Clean Air Act Approval and Promulgation of State Implementation Plan for Montana; Butte; PMINF10 Contingency Measures and Revisions to the Attainment and Maintenance Demonstrations

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[MT26-1-6692a; FRL-5163-8]

Clean Air Act Approval and Promulgation of State Implementation

Plan for Montana; Butte; PM10 Contingency Measures and Revisions

to the Attainment and Maintenance Demonstrations

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

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SUMMARY: EPA approves the State implementation plan (SIP) revisions

submitted by the State of Montana with a letter dated August 26, 1994.

This submittal addresses, for the Butte moderate PM10

nonattainment area, the Federal Clean Air Act requirement to submit

contingency measures for particulate matter with an aerodynamic

diameter less than or equal to a nominal [[Page 15057]] 10 micrometers

(PM10) for areas designated as nonattainment for the PM10

National Ambient Air Quality Standards (NAAQS). This submittal also

includes revisions to the attainment and maintenance demonstrations for

the moderate PM10 nonattainment area SIP for Butte due to the

inclusion of new emission limits in a revised air quality permit for

Montana Resources, Inc. Since the SIP adequately addresses the

requirement for contingency measures and, with the new emission limits

for Montana Resources, Inc., still adequately demonstrates attainment

and maintenance of the PM10 NAAQS in Butte, EPA approves these

revisions.

DATES: This final rule will become effective on May 22, 1995 unless

notice is received by April 21, 1995 that someone wishes to submit

adverse or critical comments. If the effective date is delayed, timely

notice will be published in the Federal Register.

ADDRESSES: Copies of the State's submittal and other information are

available for inspection during normal business hours at the following

locations:

Air Programs Branch, Environmental Protection Agency, Region VIII, 999

18th Street, suite 500, Denver, Colorado 80202-2405

Montana Department of Health and Environmental Sciences, Air Quality

Division, Cogswell Building, Helena, Montana 59620-0901

The Air and Radiation Docket and Information Center, 401 M Street SW.,

Washington, DC 20460.

FOR FURTHER INFORMATION CONTACT: Amy Platt, 8ART-AP, Environmental

Protection Agency, Region VIII, 999 18th Street, suite 500, Denver,

Colorado, (303) 293-1769.

SUPPLEMENTARY INFORMATION:

I. Background

The Butte, Montana area was designated nonattainment for PM10

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 (Nov. 6, 1991); 40 CFR 81.327 (Silver Bow

County--Butte). The air quality planning requirements for moderate

PM10 nonattainment areas are set out in subparts 1 and 4 of part

D, title I of the Act.2 The EPA has issued a ``General Preamble''

describing EPA's preliminary views on how EPA intends to review SIPs

and SIP revisions submitted under Title I of the Act, including those

State submittals containing moderate PM10 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 action and the supporting rationale.

\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. Section 7401, et seq.

\2\Subpart 1 contains provisions applicable to nonattainment

areas generally and Subpart 4 contains provisions specifically

applicable to PM10 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 PM10 nonattainment

areas such as Butte were required to submit, among other things,

several provisions by November 15, 1991. These provisions, including an

attainment demonstration (or demonstration that timely attainment is

impracticable), are described in EPA's final rulemaking on the Butte

moderate PM10 nonattainment area SIP (59 FR 11550-11554, March 11,

1994). Such States were also required to submit contingency measures by

November 15, 1993 (see 57 FR 13543). These measures must become

effective, without further action by the State or EPA, upon a

determination by EPA that the area has failed to achieve reasonable

further progress (RFP) or to attain the PM10 National Ambient Air

Quality Standards (NAAQS) by the applicable statutory deadline. See

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

II. This Action

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

review of SIP submittals (see 57 FR 13565-13566). The Governor of

Montana submitted revisions to the SIP for Butte with a letter dated

August 26, 1994. The revisions address PM10 emissions in Butte,

including modified emission limitations for Montana Resources, Inc. and

the associated attainment and maintenance demonstrations, as well as

contingency measures.

A. Analysis of State Submission

1. Procedural Background

The Act requires States to observe certain procedural requirements

in developing implementation plans and plan revisions for submission to

EPA. Section 110(a)(2) of the Act provides that each implementation

plan submitted by a State must be adopted after reasonable notice and

public hearing.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.

\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)

and 57 FR 13565]. The EPA's completeness criteria for SIP submittals

are set out at 40 CFR part 51, appendix V. The EPA attempts to make

completeness determinations within 60 days of receiving a submission.

However, a submittal is deemed complete by operation of law if a

completeness determination is not made by EPA six months after receipt

of the submission.

To entertain public comment, the State of Montana, after providing

adequate notice, held a public hearing on May 20, 1994 to address the

Butte PM10 contingency measures and revisions to the attainment

and maintenance demonstrations for this SIP. Following the Montana

Board of Health and Environmental Sciences public hearing, the Board

adopted the Butte PM10 SIP revisions and contingency measures.

The SIP revisions were reviewed by EPA to determine completeness in

accordance with the completeness criteria set out at 40 CFR part 51,

appendix V. The submittals were found to be complete and a letter dated

November 1, 1994 was forwarded to the Governor indicating the

completeness of the submittal and the next steps to be taken in the

review process.

2. Control Strategy

On March 11, 1994 (59 FR 11550), EPA approved the control measures

in the Butte moderate PM10 nonattainment area SIP as satisfying

the requirement to provide for the implementation of reasonably

available control measures (including reasonable available control

technology). See CAA sections 172(c)(1) and 189(a)(1)(C). The measures

targeted re-entrained road dust, residential wood burning, prescribed

burning, industry, and motor vehicle exhaust. Please see that notice of

final rulemaking and associated Technical Support Document (TSD) for

further details on the specific control measures in the approved SIP.

The subsequent August 26, 1994 submittal included a modification to

the [[Page 15058]] Air Quality Permit for Montana Resources, Inc. (one

of the industries targeted for emissions reductions in the previous SIP

submittal). Permit modification #1749-05, effective January 5, 1994,

allows for production increases in diesel consumption, vehicle miles

travelled by haul trucks, and ore hauled to the primary crusher dump.

These increases were compensated for by the installation of Detroit

Diesel Electronic Controls (DDEC) packages on 11 of 15 haul trucks at

the mine. These controls decrease diesel exhaust emissions from the

haul trucks. In the following table, the PM10 emissions reductions

from base year due to the new permitted limitations are outlined.

------------------------------------------------------------------------

PM10 emissions

Source Control measure reduction from base Effective

year date

------------------------------------------------------------------------

Industry....... Air Quality Permit .................... 1/5/94

Modification #1749-

05 for-.

Montana Resources,

Inc.:

(a) limit winter 88% or 2672.6 tons

PM10 emissions from fewer winter

haul trucks and allowable PM10

support vehicles. emissions.

(b) limit winter 85% or 25.6 tons

PM10 diesel exhaust fewer winter

emissions. allowable PM10

emissions.

(c) limit winter 75% or 55.3 tons

PM10 emissions at fewer winter

ore dump, allowable PM10

molybdenum dryer emissions.

and lime handling.

Combined controls... 2753.5 tons fewer

winter allowable

PM10 emissions.

------------------------------------------------------------------------

The previous version of the permit (i.e., #1749-04) had the

following winter allowable PM10 emissions limits: (1) haul trucks

and support vehicles--250.0 tons; (2) diesel exhaust--6.4 tons; and (3)

ore dump, molybdenum dryer and lime handling--14.2 tons. The current

permit (i.e., #1749-05) modified these numbers to 373.0 tons, 4.6 tons,

and 18.5 tons, respectively. Winter allowable PM10 emissions from

categories (1) and (3) have been increased from the previous version of

the permit. The diesel exhaust (category (2)) winter allowable

PM10 emissions have been decreased. While there is an overall net

increase in emissions from the three categories, the chemical mass

balance (CMB) analyses for the area apportioned a larger percentage

contribution to diesel exhaust. Therefore, there is a net air quality

benefit associated with this permit modification due to the reduction

in diesel exhaust emissions. Further, in all three categories, the

permit modification still represents a significant decrease from base

year winter allowable PM10 emissions (as indicated in the table on

the previous page).

A more detailed discussion of the control measures implemented at

Montana Resources, Inc. can be found in the TSD (available at the EPA

address listed at the beginning of this document). EPA has reviewed the

State's documentation and concluded that it adequately justifies the

modifications to the Montana Resources permit. The implementation of

these measures, along with the control measures that were approved in

the moderate PM10 nonattainment area SIP for Butte on March

11,1994 (59 FR 11550), will result in the attainment of the PM10

NAAQS by December 31, 1994. EPA approves this permit modification as

part of the control strategy for the Butte PM10 SIP as it will not

interfere with timely attainment of the PM10 NAAQS.

3. Revisions to Attainment and Maintenance Demonstrations

The initial moderate PM10 nonattainment areas were required to

submit either a demonstration (including air quality modelling) showing

that the plan will provide for attainment as expeditiously as

practicable or a demonstration that timely attainment is not

practicable (see section 189(a)(1)(B) of the Act). The 24-hour

PM10 NAAQS is 150 micrograms/cubic meter (g/m\3\), and

the standard is attained when the expected number of days per calendar

year with a 24-hour average concentration above 150 g/m\3\ is

equal to or less than one (see 40 CFR 50.6). The annual PM10 NAAQS

is 50 g/m\3\, and the standard is attained when the expected

annual arithmetic mean concentration is less than or equal to 50

g/m\3\ (id.).

CMB receptor modelling in combination with emissions rollback

modelling analysis was chosen as the best tool for the attainment and

maintenance demonstrations of the 24-hour standard. EPA approved

Montana's attainment and maintenance demonstrations for the Butte

moderate PM10 nonattainment area on March 11, 1994 (59 FR 11550-

11554). The 24-hour attainment value (i.e., the ambient PM10 air

quality levels achieved by 1995)\4\ was 144.4 g/m\3\, and the

annual attainment value was 42.1 g/m\3\. The 24-hour

maintenance value (i.e., ambient PM10 air quality levels

maintained through January 1, 1998) was 145.5 g/m\3\, and the

annual maintenance value was 41.7 g/m\3\.

\4\The Clean Air Act calls for attainment by December 31, 1994.

Section 188(c)(1). EPA interprets the State's demonstration as

providing for attainment of the PM10 NAAQS by January 1, 1995.

EPA approved the State's demonstration on the basis of the de

minimis differential between the two dates.

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Due to changes made in Montana Resources, Inc.'s Air Quality Permit

#1749, with a final modification date of January 5, 1994 (#1749-05),

the attainment and maintenance demonstrations for the Butte moderate

PM10 nonattainment area SIP were revised in the August 26, 1994

submittal. The new permitted allowable emission limits were used in the

revised attainment and maintenance demonstrations.

The modifications to the allowable emissions did not result in an

inability to demonstrate timely attainment and maintenance of the

PM10 NAAQS in Butte, but, in fact, showed an improvement. With the

adjustments, the 24-hour attainment value is 142.3 g/m\3\ (2.1

g/m\3\ lower than without the adjustments) and the annual

attainment value is 41.8 g/m\3\ (0.3 g/m\3\ lower

than without the adjustments). With the adjustments, the 24-hour

maintenance value is 142.2 g/m\3\ (3.3 g/m\3\ lower

than without the adjustments) and the annual maintenance value is 40.0

g/m\3\ (1.7 g/m\3\ lower than without the

adjustments).

There is no need to adopt additional control measures based on

these adjusted calculations. The SIP still adequately demonstrates

timely attainment and maintenance of the PM10 NAAQS in Butte and

satisfies the requirement to provide for the implementation of RACM

(including RACT). For a more detailed description of the attainment and

maintenance demonstration revisions, please see the TSD for this

document. [[Page 15059]]

4. Contingency Measures

The Clean Air Act requires States containing PM10

nonattainment areas to adopt contingency measures that will take effect

without further action by the State or EPA upon a determination by EPA

that an area failed to make reasonable further progress or to timely

attain the applicable NAAQS, as described in section 172(c)(9). See

generally 57 FR 13510-13512 and 13543-13544. Pursuant to section

172(b), the Administrator has established a schedule providing that

states containing initial moderate PM10 nonattainment areas shall

submit SIP revisions containing contingency measures no later than

November 15, 1993. (See 57 FR 13543, n. 3.)

The General Preamble further explains that contingency measures for

PM10 should consist of other available control measures, beyond

those necessary to meet the core moderate area control requirement to

implement reasonably available control measures (see Clean Air Act,

sections 172(c)(1) and 189(a)(1)(C)). Based on the statutory structure,

EPA believes that contingency measures must, at a minimum, provide for

continued progress toward the attainment goal during the interim period

between the determination that the SIP has failed to achieve RFP or

provide for timely attainment of the NAAQS and the additional formal

air quality planning following the determination (57 FR 13511).

Section 172(c)(9) of the Act specifies that contingency measures

shall ``take effect * * * without further action by the State or the

[EPA] Administrator.'' EPA has interpreted this requirement (in the

General Preamble at 57 FR 13512) to mean that no further rulemaking

activities by the State or EPA would be needed to implement the

contingency measures. In general, EPA expects all actions needed to

affect full implementation of the measures to occur within 60 days

after EPA notifies the State of its failure to attain the standard or

make RFP.

EPA recognizes that certain actions, such as notification of

sources, modification of permits, etc., may be needed before some

measures could be implemented. However, States must show that their

contingency measures can be implemented with minimal further

administrative action on their part and with no additional rulemaking

action such as public hearing or legislative review.

The PM10 contingency measures for Butte were developed by the

Butte/Silver Bow Health Department (BSBHD) and the Montana Department

of Health and Environmental Sciences (MDHES). At its May 20, 1994

public hearing, the Montana Board of Health and Environmental Sciences

(MBHES) adopted the contingency measures.

The Governor submitted the contingency measures to EPA with a

letter dated August 26, 1994. After reviewing the submittal for

conformance with the completeness criteria in 40 CFR Part 51, Appendix

V, EPA determined the submittal to be complete and notified the

Governor of such determination in a letter dated November 1, 1994.

a. Re-entrained Road Dust Contingency Measure. The Butte/Silver Bow

Health Department adopted a contingency plan that implements the

mandatory use of liquid de-icer on all roads with the exception of

priority routes with extraordinary circumstances existing within the

Butte/Silver Bow Air Pollution Control District. Butte/Silver Bow

Ordinance No. 468 stipulates that within 60 days of notification by EPA

that the SIP for the Butte moderate PM10 nonattainment area has

failed to timely attain the PM10 NAAQS or make reasonable further

progress the following will occur:

Within the Butte/Silver Bow Air Pollution Control District, only

liquid de-icer shall be placed on any road with the exception of

priority routes with extraordinary circumstances existing. During

extraordinary events, priority routes must use sanding material which

has a durability, as defined by the Montana Modified L.A. Abrasion

test, of less than or equal to 7, and has a content of material greater

than 200 mesh, as determined by standard wet sieving methods, which is

less than 3.0% oven dry weight.

b. Contingency Measure for Montana Resources, Inc. Since it was

determined through source apportionment studies that the Montana

Resources facility is one of the largest contributing sources of

uncontrolled ambient PM 10 emissions in the Butte/Silver Bow

PM10 moderate nonattainment area, the State believed that a

contingency measure for Montana Resources was necessary to ensure a

sufficient amount of emissions reduction. In addition to allowing the

production increases as offsets for the installation of DDEC on haul

trucks (as discussed above), a contingency measure was added to Permit

#1749-05. Montana Resources agreed to reduce emission and production

limitations within 60 days of notification by MDHES that the PM10

NAAQS has been exceeded within the Butte/Silver Bow moderate PM10

nonattainment. The contingency measure to be implemented would be to

decrease emission and production levels, as described in section

II.A.5.b. below.

As a result of these permit negotiations, Permit #1749 was modified

to outline the production and emission decreases required for the

contingency measure. The final emission limitations for the

implementation of the contingency measure are outlined in Permit #1749-

05.

5. Effectiveness of the Contingency Measures

a. Re-entrained Road Dust Contingency Measure. If the re-entrained

road dust contingency measure is implemented, the control efficiency of

the re-entrained road dust measures will be 66% in the 24-hour

attainment demonstration (an increase of 14% over the control

efficiency of the re-entrained road dust measures in the original SIP

attainment demonstration). This calculation takes into account the use

of the liquid de-icer, the current requirements for use of washed sand,

and the existing street sweeping measures (see the TSD for the Butte

PM10 SIP for further details on the existing re-entrained road

dust strategies). Total reduction from the contingency measure is

calculated to be 1.5 more tons of PM10 per day than without the

contingency measure.

b. Montana Resources Contingency Measure. If the Montana Resources

contingency measure is implemented, the permit modification requires

the following reductions in winter allowable PM10 emissions. Haul

trucks and support vehicles will be reduced to 250 tons (123 tons less

than without the contingency measure), diesel exhaust will be reduced

to 4.0 tons (0.6 tons less than without the contingency measure), and

the ore dump, lime handling and molybdenum dryer will be reduced to

14.2 tons (4.3 tons less than without the contingency measure). The

combined control of this contingency measure results in 127.9 tons

fewer winter allowable PM10 emissions. See the TSD for further

details on the existing permit limitations and contingency measure

limitations.

EPA believes that these contingency measures are approvable. The

control measures implemented in the PM10 SIP achieve more

emissions reductions than needed to demonstrate attainment of the

PM10 NAAQS, as indicated by the State's predicted 24-hour

attainment concentration of 142.3 g/m\3\ (see Section II.A.2.

above and the TSD). Since the 24-hour PM10 NAAQS is 150

g/m\3\, this established safety margin further supports the

reasonableness of these contingency measures. [[Page 15060]]

6. Enforceability Issues

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

the State and EPA (see sections 172(c)(6), 110(a)(2)(A) and 57 FR

13556). The EPA criteria addressing the enforceability of SIPs 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). State implementation plan

provisions also must contain a program to provide for enforcement of

control measures and other elements in the SIP (see section

110(a)(2)(C)).

The specific measures contained in the Butte contingency plan are

addressed above in sections II.A.4. and II.A.5. The Butte/Silver Bow

air pollution control ordinance, as included in the SIP, is legally

enforceable by BSHD. There are penalties for noncompliance with

Ordinance No. 468 (regarding liquid de-icer application).

If a State relies on a local government for the implementation of

any plan provision, then, according to Section 110(a)(2)(E)(iii) of the

Act, the State must provide necessary assurances that the State has

responsibility for ensuring adequate implementation of such plan

provision. A State would have responsibility to ensure adequate

implementation if, for example, the State has the authority and

resources to implement the provision when the local entity has failed

to do so.

The Butte/Silver Bow Air Pollution Control Program and the

associated local ordinances, resolutions and stipulations are also

enforceable by the MDHES, if the BSHD fails to administer the program.

Since the program has been approved by the MBHES in accordance with

Section 75-2-301 of the Montana Clean Air Act and effectuated by a

MBHES order, and since the MDHES can enforce MBHES orders, the MDHES

has independent enforcement powers. Enforcement provisions are found in

the Clean Air Act of Montana, sections 75-2-401-429, Montana Code

Annotated.

The emission limits for Montana Resources, Inc. are enforceable by

the MDHES through Air Quality Permit #1749-05 with a final modification

date of January 5, 1994. Section 75-2-401 of the Montana Clean Air Act

allows the MDHES to seek civil penalties for a violation of a permit

limitation. Administrative Rules of Montana (ARM) 16.8.1112 allows the

MDHES to revoke a permit for a violation of a permit limitation. These

regulations are contained in ARM 16.8.101 through 16.8.1602 and

violations of these rules are punishable by civil penalties in an

amount up to $10,000 per day and criminal penalties in an amount up to

$1,000 per day.

The Butte/Silver Bow Air Pollution Control Program was established

in accordance with the requirements of Section 75-2-301 of the Montana

Clean Air Act, as amended (1991). A stipulation between the MDHES and

the Butte/Silver Bow Council of Commissioners was signed on October 8,

1991 to delineate responsibilities and authorities between the MDHES

and the local authorities. On November 15, 1991, the MBHES issued a

board order effectuating the program. On March 20, 1992, the MBHES

approved the Butte PM10 plan and local program. The stipulation,

Board order, and ordinances were incorporated into the SIP on March 11,

1994 (59 FR 11550).

On May 20, 1994, the MBHES issued a Board order approving the Butte

PM10 contingency measures. The related regulation, air quality

permit, and the May 20, 1994 Board order were submitted to EPA in the

August 26, 1994 submittal as a revision to the Montana SIP.

The Butte/Silver Bow regulation is in effect now, as is the State's

permit modification for Montana Resources, Inc. (Air Quality Permit

#1749-05). The State of Montana has a program that will ensure that the

contingency measures and Montana Resources, Inc. emission limitations

contained in the Butte PM10 SIP are adequately enforced. EPA

believes that the State's and Butte's existing air enforcement program

will be adequate. The TSD for this action contains further information

on enforceability requirements, responsibilities, and a discussion of

the personnel and funding intended to support effective implementation

of the control measures.

III. Final Action

EPA is approving Montana's SIP revision, submitted by the Governor

with a letter dated August 26, 1994, for the Butte moderate PM10

nonattainment area. This submittal adequately addressed, for the Butte

moderate PM10 nonattainment area, PM10 contingency measures,

which were due on November 15, 1993, and revisions to the attainment

and maintenance demonstrations to incorporate new permit emission

limitations for Montana Resources, Inc.

EPA is publishing this action without prior proposal because the

Agency views this as a noncontroversial amendment and anticipates no

adverse comments. However, in a separate document in this Federal

Register publication, EPA is proposing to approve the SIP revision

should adverse or critical comments be filed. Under the procedures

established in the May 10, 1994 Federal Register (59 FR 24054), this

action will be effective May 22, 1995 unless, by April 21, 1995,

adverse or critical comments are received.

If such comments are received, this action will be withdrawn before

the effective date by publishing a subsequent final rule based on this

action serving as a proposed rule. EPA will not institute a second

comment period on this action. Any parties interested in commenting on

this action should do so at this time. If no such comments are

received, the public is advised that this action will be effective on

May 22, 1995.

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 a 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.

Approvals of SIP submittals under section 110 and subchapter I,

part D of the Clean Air Act do not create any new requirements, but

simply approve requirements that the State is already imposing.

Therefore, because the Federal SIP-approval does not impose any new

requirements, I certify that it does not have a significant impact on

small entities affected. Moreover, due to the nature of the Federal-

state relationship under the Clean Air Act, preparation of a regulatory

flexibility analysis would constitute Federal inquiry into the economic

reasonableness of state action. The Clean Air Act forbids EPA to base

its actions concerning SIPs on such grounds. Union Electric Co. v. U.S.

E.P.A., 427 U.S. 246, 256-66 (1976); 42 U.S.C. 7410(a)(2).

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 May 22, 1995. Filing a

petition for reconsideration by [[Page 15061]] 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 must be filed, and shall not postpone the

effectiveness of such rule or action. This action may not be challenged

later in proceedings to enforce its requirements (see section

307(b)(2)).

The Office of Management and Budget (OMB) has exempted this

regulatory action from E.O. 12866 review.

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Carbon monoxide,

Hydrocarbons, Incorporation by reference, Intergovernmental relations,

Nitrogen dioxide, Particulate matter, Reporting and recordkeeping

requirements, Sulfur dioxide, Volatile organic compounds.

Dated: February 17, 1995.

Jack McGraw,

Acting Regional Administrator.

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 BB--Montana

2. Section 52.1370 is amended by adding paragraph (c)(36) to read

as follows:

Sec. 52.1370 Identification of plan.

* * * * *

(c) * * *

(36) The Governor of Montana submitted PM10 contingency

measures for Butte, Montana in a letter dated August 26, 1994. This

submittal also contained revisions to the attainment and maintenance

demonstrations for the moderate PM10 nonattainment area SIP, due

to modifications made to the Air Quality Permit for Montana Resources,

Inc.

(i) Incorporation by reference.

(A) Board order issued on May 20, 1994 by the Montana Board of

Health and Environmental Sciences approving the amendments to the

Butte/Silver Bow Air Pollution Control Program regarding the PM10

contingency measure.

(B) Butte/Silver Bow Ordinance No. 468, effective May 20, 1994,

which addresses PM10 contingency measure requirements for liquid

de-icer application.

(ii) Additional material.

(A) Montana Department of Health and Environmental Sciences Air

Quality Permit #1749-05, as revised with a final modification date of

January 5, 1994, for Montana Resources, Inc.'s open pit copper and

molybdenum mine, crushing and milling operation, and concentrator.

* * * * *

[FR Doc. 95-7004 Filed 3-21-95; 8:45 am]

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