[Federal Register Volume 60, Number 55 (Wednesday, March 22, 1995)]
[Rules and Regulations]
[Pages 15056-15061]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-7004]



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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]
BILLING CODE 6560-50-P