[Federal Register Volume 60, Number 18 (Friday, January 27, 1995)]
[Rules and Regulations]
[Pages 5313-5318]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-2017]



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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[MT23-1-6402a; FRL-5128-1]


Approval and Promulgation of Air Quality Implementation Plans; 
Montana; State Implementation Plan for East Helena SO2 
Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

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SUMMARY: EPA fully approves the State implementation plan (SIP) 
submitted by the State of Montana to achieve attainment of the primary 
National Ambient Air Quality Standards (NAAQS) for sulfur dioxide 
(SO2). The SIP was submitted by Montana to satisfy certain federal 
requirements for an approvable nonattainment area SO2 SIP for East 
Helena. The effect of EPA's final action is to make the East Helena 
Primary SO2 NAAQS SIP federally enforceable.

DATES: This final rule is effective March 28, 1995, unless adverse 
comments are received by February 27, 1995. If the effective date is 
delayed, timely notice will be published in the Federal Register.

ADDRESSES: Comments should be addressed to Meredith A. Bond, 8ART-AP, 
Environmental Protection Agency, Region VIII, 999 18th Street, Suite 
500, Denver, Colorado 80202-2405. 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; and Montana Department of Health and Environmental 
Sciences, Air Quality Bureau, Cogswell Building, Helena, Montana 59620-
0901; and U.S. EPA Air & Radiation Docket Information Center, 401 M 
Street, SW., Washington, DC 20460.

FOR FURTHER INFORMATION CONTACT: Meredith Bond at (303) 293-1764.

SUPPLEMENTARY INFORMATION:

I. Background

    East Helena, Montana, is a small community located about 5 miles 
east of the State capitol, Helena. The major industrial source 
affecting the SO2 concentrations in the ambient air is the Asarco, 
Incorporated, primary lead smelter. The following summarizes the 
regulatory history of the East Helena SO2 nonattainment area.
    On September 19, 1975, EPA approved the revision to the Montana SIP 
which sets forth a sulfur oxide control strategy to provide for 
attainment and maintenance of the SO2 NAAQS near Asarco in East 
Helena (40 FR 43216).
    The Clean Air Act Amendments of 1977 provided for non-attainment 
designations for areas violating the NAAQS. On March 3, 1978, EPA 
designated the East Helena area as nonattainment for SO2 based on 
historical ambient monitoring data [[Page 5314]] showing primary 
standard violations (43 FR 8962).
    Prior to this official SO2 nonattainment designation, the 
Montana Department of Health and Environmental Sciences (MDHES) and 
Asarco had been working on a plan to reduce SO2 emissions from the 
East Helena facility. The main focus of this plan was the construction 
of a double contact sulfuric acid plant to control SO2 emissions 
from the sintering process. Following construction of the acid plant in 
July 1977, SO2 concentrations in the rural areas around East 
Helena decreased dramatically. However, there were still violations 
being monitored at the Kennedy Park site.
    In response to the Part D SIP requirements of the 1977 CAA 
Amendments, on April 24, 1979, Montana submitted a SIP revision for the 
East Helena SO2 nonattainment area. This SIP revision identified 
the continued monitored violations as being caused by low-level 
emissions from three 110-foot stacks serving the smelter's blast 
furnace operations. The control strategy included replacing the three 
110-foot stacks with a single 425-foot stack (for which Asarco claimed 
stack height credit of 375 feet), and setting daily and six-hour 
emission limits on the new stack. On November 20, 1980, EPA 
conditionally approved the SIP revision (45 FR 76685). EPA's action was 
conditioned upon adequate demonstration of good engineering practice 
(GEP) stack height for the blast furnace stack, and revised dispersion 
modeling if GEP height was determined to be below 375 feet.
    Asarco completed a field tracer study demonstration in 1982, and 
subsequently proceeded to complete construction of its new stack based 
on the study results justifying a stack height of 375 feet as necessary 
to overcome the effects of downwash causing monitored ambient SO2 
violations near the smelter.
    On July 5, 1983, EPA proposed to approve the SIP and GEP 
demonstration as satisfying the conditional approval requirements (48 
FR 30696). But, final action was not taken due to pending litigation 
concerning the federal stack height regulations. As a result of this 
litigation, the federal stack height regulations were revised on July 
5, 1985. Among other things, these revisions changed the requirements 
for justifying stack heights above the formula height established in 40 
CFR 51.100(ii)(2). For this reason, several years later Asarco 
abandoned its efforts to take credit for the additional blast furnace 
stack height above formula height. EPA's stack height analysis and 
findings for the Asarco facility stacks are discussed further later in 
this document.
    The SIP was further revised with respect to East Helena in order to 
provide for a catalyst screening procedure at Asarco's acid plant. EPA 
approved this revision on May 1, 1984 (54 FR 18482).
    The 1990 Clean Air Act Amendments1 (``1990 Amendments''), 
effective November 15, 1990, reaffirmed the nonattainment designation 
of East Helena with respect to the primary and secondary SO2 
NAAQS, under section 107(d)(4)(B). See 56 FR 56706 (Nov. 6, 1991) and 
40 CFR 81.327 (specifying designation for East Helena). Section 191 
required that any state which was lacking an approved SIP for an area 
designated nonattainment with respect to the national primary ambient 
air quality standard for SO2 must resubmit a plan meeting the 
requirements of the amended Act within 18 months of enactment of the 
amendments, thus by May 15, 1992. For the secondary SO2 NAAQS SIP 
for East Helena, EPA established November 15, 1993, as the submittal 
due date in an action published in the Federal Register on October 7, 
1993 (58 FR 52237).

    \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 (``the 
Act''). The Clean Air Act is codified, as amended, in the U.S. Code 
at 42 U.S.C. Sections 7401, et seq.
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    The air quality planning requirements for SO2 nonattainment 
areas are set out in subparts 1 and 5 of part D of title I of the 
Act.2 The amended Clean Air Act requires nonattainment area SIP 
submittals to contain, among other things, provisions to assure that 
reasonable available control measures (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) 
are implemented, and that provide for attainment of the primary 
SO2 standards within 5 years of enactment of the 1990 Amendments, 
or November 15, 1995 (see Sections 172(c) and 192(b) of the Act). EPA 
has issued detailed guidance that describes the Agency's preliminary 
interpretations regarding SO2 nonattainment area SIP requirements. 
[57 FR 13498 (April 16, 1992) and 57 FR 18070 (April 28, 1992) 
(hereafter called the ``General Preamble'')]. 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 today's action and the 
supporting rationale.

    \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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II. This Action

    The primary SO2 NAAQS SIP for East Helena was developed by the 
MDHES in consultation with Asarco, the major SO2 source in East 
Helena. The State's efforts have been coordinated with EPA to ensure 
compliance with SIP requirements. The Montana Board of Health and 
Environmental Sciences (MBHES) approved a stipulation between the MDHES 
and Asarco on March 18, 1994, to limit SO2 emissions from that 
company's lead smelting operations. This binding agreement was 
submitted to EPA on March 30, 1994, as part of a revision of the 
Montana SIP. This SIP revision addresses only the 24-hour and annual 
primary SO2 NAAQS; Montana will address the 3-hour secondary 
SO2 NAAQS in a forthcoming submittal. Hence, this action addresses 
only the primary SO2 NAAQS.
    Section 110(k) of the Act sets out provisions governing EPA's 
review of SIP submittals (see 57 FR 13565-66). In this action, EPA is 
approving the primary SO2 NAAQS SIP revision for the East Helena, 
Montana, nonattainment area which was due on May 15, 1992, and was 
submitted by the Governor of Montana on March 30, 1994. EPA is also 
approving the stack height demonstrations for the Asarco, East Helena, 
primary lead smelter. EPA believes that the East Helena plan meets the 
applicable requirements of the Act.
    Since the East Helena Primary SO2 NAAQS SIP was not submitted 
by May 15, 1992, as required by section 191 of the Act, EPA made a 
finding that the State failed to submit the SIP, pursuant to section 
179 of the Act, and notified the Governor in a letter dated June 16, 
1992. See 57 FR 48614 (October 27, 1992). After the East Helena Primary 
SO2 NAAQS SIP was submitted on March 30, 1994, EPA found the 
submittal complete pursuant to section 110(k)(1) of the Act and 
notified the Governor accordingly in a letter dated May 12, 1994. This 
completeness determination corrected the State's deficiency and, 
therefore, terminated the sanctions clock under section 179 of the Act.

A. Analysis of State Submission

1. Procedural Background
    The Act requires States to observe certain procedural requirements 
in [[Page 5315]] 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(1) of the Act 
similarly provides that each revision to an implementation plan 
submitted by a State under the Act must be adopted by such State after 
reasonable notice and public hearing. The EPA also must determine 
whether a submittal is complete and therefore warrants further EPA 
review and action (see section 110(k)(1) and 57 FR 13565). The EPA's 
completeness criteria for SIP submittals are set out at 40 CFR Part 51, 
Appendix V. 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.

    \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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    To entertain public comment on the implementation plan for East 
Helena, the State of Montana, after providing adequate notice, held a 
public hearing on March 18, 1994, to address the stipulation between 
the MDHES and Asarco, and the East Helena primary SO2 NAAQS SIP. 
Following the public hearing, the stipulation and SIP were adopted by 
the State. The Governor of Montana submitted the SIP to EPA on March 
30, 1994. The SIP submittal was reviewed by EPA to determine 
completeness in accordance with the completeness criteria set out at 40 
CFR Part 51, Appendix V. The submittal was found to be complete, and a 
letter dated May 12, 1994, was forwarded to the Governor indicating the 
completeness of the submittal and the next steps to be taken in the 
review process.
2. Accurate Emission 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 emission inventory also should include a 
comprehensive, accurate, and current inventory of allowable emissions 
in the area.
    The MDHES identified two major sources of SO2 in the East 
Helena area: the Asarco Smelter complex and the Ash Grove cement plant. 
Emission inventory information for the Ash Grove Kiln stack was derived 
from an engineering calculation to determine potential SO2 
emissions. Assuming all heat input to the kiln is supplied by 6% sulfur 
coke, a potential emission rate of 2.7 tons SO2/day was used for 
this facility in this SIP revision. Actual SO2 emissions for this 
source are approximately 1.0 ton per day.
    A detailed SO2 emission inventory of the Asarco smelter 
facility was conducted in the fall of 1991. A complete testing protocol 
was approved by EPA along with the final emission inventory report. The 
report provided a complete and accurate SO2 emission inventory of 
the entire facility for use in dispersion modeling studies.
    In general, the SO2 emission sources were separated into three 
major categories: Point sources, volume sources, and fugitive sources. 
The results of the point source tests confirmed Asarco's three major 
sources of SO2 emissions to be the Sinter Plant Baghouse stack, 
Acid Plant stack, and Blast Furnace Baghouse stack. Volume and fugitive 
sources were also quantified.
    The MDHES also maintains an annual SO2 emission inventory for 
the Asarco facility. This inventory does not include all sources that 
were measured in the field sampling study, but does include the major 
sources of SO2 emissions. Totals for 1990 (including only the 
three major point sources) were 17,491.0 tpy; totals for 1991 (with 
building volume and fugitive area sources included) were 18,031.7 tpy. 
Thus, annual SO2 emissions for the Asarco facility are 
approximately 18,000 tpy. For the Ash Grove kiln stacks, emissions for 
the same years were less than 280 tpy.
    EPA is approving the emissions inventory because it is 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 Act. For 
further details see the TSD.
3. RACM (Including RACT)
    As noted, the initial SO2 nonattainment areas must submit 
provisions to assure that RACM (including RACT) are implemented as 
expeditiously as possible (see section 172(c)(1)). The General Preamble 
contains a detailed discussion of EPA's interpretation of the RACM 
(including RACT) requirement (see 57 FR 13547 and 13560-13561), and 
defines RACT for SO2 as that control technology which is necessary 
to achieve the NAAQS.
    The Asarco, East Helena, primary lead smelter was identified as the 
major source of the SO2 nonattainment problem in East Helena. The 
control strategy includes setting operational SO2 emission limits 
for several of the major emission points of the Asarco facility.
    Asarco developed a set of emissions parameters for combined 
emissions from the two largest SO2 emission points, the sinter and 
blast furnace stacks, in order to provide maximum operating flexibility 
while still protecting the NAAQS. The set of compliance parameters for 
combined emissions from the Blast Furnace Stack and Sinter Plant Stack 
consists of the following relationships:

for:

022.93, B=29.64-(0.180) S
22.9354.54, B=38.74-(0.577) S
54.5460.27, B=76.60-(1.271) S

where:

B=Daily emissions of SO2 from the Blast Furnace Stack in tons per 
calendar day
S=Daily emissions of SO2 from the Sinter Plant Stack in tons per 
calendar day

    In addition to the compliance parameters for combined emissions 
from the sinter and blast furnace stacks, the March 18, 1994, 
stipulation also sets absolute SO2 emission limitations for the 
sinter and blast furnace stacks at 60.27 tons per calendar day and 
29.64 tons per calendar day, respectively. Daily emissions of SO2 
from the Acid Plant Stack shall not exceed 4.30 tons per calendar day. 
SO2 emissions from the Concentrate Storage and Handling Building 
Stack (including the exhaust from the new Sinter Plant Ventilation 
System baghouse) shall not exceed 46.00 pounds per hour or 0.552 tons 
per calendar day. All of these emission limits, including the 
compliance parameters for the combined emissions of the sinter and 
blast furnace stacks, were effective September 1, 1994.
    Two additional emission limitations on minor stack sources at the 
Asarco facility take effect June 30, 1995: SO2 emissions from the 
Crushing Mill Baghouse Stacks #1 and #2 shall not exceed 0.19 and 0.37 
tons per calendar day, respectively.
    The stipulation details the use of continuous emission monitoring 
systems to determine compliance with the emission limitations for the 
sinter plant stack, blast furnace stack, and acid plant stack. Emission 
testing provisions for the remaining stacks are also specified.
    Provisions have also been incorporated into the stipulation to 
insure that sulfur dioxide emissions from miscellaneous volume and 
fugitive sources do not increase beyond their current levels. Those 
provisions include: limiting fugitive emissions of 
[[Page 5316]] SO2 from the Sinter (D&L) Building by restricting 
openings to the building enclosure; maintaining and operating all 
processes and systems within the Cottrell Penthouse, Mist Precipitator 
Building, and Pump Tank Building such that conditions which contribute 
to volume source SO2 emissions from these sources are not 
significantly worsened compared to conditions existing during the 
preparation of the January 20, 1992, emission inventory report; and 
maintaining and operating all processes and systems associated with the 
Acid Plant Scrubber Towers such that conditions which contribute to 
volume source SO2 emissions from this source are not significantly 
worsened compared to conditions existing during the preparation of the 
January 20, 1992, emission inventory report.
    A more detailed discussion of the control strategy can be found in 
the TSD for this action. EPA has reviewed the State's documentation and 
concluded that it adequately justifies the control measures to be 
implemented. The implementation of Montana's SO2 nonattainment 
plan will result in the attainment of the primary SO2 NAAQS by 
November 15, 1995. By this action EPA is approving the East Helena 
primary SO2 plan's RACM (including RACT) in its entirety, noting 
that additional dispersion modeling and control strategy evaluation 
will be necessary in the future to address the secondary, 3-hour 
standard.
4. Demonstration
    The initial SO2 nonattainment areas are required to submit a 
demonstration (including air quality modeling) showing that the plan 
will provide for attainment as expeditiously as practicable, but no 
later than November 15, 1995. EPA-approved dispersion models ISCST and 
RTDM were used to predict ambient SO2 concentrations around the 
Asarco facility. The primary SO2 NAAQS are 365 micrograms per 
cubic meter (g/m\3\) (0.14 parts per million (ppm)), averaged 
over a 24-hour period and not to be exceeded more than once per year, 
and 80 g/m\3\ (0.03 ppm) annual arithmetic mean (see 40 CFR 
50.4). The demonstration for East Helena indicates that the primary 
SO2 NAAQS will be attained by November 15, 1995. For a more 
detailed description of the attainment demonstration and the control 
strategies used, see the TSD for this action.
5. Enforceability Issues
    All measures and other elements in the SIP must be enforceable by 
the State and EPA (see sections 172(c)(6) and 110(a)(2)(A) of the Act 
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). Nonattainment area 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) of the Act).
    The specific control measure contained in the SIP are addressed 
above in section 3, ``RACM (including RACT).'' The March 18, 1994, 
stipulation between the MDHES and Asarco 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. The Montana Clean 
Air Act grants authority to the MDHES to enforce orders of the Board 
(section 75-2-112, Montana Code Annotated (MCA)). Sections 75-2-412 and 
75-2-413, MCA, authorize the MDHES to seek criminal and civil penalties 
for violations of any Board order in the amount of $10,000.00 per day 
of violation, respectively. In addition, Section 75-2-431, MCA, 
authorizes the MDHES to seek noncompliance penalties for any violation 
of a Board order. Noncompliance penalties shall be no less than the 
economic value which a delay in compliance may have for the owner of 
such a source, including the capital costs of compliance and debt 
service over a normal amortization period (not to exceed ten years of 
operation) and maintenance costs foregone as a result of noncompliance.
    EPA believes that the State's existing air enforcement program will 
be adequate to ensure implementation of this SIP revision. The TSD for 
this action contains further information on enforceability 
requirements, responsibilities, and resources intended to support 
effective implementation of the control measures.
6. Reasonable Further Progress
    Section 171(l) of the amended Act defines RFP as ``such annual 
incremental reductions in emissions of the relevant air pollutant as 
are required by [part D] or may reasonably be required by EPA for the 
purpose of ensuring attainment of the applicable national ambient air 
quality standard by the applicable date.'' As discussed in the General 
Preamble, for SO2, there is usually a single ``step'' between pre-
control nonattainment and post-control attainment. Therefore, for 
SO2, with its discernible relationship between emissions and air 
quality and significant and immediate air quality improvements, RFP is 
construed as ``adherence to an ambitious compliance schedule.''
    Asarco became responsible for the reporting requirements outlined 
in the SIP after July 1, 1994. The emission and process limitations 
outlined above became effective on September 1, 1994. These timelines 
allow Asarco sufficient opportunity to implement the control strategy, 
and to gain operating experience before the requirements become 
effective. The emission limitations went into effect September 1, 1994, 
a date far in advance of the November 15, 1995 attainment date. EPA 
concurs that this program constitutes adherence to an ambitious 
compliance schedule and therefore demonstrates reasonable further 
progress.
7. Contingency Measures
    Section 172(c)(9) of the amended Act defines contingency measures 
as measures in a SIP which are to be implemented if an area fails to 
make RFP or fails to attain the NAAQS by the applicable attainment 
date. Contingency measures become effective without further action by 
the State or EPA, upon determination by EPA that the area has failed to 
either make reasonable further progress or to attain the SO2 NAAQS 
by the applicable statutory deadline. For SO2 programs, EPA 
interprets ``contingency measures'' to mean that the State agency has a 
comprehensive program to identify sources of violations of the SO2 
NAAQS and to undertake an aggressive follow-up for compliance and 
enforcement, including expedited procedures for establishing 
enforceable consent agreements pending the adoption of revised SIP's. 
(See 57 FR 13547, April 16, 1992.)
    The East Helena control strategy is based upon a dispersion 
modeling analysis which indicates that the Primary SO2 NAAQS will 
be protected. The use of continuous emission monitoring systems will 
ensure that the emission limitations in the plan are not exceeded. In 
addition, a compliance network of ambient air monitoring stations will 
be maintained around the smelter at locations associated with predicted 
maximum concentrations. This monitoring system should quickly identify 
any violations of the NAAQS, if they should occur.
    If violations should occur, the MDHES would immediately begin 
negotiations with Asarco to reach agreement on control measures to 
[[Page 5317]] correct the problem. Asarco would then implement those 
measures to assure compliance as expeditiously as possible. 
Additionally, the MDHES has emergency powers under Section 75.2.402 of 
the Montana Clean Air Act to require curtailment of a source if the 
source is causing imminent danger to human health or safety.

III. Stack Height Analysis

A. Background

    On February 8, 1982 (47 FR 5864), EPA promulgated final regulations 
limiting stack height credits and other dispersion techniques as 
required by Section 123 of the CAA. These regulations were challenged 
in the U.S. Court of appeals for the D.C. Circuit by the Sierra Club 
Legal Defense Fund, Inc., the Natural Resources Defense Council, Inc., 
and the Commonwealth of Pennsylvania in Sierra Club v. EPA. On October 
11, 1983, the court issued its decision ordering EPA to reconsider 
portions of the stack height regulations, revising certain portions and 
upholding other portions.
    On February 28, 1984, the electric power industry filed a petition 
for a writ of certiorari with the U.S. Supreme Court. On July 2, 1984, 
the Supreme Court denied the petition, and on July 18, 1984, the Court 
of Appeals mandate was formally issued, implementing the court's 
decision and requiring EPA to promulgate revisions to the stack height 
regulations within six months. The promulgation deadline was ultimately 
extended to June 27, 1985.
    Revisions to the stack height regulations were proposed on November 
9, 1984 (49 FR 44878), and promulgated on July 8, 1985 (50 FR 27892). 
The revisions redefined a number of specific terms including 
``excessive concentrations,'' ``dispersion techniques,'' ``nearby,'' 
and other important concepts, and modified some of the bases for 
determining good engineering practice (GEP) stack height.
    Pursuant to section 406(d)(2) of the CAA, all States were required 
to: (1) Review and revise, as necessary, their SIPs to include 
provisions that limit stack height credit and dispersion techniques in 
accordance with the revised regulations and (2) review all existing 
emission limitations to determine whether any of these limitations have 
been affected by stack height credits above GEP or any other dispersion 
techniques. For any limitations so affected, States were to prepare 
revised limitations consistent with their revised SIPs. All SIP 
revisions and revised emission limits were to be submitted to EPA 
within 9 months of the EPA stack height regulations promulgation.
    Subsequently, EPA issued detailed guidance on carrying out the 
necessary reviews. For the review of emission limitations, States were 
to prepare inventories of stacks greater than 65 meters in height and 
sources with emissions of sulfur dioxide (SO2) in excess of 5,000 
tons per year. These limits correspond to the de minimis stack height 
and the de minimis SO2 emission exemption from prohibited 
dispersion techniques. These sources were then subjected to detailed 
review for conformance with the revised regulations. State submissions 
were to contain an evaluation of each stack and source in the 
inventory.
    Subsequent to the July 8, 1985 promulgation, the stack height 
regulations were again challenged in NRDC v. Thomas, 838 F. 2d 1224 
(D.C. Cir. 1988). On January 22, 1988, the U.S. Court of Appeals for 
the D.C. Circuit issued its decision affirming the regulations for the 
most part, but remanding three provisions to the EPA for 
reconsideration. These are: Grandfathering stack height credits for 
sources that raise their stacks prior to October 1, 1983, up to the 
height permitted by GEP formula height (40 CFR 51.100 (kk)(21)), 
dispersion credit for sources originally designed and constructed with 
merged or originally designed and constructed with merged or multi-flue 
stacks, (40 CFR 51.100 (hh)(2)(ii)(A)), and grandfathering credit for 
the refined (H + 1.5 L) formula height for sources unable to show 
reliance on the original (2.5H) formula (40 CFR 51.100 (ii)(2)).

B. State of Montana Submissions

    EPA promulgated approval of a SIP revision which revised the 
Administrative Rules of Montana governing stack height and dispersion 
techniques on June 7, 1989 (54 FR 24334). In that same action, EPA 
approved Montana's stack height demonstration analyses with the 
exception of the Asarco East Helena lead smelter facility stacks. This 
is the first time that EPA is taking action on the Asarco stacks.

C. Asarco, East Helena Stack Height Demonstration

    EPA received a stack height review from Montana with a letter dated 
November 25, 1985, and a subsequent submittal dated January 28, 1986. 
With regard to the Asarco stack heights, the State found that no 
existing emission limitations were affected by stack height credits 
above GEP or any other dispersion technique prohibited by EPA 
regulations.
    EPA has determined that Montana's inventory of the Asarco facility 
at East Helena is complete and has carefully reviewed the State's 
findings. EPA concurs with those findings, which are summarized in the 
table below. A detailed discussion of the Asarco stack height analysis 
can be found in the TSD for this action.

------------------------------------------------------------------------
                             Actual                                     
                             stack                                 GEP  
        Stack I.D.           height    Applicable GEP formula     height
                              (m)                                  (m)  
------------------------------------------------------------------------
Sinter....................      128  Grandfathered (1939)......  .......
Blast Furnace.............      130  de minimis................       65
Zinc Furnace..............      107  (*)                             (*)
------------------------------------------------------------------------
*Source is shut down. New permit will be required to reopen zinc plant. 

IV. Final Action

    EPA is approving the East Helena primary SO2 NAAQS SIP 
submitted to EPA on March 30, 1994. Among other things, the State of 
Montana has demonstrated that the East Helena SO2 nonattainment 
area will attain the primary SO2 NAAQS by November 15, 1995. EPA 
is also approving stack height demonstrations for the Asarco, East 
Helena, primary lead smelter.
    Because EPA considers this action noncontroversial and anticipates 
no adverse comments, this final approval is made without prior 
proposal. This action will be effective March 28, 1995. However, if 
adverse comments are received by February 27, 1995, then EPA would 
withdraw this final approval action and this notice would instead stand 
as a proposed rule. EPA would then address the comments in a subsequent 
final promulgation notice.
    Nothing in this action should be construed as permitting, allowing 
or establishing a precedent for any future request for revision to any 
SIP. Each request for revision to any SIP shall be considered 
separately in light of specific technical, economic, and environmental 
factors, and in relation to relevant statutory and regulatory 
requirements.
    The OMB has exempted this regulatory action from review under 
Executive Order 12866.
    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 [[Page 5318]] include small businesses, small not-for-
profit enterprises, and government entities with jurisdiction over 
populations of less than 50,000.
    SIP approvals under section 110 and Subchapter I, Part D of the 
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 a substantial number of 
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 Act, petitions for judicial review 
of this action must be filed in the United States Court of Appeals for 
the appropriate circuit by March 28, 1995. Filing a petition for 
reconsideration by the Administrator of this final rule does not affect 
the finality of this rule for the purposes of judicial review nor does 
it extend the time within which a petition for judicial review may be 
filed, and shall not postpone the effectiveness of such rule or action. 
This action may not be challenged later in proceedings to enforce its 
requirements. (See Act, section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental Protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Reporting and recordkeeping 
requirements, Sulfur dioxide.

    Dated: December 14, 1994.
William P. Yellowtail,
Regional Administrator.

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

PART 52--[AMENDED]

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

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

Subpart BB--Montana

    2. Section 52.1370 is amended by adding paragraph (c)(37) to read 
as follows:


Sec. 52.1370  Identification of plan.

* * * * *
    (c) * * *
    (37) The Governor of Montana submitted a SIP revision meeting the 
requirements for the primary SO2 NAAQS State Implementation Plan 
(SIP) for the East Helena, Montana nonattainment area with a letter 
dated March 30, 1994. The submittal was to satisfy those SO2 
nonattainment area SIP requirements due for East Helena on May 15, 
1992.
    (i) Incorporation by reference.
    (A) Stipulation signed March 15, 1994, between the Montana 
Department of Health and Environmental Sciences (MDHES) and Asarco, 
Incorporated, which specifies SO2 emission limitations and 
requirements for the company's primary lead smelter located in East 
Helena, MT.
    (B) Board order issued on March 18, 1994, by the Montana Board of 
Health and Environmental Sciences approving and adopting the control 
strategy for achieving and maintaining the primary SO2 NAAQS in 
the East Helena area.

[FR Doc. 95-2017 Filed 1-26-95; 8:45 am]
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