Approval and Promulgation of State Implementation Plans: Idaho

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[ID 1-1-5528; FRL-5076-9]

Approval and Promulgation of State Implementation Plans: Idaho

AGENCY: Environmental Protection Agency.

ACTION: Notice of proposed rulemaking.

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SUMMARY: The Environmental Protection Agency (EPA) proposes to take

action on the state implementation plan (SIP) submitted by the State of

Idaho Division of Environmental Quality (State or IDEQ) 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) in the Ada

County/Boise area. The SIP was submitted by the State to satisfy

certain Federal requirements for an approvable moderate nonattainment

area PM-10 SIP for Ada County/Boise, Idaho.

In summary, EPA proposes to grant full approval of the emissions

inventory and PM-10 precursor exclusion elements of the SIP because

they are separable and independent elements. EPA proposes limited

approval under sections 110(k)(3) and 301(a) of the Clean Air Act (CAA)

of the control measures that have been submitted by the State to date.

This limited approval of the control measures is for the limited

purpose of making them federally enforceable and thereby advancing the

Clean Air Act NAAQS-related air quality goals. At the same time, EPA is

proposing to disapprove the control measures as not satisfying the

specific requirement under sections 172(c)(1) and 189(a)(1)(C) of the

CAA to submit a SIP revision that includes provisions to assure that

reasonably available control measures (RACM) are implemented no later

than December 10, 1993 and to disapprove the attainment demonstration

and quantitative milestones and reasonable further progress (RFP)

elements of the Ada County/Boise PM-10 SIP because the State has not

adopted and submitted to EPA the mandatory wood smoke control

ordinances for Eagle, Garden City, Meridian and unincorporated Ada

County.

DATES: Comments on this proposed action must be received in writing by

October 24, 1994.

ADDRESSES: Written comments should be addressed to: Montel Livingston,

United States Environmental Protection Agency, Air Programs Development

Section, 1200 Sixth Avenue, AT-082, Seattle, Washington, 98101.

FOR FURTHER INFORMATION CONTACT: Stephen Fry, United States

Environmental Protection Agency, Air Programs Development Section, 1200

Sixth Avenue, AT-082, Seattle, Washington, 98101, (206) 553-2575.

SUPPLEMENTARY INFORMATION:

I. Background

The Ada County/Boise, Idaho 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, upon enactment of the Clean Air Act Amendments of

1990\1\ (see 56 FR 56694 (November 6, 1991) and 40 CFR 81.313). The air

quality planning requirements for moderate PM-10 nonattainment areas

are set out in subparts 1 and 4 of title I of the Act.\2\ 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 this proposal and the supporting

rationale. In today's rulemaking action on the State of Idaho's

moderate PM-10 SIP for the Ada County/Boise nonattainment area, EPA is

proposing to apply 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. EPA will consider any timely submitted

comments before taking final action on today's proposal.

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\1\The 1990 Amendments to the Clean Air Act made significant

changes to the Act. See Public Law No. 101-549, 104 Stat. 2399.

References herein are to the Clean Air Act, as amended (CAA or 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) of the

Act) were required to submit, among other things, the following

provisions by November 15, 1991:

1. Provisions to assure that 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 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.

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) of the Act). This permit program element, also

known as the New Source Review (NSR) program, was submitted by the

State of Idaho on May 17, 1994. EPA notified Idaho in a June 10, 1994

letter to the Administrator of the IDEQ that the NSR program submittal

was complete. EPA is currently reviewing Idaho's NSR program submittal

to determine if the program meets the requirements of the CAA. EPA

intends to take action on Idaho's NSR program in a separate document

when EPA has completed its review.

In addition, States containing initial moderate PM-10 nonattainment

areas 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

section 172(c)(9) of the Act and 57 FR 13510-13512 and 13543-13544).

Contingency measures for the Ada County/Boise PM-10 nonattainment area

have not yet been submitted by IDEQ. A findings letter, dated January

13, 1994, was mailed to the Governor of Idaho which informed him that

the State had failed to make the required PM-10 contingency measures

submittal for Ada County/Boise. The State has until July 13, 1995 to

correct this deficiency for Ada County/Boise, or it will face Federal

highway or offset sanctions (see section 179 of the CAA and 58 FR 51270

(October 1, 1993)). EPA intends to take action on the contingency

measures for the Ada County/Boise PM-10 nonattainment area when this

requirement is submitted or intends to impose sanctions in the event

this deficiency is not corrected.

II. This Action

Section 110(k) of the Act sets out provisions governing EPA's

review of SIP submittals (see 57 FR 13565-13566). In this action, as

described below, EPA is proposing to grant full approval of the

emission inventory element and exclusion from the PM-10 precursor

control requirements. These elements of the State's moderate PM-10

nonattainment SIP submittal for Ada County/Boise are separable and

independent of the provisions that the State has not adequately

addressed.

Also as described below, EPA is proposing to grant a limited

approval of the control measures that have been submitted by the State

as of this date. EPA may grant a limited approval of these control

measures under section 110(k)(3) of the Act, in light of EPA's

authority under section 301(a) of the Act to adopt regulations

necessary to further air quality by strengthening the SIP. The proposed

approval of these control measures is limited, however, in that EPA is

not proposing that these control measures satisfy the specific

requirements of sections 172(c)(1) and 189(a)(1)(C) to implement RACM,

including RACT, in moderate PM-10 nonattainment areas. EPA believes,

however, that the control measures adopted and submitted as of this

date will achieve PM-10 emissions reductions in the Ada County/Boise

nonattainment area. Thus, EPA is proposing to approve these control

measures for the limited purpose of strengthening the SIP and making

them federally enforceable (see e.g. sections 113 and 302(q) of the

Act).

Finally, because the State has not yet adopted into the SIP and

submitted to EPA certain control measures on which it relies in the SIP

to demonstrate timely attainment and continued maintenance of the PM-10

NAAQS in the Ada County Boise nonattainment area, EPA is proposing to

disapprove the RACM (including RACT) element. In addition, because the

attainment demonstration and quantitative milestones and reasonable

further progress (RFP) elements of the Ada County/Boise PM-10 SIP

depend in part on the control measures which the State has not yet

adopted and submitted to EPA, EPA is also proposing to disapprove these

elements. If this proposed disapproval becomes final, it will begin the

period for the imposition of discretionary sanctions under section

110(m) of the Act and the 18-month sanctions clock for the imposition

of mandatory sanctions under section 179 of the Act. If finalized, this

disapproval will also authorize EPA to issue a Federal implementation

plan as provided in section 110(c)(1) of the Act.

If, however, prior to EPA's final action on this proposal the State

submits the additional control measures on which it relies and, based

on EPA's review, these additional control measures adequately address

the outstanding deficiencies, EPA will consider withdrawing this

limited approval/disapproval and will instead propose full approval of

the PM-10 plan for Ada County/Boise relative to those moderate area PM-

10 SIP requirements which were due November 15, 1991. EPA invites

public comment on its proposed action.

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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EPA also must determine whether a submittal is complete and

therefore warrants further EPA review and action (see section 110(k)(1)

of the Act 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 IDEQ initially held a public hearing on the Ada County/Boise

PM-10 air quality improvement plan on October 11, 1990, and received no

public comments regarding the plan. However, following one 24-hour PM-

10 exceedance on January 7, 1991 and two near exceedances on January 4

and 6, 1991, EPA requested on March 22, 1991 that IDEQ modify the PM-10

plan to better ensure healthful air in the future. IDEQ revised the PM-

10 plan and the State of Idaho subsequently held a public hearing on

the modified Ada County/Boise PM-10 plan on November 4, 1991. Again,

IDEQ received no public comments. The modified PM-10 plan was then

adopted by the State of Idaho on November 14, 1991, and the plan was

submitted to EPA on November 15, 1991 as a proposed revision to the

SIP.

The SIP revision was reviewed by EPA to determine completeness

shortly after its submittal in accordance with the completeness

criteria set out at 40 CFR part 51, appendix V. A letter dated April

27, 1992 was forwarded to the Administrator of the Idaho Division of

Environmental Quality indicating the completeness of the submittal and

the next steps to be taken in the review process.

2. Accurate Emissions Inventory

Section 172(c)(3) of the Act requires that nonattainment plan

provisions include a comprehensive, accurate, current inventory of

actual emissions from all sources of relevant pollutants in the

nonattainment area. The emissions inventory should also include a

comprehensive, accurate, and current inventory of allowable emissions

in the area (see e.g. section 110(a)(2)(K) of the Act). Because the

submission of such inventories is necessary to an area's attainment

demonstration (or demonstration that the area cannot practicably

attain), the emissions inventories must be received with the

demonstration submission (see 57 FR 13539).

The base year emission inventory (1987) developed for Ada County/

Boise identified the major sources of PM-10 concentrations during 24-

hour worst case winter periods as residential wood combustion (71%),

fugitive road dust (15%), industrial (7%) and other sources, including

but not limited to, transportation, construction and open burning (7%).

Annual emissions for 1987 were fugitive road dust (51%), residential

wood combustion (23%), building construction (12%), transportation

(6%), industrial (6%) and other sources (2%).

EPA is proposing to approve the emissions inventory because it

generally appears to be accurate and comprehensive, and provides a

sufficient basis for determining the adequacy of the attainment

demonstration for this area consistent with the requirements of

sections 172(c)(3) and 110(a)(2)(K) of the Clean Air Act.4 Full

approval of this element is appropriate because it is separable and

independent of the deficiency which prevents full approval of the SIP,

namely, the adoption and submission of all control measures on which

the State relies in the SIP. The emissions inventory is a separable

component of the Ada County/Boise PM-10 SIP because it represents an

assessment of PM-10 emissions in the area prior to the adoption of

control measures and will not change as the result of any additional

control measures adopted. For further details, see 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 amended Act (see section

193 of the Act).

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3. Control Measures

As noted above, 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) of the Act). 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 (see 57 FR 13540-

13544).

Idaho's SIP submittals for Ada County/Boise do not provide for

implementation of control measures which assure timely attainment of

the PM-10 NAAQS, nor, in the alternative, do they show that the

adoption of available control measures would be economically or

technologically unreasonable. Therefore, the submittals do not meet the

specific statutory requirements to provide for the implementation of

RACM (including RACT) in moderate PM-10 nonattainment areas.

a. Residential Wood Burning Program

The State relies on control strategies designed to reduce wood

smoke for timely attainment of the 24-hour and annual PM-10 standards.

The residential wood burning program has three main objectives: 1.

Reduce wood burning during critical periods; 2. Improve the performance

and efficiency of wood heating equipment; and 3. Provide reasonable

alternatives to wood heat. The State's available control measures to be

implemented in the Ada County/Boise nonattainment area that address the

main objectives include the following:

(1) Episodic Wood Burning Curtailment Program

The SIP submittal discusses an episodic two-stage voluntary and

mandatory wood burning curtailments in the Ada County/Boise

nonattainment area. The first stage is a voluntary burn ban when 24-

hour PM-10 levels in the nonattainment area are predicted to equal or

exceed 100 g/m\3\. The 24-hour PM-10 prediction is made after

an IDEQ meteorologist calculates lower atmospheric stability and

evaluates PM-10 equivalent sampler, nephelometer, upper air temperature

sounding, snow cover, surface temperature, delta temperature, wind

speed, cloud cover, National Weather Service and occasionally

commercial weather service data.

The second stage is a mandatory curtailment program. In 1986, Boise

adopted an ordinance imposing a mandatory burn ban when 24-hour PM-10

levels actually attain or exceed 110 g/m\3\, and stable

meteorological conditions are expected to persist for the next 24 hours

(see Boise City Code, Tit. 4, Ch. 6). This ordinance was amended in

January 1993 to reduce the trigger point for mandatory burn bans from

110 g/m\3\ to 100 g/m\3\ (see Boise City Code, Sec.

4-6-4).

The SIP states that Garden City also has a mandatory curtailment

program, but no documentation of the Garden City program was included

in the initial SIP submittal. The SIP further states that the State

would attempt to persuade other Ada County jurisdictions to implement

mandatory curtailment programs similar to the Boise program. To date,

EPA has informally received copies of mandatory wood smoke curtailment

ordinances (some are signed and others are unsigned) for unincorporated

Ada County and the cities of Eagle, Garden City and Meridian. These

ordinances, however, have not been adopted into the SIP and have not

been formally submitted to EPA.

In its SIP submittal, the State notes that a county-wide5

mandatory wood smoke curtailment program is necessary to bring the Ada

County/Boise nonattainment area into timely attainment of the NAAQS

because approximately 30% of the wood burning in the area occurs

outside of areas covered by mandatory wood burning restrictions. For

this reason, the SIP submittal for Ada County/Boise cannot be

considered to satisfy the RACM requirement because the State has not

adopted as part of the SIP and submitted to EPA those available control

measures necessary for expeditious attainment of the PM-10 NAAQS (or

shown that all economically and technologically feasible control

measures have been implemented and timely attainment is impracticable).

Specifically, the State has not adopted and submitted mandatory burn

ban ordinances for Garden City, Eagle, Meridian and unincorporated Ada

County. EPA urges the State to promptly adopt and submit to the EPA the

necessary mandatory residential wood smoke burning ban ordinances on

which the State relies in its SIP submittal.

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\5\In a letter to the EPA, dated August 14, 1992, the State

argued for the exclusion of the locality south of Amity Road and

west of Cloverdale Road (the Kuna area) from proposed mandatory burn

bans because the area is located in a separate stream drainage from

the Boise River Valley, and thus does not significantly contribute

smoke to the valley where the PM-10 exceedances have been recorded.

The State also noted that the emission inventory, modeling and

visibility observations indicate that the Kuna area air quality is

markedly cleaner than the ambient air in the Boise River Valley,

which includes downtown Boise. EPA acknowledged in an August 27,

1992 letter to IDEQ, that the State had adequately demonstrated that

mandatory burn bans in the Kuna area were unnecessary to demonstrate

attainment and EPA formally proposes to make this determination in

today's action.

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Although the SIP submittal cannot be considered to satisfy the RACM

requirement at this time, EPA is proposing limited approval of the

Boise wood smoke control ordinance, Boise City Code Tit. 4, Ch. 6,

pursuant to sections 110(k)(3) and 301(a) of the Act in order to

strengthen the SIP and make the ordinance federally enforceable. EPA

believes that this control measure will result in reductions in PM-10

emissions in the nonattainment area and thus advance the Act's air

quality-related protection goals.

(2) Wood Smoke Public Education/Awareness Program

The wood smoke public education/awareness program for the Ada

County/Boise nonattainment area plays a critical role in achieving the

aforementioned three main objectives of IDEQ's residential wood burning

program. The wood smoke public education/awareness program was first

officially initiated in 1986, following the passage of Boise's local

wood burning ordinance. Brochures, television and radio public service

announcements, newspaper advertisements, outreach meetings at public

schools, media interviews and press conferences are the main components

of the integrated awareness package. Various points have been focused

on during the program's existence, including the nature of the wood

smoke problem, health impacts, meteorological factors (including tips

asking citizens to refrain from burning on clear, calm and/or cool

days) and how to burn cleaner.

IDEQ and the City of Boise are responsible for a majority of the

continuing wood smoke public education/awareness program. According to

IDEQ, local surveys and building department statistics show reductions

in the numbers of wood stoves installed, reduction in the average

volume of wood burned per household and widespread public cooperation

during poor air quality periods as the result of the wood smoke public

education efforts. These surveys and statistics are the basis for the

10% annual credit IDEQ is claiming for the wood smoke public education/

awareness program during 1990 through the year 2000.

EPA believes that IDEQ has adequately demonstrated, through surveys

and building department statistics, that the well-established,

extensive, wood smoke public education/awareness program for the Ada

County/Boise PM-10 nonattainment area has achieved at least a 10

percent wood smoke emission reduction. Therefore, EPA proposes limited

approval of the wood smoke public education/awareness program described

in the Ada County/Boise SIP as a SIP strengthening measure and proposes

to accept the 10 percent credit requested by the IDEQ.

(3) Wood Stove Certification

The City of Boise's 1986 wood burning ordinance initiated a

requirement mandating all wood burning appliances sold and installed

within the city to be certified as meeting certain emission standards

(see Boise City Code, Sec. 4-6-9). The ordinance is enforced by city

and county building department inspectors. The initial certification

program was based on the Oregon Department of Environmental Quality

standards. The current program is based on the national wood burning

device New Source Performance Standards developed by the EPA.

The implementation and enforcement of the certification program

resulted in the City of Boise accelerating the introduction of

certified stoves and the phase-out of old, high emission uncertified

stoves. However, IDEQ does not take any credit for the emission

reductions that have resulted from the wood stove certification

program.6

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\6\According to the SIP submittal, Meridian, Eagle, Garden City,

unincorporated Ada County, Nampa and Emmett also require that only

certified wood stoves be sold and installed within their respective

jurisdictions. However, no documentation (i.e. ordinances)

supporting this statement was included in the SIP submittal.

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Based upon the enforceability of the City of Boise wood stove

certification program and its advancement of the PM-10 air quality

goals, EPA is proposing limited approval of this program as a SIP

strengthening measure.

(4) Wood Stove Change-Out Program

An initial feature of the City of Boise's 1986 wood burning

ordinance was the development of a financial incentive program to

replace uncertified wood stoves with certified stoves (see Boise City

Code, Sec. 4-6-18). Low or no interest loans were offered to

individuals participating in the program. In order to receive a loan,

the participant was required to give the uncertified wood stove to the

city building department for destruction. The loan program began in

September 1986 and ended in September 1988. Approximately $800,000 in

loans were made, resulting in the replacement of 494 uncertified wood

stoves with cleaner heating devices. IDEQ does not take credit for

reductions in the emissions, even though 84 uncertified wood stoves

were removed from the airshed after the area source emission inventory

base year (1987).

The Idaho Department of Water Resources (IDWR) also operated a wood

stove change-out loan program, which ran from May 1987 to May 1993. 186

uncertified wood stoves were changed-out with cleaner heating devices

during that period, with a majority of the replacements occurring

during 1988-1993. Again, IDEQ did not take credit for these PM-10

emission reductions. Both the Boise and IDWR wood stove change-out loan

programs strengthen the SIP and further assure that these wood smoke

sources will not contribute to a future PM-10 exceedance. Accordingly,

EPA proposes limited approval of the wood stove change-out loan program

because it strengthens the SIP and enhances PM-10 air quality

protection for the Ada County/Boise PM-10 nonattainment area.

b. Other Sources

As noted, RACM does not require controls on emissions from sources

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

implementation of all available control measures where an area

demonstrates timely attainment and the implementation of additional

controls would not expedite attainment (see 57 FR 13540-13544).

IDEQ has determined, through its analysis of the nonattainment

area, that road dust contributed 15 percent of the PM-10 concentration

on the worst case day in base year 1987. IDEQ did not propose controls

for road dust. Rather, the State relies on wood smoke controls to

demonstrate timely attainment of the 24-hour PM-10 standard, concluding

that the implementation of additional control measures for road dust

would not expedite attainment. However, the State's control strategy

assumes the timely adoption and submittal of effective and enforceable

mandatory wood smoke curtailment ordinances for the remainder of the

nonattainment area. While such mandatory wood smoke curtailment

ordinances, in conjunction with the other wood smoke controls described

above, may demonstrate attainment of the standard, all of these control

measures have not in fact been submitted. Thus, RACM is not met because

it has not been demonstrated that the implementation of available

control measures could not expedite attainment or that the

implementation of such measures is technologically or economically

unreasonable.

It is EPA's view that RACM does not require the implementation of

controls for prescribed silvicultural and agricultural burning for the

Ada County/Boise nonattainment area because the area is not

significantly impacted by those activities. Similarly, EPA believes

that RACT does not require the implementation of control technology for

stationary sources of PM-10 in the nonattainment area, because the area

is primarily characterized by commercial, residential and light

industrial uses. There are currently no major stationary sources

operating in the Ada County/Boise PM-10 nonattainment area and large

stationary sources do not contribute significantly to the PM-10 air

quality problem in Boise.

In summary, EPA is proposing to approve, under the authority of

sections 110(k)(3) and 301(a) of the Act and for the limited purpose of

strengthening the SIP and making such control measures federally

enforceable, the control measures that have been submitted to date as

part of the PM-10 SIP for the Ada County/Boise nonattainment area.

These measures include the voluntary episodic wood burning curtailment

program for the entire nonattainment area, the mandatory episodic wood

burning curtailment program for the City of Boise, the wood smoke

public education/awareness program, the wood stove certification

program and the wood stove change-out program. A final limited approval

of these existing control measures would not mean that EPA has approved

these control measures as satisfying the specific Act requirement for

the State to implement RACM (including RACT) in moderate PM-10

nonattainment areas (see sections 172(c)(1) and 189(a)(1)(C)). Rather,

limited approval of these measures by EPA means only that these control

requirements become part of the applicable implementation plan and are

federally enforceable by EPA (see, e.g., sections 302(q) and 113 of the

Act). EPA is concurrently proposing to disapprove the RACM (including

RACT) element because the State has not adopted and submitted to EPA

all of the mandatory wood smoke control ordinances on which it relies

in its SIP submittal. A final disapproval of the Ada County/Boise PM-10

SIP RACM (including RACT) element would start the 18 month clock for

the imposition of mandatory sanctions under section 179 of the Act and

the two-year clock for the promulgation of a Federal Implementation

Plan under section 110(c)(1) of the Act.

4. Demonstration

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, the State must

show attainment by December 31, 1994 is impracticable. 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.).

As indicated in the General Preamble, 57 FR 13539, EPA has

developed a supplemental attainment demonstration policy for initial

PM-10 nonattainment areas. This policy provides additional flexibility

in meeting the PM-10 attainment demonstration requirements. An earlier

April 2, 1991 memorandum titled, ``PM-10 Moderate Area SIP Guidance:

Final Staff Work Product'' contained ``Attachment 5'' describing the

same policy.

IDEQ conducted an attainment demonstration based upon WYNDvalley, a

non-guideline dispersion model that EPA recommended be used in the Ada

County/Boise nonattainment area. WYNDvalley is applicable in light and

variable wind scenarios in regions influenced by complex terrain. Cold

temperatures and light winds with limited vertical mixing create

stagnant weather conditions in the Boise River Valley. All of the PM-10

exceedances observed in the Ada County/Boise nonattainment area have

occurred during stagnant wintertime conditions.

The attainment demonstration indicates that the Ada County/Boise

nonattainment area will be in attainment of the 24-hour PM-10 NAAQS

during the entire period of 1993 to 2000, with the maximum predicted

24-hour concentration of 147 g/m3 occurring in 1995. The

demonstration also addresses the quantitative milestone requirement

(discussed below) by showing that the PM-10 NAAQS will be maintained

after December 31, 1994 by predicting a 24-hour worst case day design

concentration of 144 g/m3 for the year 2000. According to

EPA's review, which corrected for the use of non-reference PM-10 data

in 1986 and 1987 (i.e. Hi-Vol SA321A gravimetric PM-10 sampler), the

Ada County/Boise area has never violated the annual arithmetic mean PM-

10 standard. The highest valid three-year annual average in the

nonattainment area is 43 g/m3 during 1987-1989, while the

lowest three-year average is 39 g/m3 during 1990-1992.

The control strategy used to achieve these design concentrations

and demonstrate attainment of both the 24-hour and annual PM-10

standards, however, relies on mandatory wood smoke control programs in

Eagle, Garden City, Meridian and unincorporated Ada County. As

discussed above in the section titled ``Control Measures,'' the State

has not adopted these ordinances as part of the SIP and submitted them

to EPA. Accordingly, EPA proposes to disapprove the attainment

demonstration. More detailed description of the attainment

demonstration is contained in the TSD accompanying this document.

5. 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 years until the area is redesignated attainment

and which demonstrate RFP, as defined in section 171(1) of the Act,

toward attainment by December 31, 1994 (see section 189(c) of the CAA).

Although 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

three-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 three-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 that two milestones will be

achieved (1st milestone: November 15, 1991 through November 15, 1994;

2nd milestone: November 15, 1994 through November 15, 1997). For areas

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

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

the standards.\7\

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\7\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 for an area as attainment is contingent upon several

factors and future events. Therefore, EPA believes it is reasonable

for States to initially address at least the first two milestones.

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.

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For the initial PM-10 nonattainment areas that demonstrate

attainment, the emissions reduction progress made between the SIP

submittal (due date of November 15, 1991) and the attainment date of

December 31, 1994 (46 days beyond the November 15, 1994 milestone date)

will satisfy the first quantitative milestone. The de minimis timing

differential makes it administratively impracticable to require

separate milestone and attainment demonstrations (see 57 FR 13539). In

implementing the quantitative milestone and RFP provisions for this

initial moderate area, EPA has reviewed the attainment demonstration

for the area to determine the nature of any milestones necessary to

ensure timely attainment and whether annual incremental reductions

should be required in order to ensure attainment of the PM-10 NAAQS by

December 31, 1994.

The SIP purports to demonstrate attainment by 1994 and maintenance

through 2000, which would satisfy three milestones. However, as

discussed above, the maintenance demonstration and, therefore, the

quantitative milestones directly depend on mandatory wood smoke control

programs in Eagle, Garden City, Meridian and unincorporated Ada County.

As discussed above in the section titled ``Control Measures,'' the

State has not adopted these ordinances as part of the SIP and submitted

them to EPA. Accordingly, EPA proposes to disapprove the quantitative

milestone requirement (see General Preamble, 57 FR 13565 and July 9,

1992 EPA memorandum regarding ``Processing of State Implementation Plan

(SIP) Submittals'').

6. 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).

Because the emission inventory for the Ada County/Boise PM-10

nonattainment area did not reveal any major stationary sources,

including any major stationary sources of PM-10 precursors, EPA is

proposing to grant the exclusion from control requirements authorized

under section 189(e) for major stationary sources of PM-10 precursors.

7. Enforceability Issues

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

IDEQ and EPA (see sections 172(c)(6) and 110(a)(2)(A) of the Act and 57

FR 13556). EPA criteria addressing the enforceability of SIP's and SIP

revisions were set forth 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)).

The specific control measures that were submitted as part of the

SIP are addressed above under the section headed ``Control Measures.''

As also discussed in that section, although the State relies on

mandatory wood smoke control ordinances throughout the entire

nonattainment area (except for the Kuna area) to demonstrate attainment

and maintenance of the standard, the State has adopted and submitted to

EPA a mandatory wood smoke curtailment ordinance only for the City of

Boise. The necessary ordinances for Eagle, Garden City, Meridian and

unincorporated Ada County, as well as evidence that the wood smoke

control programs for these areas are adequately funded, implemented,

enforced and maintained, have not been submitted at this time.

EPA has reviewed for enforceability the wood smoke ordinance for

the City of Boise, which includes the mandatory curtailment program and

the wood stove certification program for Boise, and has determined that

it meets all of the criteria included in the September 23, 1987, Potter

Memorandum. Exemptions from the mandatory burn bans are allowed only

for the following reasons and must be approved by the City Building

Department: a. wood burning is the resident's sole source of heat; b.

curtailment would cause unreasonable economic hardship for low income

households; or c. the wood burning device being utilized is certified

by the Oregon Department of Environmental Quality or EPA as ``clean

burning''. This is consistent with the recommendations for woodburning

curtailment programs provided in EPA's Guidance Document for

Residential Wood Combustion Emission Control Measures. The wood stove

certification program does not contain any exemptions. Compliance with

wood burning curtailments and the certification program is mainly

achieved by responding to citizen complaints, but the City of Boise has

limited personnel that independently monitor for noncompliance.

Enforcement of burn bans and the certification program follows three

progressive steps: 1. written warning; 2. fine; and 3. further legal

action against the violator, if needed. IDEQ's submittals and the TSD

contain further information on the enforceability of the Boise wood

smoke curtailment ordinance and the personnel and funding intended to

support effective implementation of this ordinance. In these respects,

this control measure appears to be enforceable.

Section 110(a)(2)(E) of the Act requires that, where the State has

relied on a local or regional government, agency or instrumentality for

the implementation of any plan provision, the plan must provide

necessary assurances that the State has responsibility for ensuring

adequate implementation of such plan provision. The State's initial SIP

submittal did not address the requirement of section 110(a)(2)(E).

However, in a recent submission from the State addressing State

responsibility for local control measures, such as the Boise wood smoke

control ordinance, the State indicated that it relies on its existing

ability to issue an operating permit to any stationary source when the

Department determines that emission reductions from that source are

necessary to attain or maintain a NAAQS (see Idaho Administrative

Procedures Act (IDAPA) 16.01.01012.03.c (June 1993); IDAPA

16.01.01401.03 (May 1994)). The submission includes a copy of an

opinion from the Attorney General's office stating that such permits

could be issued to the owners of wood stoves and could include

provisions directly implementing local mandatory wood smoke curtailment

ordinances in the event a local entity fails to implement or enforce

its respective local ordinance. This mechanism appears to satisfy the

requirements of section 110(a)(2)(E) of the Act for State

responsibility for local wood smoke control ordinances.

EPA is reserving judgment on the enforceability of the outstanding

control measures (i.e. mandatory wood smoke curtailment programs for

Eagle, Garden City, Meridian and unincorporated Ada County) and the

adequacy of the related enforcement programs until EPA receives and

reviews these measures.

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 and 13543-13544).

These measures must have been 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 reasonable further progress or attain the PM-10

NAAQS by the applicable statutory deadline.

Contingency measures for the Ada County/Boise PM-10 nonattainment

area have not yet been submitted by IDEQ. A findings letter, dated

January 13, 1994, was mailed to the Governor of Idaho informing him

that the State had failed to make the required PM-10 contingency

measures submittal for the Ada County/Boise SIP. The State has until

July 13, 1995 to correct this deficiency for Ada County/Boise, or it

will face Federal highway and/or offset sanctions (see section 179 of

the CAA).

EPA intends to take action on the contingency measures for the Ada

County/Boise PM-10 nonattainment area when this requirement is

submitted or intends to impose sanctions in the event this deficiency

is not corrected.

9. Transportation Conformity Protective Finding

Section 176(c)(4) of the CAA and the regulations implementing that

provision require that transportation plans, programs, and projects

which are funded or approved under title 23 U.S.C. or the Federal

Transit Act must conform with State or Federal air quality

implementation plans (see 58 FR 62188 (November 24, 1993)). According

to 58 FR 62228, Sec. 51.448, areas which submitted a control strategy

implementation plan before November 24, 1993 must be demonstrated to

conform according to transitional period criteria and procedures by

November 25, 1994. Otherwise, their conformity status will lapse, and

no new project-level conformity determinations may be made. Under 40

CFR 51.448(a)(2),\8\ if EPA disapproves a control strategy

implementation plan revision submitted by the State and notifies the

State, the Metropolitan Planning Organization (MPO), and the Department

of Transportation (DOT), the conformity status of the transportation

plan and transportation improvement program (TIP) lapses 120 days after

EPA's disapproval. After that time, no new project-level conformity

determinations may be made and no new transportation plan, TIP, or

project may be found to conform until another control strategy

implementation plan revision is submitted and conformity is

demonstrated according to transitional period criteria and procedures.

Note that these conformity consequences of a disapproval of a control

strategy are in addition to the discretionary sanctions, which may be

imposed under section 110(m) of the Act at any time following a

disapproval, and the mandatory sanctions, which must be imposed under

section 179 of the Act beginning 18 months following a disapproval.

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\8\Although Secs. 51.448(d) (2) and (3) by their terms apply to

``areas which submitted a control strategy implementation plan

before November 24, 1993,'' the effective date of the conformity

rule, EPA intended that these provisions apply only to plans on

which final action had been taken prior to the effective date of the

rule. EPA intended the provisions of Sec. 51.448(a) (2) and (3) to

apply to all plans, regardless of the date of submission, on which

final action was not taken until after November 24, 1993. In other

words, EPA intended that the conformity status of the transportation

plan and TIP lapse 120 days or, in the case of a protective finding,

one year after the later of the effective date of the conformity

rule (November 24, 1994) or the disapproval of the control strategy.

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Section 51.448(a)(3), however, allows EPA to extend the 120-day

lapse period to one year from the date of disapproval if EPA determines

that the control strategy contained in the revision would have been

considered approvable with respect to requirements for emission

reductions if all committed measures had been submitted in enforceable

form as required by section 110(a)(2)(A) of the Act. If EPA makes such

a ``protective finding,'' the transportation conformity plan and TIP

will be valid for 12 months following the date of disapproval and the

conformity status of the transportation plan and TIP will lapse 12

months following the date of disapproval unless within that time

another control strategy implementation plan revision is submitted to

EPA and found to be complete.

If, as proposed in this action, EPA disapproves the control

strategy in the moderate area SIP for the Ada County/Boise

nonattainment area, under Sec. 51.448(a)(2) the conformity status of

the transportation plan and TIP would lapse 120 days after the

effective date of the disapproval. EPA has evidence, however, that the

wood smoke control ordinances for the cities of Eagle, Garden City and

Meridian, and unincorporated Ada County are enforceable as a matter of

local law, and believes that these control measures would have been

considered approvable with respect to requirements for emission

reductions if each of these control measures had been submitted to EPA

in enforceable form as required by section 110(a)(2)(A). Therefore, EPA

proposes that the 120-day lapse period be extended to one year under 40

CFR 51.448(a)(3). Accordingly, if EPA takes final action on this

proposal, and the RACM (including RACT) requirement, attainment

demonstration and quantitative milestones and RFP elements of the Ada

County/Boise moderate PM-10 nonattainment SIP are disapproved, then the

State of Idaho's transportation plan and TIP may be found to conform

for 12 months past the effective date of the PM-10 SIP disapproval. The

conformity status of the transportation plan and TIP would then lapse

12 months following the effective date of final action on this proposal

unless within that time another control strategy implementation plan

revision is submitted to EPA and found to be complete.

III. Implications of This Action

EPA is proposing to approve the emission inventory and, as

described in the TSD, several submittals to address requirements of

section 110(a)(2) of the Act, including the: a. Monitoring network (CAA

section 110(a)(2)(B)); b. consultation and public notification/process

(CAA section 110(a)(2)(J); c. provisions for revising the plan (CAA

section 110(a)(2)(H)); and d. prohibiting sources from significantly

impacting other states (CAA section 110(a)(2)(D)). EPA is also

proposing to grant the exclusion from precursor control requirements

authorized under section 189(e) of the Act. EPA is proposing limited

approval of the control measures that have been submitted by the State

as of this date under the authority of sections 110(k)(3) and 301(a) of

the Act for the limited purpose of strengthening the SIP and making

them federally enforceable. EPA believes making these control measures

federally enforceable will achieve PM-10 emissions reductions in the

Ada County/Boise nonattainment area and, therefore, advances the NAAQS-

related goals of the CAA. EPA is proposing disapproval of these control

measures as meeting the RACM (including RACT) requirement, because the

State has not adopted as part of the SIP and submitted to EPA those

available control measures necessary for expeditious attainment of the

PM-10 NAAQS (or shown that all economically and technologically

feasible control measures have been implemented and timely attainment

is impracticable), specifically, mandatory burn ban ordinances for

Garden City, Eagle, Meridian and unincorporated Ada County. In

addition, because the attainment demonstration and quantitative

milestones and reasonable further progress (RFP) elements of the Ada

County/Boise PM-10 SIP depend in part on the control measures which the

State has not yet adopted and submitted to EPA, EPA is also proposing

to disapprove these elements.

A final disapproval of these Ada County/Boise PM-10 SIP elements

will authorize the imposition of discretionary sanctions under section

110(m) of the Act, and will institute the 18-month clock for the

imposition of mandatory sanctions under section 179 of the Act and the

two-year clock for the promulgation of a Federal Implementation Plan

under section 110(c)(1) of the Act.

If, however, the State submits the additional control measures on

which it relies in its SIP submittal and, based on EPA's review, these

additional control measures adequately address the outstanding

deficiencies, EPA will consider withdrawing this limited approval/

disapproval and instead proposing full approval of the PM-10 plan for

Ada County/Boise relative to those moderate area PM-10 SIP requirements

which were due November 15, 1991.

IV. Request for Public Comments

EPA is requesting comments on all aspects of this proposal. As

indicated at the outset of this document, EPA will consider any

comments postmarked by October 24, 1994.

V. 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. The OMB has exempted this regulatory action from

E.O. 12866 review.

Nothing in this action should be construed as permitting or

allowing or establishing a precedent for any future request for

revision to any SIP. Each request for revision to the SIP shall be

considered separately in light of specific technical, economic and

environmental factors and in relation to relevant statutory and

regulatory requirements.

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 sections 110 and 301 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

(see 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)). EPA's disapproval of the State request

under section 110 and subchapter I, part D of the CAA does not affect

any existing requirements applicable to small entities. Any pre-

existing Federal requirements remain in place after this disapproval.

Federal disapproval of the State submittal does not affect its state-

enforceability. Moreover, EPA's disapproval of the submittal does not

impose any new Federal requirements. Therefore, EPA certifies that this

disapproval action does not have a significant impact on a substantial

number of small entities because it does not impose any new Federal

requirements.

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

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Incorporation by

reference, Intergovernmental relations, Particulate matter, Reporting

and recordkeeping requirements.

Dated: September 13, 1994.

Jane S. Moore,

Acting Regional Administrator.

[FR Doc. 94-23496 Filed 9-21-94; 8:45 am]

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