SUBJECT: 

FROM: 

THRU: 

Technical Support Document for the Iowa State Implementation Plan (SIP) Revision for 

Permit Modifications, Muscatine Power and Water, and Union Tank Car Company, 

Muscatine, Iowa Heather Hamilton, Iowa State \1lt.£ 

Community Partnership Programs Section 

Air Planning and Development Branch 

Michael Jay, Section Chief 

Atmospheric Programs Section 

Air Planning and Development Branch 

Joshua Tapp, Branch Chief 

Air Planning and Development Branch 

TO: IA-167A; EPA-R07-0AR-2015-0159 

On December 1, 2014, EPA Region 7 took final action to approve a control strategy SIP for the State of 

Iowa's 2006 24-hour PM2.s National Ambient Air Quality Standard (NAAQS) for Muscatine, Iowa. The 

control strategy SIP included construction permits for Grain Processing Corporation, Muscatine Power 

and Water (MPW), and Union Tank Car Company (UTLX). 

On November 10, 2014, EPA received the state's request to approve changes to the MPW and UTLX 

PM2.s permits. The request was accompanied by a revised modeling analysis that demonstrated 

continued attainment as well as documentation from the notice to the public to comment and review on 

the drafts. 

This request, to modify MPW and UTLX permits, preceded the EPA's action approving the Muscatine 

PM2.s SIP. In an effort to expeditiously move forward with the final action for the state's request to 

approve the control strategy for the 2006 PM2.s in Muscatine, EPA Region 7 made the decision to 

finalize the control strategy SIP and develop a separate action for the construction permit modifications. 

The Iowa Department of Natural Resources (IDNR) notices to the public to comment and review the 

drafts were published in the Muscatine Journal on July 30, 2014, and August 1, 2014, for UTLX and 

MPW, respectively, with a comment period of 30 days. Tear sheets were submitted with the November 

10, 2014, request as proof of publication. In addition to hard copy subscriptions, the Muscatine Journal 

Printed on Recycled Paper 
emission point. 

MPW: MPW is a municipal electric generating station and the primary sources of PM2.s emissions are from 

three coal-fired boilers and the associated coal handling and storage equipment. The facility-wide 

actual PM2.s emissions for MPW are 58.3 tons per year. (NOTE- this is for a given year and fluctuates 

from year to year). The estimated emission reductions from the implementation of the control strategy 

is 1.2%. 

Due to testing difficulties (required sampling time was prohibitively long), IDNR increased the 

permitted limit for four emission units as illustrated in the following table. IDNR modeled the increase 

and the increase did not impact the PM2.s NAAQS. EPA Region 7 technical staff (modeling) concurred. 

EPA Region 7 Permitting Engineers noted that a project with an increase in emissions of this level is 

relatively insignificant and would not typically require a permit or a permit revision. Because these 

permits are part of the Muscatine PM2.s. SIP, the permit modifications were public noticed and the 

existing permits in the SIP will be replaced with the modified permits. 

MPW Original 

emission permit Revised permits 

unit limits PMz.s limits PMz.s Increase Notes 

EU20 EU21 .0006 lblhr .036lblhr .045 tons 

EU22 per year Increase includes all units 

EU23 .00121 lblhr . 036lblhr (tpy) collectively . 

UTLX: UTLX supplies and reconditions rail tank cars for use through rental agreements. The primary sources of 

PM2.s are removal of paint from rail tank cars, repair of rail tank cars and paint application through a 

spray system for the rail tank cars. UTLX is not considered a major source ofPM2.s but is located near 

the PM2.s monitor. 

Due to the results of a stack test, IDNR increased the permitted limit in the rubber lining area as 

illustrated in the following table. A project with an increase in emissions of this level is relatively 

insignificant and would not typically require a permit or a permit revision. Because these permits are 

part of the Muscatine PM2.s. SIP, the permit modifications were public noticed and the existing permits 

in the SIP will be replaced with the modified permits. 

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UTLX Original Revised 

emission permit permits 

unit limits PM2.s limits PM2.s Increase Notes 

Revision required since change 

could affect concentrations outside 

of fence line. Modeling indicated 

EU6 No change No change No change concentrations were not affected. 

EU7 .0062lblhr .0085lblhr .010 tpy Does not impact PM2.s NAAQS 

Revision required since change 

could affect concentrations outside 

of fence line. Modeling indicated 

EU8 No change No change No change concentrations were not affected. 

Revision required since change 

could affect concentrations outside 

of fence line. Modeling indicated 

EU9 No change No change No change concentrations were not affected. 

UTLX permits were also modified to include facility-wide compliance methodology requirements for 

National Emission Standards for Hazardous Air Pollutants (NESHAP) 40 CFR Part 63 Subpart MMMM 

(Miscellaneous Metal Parts and Products Surface Coating). Facilities are given multiple compliance 

options for this NESHAP and the permit is being revised to clarify the option that Union Tank Car 

Company has elected (facility-wide rather than individual EU limits). There is no PM2.s emission 

increase from this revision. 

For a detailed explanation of the modeling methodology and inventory development, please refer to 

page 30 of the IDNR control strategy SIP submittal (Docket: EPA-R07-0AR-2015-0159). 

SUMMARY: 

EPA is approving revisions with direct final action to the SIP for the State of Iowa to include modified 

permits for Muscatine County, Iowa. The SIP revision addresses modifications to construction permits 

that were included in the 2006 24-hour PM2.s NAAQS control strategy proposed in the Federal Register 

on August 11, 2014, and published as a final rule on December 1, 2014, with the effective date of 

December 31, 2014 (79 FR 71025). The state's submission of modified permits included a technical 

demonstration and a revised air dispersion modeling analysis that demonstrated continued attainment of 

the 2006 24-hour PM2.s NAAQS. 

This action will also make an administrative correction to a permit number. 

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