Approval and Promulgation of Implementation Plans; State of Iowa

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[IA 031-1031; FRL-5875-5]

Approval and Promulgation of Implementation Plans; State of Iowa

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to approve the State Implementation Plan

(SIP) submitted by the state of Iowa to achieve attainment of the

primary National Ambient Air Quality Standard (NAAQS) for sulfur

dioxide (SO2) for Muscatine County, Iowa. The SIP was

submitted to satisfy the requirements of section 110 and part D of

title I of the Clean Air Act (Act), and regulates certain sources of

SO2 emissions in Muscatine, Iowa. The effect of the EPA's

proposed action is to make this revision to the Iowa SIP federally

enforceable.

DATES: Comments must be received on or before September 15, 1997.

ADDRESSES: Comments may be mailed to Wayne Kaiser, Environmental

Protection Agency, Air Planning and Development Branch, 726 Minnesota

Avenue, Kansas City, Kansas 66101.

FOR FURTHER INFORMATION CONTACT: Wayne Kaiser at (913) 551-7603.

SUPPLEMENTARY INFORMATION:

I. Background

On March 10, 1994, the EPA published a document in the Federal

Register (59 FR 11193) designating a portion of Muscatine County, Iowa,

nonattainment for SO2. Additional information on the events

leading to nonattainment designation are contained in the Technical

Support Document (TSD) which accompanied that document.

Areas designated nonattainment are subject to section 110 and part

D of title I of the Act. On June 13, 1996, and April 25, 1997, the

state of Iowa submitted information satisfying these requirements. An

evaluation of the adequacy of this submittal with the Federal

requirements is discussed below.

II. Description and Analysis of State Submittal

In 1991 and 1992 there were violations of the primary

SO2 NAAQS at one of three state air monitors in Muscatine,

Iowa. This resulted in designation of a portion of Muscatine County as

nonattainment in 1994. The state determined that there were two major

emission sources contributing to the violations of the NAAQS. They were

Grain Processing Corporation (GPC), a wet grain milling facility, and

Muscatine Power and Water (MPW), a municipal power plant. In the course

of modeling the impacts of these emission sources, it was also

determined that a third source, Monsanto Corporation, contributed to a

modeled violation of the SO2 NAAQS in the vicinity of its

own facility.

The state of Iowa's Department of Natural Resources negotiated

emission reductions with GPC, MPW, and Monsanto. The reductions were

incorporated into revised construction permits. These permits have been

submitted as a part of the section 110 SIP revision and thus will be

federally enforceable when approved by the EPA.

The normal process for establishing a control strategy for an area

where a NAAQS violation has occurred is to conduct an air dispersion

modeling analysis to determine the degree of emissions reductions

required by the sources contributing to the monitored violations.

The NAAQS violations occurred at the Musser Park monitor, which is

located north of and nearest to the GPC facility. Two additional

monitors, one located further north of the sources, and one located to

the south near MPW, have never recorded any violations of the NAAQS.

Dispersion modeling performed by the state using the EPA's

Industrial Source Complex (ISC) model significantly under predicted

monitored values at the Musser Park monitor, but was highly accurate at

the other downwind monitoring site. Consequently, the state initially

used an alternative methodology, roll-back analysis, to estimate

emission rates needed to attain the NAAQS at the Musser Park monitoring

site. A roll-back analysis takes a monitored ambient exceedance

recorded during a specific set of facility operating conditions and

determines the amount of the exceedance due to each of the source's

SO2 emitting operations in use at that time. The estimates

are then linearly ``rolled back'' to acceptable SO2 emission

limits which provide for attainment of the NAAQS under that set of

operating conditions. Ultimately, the state, GPC, and MPW negotiated

reductions of allowable emissions of 24 percent and 60 percent,

respectively, and reductions of actual emissions of 4 percent and 13

percent, respectively. These emission reductions were incorporated into

revised construction permits for each source. These permits are

proposed for approval as part of this

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SIP revision and thus will be federally enforceable. The TSD for this

action contains further information on the modeling analysis and the

establishment of the final emission limits.

Although the ISC model was not sufficiently accurate to be the

basis for the control strategy at GPC and MPW, it was judged to be

reliable for predicted emissions in the vicinity of the Monsanto

facility. Modeling here indicated one small area of nonattainment on

plant property to which the public had access. Monsanto agreed to

accept emission limits and operating conditions in its permits to

eliminate the modeled exceedances of the SO2 NAAQS.

The emission limits imposed upon the sources are contained in the

following permits:

GPC Permits dated September 18, 1995: #95-A-374; Boilers 1,2,3,5,6,7,

#74-A-015-S; Source 97, Wet Milling No. 3 Germ Drier, #79-A-194-S;

Source 15, Wet Milling Nos. 1 and 2 Germ Driers, #79-A-195-S; Source

126, Wet Milling No. 4 Germ Drier. Permit #95-A-374 contains the

requirement for the installation of a continuous emission monitor (CEM)

on the stack servicing the permitted boilers.

MPW Permits dated September 14, 1995: #74-A-175-S; Boiler 7, #95-A-373;

Boiler 8. Permit #74-A-175 requires the installation of a CEM on boiler

stack 7. The CEMs provide for continuous measurement of SO2

emissions and the subsequent determination of compliance with the

permit emission limits. All permits contain the state's standard

notification, recordkeeping, and reporting requirements.

Monsanto Permits dated July 18, 1996: #76-A-265-S3; B-6 Boiler, and

#76-A-161-S3; B-7 Boiler.

III. Nonattainment Plan Provisions (Part D, Section 172(c))

The following discusses how the submission complies with the

pertinent provisions of the General Preamble for Implementation of

title I of the 1990 Amendments and the SO2 Guideliine

Document, as well as section 172(c) of the Act, which sets forth the

requirements for part D SO2 SIPs.

Section 172(c)(1)--In General. The plan complies with the

requirements to implement reasonably available control measures by

providing for expeditious attainment of the SO2 NAAQS

through the emission limits imposed on the sources by enforceable

permits.

Section 172(c)(2)--Reasonable Further Progress (RFP). 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 reasonable be required by the 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 (57 FR 13547), there is usually a single ``step''

between precontrol nonattainment and postcontrol attainment. Therefore,

for SO2, with its discernible relationship between emissions

and air quality and significant and immediate air quality improvement,

RFP is construed as ``adherence to an ambitious compliance schedule.''

The state has met the requirement to implement reasonably available

control measures and RFP by providing for expeditious attainment of the

SO2 NAAQS through the establishment of emissions limits and

operating restrictions imposed on the sources by the state construction

permits submitted as part of the state plan. Implementation plans

required under section 191(a) shall provide for attainment as

expeditiously as practicable but no later than five years from the date

of the nonattainment designation, in this case by March 1999. However,

the state permits required compliance (and attainment) by March 15,

1996. The sources met this compliance date, and the EPA believes that

this date was as expeditious as practicable.

Section 172(c)(3)--Inventory. This section 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.

A detailed emission inventory was included in the states

submittal. In order to better quantify actual emission from the 100

``nontraditional'' sources at GPC, source testing was conducted on two

occasions on a number of representative emission points. In addition to

the four major sources in the area, an emissions inventory was obtained

for modeling purposes from three additional minor sources in Muscatine,

and from 36 sources outside of Muscatine but within 50 kilometers.

Section 172(c)(5)--Permits for New and Modified Major Stationary

Sources. Section 172(c)(5) and section 173 of the amended Act contains

SIP requirements for state construction permitting programs. Any new or

modified major stationary source constructed in a nonattainment area

must comply with the state submitted and federally approved New Source

Review (NSR) Program. The state has an approved NSR program. However,

revisions were required to make the state rules compliant with the 1990

Amendments. The state adopted revisions and the EPA approved them in

Federal Register documents dated June 23, 1995, and October 30, 1995.

The EPA action proposing approval of the state's emission offset rule

has been published and a final action is pending.

Section 172(c)(6)--Other Measures. This section states that SIP

provisions shall include enforceable emission limitations, and such

other control measures, means or techniques, as well as schedules and

timetables for compliance as may be necessary, to provide for

attainment by the applicable attainment date.

The state SIP provides for expeditious attainment of the

SO2 NAAQS through the emission limits and operating

restrictions that are set forth in the permits issued by the state. The

emission reductions contained in these documents should ensure that the

area continues to attain the NAAQS.

Section 172(c)(7)--Compliance with Section 110(a)(2). This section

contains general requirements for nonattainment plans. The state has

met these requirements. The SIP contains enforceable permits which

ensure attainment of the NAAQS. The state has committed to continue its

existing ambient monitoring network; it has an approved parts C and D

permit program (final approval of the state's emission offset rule is

pending); and it has authority to prevent construction of a source

which will contribute significantly to nonattainment in, or interfere

with maintenance by, any other state with respect to the NAAQS. It also

has demonstrated it has adequate personnel, funding, and authority

under state law to carry out the provisions of the SIP. With respect to

section 110(a)(2)(K), under which the EPA generally requires modeling

in the case of SO2 and other pollutants (to demonstrate

attainment as required by other provisions of section 110(a) and part

D), the EPA notes that the ISC model used by the state has been shown

to under predict ambient SO2 concentrations at the Musser

Park monitor on known exceedance days. Therefore, as described in more

detail above, a negotiated reduction of the permitted emission limits

was established.

Section 172(c)(8)--Equivalent Techniques. This section provides

that

[[Page 43683]]

the EPA may allow the state to use equivalent modeling, emission

inventory, and planning procedures in its SIP unless the EPA determines

they are less effective than procedures approved by the Administrator.

Since attainment of the SO2 NAAQS could not be demonstrated

for all portions of the nonattainment area by modeling (for technical

reasons described above and in more detail in the TSD), reductions in

both allowable and actual limits were determined for the affected

sources based generally on rollback calculations. The EPA believes that

this procedure is no less effective than other procedures approved by

the Administrator since it results in enforceable reductions in both

potential and actual emissions. In addition, although not a basis for

approval of the attainment demonstration, the EPA notes that no

monitored violations of the NAAQS have been recorded since the

reductions have been implemented.

Section 172(c)(9)--Contingency Measures. For SO2

programs, the 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

adoption of revised SIPs.

The state has a comprehensive program to identify sources of

violations of the SO2 NAAQS and to undertake an aggressive

follow-up for compliance and enforcement. The state has statutory

authority to address any exceedances and resultant violations of the

NAAQS that may be identified.

The state will continue to maintain the network of the three

SO2 ambient air monitoring stations in the nonattainment

area. The state is committed to quickly identifying when exceedances

occur and evaluating which sources may be contributing to such

occurrences. Direct source monitoring, using CEMs as required in the

permits issued to MPW and GPC under this plan, is designed to ensure

that the emissions limitations in the permit are not exceeded.

Reporting requirements established in those permits provide the state

with a mechanism to consistently monitor the operations of those

sources.

Section 176(c)--Conformity. The EPA promulgated final general

conformity regulations on November 30, 1993. These regulations require

the states to adopt general conformity provisions in the SIPs for areas

designated nonattainment or subject to a maintenance plan approved

under section 175A of the Act. The state submitted its general

conformity SIP, which the EPA approved on October 25, 1995. The state

is not subject to the transportation conformity requirements.

The state complied with the procedural requirements for submittal

of SIPs pursuant to sections 110(a) and 110(l). The state provided for

public notice and comment as required. The permits were approved by the

Iowa Environmental Protection Commission. The SIP and related

documentation was submitted by the governor's designee to the EPA on

June 13, 1996, and April 25, 1997.

The SIP submittal was reviewed by the EPA to determine completeness

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

appendix V. The submittal was found complete and the state was so

notified by an EPA letter dated July 16, 1996.

IV. Proposed Action

The EPA is proposing to approve a revision to the state SIP which

incorporates emission restrictions and limitations on major

SO2 sources in Muscatine, Iowa, for the purpose of assuring

attainment and maintenance of the SO2 NAAQS. The enforceable

permit conditions have been in effect since March 15, 1996. There have

been no exceedances of the NAAQS since September 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 the SIP shall be

considered separately in light of specific technical, economic, and

environmental factors, and in relation to relevant statutory and

regulatory requirements.

V. Administrative Requirements

A. Executive Order 12866

The Office of Management and Budget has exempted this regulatory

action from Executive Order 12866 review.

B. Regulatory Flexibility Act

Under the Regulatory Flexibility Act, 5. U.S.C. 600 et seq., the

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, the EPA may certify that the rule will not have a

significant impact on a substantial number of small entities. Small

entities include small businesses, small not-for-profit enterprises,

and government entities with jurisdiction over populations of less than

50,000.

SIP approvals under section 110 and subchapter I, part D of the CAA

do not create any new requirements but simply approve requirements that

the state is already imposing. Therefore, because the Federal SIP

approval does not impose any new requirements, the Administrator

certifies that it does not have a significant impact on any small

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

relationship under the CAA, preparation of a regulatory flexibility

analysis would constitute Federal inquiry into the economic

reasonableness of state action. The CAA forbids the 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 (S.Ct. 1976); 42 U.S.C. 7410(a)(2)).

C. Unfunded Mandates

Under section 202 of the Unfunded Mandates Reform Act of 1995

(``Unfunded Mandates Act''), signed into law on March 22, 1995, the EPA

must prepare a budgetary impact statement to accompany any proposed or

final rule that includes a Federal mandate that may result in estimated

costs to state, local, or tribal governments in the aggregate; or to

private sector, of $100 million or more. Under section 205, the EPA

must select the most cost-effective and least burdensome alternative

that achieves the objectives of the rule and is consistent with

statutory requirements. Section 203 requires the EPA to establish a

plan for informing and advising any small governments that may be

significantly or uniquely impacted by the rule.

The EPA has determined that the approval action proposed does not

include a Federal mandate that may result in estimated costs of $100

million or more to either state, local, or tribal governments in the

aggregate, or to the private sector. This Federal action approves

preexisting requirements under state or local law, and imposes no new

requirements. Accordingly, no additional costs to state, local, or

tribal governments, or to the private sector, result from this action.

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

Dated: July 24, 1997.

William Rice,

Acting Regional Administrator.

[FR Doc. 97-21696 Filed 8-14-97; 8:45 am]

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