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

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

 [Federal Register: January 27, 1995]
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.



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 Amendments<SUP>1 (``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.


    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.<SUP>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.

 
 

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