainment deadline. Addressing

two milestones will ensure that the State continues to maintain the

NAAQS beyond the attainment date for at least some period during

which an area could be redesignated attainment. However, in all

instances, additional milestones must be addressed if an area is not

redesignated attainment within the time period covered by the

initial milestones.

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In implementing RFP for this initial moderate area, EPA has

reviewed the attainment demonstration and control strategy for the area

to assess whether the initial milestones have been satisfied and 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 CAA section 171(1)). As

indicated, the State of Washington's PM-10 SIP for Tacoma demonstrates

attainment in 1994 and maintenance through 1997, and therefore would

satisfy RFP and initial quantitative milestones (see 57 FR 13539) if

all of the control measures relied upon were reflected in enforceable

emission limitations. However, as discussed previously, WDOE 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. CAA

section 110(k)(4).

7. Enforceability Issues

All measures and other elements in the SIP must be enforceable by

WDOE and EPA (see CAA 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 CAA 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.

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.

Both WDOE and PSAPCA have responsibilities in the implementation

and enforcement of control measures in the Tacoma nonattainment area.

PSAPCA retains authority over all area sources and all but the two

stationary sources in Tacoma that are regulated by the Department of

Ecology. PSAPCA has many compliance inspectors and, as discussed

further in the TSD, EPA considers PSAPCA's staffing level adequate to

ensure that the Tacoma 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, assess penalties,

require access to records and information, and receive and disburse

funds. The Washington State Department of Ecology has adequate

authority to implement and enforce the plan in the event PSAPCA fails

to make a good faith effort to implement and/or enforce the

regulations.

The two point sources in the Tacoma nonattainment area not under

PSAPCA's jurisdiction are the Simpson Tacoma Kraft Company and Kaiser

Aluminum and Chemical Corporation. These sources are regulated by the

Washington State Department of Ecology. The Washington State Department

of Ecology's legal authorities, personnel and funding sources are

discussed in the accompanying TSD. EPA finds these authorities and

funding mechanisms adequate to ensure that the State will be able to

enforce the control measures in the Tacoma nonattainment area.

Controls on area sources, such as the residential wood combustion

program and the fugitive dust control program are also 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 WDOE or PSAPCA regulations is unacceptable.

WDOE, PSAPCA, and EPA could only enforce the allowable emissions that

are currently contained in the WDOE or PSAPCA regulations. There are no

mechanisms for any of the regulatory agencies to enforce the emission

estimates used in the attainment and maintenance demonstration because

they are well below the legal limits allowed in the WDOE or PSAPCA

regulations.

A discussion regarding the use of actual instead of allowable

emissions contained in the demonstration portion of this document

provides background for the enforceability decision. The Region is

granting a conditional approval of the Tacoma attainment plan based on

the commitment contained in the June 30, 1994, submittal which will

make the emissions from point sources enforceable at or below the

levels used to demonstrate attainment and maintenance. EPA will need

additional technical documentation from WDOE if the emission levels in

the regulatory orders are greater than those used in the attainment and

three year maintenance demonstrations. Additionally, WDOE would need to

provide cogent attainment and maintenance demonstrations in order for

the SIP to be fully approved.

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 13510-13512 & 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 core 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.

Assessing the adequacy of Tacoma's contingency measures is tied to

the attainment demonstration because Tacoma has submitted industrial

emissions controls in excess of those needed to demonstrate timely

attainment of the PM-10 NAAQS as a contingency measure. As discussed

above, Simpson's boiler replacement alone represents a 984 kg/day

reduction in emissions, almost half of Simpson's previous emissions, or

roughly 19 percent of the total baseline emissions inventory. Based on

the rollback discussion provided in the accompanying TSD, the Tacoma

SIP contains emissions limits and contingency measures that provide for

reductions greater than the 25 percent contingency measure emissions

reduction value suggested in the General Preamble (57 FR 13543-13544).

Further discussion can be found in the ``Contingency Measure'' section

of the accompanying TSD.

The contingency measures submitted as part of the Tacoma SIP ranged

from a commitment to implement mobile source controls to crediting the

emission limitations already existing in the SIP that would be in

excess of those needed to address the RACM (including RACT)

requirement. The two mobile source contingency measures in the 1991 SIP

were directed at reducing emissions from diesel vehicles: (1) the

establishment of an inspection and maintenance (I/M) program, and (2)

the reduction in sulfur content of on-highway diesel fuel. In 1993,

Washington State expanded its I/M program to include the Tacoma area,

and the desulfurization program was implemented nationally.

Only the measures that are being implemented prior to a

determination that the area has failed to timely attain or achieve RFP,

that would be in excess of those necessary to provide for timely

attainment of the PM-10 NAAQS and that, therefore, go beyond RACM

(including RACT) can be relied on as contingency measures. The measures

will provide for continued emissions reduction progress beyond the core

control strategy. Further, because the State would implement these

precautionary measures prior to a determination that the area has

failed to timely attain the NAAQS or achieve RFP, these measures

essentially provide advance contingency benefit and satisfy the

requirement that they ``take effect . . . without further action by the

State, or the Administrator.'' EPA believes it would be unreasonable to

penalize or otherwise discourage the State from taking the arguably

more precautionary air quality management step of accelerating the

implementation of these contingency measures.

However, it cannot be determined whether these measures are in

excess of those necessary to provide for expeditious attainment and

necessary to address RACM (including RACT) until the State addresses

the deficiencies associated with its core control strategy. As

indicated elsewhere, the State has committed to convert measures

necessary to address RACM (including RACT) to enforceable emission

limitations. Until this commitment is fulfilled, EPA cannot conclude

that the contingency measures go beyond the core control strategy.

Therefore, EPA is conditionally approving these contingency

measures. Due to the submission of emission reductions that are

purportedly in excess of those necessary to demonstrate timely

attainment and necessary to satisfy RACM as a contingency measure,

final approval or disapproval of these contingency measures must be

determined when WDOE submits the regulatory orders establishing

enforceable emission limits for the stationary sources in the Tacoma

Tideflats.

III. Implications of This Action

EPA conditionally approves the plan revisions submitted to EPA for

the Tacoma, Washington, nonattainment area on November 15, 1991, and

June 30, 1994, except for the following elements which EPA approves in

full. EPA also approves, without conditions, the separable exclusion

from precursor controls as described in part II.5 above, the monitoring

network, the procedures for consultation and public notification, the

provisions for revising the plan and the adequacy of funding and

authority. EPA will assess the final approvability of the submittals

EPA is conditionally approving after the State fulfills its commitment

to submit enforceable emission limitations by January 1, 1995. If the

State fails to comply with its commitment, the conditional approval

will become a disapproval.

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. OMB has exempted this regulatory action from

Executive Order 12866 review.

Under section 307(b)(1) of the Clean Air Act, petitions for

judicial review of this action must be filed in the United States Court

of Appeals for the appropriate circuit by December 12, 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 CAA 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 on December 12, 1994

unless adverse comments are received by November 14, 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 the proposed rule

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.

Conditional approvals of SIP submittals 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, EPA certifies 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).

If the conditional approval is converted to a disapproval under

section 110(k), based on the State's failure to meet the commitment, it

will not affect any existing State requirements applicable to small

entities. Federal disapproval of the State submittal does not affect

its State-enforceability. Moreover, EPA's disapproval of the submittal

does not impose a new Federal requirement. Therefore, EPA certifies

that this disapproval action does not have a significant impact on a

substantial number of small entities because it does not remove

existing State requirements nor does it substitute a new Federal

requirement.

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, Incorporation by

reference, Intergovernmental relations, Particulate matter, Reporting

and recordkeeping requirements.

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: September 20, 1994.

Gerald A. Emison,

Acting 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)(48) to read

as follows:

Sec. 52.2470 Identification of plan.

* * * * *

(c) * * *

(48) On November 15, 1991, the Director of WDOE submitted to EPA a

PM-10 nonattainment area SIP revision 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 Tacoma,

Washington.

(i) Incorporation by reference.

(A) Letters dated November 13, 1991 and June 30, 1994 from WDOE to

EPA submitting revisions to the State of Washington SIP.

(B) State Implementation Plan for Particulate Matter in the Tacoma

Tideflats, Pierce County, including appendices A-F, dated November

1991, and adopted November 14, 1991.

[FR Doc. 94-25204 Filed 10-11-94; 8:45 am]

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