40086 Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 

Environmental Management (ADEM), 

on May 7, 2012. The portion of the 

revision that EPA is proposing to 

approve relates to the State’s Prevention 

of Significant Deterioration (PSD) 

permitting regulations. In particular, the 

revision adds a definition of 

‘‘replacement unit’’ and provides that a 

replacement unit is a type of existing 

emissions unit under the definition of 

‘‘emissions unit.’’ This action is being 

taken pursuant to the Clean Air Act 

(CAA or Act). 

DATES: Written comments must be 

received on or before September 25, 

2017. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R04– 

OAR–2017–0371 at http://

www.regulations.gov. Follow the online 

instructions for submitting comments. 

Once submitted, comments cannot be 

edited or removed from Regulations.gov. 

EPA may publish any comment received 

to its public docket. Do not submit 

electronically any information you 

consider to be Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Multimedia submissions (audio, video, 

etc.) must be accompanied by a written 

comment. The written comment is 

considered the official comment and 

should include discussion of all points 

you wish to make. EPA will generally 

not consider comments or comment 

contents located outside of the primary 

submission (i.e., on the web, cloud, or 

other file sharing system). For 

additional submission methods, the full 

EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www2.epa.gov/dockets/ 

commenting-epa-dockets. 

FOR FURTHER INFORMATION CONTACT: 

Andres Febres of the Air Regulatory 

Management Section, Air Planning and 

Implementation Branch, Air, Pesticides 

and Toxics Management Division, U.S. 

Environmental Protection Agency, 

Region 4, 61 Forsyth Street SW., 

Atlanta, Georgia 30303–8960. Mr. 

Febres can be reached via telephone at 

(404) 562–8966 or via electronic mail at 

febres-martinez.andres@epa.gov. 

SUPPLEMENTARY INFORMATION: 

In the Final Rules Section of this 

Federal Register, EPA is approving the 

portion of Alabama’s May 7, 2012, SIP 

revision addressing the State’s PSD 

program as a direct final rule without 

prior proposal because the Agency 

views this as a noncontroversial 

submittal and anticipates no adverse 

comments. A detailed rationale for the 

approval is set forth in the direct final 

rule and incorporated herein by 

reference. If no adverse comments are 

received in response to this rule, no 

further activity is contemplated. If EPA 

receives adverse comments, the direct 

final rule will be withdrawn and all 

adverse comments received will be 

addressed in a subsequent final rule 

based on this proposed rule. EPA will 

not institute a second comment period 

on this document. Any parties 

interested in commenting on this 

document should do so at this time. 

Dated: August 7, 2017. 

V. Anne Heard, 

Acting Regional Administrator, Region 4. 

[FR Doc. 2017–17343 Filed 8–23–17; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R07–OAR–2017–0416; FRL–9966–60– 

Region 7] 

Approval of Iowa’s Air Quality 

Implementation Plan; Muscatine Sulfur 

Dioxide Nonattainment Area 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to approve 

the State Implementation Plan (SIP) 

revision, which the State of Iowa (the 

state) submitted to the EPA on May 26, 

2016, for attaining the 1-hour sulfur 

dioxide (SO2) primary National Ambient 

Air Quality Standard (NAAQS) for the 

Muscatine nonattainment area. This 

plan (herein called a ‘‘nonattainment 

plan’’) includes the state’s attainment 

demonstration and other elements 

required under Clean Air Act (CAA) 

sections 172, 191, and 192. In addition 

to an attainment demonstration, the 

plan addresses the requirement for 

meeting reasonable further progress 

(RFP) toward attainment of the NAAQS, 

reasonably available control measures 

and reasonably available control 

technology (RACM/RACT), base-year 

and projection-year emission 

inventories, and contingency measures. 

The EPA proposes to conclude that the 

state has appropriately demonstrated 

that the plan provisions provide for 

attainment of the 2010 1-hour primary 

SO2 NAAQS in the Muscatine 

nonattainment area by the applicable 

attainment date and that the plan meets 

the other applicable requirements under 

CAA sections 172, 191, and 192. 

DATES: Comments must be received on 

or before September 25, 2017. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R07– 

OAR–2017–0416 to https://

www.regulations.gov. Follow the online 

instructions for submitting comments. 

Once submitted, comments cannot be 

edited or removed from Regulations.gov. 

The EPA may publish any comment 

received to its public docket. Do not 

submit electronically any information 

you consider to be Confidential 

Business Information (CBI) or other 

information whose disclosure is 

restricted by statute. Multimedia 

submissions (audio, video, etc.) must be 

accompanied by a written comment. 

The written comment is considered the 

official comment and should include 

discussion of all points you wish to 

make. The EPA will generally not 

consider comments or comment 

contents located outside of the primary 

submission (i.e., on the web, cloud, or 

other file sharing system). For 

additional submission methods, the full 

EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

https://www2.epa.gov/dockets/ 

commenting-epa-dockets. 

FOR FURTHER INFORMATION CONTACT: 

Tracey Casburn, Environmental 

Protection Agency, Air Planning and 

Development Branch, 11201 Renner 

Boulevard, Lenexa, Kansas 66219 at 

(913) 551–7016, or by email at 

casburn.tracey@epa.gov. 

SUPPLEMENTARY INFORMATION: 

Throughout this document whenever 

‘‘we,’’ ‘‘us,’’ and ‘‘our’’ is used, we mean 

the EPA. 

Organization of this document. The 

following outline is provided to aid in 

locating information in this preamble. 

Table of Contents 

I. Why was Iowa required to submit an SO2

plan for the Muscatine area? 

II. Requirements for SO2 Nonattainment Area 

Plans 

III. Attainment Demonstration and Longer 

Term Averaging 

IV. Review of Modeled Attainment Plan 

A. Model Selection 

B. Meteorological Data 

C. Emissions Data 

D. Emission Limits 

1. Enforceability 

2. Longer Term Averaging 

E. Background Concentrations 

F. Summary of Results 

1. Phase 1—Preliminary Analysis 

2. Phase 2—Control Strategy Development 

V. Review of Other Plan Requirements 

A. Emissions Inventory and the 

Quantification of Emissions 

B. RACM/RACT 

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C. Nonattainment New Source Review 

(NNSR) 

D. Reasonable Further Progress (RFP) 

E. Contingency Measures 

VI. Additional Elements of the State’s 

Submittal 

A. Compliance With Section 110(a)(2) of 

the CAA 

B. Equivalent Techniques 

VII. EPA’s Proposed Action 

VIII. Incorporation by Reference 

IX. Statutory and Executive Order Reviews 

I. Why was Iowa required to submit an 

SO2 plan for the Muscatine area? 

On June 22, 2010, the EPA 

promulgated a new 1-hour primary SO2

NAAQS of 75 parts per billion (ppb), 

which is met at an ambient air quality 

monitoring site when the 3-year average 

of the annual 99th percentile of 1-hour 

daily maximum concentrations does not 

exceed 75 ppb, as determined in 

accordance with appendix T of 40 CFR 

part 50. See 75 FR 35520, codified at 40 

CFR 50.17(a)–(b). On August 5, 2013, 

the EPA designated 29 areas of the 

country as nonattainment for the 2010 

SO2 NAAQS, including the Muscatine 

area in the State of Iowa. See 78 FR 

47191, codified at 40 CFR part 81, 

subpart C. These area designations were 

effective October 4, 2013. Section 191 of 

the CAA directs states to submit SIPs for 

areas designated as nonattainment for 

the SO2 NAAQS to the EPA within 18 

months of the effective date of the 

designation, i.e., by no later than April 

4, 2015. These SIPs must demonstrate 

that the respective areas will attain the 

NAAQS as expeditiously as practicable, 

but no later than 5 years from the 

effective date of designation, which is 

October 4, 2018. 

On March 18, 2016, the EPA 

published an action that the State of 

Iowa failed to submit the required SO2

nonattainment plan for the Muscatine 

area by the SIP submittal deadline. See 

81 FR 14736. This finding initiated a 

deadline under CAA section 179(a) for 

the potential imposition of new source 

and highway funding sanctions. 

However, pursuant to Iowa’s submittal 

of May 26, 2016, and the SIP becoming 

complete by operation of law on 

November 26, 2016, the sanctions under 

section 179(a) will not be imposed. 

Additionally, under CAA section 110(c), 

the finding triggers a requirement that 

the EPA promulgate a Federal 

Implementation Plan (FIP) within two 

years of the finding unless, by that time 

(a) the state has made the necessary 

complete submittal and (b) EPA has 

approved the submittal as meeting 

applicable requirements. This FIP 

obligation will not apply if EPA makes 

final the approval action proposed here 

by March 18, 2018. 

The remainder of this preamble 

describes the requirements that 

nonattainment SIPs must meet in order 

to obtain EPA approval, provides a 

review of the state’s plan with respect 

to these requirements, and describes the 

EPA’s proposed action on the plan. 

II. Requirements for SO2

Nonattainment Area Plans 

Nonattainment SIPs must meet the 

applicable requirements of the CAA, 

and specifically CAA sections 172, 191 

and 192. The EPA’s regulations 

governing nonattainment SIPs are set 

forth at 40 CFR part 51, with specific 

procedural requirements and control 

strategy requirements residing at 

subparts F and G, respectively. Soon 

after Congress enacted the 1990 

Amendments to the CAA, EPA issued 

comprehensive guidance on SIPs, in a 

document entitled the ‘‘General 

Preamble for the Implementation of 

Title I of the Clean Air Act Amendments 

of 1990,’’ published at 57 FR 13498 

(April 16, 1992) (General Preamble). 

Among other things, the General 

Preamble addressed SO2 SIPs and 

fundamental principles for SIP control 

strategies. Id., at 13545–49, 13567–68. 

On April 23, 2014, the EPA issued 

recommended guidance for meeting the 

statutory requirements in SO2 SIPs, in a 

document entitled, ‘‘Guidance for 1- 

Hour SO2 Nonattainment Area SIP 

Submissions,’’ (April 2014 guidance) 

available at https://www.epa.gov/sites/ 

production/files/2016-06/documents/ 

20140423guidance_nonattainment_

sip.pdf. In this guidance the EPA 

described the statutory requirements for 

a complete nonattainment area SIP, 

which includes: An accurate emissions 

inventory of current emissions for all 

sources of SO2 within the 

nonattainment area; an attainment 

demonstration; demonstration of RFP; 

implementation of RACM (including 

RACT); new source review (NSR) and, 

adequate contingency measures for the 

affected area. 

In order for the EPA to fully approve 

a SIP as meeting the requirements of 

CAA sections 110, 172 and 191–192 and 

EPA’s regulations at 40 CFR part 51, the 

SIP for the affected area needs to 

demonstrate to EPA’s satisfaction that 

each of the aforementioned 

requirements have been met. Under 

CAA sections 110(l) and 193, the EPA 

may not approve a SIP that would 

interfere with any applicable 

requirement concerning NAAQS 

attainment and RFP, or any other 

applicable requirement, and no 

requirement in effect (or required to be 

adopted by an order, settlement, 

agreement, or plan in effect before 

November 15, 1990) in any area which 

is a nonattainment area for any air 

pollutant, may be modified in any 

manner unless it insures equivalent or 

greater emission reductions of such air 

pollutant. 

III. Attainment Demonstration and 

Longer Term Averaging 

CAA section 172(c)(1) directs states 

with areas designated as nonattainment 

to demonstrate that the submitted plan 

provides for attainment of the NAAQS. 

40 CFR part 51, subpart G further 

delineates the control strategy 

requirements that SIPs must meet, and 

EPA has long required that all SIPs and 

control strategies reflect four 

fundamental principles of 

quantification, enforceability, 

replicability, and accountability. 

General Preamble, at 13567–68. SO2

attainment plans must consist of two 

components: (1) Emission limits and 

other control measures that assure 

implementation of permanent, 

enforceable and necessary emission 

controls, and (2) a modeling analysis 

which meets the requirements of 40 CFR 

part 51, appendix W which 

demonstrates that these emission limits 

and control measures provide for timely 

attainment of the primary SO2 NAAQS 

as expeditiously as practicable, but by 

no later than the attainment date for the 

affected area. In all cases, the emission 

limits and control measures must be 

accompanied by appropriate methods 

and conditions to determine compliance 

with the respective emission limits and 

control measures and must be 

quantifiable (i.e., a specific amount of 

emission reduction can be ascribed to 

the measures), fully enforceable 

(specifying clear, unambiguous and 

measureable requirements for which 

compliance can be practicably 

determined), replicable (the procedures 

for determining compliance are 

sufficiently specific and non-subjective 

so that two independent entities 

applying the procedures would obtain 

the same result), and accountable 

(source specific limits must be 

permanent and must reflect the 

assumptions used in the SIP 

demonstrations). 

The EPA’s April 2014 guidance 

recommends that the emission limits be 

expressed as short-term average limits 

(e.g., addressing emissions averaged 

over one or three hours), but also 

describes the option to utilize emission 

limits with longer averaging times of up 

to 30 days so long as the state meets 

various suggested criteria. See 2014 

guidance, pp. 22 to 39. The guidance 

recommends that—should states and 

sources utilize longer averaging times— 

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40088 Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 

1An ‘‘average year’’ is used to mean a year with 

average air quality. While 40 CFR 50 appendix T 

provides for averaging three years of 99th percentile 

daily maximum values (e.g., the fourth highest 

maximum daily concentration in a year with 365 

days with valid data), this discussion and an 

example below uses a single ‘‘average year’’ in order 

to simplify the illustration of relevant principles. 

the longer term average limit should be 

set at an adjusted level that reflects a 

stringency comparable to the 1-hour 

average limit at the critical emission 

value shown to provide for attainment 

that the plan otherwise would have set. 

The April 2014 guidance provides an 

extensive discussion of the EPA’s 

rationale for concluding that 

appropriately set comparably stringent 

limitations based on averaging times as 

long as 30 days can be found to provide 

for attainment of the 2010 SO2 NAAQS. 

In evaluating this option, the EPA 

considered the nature of the standard, 

conducted detailed analyses of the 

impact of use of 30-day average limits 

on the prospects for attaining the 

standard, and carefully reviewed how 

best to achieve an appropriate balance 

among the various factors that warrant 

consideration in judging whether a 

state’s plan provides for attainment. Id. 

at pp. 22 to 39. See also id. at 

Appendices B, C, and D. 

As specified in 40 CFR 50.17(b), the 

1-hour primary SO2 NAAQS is met at an 

ambient air quality monitoring site 

when the 3-year average of the annual 

99th percentile of daily maximum 1- 

hour concentrations is less than or equal 

to 75 parts per billion. In a year with 

365 days of valid monitoring data, the 

99th percentile would be the fourth 

highest daily maximum 1-hour value. 

The 2010 SO2 NAAQS, including this 

form of determining compliance with 

the standard, was upheld by the U.S. 

Court of Appeals for the District of 

Columbia Circuit in Nat’l Envt’l Dev. 

Ass’n’s Clean Air Project v. EPA, 686 

F.3d 803 (D.C. Cir. 2012). Because the 

standard has this form, a single 

exceedance does not create a violation 

of the standard. Instead, at issue is 

whether a source operating in 

compliance with a properly set longer 

term average could cause exceedances, 

and if so the resulting frequency and 

magnitude of such exceedances, and in 

particular whether the EPA can have 

reasonable confidence that a properly 

set longer term average limit will 

provide that the average fourth highest 

daily maximum value will be at or 

below 75 ppb. A synopsis of how EPA 

judges whether such plans ‘‘provide for 

attainment,’’ based on modeling of 

projected allowable emissions and in 

light of the NAAQS’ form for 

determining attainment at monitoring 

sites, follows. 

For plans for SO2 based on 1-hour 

emission limits, the standard approach 

is to conduct modeling using fixed 

emission rates. The maximum emission 

rate that would be modeled to result in 

attainment (i.e., in an ‘‘average year’’ 1

shows three, not four days with 

maximum hourly levels exceeding 75 

ppb) is labeled the ‘‘critical emission 

value.’’ The modeling process for 

identifying this critical emissions value 

inherently considers the numerous 

variables that affect ambient 

concentrations of SO2, such as 

meteorological data, background 

concentrations, and topography. In the 

standard approach, the state would then 

provide for attainment by setting a 

continuously applicable 1-hour 

emission limit at this critical emission 

value. 

The EPA recognizes that some sources 

have highly variable emissions, for 

example due to variations in fuel sulfur 

content and operating rate, that can 

make it extremely difficult, even with a 

well-designed control strategy, to ensure 

in practice that emissions for any given 

hour do not exceed the critical emission 

value. The EPA also acknowledges the 

concern that longer term emission limits 

can allow short periods with emissions 

above the ‘‘critical emissions value,’’ 

which, if coincident with 

meteorological conditions conducive to 

high SO2 concentrations, could in turn 

create the possibility of a NAAQS 

exceedance occurring on a day when an 

exceedance would not have occurred if 

emissions were continuously controlled 

at the level corresponding to the critical 

emission value. However, for several 

reasons, the EPA believes that the 

approach recommended in its April 

2014 guidance document suitably 

addresses this concern. First, from a 

practical perspective, the EPA expects 

the actual emission profile of a source 

subject to an appropriately set longer 

term average limit to be similar to the 

emission profile of a source subject to 

an analogous 1-hour average limit. The 

EPA expects this similarity because it 

has recommended that the longer term 

average limit be set at a level that is 

comparably stringent to the otherwise 

applicable 1-hour limit (reflecting a 

downward adjustment from the critical 

emissions value) and that takes the 

source’s emissions profile into account. 

As a result, the EPA expects either form 

of emission limit to yield comparable air 

quality. 

Second, from a more theoretical 

perspective, the EPA has compared the 

likely air quality with a source having 

maximum allowable emissions under an 

appropriately set longer term limit, as 

compared to the likely air quality with 

the source having maximum allowable 

emissions under the comparable 1-hour 

limit. In this comparison, in the 1-hour 

average limit scenario, the source is 

presumed at all times to emit at the 

critical emission level, and in the longer 

term average limit scenario, the source 

is presumed occasionally to emit more 

than the critical emission value but on 

average, and presumably at most times, 

to emit well below the critical emission 

value. In an ‘‘average year,’’ compliance 

with the 1-hour limit is expected to 

result in three exceedance days (i.e., 

three days with hourly values above 75 

ppb) and a fourth day with a maximum 

hourly value at 75 ppb. By comparison, 

with the source complying with a longer 

term limit, it is possible that additional 

exceedances would occur that would 

not occur in the 1-hour limit scenario (if 

emissions exceed the critical emission 

value at times when meteorology is 

conducive to poor air quality). However, 

this comparison must also factor in the 

likelihood that exceedances that would 

be expected in the 1-hour limit scenario 

would not occur in the longer term limit 

scenario. This result arises because the 

longer term limit requires lower 

emissions most of the time (because the 

limit is set well below the critical 

emission value), so a source complying 

with an appropriately set longer term 

limit is likely to have lower emissions 

at critical times than would be the case 

if the source were emitting as allowed 

with a 1-hour limit. 

As a hypothetical example to 

illustrate these points, suppose a source 

that always emits 1000 pounds of SO2

per hour, which results in air quality at 

the level of the NAAQS (i.e., results in 

a design value of 75 ppb). Suppose 

further that in an ‘‘average year,’’ these 

emissions cause the 5 highest maximum 

daily average 1-hour concentrations to 

be 100 ppb, 90 ppb, 80 ppb, 75 ppb, and 

70 ppb. Then suppose that the source 

becomes subject to a 30-day average 

emission limit of 700 pounds per hour. 

It is theoretically possible for a source 

meeting this limit to have emissions that 

occasionally exceed 1000 pounds per 

hour, but with a typical emissions 

profile emissions would much more 

commonly be between 600 and 800 

pounds per hour. In this simplified 

example, assume a zero background 

concentration, which allows one to 

assume a linear relationship between 

emissions and air quality. (A nonzero 

background concentration would make 

the mathematics more difficult but 

would give similar results.) Air quality 

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2For example, if the critical emission value is 

1000 pounds of SO2 per hour, and a suitable 

adjustment factor is determined to be 70 percent, 

the recommended longer term average limit would 

be 700 pounds per hour. 

will depend on what emissions happen 

on what critical hours, but suppose that 

emissions at the relevant times on these 

5 days are 800 pounds/hour, 1100 

pounds per hour, 500 pounds per hour, 

900 pounds per hour, and 1200 pounds 

per hour, respectively. (This is a 

conservative example because the 

average of these emissions, 900 pounds 

per hour, is well over the 30-day average 

emission limit.) These emissions would 

result in daily maximum 1-hour 

concentrations of 80 ppb, 99 ppb, 40 

ppb, 67.5 ppb, and 84 ppb. In this 

example, the fifth day would have an 

exceedance that would not otherwise 

have occurred, but the third and fourth 

days would not have exceedances that 

otherwise would have occurred. In this 

example, the fourth highest maximum 

daily concentration under the 30-day 

average would be 67.5 ppb. 

This simplified example illustrates 

the findings of a more complicated 

statistical analysis that EPA conducted 

using a range of scenarios using actual 

plant data. As described in appendix B 

of EPA’s April 2014 SO2 nonattainment 

planning guidance, the EPA found that 

the requirement for lower average 

emissions is highly likely to yield better 

air quality than is required with a 

comparably stringent 1-hour limit. 

Based on analyses described in 

appendix B of its April 2014 guidance, 

the EPA expects that an emission profile 

with maximum allowable emissions 

under an appropriately set comparably 

stringent 30-day average limit is likely 

to have the net effect of having a lower 

number of exceedances and better air 

quality than an emission profile with 

maximum allowable emissions under a 

1-hour emission limit at the critical 

emission value. This result provides a 

compelling policy rationale for allowing 

the use of a longer averaging period, in 

appropriate circumstances where the 

facts indicate this result can be expected 

to occur. 

The question then becomes whether 

this approach—which is likely to 

produce a lower number of overall 

exceedances even though it may 

produce some unexpected exceedances 

above the critical emission value— 

meets the requirement in section 

110(a)(1) and 172(c)(1) for state 

implementation plans to ‘‘provide for 

attainment’’ of the NAAQS. For SO2, as 

for other pollutants, it is generally 

impossible to design a nonattainment 

plan in the present that will guarantee 

that attainment will occur in the future. 

A variety of factors can cause a welldesigned attainment plan to fail and 

unexpectedly not result in attainment, 

for example if meteorology occurs that 

is more conducive to poor air quality 

than was anticipated in the plan. 

Therefore, in determining whether a 

plan meets the requirement to provide 

for attainment, the EPA’s task is 

commonly to judge not whether the 

plan provides absolute certainty that 

attainment will in fact occur, but rather 

whether the plan provides an adequate 

level of confidence of prospective 

NAAQS attainment. From this 

perspective, in evaluating use of a 30- 

day average limit, EPA must weigh the 

likely net effect on air quality. Such an 

evaluation must consider the risk that 

occasions with meteorology conducive 

to high concentrations will have 

elevated emissions leading to 

exceedances that would not otherwise 

have occurred, and must also weigh the 

likelihood that the requirement for 

lower emissions on average will result 

in days not having exceedances that 

would have been expected with 

emissions at the critical emissions 

value. Additional policy considerations, 

such as in this case the desirability of 

accommodating real world emissions 

variability without significant risk of 

violations, are also appropriate factors 

for the EPA to weigh in judging whether 

a plan provides a reasonable degree of 

confidence that the plan will lead to 

attainment. Based on these 

considerations, especially given the 

high likelihood that a continuously 

enforceable limit averaged over as long 

as 30 days, determined in accordance 

with the EPA’s April 2014 guidance, 

will result in attainment, the EPA 

believes as a general matter that such 

limits, if appropriately determined, can 

reasonably be considered to provide for 

attainment of the 2010 SO2 NAAQS. 

The April 2014 guidance offers 

specific recommendations for 

determining an appropriate longer term 

average limit. The recommended 

method starts with determination of the 

1-hour emission limit that would 

provide for attainment (i.e., the critical 

emission value), and applies an 

adjustment factor to determine the 

(lower) level of the longer term average 

emission limit that would be estimated 

to have a stringency comparable to the 

otherwise necessary 1-hour emission 

limit. This method uses a database of 

continuous emission data reflecting the 

type of control that the source will be 

using to comply with the SIP emission 

limits, which (if compliance requires 

new controls) may require use of an 

emission database from another source. 

The recommended method involves 

using these data to compute a complete 

set of emission averages, computed 

according to the averaging time and 

averaging procedures of the prospective 

emission limitation. In this 

recommended method, the ratio of the 

99th percentile among these long term 

averages to the 99th percentile of the 1- 

hour values represents an adjustment 

factor that may be multiplied by the 

candidate 1-hour emission limit to 

determine a longer term average 

emission limit that may be considered 

comparably stringent.2 The April 2014 

guidance also addresses a variety of 

related topics, such as the potential 

utility of setting supplemental emission 

limits, such as mass-based limits, to 

reduce the likelihood and/or magnitude 

of elevated emission levels that might 

occur under the longer term emission 

rate limit. 

Preferred air quality models for use in 

regulatory applications are described in 

appendix A of the EPA’s Guideline on 

Air Quality Models (40 CFR part 51, 

appendix W (appendix W)). In 2005, the 

EPA promulgated the American 

Meteorological Society/Environmental 

Protection Agency Regulatory Model 

(AERMOD) as the Agency’s preferred 

near-field dispersion modeling for a 

wide range of regulatory applications 

addressing stationary sources (for 

example in estimating SO2

concentrations) in all types of terrain 

based on extensive developmental and 

performance evaluation. Supplemental 

guidance on modeling for purposes of 

demonstrating attainment of the SO2

standard is provided in appendix A to 

the April 2014 guidance. Appendix A 

provides extensive guidance on the 

modeling domain, the source inputs, 

assorted types of meteorological data, 

and background concentrations. 

Consistency with the recommendations 

in this guidance is generally necessary 

for the attainment demonstration to 

offer adequately reliable assurance that 

the plan provides for attainment. 

As stated previously, attainment 

demonstrations for the 2010 1-hour 

primary SO2 NAAQS must demonstrate 

future attainment and maintenance of 

the NAAQS in the entire area 

designated as nonattainment (i.e., not 

just at the violating monitor) by using 

air quality dispersion modeling (see 

appendix W to 40 CFR part 51) to show 

that the mix of sources and enforceable 

control measures and emission rates in 

an identified area will not lead to a 

violation of the SO2 NAAQS. For a 

short-term (i.e., 1-hour) standard, the 

EPA believes that dispersion modeling, 

using allowable emissions and 

addressing stationary sources in the 

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40090 Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 

3SO2 NAAQS Designations Modeling Technical 

Assistance Document, December 2013. 

4The Musser Park monitor was the violating 

monitor utilized during the designations process. 

5The state utilized the December 2013 version of 

the modeling TAD when completing its technical 

analysis. The modeling TAD has been revised since 

then; the TAD was revised in February 2016 and 

then again in August 2016. 

6A detailed analysis to support the use of the 

Davenport meteorological data from the Davenport 

airport was previously approved by EPA for use in 

the PM2.5 Muscatine SIP analysis. See 79 FR 46742. 

EPA finds use of the Davenport airport site 

meteorological data to be appropriate for the 2010 

1-hr SO2 Muscatine SIP. 

7https://www.epa.gov/sulfur-dioxidedesignations/so2-designations-round-1-iowa-staterecommendation-and-epa-response and provided in 

the docket of this rulemaking. 

affected area (and in some cases those 

sources located outside the 

nonattainment area which may affect 

attainment in the area) is technically 

appropriate, efficient and effective in 

demonstrating attainment in 

nonattainment areas because it takes 

into consideration combinations of 

meteorological and emission source 

operating conditions that may 

contribute to peak ground-level 

concentrations of SO2.

The meteorological data used in the 

analysis should generally be processed 

with the most recent version of 

AERMET. Estimated concentrations 

should include ambient background 

concentrations, should follow the form 

of the standard, and should be 

calculated as described in section 

2.6.1.2 of the August 23, 2010 

clarification memo ‘‘Applicability of 

Appendix W Modeling Guidance for the 

1-hr SO2 National Ambient Air Quality 

Standard’’ (U. S. EPA, 2010a) (August 

2010 1-hour SO2 clarification memo). 

IV. Review of Modeled Attainment Plan 

The following discussion evaluates 

various features of the modeling that 

Iowa used in its attainment 

demonstration. 

A. Model Selection 

Iowa’s attainment demonstration used 

the most current version of AERMOD 

available during each phase of its 

analysis (i.e., the determining sources 

culpable to nonattainment phase and 

the control strategy phase). As 

previously stated, AERMOD is the 

preferred model for this application. 

The final control strategy modeling 

analysis utilized version 15181. The 

state asserts that all analyses were 

conducted with EPA’s regulatory default 

options and considering EPA’s guidance 

documents including the August 2010 

1-hour SO2 clarification memo; the 

‘‘Additional Clarification Regarding 

Application of Appendix W Modeling 

Guidance for the 1-hour NO2 National 

Ambient Air Quality Standard’’ memo 

(March 2011 1-hour NO2 clarification 

memo); and the December 2013 SO2

Modeling Technical Assistance 

Document (TAD).3 The receptor grid 

was centered on the Musser Park 

monitor, and extended out to the edges 

of the nonattainment area.4 Those 

portions of the fence lines of the 

facilities being evaluated that fell 

outside of the nonattainment area were 

omitted from the analysis. Finer grid 

spacing of 50 meters was used to resolve 

modeled impacts around other nearby 

individual facilities included in the 

analyses, but finer grid spacing was 

applied only around sources within the 

confines of the nonattainment area. 

Receptors were excluded from areas 

within the property boundaries of each 

facility in the analysis. The most recent 

version of AERMAP (11103) was used to 

import terrain and source elevations 

from the National Elevation Dataset 

(NED). All building downwash analyses 

were conducted using the most recent 

version (04274) of EPA’s Building 

Profile Input Program with Plume Rise 

Enhancements (BPIP-Prime). EPA finds 

the selection and use of these inputs to 

AERMOD, AERMAP and BPIP-Prime to 

be appropriate and in accordance with 

appendix W and applicable EPA 

guidance, such as the TAD.5

B. Meteorological Data 

Modeling for the Muscatine 1-hr SO2

nonattainment SIP was conducted using 

the surface station and upper air data 

from the Davenport airport, and used 

consecutive years from 2008–2012.6

This represents the most recent, readily 

available 5-year period at the time of the 

initial analysis per section 8.3.1.2 of 40 

CFR part 51 appendix W. The most 

current version of AERMET available 

during each phase of the analysis was 

used. The final control strategy analysis 

utilized data processed with AERMET 

version 14134. The state utilized 

AERMINUTE to process 1-minute ASOS 

wind data to generate hourly average 

winds for input to AERMET. EPA finds 

the selection and use of these inputs to 

AERMET to be appropriate and in 

accordance with appendix W and 

applicable EPA guidance, such as the 

TAD. 

C. Emissions Data 

The state utilized information from 

the technical support document (TSD) it 

submitted to EPA during the 

nonattainment boundary 

recommendations to inform which 

sources needed to be included in its 

nonattainment SIP modeling.7 The 

nonattainment boundary analysis 

demonstrated that industrial sources 

along the Mississippi River have a role 

in causing or contributing to monitored 

exceedances at the Musser Park 

monitor. Based on this analysis, all 

major sources of SO2 emissions within 

the nonattainment area- Grain 

Processing Corporation (GPC), 

Muscatine Power and Water (MPW), 

and Monsanto- were included in the 

nonattainment SIP control strategy 

analysis. 

As described in the state’s 

nonattainment SIP, GPC is the largest 

source of SO2 within the nonattainment 

area. GPC is a corn wet milling facility 

that processes grain into industrial, 

beverage, and fuel-grade ethanol, as well 

as a variety of grain based food 

products, industrial products, and 

animal feeds. Early in the corn wet 

milling process the grain is soaked 

(steeped) in large tanks where sulfur 

containing compounds are added to the 

steep water to reduce bacterial growth 

and help break down the kernels. The 

sulfur content in the steep water is 

generally low but does lead to SO2

emissions from a variety of downstream 

processes. The state asserts that 96 

percent of the SO2 emissions at GPC is 

generated by six coal-fired boilers. 

MPW is a municipal electric 

generating station. MPW produces 

steam through the combustion of fossil 

fuels, generally coal, and uses the steam 

to produce electricity. The largest 

sources of SO2 operated at MPW are 

three coal-fired boilers, Units 7, 8, and 

9, serving generators with nameplate 

capacities of 25, 937, and 175.5 

megawatts (MW), respectively. An 

auxiliary boiler operated at MPW is not 

capable of burning coal but has the 

potential to emit SO2 when firing on 

distillate fuel oil. 

Monsanto is a manufacturer and 

formulator of herbicides for agricultural 

use and also produces intermediates for 

herbicide manufacturing and 

formulation. A coal-fired boiler (Boiler 

#8) used for the production of on-site 

heat and power is the largest SO2 source 

at Monsanto. 

The state excluded four facilities 

located within the nonattainment area 

from the its nonattainment SIP 

modeling analysis: HNI Corporation— 

North Campus (HNI North); H.J. Heinz, 

L.P. (H.J. Heinz); Union Tank Car Co. 

(Union Tank); and HNI Corporation— 

Central Campus (HNI Central). As 

shown in the state’s nonattainment SIP, 

the cumulative actual emissions from 

these sources is relatively low; the 

sources emitted a combined 0.14 tons of 

SO2 per year (tpy) in 2011. See section 

V.A. Emissions Inventory in this 

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8According to information provided by the state 

in its nonattainment SIP, the Davenport monitor is 

located in Scott County, approximately 11 km from 

Linwood and Lafarge, and likely accounts for the 

emissions from Lafarge and Linwood. 

preamble for the 2011 emissions data 

from these sources. Additionally, if the 

state were to consider the maximum 

fuel capacity of a source like Heinz that 

has two boilers that burn natural gas, it 

is unlikely that the SO2 emissions 

would be sufficient enough to cause a 

significant concentration gradient. The 

TAD indicates that ‘‘other’’ sources in 

the area not causing significant 

concentration gradients in the vicinity 

of the source(s) of interest, should be 

included in the modeling via monitored 

background concentrations. The EPA 

agrees with the state’s recommendation 

that these facilities do not need to be 

explicitly modeled and that they are 

adequately characterized in the 

background SO2 concentrations. See 

section IV.E. Background 

Concentrations in this preamble for 

more detailed information regarding the 

determination of the background 

concentration. 

The state also evaluated several major 

sources of SO2 emissions located 

outside of the nonattainment area 

boundary- MidAmerican Energy Louisa 

Generating Station (LGS), Gerdau 

Ameristeel (Gerdau), SSAB and 

Linwood and Lafarge. Linwood and 

Lafarge, located in Scott County, are 

approximately 20 km away from the 

nonattainment area. The selection of the 

Davenport monitor to represent 

background likely accounts for the 

emissions from Linwood and Lafarge.8

As such, Linwood and Lafarge were 

excluded from further consideration. 

See section IV.E. Background 

Concentrations in this preamble for 

additional information. 

All included emission units were 

modeled using their actual stack 

parameters and site layout. There were 

no stacks above formula GEP (good 

engineering practice) height. There were 

stacks greater than 65 meters at GPC, 

MPW, and LGS and each of those stacks 

were adjacent to tall buildings making 

the formula height taller than the actual 

stack height. Therefore, each of those 

stacks were modeled at their actual 

stack heights. 

Per EPA’s April 2014 guidance, the 

use of allowable emissions and the 

modeling of intermittent emissions (for 

sources such as emergency generators 

and startup/shutdown emissions), for 

the purpose of modeling for SO2

attainment demonstrations, should 

follow the recommendations in EPA’s 

March 2011 1-hour NO2 clarification 

memo (even though it was specific to 

NO2). The state’s nonattainment SIP 

indicates that it addressed modeling 

intermittent sources in according with 

EPA’s March 2011 1-hour NO2

clarification memo, and as such all 

emission units that operate 

intermittently (e.g., emergency engines 

and fire pumps) were excluded from the 

analysis. Additionally, emission units 

that were limited to burning a specific 

fuel occasionally were modeled at 

emission rates that represent the fuel 

that is burned during normal operations. 

For example, the two auxiliary boilers 

(EP2 and EP3) operated by LGS are 

limited to burning fuel oil for no more 

than 48 hours per year. EP2 and EP3 

burn natural gas during normal 

operations therefore, EP2 and EP3 were 

modeled at emission rates associated 

with burning natural gas. EPA agrees 

with the state that it is appropriate to 

exclude these intermittent emissions 

(e.g., emergency engines and fire 

pumps) in the analysis and modeling 

the fuel burned during normal 

operations, as it is consistent with 

appendix W and the TAD. 

The state’s nonattainment SIP 

acknowledges that, although SO2

emissions in and near the 

nonattainment area are principally 

attributable to point sources, a 

comprehensive emissions inventory 

should include an assessment of the 

other source sectors. The state asserted 

that it accomplished this by using 

estimates of air emissions for the 

onroad, nonroad, and nonpoint (area) 

sources from EPA’s 2011 National 

Emissions Inventory (NEI) datasets. 

According to the state’s sector summary 

analyses using EPA’s SCC (source 

classification code) full detail data files 

from the 2011 NEI (version 2, dated 

March 4, 2015), approximately 2.64 tons 

of SO2 were emitted by onroad mobile 

sources in all of Muscatine County (this 

includes areas within and outside of the 

nonattainment area). Nonroad mobile 

sources (which include non-road 

equipment, locomotives, commercial 

marine vessels, and aircraft) contributed 

approximately 1.99 tpy of SO2. Again, 

that estimate includes nonroad mobile 

sources across all of Muscatine County. 

The state asserts that nonpoint (area) 

SO2 emissions were also relatively low, 

at approximately 18.73 tpy. Of that total, 

roughly half (8.92 tons) was associated 

with emissions mostly from prescribed 

fires. As with the mobile sectors, the 

nonpoint totals also represent sums 

across all of Muscatine County. The 

EPA agrees with the state’s proposal that 

onroad, nonroad, and nonpoint sources 

in and near the Muscatine 

nonattainment area are adequately 

represented by background 

concentrations included in modeling 

analysis and that further consideration 

of these sectors is unnecessary. See 

section IV.E. Background 

Concentrations and section V. A. 

Emissions Inventory in this preamble 

for more detailed information. 

D. Emission Limits 

Section 172(c)(6) of the CAA requires 

that the state’s nonattainment plan 

include enforceable emission 

limitations, and such other control 

measures, means or techniques 

(including economic incentives such as 

fees, marketable permits, and auctions 

of emission rights), as well as schedules 

and timetables for compliance, as may 

be necessary or appropriate to provide 

for attainment of such standard in such 

area by the applicable attainment date. 

See General Preamble at 13567–68. 

Part of the review of state’s attainment 

plan must address the use of these 

limits, both with respect to the general 

suitability of using such limits for the 

purpose of meeting the requirements of 

CAA § 172(c)(6) with respect to whether 

the particular limits included in the 

plan have been suitably demonstrated to 

provide for attainment. The first 

subsection that follows addresses the 

enforceability of the limits in the plan, 

and the second subsection that follows 

addresses in the limits in particular the 

longer term average limits (i.e., the 21- 

day average limit for MPW). 

1. Enforceability 

As specified in section 172(c)(6) and 

section 110(a)(2)(A) of the CAA and 75 

FR 35520, emission limitations, control 

measures and other elements in the SIP 

must be enforceable by the state and 

EPA. Working with GPC, MPW, and 

Monsanto the state developed an 

implementable control strategy designed 

to ensure expeditious attainment of the 

1-hr SO2 NAAQS. The control strategy 

establishes source-specific control 

measures that include more stringent 

SO2 emissions limits, new control 

devices, and process changes. The 

state’s nonattainment SIP includes these 

control measures with specific 

timetables for implementation, 

establishes minimum performance 

criteria, and provides schedules for 

completing verification processes. See 

section V. B. RACM/RACT in this 

preamble for additional information. 

New air construction permits issued to 

GPC, MPW, and Monsanto include 

emissions limits, timetables for 

compliance, and enforcement criteria 

and are the enforceable documents 

included in the state’s nonattainment 

SIP that EPA is proposing to approve. 

As noted in the nonattainment SIP, the 

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9The MPW permit included as appendix C to the 

nonattainment SIP specifies that compliance with 

the emission standard of 1153 lb/hr of SO2 shall be 

demonstrated through the use a Continuous 

Emissions Monitoring System (CEMS) and shall be 

determined on a 21-day rolling average bases. The 

limit includes startup, shutdown and malfunction 

emissions. Compliance with the emission limit 

shall be demonstrated using the formula found in 

Permit Condition 15.8. The emission limit became 

effective January 1, 2017. 

state has the authority to implement 

each of the permits. Each permit 

includes notification, reporting, and 

recordkeeping requirements. The 

facilities must, for example, notify the 

state when they initiate and when they 

complete construction. Each permit also 

contains performance testing (emissions 

testing) obligations with specific 

schedules, methods, and frequencies for 

compliance. Each performance test must 

be approved by the state and a testing 

protocol must be submitted to the state 

in advance of the compliance 

demonstration. Results of the tests must 

be submitted in writing to the state in 

the form of a comprehensive report 

within six weeks of the completion of 

any testing. Additionally, GPC, MPW, 

and Monsanto are major sources under 

the Title V operating permit program 

and must submit semi-annual 

monitoring reports by September 30 and 

March 31, and an annual compliance 

certification by March 31, of each year. 

The state also inspects Title V sources 

at a minimum of every two years. In 

summary, the state has a comprehensive 

program to identify sources of violations 

and to undertake follow-up for 

compliance and enforcement. 

As noted in the state’s May 26, 2016, 

submittal letter, Iowa was included in 

the agency’s Response to Petition for 

Rulemaking; Restatement and Update of 

EPA’s SSM Policy Applicable to SIPs; 

Findings of Substantial Inadequacy; and 

SIP Calls To Amend Provisions 

Applying to Excess Emissions During 

Periods of Startup, Shutdown and 

Malfunction (SSM SIP call) published 

June 12, 2015, (80 FR 33839). In the 

SSM SIP call, subrule 567—Iowa 

Administrate Code (IAC) 24.1(1) was 

found to be ‘‘substantially inadequate’’ 

because it provides that excess 

emissions during periods of startup and 

shutdown are not a violation of an 

emission standard if good practices for 

minimizing emissions are followed. 

Each construction permit the state 

requested be included in the SIP apart 

if its control strategy contains SSM 

language from the subrule that is subject 

to the SIP call (Condition 6 of each 

permit). As such the state is requested 

that EPA not act on permit Condition 6 

of the included permits. EPA agrees that 

it would not be appropriate to approve 

Condition 6 of each permit into the SIP 

and propose the condition’s exclusion. 

EPA is proposing to determine that 

these control measures, and the permits 

that contain them, satisfy CAA 

§ 110(a)(2)(A) and 172(c)(6) 

requirements and 75 FR 35520. It 

should be noted that the emission limit 

established for MPW in the control 

strategy of the state’s nonattainment 

plan relies on a pound/hour (lb/hr) limit 

expressed an averaging time (e.g. as 21- 

day average) across multiple units.9 In 

accordance with EPA policy, the 21-day 

average limit is set at a lower level than 

the emission rate used in the attainment 

demonstration; the relationship between 

these two values is discussed in more 

detail in the following section. 

2. Longer Term Averaging 

As discussed in the April 2014 

guidance, and in section III. Attainment 

Demonstration and Longer Term 

Averaging in this preamble, EPA has 

recommended that averaging times in 

SIP emission limits should not exceed 

the applicable NAAQS averaging time, 

in this case 1-hour, however, EPA has 

acknowledged that a 1-hr emission rate 

limit may be difficult to achieve at some 

facilities. As such EPA provided 

guidance for establishing longer term 

averaging limits based on a supportable 

downward adjustment of the critical 

emissions value. The critical emissions 

value is the 1-hr averaged emission rate 

that dispersion modeling predicts 

would attain the NAAQS. 

The control strategy included in the 

state’s nonattainment SIP allows MPW 

to meet a compliance formula based on 

a 21-day averaging period across 

multiple units running alone or in 

combination. The formula incorporates 

a weighting function derived from the 

modeling results of the individual units 

(Units 7, 8 and 9), and downward 

adjustments of the critical emissions 

values. A separate downward 

adjustment was calculated for each unit 

using five years of unit-specific CEMS 

data, 2010–2014; the state considered 

this data to be representative of the 

boilers’ operations into the future, and 

reflect the fact that each unit is emitting 

from a separate stack. The 1-hour 

emissions value of 1,153 lbs/hr used in 

the formula incorporates the adjustment 

to a longer term limit according to the 

ratio of the 99th percentile 21-day 

average emission rate to the 99th 

percentile 1-hr emission rates from the 

CEMS data. Because the 1,153 lbs/hr 

value was derived from all 3 units 

operating together additional model 

runs were needed to ensure the formula 

was protective under other operating 

scenarios, with combinations of one or 

two units operating. The formula 

provides flexibility for MPW to run their 

three coal units alone or in combination 

in such a way that the NAAQS will be 

protected at all times. Because the units 

have different dispersion characteristics, 

the formula weighs each unit’s 

individual emissions such that the 

critical modeled value in the formula is 

always protected. 

To determine the longer term average 

limit, the state determined the 

individual variability of each unit from 

the 2010–2014 CEMS data as described 

above. The variability value ratios of the 

99th percentile 21-day average and 99th 

percentile hourly values were 0.71, 0.90, 

0.63 for the three units respectively. The 

state determined a critical value for each 

of these units individually using their 

respective variability and stack 

characteristics. In the first modeling 

scenario (the ‘‘All’’ run) the state 

determined the hourly critical values for 

Units 7,8,9 as 250 lbs/hr, 1000 lbs/hr, 

and 120 lbs/hr respectively, so 1,370 

lbs/hr total from the 3 units. Applying 

the individual unit variability, the 

equivalent 21 day limits would be 177.5 

lbs/hr, 900.0 lbs/hr, and 75.6 lbs/hr 

respectively which when added together 

is 1,153 lbs/hr, the value that becomes 

the basis of the compliance formula. 

The state then modeled 7 combinations 

of emissions scenarios using the 

individual unit stack characteristics that 

all demonstrated compliance with the 

NAAQS and accounted for individual 

variability of each unit. These scenarios 

consisted of 3 model runs where the 

individual units were operating alone 

and 4 model runs with various 

combinations of units operating. Each 

run had its own hourly critical modeled 

value demonstrating compliance and 

these 7 runs formed the basis for the 

weights in the formula to ensure 1,153 

lbs/hr was always protective of all the 

individual critical values modeled. This 

provided modeled emission rates such 

that a weighted formula could be 

derived such that any combination of 

emissions from the three individual 

units would always be at or below the 

value of 1,153 lbs/hr as expressed in the 

formula. Because the stacks have 

different dispersion characteristics and 

the modeled scenarios have different 

critical emission values, the formula 

derived contains different weights or 

multipliers for each unit’s actual hourly 

emissions, but the weights are such that 

no individual unit operating alone or a 

combination of units will cause a 

NAAQS violation as long as the formula 

criteria as expressed in the permit are 

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10The formula for MPW, as specified in their 

permit is as follows: 

‘‘The owner or operator shall maintain a file of 

computations to show the total hourly emission 

level for SO2. The owner or operator shall use the 

total hourly SO2 emission rates to calculate and 

record the average SO2 emission rate for each 

calendar day. Effective January 1, 2017, the owner 

or operator shall use the daily average SO2 emission 

rates to demonstrate compliance with the 21-day 

rolling average as calculated below: SO2 = 

2.03*(Unit 7) + 0.84*(Unit 8) + 1.22*(Unit 9) 

Where, SO2 = total emissions, in pounds per hour, 

of sulfur dioxide from Unit 7, Unit 8 and Unit 9 

Unit 7 = 24-hour average sulfur dioxide emission 

rate, lb/hr, for Unit 7 

Unit 8 = 24-hour average sulfur dioxide emission 

rate, lb/hr, for Unit 8 

Unit 9 = 24-hour average sulfur dioxide emission 

rate, lb/hr, for Unit 9. 

11The Des Moines monitor is approximately 5 km 

from the nearest SO2 source. The county emissions 

are approximately 163 tpy. The Lake Sugema 

monitor is more than 10 km away from the nearest 

SO2 source. The state’s nonattainment SIP indicates 

that are no reported major or minor sources of SO2

emissions in the county. 

12The EPA’s SO2 National Ambient Air Quality 

Standards Designations Modeling TAD describes an 

appropriate methodology of calculating temporally 

varying background monitored concentrations by 

hour of day and season (excluding periods when 

the source in question is expected to impact the 

monitored concentration). The methodology is to 

use the 99th percentile concentration for each hour 

of the day by season and average across 3 years, 

excluding periods when the dominant source(s) are 

influencing the monitored concentration (i.e., 99th 

percel1tile, or 4th highest, concentrations for hour 

l for January or winter, 99th percentile 

concentrations for hour 2 for January or winter, 

etc.). 

met.10 Table 1 shows that during each 

operational scenario at MPW, combined 

with the control strategies for GPC and 

Monsanto, the current maximum 

allowable permitted emission rates from 

LGS, and background concentrations, 

will result in attainment of the 1-hour 

SO2 NAAQS. 

TABLE 1—CUMULATIVE MODELING RESULTS WITH EACH MPW OPERATING SCENARIO

MPW operating scenario 

Cumulative 

model result 

(μg/m3) 

1-hour SO2

NAAQS 

(μg/m3) 

All ............................................................................................................................................................................. 182.76 196 

U9 Off ...................................................................................................................................................................... 182.71 ........................

U8 Off ...................................................................................................................................................................... 183.66 ........................

U7 Off ...................................................................................................................................................................... 182.88 ........................

U7 Only .................................................................................................................................................................... 183.96 ........................

U8 Only .................................................................................................................................................................... 181.86 ........................

U9 Only .................................................................................................................................................................... 187.78 ........................

Based on a review of the state’s 

submittal, the EPA believes that the 21- 

day average limit for MPW provides a 

suitable alternative to establishing a 1- 

hour average emission limit for this 

source. The state has used a suitable 

data base in an appropriate manner and 

has thereby applied an appropriate 

adjustment, yielding an emission limit 

formula that has comparable stringency 

to the 1-hour average limit that the state 

determined would otherwise have been 

necessary to provide for attainment. 

While the 21-day average limit allows 

occasions in which emissions may be 

higher than the level that would be 

allowed with the 1-hour limit, the 

state’s limit compensates by requiring 

average emissions to be lower than the 

level that would otherwise have been 

required by a 1-hour average limit. For 

reasons described above and explained 

in more detail in EPA’s April 2014 

guidance, EPA finds that appropriately 

set longer term average limits provide a 

reasonable basis by which 

nonattainment plans may provide for 

attainment. Based on its review of this 

general information as well as the 

particular information in state’s plan, 

the EPA finds that the 21-day average 

limit formula for MPW in combination 

with other limitations in the state’s 

plan, will provide for attainment of the 

NAAQS. 

E. Background Concentrations 

The state reviewed its statewide SO2

monitoring network to determine an 

appropriate background monitoring 

location- the Davenport SO2 monitoring 

site. As noted by the state, the ideal 

background location chosen represents 

the contributions from all sources not 

explicitly modeled. Because the 

monitoring locations in Muscatine, IA 

are impacted significantly by sources 

that were included in the modeling 

analysis, those monitors were 

eliminated as an option to represent the 

background concentrations in the area. 

Of the remaining monitor locations, two 

are situated adjacent to industrialized 

areas (Cedar Rapids and Clinton), and, 

as such, would likely be an overestimate 

of the concentrations caused by 

background sources. The state 

determined that the Des Moines and 

Lake Sugema monitors were impacted 

by less SO2 emissions than what would 

be represented by the background for 

the Muscatine nonattainment area—and, 

as such, would likely be an 

underestimation of the concentrations of 

SO2 caused by background sources.11

The state determined that the 

Davenport SO2 monitoring location was 

appropriate for estimating background 

concentrations for the following 

reasons: (1) The Davenport monitor is 

the nearest location to the 

nonattainment area (other than those 

monitors located in Muscatine already 

excluded); (2) the Davenport monitor is 

near a moderately industrialized area, 

but is not situated adjacent to those 

sources of emissions; (3) the Davenport 

monitor is in a county with a moderate 

amount of SO2 emissions; and (4) using 

the Davenport monitor is consistent 

with the meteorological data used for 

the analysis. For these reasons the state 

believed that the Davenport monitoring 

location could account for the sources 

screened out of the control strategy such 

as emissions from natural sources, major 

and minor point sources not included in 

the analysis, mobile (onroad and 

nonroad) sources, and nonpoint sources. 

The state utilized temporally varying 

background concentrations by hour and 

season from the Davenport SO2

monitoring location to account for 

contributions to the predicted impacts 

from background SO2 sources. To 

account for seasonal and diurnal 

variations in the background levels, the 

state based the background 

concentration on the average diurnal 

and seasonal concentration pattern 

observed at the Davenport monitor 

during the years 2011–2013. For the 

years 2011–2013, the 99th percentile 

monitor concentration was calculated 

for each hour of the day by season and 

then averaged across the three years.12

The state also averaged the 2011–2013 

design values for Cedar Rapids, 

Davenport, Des Moines, and Lake 

Sugema to determine if that number, 

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13The LGS facility is located immediately south 

of the nonattainment area. During the designations 

process, this source was shown to be insignificant 

during predicted exceedances at the Musser Park 

monitor, but as it was possible that the source could 

cause a concentration gradient in the vicinity of the 

southern portion of the nonattainment area, it was 

included in the analysis. 

14Per EPA’s August 23, 2010, ‘‘Guidance 

Concerning the Implementation of the 1-hour SO2

NAAQS for the Prevention of Significant 

Deterioration Program’’, the SIL is 3 ppb. The EPA 

plans ‘‘to undertake rulemaking to adopt a 1-hour 

SO2 SIL value. However, until such time as a 1-hour 

SO2 SIL is defined in the PSD regulations, we are 

providing an interim SIL of 3 ppb, which we intend 

to use as a screening tool for completing the 

required air quality analyses for the new 1-hour SO2

SIL NAAQS under the federal PSD program at 40 

CFR 52.21. We are also making the interim SIL 

available to States with EPA-approved 

implementation plans containing a PSD program to 

use at their discretion.’’ The SIL remains an interim 

SIL until rulemaking is complete. 

15To convert from mg/m3 to ppb, the mg/m3 value 

was divided by 2.6. 

10.5 ppb, would be appropriate as 

background. The state called this the 

Tier 1 value. The Tier 1 value of 10.5 

ppb is higher than all but one of the 

seasonal/diurnal concentrations. This 

shows that the use of the Tier 1 value 

for all hours and seasons would have 

been too high to represent the variable 

background concentrations. The EPA 

agrees with the state’s proposal that the 

method of using temporally varying 

background monitor concentrations by 

hour and season from the Davenport 

monitoring location, as it is calculated 

from the 99th percentile, is appropriate. 

F. Summary of Results 

The modeling analysis was conducted 

in two phases. The first phase (Phase 1) 

of the analysis was a screening analysis 

to determine the sources that needed to 

be included in the control strategy 

analysis. The second phase (Phase 2) of 

the analysis was used to develop the 

control strategy and included all 

significant sources identified in Phase 1. 

1. Phase 1—Preliminary Analysis 

This phase was accomplished by 

modeling actual emissions from GPC, 

MPW, Monsanto, and LGS and 

allowable emissions from SSAB and 

Gerdau and then determining the 

percentage of predicted NAAQS 

exceedances within the nonattainment 

area to which each facility significantly 

contributed. In this way, the state 

determined that GPC contributed to 100 

percent of the NAAQS exceedances, 

MPW contributed to approximately 25 

percent of the NAAQS exceedances, 

Monsanto contributed to approximately 

1 percent of the NAAQS exceedances, 

and LGS contributed to approximately 5 

percent of the NAAQS exceedances. 

Both SSAB and Gerdau each modeled 

less than a 1 percent contribution to the 

NAAQS exceedance days within the 

nonattainment area. Therefore, only 

GPC, MPW, Monsanto and LGS were 

determined to have enough potential 

contribution to NAAQS exceedances to 

be evaluated further.13

The state then further subdivided the 

sources by classifying the significant 

contributors as either a primary or a 

secondary contributor. If the facility’s 

significant contribution to the predicted 

NAAQS exceedance was greater than or 

equal to half of the total concentration 

(minus background) it was considered a 

primary contributor. If the facility’s 

contribution was less than half of the 

total concentration, but still more than 

the Significant Impact Level (SIL) it was 

considered a secondary contributor.14

GPC was identified as a primary 

contributor to all predicted NAAQS 

exceedances within the nonattainment 

area. GPC’s max potential contribution 

was estimated as 3,180 mg/m3 (or 

approximately 1,223 ppb).15 GPC’s 

contribution to the predicted NAAQS 

exceedance was greater than or equal to 

half of the total concentration (minus 

background) 100 percent of the time. 

MPW, Monsanto and LGS were 

identified as secondary contributors. 

MPW’s max potential contribution was 

estimated as 107 mg/m3 (or 

approximately 41 ppb). MPW’s 

contribution to the predicted NAAQS 

exceedance was less than half of the 

total concentration, but still more than 

SIL (minus background) 26 percent of 

the time. Monsanto’s max potential 

contribution was estimated as 28 mg/m3

(or approximately 11 ppb). Monsanto’s 

contribution to the predicted NAAQS 

exceedance was less than half of the 

total concentration, but still more than 

SIL (minus background) less than 1 

percent of the time. LGS’s maximum 

potential contribution was estimated as 

59 mg/m3 (or approximately 22.7 ppb). 

LGS’s contribution to the predicted 

NAAQS exceedance was less than half 

of the total concentration, but still more 

than SIL (minus background) 2 percent 

of the time. As such, only GPC, MPW, 

Monsanto and LGS were included in the 

second phase of the analysis. 

2. Phase 2—Control Strategy 

Development 

Sources identified in Phase 1 (GPC, 

MPW, Monsanto, and LGS) as being 

significant contributors were modeled at 

their maximum permitted allowable 

emission rates. Using the process 

summarized below, more restrictive 

maximum permitted emission rates 

were developed where necessary to 

ensure modeled attainment. 

To start its Phase 2 analysis, the state 

provided GPC with a model input file 

that included its emission units as well 

as the exceedance receptors to which it 

contributed. The state’s nonattainment 

SIP submittal indicates that GPC 

reviewed the input data for accuracy 

and then mitigated all modeled 

exceedances caused by the GPC facility 

alone. 

The remaining facilities (MPW, 

Monsanto, and LGS) were then added to 

the analysis with their maximum 

permitted allowable emission rates and 

the cumulative impacts were 

determined across the entire 

nonattainment area. According to the 

state’s nonattainment SIP submittal, the 

remaining predicted exceedances were 

then discussed with Monsanto and 

MPW. As a result of those discussions, 

additional control measures were 

developed for those facilities and are 

incorporated in construction permits 

submitted as part of the SIP revision. 

See section V.B. in this preamble for 

more information regarding the control 

measures. 

Monsanto proposed to decrease the 

emission rate for Boiler 8 at its facility 

to mitigate exceedances just north of its 

property. MPW proposed multiple 

model scenarios with combined 

operation of Units 7, 8, and 9. 

Regardless of the operational scenario, 

the unit/units were modeled at an 

equation cap of 1,153 lb/hr SO2. The 

model results varied depending on 

which combination of boilers was 

running. Each of the modeling scenarios 

(with background included) resulted in 

concentrations below the 1-hour SO2

NAAQS. The highest modeled SO2

concentration was 187.87 ug/m3 which 

included the operation of just Unit 9 at 

MPW. See section IV.D.2. Longer Term 

Averaging limits, in this preamble, for 

more discussion of the equation used to 

determine compliance with the NAAQS 

for each MPW modeling scenario. 

These results indicate that the 

controls established in the construction 

permits for MPW, GPC and Monsanto 

result in attainment of the NAAQS, and 

as such, additional controls were not 

necessary for LGS in order for the area 

to attain. EPA agrees with the state’s 

determination that its control strategy 

analysis results in modeled 

concentrations throughout the 

nonattainment area that are at or below 

75 ppb/196.4 ug/m3. Based upon 

monitoring data discussed in section 

V.B. RACM/RACT in this preamble, 

EPA expects that the Muscatine area 

will attain by the attainment date, 

August 5, 2018. 

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16The projections don’t consider operational, 

physical, supply/demand, or other factors that 

typically curb actual emissions to values below the 

maximum permitted allowable rate. There is 

potential for the actual attainment-year emissions to 

be lower than those in Table 2. 

V. Review of Other Plan Requirements 

A. Emissions Inventory and the 

Quantification of Emissions 

Section 172(c)(3) of the CAA requires 

that the state’s nonattainment plan 

include a comprehensive, accurate, 

current inventory of actual emissions 

from all sources of the relevant 

pollutant or pollutants in such area, 

including such periodic revisions as the 

Administrator may determine necessary 

to assure that the requirements of this 

part are met. Section 172(c)(4) of the 

CAA requires that the state’s 

nonattainment plan expressly identify 

and quantify the emissions, if any, of 

any such pollutant or pollutants which 

will be allowed, in accordance with 

section 703(a)(1)(B) of the CAA, from 

the construction and operation of major 

new or modified stationary sources in 

each such area. The plan shall 

demonstrate to the satisfaction of the 

Administrator that the emissions 

quantified for this purpose will be 

consistent with the achievement of 

reasonable further progress and will not 

interfere with attainment of the 

applicable National Ambient Air 

Quality Standard by the applicable 

attainment date. 

The emissions inventory and source 

emission rate data for an area serve as 

the foundation for air quality modeling 

and other analyses that enable states to: 

(1) estimate the degree to which 

different sources within a 

nonattainment area contribute to 

violations within the affected area; and 

(2) assess the expected improvement in 

air quality within the nonattainment 

area due to the adoption and 

implementation of control measures. As 

noted above, the state must develop and 

submit to EPA a comprehensive, 

accurate and current inventory of actual 

emissions from all sources of SO2

emissions in each nonattainment area, 

as well as any sources located outside 

the nonattainment area which may 

affect attainment in the area. See the 

April 2014 guidance. Additional 

emission inventory information was 

discussed in section IV.C Emissions 

Data in this preamble. A brief summary 

is provided later in this action. 

The base year inventory establishes a 

baseline that is used to evaluate 

emissions reductions achieved by the 

control strategy and to assess reasonable 

further progress requirements. The 

state’s nonattainment SIP noted that, at 

the time, the most recent and available 

triennial inventory year was 2011 and 

the stated found that it served as a 

suitable base year. Table 2 provides the 

2011 SO2 emissions inventory data for 

sources within and outside of the 

nonattainment the area (data have been 

rounded to the nearest whole number). 

TABLE 2—BASE LINE EMISSION INVENTORY FOR THE MUSCATINE, IA NONATTAINMENT AREA

Facility 

2011 SO2

emissions 

(tpy) 

Base Line Emissions Inventory for the Muscatine NAA 

Inside of the NAA ........................................................................ Grain Processing Corporation ................................................... 10,810 

Muscatine Power and Water ..................................................... 2,374 

Monsanto ................................................................................... 537 

HNI Corp.—North Campus ........................................................ <1 

HNI Corp.—Central Campus ..................................................... <1 

H.J. Heinz L.P. ........................................................................... <1 

Union Tank Car Co. ................................................................... <1 

Outside of the NAA ..................................................................... Louisa Generating Station ......................................................... 7,304 

All of Muscatine County .............................................................. Onroad Mobile ........................................................................... 3 

Nonroad Mobile .......................................................................... 2 

Area Sources ............................................................................. 10 

Fires ........................................................................................... 9 

Total ..................................................................................... .................................................................................................... 21,049 

Although not part of the state’s 

discussion of its 2011 baseline 

emissions inventory, the state’s 

nonattainment SIP also provides 2013 

SO2 data for Gerdau and SSAB in 

Muscatine County and Linwood and 

Lafarge in Scott County. However, the 

state provided this as a sum for the 

sources by county (e.g., the sum of 

Gerdau and SSAB was 254 tpy and the 

sum of Linwood and Lafarge was 1,539 

tpy). Gerdau and SSAB are 

approximately 8–9 km away from the 

nonattainment boundary and Linwood 

and Lafarge are approximately 20 km 

away from the nonattainment area 

boundary. 

As already noted, the state’s 

nonattainment SIP must identify and 

quantify the emissions which will be 

allowed from the construction and 

operation of major new or modified 

stationary sources in the area (see CAA 

§ 172(c)(4)). The state must demonstrate 

that such emissions will be consistent 

with RFP requirements and will not 

interfere with attainment of the 1-hr SO2

NAAQS. These requirements are met by 

the states preconstruction permitting 

program and implementation of the 

Nonattainment New Source Review 

Rules (NNSR). See section C. 

Nonattainment New Source Review in 

this preamble for more information. 

According to EPA’s April 2014 SO2

guidance, the SIP should also include a 

projected attainment year inventory that 

includes estimated emissions for all 

emission sources of SO2 that were 

determined to have an impact on the 

affected nonattainment area for the year 

in which the area is expected to attain 

the standard, consistent with the 

attainment demonstration. The 

inventory should reflect projected 

emissions for the attainment year for all 

SO2 sources in the nonattainment area. 

The state’s nonattainment SIP provided 

a projected inventory only for the 

controlled sources, as provided in table 

3. The inventory was developed 

assuming each SO2 source operates 

8,760 hours per year at its permitted 

maximum allowable emission rate.16

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17Appendix B, C and D of the state’s 

nonattainment SIP contain the Federally 

enforceable air construction permits that define 

RACM/RACT requirements. The RACM/RACT 

limits taken to comply with the NAAQS are 

specifically noted in each permit via footnotes in 

the permits. 

18The state’s estimation of a 90 percent reduction 

in SO2 emissions is based off of the control 

efficiency readily achieved by the types of 

scrubbers being installed. 

TABLE 3—PROJECTED ALLOWABLE ANNUAL SO2 EMISSIONS FROM CONTROL STRATEGY SOURCES

Facility 

2018 SO2

emissions 

(tpy) 

Projected 2018 Emissions for the 

Controlled Sources 

Grain Processing Corporation .... 167 

Muscatine Power and Water ...... 5,051 

Monsanto .................................... 1,196 

The EPA is proposing to determine 

that the state has met the requirements 

of CAA § 172(c)(3) and 172(c)(4). 

B. RACM/RACT 

CAA § 172(c)(1) requires that the 

state’s nonattainment plan provide for 

the implementation of all RACM as 

expeditiously as practicable (including 

such reductions in emissions from 

existing sources in the area as may be 

obtained through the adoption, at a 

minimum, of RACT) and shall provide 

for attainment of the NAAQS. The 

state’s plan for attaining the 1-hour SO2

NAAQS in the Muscatine 

nonattainment area is based on a variety 

of control measures at GPC, MPW and 

Monsanto. Those measures were 

included in the state’s nonattainment 

SIP as construction permits.17

To ensure the SO2 NAAQS is attained, 

GPC must install additional scrubbers, 

comply with new and more stringent 

SO2 emission limits, and implement 

process modifications designed to ), 

andreduce SO2 emissions across 

numerous downstream sources. Table 

4–1 of the state’s nonattainment SIP lists 

all the sources included in the control 

strategy, contains descriptions of the 

control measures, and provides effective 

dates. Source specific permitted 

allowable emission rates, compliance 

and monitoring obligations, reporting 

and recordkeeping requirements, and 

implementation deadlines (where not 

immediately effectively upon permit 

issuance) are detailed in each 

construction permit included with the 

SIP submittal (appendix B of the state’s 

nonattainment plan). The GPC control 

strategy includes measures at 52 

emission points (EP) at the facility. In 

summary, those measures include 

EP0001.0 (Power House Boilers 1–4 and 

6–7) is subject to a more stringent SO2

emission limit based on natural gas 

combustion; EP546.0 is subject to a 

more stringent, source-specific SO2 limit 

of .0034 lb/hr; a requirement to continue 

to add sodium bisulfate to the steep 

water instead of sulfur dioxide in order 

to reduce SO2 emissions from the 

steeping operations and downstream 

processes; the establishment of source 

specific SO2 emission limits at 43 EPs 

and the required installation of 

scrubbers on EP015.0 (Germ Drier Nos. 

1 and 2), EP097.0 (Germ Drier No. 3), 

EP126.0 (Germ Drier No. 4), EP200N 

(Corn Steep Tank Nos. 1–30 and the 

North Wet Corn Drag), EP200S (Corn 

Steep Tank Nos. 31–62 and the South 

Wet Corn Drag), and EP279.0 (Wet 

Milling Nos. 1–6). The state expects the 

installation of the scrubbers to reduce 

SO2 emissions by up to 90 percent from 

those units.18

While the scrubber installations will 

not be completed by January 1, 2017, 

the desired target date discussed in 

EPA’s April 2014 guidance, the 

scrubbers will be operational as 

expeditiously as practicable. Based on 

permitted requirements, three of the six 

new scrubbers must be in operation no 

later than August 30, 2017, with the 

final scrubber operational by March 31, 

2018. The installation timetable 

accommodates factors such as 

demolition and construction schedules, 

structural modifications, ductwork 

design, and the addition of scrubber 

water treatment capacity. The state 

asserts in its nonattainment plan that 

the scrubber installation timeline will 

not delay or prevent timely attainment 

of the 1-hr SO2 NAAQS. 

It should also be noted that, on July 

14, 2015, GPC converted all of its coalfired boilers to natural gas. The state 

estimates that the fuel switch will result 

in a 96 percent reduction in the 

facility’s total SO2 emissions. In terms of 

2011 data, this fuel switch eliminated 

10,374 tons of SO2 emissions. The state 

believes, and the EPA agrees, that the 

fuel conversion from coal to natural gas 

in GPC’s boilers has significantly 

reduced measured ambient SO2

concentrations in Muscatine, as noted in 

Table 4. Based on existing air quality 

improvements the state projects that 

monitored attainment will be achieved 

by the attainment date. Appendix B of 

the state’s nonattainment SIP contains 

the Federally enforceable air 

construction permits that define GPC’s 

RACM/RACT requirements. 

TABLE 4—AIR MONITORING DATA FROM THE MUSSER PARK MONITOR

Design values (ppb) 99th Percentile daily max 1-hr SO2 concentrations 

(ppb) 

Monitor 

location 

1-hr SO2

NAAQS 

(ppb) 

2011–2013 2012–2014 2013–2015 2014–2016 2011 2012 2013 2014 2015 2016 

Musser 

Park.

75 ............... 217 194 158 113 248 224 179 180 116 45 

MPW is subject to several Federal 

programs that directly or indirectly 

affect SO2 emissions, including the Acid 

Rain provisions of title IV of the CAA, 

the Cross State Air Pollution Rule 

(CSAPR), and the CAA section 112 

Maximum Achievable Control 

Technology regulations more commonly 

known as the Mercury and Air Toxics 

Standards. However, the state did not 

rely on these Federal programs alone to 

address SO2 emissions. Instead, as per 

the states control strategy, MPW will 

comply with new SO2 emission limits 

that provide for attainment of the 

NAAQS. The control measures, 

described in table 4–2 of the state’s 

nonattainment SIP, account for seven 

possible operating scenarios involving 

the three coal-fired boilers (Units 7, 8, 

and 9). Permit No. 74–A–175–S3, issued 

to the facility in 2013, shows the SO2

emission limit for Units 7 and 8 was a 

combined maximum of 2,772 lb/hr. 

Permit No. 80–A–191–P2, issued to the 

facility in 2013, shows the SO2 emission 

limit for Unit 9 was 0.56 lb/MMBtu (a 

maximum daily average). Permit No. 

80–A–191–P4, issued to the facility in 

2016 as part of the control strategy of 

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19The unit’s 0.44 lbs/MMBtu emission rate is a 

Lowest Achievable Emission Rate (LAER). 

20The limit of 500 ppm by volume is from state 

rule. 

21The unit also has a 1.95 lbs/MMBtu based on 

a 3-hr rolling average limit is a Best Available 

Control Technology limit. 22See 74 FR 13547 (April 16, 1992). 

the state’s nonattainment SIP, shows the 

combined SO2 emissions from Units 7– 

9 must be less than 1,153 lbs/hr. 

The control strategy for MPW also 

addresses emission reductions from 

EP60 (Auxiliary Boiler). A permit issued 

to the facility in 2013, Permit No. 13– 

A–152, for the Auxiliary Boiler required 

that SO2 emissions be limited to limited 

0.44 lbs/MMBtu (expressed as the 

average of 3 runs) when burning fuel oil, 

and to 500 ppm by volume when 

burning natural gas or 

propane.19 thnsp;20 The permit issued 

to the facility in 2016, as part of the 

control strategy, Permit No. 13–A–152– 

S1, requires that the SO2 emissions be 

limited to 0.45 lb/hr and that the sulfur 

content of the distillate fuel oil 

combusted in the unit not exceed 15 

ppm. Appendix C of the state’s 

nonattainment SIP contains the 

Federally enforceable air construction 

permits that define MPW’s RACM/ 

RACT requirements. These permits are 

effective January 1, 2017. 

The control measures developed for 

Monsanto, described in table 4–3 of the 

state’s nonattainment SIP, establish 

lower emission limits on two sources— 

EP–195 (Boiler #8) and EP–234 (CAC 

Process Flare). The Boiler #8 control 

strategy includes a more stringent SO2

emission limit. A 2007 permit issued to 

the facility Permit No. 82–A–092–P9, 

limited the unit’s SO2 emissions to 

292.5 lb/hr. The permit issued to the 

facility in 2015, Permit No. 82–A–092– 

P11, as part of the control strategy, 

limits the unit’s SO2 emissions to 273 

lb/hr.21

The control strategy for the CAC 

Process Flare includes new SO2

emission limit that restricts the unit’s 

fuel use to natural gas only. A 2012 

permit issued to the facility, Permit No. 

88–A–001–S2, limited the unit’s SO2

emissions to 500 ppm by volume. The 

permit issued to the facility in 2015, 

Permit No. 88–A–001–S3, as part of the 

control strategy, limits the unit to 

burning only natural gas and the unit’s 

SO2 emissions to 0.02 lb/hr. Appendix 

D of the state’s nonattainment SIP 

contains the Federally enforceable air 

construction permits that define 

Monsanto’s RACM/RACT requirements. 

These permits are effective May 13, 

2015. 

The state has determined that these 

measures suffice to provide for 

attainment the attainment date, August 

5, 2018. EPA concurs and proposes to 

conclude that the state has satisfied the 

requirement in CAA § 172(c)(1) to adopt 

and submit all RACM as needed to 

attain the standards as expeditiously as 

practicable. 

C. Nonattainment New Source Review 

(NNSR) 

Section 172(c)(5) requires that the 

state’s nonattainment plan provisions 

shall require permits for the 

construction and operation of new or 

modified major stationary sources 

anywhere in the nonattainment area, in 

accordance with section CAA § 173. 

EPA approved the state’s nonattainment 

new source review rules on May 15, 

2014 (79 FR 27763). These rules provide 

for appropriate new source review for 

SO2 sources undergoing construction or 

major modification in the Muscatine 

nonattainment area without need for 

modification of the approved rules. 

Therefore, EPA concludes that the 

requirements of CAA § 172(c)(5) have 

been met. 

D. Reasonable Further Progress (RFP) 

Section 172(c)(2) requires that 

nonattainment plans include provisions 

addressing reasonable further progress 

(RFP). Reasonable further progress is 

defined in CAA § 171(1) as: ‘‘. . . such 

annual incremental reductions in 

emissions of the relevant air pollutant 

as are required by this part [part D] or 

may reasonably be required by the 

Administrator for the purpose of 

ensuring attainment of the applicable 

national ambient air quality standard by 

the applicable date.’’ 

As discussed in EPA’s April 2014 

guidance, this definition is most 

appropriate for pollutants that are 

emitted by numerous and diverse 

sources, where the relationship between 

any individual source and overall air 

quality is not explicitly quantified, and 

where NAAQS attainment requires 

inventory-wide emissions reductions. 

The SO2 NAAQS presents special 

circumstances because there are usually 

a limited number of well-defined 

sources affecting the area’s air quality 

and any emission control measures 

commonly result in swift improvements 

that typically occur in one step. As 

noted in the state’s nonattainment SIP, 

the EPA has interpreted that RFP is best 

construed as ‘‘adherence to an 

ambitious compliance schedule’’ in 

previous rulemaking.22

As previously noted in section V.B. 

RACT/RACM, in this preamble, the SO2

emission limits and application of 

control technologies established for 

Monsanto (effective on May 13, 2015), 

MPW (effective January 1, 2017) and for 

GPC occur on reasonable timelines. 

The state asserts that this plan 

requires that affected sources implement 

appropriate control measures as 

expeditiously as practicable in order to 

ensure attainment of the standard by the 

applicable attainment date. The state 

concluded that its plan therefore 

provides for RFP in accordance with the 

approach to RFP described in EPA’s 

guidance. EPA concurs and proposes to 

conclude that the plan provides for RFP 

as required by CAA § 172(c)(2). 

E. Contingency Measures 

Section 172(c)(9) of the CAA requires 

that the state’s nonattainment plan 

provide for the implementation of 

specific measures to be undertaken if 

the area fails to make reasonable further 

progress, or to attain the national 

primary ambient air quality standard by 

the attainment date applicable under 

this part. Such measures shall be 

included in the plan revision as 

contingency measures to take effect in 

any such case without further action by 

the State or the Administrator. 

EPA’s April 2014 guidance describes 

special features of SO2 planning that 

influence the suitability of alternative 

means of addressing the requirement in 

section 172(c)(9) for contingency 

measures for SO2, such that in particular 

an appropriate means of satisfying this 

requirement is for the state to have a 

comprehensive enforcement program 

that identifies sources of violations of 

the SO2 NAAQS and to undertake an 

aggressive follow-up for compliance and 

enforcement. 

The state’s nonattainment SIP 

provides that, after full implementation 

of the control strategy, contingency 

measures will be triggered if monitored 

ambient air quality records 1-hr SO2

NAAQS violation in the nonattainment 

area, or if the nonattainment area fails 

to meet RFP. If triggered, the state will 

evaluate culpabilities for the violation 

and will plan to complete the 

investigation within 3 months of the 

trigger. Where the investigation 

concludes unequivocally that SO2

emissions from one of the three sources 

in the control strategy is the cause of the 

recorded 1-hr SO2 NAAQS violation or 

failure to achieve RFP, the state will 

conduct a compliance evaluation and 

establish orders for the abatement or 

control of air pollution or make changes 

to the GPC, MPW, or Monsanto 

construction permits. Orders or 

construction permits will be issued 

within approximately 9 months of 

completion of the investigation and 

could include fuel switches, addition of 

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23 62 FR 27968 (May 22, 1997). 

controls, curtailment of production, 

reducing boiler operating loads, or other 

appropriate measures necessary to 

mitigate the violation. 

EPA proposes to approve the state’s 

plan for meeting the contingency 

measure requirement of CAA 

§ 172(c)(9). 

VI. Additional Elements of the State’s 

Submittal 

A. Compliance With Section 110(a)(2) of 

the CAA 

Section 172(c)(7) of the CAA requires 

nonattainment SIPs to meet the 

applicable provisions of CAA 

§ 110(a)(2). While the provisions of 

110(a)(2) address various topics, EPA’s 

past determinations suggest that only 

the § 110(a)(2) criteria which are linked 

with a particular area’s designation and 

classification are relevant to § 172(c)(7). 

This nonattainment SIP submittal 

satisfies all applicable CAA § 110(a)(2) 

criteria, as evidenced by the state’s 

nonattainment new source review 

program which addresses 110(a)(2)(I), 

the included control strategy, and the 

associated emissions limits which are 

relevant to 110(a)(2)(A). In addition, on 

July 26, 2013, Iowa submitted to EPA an 

infrastructure SIP to demonstrate that 

the state has the necessary plans, 

programs, and statutory authority to 

implement the requirements of section 

110 of the CAA as they pertain to the 

2010 1-hr SO2 NAAQS. EPA will take 

action on the state’s SO2 infrastructure 

SIP in a separate rulemaking. The EPA 

is proposing to conclude that the state 

has meet the requirements of CAA 

§ 172(c)(7). 

B. Equivalent Techniques 

Section 172(c)(8) of the CAA states 

that upon application by any state, the 

Administrator may allow the use of 

equivalent modeling, emission 

inventory, and planning procedures, 

unless the Administrator determines 

that the proposed techniques are, in the 

aggregate, less effective than the 

methods specified by the Administrator. 

The state’s nonattainment SIP 

indicates that it followed existing 

regulations, guidance, and standard 

practices when conducting modeling, 

preparing the emissions inventories, 

and implementing its planning 

procedures. Therefore, the state did not 

use or request approval of alternative or 

equivalent techniques as allowed under 

of the CAA and the EPA is proposing to 

conclude that the state’s nonattainment 

SIP meets the requirements of CAA 

§ 172(c)(8). 

VII. EPA’s Proposed Action 

The EPA is proposing to approve the 

nonattainment SIP submission, which 

the state submitted to EPA on May 26, 

2016, for attaining the 2010 1-hour SO2

NAAQS for the Muscatine 

nonattainment area and for meeting 

other nonattainment area planning 

requirements. This SO2 attainment plan 

includes the state’s attainment 

demonstration for the Muscatine 

nonattainment area. The nonattainment 

area plan also addresses requirements 

for RFP, RACT/RACM, base-year and 

projection-year emission inventories, 

and contingency measures. 

The EPA has determined that the 

state’s nonattainment plan meets 

applicable requirements of the section 

172 of the CAA (107(c)(1) through (9). 

EPA’s analysis is discussed in this 

proposed rulemaking. 

The EPA is taking public comments 

for thirty days following the publication 

of this proposed action in the Federal 

Register. We will take all comments into 

consideration in our final action. 

VIII. Incorporation by Reference 

In this rule, EPA is proposing to 

include in a final EPA rule regulatory 

text that includes incorporation by 

reference. In accordance with 

requirements of 1 CFR 51.5, EPA is 

proposing to incorporate by reference 

the Iowa Regulations described in the 

amendments to 40 CFR part 52 set forth 

below. EPA has made, and will continue 

to make, these materials generally 

available through https://

www.regulations.gov and/or at the EPA 

Region 7 Office (please contact the 

person identified in the FOR FURTHER

INFORMATION CONTACT section of this 

preamble for more information). 

Therefore, these materials have been 

approved by EPA for inclusion in the 

State implementation plan, have been 

incorporated by reference by EPA into 

that plan, are fully Federally enforceable 

under sections 110 and 113 of the CAA 

as of the effective date of the final 

rulemaking of EPA’s approval, and will 

be incorporated by reference by the 

Director of the Federal Register in the 

next update to the SIP compilation.23

IX. Statutory and Executive Order 

Reviews 

Under the CAA, the Administrator is 

required to approve a SIP submission 

that complies with the provisions of the 

Act and applicable Federal regulations. 

42 U.S.C. 7410(k); 40 CFR 52.02(a). 

Thus, in reviewing SIP submissions, 

EPA’s role is to approve state choices, 

provided that they meet the criteria of 

the CAA. Accordingly, this proposed 

action merely approves state law as 

meeting Federal requirements and does 

not impose additional requirements 

beyond those imposed by state law. For 

that reason, this proposed action: 

• Is not a significant regulatory action 

subject to review by the Office of 

Management and Budget under 

Executive Orders 12866 (58 FR 51735, 

October 4, 1993) and 13563 (76 FR 3821, 

January 21, 2011); 

• Does not impose an information 

collection burden under the provisions 

of the Paperwork Reduction Act (44 

U.S.C. 3501 et seq.); 

• Is certified as not having a 

significant economic impact on a 

substantial number of small entities 

under the Regulatory Flexibility Act (5 

U.S.C. 601 et seq.); 

• Does not contain any unfunded 

mandate or significantly or uniquely 

affect small governments, as described 

in the Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4); 

• Does not have Federalism 

implications as specified in Executive 

Order 13132 (64 FR 43255, August 10, 

1999); 

• Is not an economically significant 

regulatory action based on health or 

safety risks subject to Executive Order 

13045 (62 FR 19885, April 23, 1997); 

• Is not a significant regulatory action 

subject to Executive Order 13211 (66 FR 

28355, May 22, 2001); 

• Is not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the CAA; and 

• Does not provide EPA with the 

discretionary authority to address, as 

appropriate, disproportionate human 

health or environmental effects, using 

practicable and legally permissible 

methods, under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

The SIP is not approved to apply on 

any Indian reservation land or in any 

other area where EPA or an Indian tribe 

has demonstrated that a tribe has 

jurisdiction. In those areas of Indian 

country, the rule does not have tribal 

implications and will not impose 

substantial direct costs on tribal 

governments or preempt tribal law as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Reporting and recordkeeping 

requirements, Sulfur oxides. 

mstockstill on DSK30JT082PROD with PROPOSALS

Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 40099 

Dated: August 9, 2017. 

Edward H. Chu, 

Acting Regional Administrator, Region 7. 

For the reasons stated in the 

preamble, EPA proposes to amend 40 

CFR part 52 as set forth below: 

Part 52—APPROVAL AND 

PROMULGATION OF 

IMPLEMENTATION PLANS 

■ 1. The authority citation for part 52 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart Q—Iowa 

■ 2. Amend § 52.820 by: 

■ a. In the table in paragraph (d), adding 

entries ‘‘(112)’’ through ‘‘(169)’’ in 

numerical order; and 

■ b. In the table in paragraph (e), adding 

an entry ‘‘(47)’’ in numerical order. 

The additions read as follows: 

§ 52.820 Identification of plan. 

* * * * * 

(d)* * * 

EPA-APPROVED IOWA SOURCE-SPECIFIC ORDERS/PERMITS

Name of source Order/permit No. State effective 

date EPA approval date Explanation 

*******

(112) Grain Processing Corporation.Permit No. 95–A–374–S4 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(113) Grain Processing Corporation.Permit No. 15–A–078 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(114) Grain Processing Corporation.Permit No. 79–A–194–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(115) Grain Processing Corporation.Permit No. 71–A–067–S4 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(116) Grain Processing Corporation.Permit No. 75–A–087–S1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(117) Grain Processing Corporation.Permit No. 72–A–199–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(118) Grain Processing Corporation.Permit No. 74–A–014–S1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(119) Grain Processing Corporation.Permit No. 74–A–015–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(120) Grain Processing Corporation.Permit No. 75–A–353–S2 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(121) Grain Processing Corporation.Permit No. 79–A–195–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(122) Grain Processing Corporation.Permit No. 80–A–149–S5 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

mstockstill on DSK30JT082PROD with PROPOSALS

40100 Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 

EPA-APPROVED IOWA SOURCE-SPECIFIC ORDERS/PERMITS—Continued 

Name of source Order/permit No. State effective 

date EPA approval date Explanation 

(123) Grain Processing Corporation.Permit No. 80–A–150–S5 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(124) Grain Processing Corporation.Permit No. 85–A–031–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(125) Grain Processing Corporation.Permit No. 85–A–032–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(126) Grain Processing Corporation.Permit No. 85–A–038–P1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(127) Grain Processing Corporation.Permit No. 85–A–135–P1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(128) Grain Processing Corporation.Permit No. 90–A–111–S1 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(129) Grain Processing Corporation.Permit No. 91–A–068–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(130) Grain Processing Corporation.Permit No. 93–A–110–P1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(131) Grain Processing Corporation.Permit No. 92–A–383–S2 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(132) Grain Processing Corporation.Permit No. 92–A–385–S1 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(133) Grain Processing Corporation.Permit No. 94–A–055–S1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(134) Grain Processing Corporation.Permit No. 94–A–061–S1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(135) Grain Processing Corporation.Permit No. 02–A–781–S2 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(136) Grain Processing Corporation.Permit No. 02–A–782–S2 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

mstockstill on DSK30JT082PROD with PROPOSALS

Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 40101 

EPA-APPROVED IOWA SOURCE-SPECIFIC ORDERS/PERMITS—Continued 

Name of source Order/permit No. State effective 

date EPA approval date Explanation 

(137) Grain Processing Corporation.Permit No. 09–A–482–S2 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(138) Grain Processing Corporation.Permit No. 10–A–563–S1 .. 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(139) Grain Processing Corporation.Permit No. 15–A–200 ........ 3/25/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(140) Grain Processing Corporation.Permit No. 15–A–201 ........ 3/25/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(141) Grain Processing Corporation.Permit No. 15–A–202 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(142) Grain Processing Corporation.Permit No. 15–A–203 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(143) Grain Processing Corporation.Permit No. 15–A–204 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(144) Grain Processing Corporation.Permit No. 15–A–205 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(145) Grain Processing Corporation.Permit No. 15–A–206 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(146) Grain Processing Corporation.Permit No. 15–A–207 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(147) Grain Processing Corporation.Permit No. 15–A–208 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(148) Grain Processing Corporation.Permit No. 15–A–209 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(149) Grain Processing Corporation.Permit No. 15–A–480 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(150) Grain Processing Corporation.Permit No. 15–A–481 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

mstockstill on DSK30JT082PROD with PROPOSALS

40102 Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 

EPA-APPROVED IOWA SOURCE-SPECIFIC ORDERS/PERMITS—Continued 

Name of source Order/permit No. State effective 

date EPA approval date Explanation 

(151) Grain Processing Corporation.Permit No. 15–A–482 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(152) Grain Processing Corporation.Permit No. 15–A–483 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(153) Grain Processing Corporation.Permit No. 15–A–213 ........ 1/26/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(154) Grain Processing Corporation.Permit No. 15–A–484 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(155) Grain Processing Corporation.Permit No. 15–A–485 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(156) Grain Processing Corporation.Permit No. 15–A–486 ........ 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(157) Grain Processing Corporation.Permit No. 15–A–326 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(158) Grain Processing Corporation.Permit No. 03–A–471–S1 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(159) Grain Processing Corporation.Permit No. 05–A–926–S4 .. 2/15/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(160) Grain Processing Corporation.Permit No. 06–A–1261–S1 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(161) Grain Processing Corporation.Permit No. 11–A–338–S1 .. 7/6/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(162) Grain Processing Corporation.Permit No. 15–A–354 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(163) Grain Processing Corporation.Permit No. 15–A–199 ........ 12/10/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(164) Muscatine Power and 

Water.

Permit No. 13–A–152–S1 .. 3/2/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

mstockstill on DSK30JT082PROD with PROPOSALS

Federal Register / Vol. 82, No. 163 / Thursday, August 24, 2017 / Proposed Rules 40103 

EPA-APPROVED IOWA SOURCE-SPECIFIC ORDERS/PERMITS—Continued 

Name of source Order/permit No. State effective 

date EPA approval date Explanation 

(165) Muscatine Power and 

Water.

Permit No. 74–A–175–S4 .. 3/2/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(166) Muscatine Power and 

Water.

Permit No. 95–A–373–P3 .. 3/2/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(167) Muscatine Power and 

Water.

Permit No. 80–A–191–P3 .. 3/2/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(168) Monsanto .................... Permit No. 82–A–092–P11 5/13/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(169) Monsanto .................... Permit No. 88–A–001–S3 .. 5/13/15 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

2010 1-hr SO2 NAAQ Nonattainment Plan; Condition 6 of the permit is not part of the SIP; EPA– 

R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

(e)* * * 

EPA-APPROVED IOWA NONREGULATORY PROVISIONS

Name of nonregulatory SIP 

provision 

Applicable geographic or 

nonattainment area 

State submittal 

date EPA approval date Explanation 

*******

(47) 2010 1-hr SO2 National 

Ambient Air Quality Standard Nonattainment Plan.

A portion of Muscatine 

County.

5/26/16 [date of final publication in 

the Federal Register] 

and [Federal Register 

citation].

EPA–R07–OAR–2017–0416; FRL– 

XXXX–Region 7]. 

* * * * * 

[FR Doc. 2017–17736 Filed 8–23–17; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 63 

[EPA–HQ–OAR–2012–0133, FRL–9966–26– 

OAR] 

RIN 2060–AS79 

National Emission Standards for 

Hazardous Air Pollutants: Manufacture 

of Amino/Phenolic Resins 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: On October 8, 2014, the 

Environmental Protection Agency (EPA) 

finalized amendments to the National 

Emission Standards for Hazardous Air 

Pollutants (NESHAP) for the 

Manufacture of Amino/Phenolic Resins 

(APR). Subsequently, the EPA received 

three petitions for reconsideration of the 

final rule. The EPA is reconsidering and 

requesting public comment on issues 

related to the maximum achievable 

control technology (MACT) standards 

for continuous process vents (CPVs) at 

existing affected sources. The EPA is 

proposing to revise the MACT standard 

for back-end CPVs at existing affected 

sources based on hazardous air 

pollutant (HAP) emissions test data for 

back-end CPVs at existing sources for 

this source category submitted by 

petitioners. The EPA is also soliciting 

comments regarding the need to revise 

the standard for front-end CPVs at 

existing sources, and to extend the 

compliance date for the proposed 

revised emission limit for back-end 

CPVs at existing sources. Additionally, 

the EPA is proposing requirements for 

storage vessels at new and existing 

sources during periods when an 

emission control system used to control 

vents on fixed roof tanks is undergoing 

planned routine maintenance. The EPA 

is seeking comments only on the four 

issues specifically addressed in this 

notice: proposed revised back-end CPV 

MACT standards for existing sources, 

whether the EPA should modify the 

front-end CPV MACT standards for 

existing sources, whether the EPA 

should extend the compliance date for 

the proposed revised back-end CPV 

MACT standards for existing sources, 

and the proposed work practice 

standards for storage vessels during 

planned routine maintenance of 

emission control systems. In this 

rulemaking, the EPA is not reopening or 

requesting comment on any other 

aspects of the 2014 final amendments to 

the NESHAP for the Manufacture of 

APR, including other issues raised in 

petitions for reconsideration of the 2014 

rule. The EPA estimates this proposal, if 

mstockstill on DSK30JT082PROD with PROPOSALS